Phosphorus release and recovery by reductive dissolution of chemically precipitated phosphorus from simulated wastewater

被引：2

作者：

Alnimer A.A. ^{[1
]}

Smith D.S. ^{[1
]}

Parker W.J. ^{[2
]}

机构：

[1] Department of Chemistry and Biochemistry, Wilfrid Laurier University, 75 University Ave. W., Waterloo, N2L 3C5, ON

[2] Department of Civil and Environmental Engineering, University of Waterloo, 200 University Ave. W., Waterloo, N2L 3G1, ON

来源：

Chemosphere | 2023年 / 345卷

基金：

加拿大自然科学与工程研究理事会;

关键词：

Ascorbic acid; Chelating agent; Chemically mediated phosphorus removal; Geochemical modeling; Phosphorus; Phosphorus recovery; Reductive dissolution; Vivianite; Wastewater;

D O I：

10.1016/j.chemosphere.2023.140500

中图分类号：

学科分类号：

摘要：

Chemically mediated recovery of phosphorous (P) as vivianite from the sludges generated by chemical phosphorus removal (CPR) is a potential means of enhancing sustainability of wastewater treatment. This study marks an initial attempt to explore direct P release and recovery from lab synthetic Fe–P sludge via reductive dissolution using ascorbic acid (AA) under acidic conditions. The effects of AA/Fe molar ratio, age of Fe–P sludge and pH were examined to find the optimum conditions for Fe–P reductive solubilization and vivianite precipitation. The performance of the reductive, chelating, and acidic effects of AA toward Fe–P sludge were evaluated by comparison with hydroxylamine (reducing agent), oxalic acid (chelating agent), and inorganic acids (pH effect) including HNO3, HCl, and H2SO4. Full solubilization of Fe–P sludge and reduction of Fe3+ were observed at pH values 3 and 4 for two Fe/AA molar ratios of 1:2 and 1:4. Sludge age (up to 11 days) did not affect the reductive solubilization of Fe–P with AA addition. The reductive dissolution of Fe–P sludge with hydroxylamine was negligible, while both P (95 ± 2%) and Fe3+ (90 ± 1%) were solubilized through non-reductive dissolution by oxalic acid treatment at an Fe/oxalic acid molar ratio 1:2 and a pH 3. With sludge treatment with inorganic acids at pH 3, P and Fe release was very low (<10%) compared to AA and oxalic acid treatment. After full solubilization of Fe–P sludge by AA treatment at pH 3 it was possible to recover the phosphorus and iron as vivianite by simple pH adjustment to pH 7; P and Fe recoveries of 88 ± 2% and 90 ± 1% respectively were achieved in this manner. XRD analysis, Fe/P molar ratio measurements, and magnetic attraction confirmed vivianite formation. PHREEQC modeling showed a reasonable agreement with the measured release of P and Fe from Fe–P sludge and vivianite formation. © 2023

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