膜分离技术处理印制电路板重金属废水应用研究

PILOT STUDY ON PCB HEAVY METALS WASTEWATER TREATMENT USING UF-RO MEMBRANE SEPARATION PROCES

对印制电路板加工酸洗车间产生的重金属废水调节pH至中性后采用超滤-反渗透工艺进行中试。结果表明,在原废水Cu2+的质量浓度60～160mg.L-1、电导率4.5～6.8 mS.cm-1,SS和TDS的质量浓度分别为60～80和1 600～3 200 mg.L-1时,超滤对浊度和SS的去除率分别为97%和73%,反渗透系统对Cu2+和TDS的去除率分别为99.9%和98.9%,系统产水电导率维持在0.015 mS.cm-1以下,出水水质符合GB/T 11446.1-1997的EW-IV标准。超滤膜运行30 min、反冲洗5 min,跨膜压力未发生明显的变化,膜污染较轻。反渗膜的产水率与TMP呈现明显负相关性,相关系数为-0.986 1。通过在反渗透系统前加入活性炭和石英砂过滤装置,增加反冲洗次数等措施,可以有效控制反渗透膜污染,提高膜使用寿命。该系统运行费用为3.36元.m-3,可节约水资源、回收贵重金属,具有良好的经济环境效益。

In this paper, the PCB industry heavy metal wastewater was treated by Ultrafiltration （UF）-Reverse Osmosis（RO） process after pH adjusting.The results showed that, UF removal of turbidity and SS were 97% and 73%, RO removal of Cu and TDS were 99.9%, 98.9%, while the raw wastewater concentrations were Cu2＋ 60～160 mg.L-1, conductivity 4.5～6.8 mS.cm-1, SS 60～80 mg.L-1, total suspended solids （TDS） 1 600～3 200 mg.L-1. The effluent water met the national electronic grade water standard IV （GB/T 11446.1-1997）; Membrane fouling study showed that UF run with 30 min,backwash with 5 min, trans-membrane pressure （TMP） was not changed significantly. The production rate and TMP of RO membrane water showed significant negative correlation, the correlation coefficient was -0.986 1. In the experiment, the way to prevent RO membrane fouling was adding activated carbon, quartz sand filter and increase the frequency of backwash. The system operating cost was 3.36 yuan.m-3. This system can save a lot of water, recyclable precious metals, reduce the waste of resources. Therefore, the project has good economic and environmental benefits.