虾壳粉对水溶液中阴、阳离子型染料的吸附

采用废弃虾壳制备吸附剂处理含刚果红或亚甲基蓝的溶液。考察了温度、吸附时间、初始浓度、吸附剂投加量和初始溶液pH对吸附效果的影响并构建了去除率预测模型，并对吸附等温线、吸附动力学和吸附热力学进行系统研究。结果表明：虾壳粉对刚果红和亚甲基蓝的吸附分别在24 h和4 h时达到平衡，平衡吸附量随吸附时间、初始浓度及吸附剂投加量的增加而增大；刚果红平衡吸附量随pH升高而增大，亚甲基蓝平衡吸附量几乎不随pH变化。在15 ℃下，吸附剂投加量为1 g·L-1，刚果红吸附的最优条件为接触时间24 h、pH=4，在该条件下，虾壳粉对刚果红的饱和吸附量为276.64 mg·g-1；亚甲基蓝吸附的最优条件为接触时间4 h、pH=12，在该条件下，虾壳粉对刚果红的饱和吸附量为1.44 mg·g-1；虾壳粉对2种染料的吸附过程以物理吸附为主，符合准二级动力学方程。虾壳粉对阴离子型染料的吸附效果较优，对阳离子型染料有一定吸附性能，是一种经济高效的染料废水吸附材料。

Adsorption of cationic and anionic dyes from aqueous solutions by shrimp shell powder

Shrimp shell-based bio-adsorbent was prepared and used to treat the simulated wastewater with congo red or methylene blue. The effects of temperature, adsorption time, initial dye concentration, adsorbent dosage and initial solution pH on adsorption efficiency were investigated, the prediction model for removal efficiency was subsequently built, and the adsorption isotherm, adsorption kinetics and adsorption thermodynamics were systematically studied. The results showed that the adsorption of congo red and methylene blue by shrimp shell powder reached equilibrium at 24 h and 4 h, respectively. The equilibrium adsorption capacity increased with increasing adsorption time, the initial dye concentration and adsorbent dosage. As pH increased, the equilibrium adsorption capacity of congo red increased, while the equilibrium adsorption capacity of methylene blue almost presented no change with pH. At 15 ℃, absorbent dose of 1 g·L-1, the optimum contact time of 24 h and pH=4, the saturated adsorption capacity of congo red by shrimp shell powder was 276.64 mg·g-1, while that of methylene blue was 1.44 mg·g-1 at pH=12. The adsorption of congo red and methylene blue onto shrimp shell was mainly considered as a physical adsorption process and could be described by a quasi-second-order model. Overall, shrimp shell-based bio-adsorbent exhibited an excellent removal efficiency for cation dye, while a slight removal one for anion dye. It is expected to be an economical and efficient material for wastewater treatment.