水洗废啤酒酵母去除电镀废水中镉的工艺试验研究

Experimental Investigation on Removing Cadmium from Electroplating Wastewater by Water-Washing Process with Waste Saccharomyces cerevisiae

以水洗废啤酒酵母为吸附剂,采用自制试验装置,对电镀废水中重金属镉进行吸附-沉降工艺试验研究.结果表明,在废水处理量1L,废水中镉质量浓度为26mg/L,pH=7,吸附剂用量40g/L(湿重),室温约25℃,搅拌速度1000r/min,吸附时间30min,沉降240min的条件下,废水中镉的吸附率及吸附—沉降后镉的去除率分别达96.59%和94.25%.三级处理后废水中镉达到排放标准(<0.1mg/L).连续处理效果比间歇处理效果略差.采用扫描电子显微镜及表面能谱,分析了水洗废啤酒酵母对镉的吸附机理.结果表明,水洗废啤酒酵母对镉的吸附过程中细胞结构受到破坏,吸附过程有化学络合和静电吸附作用存在.

The biosorption-sedimentation process for removing the heavy metal cadmium from electroplating wastewater was experimentally investigated taking the waste Saccharomyces cerevisiae as biosorbent on a self-making experimental setup. The results showed that biosorption rate and removed rate of Cd are 96.59% and 94.25% respectively on conditions that wastewater processed is 1 L,Cd concentration in the wastewater about 26 mg/L,pH value 7.0,the dose of the waste Saccharomyces cerevisiae 40 g/L（in wet weight）,at room temperature about 25 ℃,stiring speed 1 000 rpm,adsorbing time 30 min and time for natural sedimentation 240 min. The Cd concentration in wastewater after three-step biosorption comes up to china＇s national standard on effluents（0.1 mg/L）. With respect to the processing effect,the continuous process is relatively poorer than the intermittant one. The biosorption mechanism of the water-washing process with waste Saccharomyces cerevisiae for Cd removal was analyzed by SEM and EDS. The results showed that the cell structure of the bacteria used is destroyed in such a water-washing process,and the effects of chemical complexing and electrostatic adsorption are found in the biosorption process.