Single/Competitive Adsorption Removal Of Pb2+/Cu2+/Ni2+ By Oxygenated Activated Carbon From Synthetic And Industrial Wastewaters

Abstract

Industrial wastewaters contain heavy metals that should be safely removed before disposal. Adsorption removal by activated charcoal is commonly used because of its cost-effectiveness and high adsorption capacity. Competition between metals requires raising the charcoal adsorption capacity.

The objective of the current study is to use wood from Salix trees to produce Activated Charcoal and then use H₂O₂ reactivation treatment to raise its adsorption capacity by developing Oxygenated Activated Charcoal (O-AC). O-AC is then used to remove Pb²⁺, Cu²⁺ & Ni²⁺ from synthetically polluted solutions, and in steady-state fixed-bed two-column system for removing these metals and other salts from industrial wastewater to concentrations below the Maximum Permissible Limits (MPLs).

Oxygenation treatment increased the EC of O-AC by +110%, surface charge by +177.7%, specific surface area by +73.9% and pore size by +31.4%. Best adsorption capacity was obtained at contact time of 40 minutes, O-AC dose of 0.1 g/500 ml, and solution pH 5 – 7. For initial concentrations around 40 mg/l for each of the studied metals, the net overall average adsorption capacity for the studied metals in single-, bi- & tri-metal solutions was 173.71 mg/g, which is almost four times higher than published studies. Fixed-bed system removed Lead, Copper, and Nickel & TDS concentrations from 22.0, 28.0, 18.62 & 1350.0 mg/l, down to 0.01, 1.0, 0.1 & 138.54 mg/l; respectively, which are below the MPLs. It is recommended to use the developed O-AC fixed-bed two-column system for competitive removal of the studied metals from industrial wastewaters with similar conditions.