连续式泡沫分离器深度处理胶团强化超滤渗透液中的SDS和Cd^(2+)

Surfactant SDS and Cd^(2+) recovery from permeate in MEUF using a continuous foam fractionator

利用泡沫分离技术,对胶团强化超滤(MEUF)工艺处理含SDS和Cd2+所得渗透液中SDS的回收进行了研究,考察了影响表面活性剂SDS(十二烷基硫酸钠)和金属Cd2+去除率,富集率及夹带率的操作参数(空气流速?泡沫高度?液面高度),溶液体系性质(表面活性剂SDS进料浓度、pH值、离子强度和乙醇的添加量)等因素对分离效果的影响.实验结果表明,当胶团强化超滤废水中初始SDS和Cd2+的浓度为1440mg·L-1和50mg·L-1时,排出的渗透液中含SDS和Cd2+浓度分别为500mg·L-1和10mg·L-1,在最佳的工艺条件下(曝气头孔径为10μm,空气流速为100L·h-1,液体流速为5L·h-1,泡沫高度为66cm,液面高度为45cm),SDS和Cd2+的去除率分别达52%和99.35%,SDS富集比为3.1.Cd2+出水浓度低于0.1mg·L-1,达到GB8978-1996国家污水排放标准.

The purpose of this study was to investigate the use of foam fractionation to recover surfactant SDS and Cd^2＋ from micenar-enhanced ultrafiltration （MEUF） permeate. The effects of air flow rate,liquid-and vapor-phase heights ,liquid feed surfactant concentration, solution pH, suspension ionic strength, and concentration of ethanol on separation characteristics were studied in continuous operation. The results showed that when the concentration of surfactant （SDS） and metal ions （ Cd^2＋ ） in the feed solution were 500 m·L^ -1 and 10 m·L^ -1, optimum conditions were air and liquid flow rates 100 L·h^- 1 and 5L·h^- 1, liquid- and vapor- phase heights 45 cm and 66 cm,respectively,sparger （pore size 10 μm）. Under the optimum conditions,the about 52% SDS and 99.35% Cd^2＋ were removed. The enrichment ratio of SDS was 3.1 and Cd^2＋ in the effluent was less than 0. 1 mg·L^-1 ,which meets the top grade national discharge standard.