Sorptive removal of malachite green from aqueous solution by magnetite/coir pith supported sodium alginate beads: Kinetics, isotherms, thermodynamics and parametric optimization

Abstract

The present study deals with facile synthesis of magnetite/coir pith supported sodium alginate beads from naturally available waste materials which was further employed for removal of malachite green dye from synthetic aqueous solution underaparametric optimized condition of the adsorption process. Several operating parameters such as stirring speed (50-250 rpm), adsorbent weight (0.5-7 g/L), pH (2-9), temperature (35- 55 degrees C), and initial malachite green dye concentration (50-250 mg/L) were used to study the adsorption in a batch operation. The central composite design approach of response surface methodology in design-expert software revealed maximum removal efficiency of malachite green at pH of 7; initial malachite green dye concentration of 150 mg/L; adsorbent weight of 3g and temperature of 35 degrees C which showed adsorption efficiency (>98%). Analysis of Variance (ANOVA) suggested the equation to be significant for the process with a greater impact of adsorbent weight and malachite green concentration rather than the other three contributing parameters. Extensive kinetic, isotherm, thermodynamic, and eco-toxicological studies were performed to understand the behavior and sustainability of the developed materials. Final observation assured the reusability of the processed beads and hence showed gigantic potential for implementation on industrial-scale evaluation for the treatment of wastewater.