Li Da-Shuai, Pan Ze, Cai Chao-Chen, Li Ting-Ting, Lou Ching-Wen, Lin Jia-Horng, Ren Hai-Tao
Innovation Platform of Intelligent and Energy-Saving Textiles, School of Textile Science and Engineering, Tiangong University, Tianjin 300387, P. R. China.
State Key Laboratory of Separation Membranes and Membrane Processes, Tiangong University, Tianjin 300387, P. R. China.
Langmuir. 2023 Aug 1;39(30):10601-10610. doi: 10.1021/acs.langmuir.3c01203. Epub 2023 Jul 19.
Although the photocatalytic reduction of Cr(VI) to Cr(III) by traditional powder photocatalysts is a promising method, the difficulty and poor recovery of photocatalysts from water hinder their wide practical applications. Herein, we present that FeCO/BiWO (FeCO/BWO) composites were tightly bonded to modified polyvinylidene fluoride (PVDF) membranes by chemical grafting with the aid of polyvinyl alcohol (PVA) to form photocatalytic composite membranes (PVDF@PVA-FeCO/BWO). The contact angle of PVDF@PVA-FeCO/BWO (0.06 wt % of FeCO/BWO) is 48.0°, which is much lower than that of the pure PVDF membrane (80.5°). Meanwhile, the permeate flux of 61.43 g m h and water flux of 250.60 L m h were observed for PVDF@PVA-FeCO/BWO composite membranes. The tensile strength of composite membranes reached 48.84 MPa, which was 9.8 times higher than that of PVDF membrane. It was found that the PVDF@PVA-FeCO/BWO membrane exhibited excellent photocatalytic Cr(VI) reduction performance under both simulated and real sunlight irradiation. The adsorption for Cr(VI) by PVDF@PVA-FeCO/BWO can reach 47.6% in the dark process within 30 min, and the removal percentage of Cr(VI) could reach 100% with a rate constant value of 0.2651 min after 10 min of light exposure, indicating a synergistic effect of adsorption and photoreduction for Cr(VI) removal by the composite membrane. The PVDF@PVA-FeCO/BWO membrane had good stability and reusability after seven consecutive cycles. Most importantly, the influences of foreign ions on Cr(VI) reduction were investigated to mimic real sewage, which revealed that no obvious adverse effects can be found with the presence of common foreign ions in sewage. The photocatalytic membrane material developed in this study provides a new idea for treating Cr(VI)-containing wastewater and has a more significant application prospect.
虽然传统粉末光催化剂将Cr(VI)光催化还原为Cr(III)是一种很有前景的方法，但从水中回收光催化剂存在困难且回收率低，这阻碍了它们的广泛实际应用。在此，我们展示了通过借助聚乙烯醇（PVA）进行化学接枝，将FeCO/BiWO（FeCO/BWO）复合材料紧密结合到改性聚偏氟乙烯（PVDF）膜上，以形成光催化复合膜（PVDF@PVA-FeCO/BWO）。PVDF@PVA-FeCO/BWO（FeCO/BWO含量为0.06 wt%）的接触角为48.0°，远低于纯PVDF膜的接触角（80.5°）。同时，观察到PVDF@PVA-FeCO/BWO复合膜的渗透通量为61.43 g m⁻² h⁻¹，水通量为250.60 L m⁻² h⁻¹。复合膜的拉伸强度达到48.84 MPa，是PVDF膜的9.8倍。结果发现，PVDF@PVA-FeCO/BWO膜在模拟阳光和实际阳光照射下均表现出优异的光催化还原Cr(VI)性能。在黑暗过程中，PVDF@PVA-FeCO/BWO对Cr(VI)的吸附在30分钟内可达47.6%，光照10分钟后，Cr(VI)的去除率可达100%，速率常数为0.2651 min⁻¹，表明复合膜对Cr(VI)的去除具有吸附和光还原的协同作用。PVDF@PVA-FeCO/BWO膜在连续七个循环后具有良好的稳定性和可重复使用性。最重要的是，研究了外来离子对Cr(VI)还原的影响以模拟实际污水，结果表明污水中常见外来离子的存在不会产生明显的不利影响。本研究开发的光催化膜材料为处理含Cr(VI)废水提供了新思路，具有更显著的应用前景。
