Adsorption of Pb and Cd from Aqueous Solutions by Porous Carbon Foam Derived from Biomass Phenolic Resin.

Due to its lightweight and superior adsorption properties, carbon foam is frequently employed for the removal of heavy metal pollutants from aqueous solutions. In this study, a novel modified carbon foam (M-CF) was successfully synthesized for the effective removal of Pb and Cd from water. The synthesis involved partially substituting phenol with the liquefaction product of bamboo powder, followed by modification with a silane coupling agent (KH560) and foaming with n-hexane-loaded activated carbon (H/AC). The prepared carbon foam was comprehensively characterized, and its adsorption performance and mechanism for Pb and Cd in aqueous solution were investigated. The results showed that M-CF possessed a uniform and well-developed spherical pore structure and demonstrated excellent removal capacity for Cd and Pb. The adsorption process conformed to the Sips isotherm model and the pseudo-second-order kinetic equation, with maximum adsorption capacities of 22.15 mg·g and 61.59 mg·g for Cd and Pb, respectively. Mechanistic analysis revealed that the removal of Cd and Pb was a result of the synergistic effect of physisorption and chemisorption, accompanied by complexation. Furthermore, precipitates formed during the adsorption process were found to be mainly composed of hydroxides, carbonates, and PbS. This research demonstrates the efficacy of carbon foam prepared from bamboo powder waste as a partial phenol substitute for the efficient removal of Pb and Cd from water, thus expanding the preparation pathways for novel heavy metal adsorption materials.