Situation of fluoride contamination in well waters in Sri Lanka, and removal of fluoride by chicken bone char

在斯里兰卡的干旱地区，如中北部省和东南部省，井水中的氟化物浓度高到足以引起氟牙症和氟骨症。在本研究中，我们对全国1300口井水进行了测量，以确定井水的氟化物浓度。根据分析结果，绘制了氟化物空间分布图。为去除井水中的氟化物，采用600℃热解1小时制得鸡骨炭（CBC）。斯里兰卡丹布拉市的一个家庭操作了装有CBC的除氟过滤器，以确认过滤器的性能。结果表明，含有560g CBC的过滤器可以处理1400 L井水，相当于一个4口之家140天的平均用水量。在一级反应的基础上，建立了能较好地再现处理水中氟化物浓度的动力学模型。

In the dry zone of Sri Lanka, such as north central province and southeast province, fluoride concentration in the well water is high enough to cause dental fluorosis and bone fluorosis. In this research, we measured 1300 well waters to determine the fluoride concentration of the well water in the whole counry. According to the analytical result, a spatial distribution map for fluoride was created.To remove fluoride from well water, chicken bone char(CBC) was produced by pyrolysis at 600 C for 1 hour. Fluoride removal filter packed with CBC was operated by a family in Dambulla city of Sri Lanka to confirm the performance of the filter. It was revealed that 1400 L of the well water, which is equivalent to the averaged consumption of water for 140 days in a family with 4 person, could be treated by the filter containing 560 g of CBC. A kinetics model, which reproduced the fluoride concentration of treated water quite well, was established based on the first-order reaction.