Removal of Lead from Aqueous Solutions by Polyethylene Waste/Nano-manganese Dioxide Composite

An adsorbent composite based on waste polyethylene and manganese dioxide was synthesized, characterized and its capacity to remove Pb2+ from solutions was investigated. Chemical activation of PE bags was achieved by the reaction with potassium permanganate. This was to increase their susceptibility toward photo-degradation and thermal degradation by the introduction of functional groups, such as hydroxyl and carboxyl groups, as evident from the new IR bands appeared at 3400, 1710, and 1630 cm(-1). Further, the composite was fabricated by thermal or chemical dissociation of potassium permanganate, and its structure was confirmed by FTIR, XRD and SEM. Nano-structure manganese dioxide in the amorphous phase was identified. The adsorption results confirmed that the prepared adsorbent can effectively remove Pb2+ ions from aqueous solutions, with a maximum adsorption capacity of 50.5 mg g(-1). Both intra-particle diffusion and film diffusion contribute to the rate-determining step in the adsorption process. The composite can be regenerated using HCl solution (0.5 mol L-1) with Pb2+ recovery percentage reached 95 %. After serving as a promising absorbent for Pb2+, manganese oxide can be removed by hydrolysis with acid (6.0 M HCl) and the polymer with enhanced susceptibility toward degradation can be disposed off.