Synthesis and characterization of kaolinite coated with copper oxide and its effect on the removal of aqueous Lead(II) ions

Abstract

Abstract The removal of Lead (Pb2+) ions from waste water in the aquatic environment by copper oxide–kaolinite composite forms an important step involved in the reduction of Lead ions in the environment. The study investigated the synthesis, characterization, and application of copper oxide–kaolinite composite in the removal of Lead ions from aqueous systems. The synthesis of the composite involved a trimetric process to produce the copper oxide (CuO)–kaolinite composite. The characterization involved the determination of cation exchange capacity, specific surface area, and spectral analysis by sodium saturation method, nitrogen gas adsorption techniques, and scanning electron spectroscopy, respectively. The determination of parameters affecting the reaction mechanism and reaction kinetics involved the use of batch mode techniques. The findings indicated a reaction mechanism that was less than one proton coefficient, higher mass transfer rates when compared with uncoated kaolinite. Here, the intraparticle diffusion was higher than the value for the uncoated kaolinite. The reactions based on Pb2+ initial concentration indicated that the coated kaolinite gradually became saturated as the concentration was increased. The reactions based on solid concentration (Cp) demonstrated a complex change in the capacity of adsorption over different Pb2+ concentrations (10–40 mgL−1) and solid concentrations (2–10 gL−1). Here, the reduction in specific surface area, particle size increase, mineral aggregation, and concentration gradient effect controlled the complex changes in adsorption. In conclusion, the copper oxide–kaolinite composite significantly enhanced the adsorption of Pb2+ ions.

Keywords

• Activation
• Synthesis
• Characterization
• Kaolinite
• Pb ions
• Reaction mechanism