摘要： 采用胶体滴定法对循环水中改性聚羧酸盐TH-2000电荷密度进行测定，探讨了pH、滴定速度对电荷密度的影响，确定了最佳滴定条件。研究了循环水中共存物质对测定结果的影响，当Na⁺<350 mg/L、Cl^-<350 mg/L、SO₄^2-<270 mg/L、PO₄^3-<50 mg/L、Fe²⁺<1 mg/L、Zn²⁺<3 mg/L时，对测定结果基本无影响，水质稳定剂（NaPO₃）₆<10 mg/L、ATMP<20 mg/L、HEDP<50 mg/L、DTPMPA<30 mg/L、BTA、MBT、TTA<5 mg/L时，测定影响可以忽略，Ca²⁺、Mg²⁺的影响可通过加入EDTA二钠进行掩蔽。该法准确、实用性强，检出限为0.096 mmol/L。

关键词: 聚二甲基二烯丙基氯化铵, 胶体滴定法, 改性聚羧酸盐TH-2000, 电荷密度

Abstract: The charge density of TH-2000 in circulating water has been determined by colloid titration method. The influences of pH and titration speed on charge density are discussed,the optimal determination conditions de-termined,and the influences of coexisting substances on the determination results of charge density researched. When the concentrations of inorganic ions in circulating water are as follows:Na⁺<350 mg/L,Cl^-<350 mg/L,SO₄^2-< 270 mg/L,PO₄^3-<50 mg/L,Fe²⁺<1 mg/L,Zn²⁺<3 mg/L,there is not any effect on the determination results.When the concentrations of water quality stabilizers in circulating water are as follows:(NaPO₃)₆<10 mg/L,ATMP<20 mg/L, HEDP<50 mg/L,DTPMPA<30 mg/L,BTA,MBT,TTA<5 mg/L,the influences on determination can be neglected. The influences of Ca²⁺ and Mg²⁺ can be sheltered by adding a certain amount of EDTA-2Na. This method is accu-rate,practical and its detection limit is 0.096 mmol/L.

Key words: poly-dimethyl diallyl ammonium chloride, colloid titration, modified poly-carboxylate TH-2000, charge density

中图分类号: 

• X703.1