硫酸钙晶须的制备及其对亚甲基蓝的吸附性能研究

以磷石膏为原料,添加一定量的助晶剂,采用水热合成法制备了硫酸钙晶须,利用电子显微镜、SEM、XRD及FTIR对硫酸钙晶须的表面形貌、物相特征等进行了表征.制备出的晶须形貌较好,为直径1.56 μm、长径比24的纤维状结构.考察了硫酸钙晶须对亚甲基蓝的吸附性能,探讨了吸附时间、晶须投加量、pH值对亚甲基蓝吸附的影响.利用Langmuir吸附等温方程、Freundlich吸附等温方程和Temkin吸附等温方程对吸附行为进行了描述,结果表明硫酸钙晶须易于吸附亚甲基蓝,吸附过程主要是单分子层吸附.用颗粒内扩散方程和准二级吸附动力学方程对实验数据进行回归分析,结果表明后者能够反映硫酸钙晶须对亚甲基蓝的吸附机理.

Study on Preparation of Calcium Sulfate Whiskers and Its Adsorption Performance on Methylene Blue

Taking phosphogypsum as raw material and adding a certain amount of crystallization promoting agent, calcium sulfate whiskers were successfully prepared by hydrothermal synthesis method. Morphology, structure of calcium sulfate whiskers were characterized by electron microscope, SEM, XRD and FTIR. The whiskers prepared had good morphology with fibrous structure of diameter 1.56μm and length-diameter ratio 24. The adsorption performance of calcium sulfate whiskers on methylene blue was studied and the effects of adsorption time＇addition amount of calcium sulfate whiskers and pH value on the adsorption of methylene blue were explored. The Langmuir isotherm, Freundlich isotherm and Temkin isotherm equations were applied to describe the adsorption behavior, and the results showed calcium sulfate whiskers could easily adsorb methylene blue and the adsorption process was mainly monolayer adsorption. The particle internal diffusion equation and quasi-two adsorption kinetic equation were used in the regression analysis of experimental data, and the result showed quasi-two adsorption kinetic equ.ation could represent the adsorption mechanism of methylene blue on calcium sulfate whiskers.