关键词: 铬(Ⅵ), 木质素磺酸钠, 吸附机理, 动力学, 热力学

Abstract: To address the issue of heavy metal Cr（Ⅵ） pollution, lignin-based activated carbon (SLAC) was synthesized from sodium lignosulfonate via Fe modification for the purpose of removing Cr（Ⅵ） from aqueous solutions. The influences of the Fe addition ratio, calcination time, and calcination temperature on the Cr（Ⅵ） adsorption capacity of SLAC during its preparation were examined, and the preferred SLAC adsorbent was subjected to structural characterization. Furthermore, the effects of solution pH, initial Cr（Ⅵ） concentration, adsorption time, and adsorption temperature on the adsorption process were investigated, along with the adsorption kinetics, thermodynamic behavior, and recycling performance of the adsorbent for Cr（Ⅵ）. The results demonstrated that the optimized SLAC adsorbent achieved a 98.6% Cr（Ⅵ） removal efficiency at pH=1 and an initial concentration of 20 mg/L. Adsorption kinetics followed pseudo-second-order models, and equilibrium data conformed to the Langmuir isotherm, with excellent recyclability observed over six cycles. The superior adsorption performance stems from enhanced Cr（Ⅵ） interaction via electrostatic attraction, oxygen-functional group complexation, and redox reactions, offering a promising solution for Cr（Ⅵ） removal from wastewater. This study provides novel insights into practical Cr（Ⅵ） treatment applications.

Key words: chromium(Ⅵ), sodium lignosulfonate, reaction mechanism, kinetics, thermodynamics