颗粒羟基氧化锆的除氟性能

以羟基氧化锆粉末为原料,制备颗粒羟基氧化锆,评价了颗粒羟基氧化锆对溶液中F-的吸附性能。结果表明:颗粒羟基氧化锆除氟过程符合Freundlich吸附等温线模型和拟二级动力学模型,F-的吸附过程包括液膜扩散和颗粒内的孔扩散;pH在3～4时,颗粒羟基氧化锆的氟吸附量达到最大值27.72 mg/g,其他范围内pH的升高或降低都会导致氟吸附量的降低;Cl-对颗粒羟基氧化锆除氟过程无明显影响,而SO24-和PO34-对颗粒羟基氧化锆除氟过程影响较大,且浓度越高影响越大;扫描电镜和X射线能谱测试结果显示颗粒内随着颗粒深度的增加,F-含量逐渐降低,F-在颗粒内部的传质过程受到阻碍,SO24-和PO34-对颗粒羟基氧化锆除氟的干扰作用主要发生在颗粒表面。

Fluoride adsorption by granular hydroxyl zirconia

The adsorbents of granular hydroxyl zirconia(GHZ) were prepared from the hydroxyl zirconia powder,and their properties of defluoridation were studied.The results showed that the F-adsorption of GHZ fitted better with Freundlich isotherm model than Langmuir model,and the kinetic data showed that it fitted pseudo-second order model.The process of F-adsorption involved liquid membrane diffusion and intra-particle diffusion.The adsorption capacity of GHZ can reach the maximum value of 27.72 mg/g at pH from 3 to 4,which would decrease with the pH out of this range.Chloridion had no appreciable impact on the defluoridation process,but the F-adsorption was obviously influenced by sulfate ions and phosphate ions,and the higher the concentration the greater the effect.Scanning electron microscope and X-ray spectrometer showed that fluorine content gradually reduced along with the increase of depth of particles,which indicated that the mass transfer process of fluorinion inside the particle was blocked.SEM-EDS data also showed that the interference of sulfate ions and phosphate ions on defluoridation mainly occurred on the particle surface.