Exploring the Potential of Aerated Concrete and Clay Bricks from Construction and Demolition Waste as Adsorbents for Pb(II) Removal from Aqueous Solutions

This study aimed to evaluate the potential of utilizing aerated concrete (AC) and clay bricks (CB) sourced from construction and demotion waste (CDW) as low-cost adsorbents for the removal of Pb2+ from aqueous solutions. The effects of various parameters, including particle size, solution pH, contact time, adsorbent dosage, and initial Pb2+ concentration, were analyzed through batch experiments. The results indicated that AC performed more efficiently in removing lead ions than CB under all the tested conditions. The highest removal efficiency of Pb2+ with AC was 99.0%, which was achieved at a pH of 5.0, contact time of 1 h, an adsorbent dosage of 5 g/L, and an initial Pb2+ concentration of 100 mg/L. The maximum adsorption capacities of AC and CB were 201.6 mg/g and 56.3 mg/g, respectively. The adsorption isotherm data of the adsorbents were successfully modeled using both the Langmuir and Freundlich models. The removal of lead ions from aqueous solutions by both adsorbents is primarily achieved through adsorption and microprecipitation. Compared to CB, AC exhibited superior performance, attributed to its larger specific surface area, pore volume, and alkalinity. The cost-effectiveness and availability of AC make it a promising candidate for treating of Pb-contaminated wastewater, providing a new way for resource utilization of CDW