College of Environment and Resources , Fuzhou University , Fujian 350116 , China.
School of Engineering , The University of Edinburgh , Robert Stevenson Road, The King's Buildings , Edinburgh , EH9 3FB , Scotland, U.K.
Environ Sci Technol. 2018 Mar 20;52(6):3812-3819. doi: 10.1021/acs.est.7b06506. Epub 2018 Mar 9.
The potential of forward osmosis for water treatment can only be maximized with suitable draw solutes. Here a three-dimensional, multicharge draw solute of decasodium phytate (Na-phytate) is designed and synthesized for removing organic arsenicals from water using a hybrid forward osmosis (FO) - membrane distillation (MD) process. Efficient water recovery is achieved using Na-phytate as a draw solute with a water flux of 20.0 LMH and negligible reverse solute diffusion when 1000 ppm organic arsenicals as the feed and operated under ambient conditions with FO mode. At 50 °C, the novel draw solute increases water flux by more than 30% with water fluxes higher than 26.0 LMH on the FO side, drastically enhancing water recovery efficiency. By combining the FO and MD processes into a single hybrid process, a 100% recovery of Na-phytate draw solute was achieved. Crucially, organic arsenicals or Na-phytate draw solutes are both rejected 100% and not detected in the permeate of the hybrid process. The complete rejection of both organic arsenicals and draw solutes using hybrid membrane processes is unprecedented; creating a new application for membrane separations.
只有使用合适的汲取剂，正向渗透才能最大程度地用于水处理。在这里，设计并合成了一种三维、多电荷的汲取剂——植酸钠（Na-phytate），用于使用混合正向渗透（FO）-膜蒸馏（MD）工艺从水中去除有机砷。当以 FO 模式在环境条件下运行时，使用 Na-phytate 作为汲取剂，进水为 1000ppm 有机砷，水通量为 20.0LMH，反向溶质扩散可忽略不计，可实现高效的水回收。在 50°C 下，新型汲取剂使水通量增加了 30%以上，FO 侧的水通量高于 26.0LMH，大大提高了水回收效率。通过将 FO 和 MD 工艺结合到单个混合工艺中，实现了 Na-phytate 汲取剂 100%的回收。至关重要的是，有机砷或 Na-phytate 汲取剂在混合膜工艺的渗透物中都被 100%截留，且无法检出。使用混合膜工艺完全截留有机砷和汲取剂是前所未有的，为膜分离创造了新的应用。
