ION IMPRINTED POLYMERS AS SELECTIVE MATERIAL FOR RETENTION, SEPARATION, AND PRECONCENTRATION OF MERCURY BASED FLOW INJECTION ANALYSIS

• Main Author: Nur Basir, Djabal
• Format: Dissertations
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/42069
• Institution: Institut Teknologi Bandung

Mercury is a heavy metal which is highly toxic to living organisms, so there special attention to the handling of waste mercury in the environment. The process of bioaccumulation or progressive increase in the concentration of mercury in natural aquatic ecosystems, and further accumulate through the food chain, will give harmful effects to humans are exposed to through food such as fish and shellfish. Likewise, using mercury in industrial products such as whitening cream cosmetics will be very dangerous. Therefore, it is necessary to monitor the mercury content in the environment, and against hazardous products that use mercury as a component of its manufacture. Fulfillment of methods that can use for retention, separation, and preconcentration in analyzing mercury concentrations in the complexity of samples in environments or industrial products with high selectivity and sensitivity, a new alternative method is needed. One of the innovations developed today is the use of ion imprinted polymers (IIPs) as functional materials for selective sorbent in the process of retention, separation, and preconcentration of metal ions. In this study, a polymer with mercury ions synthesized with a strategy of trapping by 3-mercaptopropyltrimethoxysilane (MPTS) ligands against Hg (II) ions in the polymer matrix. The SH group on the ligand will interact covalently with the Hg(II) ions and the other end of the ligand will be bound to the silica nucleus through the hydrolysis process, then polymerized with vinyltrimethoxysilane (VTMS) monomers and ethylene glycol dimethacrylate (EGDMA) as crosslinking agent. After the Hg(II) ions released from the polymer matrix, a selective printed will form for Hg(II) ions. The Hg-IIPs polymers formed can use as a selective sorbent in the process of retention, separation, and preconcentration of mercury- based flow injection analysis. Functional characterization has been carried out including physical characterization using FTIR, SEM-EDS, TGA, and BET analysis, then the characterization of retention conditions and separation is carried out by the batch method and preconcentration with Hg-IIPs-SPE column based on flow injection analysis (FIA). The results of the study with the batch method adsorption obtained optimum adsorption conditions was pH 4, contact time 90 minutes, maximum adsorption capacity (qm) was 62.27 mg.g-1 for Hg-IIPs and 28.91 mg.g-1 for NIIPs, second order pseudo adsorption kinetics, and Bi-Langmuir adsorption isotherm model. In this method, the effect of sorbent mass use studied, where the more sorbent mass, the higher the adsorption percent will be obtained, but the use of a lot of sorbent mass will tend to decrease the adsorption capacity (qe) value so that the material does not function effectively. The separation factor and selectivity of adsorption on Hg(II) ions with the presence of Pb(II), Cd(II), and Cu(II) ions obtained the higher separation factor (?) in quaternary solutions with the order of the degree of separation or selectivity is Hg/Cu > Hg/Cd > Hg/Pb. The adsorption-desorption cycle using the Hg-IIPs-SPE column in Hg(II) 40 mg.L-1 was carried out in 5 cycles for the preconcentration in 1 time and 2 times, wherein the percentage of the recovery obtained in the two preconcentration levels ± 95%. The reusability of Hg-IIPs sorbent shows that the adsorption process is still effective until the 4th cycle, which gives more than 50% adsorption. However, the reusability for the concentration of Hg (II) 0.5 mg. L-1 from the adsorption-desorption cycle obtained the percentage of adsorption, percentage of desorption, and percentage of recovery until the 5th cycle still reached 100%. The results of preconcentration with based of FIA-CVAAS using the Hg-IIPs-SPE column with 20 mg of sorbent, a flow rate of 1 mL.min-1, and carrier of pH 4 obtained dynamic retention capacity (qe) was 9.85 mg.g-1 in use analyte of 10 mg.L-1 Hg(II). The results of FIA-CVAAS analytical performance with 0.5 mL of 2.5 M HNO3 as eluent and 1 mL of analyte obtained the precision value was 2.06%; linearity was 0.9982; detection limit was 0.33 µg.L-1; the quantitation limit was 0.58 µg.L-1, and accuracy with percent of recovery was ±97%. In evaluating FIA performance, obtained an enrichment factor was 1.25 times, concentration efficiency was 17 samples per hour, and the consumptive index was 5 mL. The application of the use of FIA-CVAAS with the Hg-IIPs column on the determination of mercury content in whitening cream cosmetic products founded on products with the code: N99K and DR where indicated to contain mercury and exceeded the threshold required by regulations BPOM RI No.17 of 2014. The results of this study are expected to provide scientific contributions and information regarding the synthesis techniques and performance of Hg-IIPs sorbent. In the end, the Hg-IIPs material obtained through the synthesis process in this study can use as a selective sorbent for retention, separation, and preconcentration of mercury in the analysis based on FIA-CVAAS.