Fabrication of high-performance PVA/PAN composite pervaporation membranes crosslinked by PMDA for wastewater desalination

The pyromellitic dianhydride（PMDA） crosslinked poly（vinyl alcohol）（PVA） was coated on top of the PAN ultrafiltration membrane to form a PVA/PAN composite PV membranes for wastewater desalination. The composite membranes have high application value in industrial wastewater treatment. By varying the membrane fabrication parameters including the weight percent（wt%） of the PMDA, the crosslink temperature and duration, membrane with the best desalination performance was obtained. The composite membrane with a 2-lm-thick PVA selective layer containing 20 wt% of PMDA and being crosslinked at 100 °C for 2 h showed the highest Na Cl rejection of 99.98% with a water flux of 32.26 L/（m^2 h）at 70 °C using the 35,000 ppm Na Cl aqueous solution as feed. FTIR spectroscopy, wide-angle X-ray diffraction, thermogravimetric analysis and scanning electron microscope have been used to characterize the structures and properties of both the crosslinked PVA dense films and PVA/PAN composite membranes. The effects of the concentrations of PMDA,the crosslinking time and temperature to the membrane water contact angle, swelling degree, salt rejection and water flux were systematically studied.

新型移动床膜生物反应器处理PVA废水的实验研究

将移动床生物膜反应器（MBBR）与膜生物反应器（MBR）有机结合，形成一体化式新型移动床膜生物反应器（M—MBBR）。采用M—MBBR对PVA废水的处理效果进行了研究，介绍了反应器的结构，并考察了水力停留时间、COD容积负荷及曝气量等操作条件对处理效果的影响。实验结果表明，在水力停留时间8h，气水比为120：1，COD容积负荷在1．4—2．8kg／（m^3·d）范围内变化时处理效果最佳且出水保持稳定。在此操作条件下，M—MBBR对PVA和COD的去除率可分别达到54％和69％左右。

动态陶瓷膜对PVA退浆废水处理效果的研究

以陶瓷膜作为载体,高岭土作为涂膜材料制备动态膜,研究了自生动态膜处理含PVA退浆废水的膜分离特征,确定了最佳涂膜浓度,并考察了跨膜压差、错流速度以及温度等操作条件对膜通量的影响,为进一步的工业放大设计提供了基础数据。

尽快推行环保上浆 切实降低印染废水COD

文章指出PVA用于纺织上浆,排放很难生物降解的COD,是造成当前印染污水难以达标的主要原因。简述了"环保上浆"已不存在技术问题、推行"环保上浆"的措施及"环保上浆"节能减排的效果。对比了末端治理工艺路线和源头治理工艺路线。