Synthesizing nanoparticles of zinc and copper ferrites and examining their potential to remove various organic dyes through comparative studies of kinetics, isotherms, and thermodynamics

Abstract

Nanoparticles of zinc ferrite (ZnFe2O4) and copper ferrite (CuFe2O4) were synthesized, and characterized, and these materials were applied for removal of organic dyes of alizarin yellow R (AYR), thiazole yellow G (TYG), Congo red (CR), and methyl orange (MO) from industrial wastewater through adsorption technique. Synthesis of ZnFe2O4 and CuFe2O4 was achieved through chemical co-precipitation method. These nanomaterials were characterized for physicochemical properties using XRD, FTIR, BET, VSM, DLS, Zeta-potential, and FESEM-EDX analytical instruments. BET surface areas of ZnFe2O4 and CuFe2O4 were 85.88 m2/g and 41.81 m2/g, respectively. Adsorption-influencing parameters including effect of solution pH, adsorbent quantity, initial concentration of dye pollutant, and contact time were examined. Acidic medium of the solution favored higher percentage of removal of dyes in wastewater. Out of different isotherms, Langmuir equilibrium isotherm showed the best fit with experimental data, indicating monolayer adsorption in the treatment process. The maximum monolayer adsorption capacities were found as 54.58, 37.01, 29.81, and 26.83mg/g with ZnFe2O4, and 46.38, 30.06, 21.94, and 20.83mg/g with CuFe2O4 for AYR, TYG, CR, and MO dyes, respectively. From kinetics analysis of the results, it was inferred that pseudo-second-order kinetics were fitting well with better values of coefficient of determination (R2). The removal of four organic dyes from wastewater through adsorption technique using nanoparticles of ZnFe2O4 and CuFe2O4 was observed to be spontaneous and exothermic. From this experimental investigation, it has been inferred that magnetically separable ZnFe2O4 and CuFe2O4 could be a viable option in removal of organic dyes from industrial wastewater.