方解石对水中磷的去除效果研究

以60~100目天然方解石为实验材料,通过对不同浓度磷的去除效果实验和动态实验研究了其对磷的去除性能,并研究不同pH值下方解石对磷的去除效果。对不同pH值下方解石对800 mg/L磷的去除效果研究结果表明,pH对去除效果影响较大,在初始pH值为4.9(平衡pH值为6.4)时去除率最高,对磷的去除率达到31%;对pH范围4.5~4.8内不同浓度的磷的去除效果实验表明,方解石对高浓度的磷去除效果较好,对100 mg/L的磷去除率为20%,对1 600 mg/L的磷去除率达到49%。在酸性条件下,方解石对磷的去除机理为Ca2+与HPO24-的化学沉淀过程。动态实验表明,填充高度为25.4 cm及填充直径为10 cm时,方解石对流速为66.85 mL/min,浓度为100 mg/L磷的去除效果较差,5 min时出水去除率为64%,再生后对磷的去除效果较好,前10 min去除率在90%以上,理论最大去除量提高了53%。

Removal of phosphorus from aqueous solution by natural calcite

The characteristics of phosphorus removal by natural calcite (grain size between 60 and 100 meshes) were studied in the laboratory with batch and column experiments. The results showed that the initial pH affected the removal rate of phosphorus by calcite significantly. The removal rate of phosphorus at the concentration of 800 mg/L was highest at initial pH 4.9, and the removal rate was 31%.The further experiments showed that the removal rate increased with phosphorus concentration, and the maximum removal rate was 49% at phosphate concentration of 1 600 mg/L. The analysis of the Ca²⁺ activity in solution and the XRD diagram showed that the phosphorus removal mechanism was the precipitation of Ca²⁺ and HPO^2-₄ under acidic conditions. The dynamic column experiments showed that the removal efficiency of phosphorus was not well at flow rate of 66.85 mL/min and phosphate concentration of 100 mg/L when the calcite was filled 25.4 cm in a column with a diameter of 10 cm. The removal rate arrived 64% in 5 min. The removal efficiency increased by 53% after regeneration of calcite by 3% HCl, and the removal rate kept above 90% in 10 min.