改性天然沸石的除氟性能研究

高效除氟材料的应用能降低饮用水中的氟质量浓度.采用静态吸附实验,比较了天然沸石和实验室制得的氢氧化铝、硫酸铝、聚合硫酸铁(PFS)改性天然沸石的除氟性能.结果表明,PFS改性的天然沸石具有良好的除氟效果,静态除氟容量可达25 mg·g~(-1).通过动态吸附试验,进一步探讨了饮用水的氟质量浓度、流速、停留时间、床层高度等因素对PFS改性天然沸石除氟性能的影响.研究发现,原水氟质量浓度越低,最佳除氟停留时间越短,PFS改性天然沸石滤柱床层高度越小.当停留时间为68 s,滤柱床层高度为47 mm时,含氟为5.8 mg·L~(-1)的模拟水样经吸附滤柱后,其氟质量浓度降到0.95 mg·L~(-1),低于国家生活饮用水标准的上限值1 mg·L~(-1).当含氟为4.14 mg·L~(-1)时,停留时间缩短为58 s,最小床层高度为40 mm;含氟为2.5 mg·L~(-1)时.停留时间为47 s,最小床层高度为32 mm,出水即可符合国家生活饮用水标准.因此,可根据不同高氟水地区的氟质量浓度来确定停留时间和床层高度,从而确定材料的适宜用量和流量.

Study on the fluoride removal with zeolite modified by polyferric sulfate

Fluoride can be efficiently removed from the drinking water, and the fluoride removal abilities of zeolites modified by aluminum hydroxide, aluminum sulfate and polyferric sulfate (PFS) are investigated by static absorption experiments in the paper. The PFS-modified zeolite is proved to be the first-rate material with a static saturated capacity of 25 mg·g~(-1), and the influencing fac-tors (initial fluoride concentration, flow rate, retention time and bed height) on the fluoride removal are also investigated by dynamic defluorination experiments. The results suggest that the optimum retention time and bed height decrease upon lowering the initial fluoride concentration. When the retention time and bed height are 68 s and 47 mm, respectively, the fluoride concentration could be decreased from 5.8 mg·L~(-1) to 0.95 mg·L~(-1) by the PFS-modified zeolite, which is lower than the national limit of 1 mg·L~(-1) for drinking water. When the initial fluoride concentration is lower, the retention time and bed height are reduced to 58 s and 40 mm for 4.14 mg·L~(-1), and 58 s and 40 mm for 2.5 mg·L~(-1). The retention time and bed height (I.e. The material dosage and flow rate) should be var-ied according to the initial fluoride concentration in order to generate the eligible drinking water.