Application of response surface methodology for modeling and optimization of malachite green adsorption by modified sphagnum peat moss as a low cost biosorbent

Abstract

ABSTRACT This study focused on the adsorption of malachite green (MG) using hydrochloric acid modified sphagnum peat moss (SPM) from aqueous solution. A response surface method (RSM) based on the Box–Behnken design (BBD) was used to determine the effects of initial dye concentration (20– 60 mg L –1 ), adsorbent dosage (0.6–1.6 g L –1 ) and pH of the solution (2.5–6.5). Characterization of the SPM has been accomplished by SEM, BET, and FTIR analysis. Based on the obtained equilibrium time (90 min), in each initial MG concentration, adsorption kinetics was better described by the pseudo-second order kinetic model and the results showed that the adsorption isotherm data were fitted well to the Langmuir isotherm. Calculate values of the statistical parameters such as R 2 , R 2 adj , and R 2 pred , were 0.9946, 0.9850 and 0.9144, respectively. Applying the method of the desirability function, optimization of SPM dosage (0.6 g L –1 ), initial MG concentration (60 mg L –1 ) and pH (6.43) gave a maximum adsoption uptake of 93.71 mg g –1 with desirability of 1.000 by the modified SPM. Regeneration ratio of SPM was also investigated for the removal of MG.