Controllable and selective fluoride precipitation from phosphate-rich wastewater
Shuyue Feng1, Wenjuan Zhang2, Jianyong Che1
1State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China.
The Science of the Total Environment
|August 15, 2024
Summary
Lanthanum hydroxide effectively removes fluoride from industrial wastewater, separating it from phosphate. This method achieves high fluoride removal efficiency under specific acidic conditions, aiding resource recovery.
Area of Science:
- Environmental Chemistry
- Materials Science
- Chemical Engineering
Background:
- Industrial wastewater often contains high concentrations of fluoride and phosphate, presenting environmental concerns and resource wastage.
- Effective separation of fluoride and phosphate is crucial for wastewater treatment and potential resource recovery.
Purpose of the Study:
- To investigate the use of lanthanum hydroxide (La(OH)3) as a precipitating agent for selective fluoride removal from wastewater.
- To optimize conditions for fluoride precipitation and separation from phosphate.
- To understand the mechanism of selective fluoride precipitation.
Main Methods:
- Experimental investigation of fluoride and phosphate removal using La(OH)3 under varying pH and dosage.
- Optimization of precipitation conditions using Response Surface Methodology (RSM).
- Characterization and Density Functional Theory (DFT) calculations to confirm the mechanism of selective precipitation.
Main Results:
- Optimal conditions for fluoride removal were identified: pH 1.0-2.5, 60-80 min reaction time, La/3F molar ratio of 2.0, and 25 °C.
- Fluoride removal efficiency exceeded 96.9% under optimal conditions, with minimal phosphate removal (around 7.2%).
- DFT calculations and characterization confirmed La(OH)3 selectively precipitates as lanthanum fluoride (LaF3) in acidic conditions, not lanthanum phosphate (LaPO4).
Conclusions:
- La(OH)3 is an effective precipitating agent for the selective removal and separation of fluoride from phosphate in industrial wastewater.
- The study demonstrates a viable strategy for treating fluoride and phosphate-rich wastewater, enabling selective precipitation and recovery.
- This approach contributes to sustainable wastewater management and resource recovery.
Keywords:
Chemical precipitationFluoride removalResponse surface methodologySeparation of fluoride and phosphateWastewater treatmentMore Related Videos
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