Efficient Removal of Fluoride by Complexation Extraction: Mechanism and Thermodynamics

Abstract

A complexation extraction system was designed to develop a new process for the efficient removal of fluoride from solutions, such as zinc or copper electrolytes or wastewater derived from flue gas. The effects of the boron fluoride molar ratio, organic phase composition, initial pH, temperature, and phase volume ratio on the extraction efficiency were investigated. The extraction efficiency was found to increase with the increase in the boron fluoride molar ratio, Alamine336 concentration, and phase volume ratio, whereas it decreased with the increase in temperature. For the simulated electrolyte or wastewater derived from flue gas, the majority of metallic ions were insensitive to the extraction, with the exception of Al3+ and Fe3+. Fluoride decreased from 5 g/L to 0.05 g/L after two-stage cross-flow extraction alone; with an extraction efficiency of 99%. Both the stripping and cycling properties were excellent when sodium hydroxide was employed as the stripping reagent. Furthermore, the loading capacity was 43.4 g/L, and increased by four times, when boric acid was added. This novel process implies a wide range of potential applications, such as the removal of unwanted fluoride ions from various high-fluoride polluted solutions and the simplification of brine phase diagram.

Research of advanced treatment technologies for chlorophenol wastewater

“…Extraction is a typical production process in chemicals, materials, wet metallurgy, and other industrial production. In recent years, extraction is also primarily used in the field of environmental pollutant removal, making full use of the different partition coefficients of the target pollutant in the extractant and water so that the target pollutant is transferred from the polluted water and diffused into the extractant to achieve the purpose of removing the target pollutant [6] . A good extractant is a key to improving extraction efficiency, and several types of organic extractants are commonly used, such as alcohols, hydrocarbons, ethers, and ketones [7,8] .…”

Thermodynamic Analysis and Experimental Optimization for the Purification of Ni-Co-Mn Mixed Sulfate Solution from the Recovery Process of Lithium-Ion Batteries

“…The pH of the leaching solution can be adjusted to between 5 and 7, and then insoluble alkali metal oxides or rare earth carbonate (La, Ce, etc.) can be added to achieve the purpose of deep removal of F [22,23]. Since both AlPO 4 and FePO 4 are in the form of precipitates, Al, Fe, and P can be removed at the same time by controlling the pH of the leach solution.…”

Enhancing the adsorption function of F- by iron and zirconium doped zeolite: Characterization and parameter optimization

“…As a semi-essential trace element for human beings, fluorine at low levels (< 1.5 mg/L) is beneficial to human health [1][2][3]. However, with the rapid development of industry and agriculture, a large amount of high concentration fluorine-containing wastewaters that come from electroplating, metal processing and other industries, as well as phosphate fertilizers manufacturing were produced [4,5].…”