纳米高效活性白土对亚甲基蓝的吸附性能研究

Study on Adsorption Performance of Nanometer High-Efficiency Activated Clay towards Methylene Blue

为提高辽西膨润土原矿的吸附性能,采用“硫酸-盐酸-乙酸(5∶5∶2)混酸法”制备纳米高效活性白土,设计了3种膨润土对亚甲基蓝的吸附实验,采用紫外分光光度计检测试样的吸光度值,采用XRD、FTIR及SEM对3种膨润土进行表征分析,并进行了吸附热力学与动力学研究。结果表明:该纳米高效活性白土的活性度为210.9 mmol/100 g,游离酸0.13%,其最佳吸附条件为333 K,pH=7;其对亚甲基蓝的去除率最高可达78.1%;其层间距较原矿有明显增大,活性位点明显增多;推断3种膨润土对亚甲基蓝的吸附反应均为自发的放热反应,同时具有高相关系数的伪二级动力学模型更适合描述活性白土吸附亚甲基蓝的动力学过程。该纳米高效活性白土对化工企业废水的处理有一定的指导意义。

In order to improve the adsorption performance of bentonite raw ore in Liaoning, the "sulfuric acid-hydrochloric acid-acetic acid(5∶5∶2) mixed acid method" was used to prepare nanometer high-efficiency activated clay. Then, the adsorption experiment of three kinds of bentonite towards methylene blue was designed and the absorbance value of the samples was measured by ultraviolet spectrophotometer. Besides, the three kinds of bentonites were characterized by XRD, FTIR and SEM and the adsorption thermodynamics and kinetics were further studied. Results showed that the activity of the nanometer high-efficiency activated clay was 210.9 mmol/100 g, the free acid was 0.13%;the optimal adsorption condition was 333 K and pH=7;the maximum removal rate on methylene blue could reach 78.1%. The interlayer spacing was obviously larger than that of the raw ore, and the number of active sites increased significantly. It was inferred that the adsorption reactions of the three bentonites to methylene blue were all spontaneous exothermic reactions, and the pseudo-second-order kinetic model with high correlation coefficient was more suitable for describing the kinetics of the adsorption of methylene blue by activated clay. The nanometer high-efficiency activated clay had certain guiding significance for the treatment of wastewater in chemical enterprises.