Pengaruh Properti Kopolimer Zwitterionic Sulfobetaine terhadap Kemampuan Adsorpsi-Desorpsi Gel pada Ion Logam Berat

Abstract

In 2016, it was stated that 92.1% of the quality of river water in Indonesia was polluted by a heavy metal ion. Such heavily polluted water is not feasible to use, let alone consumed. In this study, NIPAM-co-DMAAPS gel which consists of monomer N-isopropylacrylamide (NIPAM) and N,N’-dimethyl(acrylamidopropyl) ammonium propane sulfonate (DMAAPS) was synthesized to be applied as an adsorbent to overcome the environmental pollution. DMAAPS is thermosensitive and zwitterionic. This zwitterionic has two charges, positive and negative, in the same repeating unit, which can be used to adsorb cations and anions simultaneously. While NIPAM is thermosensitive, it is used as a spacer to avoid inter-chain, intra-chain, and intra-group bonding between charged groups on DMAAPS zwitterion homopolymers. It is also used as an adsorption agent because the ability to change from hydrophilic to hydrophobic with temperature change. In this research, poly(NIPAM-co-DMAAPS) properties such as functional groups, hydrophobic or hydrophilic properties, viscosity, transition temperature and correlation with its gel adsorption ability were evaluated in various concentrations of NIPAM:DMAAPS of 95:5, 90:10, and 85:15 in Cr(NO₃)₃ solutions as the source of Cr³⁺ ion which are dominantly found in electroplating waste. Poly(NIPAM-co-DMAAPS) was synthesized through free radical polymerization reactions with N,N,N’,N’-tetramethylenediamine (TEMED) as an accelerator, ammonium peroxodisulfate (APS) as the initiator. Whereas for gel synthesis, cross-linker of N,N’-methyl-enebisacrylamide (MBAA) was added. The polymerization reaction lasts for 6 hours at 10 ^oC by keep flowing the nitrogen gas during the reaction. The IR spectra showed that the polymerization process was carried out successfully, and the highest adsorption of heavy metal ions occurred in the copolymer gel with the ratio NIPAM:DMAAPS of 85:15.