胶体滴定法测定循环水中TH-2000的电荷密度

Colloid titration method for the determination of TH-2000 charge density in circulating water

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p H、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、SO_4^(2-)<270 mg/L、PO_4^(3-)<50 mg/L、Fe^(2+)<1 mg/L、Zn^(2+)<3 mg/L时,对测定结果基本无影响,水质稳定剂(NaPO_3)_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,Ca^(2+)、Mg^(2+)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。

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 determined, 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 rag/L, Fe^2＋〈l mg/L, Zn^2＋〈3mg/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 rag/L, BTA, MBT, TTA〈5 mg/L, the influences on determination can be neglected. The influences of Ca^2＋ and Mg^2＋ 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.