Effective As(III) Removal by A Multi-Charged Hydroacid Complex Draw Solute Facilitated Forward Osmosis-Membrane Distillation (FO-MD) Processes

Qingchun Ge, Gang Han, Neal Tai-Shung Chung

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50 Scopus citations


© 2016 American Chemical Society. Effective removal of As(III) from water by an oxalic acid complex with the formula of Na3[Cr(C2O4)3] (Na-Cr-OA) is demonstrated via an forward osmosis-membrane distillation (FO-MD) hybrid system in this study. Na-Cr-OA first proved its superiority as a draw solute with high water fluxes and negligible reverse fluxes in FO, then a systematic investigation of the Na-Cr-OA promoted FO process was conducted to ascertain the factors in As(III) removal. Relatively high water fluxes of 28 LMH under the FO mode and 74 LMH under the pressure retarded osmosis (PRO) mode were achieved when using a 1000 ppm As(III) solution as the feed and 1.0 M Na-Cr-OA as the draw solution at 60 °C. As(III) removal with a water recovery up to 21.6% (FO mode) and 48.3% (PRO mode) were also achieved in 2 h. An outstanding As(III) rejection with 30-3000 μg/L As(III) in the permeate was accomplished when As(III) feed solutions varied from 5 × 104 to 1 × 106 μg/L, superior to the best FO performance reported for As(III) removal. Incorporating MD into FO not only makes As(III) removal sustainable by reconcentrating the Na-Cr-OA solution simultaneously, but also reduces the As(III) concentration below 10 μg/L in the product water, meeting the WHO standard.
Original languageEnglish (US)
Pages (from-to)2363-2370
Number of pages8
JournalEnvironmental Science & Technology
Issue number5
StatePublished - Feb 10 2016

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This research is supported by both the National Research Foundation- Prime Minister's office, Republic of Singapore under its Competitive Research Program entitled "Advanced FO Membranes and Membrane Systems for Wastewater Treatment, Water Reuse and Seawater Desalination" (Grant numbers: R-279-000-336-281 and R-279-000-339-281), and Fuzhou University (Grant numbers: 510160 and 521142). Special thanks are given to Ms. Jie Gao, Mr. Zhenlei Cheng, and Mr. Zhiwei Thong for their valuable help.


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