Removal and recovery of lead from wastewater using an integrated system of adsorption and crystallization

Abstract This study explores the feasibility of an integrated system comprising adsorption and crystallization in a pellet reactor to remove and recover lead from aquatic environment. The selective adsorption of Pb 2+ over Ca 2+ and Mg 2+ was investigated using citric acid modified sugarcane bagasse (SCA) in batch and column systems. Selective separation of Pb 2+ from the mixed solution was achieved at a molar ratio 3.22 C o , b a t c h C a + M g / C o , b a t c h P b 2+ . In addition, synthetic lead wastewater with characteristics simulating the concentrate from desorption of saturated SCA was further treated in a fluidized bed denoted as pellet reactor. Lead (II) was quantitatively recovered at optimized conditions of pH 10, molar ratio [CO 3 2− ]: [Pb 2+ ] = 3:1, superficial velocity 9.55 m/h, and initial lead concentration 2.43 mM. The well-controlled crystallization process of cerussite on the surface of grain sand in the pellet reactor is comparable with the chemical equilibrium speciation data obtained by Visual MINTEQ. Overall, the developed system comprising adsorption combined with a pellet reactor was found sufficient to remove and recover lead as PbCO 3 from wastewater.