Sintesis Kopolimer Gel Berbasis NIPAM (N-isopropylacrylamide), Kitosan dan Asam Akrilat Sebagai Adsorben Limbah Elektroplating

Abstract

Indonesia is one of the worst countries in Asia in terms of wastewater treatment which results in environmental pollution. One of the factors is the electroplating industry that produces heavy metal waste. One of the heavy metal wastes from electroplating is chromium metal that become a threat to humans and the environment because it can cause acute poisoning, accumulated in the human body and damage the ecosystem. One of the methods used to regenerate heavy metal waste is by employing zwitterionic betaine gel. However, this method has its disadvantages with the presence of intra-intrachain associations that inhibit the ionic group's ability to adsorb ions by the charge group interaction.

This study aimed to improve the gel adsorption ability by reducing the association of intra-intrachain copolymers through separately synthesis the anionic gel (NIPAM-co-acrylic acid) and cationic gel (NIPAM-co-chitosan). NIPAM-co-chitosan and NIPAM-co-acrylic acid gels were synthesized through polymerization reactions using N,N,N',N'-tetramethylethylenediamine (TEMED) as accelerators and N,N'-methylenebisacrylamide (MBAA) as a crosslinker. Innitially TEMED, MBAA, NIPAM and chitosan or acrylic acid were mixed in distillated water with a total volume of 100 ml. The solution was stirred for 10 minutes, purged with N2 gas with a flowrate of 500 ml/min in four neck flask at 10 ^oC. Ammonium peroxodisulfate (APS) was then added into solution. The polymerization reaction occurred for 6 hours. In this study the adsorption/desorption of metal ions by pH-thermosensitive gel are investigated in various pH, and weight balance between NIPAM-co-anionic and NIPAM-co-cationic gel. The effects of the temperature and the conditions employed in the preparation of the gel, i.e., monomer concentration on the extent of adsorption of metal ions on the gel were also elucidated. The adsorption and desorption behavior of the gel is discussed by considering the swelling degree of the gel as well as the transition temperature of poly(NIPAM-co-chitosan) and poly(NIPAM-co-acrylic acid).

Based on the results of FTIR analysis, the vinyl groups peak of the copolymer gel decreased compared with that of its constituent monomers. It can be concluded that the synthesis of copolymers was successful. While based on the swelling degree test using an electroploting waste solution, the higher the temperature of the solution, the lower the swelling degree of the gel. Moreover, gel porous occurred because of the higher synthesis temperature.