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Novel Multicharge Hydroacid Complexes That Effectively Remove Heavy Metal Ions from Water in Forward Osmosis
Qiaozhen Chen1, Wenxuan Xu1, Qingchun Ge1
1College of Environment and Resources , Fuzhou University , Fujian 350116 , China.
Abstract:
Suitable draw solutes are crucial to maximize the potential of forward osmosis (FO) in water treatment. In this study, a novel three-dimensional, multicharge draw solute of oxalic acid (OA) chromium complex in a tetramethylammonium salt of [N(CH3)4]3[Cr(C2O4)3] (NMe4-Cr-OA) was developed for electroplating wastewater treatment using FO processes. The newly designed NMe4-Cr-OA has a Cr-centered octahedral structure and can ionize a multicharge anion [Cr(C2O4)3]3- and three cations [N(CH3)4]- in its aqueous solution. Such characteristics are conducive to not only generating a high osmotic pressure but also minimizing reverse solute flux in an FO process, thus resulting in good FO performance. A high water recovery with a negligible reverse solute flux was achieved for NMe4-Cr-OA in electroplating wastewater treatment via the FO process. Furthermore, a significant increase of 77% in FO efficiency was obtained when NMe4-Cr-OA replaced the conventional draw solute of NH4HCO3 for FO electroplating wastewater treatment with a copper rejection higher than 99.9%, which surpasses the best performance of other technologies reported for copper ion removal.
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