Decolorization of Malachite green dye from wastewater by Populus deltoides: three-level Box–Behnken design optimization, equilibrium, and kinetic studies

摘要: Decolorization of Malachite green in aqueous solution by adsorption onto Populus deltoides sawdust (PSD) was optimized through a four-factor, three-level Box–Behnken design response surface methodology. The influences four independent variables such as initial pH (3–7), dye concentration (50–300 mg/L), adsorbent dose (0.2–2 g/L), and temperature (23–50 °C) were studied to optimize the condition removal. A natural log transformation suggested Box–Cox plot order enhance model significance. Regression analysis showed good fit experimental data second-order polynomial with high coefficient determination values ( R 2 = 0.996; adj.2 0.9913; pred.2 0.9769), F -value 213.03, p <0.0001 α 0.05). Under optimum all variables, viz., 6.02, 262.6 mg/L, 0.23 g/L 30.3 °C, maximum uptake q e) noted be 920.9 mg/g. equilibrium fitted well Langmuir isotherm 0.9949). Kinetic studies revealed that followed pseudo-second order. It found PSD is suitable for reuse times successive adsorption-desorption cycles loss 25.2% capacity.