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Generation and Control of Electrohydrodynamic Flows in Aqueous Electrolyte Solutions
Published on: September 7, 2018
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Effective fluoride removal from brackish groundwaters by flow-electrode capacitive deionization (FCDI) under a
Huan Jiang1, Jing Zhang1, Kunyue Luo1
1College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China.
The Science of the Total Environment
|September 13, 2021
Summary
Flow-electrode capacitive deionization (FCDI) effectively treats brackish groundwater contaminated with fluoride. The short-circuited closed-cycle (SCC) mode proved most advantageous for fluoride and chloride removal.
Area of Science:
- Environmental Science
- Water Treatment Technologies
- Electrochemistry
Background:
- Fluoride contamination in brackish groundwater poses significant health risks.
- Conventional water treatment methods can be energy-intensive or inefficient for fluoride removal.
- Flow-electrode capacitive deionization (FCDI) offers a promising alternative for water desalination and contaminant removal.
Purpose of the Study:
- To evaluate the effectiveness of FCDI for treating fluoride-contaminated brackish groundwater.
- To compare different operational modes of FCDI, including short-circuited closed-cycle (SCC), isolated closed-cycle (ICC), and single cycle (SC).
- To investigate the impact of key operational parameters on fluoride and chloride removal.
Main Methods:
- FCDI system was employed to treat synthetic brackish groundwater spiked with fluoride.
- Three operational modes (SCC, ICC, SC) were compared to determine the most effective configuration.
- Parameters such as current density, hydraulic residence time (HRT), activated carbon (AC) loading, and feed concentration were systematically varied in SCC mode.
- Effluent concentrations of fluoride (F-) and chloride (Cl-) were monitored to assess removal efficiency and selectivity.
Main Results:
- The SCC mode demonstrated superior performance for fluoride and chloride removal compared to ICC and SC modes.
- Steady-state effluent chloride concentration decreased with increasing current density, HRT, and AC loading.
- Fluoride removal reached a stable minimum under low applied current, with HRT and AC loading showing minimal impact.
- FCDI exhibited preferential removal of fluoride over chloride, with higher selectivity achieved at lower current densities and shorter HRTs.
- Removal efficiencies for both ions decreased with increasing feed NaCl concentration.
Conclusions:
- FCDI, particularly in SCC mode, is a viable and effective technology for the treatment of fluoride-contaminated brackish groundwater.
- Operational parameters can be optimized to enhance ion selectivity and removal efficiency.
- Further research and development can establish FCDI as a practical solution for addressing fluoride contamination in drinking water sources.
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