Study of continuous lead removal from aqueous solutions by marble wastes: efficiencies and mechanisms

• Published in: International journal of environmental science and technology (Tehran) 2015-09, Vol.12 (9), p.2965-2978
• Main Authors: Mlayah, A., Jellali, S.
• Format: Article
• Language: English
• Subjects: Aquatic Pollution; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Science and Engineering; Original Paper; Soil Science & Conservation; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 1735-1472; 1735-2630
• DOI: 10.1007/s13762-014-0715-8

Lead removal from synthetic solutions and real wastewater by Bianco Gioia marble wastes as abundant, renewable and eco-friendly materials was studied under different experimental conditions in a continuous stirring tank reactor. These marble wastes were found to be very efficient in removing lead for several experimental situations. Indeed, for initial aqueous pH values higher than 3.6, a lead removal efficiency of about 100 % was achieved even for high aqueous concentrations (200 mg L −1 ), important feeding flow rates (60 mL min −1 ) and low marble waste dosage (2 g L −1 ). The best removal capacity (175.7 mg g −1 ) was obtained for an initial lead concentration of 200 mg L −1 , a marble waste dose of 5 g L −1 and an aqueous pH of 5. Even using the real wastewater with low aqueous pH (1.1), lead was also completely removed using 20 g L −1 of the tested marble wastes. According to the energy-dispersive spectroscopy and X-ray diffraction analyses, lead removal seems to be controlled by both precipitation as cerussite (PbCO 3 ) and hydrocerussite (Pb 3 (CO 3 ) 2 (OH) 2 ), and adsorption onto the surface particles through cation exchange and complexation. The proposed low-cost material efficiently removes lead present in synthetic solutions and real wastewaters and constitutes an interesting environmental management option.