表面活性剂复配体系浮选去除废水中铜离子的研究

Research of Removing Copper from Wastewater with Mixed Surfactants by Flotation

对阴离子表面活性剂十二烷基硫酸钠和非离子生物表面活性剂茶皂素进行了复配,同时也将十二烷基硫酸钠与另一种非离子化学表面活性剂吐温80复配作为对照,分别讨论了这两种复配体系浮选去除废水中铜离子(Cu2+)的能力。实验中考察了溶液初始pH值、C复配体系/CCu2+(摩尔比)、离子强度(NaCl和NaNO3)这些物理因素和动力学参数(浮选时间和通气量)对Cu2+去除率和富集比的影响。结果表明,在相同的实验条件下,采用十二烷基硫酸钠与茶皂素复配体系浮选去除废水中Cu2+的效果比对照组的明显要好。在十二烷基硫酸钠与茶皂素复配比为0.8∶0.2,C复配体系/CCu2+=3∶1,pH=8,通气量为0.2L·min-1的条件下可以得到94.8%的最大去除率,泡沫浓缩液中铜的富集比最高达158。随着溶液中离子强度的增大,Cu2+去除率明显降低。采用碱沉淀法回收泡沫浓缩液中的Cu2+,回收率达到了86.4%。

The potential of the complex system consisted by anionic surfactant （sodium dodecyl sulfate, SDS） and nonionic biosurfactant （tea saponin, TS） to remove copper from wastewater was investigated. The control group mixed by SDS and the other nonionic chemical suffactant Tween-80 was set as well. Main physicochemical parameters influencing process,such as the collector-copper ratio （molar ratio ）, pH of the solution, the ionic strength （NaCl and NaNO3）, as well as kinetic parameters （flotation time and air flow rate） were evaluated. Promising results were obtained. Under identical conditions, the rate of copper removed by the complex of SDS and TS was significantly higher than by the control group. The removal efficiency increased with increasing molar fraction of SDS to TS and reached to maximum when mixture ratio was 0.8： 0.2. The maximum value of removal rate and enrichment ratio was 94.8% and 158 respectively when the collector-copper ratio was 3：1, pH was 8, and air flotation was 0.2 L·min^-1. Ionic strength had a remarkable impact on copper removal. Copper removal rate significantly decreased with increasing of inorganic salt concentration from 10^-4 mol·L^-1 to 10^-2 mol·L^-1 when copper concentration in solution was invariable. Copper recovery rate with alkaline precipitation could reach up to 86.4% when copper concentration in foam concentrated was higher than 50 mg·L^-1.