Abstract
MgAlNi-BaFe ternary layered hydroxide (UMLDH) and its calcined (CMLDH) form were synthesized and tested as adsorbents for methyl orange dye (MO) uptake from water. The adsorptive performances of the new magnetic nanocomposites were modeled, evaluated and optimized via response surface methodology (RSM). The UMLDH and CMLDH maximum removal efficiency and adsorption capacities data were fitted into RSM models with insignificant lack of fit (p-values<0.05) and high R-2 = 0.991-0.997. The UMLDH and CMLDH MO adsorption capacities increased with decrease in both pH and initial MO concentration and decreased when the temperature was increased. Under optimal operating conditions, pseudo-second-order described kinetics of MO sorption on the nanocomposites, while the Freundlich isotherm gave the best fits for both the two adsorbents. The MO uptake simultaneously incorporated both mono and multi-layer surface adsorption involving strong electrostatic attraction and chemical interactions between MO and the adsorbents surface functional groups. Respectively, the obtained maximum Langmuir theoretical sorption capacity of 715.44 and 708 mg/g, indicated profoundly improved MO sorption capacities compared with many other magnetic-LDHs. These results demonstrate the potential of MgAlNi-BaFe as excellent adsorbents for effective remediation of dyes wastewater effluents.