Removal of lead ions (Pb 2+ ) from water with lignite-activated carbon modified by water vapor and Aluminum chlorohydrate

The presence of lead compounds in the environment has become a significant concern, prompting increased interest in the use of activated carbon for removing lead from wastewater. Activated carbon uses physical and chemical methods to adsorb lead. In order to enhance the adsorption of lead, water vapor method and adding Aluminum chlorohydrate method were used to enhance the adsorption capacity of activated carbon. Various factors such as carbonization temperature, activation temperature, water vapor and polyaluminum chloride ratio were investigated to assess their impact. Optimal conditions for preparing polyaluminum chloride dispersed lignite activated carbon were determined to be 500°C for carbonization temperature, 700°C for activation temperature, a coal/water mass ratio of 10 g·g−1, and a mass ratio of 0.12 g·g−1. Under these conditions, the adsorption efficiency reached 80.23%. Compared with non-activated carbon, the adsorption capacity was increased by 26%. The characterized polyaluminum chloride dispersed lignite-activated carbon revealed a thermally stable porous surface with a BET surface area of 334.83 m2·g−1 and a crystalline surface attributed to α-Al2O3 formation during activation. The addition of Aluminum chlorohydrate led to a change in the surface zeta potential from positive to negative, enhancing lead adsorption on activated carbon. Experimental data were fitted well with the pseudo-second-order kinetic model. This method provides a theoretical basis for adsorption of lead on coal-based activated carbon.