碳化硅陶瓷膜处理工业废水的工艺特性研究

摘要

The process characteristics of waste-water treatment and effects of the silicon carbide ceramic membranes were studied for three kinds of industrial waste water,the mixture of diluted phosphoric acid and pulp,monoammonium phosphate slurry and oil-containing cutting fluid by the cross-flow filtration method. The effects of the filtration time and transmembrane pressure on the flux through silicon carbide ceramic membranes were evaluated. And the flushing times for flux recovery were also investigated. The experimental results indicated that when the pore size of silicon carbide ceramin membrane was 0.5 μm,transmembrane pressure was 0.14 MPa,the filtration time was 20 min,the suspended solids contents in the filtrate were 54 mg/L,49 mg/L and 16 mg/L,respectively,meeting the Integrated Wastewater Discharge Standard. The membrane flux decreased with increasing filter time,then kept stable after 16 min. As for the oil containing cutting fluid,the filtation effect was best at 0.2 MPa transmembrane pressure. The contents of oil and suspended solids in the filtrate were 0.78 mg/L and 9.35 mg/L respectively,meeting the emissions standard. The flux of the contaminated ceramic membrane can be recovered from 250 L/(h·m2)to 406 L/(h·m2)with 97% or higher recovery ratio after backflushing for 5 times with the mixture of air and water.%采用错流过滤法研究了碳化硅陶瓷膜对稀磷酸+矿浆、磷酸一铵料浆和含油切削液三种工业废水的处理效果及工艺特性,分析了过滤时间和跨膜压差对碳化硅陶瓷膜膜通量的影响规律,研究了反冲洗次数对碳化硅陶瓷膜通量的恢复规律.实验结果表明:以孔径为0.5 μm的碳化硅陶瓷膜,在跨膜压差为0.14 MPa,过滤时间为20 min的条件下过滤上述三种工业废水,滤液中悬浮物的含量分别为54 mg/L、49 mg/L、16 mg/L,均满足《污水综合排放标准》中的排放标准且膜通量随着过滤时间的延长逐渐下降,在16 min达到平衡;当跨膜压差为0.2 MPa时,碳化硅陶瓷膜对含油切削液的过滤效果最好,滤后水的含油量和悬浮物含量分别为0.78 mg/L和9.35 mg/L,满足排放要求.被污染后的陶瓷膜,利用气水混合反冲洗5次后,膜通量从250 L/(h·m2)恢复至406 L/(h·m2),恢复率达到97%以上.