酒糟生物炭负载铝对饮用水中氟的去除

Removal of fluoride from drinking water using distiller's grains biochars coated by aluminum hydroxide

以酒糟生物碳为原料,采用负载Al(OH)_3改性制得生物吸附剂(CDGB)。通过静态吸附实验研究吸附剂用量、初始浓度、吸附时间、pH值和共存离子对CDGB吸附氟能力的影响。结果表明:CDGB具有非常宽的最适pH值范围,在pH值为5.0~9.0范围内CDGB均能有效地去除饮用水中的氟离子;并且在氟初始浓度为10 mg·L^(-1),吸附时间40 min,CDGB的添加量为2 g·L^(-1)时氟的去除率可达90%以上,且吸附后水中氟离子含量低于1 mg·L^(-1),符合国家饮用水标准;溶液中常见的共存离子(硝酸根、氯离子和硫酸根)对吸附剂吸附没有显著影响;CDGB对氟离子吸附过程符合Langmuir吸附等温线模型和伪二级吸附动力学模型,理论饱和吸附容量为18.05 mg·g^(-1)。

A new type of adsorbent was prepared by loading Al（ OH）3on distiller’s grain biochar for the removal of fluoride from drinking water. Key factors,including adsorbent dosage,initial fluoride concentration,contact time,and initial pH of the biosorbent,were investigated to evaluate the efficiency of fluoride removal. The solution pH played an important role in the removal of fluoride,and distiller ’s grain biochar loaded with Al（ OH）3（ CDGB） showed the most potential for use as a biosorbent to remove fluoride from drinking water across a wide pH range from 5. 0 to 9. 0. The fluoride concentration could be reduced to below 1 mg·L-1from an initial fluoride concentration of 10 mg·L-1（ adsorbent dosage of 2 g·L-1,contact time of 40 min）,which was below the Chinese national standard in drinking water. With the exception of bicarbonate,co-existing ions（ nitrate,chloride,and sulfate） did not have a significant effect on the defluoridation process of CDGB. The adsorption process could be described well by the Lagergren pseudo-second-order kinetic model. Fluoride adsorption by CDGB followed the Langmuir isotherm model,and the maximum fluoride adsorption capacity was 18. 05mg·g-1.