Hydrofluoric acid and sodium hydroxide production by bipolar membrane electrodialysis

Erkmen, Jülide; Yapıcı, Sinan; Arzutuğ, M. Emin; Aydın, Özkan; Ata, Osman Nuri; Öner, Muhammed Raşit

doi:10.1080/19443994.2015.1107753

Cited by 10 publications

(2 citation statements)

References 14 publications

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“…Bipolar membrane electrodialysis (BMED) can be used to generate H + and OH – through the dissociation of water molecules in a bipolar membrane (BM). Then, the cation/anion will migrate through cation/anion-exchange membranes (CEMs/AEMs) to form a base/acid, respectively, under an electric field. − Therefore, BMED could be designed to produce acid and base for the continuous generation of HF in fluoride-rich wastewater …”

Section: Introductionmentioning

confidence: 99%

“…24−26 Therefore, BMED could be designed to produce acid and base for the continuous generation of HF in fluoride-rich wastewater. 27 In this study, a closed-loop process based on resource capture ultrafiltration−bipolar membrane electrodialysis (RCUF-BMED) was designed to recover fluoride and silica as Na 2 SiF 6 from fluoride-rich and silica-rich wastewaters, and the feasibility of the RCUF-BMED system was demonstrated. Two key parts are essential for the RCUF-BMED system: (1) capture of the fluoride and silica to generate Na 2 SiF 6 in an acid environment, and recovery of the Na 2 SiF 6 using a base by the UF system and (2) acid/base generation and freshwater recovery by the BMED system.…”

Section: Introductionmentioning

confidence: 99%

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Recovery of Fluoride-Rich and Silica-Rich Wastewaters as Valuable Resources: A Resource Capture Ultrafiltration–Bipolar Membrane Electrodialysis-Based Closed-Loop Process

Qiu

Ren

Xia

et al. 2022

Environ. Sci. Technol.

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Traditional technologies such as precipitation and coagulation have been adopted for fluoride-rich and silica-rich wastewater treatment, respectively, but waste solid generation and low wastewater processing efficiency are still the looming concern. Efficient resource recovery technologies for different wastewater treatments are scarce for environment and industry sustainability. Herein, a resource capture ultrafiltration–bipolar membrane electrodialysis (RCUF-BMED) system was designed into a closed-loop process for simultaneous capture and recovery of fluoride and silica as sodium silicofluoride (Na2SiF6) from mixed fluoride-rich and silica-rich wastewaters, as well as achieving zero liquid discharge. This RCUF-BMED system comprised two key parts: (1) capture of fluoride and silica from two wastewaters using acid, and recovery of the Na2SiF6 using base by UF and (2) UF permeate conversion for acid/base and freshwater generation by BMED. With the optimized RCUF-BMED system, fluoride and silica can be selectively captured from wastewater with removal efficiencies higher than 99%. The Na2SiF6 recovery was around 72% with a high purity of 99.1%. The aging and cyclic experiments demonstrated the high stability and recyclability of the RCUF-BMED system. This RCUF-BMED system has successfully achieved the conversion of toxic fluoride and silica into valuable Na2SiF6 from mixed wastewaters, which shows great application potential in the industry–resource–environment nexus.

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