Preparation of Sulfur-doped Porous Carbon and Its Electro-adsorption Performance for Heavy Metals in Desulfurization Wastewater

Heavy metal pollution in desulfurization wastewater from coal-fired power plants has huge potential harm to the environment. Among them, the problem of heavy metal ions such as Pb2+, Cd2+ and Cr3+ is particularly prominent. Efficient and targeted removal of relevant heavy metal ions is a huge challenge for wastewater purification. For this reason, sulfur-doped porous carbon materials were prepared by template method to selectively remove heavy metal ions from wastewater with electro-adsorption. The results show that the removal efficiency of Pb2+, Cd2+ and Cr3+ in wastewater can still reach 99% after 5 cycles. The electric adsorption experiment was carried out for the actual desulfurization wastewater from a coal-fired power plant in northern China, the mass concentrations of Pb2+, Cd2+ and Cr3+ could be effectively reduced to less than 0.2 µg/L. Through structural, morphological and electrochemical characteri-zation, it is found that S/PC3 has excellent ion transport channels (mesoporous ratio is 91.06%) and electrochemical performance (117.3 F/g, 1 A/g). At the same time, the appropriate sulfur doping amount improves the site activity of sulfur-doped carbon materials, and makes the sulfur atoms (Lewis soft base) with heavy metal ions (Lewis soft acid) combine.