Synthesis of Polyelectrolyte Pani Membrane

Synthesis of Polyelectrolyte Pani Membrane SYNTHESIS OF POLYELECTROLYTE PAni MEMBRANE BYÂ  PHASE INVERSION AND ITS CHARACTERIZATIONS NURUL IZZATI IZNI BT MAT YUSOFF INTRODUCTION During the last few decades, the application of membrane based separation is the leading technology as one of the alternatives used in separating and removal of organic solvents. Moreover, it holds a significant commercial impact in several areas including water and wastewater treatment, chemical, food industries, pharmaceuticals, petrochemical related industries and bioseparation areas (Javed Alam et al., 2012). However, membrane-based separation processes are comparatively new in the field of separation which makes current membranes have limitations that hinder their wide used in aggressive solvents. The situation has led many studies in order to develop this membrane-based technology. Amongst the new generation of intrinsically conducting polymer, polyaniline (PAni) membranes have captured the intense attention of scientific community and one of the promising candidates. PAni is a polymer which poorly soluble in almost all solvents and has been widely known due to its conductive properties. Most important, it is easy to synthesize this polymer and it has an interesting doping and dedoping characteristics. However, the high yield of PAni demands several essential conditions. In order to obtain a higher quality polymer product, highly pured monomers, chemicals and solvents are needed. Besides, a strict control on polymerization conditions are needed since the small variation in the polymerization conditions might alter the nature of the product (Sadia Ameen et al., 2011). From the previous study, there are many research have been done in order to produce a stable and useful PAni membrane in nanofiltration. Most of the researches focused on synthesize, membrane fabrication and doping/dedoping of PAni membrane. However, the study on PAni membrane can be expand more instead of those previous research. The stability and performance of PAni membrane on polyelectrolyte coating should be done to further this study. Polyelectrolyte is a macromolecular species that upon being placed in water or any other ionizing solvent dissociates into a highly charged polymeric molecule (Reza Derakhshandeh et al., 2010). One of the methods of polyelectrolyte coating is layer by layer (LBL) coating. LBL is the simplest process being used by most of the researcher. There are numerous advantages of this method compared to other methods for thin film fabrication. The unique advantages of the method are that, both organic and inorganic can be incorporated into LBL thin films bes ides offers easier preparation and durable (unknown, yr). PROBLEM STATEMENTS There are numerous number of membranes have been develop by researchers. However, membranes nowadays have fixed physical-chemical properties which make separation by membranes very limited to the fixed selectivity of their constituent. Therefore, new membrane materials must be explored to cope with these limiting factors. Next generation of filtration membranes must be more selective and robust which requires low chemical and energy input (Sajjad Sedaghat, 2014). These properties must be considered to meet goals in applications since current membranes often problematic in cost. Membranes basically can be prepared from ceramic and polymeric materials. There are many studies shown that ceramic materials have several advantages over polymeric materials. As example, membrane from ceramic materials is highly stable in terms of chemical and thermal stability. Unfortunately, the market share of polymeric membranes is far greater than ceramic membranes as the polymeric materials are easier to process and less expensive (Khulbe et al., 2008). Instead of those materials, there are also membranes from inorganic materials that have been successfully applied in dehydration of tetrahydrofuran (THF). However, to produce an inorganic membrane requires a high cost rather than polymeric membrane beside their system design is more complex (Chapman et al., 2007). Therefore, membrane from polymeric material is a suitable candidate for the research since it meets the desired criteria. PAni as a polymeric material has been widely researched due to its conductive properties. To date, although PAni has been applied to a number of applications but there are still some deficiency. For instance, PAni membranes which applied to chemically crosslinked swell in THF although it retained their structure while too much thermal crosslinking gave membranes with no fluxes in any solvents at all. Furthermore, unsupported PAni membranes shrank during the process of thermal crosslinking which causing some trouble for large scale membrane productions where certain amount of bending or curling is required (Loh et al., 2008). An alternative to thermal or chemical crosslinking would be polyelectrolyte coating to make them more stable. OBJECTIVES The objectives of this study are: To produce phase inversion PAni membrane from chemical polymerization of PAni in APS solution. To introduce polyelectrolyte onto the synthesized membrane. To characterize the membrane morphological, physical, chemical, electrical and filtration properties. LITERATURE REVIEW METHODOLOGY Chemicals All chemicals and reagents will be used are analytical grade. AnalaR aniline, ammonium persulfate (APS), N-methyl-2-pyrrolidone (NMP), 4-methylpiperidine (4MP), poly(acrylic acid) (PAA) poly(allylamine hydrochloric) (PAH), hydrochloride acid (HCL) and lithium chloride (LiCl) PAni synthesis by chemical polymerization To produce an Aniline solution, 37.25 g of 0.4 mol Aniline will be added into a beaker containing 400 mL of 1.0 M HCl. The mixture is well mix. In another beaker, APS solution will be prepared by adding 91.26 g of 0.4 mol APS into 256 mL of 1.0 M HCL. To prevent the mixture from freezing at -15 oC, add 66.8 g and 39.68 g of LiCl into both beakers respectively. After finish the preparation of both solutions, mix them in a conical flask. The conical flask then will be put in an incubator shaker at temperature -15 oC and continuously shake for 48 h. During this period, a reaction occur which polymer filter cake will be produced. After 48 h, filter and wash with 1.5 L DI water to remove any left-over reactants. To deprotonate the emaraldine salt to its base form, the filter cake then is being place in a beaker contain 250 mL ammonia solution (33% w/v) in a beaker and will be mix by using incubator shaker for 12 h at room temperature. Next, the filter cake will be filter and will be wash with 1 L DI water. To remove any low weight PAni oligomers and decrease time drying, the filter cake will be wash again with 500 mL methanol before being dry under vacuum for 24 h. After drying, the dry Emeralidine Base (EB) powder will be pass through a 160 Â µm mesh sieve to remove remaining clusters. Then, the EB powder will be stored under argon at 4 oC until required (Chapman et al., 2007). Membrane production by phase inversion PAni membrane will be produce by wet phase inversion method. First of all, 4MP and NMP will be mix in a beaker to make up the solvent. Then EB powder will be add using a funnel and mix at speed 300 rpm for 12 h. After 12 h mixing, dope the solution by adding maleic acids and mix at speed 150 rpm for 12 h. The solution will turn from dark blue to dark green to indicate that acid doping is taken place. The solution is then left to stand for 4 h to remove air bubble. Next, cast the solution on a nonwoven polyester support fabric and immediately immersed in DI water at room temperature for 24 h. During the 24 h, DI water will be change once after 12 h (Loh et al., 2008). Polyelectrolyte coating Polyelectrolyte coating of PAni membrane will be done by dipping the membrane into an anionic and cationic solution. Anionic solution will be used in this research is PAA while PAH is for cationic solution. To prepare anionic solution, PAA will be dissolve in DI water and 5 M HCl will be used to adjust the pH to 3.5. For cationic solution, PAH also will be dissolve in DI water but to adjust the pH solution to 3.5, 5 M NaOH will be used. Next, PAni membrane will be immerse in PAA solution for 10 min followed by two DI water rinses for 2 and 1 min respectively. The PAni membrane then will be immerse in PAH solution for 10 min followed by two DI water rinses for 2 and 1 min respectively. These complete the first bilayer of polyelectrolyte coating. For the next layer, the steps before will be repeated again which is starting from immersing in anionic solution and then cationic solution. After finish the process, the membrane need to be wash with ammonia and let it to fully dry before bei ng proceed with characterization (Jinhua Dai et al., 2005 unknown, yr). Characterization of PAni membrane Flow chart Stock and reagent solutions preparation PAni synthesis by chemical polymerization Characterization of EB powder by using GPC Membrane production and casting Polyelectrolyte coating Characterization Analysis GANTT CHART MILESTONE Table 7.1 : Milestone EXPECTED OUTCOMES/COMMERCIALIZATIONS REFERENCES Chapman, P., Loh, X.X., Livingston, A.G., Li, K., Oliveira, T.A.C. (2007). Polyaniline Membranes for The Dehydration of Tetrahydrofuran by Pervaporation. Journal of Membrane Science, 309 (2008), pp. 102-111. Loh, X.X., Sairam, M., Bismarck, A., Steinke, J.H.G., Livingston, A.G., Li, K. (2008) Crosslinked Integrally Skinned Asymmetric Polyaniline Membranes for Use in Organic Solvents. Journal of Membrane Science, 326 (2009), pp. 635-642.

Germany experienced a period of political calm Essay

The Stresemann years of 1924-29 have often been portrayed as the â€Å"golden years† of Weimar Germany; however this idea has been challenged my many historians. During this period there was an element of political calm but it was mainly typified by political inaction and a failure of coalition governments to agree on any important issues. Economic development did occur but was minimal, and the period was one of slow economic growth and â€Å"relative stagnation†. Similarly, there were several signs of social progress and cultural development, but the years were significantly characterised by cultural polarisation. Therefore the blanket statement: â€Å"Germany experienced a period of political calm, economic development and social progress in the mid 1920s† ignores the problems in Weimar Germany at this time and is therefore not entirely correct, each clause contains some validity. In politics, there was a clear reduction in extra-parliamentary attempts opposing the government and political system. This was particularly significant as the preceding 1919-23 period was characterised by such threats from the Left and Right of the political spectrum, for example the Spartacist uprising, the Kapp Putsch and the Beer Hall Putsch. However, the mid 1920s cannot be said to have been years of political stability. Despite the reduction in threats to the Weimar state, the parliamentary system failed to mature and develop – a political stagnation developed, not a political calm. Seven governments were formed and dissolved during the 1924-29 years, and only two of these claimed a working majority. This clearly illustrates the failures of the coalition system to produce a strong working government with sufficient support (something which was greatly needed in order to tackle the problems that faced the new democracy.) Instead, a â€Å"stalemate† ensued. Blame fo r this can be partly placed upon the political parties of this time, as up until 1914 they had no experience of forming governments or compromising in order form governments. Instead, parties acted more as interest groups rather than as national parties of  government. This was significant as the electoral system of proportional representation relies on the cooperation of political parties. However the German People’s Party (DVP)’s increasing association with the interests of business caused it to refuse to form a coalition with the Social Democratic Party (SPD). Between 1924 and 1928 the SPD resisted becoming involved in the formation of any viable coalition government because they believed that a coalition with the â€Å"bourgeois† parties would lead to a compromise of party ideals. As a result the influence of the SPD in the Reichstag was significantly reduced and the parties rejection of political responsibility undermined the democratic system; contradicting the key concepts of representation and accountability. Other, smaller issues undermined the political system, as Chancellors fell out over very petty things such as the use of the imperial flag. Thus it can be concluded that throughout the years 1924 to 1929 politics was inefficient and suffered from stagnation. The simple claim that the years were a period of political calm is misleading as, despite illustrating a brief reduction in attempts at extra-parliamentary action, it ignores the many problems which underpinned politics at this time. Historians commonly argue that during the mid 1920s the German economy experienced currency stability, slow growth and â€Å"relative stagnation.† There was significant economic growth but it was underpinned by significant industrial unrest and unstable foreign investment. Therefore simple claims of economic development during this period do not show the whole picture. Having said this, there was a definite increase in monetary stability which can be attributed to the introduction of new currency in 1923, the Rentenmark, and also the consequences of the Dawes Plan which brought about a significant influx of foreign capital. The monetary stability brought about by the establishment of the Rentenmark was a great improvement after the hyperinflation of 1923 and helped the classes who had suffered most during this time. However, the foreign investment which enabled the reconstruction of German industry to take place was potentially dangerous as it could be quickly and easily withd rawn if there was a downturn in the world economy. Thus although it enabled a degree of economic progress, the measure could be seen as temporary and had the potential to bring disaster  upon the German economy if it fell through. Some of the growth in available capital was also due to the Dawes Plan though which decreased the rate of repayments, though. National Income in 1928 increased by 12% from 1913 levels and industry experienced massive growth. These positives are balanced by the sobering reminder that monetary stability was based on foreign capital, and the fact that other areas suffered change and unrest. Unemployment figures also question the image of the 1920s as the â€Å"golden years† of Weimar Germany. By 1928, 3 million Germans, accounting for 15% of the workforce, were unemployed. These figures suggest that many of the economic problems which would later surface were actually rooted in these supposed years of stability, and any economic progress related to the mid 1920s is only relative, in comparison to the dire state of the German economy in the periods directly before and after it. There was considerable social progress in the mid 1920s as advancements in welfare, housing and public health improved the standard of living for many German people. After the war there was an increased need for welfare and in 1924 the system for claiming relief and assessing the needs of the claimant was codified (although many claimants continued to receive benefits at a subsidence level.) Other changes in the law signalled social progress, such as the 1927 Labour Exchanges and Unemployment Insurance Law which introduced unemployment insurance. Thus the welfare state was significantly increased, though it remained imperfect. In general terms of public health, standards improved. Better health insurance and medical provision led to a reduction in deaths from certain diseases such as tuberculosis and pneumonia. The position of women mainly remained the same as the proportion of women working outside the home increased only minimally. Although there was a growing number of women in ne w areas of employment in the civil service, teaching and social work, attitudes towards women working were generally conservative. However, arguably more significant than these minimal signs of social progress was the cultural polarisation which existed in this period. During 1919-24 a new style unique to the Weimar Republic developed and manifested itself in the media. The new movement stressed objectivity and matter-of-factness. Alienation from the Weimar Republic was a common theme of writing, theatre and cinema highlighted social issues with a new  seriousness and architecture was dominated by the Bauhaus movement. This â€Å"Weimar culture† was used to show the injustices that existed in Weimar society. However the objectivity of this new movement was in direct contrast to the nostalgic romanticism and escapism of popular literature. Similarly, the modern Bauhaus movement stood against the majority of Germans traditional taste. Some historians have claimed these supposed cultural advancements were just the movement of a â€Å"counterculture† which many opposed. It is also important that the cultural developments which did take place did nothing to help stabilise the Weimar Republic; instead they only served to further divide Germany society, this time on cultural lines. Neither culture showed particular support for Weimar Germany and its values, thus this limited form of social progress did nothing to improve the stability of the Weimar Republic. In conclusion, the statement: â€Å"Germany experienced a period of political calm, economic development and social progress in the mid 1920s† is only partly true. Germany did experience limited political calm, a somewhat greater degree of economic development, and a small degree of social progress. However the claims made in this statement are broad and ignore the complexities of German politics, society and economics in the mid 1920s. Although there were suggestions of political calm, many problems were evident within German politics at this time such as political paralysis – the above statement ignores this. There was monetary stability and cases of economic development during these years, far greater than social or political stability and improvements. However the causes of this economic progress and stability can be considered superficial, as fundamental weaknesses in the German economy ensured it remained far from stable. Lastly, there were improvements in public health and welfare services but they were limited and imperfect. Social developments were evident but what may be considered social progress by some engendered hostility in others, resulting in cultural polarisation. In contrast to the rosy image painted in the original statement, this period saw the beginning of economic pressures and social discord which were to worsen after 1929. Many historians have traced the weaknesses which contributed to the breakdown of democracy in the early 1930s back to this period.

Ruthless Argue Essay Samples Strategies Exploited

Ruthless Argue Essay Samples Strategies Exploited Discursive writing can be rather a handful to write. The introduction usually starts out with some type of background details. Also, deciding on the most suitable topic is critical. The topic chosen for the purpose should be attractive in the view of many readers. What's more, it's easy to receive your money back if, for instance, you don't think out cooperation is successful. After conducting some research, you're come across the best topics that can help you to find something you'd love to talk about in your undertaking. After all, the task of the student is to just explain how other positions might not be well informed or updated on this issue. Most Noticeable Argue Essay Samples As an example, in college, you might be requested to compose a paper from the opposing perspective. When the topic was decided, it's crucial to come up with an argument surrounding the exact same. An argumentative essay example will reveal the should possess some very important components which make it better in the practice of convincing. Any excellent task finishes with an amazing conclusion and the very best examples of the argumentative essay will arrive in with a conclusion which has an overview of all of the points together with a gist of the evidence s provided. Actually, the action of arguing involves providing proof to back up your claim, with or without emotions. A conclusion is, without a doubt, the most essential portion of the argumentative essay as possible either support the excellent impression or destroy it entirely. It plays a vital role in the sense that it ties up the entire essay. An excellent conclusion will summarize all data that has happened in the post and use it in order to give one final reason why you need to join our side. Details of Argue Essay Samples Inspiration to make your own advertising or media argumentative essay topics isn't tricky to discover. Writing an incredible essay on technology does not need to be difficult. The exact same thing applies when the question is all about an argumentative essay. When it has to do with writing one, you would like to make sure that you select a topic you will be passionate about or objective about. An argumentative essay is among the absolute most troublesome papers you're able to create. It requires you to decide on a topic and take a position on it. It presents both sides of an issue. It is a type of essay that presents arguments about both sides of an issue. Care ought to be taken that the data utilized in the essay is related to the topic. You should offer information which is related to your thesis. The superb argumentative Scholarship Essay Samples formats and samples are just world-class, and they'll inspire folks to write argumentative essays in various competitions. Discursive writing is a kind of formal writing that discusses a particular topic. Nowadays it's very difficult to locate a trustworthy essay writing service. The most frequently encountered paper writing service that the bulk of our clients require is essay writing. Look for an expert essay writing service as you have. Your tutor isn't going to supply you with the ideal grade on the grounds of just what you've written, but much importance is supplied to the overall appearance. Thus, in order for each man to never feel the pressure of societal conformity, it's important that schools keep a feeling of diversity. Before embarking on the writing it is critical that students start by evaluating the evidence both for and against the problem.

The Atomic Bomb On The World War II - 1437 Words

On August 3, 1945, President Truman authorized the use of a weapon that would ultimately end almost 200 thousand lives. Three days later, a B-2 bomber dropped the atomic bomb on the Japanese city Hiroshima, ending World War 2 and beginning a new era of warfare. In the following decades, open warfare between nations possessing atomic technology became impossible and a political rift opened between nuclear and non-nuclear nations. In the late 1930s, global tensions crystallized into war and a quest for a new super-weapon quietly began around in the world in numerous, underfunded laboratories. As Europe crumbled under the might of the Axis powers, American scientists began to explore the possibilities of nuclear fission in warfare.†¦show more content†¦The subsequent explosion was described as â€Å"... an intense flash of light, a sudden wave of heat, both followed by a powerful shock wave.† A plume of radioactive fire preceded a massive mushroom cloud that extended over the valley after the test. The results confirmed that the most powerful weapon in the world had been created. A month later, two other atomic bombs were dropped on Hiroshima and Nagasaki with a shockwave felt for miles in the surrounding regions and a political shockwave felt around the world. Long before the atomic detonations above Hiroshima and Nagasaki, Stalin was aware of the American nuclear program. Following the detonation, it was not the technological significance of the bombs that shocked Stalin, who already had spies in the Manhattan Project, rather, it was the alacrity with which the Americans used the weaponry that proved surprising. In what Stalin later described as a â€Å"rare misjudgement†, the Soviet dictator admitted to underestimating the American ambition for victory. Fundamental idealistic differences between the Soviet Union and the United States, no longer overshadowed by the threat of Germany, immediately began to brew conflict following the surrender of imperial Japan. As America celebrated victory, the Soviet Union accelerated its ongoing nuclear program and prepared for another war. Back in the United States, the next big story was Soviet espionage in the