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Home > Synthesis and Characterization of Polymer Beads and Hydrogel Metal Nanoparticle Composites for Adsorption and Catalytic Applications

Synthesis and Characterization of Polymer Beads and Hydrogel Metal Nanoparticle Composites for Adsorption and Catalytic Applications

Thesis Info

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External Link

Author

Muhammad Ajmal

Program

PhD

Institute

Quaid-I-Azam University

City

Islamabad

Province

Islamabad.

Country

Pakistan

Thesis Completing Year

2016

Thesis Completion Status

Completed

Subject

Chemistry

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/2956/1/Muhammad_Ajmal_Chemistry_2016_QAU_06.06.2016.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727461448

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This work concerns with the synthesis, characterization and applications of hydrogels and polymer beads. Hydrogels of micron dimension and of different chemical compositions were prepared. Poly(methacrylic acid) (p(MAc)), poly(methacrylic acid-co- acrylonitrile) (p(MAc-co-AN)), poly(sulfobetain methacrylate) (p(SBMA)) microgels were prepared. Modification of nitrile groups to amidoxime groups was accomplished by treating with hydroxylamine hydrochloride. The prepared hydrogels were used as microreactors for the synthesis of monometallic Cu, Co, and Ni nanoparticles as well as bimetallic Co-Fe nanoparticles. The catalytic applications of the hydrogel metal nanoparticles composites were investigated for the reduction of nitro compounds such as 4-nitrophenol (4-NP), 2-nitrophenol (2-NP) and 4-nitroaniline (4-NA). Catalytic activities of the prepared composites were also studied for the reduction of cation and anionic dyes such as eosine Y (EY), methyl orange (MO), and methylene blue (MB). Simultaneous reductions of two or three compounds like 4-NP, EY and MB were also carried out in the presence of the prepared catalysts. The bare (p(MAc-co-AN) microgels and their magnetic composites were also used as adsorbents for the removal of heavy metal ions such as Cd (II) and Cr (III), industrial dyes like MB and rhodamine 6 G (R6G) and a widely used herbicide paraquat (PQ) from aqueous medium. Tremendous increase in the adsorption capacity was observed after the conversion of nitrile to amidoximes. The magnetic microgels were found to retain their magnetic characteristics even after adsorption of pollutants. The poly(acrylonitrile) (p(AN)) beads were prepared and the nitrile groups were converted to amidoximes. The adsorption ability of the p(AN) beads was investigated by using them as adsorbents for the removal of Cd (II), MB, R6G and PQ from aqueous medium. Another type of modifiable poly (vinylbenzyl chloride) (p(VBC)) beads were prepared and the reactive vinyl chloride groups were treated with 3, 3ʹ-iminodipropionitrile (IDPN) to introduce two nitrile groups on each reactive site. The nitrile groups were then converted to amidoxime groups. These amidoximated beads were then applied as adsorbents for the removal of anionic dyes such as MO and EY as well as for the removal of toxic dichromate and arsenate from aqueous medium. Three adsorption isotherms; Langmuir, Freundlich, and Temkin adsorption isotherms were applied on the adsorption data to find the nature of adsorption. The pseudo first order and iipseudo second order kinetics was also applied to investigate the kinetics of the adsorption experiments. The catalytic and adsorption results of this work are much better as compared to the previously reported work. To sum up, the microgels that can be employed for the synthesis of inherently magnetic, highly stable and reusable nano catalysts have been prepared. The most important outcome from this work is that the prepared microgel composite catalysts can be used for individual and simultaneous degradation of nitrophenols and cationic/anionic dyes pairs or in the triple combinations that may exist in the contaminated aquatic environments. In addition, polymer beads which can be easily modified and complete adsorption task within 45 minutes and can be easily removed from the adsorption medium are reported.
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جمہوریت سے ہی پاکستان کا مستقبل ہے

جمہوریت سے ہی پاکستان کا مستقبل ہے
ہر کس و ناکس کی پیہم جد و جہد اس کے مستقبل کے نکھار کے لیے ہوتی ہے۔ گذشتہ راصلوۃ آئندہ را احتیاط کے پیشِ نظر ماضی کو کر ید نا اہلِ لب کا شیوہ نہیں ہوتا صرف واقعات سابقہ سے حصول عبرت منشاء و مراد ہوتی ہے۔ حال کوبحسن و خوبی گزارنے کے ساتھ ساتھ مستقبل کی درخشندگی و تابندگی کے لیے کوشاں رہتے ہیں۔ جو پھر گیسوئے گیتیء استقبال میں مشاطگی کا فن سیکھ لیتا ہے۔ نابغۂ روزگارگردانا جاتا ہے۔
کوئی اپنا مستقبل سنوارتا ہے، کسی کی آواز یہ انگڑائیاں لیتی ہے کہ افراد خانہ کا مستقبل روشن ہو جائے ،کسی کی تمنایہ ہوتی ہے کہ میری قوم کا مستقبل مستنیر و منور ہو جائے ،کسی کے دل و دماغ کے کونے کھدرے میں یہ بات مہیمز ثابت ہونا شروع ہوتی ہے کہ روشن مستقبل ہی حاصل حیات ہے اور وہ اسی میں اپنی حیاتِ مستعار کے عظیم لمحات صرف کردیتا ہے۔
کتنا خوش نصیب ہے وہ شخص جو انفرادی کے بجائے اجتماعی سوچ کا حامل ہوتا ہے۔ اور پورے ملک کے لیے اس کی آرزو یہ ہوتی ہے کہ وہ درخشندہ و تابندہ مستقبل کی فضاء میں سانس لے۔ پاکستان کے مستقبل کی یہ خواہش صرف اور صرف جمہوری طرزعمل سے ہی پوری ہوسکتی ہے۔ پاکستان میں بسنے والے ہرشخص کی عزت و احترام صرف اور صرف جمہوریت سے ہی وابستہ ہے۔
جمہوریت میں ہر شخص کو گفتگو کی، تحریر کی، تقریر کی آزادی ہوتی ہے، وہ قانون کے دائرے میں رہ کر اپنی آواز ایوانوں تک پہنچا سکتا ہے، اور اُس کی حق وصداقت پر مبنی آواز سے ایوان بالا کے در و دیوار لرزنے لگتے ہیں ، ایوانوں میں موجود عوامی نمائندگان کی سوچ فلاح انسانیت کے کاموں کی تکمیل کے لیے مستعدومتحرّک ہو...

IMMEDIATE EFFECTS OF POST-ISOMETRIC RELAXATION AND STATIC STRETCHING ON QUADRICEPS MUSCLE DURING VERTICAL JUMP IN VOLLEY BALL AND BASKETBALL PLAYERS

Background and Aim: In today sports such as volleyball and basketball, Vertical Jump is considered as important component that enhance the performance of athlete. The aim of this study was to determine the effect of muscle energy technique on vertical jump performance in volleyball and basketball players. Methodology: This Randomized Clinical Trial was conducted at Islamic International University Islamabad. Twenty-nine athletes of age 18 – 35 playing basketball and volley as part time/domestic level were included. Post isometric relaxation technique was applied on group A (n=15) and static stretching was applied on group B (n=14). Surface electromyography activity of quadriceps and abdominal muscle was recorded, Stable time, airtime and vertical jump height were measured using two-axis force platform and vertical jump height was measured by motion sensor. Measurements were taken at baseline and immediately after applying interventions to both groups. Data entry and analysis were done by using software SPSS version 22. Results:   Of the 29 athletes, 15 were in the group A and 14 were in the group B. Immediate assessment of vertical jump height was not significantly improved by post-isometric relaxation relative to static stretching (p=0.594). Muscle recruitment, ground reaction and vertical jump height improved apparently after post isometric relaxation but not significantly. Conclusion: It appears that post isometric relaxation and static stretching of quadriceps shows no significant difference in vertical jump height.

Tunneling or Propping: Evidence from Family Business Groups of Pakistan

Corporate governance has two types of agency issues with respect to ownership and control of firms. The Type I agency issue is related to conflict of interest between shareholders and firm’s managers (i.e., principal-agent conflict); whereas, the Type II agency issue (i.e., principal-principal conflict) is between controlling (majority) shareholders and minority shareholders. The tunneling and propping in business group firms are examples of Type II agency issue. Tunneling is the process of expropriation or transfer of business resources by controlling shareholders from low cash-flow rights (CFR) firms to high CFR firms in a business group. Tunneling is carried out through certain transactions at the cost of minority shareholders in group firms. Whereas, propping is the opposite process through which resources are provided by controlling shareholders to firms under financial distress in a business group. This thesis examines these Type II agency issues between controlling and minority shareholders of firms related to family business groups of Pakistan. A family business group is a combination of two, or more firms under the control of a particular family. In this regard, the study examines whether tunneling, or propping is carried out in family business group firms, how it occurs and what impact it has on minority shareholders of these firms? The thesis has three major parts: first, this study explores regulatory and corporate environments in Pakistan; develops the pyramid ownership structures of family business groups; and examines the cash flow leverage, cash-flow rights and voting (control) rights of ultimate owners in family business group firms. The study finds that corporations in Pakistan have high degree of ownership concentration. Controlling shareholders own about 87% of firms with equal to or greater than 10% shareholding and 60% of firms with equal to or greater than 20% shareholding. Moreover, most of the businesses in Pakistan are controlled by families. In 62% of business group firms, families own about 20% or more top shareholdings. The study also finds considerable difference in voting, and cash-flow rights in family business group firms, which provides incentives for expropriation of resources. Secondly, the thesis focuses on finding the empirical evidence of tunneling, or propping in family business groups firms of Pakistan by taking a sample of 326 non-financial firms listed on Pakistan Stock Exchange (PSX) for the period 2004-17. The study finds that majority or controlling shareholders expropriate minority shareholders by tunneling or transferring resources from group affiliated firms containing low CFR of majority owners. While measuring the sensitivities of firms to the industry earnings shocks through indirect methodology; the empirical results elucidate that about 31% resources are tunneled from low to high CFR group firms. The study further finds that equity held by directors (representing majority shareholders) has negative relationship with earnings of minority shareholders of low CFR group firms. Thirdly, the thesis examines different categories of four thousand five hundred Related Party Transactions (RPTs) taken place among sample firms during the period 2008-2013. Using the direct methodology, the study categorizes, classifies, describes and analyses the RPTs. The study finds that group affiliated firms extensively involve in RPTs as compared to non-group, foreign and state-owned firms. The controlling shareholders significantly use various RPTs for both, tunneling and propping depending upon the characteristics of firms, and corporate governance. Moreover, the study finds that considerable amount of intra-group loans is outstanding on firms’ financial statements. Besides, direct cash payments, cash receipts, assets sales and trade of goods & services have been observed as major RPTs, and sources of Type II agency issues. The study further finds that market assigns lower multiple of reported earnings for the top other receivable balance firms and vice versa. The study finally finds that firms are less likely to reduce their outstanding other receivables balances despite qualified audit opinions and lower returns. Overall, the results show that business interests of dispersed minority shareholders are xi significantly affected by crafty operations of majority shareholders in family business group firms mainly because of pyramid ownership structure and inadequate enforcement mechanism of corporate governance.These findings have certain implications for regulatory institutions, firm management, shareholders, and researchers.