真空膜蒸馏和膜吸收耦合处理电镀废水

TREATMENT OF ELECTROPLATING WASTEWATER BY COUPLING VACUUM MEMBRANE DISTILLATION AND MEMBRANE GAS ABSORPTION

采用疏水聚四氟乙烯（PTFE）中空纤维膜对高盐有机电镀废水进行真空膜蒸馏（VMD）和膜吸收（MGA）实验。结果表明,在VMD中,曝气可提高产水通量,当曝气量超过2 m3/（m2·h）时,产水通量趋于稳定;随着料液温度和真空度的提高,产水通量显著增加。连续180 d运行实验表明,产水通量保持在2.4～2.6 kg/（m2·h）,产水指标除NH3-N含量以外,均达到GB 8978-1996排放二级标准。MGA脱氨实验表明,当产水p H和流速分别为10.5和0.20 m/s,吸收剂浓度和流速分别为0.2 mol/L和0.20 m/s时,在30 min内可将NH3-N的质量浓度从270 mg/L脱除至10 mg/L以下,产水指标达到污水综合排放标准。

Treatment of electroplating wastewater with high-concentration salts and organics by coupling vacuum membrane distillation （VMD） and membrane gas absorption （MGA） using the PTFE hollow fiber membrane was investigated. The results showed that the permeate flux increased with an increase of air blowing intensity. When the air blowing intensity was greater than 2m3/（m2·h）, the permeate flux maintained at a stable level. Meanwhile, the permeate flux significantly increased with the increase of feed temperature and vacuum. The continuous tests in 180 d showed that the permeate flux range from 2.4 to 2.6 kg/（m2·h） and the permeate indexes met the Second Grade Standard of GB 8978-1996 except the content of NH3-N. The results of MGA experiment showed that the mass concentration of NH3-N decreased from 270 mg/L to 10 mg/L in 30 min when the permeate pH, permeate velocity, absorbent concentration and velocity were 10.5, 0.20 m/s, 0.2 mol/L and 0.20 m/s, respectively. The permeate indexes met the Second Grade Standard of GB 8978-1996 and could be discharged safely.