锌对含磷废水化学特性的影响

EFFECT OF ZINC ON CHEMICAL CHARACTERISTICS OF PHOSPHATIZING WASTEWATER

涂装行业锌系磷化工艺产生含锌磷化废水。本文研究采用Fe2(SO4)3和CaCl2为沉淀剂处理该种废水时,锌对溶液中磷的化学特性的影响。以化学法处理废水时,锌引起金属磷酸盐沉淀的pH发生变化,比理论计算值偏高。以CaCl2为沉淀剂处理锌系磷化废水时,除磷的最佳pH大于10.72,高于Yonghui Song等人用纯磷酸盐和纯钙盐反应得出的最佳pH值7.0～9.0;而除锌的pH值大于8.00,采用CaCl2处理废水能同时达到去锌除磷的要求。以Fe2(SO4)3处理废水时,除磷最佳pH为4.10,高于理论计算值3.18。

For a new technological process which generates the wastewater containing both phosphorus and zinc, the research on the effect of zinc on the chemical characteristics of phosphatizing wastewater possesses an important significance. In this study, Fe3（SO4）2 and CaCl2 were used as precipitators to treat the phosphatiz/ng wastewater. The results showed that, when TP concentration in influent water was 15.67mg/L, without any precipitator, adjust pH to 12.10 with NaOH, TP concentration in effluent water was 9.53 mg/L,when Fe （SO4）2 was used as precipitator, TP in influent water was 11.97 mg/L, while TP in effluent water was 0.44 ~0.26mg/L; the optimum pH for phosphorus removal ranged 3.04～5.50; when CaCI2 was use as precipitator, TP in influent water was 12.24mg/L, while phosphorus concentration in effluent water was less than 0.47mg/L; the optimum pH for phosphorus removal and zinc removaI were over 10.72 and over 8.00 respectively; thus, under the alkaline condition, the process could reach the requirements of phosphorus and zinc removal concurrently.