Precipitation Removal of Fluoride from Semiconductor Wastewater

Chang, Meng-Chun; Liu, J. C.

doi:10.1061/(asce)0733-9372(2007)133:4(419)

Cited by 101 publications

(36 citation statements)

References 21 publications

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“…Numerous research efforts are being made to develop methods to remove various types of anions. Most treatment methods to remove anions from waters include chemical precipitation [1], simple and chelating ion exchange [2,3], sorption [4,5], membrane systems [6], etc. The sorption of anions by some naturally occurring biopolymers [7] and synthetic polymers [8] has recently gained much attention.…”

Section: Introductionmentioning

confidence: 99%

Quaternized poly(1-vinylimidazole) hydrogel for anion adsorption

2015

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Poly(1-vinylimidazole) (PVIm) hydrogels were synthesized through free radical polymerization/crosslinking of 1-vinylimidazole (VIm) in aqueous solutions with azobisisobutyronitrile (AIBN) used as the initiator and N,N 0 -methylenebisacrylamide (MBAAm) as the crosslinking agent. To quaternize PVIm, dimethylsulfate was used as the methylating agent. Pristine and quaternized PVIm hydrogels were characterized by spectroscopic techniques. Finally, ground hydrogels were used in anion adsorption. The amount of anion adsorbed (in m-eq. anion/g polymer) and adsorption% was determined for fluoride, bromide, nitrite, nitrate, phosphate and sulfate anions using ion chromatography techniques. The amount of phosphate adsorbed on QPVIm hydrogel was the highest and the amount of fluoride adsorbed on QPVIm hydrogel was the lowest. Ion chromatographic study showed that when 1/1 mol ratio of anion to polymer (on a repeating unit basis) was used, 24.7 % of fluoride, 60.6 % of nitrite, 61.6 % of bromide, 63.0 % of nitrate, 99.3 % of phosphate and 98.2 % of sulfate were removed from the medium.

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Section: Introductionmentioning

confidence: 99%

Quaternized poly(1-vinylimidazole) hydrogel for anion adsorption

2015

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“…Many technologies to remove fluoride from groundwater and industrial wastewater such as (electro)coagulation, adsorption, ion exchange, precipitation, and membrane separation have been well studied [1][2][3][4][5][6]. Coagulation and adsorption are highly efficient and cost-effective, and require less maintenance and show higher water production ratios than other processes.…”

Section: Introductionmentioning

confidence: 99%

Defluoridation by Al-based coagulation and adsorption: Species transformation of aluminum and fluoride

Liu

et al. 2015

Separation and Purification Technology

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a b s t r a c tThe species transformation of Al and fluoride in fluoride removal by Al-based coagulation and adsorption is far from being well-characterized. This study used batch-and pilot-scale experiments to compare the fluoride removal efficiency and species transformation of Al and fluoride in Al coagulation with that in Al precipitate (AlOxHy) adsorption. Al coagulation showed superior removal of fluoride compared to AlOxHy adsorption. In the coagulation process, the formation of complexed fluoride (Com-F) occurred, and Com-F concentrations increased with elevated Al dose, i.e., lowered pH. At initial pH of 8.6, free fluoride (Free-F) dominated in the adsorption system even at the high AlOxHy dose of 200 mg Al/L whereas at pH < 7.0, Com-F was the dominant species in both systems. Fluoride had an influence on Al 3+ hydrolysis and favored the transformation of Al 3+ and Al-F complexes to Al-F precipitates, and the removal of fluoride by coagulation was improved thereafter. Fluoride also promoted the dissolution of AlOxHy, the extent of which was more significant at lowered pH from 7.0 to 4.0 and at elevated ratios of fluoride to Al from 0.15 to 2.45. The formation of Al-F complexes impaired fluoride removal by adsorption. A pilot-scale field study also indicated that coagulation showed higher efficiency than adsorption in the removal of fluoride. The average ratios of Com-F to total fluoride were 0.14:1 and 0.04:1, respectively, in coagulation and adsorption processes.

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“…E-mail address: liu1958@mail.ntust.edu.tw (J.C. Liu). calcium chloride (CaCl 2 ) and lime to induce CaF 2 precipitates [7,8]. The reaction is shown as:…”

Section: Introductionmentioning

confidence: 99%

Coupled precipitation-ultrafiltration for treatment of high fluoride-content wastewater

Liu

2016

Journal of the Taiwan Institute of Chemical Engineers

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Precipitation Removal of Fluoride from Semiconductor Wastewater

Cited by 101 publications

References 21 publications

Quaternized poly(1-vinylimidazole) hydrogel for anion adsorption

Quaternized poly(1-vinylimidazole) hydrogel for anion adsorption

Defluoridation by Al-based coagulation and adsorption: Species transformation of aluminum and fluoride

Coupled precipitation-ultrafiltration for treatment of high fluoride-content wastewater

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