Removal of copper (II) ion using chitosan-graft-poly(methyl methacrylate) as adsorbent

Abstract

Synthesis of the poly(methyl methacrylate) (PMMA) from methyl methacrylate monomer has been successfully carried out by reversible addition-fragmentation chain transfer polymerization (RAFT) techniques using 4,4’-Azobis(4-cyanopentanoic acid) (ACPA) initiator and 4-Cyanopentanoic acid dithiobenzoate (CPADB) as RAFT agent with mole ratio of MMA: CPADB: ACPA fixed at 148: 3: 1. The obtained PMMA macro RAFT was used as initiator together with N,N-dicyclohexylcarbodiimie (DCC) and 4-dimethylaminepyridine (DMAP) as coupling agent and catalyst respectively in synthesis of CS-g-PMMA. The effect of reaction hours on grafting percentage was investigated by manipulating the reaction time to 2, 8, 14 and 22 hours. The CS-g-PMMA obtained at 22 hours showed the highest grafting percentage and efficiency which 72% and 36% respectively. All the homopolymers and grafted copolymers were then used to fabricate electrospun using electrospinning techniques. However, only PMMA electrospun was successfully obtained whereas chitosan and CS-g-PMMA were unsuccessful in electrospinning due to the instrument setup and solubility restriction. The grafted copolymers and PMMA electrospun was characterized by using ATR-FTIR and SEM. The adsorption efficiency of powdered-form CS-g-PMMA and homopolymers was investigated and analysed using F-AAS. It has been proven that longer hour grafted copolymers have high adsorption efficiency as compare to shorter hour grafted copolymers. The highest adsorption efficiency obtained was 86.18% shown by 22 hours CS-g-PMMA. Thus, it expected CS-g-PMMA electrospun will provides maximum adsorption as compared to powdered-form copolymers due to its high surface area, high permeability and porosity of the membrane.