螺蛳壳和鱼骨混合物对水中磷酸盐的去除作用

Effect of Bellamya-quadrata-Shells-and-Fish-Bones Mixture Removing Phosphate in Water

通过试验研究了螺蛳壳、鱼骨以及螺蛳壳和鱼骨混合物对水中磷酸盐的去除作用。结果表明,当磷酸盐初始质量浓度C0为20 mg·L-1、pH值为7、T为303 K条件下,螺蛳壳投加量为4 g·L-1时对水中磷酸盐的去除率在36 h时达最大值86%;鱼骨投加量为2 g·L-1时,在不存在钙离子的情况下鱼骨对磷酸盐的去除率较低,当反应时间为5 h时仅为36%左右;螺蛳壳和鱼骨混合物可以有效去除水中的磷酸盐,特别是较短时间内(12 h以内)其去除能力明显优于单独投加螺蛳壳或鱼骨,投加量为6 g·L-1时其对水中磷酸盐的去除率在12 h时达最大值96%。pH值,水中共存的Cl-、SO42-、Na+、K+和Mg2+对螺蛳壳和鱼骨混合物去除水中磷酸盐的影响较小,HCO3-会抑制螺蛳壳和鱼骨混合物对水中磷酸盐的去除,而Ca2+则会促进螺蛳壳和鱼骨混合物对水中磷酸盐的去除。螺蛳壳和鱼骨混合物对水中磷酸盐的主要去除机制包括螺蛳壳和鱼骨对磷酸盐的表面吸附作用以及钙磷化合物沉淀作用。鱼骨可以为钙磷化合物沉淀的异质成核提供核心,促进钙磷化合物沉淀的生成;螺蛳壳和鱼骨所释放出来的钙离子可以为钙磷化合物沉淀的形成提供钙源。

Abstract： An experiment was conducted to study effects of Bellamya quadrata shells, fish bones arid mixture of Bellamya quadrata shells and fish bones removing phosphate in water. Results show that in water, 20 mg·L-1 in initial phosphate concentration, 7 in pH and 303 K in T, the phosphate removal rate by Bellamya quadrata shells （4 g·L-1） reached as high as 86% after 36 hours of exposure ; the phosphate removal rate by fish bones （ 2 g·L-1 ） was comparatively low in the absence of Ca2＋, reaching 36% or so after 5 hours of exposure ; and the phosphate removal rate by the mixture of BeUamya quadrata shells and fish bones （ 6 g ·L-1 ） was significantly higher than Bellamya quadrata shells or fish bones, reaching as high as 96% after 12 hours of exposure. Besides, pH and the existence of C1-, SO42- , Na＋ , K＋ , or Mg2＋ in the water did not show much effect on phosphate removal rate of the mixture, while the existence of HCO3- inhibited the removal, and the existence of Ca2＋ promoted the removal. The chief mechanisms of the mixture removing phosphate include surface adsorption of phosphate on Bellamya quadrata shells and fish bones, and precipitation of calcium phosphate. Fish bones act as cores for heterogeneous nucleation, promoting calcium phosphate precipitation, while Bellamya quadrata shells and fish bones do as Ca source, releasing Ca2＋ to form calcium phosphate that precipitates.