Chemical synthesis of ZnO, CuO, MnO and FeO Nano adsorbent and their application in anionic reactive blue turquoise 71 dye (RB-71 dye) and real effluents remediation: Batch adsorption and column studies

Industrial dye production chemicals contribute significantly to environmental pollution. This study explores the use of nanotechnology, specifically nano fertilizers and adsorption technology, for efficient removal of synthetic anionic dyes and enhancing agricultural production. Nano adsorbents (MnO, FeO, ZnO, and CuO) were generated using the co-precipitation method. Optimal conditions for Manganese oxide (MnO) were pH 2 (33.2 mg/g), dosage 0.01 g/50 mL, and adsorption capacity 77.2 mg/g. FeO optimal conditions were pH 2 (21.5 mg/g), dosage 0.01 g/50 mL, and qe 40.5 mg/g. CuO optimal conditions were pH 2 (28.2 mg/g), dosage 0.01 g/50 mL, and qe 71.3 mg/g. ZnO optimal conditions were pH 2 (25.4 mg/g), dosage 0.01 g/50 mL, and qe 64.2 mg/g. Pseudo 1st order and Freundlich sorption isotherms were best-fit models. Endothermic reactions were observed, indicating the sorption process's nature and feasibility. Electrolyte concentrations affected the sorption potential. Surfactants/detergents reduced sorption efficiency. 0.5 N NaOH proved most effective for desorption. In column studies, optimal conditions for acidic RB-71 dye sorption were 3 cm bed height, 1.8 mL/min flow rate, and 70 mg/L inlet dye concentration. Metal oxide showed exhibited crystal and polymorphs structure. FT-IR spectra depicted metal-oxide peaks between 400 and 899 cm−1. SEM micrograph reveals a spherical shape with an approximate size of 10–50 μm. The adsorption method's novelty lies in its easy handling, eco-friendliness, and cost-effectiveness, making it a promising technology for practical-scale application in addressing dye pollution.