高岭石胶体的降氟作用机理  

Defluoridation of Kaolinite Colloid

作　　者：王洪涛[1] 刘连文[1] 

机构地区：[1]南京大学地球科学系表生地球化学研究所成矿作用国家重点实验室,南京210093

出　　处：《南京大学学报（自然科学版）》2002年第6期855-859,共5页Journal of Nanjing University（Natural Science）

摘　　要：含氟溶液的高岭石吸附实验表明,其吸附能力与溶液的pH值呈现显著的负相关关系.在酸性条件下,高岭石的吸氟量较大,降氟率较高;随着pH值的增大,其吸氟能力大大降低;而在碱性条件下,高岭石基本不具有吸氟能力.高岭石的吸氟量还受高岭石用量和含氟溶液浓度的影响.高岭石吸附氟主要是由于体系pH值降低,高岭石表面带正电荷而吸附F-离子;另外,随着NaF浓度的提高,体系ξ电势减小,发生絮凝作用,高岭石携带F-离子沉淀下来.The kaolinite adsorption experiments were conducted on the fluoride solution. Results show that an excellent negative correlation exists between the adsorption ability of kaolinite and pH values of the solution. Kaolinite adsorbs more fluorine ions and the defluoridation effect is remarkable at low pH value; As pH value increases, the amount of fluorine adsorbed by kaolinite decrease rapidly; even worse, kaolinite seldom adsorbs fluorine ions in basic solution. The amount of kaolinite and the concentration of fluoride solution also influence the amount of fluorine adsorbed on kaolinite. This is believed to be the result of a positive surface charge build-up on the kaolinite at low pH that causes affinity of the negatively charged fluoride ions. In addition, as the concentration of the fluoride solution increases, the potential falls, resulting in flocculation of kaolinite together with fluoride ions.

关 键 词：高岭石胶体 降氟作用 PH值 降氟机理 吸氟能力 饮水净化 

分 类 号：TU991.266[建筑科学—市政工程]