新型饮用水除氟材料Bio-F的除氟特性和比较研究

Characteristics and Comparative Study of a New Drinking-Water Defluoridation Adsorbent Bio-F

对3种传统除氟剂活性氧化铝、骨炭和改性沸石与自制的新型生物除氟剂Bio-F的除氟性能及影响因素（材料粒径、pH值、吸附时间、水样含氟浓度、其它离子、再生能力等）进行了比较,并模拟动态实验评估了这4种除氟材料对实际高氟地下水处理的效果.结果表明,Bio-F生物除氟剂对F-的吸附过程符合Lagergren一级吸附动力学特征（R2=0.958 0）,吸附速率较快,且该过程属于吸热反应;Bio-F吸附F-符合Langmuir吸附等温模型（R2=0.999 2）,吸附容量高,静态吸附容量可达4.088 3mg.g^-1,分别约是活性氧化铝和改性沸石的1.8和5.8倍.4种除氟材料吸附容量与氟浓度正相关,与吸附剂粒径负相关.高浓度的CO3^2-、HCO3^-明显抑制Bio-F的除氟（p〈0.05）,但高浓度的Ca^2＋、NO3^-、HPO4^2-有利于Bio-F的除氟（p〈0.001）.Bio-F除氟最佳停留时间3-4 min,远远低于沸石20 min和活性氧化铝11 min.在pH 4.0-9.0范围内Bio-F可保持90%以上吸附F-的能力.再生性能稳定,10次再生后吸附容量变化不超过15%.Bio-F综合性能优于其它3种传统除氟剂,在我国广大农村地区推广有显著优越性.

To evaluate the application potentiality of a new type drinking-water defluoridation adsorbent Bio-F, comparative study on the defluoridation characteristics of common adsorbents activated alumina （AA）, bone char （BC）, activated clinoptilolite （AC） with Bio-F was conducted. The defluoridation characteristics under different conditions, such as particle diameter, pH, retention time, fluorine concentration, regeneration stability, were investigated by continuous-flow column experiments and static tests. The defluoridation efficiency of high fluoride underground water by four types of adsorbents was also compared. The results showed that F- adsorption kinetics of Bio-F fitted the Lagergren First-order equation （R^2 = 0.958 0）. F- adsorption by Bio-F was found to fit the Langmuir adsorption isotherm （R^2 = 0.999 2）. The results indicated that the static defluoridation capacity （DC） of Bio-F was 4.088 3 mg·g^-1 , which was about 1.8 folds and 5.8 folds of those of AA and AC respectively. DC of all four adsorbents was positively correlated with F^- concentration and negatively correlated with particle size. High concentration of CO3^2- and HCO3^- reduced the DC of Bio-F （p 〈 0.05 ）, while high concentration of Ca^2＋ , NO3^- , HPO4^2- favored defluoridation by Bio-F （p 〈0.001）. The optimal retention time of Bio-F was 3-4 rain, which was less than that of AC （20 min） and AA （11 min）. The DC of Bio-F remained relatively stable in pH 4.0-9.0 and in regeneration since the DC variation was not more than 15%. The above results indicated that Bio-F was superior to AA, BC and AC in drinking-water defluoridation.