Decolorization of Synthetic and Real Leather Dyeing Wastewater Using Purolite Anion-Exchange Resin: Experimental, Theoretical and Reusability Investigation

Tannery wastewater poses a substantial environmental threat due to its high content of toxic and persistent dyes. This study evaluates the potential of Purolite A400E Anion-exchange resin for removing Melioderm Black AFP 135 (MB-AFP135) dye from synthetic And real tannery effluents. Adsorption experiments explored the effects of contact time, pH, resin dosage, temperature, dye concentration, And the presence of inorganic salt. The optimal adsorption capacity of 35 mg g⁻¹ was achieved within 60 min for an initial MB-AFP135 concentration of 0.2 g L⁻¹ with a resin dose of 5 g L⁻¹, which increased to 39 mg g⁻¹ using ground resin. The adsorption data fit the Langmuir isotherm model (R² = 0.990), revealing a maximum monolayer capacity of 2616.794 mg g⁻¹. Kinetic analysis indicated a strong correlation with the pseudo-second-order model (R² = 1). Thermodynamic parameters confirmed the process was spontaneous (ΔG° =—646.154 J mol⁻¹) and endothermic (ΔH° = 1835.03 J mol⁻¹). Furthermore, regeneration tests showed that the resin-maintained efficiency over four cycles. Experiments conducted on real tannery wastewater demonstrated a dye removal efficiency of approximately 94% under optimal conditions. These results underscore Purolite A400E’s effectiveness as a sustainable and scalable solution for dye removal from tannery effluents.