胺硫改性生物炭对水溶液中不同重金属离子的吸附特性及吸附稳定性

以玉米秸秆为原料热裂解制备生物炭,利用二乙烯三胺和二硫化碳,通过酸化氧化,曼妮希反应胺基改性、二硫化碳巯基取代对生物炭进行胺硫双基团改性,研究胺硫改性生物炭(BC-SN)对Pb2+、Ni2+及Cd2+在单一和三元体系下的吸附特性和吸附稳定性.表征分析证实了生物炭表面胺硫双基团改性成功,且具有比表面积大、表面官能团丰富的...

Heavy Metal Ion Adsorption Properties and Stability of Amine-sulfur Modified Biochar in Aqueous Solution

A novel biochar was prepared by modification with corn straw, ethylene triamine, and carbon disulfide, and its adsorption properties and stability with respect to heavy metal ions in single and mixed systems (Pb²⁺, Ni²⁺, and Cd²⁺) were investigated. Characterization analysis confirmed the successful modification of an amine-sulfur double group on the surface of the biochar, which had abundant functional groups with a large specific surface area. Adsorption experiments under the single system indicated that the adsorption equilibrium time was 4 h and the optimum dosages were 1, 0.8, and 1.2 g·L^-1. The adsorption met the conditions of the quasi-second-order kinetic equation. Under the ternary system, the adsorption equilibrium time was reduced to 1.5 h, the optimum dosages were 0.4, 1.6, and 0.8 g·L^-1, and the adsorption sequence was Pb²⁺ > Cd²⁺ > Ni²⁺. The total amount of adsorption was 0.67 mmol·g^-1, which was higher than that of single heavy metal ions, indicating that amine-sulfur modified straw biochar (BC-SN) has an improved treatment effect on polluted water under the coexistence of three heavy metal ions. The Pb²⁺ and Cd²⁺ adsorbed by the biochar was stably bound in the form of heavy metal sulfide and a chelated amino group. In contrast, the adsorption of Ni²⁺ was via the mixed adsorption of various functional groups. When Pb²⁺ and Cd²⁺ compete for adsorption, the binding energy is higher and adsorption stability is more reliable.