Performances of Cu‐Zn hydroxyacetate double salts adsorbent for the removal of different kinds of anionic dyes: Modeling of adsorption isotherms and adsorption kinetics

Abstract A layered Cu‐Zn hydroxyacetate double salt (CuZnAc) was synthesized from ZnO and Cu(CH 3 COO) 2 and tested for adsorption of anionic dyes (Evans Blue, Yellow Thiazole, Indigo Carmine, Brilliant Blue R) with varying charges. X‐ray diffraction, Fourier‐transform infrared spectroscopy, and thermogravimetric analysis confirmed the layered structure. Adsorption was pH‐independent (5–9.5) and highly dependent on dye structure, with capacities of 727.40 (EB), 746.00 (YT), 204.47 (IC), and 105.95 (BBR) mg g −1 . Isotherm data fitted best to Sips/Toth (EB), Sips (IC), and Redlich‐Peterson (YT, BBR) models, while kinetics followed pseudo‐first order (EB, YT, BBR) and pseudo‐second order (IC). Thermodynamics revealed spontaneous, endothermic adsorption with increased interfacial randomness. The material retained 58%–65% efficiency after five regeneration cycles. CuZnAc shows promise for removing diverse anionic dyes from wastewater.