PRECONCENTRATION AND SELECTIVE TRACE ANALYSIS OF Pb(II) IONS USING ION IMPRINTED POLYMERS (IIPs)

• Main Author: Ela Kartika, Siska
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/32564
• Institution: Institut Teknologi Bandung

Rapid industrial development provide a positive impact by increasing economic sector but also can have a negative impact in the form of industrial waste causing environmental pollution. Hazardous industrial waste caused by heavy metal ions is a major concern. Lead is a heavy metal ion which becomes the primary indicator of pollution by the United States Environmental Protection Agency (US EPA). Direct determination of lead in environmental samples is often difficult due to its trace level concentrations and a complex matrix interference. Therefore, preconcentration and separation techniques which can simplify the matrix is usually necessary prior to determination. Various analytical techniques for the preconcentration of trace metal ions have been developed using ion imprinted polymers (IIPs). IIPs selectivity due to the memory effect of the polymer with metal ion and specific ligand interaction. Pb-imprinted polymers (Pb-IPs) was successfully synthesized through the polymerization of anthranilic acid as the monomer and formaldehyde as the cross-linking agent in the presence of binary complexes of Pb(II)-4-(2-pyridylazo) resolcinol and HCl I M as a catalyst. Polymerization takes place through a condensation reaction. Synthesis of Pb-IPs was carried out with the reflux for 10 hours at a temperature of 140 ± 10 oC. Formed polymer is a polymer in which there are ions of Pb(II). In order to perform its function as a functional material that has selective cavities for Pb(II) ions, the Pb(II) ions in the polymer matrix was removed with EDTA 0,05 M to obtain Pb-IPs. For comparison also the polymer synthesized without template or non-imprinted polymers (NIPs). Characterization of NIPs dan Pb-IPs have been carried out using FTIR and SEM-EDS. NIPs and Pb-IPs was successfully prepared indicated by the presence of CH2 bridge vibration in FTIR spectra of polymers. Shift of absorption bands of C=O and C-N on unleached Pb-IPs and leached Pb-IPs indicated an interaction between C=O and C-N group with Pb(II) ions forming –Pb-O- and –Pb-N-. SEM-EDS results showed that unleached Pb-IPs has a rougher surface morphology and contained clusters with higher brightness levels. Clusters on the surface indicating the presence of Pb(II) ions in the polymer matrix. These results were confirmed by EDS indicating % mass Pb(II) ions in the polymers matrix by 5.89 %. While leached Pb-IPs has a smoother surface morphology and did not show a significant difference in brightness levels. This indicates that Pb(II) ions which was originally contained in the polymer matrix can be removed by the addition of EDTA. These results were confirmed by EDS information. Retention properties characterization by batch method showed that the retention capacity of Pb-IPs was 18.68 mg/g at pH 5 with a contact time of 10 minutes. The retention process of Pb(II) ions by Pb-IPs obey both types of adsorption isotherm, adsorption isotherm of Langmuir and Freundlich. Relative selectivity coefficients of Pb(II)/Cu(II), Pb(II)/Cd(II), and Pb(II)/Zn(II) are 1.60; 2.44; and 2.47 respectively. Good selectivity for Pb(II) ions can be obtained even in complex matrices. Pb-imprinted polymers have been used for the preconcentration and determination of Pb(II) ions in river water samples. Concentration of Pb(II) ions in river water samples was 0.06 mg/L with the percent recovery of 99.73 %. The percent recovery value showed that the synthesized functional materials are well enough to use for the trace analysis of Pb(II) ions. In addition, Pb-IPs can also be used as fungsional materials for mini-column in the flow injection analysis (FIA) system. On-line preconcentration using Pb-IPs can be applied for Pb(II) ions preconcentration with the dynamic preconcentration factor up to 15 times and minimum mass detected of 3.21 ?g. Pb-IPs functional materials can be used to repeatedly for retention-elution process through the FIA system with precision 3.00 % (n = 3).