Graduate Program in Chemical Engineering, Federal University of Santa Catarina, Florianópolis, Brazil.
Department of Engineering, Federal University of Santa Catarina, Blumenau, Brazil.
Environ Technol. 2020 Jul;41(17):2253-2265. doi: 10.1080/09593330.2018.1561758. Epub 2019 Jan 2.
The reuse of treated dyeing wastewater has become a viable option to minimizing water scarcity problems and environmental impacts in the textile industry. The potentiality of commercial flat sheet membranes of polytetrafluoroethylene (PTFE) and polypropylene (PP) in direct contact membrane distillation (DCMD) for dye synthetic solution treatment has been explored in this work. DCMD is interesting for the textile industry since a recovery of heat by hot dyeing wastewater for thermal energy is possible. Moreover, DCMD enables water and dye reclamation with possible reuse in the textile process. The commercial availability of membranes may expedite the DCMD commercialization in the textile industry. Experiments were conducted in a laboratory-scale circulating unit with synthetic solutions containing reactive or disperse dye. High mean permeate flux up to 18.8 kg m h with complete colour rejection was obtained. The dyes tested in this study are not able to completely wet the membranes and the increase of the permeate flux when compared to distilled water is attributed to electrostatic interactions between the dyes and the membranes. Moreover, a partial wetting reduced vapour diffusion path and the permeate flux was increased. PP membrane showed higher performance due to higher porosity when compared to the PTFE membrane. In addition, an influence of dye class on permeability was observed. The results were promising when compared to other studies, which used commercial or lab-scale membranes.
处理后的染色废水再利用已成为纺织工业解决水资源短缺和减少环境影响的可行方案。本工作探讨了商业聚四氟乙烯（PTFE）和平板聚丙烯（PP）膜在直接接触式膜蒸馏（DCMD）中处理染料合成溶液的潜力。DCMD 对于纺织工业很有吸引力，因为可以回收热染色废水的热量以获取热能。此外，DCMD 可实现水和染料的回收，并可在纺织工艺中再利用。膜的商业可用性可能会加速 DCMD 在纺织工业中的商业化。实验在带有合成溶液（含活性或分散染料）的实验室规模循环装置中进行。采用高平均渗透通量可达 18.8kgm-2h-1，且颜色去除率达到 100%。本研究中测试的染料不能完全润湿膜，与蒸馏水相比，渗透通量的增加归因于染料与膜之间的静电相互作用。此外，部分润湿减少了蒸汽扩散路径，从而提高了渗透通量。与 PTFE 膜相比，PP 膜由于其更高的孔隙率，表现出更高的性能。此外，还观察到染料类别对渗透性的影响。与使用商业或实验室规模膜的其他研究相比，结果很有前景。
