DETERMINATION OF CARBARYL IN GROUND WATER BY USING MAGNETIT AS A CORE-SHELL OF MOLECULARLY IMPRINTED POLYMER

• Main Author: Mulyadi, Dikdik
• Format: Dissertations
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/56846
• Institution: Institut Teknologi Bandung

Carbaryl insecticide, one of the carbamate pesticides, has been extensively used for pest control due to their low persistence and high effectiveness. Because its widespread and intensive use, residues of carbaryl have the potential to contaminate the environment. In addition, this residue is toxic, so that it can endanger human healthiness, and a serious problem in the food and processing industry for agricultural products and cause problems of food safety in many places. Many efforts have been made to solve the above issues, by using molecularly imprinted polymer which selective for separatin and analysis of carbaryl in water. But some drawbacks to MIPs have restricted their widespread application, such as slow mass transfer, irregular shape, incomplete template removal, poor site accessibility, or heterogeneous distribution of binding sites. One of the promising alternatives to overcome thisweakness is imparting magnetism to the MIPs and then using magnetic separation. Magnetic separation technology, in which polymers are prepared using fabricating the MIPs on the surface of a magnetic substrate, has received remarkable attention in recent years for its potential application in separation and extraction. Recently, magnetic molecularly imprinted polymers (MMIPs) have attracted significant attention attributing to the fact that they not only exhibit specific selective binding for the template molecule but also have outstanding magnetism The synthesis of magnetic imprinted polymers by pre-grafting the amino functional magnetit, 3-aminopropyltriethoxysilane (APTES), on the surface of the silica coated magnetic substrate. APTES was used for amino functionalization of the silica coated Fe3O4 nanoparticles. Amino groups were used for immobilization of the template molecules on the magnetic surface and additionally to react with - C=C- of cross-linker, ethylene glycol dimethacrylate (EGDMA), by the Michael addition reaction. The sorbent was synthesized in the presence of carbaryl and EGDMA as the template and cross-linker, respectively. Removing template from the polymer used eluent methanol : acetic acid = 9:1(v/v). Several adsorption parameters that affect MMIPs adsorption on carbaryl were carried out, including pH, contact time, mass of sorben, adsorption capacity of MMIPs on the initial concentration of carbaryl, selectivity to analog compounds, the effect of solvent on adsorption-desorption and reusibility on MMIPs. The effect of temperature on the adsorption capacity of MMIPs on carbaryl was also studied. Calculation of adsorption kinetics and adsorption isotherms of MMIPs. The result of this study using batch method adsorption obtained that the optimum adsorption conditions were pH 4, time of adsorption was 60 minutes. The maximum adsorption capacity (qmax) for MMIPs and MNIPs were 57,04 mg/g and 44,11 mg/g, respectively. The adsorption kinetics of MMIPs and MNIPs follow a pseudo second-order kinetics model, respectively. Meanwhile, MMIPs and MNIPs adsorption isotherms follow Langmuir adsorption isotherms. Based on the results of this study the effect of mass on adsorption capacity, the mass of MMIPs sorbent used was 10 mg. Based on the calculation results, the selectivity of MMIPs is more selective for carbaryl compared to carbofuran and malathion. The results of the optimization of the adsorption and desorption solvent obtained were metanol:acetic acid = 9:1(v/v) which resulted the highest adsorption/desorption percent. The MMIPs replication test against carbaryl can be used again for three replications. The results of the adsorption thermodynamics of MMIPs showed that the adsorption capacity of MMIPs decreased with increasing temperature. The values of ?Ho and ?So are -4,869 kJ/mol and -50.88 kJ/mol, respectively, while the values of ?Go at temperatures of 298, 313, and 333 K are 10,23; 10,75; and 11,45 kJ/mol, respectively. The results of the analysis of carbaryl in ground water samples showed that the percent adsorpstion of MMIPs was 100% of carbaryl with a % recovery and precision (% RSD), 90,71 and 1,1, respectively. The limits of detection (LOD) and quantification (LOQ) of this method were 1,67 mg/L and 6,24 mg/L, resvectively. The results showed that magnetite cored molecular imprinted polymers could be used to separate and analyze carbaryl and showed good selectivity, precision and recovery.