Monday, September 30, 2019
The program Leadership Innovation and Growth
The program Leadership, Innovation and Growth has been designed by the management at General Electric in order to facilitate team training in leading change. The strategic focus under the leadership of CEO Immelt has been the growth strategy through expanding businesses and creating new ones rather than through acquisitions.The business of GE that participated in the program was Power Generation, one of the companyââ¬â¢s oldest businesses. So far GEââ¬â¢s successes had been spurred by the headquarters.But now Immelt wanted to pass on the responsibility to the teams in the individual businesses. In order to facilitate this delegation of responsibility, the LIG program had been designed. The program facilitated team training to lead change and therefore to embed growth into the DNA of the company. The purpose of the program was to make innovation and growth a religion at GE.The program underscores the value of team training. Under the previous CEO Jack Welch, the strategic focus had been to maximize operational excellence. Now the new CEO Immelt wanted to combine innovation and organic growth with operational excellence to synergistic effects.This meant redesigning the organizational structure. Thus the business issue was the process of managing change. However the focus of traditional training programs had been individual training.Therefore when the employee returned to work on the new initiatives, he faced resistance from the rest of the team who had not been trained. The LIG program addressed this problem by focusing on team training so that the participating managers can reach consensus on the growth opportunities and the strategies to be implemented in capitalizing upon them.The industry in which GE Power Generation operates is characterized by a fast pace of change. As a result, the business must be able to manage change continuously. The business has been growing at a fast rate throughout the world. However it emerged from the program that the busine ss did not possess enough management capital to bring about the regulatory changes. This meant that the managers would have to rethink the strategies of developing human capital.The business was growing at a fast rate in emerging markets such as India, China and the Middle East and therefore the critical success factor was to expand the regulatory expertise accordingly. In addition, maintaining the momentum of the companyââ¬â¢s growth meant speeding up the product development process. The management needed to reach a consensus in how to implement these strategies in these areas.The management needed to figure out how to delegate authority to the different regions. For example, the natural response to new product development has been to maximize the extent of standardization. Variety and customization have always been disliked. However the challenge in front of the management was to develop products in country for country. Thus the product development process had to be redesigned in terms of delegating more authority to the regional managers.This involved cultural reorientation so that when the regional delegation did not go right, the blame did not fall on headquarters. The management also had to make sure that the process for global customers remained uniform across the regions and that there was a consensus on which contract terms should remain the same and which should be varied. These issues caused the need for the LIG program to be launched.The recommendations that have emerged from the program have been categorized into five areas. The first is the area of team training. This form of training enabled the managers to reach a consensus on what were potentially the barriers to change and how best to attack them. The second area was to consider both the hard barriers and the soft barriers to change. The hard barriers were defined as the existing organizational structure, capabilities and resources.The soft barriers were defined as the interactions between the members of the leadership teams individually and collectively. The management needed to address both barriers in order to manage change effectively. For example, GE Power Generation pursued the growth strategy of developing products in country for country. The barrier to implementing the strategy was the lacking in regulatory strength.
Sunday, September 29, 2019
Walking Contradiction
Now I know how parents may feel when their teenage kids are playing there depressing and gothic music at full blast at the middle of the night. It's clear that most people's opinions are that the lyrics featured in these gothic or metal bands are usually to do with some sort of bad language, death and violence. A feature most predominantly in many of Marilyn Manson's songs. A quote reveals how people judge him for every circumstance ââ¬Å"when a dude's getting bullied and shoots up the school and they blame it on Marilyn, and the heroinâ⬠This reveals people's attitude towards this individual. In any case people have their preferences and mine include Beegees. Now don't get me wrong, I'm not a golden oldie, but the best music had to have been made in the 70's or 80's. Perfectly good examples of these would have been Abba and Gloria Gaynor. Now neither of these people needed to promote sex, drugs and rock and roll to sell records, which is what seems to be happening today. Artists seem to swear more and more to sell more and more, now tell me is this right? Any ways don't get me wrong not every artist is like thatâ⬠¦ There are a handful of bands, which don't need negative aspects to sell their music. One band in particular is Kool and the gang, now if I may claim to liking the classic band does that necessarily mean that I must write off every modern day music as some of you people do. All of you people seem to be determined to write off any artists that bear the name Eminem or Marilyn Manson, or any artists that swear or have some sort of opinion not matching yours. The truth about the matter is that you use these individuals as scapegoats, so that you have something to blame when your child has done something wrong or you have something to blame for the way your child behaves. The fact of the matter is that music is a way of expression, and that no matter how or why people complain about aspects of it the reality is that you are powerless to stop any kind of music from coming out. But most importantly you are powerless to stop your children from listening to it. At the end people can listen to whatever type of music, from anything from Bob Marley's ââ¬Å"No woman No cryâ⬠to a more modern day song such as Rage Against The Machine's ââ¬Å"Bullet in the headâ⬠. I personally have gotten into Metallica recently, just like how a vampire needs his blood, I admittedly need to listen to the enlightening and somewhat depressing lyrics, as well as the bone crunching and indoctrinating guitar riffs daily. Without these I am happy to say that I would be a lifeless, dull and uncaring individual (One which requires someone to master him as a puppet). But with all this said hate and love have been with us from the beginning of time, and they will continue to be with us until the end. I only ask that people take in the fact that drugs and violence have always been in lyrics and will forever remain so, the key thing is to learn to deal with it! Show preview only
Saturday, September 28, 2019
Business Operations at BMW Essay Example | Topics and Well Written Essays - 5000 words - 2
Business Operations at BMW - Essay Example This research will begin with the statement that every other accolade that is used to describe a successful company can be used to describe Bayerische Motoren Werke AG, commonly referred to as BMW AG or simply BMW. This is because since 1916 that the company was established as a car, motorcycle and vehicle engine manufacturer, the company has not looked back in terms of growth and expansion. Headquartered in Germany, BMW specializes in several divisions of production, including Mini, BMW Motorsport, BMW I, and BMW Motorrad. Interestingly, BMW is not the kind of company that can be said to be operating in a monopoly market where competition is relatively absent. This is because the company operates in the automobile industry where there continues to be tough and stiff opposition from several other successful carmakers. Within Germany where the company is parented and the larger global market, there is very stiff opposition that the company faces by the day. Even within Germany alone, BMW is regarded as one of the ââ¬Å"Germany Big 3â⬠together with Audi and Mercedes Benz, all of which are engaged best-selling of luxury automobiles across the globe. On the larger global market, other competitors can be identified such as Toyota, Benz, and Kia. In such competitive environments, Film notes that the success of companies relies and depend largely on a critical understanding of their competing market, as well as the business operations dynamics that exist within these markets. Knowing oneââ¬â¢s customers and the best strategic options that best corresponds with the needs of customers is also important in ensuring survival on the competitive global market.
Friday, September 27, 2019
Financial Management essay Example | Topics and Well Written Essays - 2000 words
Financial Management - Essay Example Through the recent observations made by the organization it had been observed that Tulip Refractory is making a continuous loss for a span of consecutive five years but while the sister concern of the organization working with Cafe 88 is earning a year on year profit on a similar basis, i.e. no commercial price is to be charged from the office staff. From this study we have to analyze the reason for the loss of Tulip Refractory under the mentioned organization and how the sister concern of the main organization is earning profits working with Cafe 88(Analysis of Financial statement, n.d., and pp.1-10). Main activities of the Organization The main activities of Tulip Refractory are to provide meals, snacks and refreshment on working days to various staff of the organization. During the weekends the staffs of the Tulip Refractory are allowed to do some catering in private functions and ceremonies. Similar is the function of the Cafe 88 but we can observe a remarkable difference in the operation of both the catering services. This has put the main organization to take adequate steps based on the financial analysis thus conducted as follows. ... The main function of making an effective financial analysis of the company is to draw conclusion to arrive at a decision which will be in the best interest of the company. For achieving this purpose we employ the tool of ratio analysis under which three main aspects of a company are analyzed on the basis of its profitability, liquidity and efficiency/solvency. Liquidity Analysis The liquidity of the company means the repayable factor of a firm generally in cash form. The company which has assets which can be easily turned into cash for the purpose of meeting with the obligations of a company is called the liquidity analysis of the company. The liquidity of the firm has thus been found with the help of current ratio, quick ratio and cash ratio (Brigham, et. al., 2010, pp.93-110). Particulars (All values in pound) Tulip Refractory Cafe 88 Year 2011 2011 Current Assets 9000 16000 Current Liabilities 6000 4000 Current Ratio 1.50 4.00 Current Ratio mainly gives us an idea regarding the sh ot-term liability capacity of a firm. Higher the current ration more is its ability to repay its obligations. From the recent findings we can analyze that the repayment capacity of Tulip Refractory is much less in comparison to Cafe 88. This is because the liability of Cafe 88 is less with respect to the assets acquired by the catering firm. Particulars (All values in pound) Tulip Refractory Cafe 88 Year 2011 2011 Bank and cash 1000 14000 Debtors 5000 0 Total quick Assets 6000 14000 Current Liabilities 6000 4000 Quick Ratio 1.00 3.50 Quick ratio is known to be a much more conventional with respect to the current ratio; thus considered a better liquidity measure. Inventory in most of the companies is considered to be the most illiquid form of asset hence it
Thursday, September 26, 2019
International Tourism In The United States Of America Essay
International Tourism In The United States Of America - Essay Example A number of factors made it possible for people to increasingly visit different places and enjoy a change of scene from their usual environment. Among the factors is the rise of a middle class economy as workers benefited from income generated by working in new industries. This group of citizens had extra income to spend on vacations to different areas of the country occasionally taking a number of days (Shaffer, 2001). Additionally from the late eighteenth century, there were extensive developments in the transport and communication sectors within the US making it easy for people to travel and access information about specific areas they were interested in visiting. The construction of the railroad to link major cities by 1860 was an important step in furthering the increasing interest in tourism especially from entrepreneurs such as Walter Raymond who travelled to California to identify new areas of investment in the area of resort hotel in 1883. Following these developments, there were important developments in tourism as new destinations such as in San Francisco where the Cliff House became an area of interest as well as other places such as Yosemite national Park developed as a tourist attraction from the late 1850s (Shaffer, 2001). The developments in tourism industry from the 18th up to around 1940s majorly benefited the upper class and a few groups of people from the middle class. Additionally, tourism services offered by different players were disintegrated with service providers such as transport agencies, hotels keepers, tour operators and travel agents working as distinct groups within the sector. Each of the service providers worked independent of the other without closer collaborations with those running the hotels strictly being concerned with beds while those in transportation were only concerned with offering passenger services. However, the reality in
The Impact of Retail Distribution Review on Aviva Research Paper
The Impact of Retail Distribution Review on Aviva - Research Paper Example As the industry involves customers, financial advisors, and financial service providers, there can be conflicts of interest between customers and financial advisors or company and financial advisors. This is called agency problem which leads failure of customersââ¬â¢ trust on market. Financial regulatory bodies aim to employ certain regulations to resolve these issues. The Financial Services Act had been attempting to realize the retail market of investment and the reason for the failure of customers trust. In order to retain the public confidence and trust the FSA introduced the Retail Distribution Review (Personal Financial Society. 2010). This retail review was launched in June targeting the standard and quality of financial advisory services given to the customer in the financial services industry. Through the RDR, the FAS aims to develop a retail market where customers easily understand the information; the financial firms fairly treat their customers and the customers will have much confidence to invest in the market (CISI. n.d.). The approach has been quite influential to keep the resilience, efficiency and the productivity of the retail investment market. RDR is supposed to modernize the industry by bringing back customer confidence to the market by offering them the best choices to fulfill their pension and savings needs. RDR not only approaches to solve the significant issues influential behind some of the longtime problems, but it also considers the operating procedure of the overall market of retail investments. At the same time, the authority was concerned about the future operational procedures of the retail industry. To maintain a control and authority over the fair operation of the investment retail industry, RDR has considered and modified a number of previous policy initiatives. The modifications and introduction of some new policies have been carried out taking due consideration of all ofà the stakeholdersââ¬â¢ interests including the practitioners and the consumersââ¬â¢ representatives in this industry.
Wednesday, September 25, 2019
Islamic Banking System. Case of Malaysia Essay Example | Topics and Well Written Essays - 3250 words
Islamic Banking System. Case of Malaysia - Essay Example Similar to conventional banking, Islamic banks also collect the additional savings of people and then those savings are extended to those needy sectors of economy. In past, few researches have been developed to find out the relationship between the interest rate increase and funds flow from Islamic banking. This paper analyses the relationship between deposit returns of Islamic and conventional banks with an alternative econometric technique involving Units Root Test to estimate the presence of stationarity and Granger Causality test to estimate the linkage between the deposit returns of the two banking systems. The basic objective of this study is to find out the impact of the change in return deposits of one banking system on to the other. Thus, this study assists the policy makers in determining the role of Islamic banking in the overall economic, fiscal and monetary environment of the country. Introduction The purpose to conduct this study is to examine the level of substitutabil ity in the depository returns under Islamic and conventional banking system. This study comprises on the comparison of the data relating depository returns between the Islamic banking system and the conventional banking system which includes commercial, merchant banks and other financial institutions. Malaysia is considered as a case study in which both Islamic and conventional systems are aimed to be operated on parallel basis by the monetary authorities. In 1983, the first ever Islamic bank that was established in Malaysia was Bank Islam Malaysia Berhad (BIMB). The Islamic banks truly started competition with their conventional counterparts in 1993 when Islamic banking scheme (IMS) was introduced by the Government of Malaysia. This scheme permits the conventional banks to introduce and participate in the products and services initially designed by Islamic banks. By the end of 2002, Total Islamic banking deposits were 10.20% of the countryââ¬â¢s total deposits. Since Malaysian f inancial system is under the sole control of Central Bank of Malaysia, therefore the evidence that there are relationships between TDRs of Islamic and conventional banks and the monetary policy is argued under this study. In case if the there is no substitutability between the rates of depositing and financing in both Islamic and conventional banking systems, then relatively lesser restrictive effects of monetary policy can be observed in this regard. For instance, interest rates are used as a tool by the Central banks to adjust the money supply flowing in the economy. Interest rates are increased or decreased to tighten or loosen the flow of money circulating in the economy respectively. The same phenomenon cannot be established in the Islamic banking system as the depositors are not offered a fixed rate of deposit returns. There is a likelihood that if the required rate of deposit returns on Islamic banking products is not ensured to at least the amount of that conventional bankin g products, the depositors of Islamic banks would switch to other financial instruments of the conventional banks because of fact that the Islamic banking products would be of little use for the monetary purposes. Literature Review The individual saving behaviours are mainly explained by the interest rates offered in the economy as one of the key considerations. The interest rate offerings are considered as a key element because different banks offer different rates of depository returns on varying schemes of deposits. Interest rates are determined mainly because of the concept of time value of money. The longer the time that deposits takes in maturity, the higher will be the yield required by the depositors. For examples, the
Monday, September 23, 2019
Interpreting Financial Results Essay Example | Topics and Well Written Essays - 750 words - 1
Interpreting Financial Results - Essay Example This means that Apple has maintained enough liquid assets to meet its short-term obligation. However, although Apple did well by maintaining a higher current ratio in 2013 compared to 2012, its current ratio declined in 2014 to 1.08 from 1.68 in 2013, which is a sign of poor performance in 2014 compared to 2013 as far as liquidity position is concerned. However, the Apples current ratio is still within the industrial average, which is a show of good performance compared to its competitors in the industry. Apples also had a favorable quick ratio of more than one in all the last three years. However, it is notable that the after the companys quick ratio had improved from 1.30 in 2012 to 1.64 in 2013, the ratio declined to 1.05, which is an indication of poor performance in 2014 compared to the previous two years. However, the fact that Apples quick ratio is within the industrial average is an indication of good performance in overall. Leverage ratio is another ratio used to gauge the financial health of a company. Leverage ratios are used to determine the amount of debts that the company maintains in its statement of financial position. Accordingly, the more debt a company has, the riskier the company is in case the business became bankrupt and forced into liquidation. Debt-to-equity ratio is one of the leverage ratios used to measure the degree to which a company is financed by debt holders in comparison with its owners. The lower the debt-to-equity ratio, the less riskier the company to invest. From the calculations, it emerged that Apple fiancà ©s much of its operations from shareholders investments compared to debts. The companys debt-to-equity ratios for the three years are below one, which is favorable (2014 = 0.13; 2013 = 0.08; 2012 = âËž). Nevertheless, it also became clear that Apple has been increasingly financing its operations by debt since 2013, which is not a good sign (United
Sunday, September 22, 2019
Film Analysis Essay Example | Topics and Well Written Essays - 1750 words - 1
Film Analysis - Essay Example At the conclusion of the discussion, after each technical code has been analysed, a conclusion will be drawn upon to combine each code into one and to dissect these and then to combine them back together to create the overall stylistic expression of the text, which will be considered as 'sombre realism'. The Mise en Scene in the 2002 film The Pianist, works around a realistic perception of stylization which is seen throughout the film. The use of dull colours to emphasize the depressive feeling of the characters is highlighted with their costume, set decoration as well as the buildings around them. The text is set in the early 1940's period of World War II and every part of the mise en scene has been carefully created to conform with this era in order to make it seem realistic. Natural soft lighting is used throughout the text, and it is only used in scenes out of the Jewish Ghetto. For example, an interior scene within the apartment of one of the protagonists' friends who is trying to help him shows very bright natural light to create a binary opposition between the world of the main character, and that of the Polish people who are considered much more contented. This use of three point lighting reflects both worlds in very different ways. Inside the Ghetto, very little lighting is used, and many grey and brown shades of colour are used together with the lack of lighting to create the necessary sensitivity to evoke the emotions of hopelessness and despair. Make up and costume also plays an imperative part in establishing the realism of the text. At the commencement of the film each character is considered well groomed and looking in good health, all with costume consistent with that of the pre-war period. Also, it would be near impossible to tell the difference between a Jew and a Pole. However, as the text progresses, the health and look of the Jewish people living inside the Ghetto decreases, this is made very relevant considering the ways in which they are living. All of this culminates in the end, after the protagonist has made it so far to reach the end of the war, albeit looking much discarded; he manages to borrow a German officer's coat to keep him warm. This proves to be a bad idea when the Polish police begin shooting at him, thinking he is a German. This creates an ironic stylized effect which is unknown throughout the previous sections of the text. As noted before, realism plays a very important part in such a film set in such a time. The acting styles within this text also reflect that fact. A very serious undertone is used throughout, with very little humour to set the sombre undertones that is needed to in effect echo within the text. The use of language code between characters throughout the text is somewhat inconsistent, to also evoke the realism of the time. For example, German officers only speak German throughout the text, whether this is speaking to other officer's or the Jews themselves. The Jew's on the other hand speak English consistently, while speaking German and Hebrew sporadically at certain times throughout the text while communicating with other characters. Cinematography The cinematography in The Pianist is effective in creating the desired depressive war time effects all throughout the film. The camera is efficient in drawing attention to the very small important details that the mise en scene puts out
Saturday, September 21, 2019
Political Issues with the Current Immigration Essay Example for Free
Political Issues with the Current Immigration Essay ââ¬Å"In the wake of the Civil Rights Act of 1964, Congress passed the Immigration Act of 1965. This new law abolished the national origins quota system and barred racial considerations from expressly entering into decisions about immigrant visas; it also imposed for the first time a ceiling (120,000) on migration from the Western Hemisphere.â⬠(Johnson, 2006). Historical Framework for the Issue of Illegal Immigration Towards the end of the 19th century, Congress passed the first immigrant exclusion law restricting criminal and prostitutes, and followed up with the Japanese, Asian and Chinese. Even with this law in place the immigration still reached a record high of 1.3 million personnel in 1907. In 1965, Congress then passed the Immigration and Nationality Act amendments that ended the quota and initiated the concept of family sponsored immigration. In 1987, Congress enacted the Immigration Reform Control Act (IRCA) which authorized two programs to identify and legalize illegal immigrants who are able to document their entry into the U.S. prior to 1 January 1982 (America.gov Archive, 2003). The immigration migration is a phenomenon of crucial importance to the United States as long as the immigration guidelines and procedures are followed, but with the vast number of amendments being reconstructed and enacted by Congress, on almost a daily basis this put additional strain on our border patrol, government agencies, and our military forces who have been tasked to assist in the protection of the U.S./Mexico border alongside the local police officers. On October 1, 2004, Mr. Jim Gilchrist, U.S Vietnam Marine veteran, founded the multi-ethnic Minuteman Project after he had been frustrated dealing with the United States Government to enforce the immigration laws. The Minutemen, who formed the name from militiamen who fought in the American Revolution, has described themselves as ââ¬Å"a citizenââ¬â¢s neighborhood watch on our borderâ⬠,à and have continued to get the media attention on dealing with the illegal immigration issue plaguing the United States. The Minutemen organization has portrayed more of a negative connotation rather than the positive that they had initially strived for. On May 25, 2005 there was the Garden Grove Incident dealing with protestors. On October 4, 2006 they had the Columbia University incident where their stage was stormed by student protestors. The T-Shirt incident on April 6, 2005 in which minutemen had an old man poses with a racial discrimination T-shirt, and in August 2007 there was a fake murder video published by the organization (Sanchez, 2011). Even with this negativity, on April 28, 2005, California governor Arnold Schwarzenegger praised the Minutemen Project on a Los Angeles radio station KFI. The issues of the constant illegal immigration border crossings, violence and murders on the borders of the immigrants and law enforcements officers, the immigration laws will continue to be pushed through Congress in order to keep our borders safe and ensure the diverse cultures visiting the United States are entering with the appropriate documentation instead of through the desert with a backpack, bottles of water, and for some, with bags of drugs. Is the Media Portrayal of biased or unbiased Illegal Immigration? On October 6, 2010, Janet Napolitano, Secretary of the Department of Homeland Security, announced that record numbers of deportations of criminal aliens, declaring that these figures have demonstrated that President Obamaââ¬â¢s administration is focused on enforcing our immigration laws that prioritizes public safety a nd national security. One of the political issues on July 7, 2011, according to Treasury Inspector General for Tax Administration (2011), a memorandum was published entitled ââ¬Å"Individuals Who Are Not Authorized to Work in the United States Were Paid $4.2 Billion in Refundable Creditsâ⬠which is also the entire product of the Additional Child Tax Credit (ACTC) for the 2010 tax processing year (Impact on Taxpayers). Illegal immigration laws that are in place are not only bottlenecking the system, becoming costly to taxpayers and increasing the deficit, but the ranchers along the border are either having the illegals trespassing onto their land, destroying their fence line along the property, and on a few occasions ranchers have been killed. Mr. John Ladd, a rancher on the Southern border of Arizona, has a ranch sprawling over 14,000 acres between Mexico border and state highway 92. His ranch is the major corridorà for the smuggling of drugs and human beings into the United States. The border pat rol makes frequent arrests on the ranch, but most of those are released back into Mexico where they regroup and try again until they are successful (Gisorg, 2010). On average, one mile of border fence costs US taxpayers $4 million. Is it worth the expense? The measurements of this fence is 21 feet (6.4m) tall and 6 feet (1.8m) embedded into the ground, and cemented in a 3 foot (.91m) wide trench. With all of this material, manpower, monetary cost and security, on December 16, 2010, a video was shot showing two young American students visiting the border and on their first try, these girls made it to the top of the fence in less than eighteen seconds. How much time do you think it will take if you visit the beach of Tijuana and just swim out to the fence line and cross over? Does the publicââ¬â¢s perception encourage or discourage prejudice, labeling or stereotyping? There are media commentaries that intentionally sensationalize the story being reported; it all depends on where their station ratings stand. Even unintentional biased reporting can be portrayed depending on what the listenerââ¬â¢s views are on immigration. I cannot justify what their true intentions are, but as a viewer there are times when my perception is that they are not telling the full story, or the story is biased to the side of the populace majority. One of the best media outlets Iââ¬â¢ve come across depicting the conflict between bordering countries was by the Coca-Cola Corporation. Two guards who are patrolling their border, walking back and forth along a stretch of about 15 feet with hatred and discontent showing on their faces not uttering a word. What brought these two cultures to a brief truce was a 16oz bottle of Coca-Cola (Gisorg, 2010). Even In the portrayal of the movie ââ¬ËBordersââ¬â¢ which depict the immigration issues with Mexico and the United States. Chris Burgards award winning television series takes an impartial look at the agonizing and complex issue of our southern U.S. border. This film fosters debate, open discussion, and hopefully a more balanced outlook towards a national problem that has polarized our nation.â⬠(Rick Dixon, Star Tribune, 2011). During the viewing, you may perceive that all Hispanics are probably in this country illegally, drug runners or coyotes. This actually encourages hatred of most Hispanics because they are perceived the same as terrorist in this land. This show demonstrates how individuals should be fighting again crime and illegal immigration of allà types, and the question you should be asking yourself is if you believe in your government, and what is the true border between justice and crime. Does this issue affect the U.S. economy and labor force? Presently illegal immigrants arriving into country are taking advantage of the job workforce that average Americans deem beneath them. They are willing to take on those jobs that we perceive as demeaning, and underpaid. Due to this immigration issue, the United States, as paid over $4.2 billion dollars towards labor for the illegal immigrants and over $100 billion each year on medical, housing and education. According to the Arizona state treasurer Dean Martin, they are losing between $1.3 and $2.5 billion each year on illegal immigrant on incarceration, education and their families. This does not account for the legal services that are provided through the court system. As a manager, what inclusion strategies would be implemented? When dealing with the issues of illegal immigration and the media coverage as a manager, there are strategies that can be utilized to foster a collaborative working environment for employees. Coordinate with Human Resources to schedule diversity and equal opportunity training, plan a quarterly cultural luncheon/potluck, and during each holiday ensure there are decorations representing every culture in your organization and allow those individuals to explain what each trinket means. When dealing with stereotyping, encourage employees to ask questions concerning that cultural difference they donââ¬â¢t understand or have perceptions about. Most organizations will have a media device placed in the office, and employees will hear of negative connotations dealing with the diverse groups around the United States. If listening to these stories makes you stop and think, then it will also make you wonder about that culture. Not all individuals in are the same, and not all cultures are radical, illegal immigrants or a threat. Conclusion The media is the media is the media. As long as there is conflict it will be reported to the masses. Illegal immigrants and immigration laws are tied to the hip and will always be part of society and culture. Unless the United takes a lesson from the 1981 television show called ââ¬ËEscape from New Yorkââ¬â¢,à produced by John Carpenter, place a twenty-five foot solid cement wall that is fifteen feet thick around the state. There will always be illegal immigrants either from Mexico, Cuba, and other countries seeking domicile in the United States. References America.gov Archive. (2003). The Immigration Act of 1965. Retrieved from http://www.america.gov/st/educ-english/2008/April/20080423214226eaifas0.9637982.html Canoy, M., Beutin, R., Horath, A., Hubert, A., Lerais, F., Smith, P., Sochacki, M. (2006, September 10). Migration and public perception. Retrieved from http://ec.europa.eu/dgs/policy_advisers/publications/docs/bepa_migration_final_09_10_006_en.pdf Gemano, R. P. (2010, December 16). 2 Girls Undermine US Border Strategy in Under 18 Seconds [Video file]. Retrieved from YouTube website: http://www.youtube.com/watch?v=XHjKBjM1ngwfeature=related Gisorg. (2010, August 9). Gaming the Border: A Report from Cochise County, Arizona [Video file]. Retrieved from YouTube website: http://www.youtube.com/watch?v=iRof_dizXH4 Johnson, K. R. (2006). The History of Racial Exclusion in the US Immigration Laws. Retrieved from http://academic.udayton.edu/race/02rights/immigr09.htm Morgenstern, M. (2011). TheBlaze. Retrieved from http://www.theblaze. com/stories/govt-audit-illegal-immigrants-received-4-2-billion-in-tax-credits-last-year/ Pemberton, J. S. (2011, February 3). Coca-Cola Border [Video file]. Retrieved from YouTube website: http://www.youtube.com/watch?v=k-STkFCCrus Sanchez, C. (2011). HATEWATCH. Retrieved from http://www.splcenter.org/blog/2007/08/13/new-video-appears-to-show-vigilante-border-murder/ Treasury Inspector General for Tax Administration. (2011). Individuals Who Are Not Authorized to Work in the United States Were Paid $4.2 Billion in Refundable Credits. Retrieved from http://Individuals Who Are Not Authorized to Work in the United States Were Paid $4.2 Billion in Refundable Credits
Friday, September 20, 2019
Mechanisms of Adsorption of Aormatic Nitrogen Compounds
Mechanisms of Adsorption of Aormatic Nitrogen Compounds MECHANISMS OF ADSORPTION OF AORMATIC NITROGEN COMPOUNDS AND AROMATIC COMPOUNDS ON METAL-ORGANIC FRAMEWORKS (MOFs) by JUN DAI Metal-Organic Frameworks (MOFs) constitute a class of novel porous materials which have attracted significant interest due to their application in separation, storage, catalyst and sensing. Large surface area and porous cavity make MOFs excellent absorbents with huge uptake capacity. In this paper, we studied adsorption mechanisms of adsorption of indole and naphthalene on Basolite F300, Basolite A100 and MIL-100 (Fe) by two complementary spectroscopic methods. Fluorescence spectroscopy and near-UV/Visible diffuse reflectance spectroscopy study demonstrate that naphthalene is quantum confined within the mesoporous cavity in F300. On the other hand, indole is weakly electronically bound to Fe (III) CUS in F300 and forms adsorption complex with F300. Direct spectroscopic proof of adsorption complex is provided by near-UV/Visible spectroscopy and fluorescence spectroscopy. Quenching of ligand-based fluorescence of A100 by indole is suggested and we propose adsorption of indole and napht halene onto A100 via Ãâ¬-Ã⬠interaction, spectroscopic proof is provided by fluorescence spectroscopy.à Table of Contents Title Abstract Acknowledgements and Dedication Table of Contents 1 Introduction 1.1 Metal Organic Frameworks (MOFs) 1.2 Clean Fossil Fuels 1.3 Nitrogen Aromatic Compounds in Fossil fuels 1.4 Aromatic Compounds in Fossil Fuels 1.5 Methods of Denitrogenation 1.5.1 Microbial Denitrogenation 1.5.2 Hydrodenigrogenation (HDN) 1.5.3 Adsorptive Denitrogenation (ADN) 1.6 Activation of Open Metal Sites of Metal-Organic Frameworks 1.7 Adsorption of Aromatic Compounds and Aromatic N-heterocyclic Compounds on mesoporous MOFs with CUS: MIL-100 (Fe) and F300 1.8 Adsorption of Aromatic Compounds and Aromatic N-heterocyclic compounds on microporous MOFs without CUS: MIL-53 and A100 1.9 Research Objective 2 Experimental 2.1 Metal Organic Frameworks 2.2 Solvents, Aromatic compounds and N-containing compounds 2.3 Activation and Hydration of Metal-organic frameworks 2.4 Fluorescence Spectroscopy 2.5 Near UV-Vis Diffuse Reflectance Spectroscopy (near UV-Vis DRS) 2.6 Model Fuels 2.7 Solid Mixture of Aromatic and Aromatic N-hetrocyclic compounds with MOFs 2.8 Stoichiometric adsorption complex of F300 and naphthalene in eicosane matrix 2.9 Kinetic adsorption of liquid indole on Basolite F300 (FeBTC) in liquid phase 2.10 Stoichiometric adsorption complexes of indole/naphthalene with MOFs 2.11 UV radiation 3 Results 3.1 Spectroscopic Studies of adsorption of naphthalene and indole on mesoporous F300 and MIL-100 (Fe) with CUS 3.1.1 Solid Mixtures of MOFs and organic aromatic compounds 3.1.2 Fluorescence spectrum of pure naphthalene List of Figures Figure 1: Structure of MIL-100 (Fe) (see as S1 in supplementary) Figure 2: Structure of MIL-53 (Al) (see as S2 in supplementary) Figure 3: Common nitrogen compounds existing in fossil fuels Figure 4: Pathways for the transformation of quinoline Figure 5: Fluorescence spectrum of (A) 0.08 M liquid solution of naphthalene (NAP) in n-heptane, à »exc = 280 nm, bandwidth: Exc. Slit 5 nm/Emi. Slit 5nm. (B) 0.08 M liquid solution of NAP in n-heptane with multi-Gaussian curve fitting Figure 6: Fluorescence spectrum of (A) pure naphthalene (NAP) à »exc = 280 nm, bandwidth: Exc. Slit 5 nm/Emi. Slit 5nm (B) pure NAP with multi-Gaussian curve fitting List of Tables Table 1: MOFs used in this research and structure information Table 2: Physical property of common nitrogen aromatic compounds existing in fossil fuels 1 Introduction 1.1 Metal Organic Frameworks (MOFs) Porous materials are well studied and widely used in science and engineering industry. Recently, a novel kind of porous material ââ¬ËMetal-Organic Frameworks (MOFs)ââ¬â¢ has emerged as potential competitor. MOFs are crystalline hybrid inorganic-organic porous solid formed by chemical metal-linker bounding1. Metal-Organic Frameworks (MOFs) constitute a class of novel porous materials which have attracted significant interest due to their application in separation, storage, catalyst and sensing. The use of MOF as stationary phase in high resolution GC separation of aromatic hydrocarbons has also gained significant attention2. In comparison with adsorption on the MOFs in gas phase which has been well studied and understood, adsorption on the MOFs in liquid phase is much less known. MOFs have extremely large surface area and porous cavity, which make them excellent adsorbents with huge uptake capacity. As a class of coordination compound repeated by metal or metal clusters as SBUs (second building units) and organic linkers, the cavity ranged between that of Zeolite and mesoporous silica3. Regarding the structures, variety of MOFs can display either 2 dimensional or 3 dimensional structures depend on different organic linkers. It is also indicated by J. R. Karra and K. S. Walton that the relation between pore size and guest molecule size plays an essential role in the adsorption4. The MOFs being investigated in this research are mesoporous and microporous MOFs. For mesoporous MOFs the pore size can vary from 2 nm to 50 nm, while for microporous MOFs the pore size is less than 2nm. Pore size can be a key in adsorption on MOFs due to micropore filling mechanism2, which suggests adsorption capacity depends on molecular cross-sectional area rather than minimum diameter. MOFs are structurally stable under ambient environment. It is reported by many authors that MOFs remain stable under increased temperature and under oxygen. In this research, our investigation mos tly focuses on several common MOFS, and their commercial names are Basolite C300, Basolite F300, Basolite A100 and MIL-100 (Fe) (MIL=Materials of Institute Lavoisier). All Basolite C300, Basolite F300 and Basolite A100 are bought commercially, and MIL-100 (Fe) is made with the collaboration of Dr. Jing Li from Rutgers ââ¬â New Brunswick. Table 1 shows the basic physical information of the MOFs used in this research. Table 1: MOFs used in this research and structure information MOFs/formula Surface area/m2g-1 Pore dimension/Ã⦠Pore dimension Ref. BET Basolite F300 1300~1600 21.7 3D Sigma-Aldrich,5 Basolite A100 1100~1500 7.37.7 1D Sigma-Aldrich, MIL-100 (Fe) 2200 25, 29 3D 5 MIL-100 family MIL-100(M) (M=Cr, Fe, Al) refers to a family of mesoporous Metal-Organic Frameworks built up from metal clusters and benzene-1, 3, 5-tricarboxylic (BTC) linkers. These MOFs possess large surface area and have recently attracted tremendous attention for applications in adsorption and separation due to the coordinated unsaturated sites (CUS) which can provide chance for Lewis acid-base interaction between guest molecules and metal ions or metal clusters. In Metal-organic frameworks, metal sites (SBUs) are coordinated with organic linkers. Open metal sites (CUS) may be available on these SBUs. CUS are very important in gas storage, separation, sensing, catalysts, and even biological systems6. Considerable amount of research on the adsorption of small molecules have been done recently. Evidence has shown open metal sites have essential influence on adsorption property in MOFs. It is reported that open Cu2+ metal sites in HKUST-1 contribute significantly to the high acetylene storage capa city7. Moreover, MOFs with CUS such as HKUST-1 are used in chromatography separation due to its specific feature to distinguish strongly and weakly electron donating analytes8. In additional, MIL-100 (Fe3+, Cr3+, Al3+) has been shown to have strong preference to adsorb N-heterocyclic compounds (Lewis base) in mixtures910. Hence, open metal sites can be potential Lewis acid sites, the possible interactions between guest molecules and open metal sites will be examined and discussed in this paper. In our research, MIL-100 (Fe) will be used to investigate the adsorption mechanisms between guest molecules such as indole or naphthalene and sorbent MOFs. Besides MIL-100, there is a commercially made MOF named Basolite F300, which has a similar chemical composition. Both Basolite F300 and MIL-100 (Fe) are built up by Iron and BTC linkers. However, due to the poor crystallinity, the actual structure of F300 is still not known at this time. Difference in iron content and carbon content in F300 and MIL-100 (Fe) is shown by D. Amarajothi and his co-workers5. The iron mass content in F300 and MIL-100 (Fe) are respectively 25% and 21%. The carbon mass content in F300 and MIL-100 (Fe) are respectively 32% and 29%. Pore dimension in F300 and MIL-100 (Fe) are respectively 21.7 Ã⦠and 25/29 Ãâ¦. Structure of MIL-100 (Fe) is shown below: Figure 1: Structure of MIL-100 (Fe) (see as S1 in supplementary) MIL-53 family There are many types of MOFs that undergo hydrolysis, while there are other MOFs that remain stable within water. Water stable MOFs start to showing potential applications in drug delivery and imaging11. Many MOFs containing Al as metal sites and amino acids as organic linkers are stable in aqueous solution, and it is also possible to synthesize them in aqueous environment12. MIL-53(M) (M= metal as Al13, Cr14, Fe15, In16, Sc17) is a common family of microporous MOFs and has excellent water stability. Figure 2: Structure of MIL-53 (Al) (see as S2 in supplementary) The one dimensional pore structure of MIL-53(Al) is built by chains of corner-sharing octahedra aluminum clusters AlO4(OH)2 and anion form of benzene-1,4-dicarboxylic acid (BDC) as organic linkers connecting infinite numbers of metal clusters. MIL-53 (Al) has rhombic channels which have dimension of 7.3 x 7.7 Ãâ¦. A huge Langmuir surface area of 1600 m2/g makes MIL-53 (Al) an efficient adsorbent. MIL-53 (Al) has extraordinary thermal stability up to 773 K. It is believed that the structure of MIL-53 (Al) undergoes a reversible structural change during process of adsorbing/desorbing water molecules, and is described as ââ¬Ëbreathingââ¬â¢13. The so-called ââ¬Ëbreathingââ¬â¢ process interchanges between large-pore (lp) form (Al(OH)[O2C-C6H4-CO2]) and narrow-pore (np) form (Al(OH)[O2C-C6H4-CO2]H2O) 13. The lp form has a dimension of 8.5 x 8.5 Ã⦠and is obtained when activated upon high temperature and under high vacuum, which takes away excess free BDC acids, oxygen and water trapped in the cavity during synthesis. The lp form is capable of adsorbing water molecules in vapor at room temperature, as a result, the MIL-53 (Al) shifts to itsââ¬â¢ np form. As shown in the formula, the np form contains one trapped water molecule every unit or cavity. Hydrogen bonds are found to form between carboxylic groups on the linkers and adsorbed water molecules. Due to this ââ¬Ëbreathingââ¬â¢ feature, applications on selective adsorption of various compounds in gas phase have already gained interest and being reported14. The np form of hydrated MIL-53 (Cr) is able to selectively adsorb CO2 in presence of CH4 in gas phase. Upon adsorption of CO2 but not CH4, MIL-53 (Cr) returns to its lp form with an increased cavity volume of 1522.5 Ãâ¦3 from np volume of 1012.8 Ãâ¦3. In our research, we used Basolite A100 MOF from the BASF, which is commercially available and is equivalent to MIL-53 (Al). Similarly, A100 is build up with AlO4(OH)2 octahedral clusters connecting by BDC linkers, and gives a surface area of 1084 m2/g and pore volume of 0.51 cm3/g as determined by N2 physical-adsorption at 77 K. Additionally, XRD pattern of A100 is proved to resemble that of MIL-53 (Al)18. G. Blanco-Brieva and his co-workers have studied adsorptive removal of aromatic sulfur compounds from model liquid fuels on thermally activated A10019. 1.2 Clean Fossil Fuels Combustion of sulfur and nitrogen containing compounds in fossil fuels will bring adverse effect to public health, environment and economy. It is widely recognized that nitrogen compounds are normally carcinogenic and mutagenic. Separation of heterocyclic compounds from petro-chemical feedstock has become an urgent application leading to clean liquid fossil fuels. Fossil fuel is a primary source of energy on the earth, the intensive use of fossil fuels has raised environmental concerns. Beginning in 2006, the Environmental Protection Agency (EPA) began an ambitious program aiming to reduce the sulfur content of diesel fuels. As of July 11, 2010, the EPA required that the concentration of sulfur content in diesel fuels not exceed 15 ppm20. For certain ultra-clean gasoline, diesel fuels and jet fuels, sulfur level needs to be lower than 1 ppm21. Hydrodesulfurization (HDS) of diesel fuel has become an essential research interest, while the presence of nitrogen compounds in middle-distil late oil inhibits the ultra-deep hydrodesulfurization22232425. In HDS, sulfur compounds are hydrogenated to hydrocarbons and H2S over catalyst such as Zeolites9. However, the nitrogen aromatic compounds in crude oil are found to compete for the active sites on these catalysts to inhibit a deep HDS26,27. This gives rise to the necessity for denitrogenation in fossil fuels. Moreover, the combustion of nitrogen compounds in petroleum leads to the formation of NOx oxides, which is a group of highly reactive and persistent species and contributes directly to acid rain and greenhouse effect. The life time of NOx oxides in atmosphere is 120 years before being removed or destroyed through chemical reactions. The impact of 1 pound of NOà x on warming the atmosphere is over 300 times that of 1 pound of carbon dioxide. EPA first set standards for NO2 in 1971, setting both a primary standard (to protect health) and a secondary standard (to protect the public welfare) at 0.053 parts per million (53 ppb), averaged annually28. Also the presence of nitrogen aromatic compounds in fossil fuels can lead to poisoning of refining catalyst, which will eventually cause a decrease in yield. Thus, denitrogenation is necessary for deep desulfurization and has drawn significant interest around the world due to the increasingly rigid regulations and fuel specifications in many countries. 1.3 Nitrogen Aromatic Compounds in Fossil fuels Fossil fuels are naturally-formed fuel that contains significant level of heterocyclic aromatic contaminants. There are some representative sulfur aromatic compounds such as benzothiophene (BT) and dibenzothiophene (DBT), representative nitrogen aromatic compounds such as indole and quinoline. Nitrogen aromatic compounds content in crude oil averages around 0.3%. Although the concentration of nitrogen compounds in crude oil is relatively low, the concentration turns out to be higher throughout the petroleum distillation process. Common nitrogen aromatic compounds in fossil fuels are shown in Figure 1.129 and physical properties of nitrogen aromatic compounds investigated in this research is shown in Table 2. Nitrogen aromatic compounds in fossil fuels fall into two classes. One is non-basic nitrogen compounds including indole and pyrrole due to the fact that the extra pair of electrons on N is contributed to the Ã⬠electron cloud and is not available for interaction with acids. While the other class is basic nitrogen compounds such as pyridine, quinoline and their derivatives, in which the lone pair of electrons on N is available as an electron donor. Indole is one of the most common nitrogen compounds in fossil fuels, and it has been broadly studied. And we choose indole in our research due to the fact that indole is a weakly basic N-containing compound, which means it has a potential of selective adsorption against aromatic compounds and desorption is possible and reasonably convenient. Figure 3: Common nitrogen compounds existing in fossil fuels Table 2: Physical property of common nitrogen aromatic compounds existing in fossil fuels Compounds Formula Melting Point, ÃÅ'Ã
C Density, g/cm3 Dipole moment, D Acidity,pKa Maximum diameter, ÃÅ'Ã
A Indole C8H7N 52~54 1.17 2.11 16.2 6.9 Quinoline C9H7N -15 1.093 0 4.85 7.2 Isoquinoline C9H7N 26~28 1.099 0 5.14 7.2 1.4 Aromatic Compounds in Fossil Fuels Fossil fuels contain significant amount of hydrocarbons, most of them are aromatic compounds and polycyclic aromatic hydrocarbons (PAHs). In this research we choose naphthalene as representative aromatic compounds, and in order to investigate the adsorption mechanism we use fluorescence spectroscopy and UV-Vis diffuse reflectance spectroscopy to investigate electronic interactions upon adsorption onto MOFs. Naphthalene is the most simple and common aromatic compounds in PAHs. And naphthalene is commonly produced in petroleum refining and is then separated from the petroleum. Purification and separation of these aromatic rings is of interest in chemical industry. Naphthalene has a molecular length of 7.2 Ã⦠(largest diameter determined by ChemDraw 3D) and is non-polar. 1.5 Methods of Denitrogenation Microbial Denitrogenation Microbial process is an alternative pathway for denitrogenation. Microorganisms are known to consume natural organic compounds and convert them into carbons and energy, and they are capable of metabolizing certain molecules including nitrogen compounds from fossil fuels. The degradation of quinoline is well-characterized, and the transformation pathways are elucidated by M. Benedik et al29 (shown in Figure 1. 5). The degradation of isoquinoline is less understood but 1-oxo-1,2-dihydroisoquinoline is suggested as initial oxygenated product30. According to the finding of Claus, G, indole is readily degraded via catechol or transformed directly into tryptophan30, while carbazole is relatively more difficult to be degraded. One possible degradation pathway31 beginning with angular dioxygenation has been proposed by Ouchiyama, N., which finally enters TCA cycle after conversion to catechol or tryptophan32. Mechanisms for the degradation of other nitrogen compounds such as pyridine, quinol ine, acridine and their derivatives are reviewed in detail by J. Kaiser33. Recent research in microbial denitrogenation has revealed a promising future for application in selective removal of nitrogen- and sulfur-containing petroleum. However, as a major mechanism for the removal and metabolism of organic compounds from the environment, itsââ¬â¢ characterization of the enzymes involving in the pathways is still under research29. And it has not been widely applied to the industry yet. Figure 4: Pathways for the transformation of quinoline Hydrodenigrogenation (HDN) Hydrodenitrogenation (HDN) is usually used to remove nitrogen compounds in fossil fuels during the refinery process, and Co-Mo catalyst is normally involved in the process. However, the HDS process is accomplished by reacting with hydrogen at high temperature and high pressure. It is energy-intensive, hazardous and costly. Thus, significant amount of researches have been done on HDN in order to reach a goal of being economic and environmentally friendly. Adsorptive Denitrogenation (ADN) Another promising way to selectively remove the nitrogen compounds in fossil fuels is adsorption on a porous material, Activated carbon34353637, Zeolites38, HCL-loaded silica-aluminas39, ion-exchange resins40, meso-silicas41,42, Ti-HMSs43, microporous carbon44, activated aluminas45, Ni-based adsorbents45, and NiMOs46 have been used for ADN. While recently the use of MOF adsorbents has gained significant interest in adsorption and separation of aromatic and heterocyclic compounds in liquid phase due to itsââ¬â¢ high capacity, high selectivity, economic importance and most importantly energy saving 47. Moreover, MOFs can even be recycled and effectively reduce the cost. Adsorptive separation via ââ¬Å"adsorptive denitrogenation (AND)â⬠is preferred over industrial catalytic HDN10. Specifically, selective adsorption of N-heterocyclic compounds48 in presence of aromatic and aliphatic hydrocarbons in liquid phase49 is of interest, which is investigated in this research. 1.6 Activation of Open Metal Sites of Metal-Organic Frameworks Available CUS in MOFs is essential for the adsorption of Lewis basic compounds. Thus, to fully utilize the open metal sites in MOFs, activation is needed to evacuate the water molecules which are relatively weakly coordinated on these metals. Because MOFs are strongly adsorptive molecules, humidity can be crucial to the availability of open metal sites in MOFs. Specific treatment is necessary at certain temperature under vacuum in order to activate open metal sites. And protection of the sample against humidity is critical during experiments. Interestingly, it is discovered by K. Schlichte and his colleagues that upon activation the color of HKUST-1 would change from light cyan to dark navy50. This is confirmed by E. Borfecchia and his working group using UV-Vis, a red shift at LMCT edge and appearance of a shoulder in d-d band at around 600 nm in UV-Vis spectrum is observed and explained by the removal of water51. In addition to the activation of MOFs, partial reduction of MIL-100 (Fe) has been reported by H. Leclerc and his group52. Certain metal sites in MOF can be reduced, for example, Fe3+ in MIL-100 (Fe) can be reduced to Fe2+. According to their analysis of oxidation states via IR, outgassing at 423 K for 12 hour will give rise to a greater proportion of Fe2+ sites while minority of Fe3+ sites is reduced. However, outgassing at 523 K will result in that most Fe3+ sites are reduced. Fe3+ sites are more Lewis acidic sites than Fe2+, it is easier for Fe3+ to form coordination bond with nitrogen aromatics, which are good Lewis base. 1.7 Adsorption of Aromatic Compounds and Aromatic N-heterocyclic Compounds on mesoporous MOFs with CUS: MIL-100 (Fe) and F300 Although adsorption of small organic molecules on MOFs both in liquid phase and in vapor, such as toluene, benzene, xylene isomers2, etc., has been well studied in the recent years, to our knowledge the adsorption of fuse-ring aromatic hydrocarbons on MIL-100 in liquid phase has not been reported. M. Maes and his co-workers have reported adsorption of indole from heptane/toluene mixture solution on MIL-100 family9. Thus, mechanism of adsorption of aromatic compounds versus aromatic N-heterocyclic compounds on F300 has not been studied. According to many studies, the formation of complexes in liquid adsorption is usually assumed, but there is a lack of direct spectroscopic evidence. Adsorption of small aromatic ring compounds (benzene and p-xylene molecules) on MIL-101 has been published by K. Yang, et al2. Pore-size filling mechanism is discovered and discussed in this paper, indicating that pore-size and different substrate relates with molecular selectivity of organic compounds. Ho wever, the mechanism is still not understood. Fluorescence spectroscopy is a straightforward method for studying the adsorption mechanism between guest molecules and MOFs. Yet there are rarely papers studying characterization of adsorption of aromatic compounds in liquid or solid system by fluorescence spectroscopy. It is assumed based on fluorescence spectra that Lewis acid-base interaction promotes the adsorption of pyrene on Al2O3 from model fuel using octane as solvent53. While the fluorescence spectra was collected using a model sorbent aluminum chloride in methanol instead of actual Al2O3 in model fuel, spectroscopic characterization of adsorption complexes formed by MOFs and aromatic compounds or aromatic N-heterocyclic compounds by the fluorescence spectroscopy is still unknown to our knowledge. Another useful characterization method is near-UV/visible diffuse reflectance spectroscopy (DRS), which is excellent at detecting the variation or shift in electronic states on adsorption complexes forming by metal sites and guest molecules. The DRS was used to identify the interactions between aromatic amines and MOFs54 but it has not been used to explore the interactions between metal sites of MOFs and guest molecules as aromatic compounds or aromatic N-heterocyclic compounds. Thus, we aim to investigate the adsorption of large aromatic compounds on MOFs using two spectroscopic methods as fluorescence spectroscopy and near-UV/visible diffuse reflectance spectroscopy. 1.8 Adsorption of Aromatic Compounds and Aromatic N-heterocyclic compounds on microporous MOFs without CUS: MIL-53 and A100 M. Maes and his colleagues have studied the adsorption of indole and methyl-substituted indole present in model fuel (heptane/toluene at either 80 vol. %/20 vol. % or 20 vol. %/80 vol. % combination) at initial concentration of 0.15 M on thermally activated MIL-53 (Al)9. The amount of absorbed indole intensively dropped in model fuel with toluene, which indicates a possible competitive adsorption. While no data of adsorption capacity for indole and substituted indole on MIL-53 (Al) in n-alkane solvent was reported, not enough experimental evidence or computational evidence can be used to prove the mechanism of competitive adsorption. Similarly, adsorption of indole, pyridine, pyrrole and quinolone on thermally activated MIL-53 (Al) has been studied in another paper. In this paper n-octane was used as solvent, however, no data for adsorption capacity of indole on MIL-53 (Al) has been reported55. Ãâ¬-Ã⬠interactions is suggested to be the major force that introduce the adsorption of indole or quinolone onto activated MIL-53 (Al), but no experimental evidence was given55. At the present time, no direct spectroscopic characterization of chemical bonds between aromatic or hetero-aromatic adsorbate and MIL-53 has yet been reported. Furthermore, adsorption of naphthalene on MOFs has not been reported to our knowledge. To investigate the adsorption mechanisms through fluorescence spectroscopy, it is essential to know the origin of the fluorescence from MOF itselft. It was discussed in a review paper by M. Allendorf, C. Bauer, R. Bhakta et al.56, that there are five modes for generating fluorescence in MOFs: linker-based, framework metal ions (charge transfer between linker and metal), adsorb
Subscribe to:
Posts (Atom)