Synthesis of Molecularly Imprinted Polymers for Selective Extraction of Fungicides from River Water

Salma, Bakhtiar (2019) Synthesis of Molecularly Imprinted Polymers for Selective Extraction of Fungicides from River Water. PhD thesis, Universiti Malaysia Sarawak (UNIMAS).

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Abstract

Modern agricultural production depends heavily on the employment of agrochemicals, including artificial and natural fungicides. The utilization of these fungicides can bring about event of deposits of these chemicals, and their metabolites, in each segments of environment, in particular water and soil. Their presence in the environment is a worldwide known contamination problem. Depending on the chemical nature and level of contamination, these fungicides can have severe effects on both the terrestrial as well as aquatic life and eventually on humans. The latest variety of high selective binding efficiency adsorbents, molecularly imprinted polymers (MIPs), having excessive sample load capacity, high binding selectivity, low cost and simple preparation, are wide applied for preconcentration and high efficient separation of small analytes in different matrices. MIPs are synthetic polymers (artificial receptors) having extremely high recognition ability for template molecules. Fungicides of interest in this study were 2-phenylphenol, 2, 4, 6-trichlorophenol and thymol. Therefore, three set of imprinted polymers were prepared using 2-phenylphenol, 2, 4, 6-trichlorophenol and thymol as template molecules for selective extraction of these fungicides from river water samples. Three set of MIPs using 2-phenylphenol, 2, 4, 6-trichlorophenol or thymol as template molecules were synthesized using precipitation polymerization via non-covalent approach. Functional monomers used were styrene, methaacrylic acid, acrylamide, the crosslinker used were divinylbenzene, ethylene glycol methacrylic acid and N,N-bismethylene acrylamide for 2-phenylphenol, 2, 4, 6-trichlorophenol and thymol respectively and AIBN was used as initiator. The non-imprinted polymer (NIP) were synthesized in the same procedure but with the omission of template molecule. After the extraction of template molecules with suitable extraction solutions, a number of parameters that can affect selective binding efficiency of MIPs such as pH of the solution, initial concentration, MIP dosage, contact time, agitation rate, were optimized. The optimal parameters for 2-phenylphenol, 2, 4, 6-trichlorophenol and thymol with efficiencies were: pH 7 (99.45%, 85%, 92%) , optimal initial concentration 25 ppm (99%), 30 (92.26%), 20 (96%) , MIP dosage 100 mg (99.45%), 200 mg (87%), 300 mg (94%), contact time 90 min (99 %, 85%, 94%), and agitation speed was 250 rpm (99%, 87%, 92%) respectively. All the MIPs and NIPs were characterized by FTIR and EDX for their chemical and elemental analysis. The morphological characterization of all the MIPs and NIPs were recorded by using SEM and for surface area, pores size and pores volume determination BET was used. All the imprinted polymers were applied on real samples that is river water samples all the MIPs showed good binding efficiencies in these samples for 2-phenylphenol the efficiencies were 88%, 2, 4, 6- trichlorophenol 94%, thymol 98 % in river water respectively. All the MIPs showed better efficiencies as compared to their structural analogues.

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