Optimization of adsorption of methyl orange from aqueous solution by magnetic CoFe₂O₄/ZnAl-layered double hydroxide composite using response surface methodology

Abstract The CoFe 2 O 4 /ZnAl-layered double hydroxide (LDH) composite was successfully developed through a facile co-precipitation method, characterized, and applied as an effective adsorbent for the removal of methyl orange (MO) dye from aqueous solutions. central design (CCD) response surface methodology (RSM) employed to estimate optimize process variables such initial MO concentrations, solution pH, dosage, contact time. 98.878% adsorption efficiency obtained at concentration 18.747 mg l −1 MO, with dosage 0.048 g, pH 2.770, time 85.890 min. Analysis variance (ANOVA) confirmed significance predicted model (R = 0.9844). Kinetic equilibrium studies indicated that experimental data were best described by pseudo-second-order kinetic Langmuir models. maximum monolayer capacity /ZnAl-LDH 42.3 g .