聚合铁钛混凝剂对印染废水的处理

采用钛铁矿为主要原料，以硫酸溶出部分铁和钛，并调节Ti/Fe比、碱化度制备高效的新型含钛聚合硫酸铁混凝剂(T-PSF)，将其用于分散兰和活性黄2种模拟印染废水的脱色处理并研究其混凝去除机理。实验结果表明，在Ti/Fe为1∶6和碱化度为2.0时，制备出的T-PSF混凝效果最好。T-PSF对分散兰的去除率为94.3%，比FeCl3的去除率提高53.8%；对活性黄的去除率为34.0%，比FeCl3提高12.7%。T-PSF处理分散兰和活性黄的最佳投加量均为0.3 mmol·L-1，最佳水样初始pH分别为6和8。絮体粒径及结构分析结果表明，T-PSF处理分散兰过程中形成的絮体粒径较FeCl3大，处理活性黄过程中所形成的絮体粒径较FeCl3小，但絮体结构均比FeCl3更密实。结合T-PSF的表征、Zeta电位及絮体特性分析表明，在分散染料去除过程中，T-PSF产生的多羟基钛铁聚合物的电中和及吸附架桥起主要作用；对于活性染料的去除，主要机制为T-PSF水解产生的带正电的多羟基钛铁聚合物的吸附络合作用。

Treating dyeing wastewater with a kind of polyferric titanium sulfate

In this study, a new polyferric-titanium sulfate coagulant (T-PSF) was prepared through dissolving a part of iron and titanium from ilmenite with sulfuric acid and adjusting Ti/Fe ratio and basicity. The T-PSF was used to treat two kinds of simulated dye wastewater (disperse blue and reactive yellow), and its coagulation mechanisms were also discussed. The results showed that T-PSF had a good coagulation performance with the Ti/Fe ratio of 1∶6 and basicity of 2.0. The removal efficiencies of disperse blue and reactive yellow by T-PSF coagulation were 94.3% and 34.0%, which were 53.8% and 12.7% higher than those by FeCl3 coagulation, respectively. For disperse blue and reactive yellow removal, the optimal T-PSF dosages were 0.3 mmol·L-1 and the optimum pHs were 6 and 8, respectively. In compared with flocs during FeCl3 coagulating dyes, larger and more compact ones occurred during T-PSF coagulating disperse blue, while smaller and more compact one occurred during T-PSF coagulating reactive yellow. In combination with T-PSF characterization, Zeta potential and other properties of flocs, charge neutralization and bridging of polyhydroxy-ferrotitanium polymers through T-PSF hydrolysis were identified as playing a key role in disperse dyes removal, while the adsorption and complexation of positively charged polyhydroxy-ferrotitanium polymers through T-PSF hydrolysis were identified as playing a key role in reactive dyes removal.