内循环泡沫浮选塔间歇分离含镉废水

Treatment of Cd^(2+)-containing wastewater by internal circulation foam floatation tower

为强化气液传质,提出了泡沫塔对泡沫分离性能影响的研究,并为此设计了在泡沫塔内加内循环套筒的泡沫分离塔。结果表明,与没有加内循环套管的常规塔相比,通过FT-IR检测分析,内循环塔性能明显优于常规塔。在间歇分离条件下,研究在内循环塔内处理含镉废水,探讨pH、LAS、停留时间、气泡大小等因素对镉去除率的影响。确定最佳处理条件为:pH=4.0,LAS=65 mg/L,塔内停留时间大于20 min,气体流量为250 mL/min,在此最佳实验条件下,镉的去除率可达99.9%以上,此时的镉质量浓度为10 mg/L。表面活性剂协同效应实验结果表明,在加入阳离子表面活性剂十二烷基二甲基苄基溴化铵时,会形成一个二元表面活性剂协同效应区。

To strengthen the efficiency of gas-liquid mass transfer, a study was carried out concerning the influence the foaming tower on the function of foam separation ; therefore, an inner loop sleeve was designed to be put inside the foaming tower. The results prove that the foaming tower with inner loop sleeve has functioned much well than without through the detection and analysis of FT-IR. Through batch distillation and separation,the cad- mium wastewater was put into this newly-designed foaming tower and analyzed on pH, LAS, retention period, bub- ble size etc. to see how these factors affect the removal rate of cadmium. The optimum treatment conditions are as follows ： pH = 4.0, LAS = 65 rag/L, the retention period of more than 20 minutes inside the tower, the gas flow of 250 mL/min. Under these optional experimental conditions, the removal rate of cadmium can reach 99.9% when the mass concentration of cadmium is 10 mg/L. As a result of the experiment on the synergy of the surfactant, when the cationic surfactant dodeey dimethyl benzyl ammonium bromide （DDBAB） was added into the tower,a synergistic effect zone of binary surfactants was formed.