羟基磷灰石/活性炭复合吸附剂的制备及其除氟性能研究

采用羟基磷灰石(HAP)和活性炭(AC)共混,经过活化烧结制得HAP/AC复合吸附剂.考察了HAP/AC质量比、聚乙烯醇(PVA)浓度、焙烧时间和焙烧温度等因素对吸附剂去除水中氟离子的影响.实验结果表明:HAP/AC质量比为4∶1、PVA浓度3wt;、焙烧温度350 ℃、焙烧时间3.5 h,吸附剂对氟离子的去除效率达到最大值为70.69;.将HAP/AC复合吸附剂用于对模拟含氟废水的吸附研究,通过静态吸附实验和动态柱吸附实验考察了吸附剂对模拟含氟废水的吸附性能,对其吸附机理进行了探讨.结果表明Langmuir等温吸附模型更优于Freundlich模型,且吸附剂对氟离子的吸附主要以表面单分子层吸附为主,吸附过程中具有离子交换能力的活性中心起主导作用.最后将HAP/AC复合吸附剂应用于地氟病区实际含氟废水的处理,以探讨其实际运用的可行性.

Fabrication of Hydroxyapatite/Activated Carbon Composites Adsorbents and Its Absorption Property for Fluoride

Hydroxyapatite/activated carbon (HAP/AC) composites adsorbents were fabricated by blend with hydroxyapatite and activated carbon following activation and calcination.The effects of the HAP/AC mass ratio, polyvinyl acetate concentration, calcination time and temperature on adsorption efficiency were investigated.The results show that the optimal conditions were happened in HAP/AC (mass ratio) 4∶1, PVA concentration 3wt%, calcination temperature 350 ℃ and calcination time 3.5 h, producing fluoride adsorption efficiency to 70.69%.The adsorption property of HAP/AC adsorbents toward simulative fluoride waste water by static adsorption and dynamic column adsorption were investigated, moreover the mechanism of the adsorption process was determined.The results show that the fitness of adsorption data by Langmuir model is superior to Freundlich model.Surface monolayer adsorption are dominated in the adsorption of fluoride, and active center with ion-exchange capacity play a leading role in adsorption process.At last, field studies were carried out with the fluoride containing water sample collected from a fluoride-endemic area in order to test the suitability of the adsorbents at field conditions.