Removal of malachite green by polyacrylamide-g-chitosan gamma-Fe2O3 nanocomposite-an application of central composite design

The material PACT@gamma-Fe2O3 was synthesized via oxidative free radical polymerization of acrylamide monomer in presence of gamma-Fe2O3 nanoparticles as a filler by grafting with chitosan biopolymer. The utility of the material was explored towards the removal of malachite green (MG) dye from the wastewater. Various kind of process variables were optimized by well-known statistical tool termed as response surface methodology (RSM) and central composite design (CCD). The optimized variables obtained by CCD were found to be contact time 170.28 min, pH 6, adsorbent dose 0.75 g, MG concentration of 60 mg L-1. Under these optimized conditions, the predicted removal percentage of MG dye by PACT@gamma-Fe2O3 was calculated 77% which agrees well with the experimental value of 73% with desirability of 1.0. Based on the mathematical model application, it was observed that the experimental data verily inclines in direction of the Langmuir model with variable temperature conditions (298-318 K). The dynamics of the reaction defines that the mechanism of uptake of MG molecules by using PACT@gamma-Fe2O3 take place through the formation of a coordination bonds between the solute and the material within the liquid perimeter.