Adsorption of toxic metals from landfill leachate using orange and banana peel powders as adsorbents

Agricultural wastes are sustainable adsorbents to clean up toxic metals contaminated in water and wastewater. Understanding water chemistry is critical in innovating and finding processes that limit the removal of toxic metals. The study used orange and banana peels as adsorbents to simultaneously remove nickel, cadmium, and chromium from landfill leachate. The toxic metal concentrations in landfill leachate were 9.60 mg/L, 4.90 mg/L and 0.06 mg/L for Ni, Cd, and Cr, and 100 mL of landfill leachate and a dosage of 0.50 g, 1.00 g, 1.50 g, 2.00 g, and 2.50 g of orange and banana peel adsorbents. The adsorption efficiency of the orange peel adsorbent ranged from 99.90% to 99.99% for nickel, 97.00% to 99.98% for cadmium, and 59.30% to 98.18% for chromium and banana peel ranged from 99.55% to 99.99% for nickel, 99.16% to 99.96% for cadmium, and 45.67% to 82.91% for chromium in the landfill leachate. Qmax (mg/g) which is the maximum adsorption capacity ranged from −0.03 mg/g to 0.01 mg/g for orange peel and −13.16 mg/g to 0.01 mg/g for banana peel. The KF of the orange peel adsorbent for Ni, and Cd were larger values showing a stronger interaction. Ni had a higher affinity than Cd and Cr in the binding sites of the orange and banana peels. The orange and banana peel adsorbents are eco-friendly, simple, more cost-effective, and innovative methods for the removal of metals in leachate and wastewater. An adsorptive experiment of a similar design should be carried out at varied temperatures and contact times.