New generation of magnetic microporus material for enhancing route for methylene blue removal from waste water

Abstract

A statistical analysis was carried out for adsorption of methylene blue onto nickel oxide impregnated magnetic biochar to determine the optimised condition of methylene blue dye adsorption to attain greater equilibrium adsorption capacity. The mangosteen peel derived magnetic biochar underwent pyrolysis process at zero oxygen environments at 800 0C for 25 min duration. The Design of Experiment (DOE) of the batch adsorption of methylene blue dye onto magnetic biochar was investigated by interacting agitation speed, contact time and adsorbate pH. Design Expert software version 7.0 with Central Composite Design (CCD) method was employed to obtain a minimum number of experiments with maximised operating parameters interactions. The adsorbent dosage and adsorbate initial concentration were fixed at 0.3 g and 50 mg/L respectively, throughout the experimental study. The optimised condition to attain highest removal percentage of 97% was recorded at pH above 7.0, agitation speed of 125 rpm and 30 min contact time. The adsorption isotherm was evaluated using various adsorption isotherm models namely Langmuir, Freundlich, Tempkin and Dubinin–Radushkevich isotherm models. Moreover, the effect temperature on adsorption process was investigated through thermodynamics studies at various temperatures. The magnetic biochar produced at optimum condition possesses total BET surface area of 819.7 m2/g and pore volume of 0.137 cm3/g.