Precipitation flotation of phosphate from water

Liu, J.C.; Warmadewanthi,; Chang, Ching-Jung

doi:10.1016/j.colsurfa.2009.04.036

Cited by 28 publications

(11 citation statements)

References 14 publications

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“…Although studies showed that calcium phosphate minerals could be utilized as fertilizers as well, these turned out not to be as efficient as pure struvite [64], as their P-available content in soils was lower than the latter but was still acceptable [65]. Calcium phosphate compounds are also difficult to settle [60,66]. ACP, in time, will be transformed to more stable forms, such as hydroxyapatite (HAP).…”

Section: Use Of Final Precipitates As Fertilizersmentioning

confidence: 99%

Impact of pH and Ionic Molar Ratios on Phosphorous Forms Precipitation and Recovery from Different Wastewater Sludges

et al. 2018

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Phosphorus is an essential nutrient for plants, which use it as a basic fertilizer component and is expected to increase significantly in the coming years due to higher food crops demand. Unfortunately, the available phosphorus natural reserves are not renewable, and estimates indicate their rapid decline in the future. Urban wastewater, due to its abundance and relatively high phosphorus content, is an excellent candidate for phosphorus recovery, while the element's removal from urban effluents was introduced in the 1970 s to limit the undesired effects of eutrophication. In this study, the process of struvite (and related phosphorous compounds) crystallization was investigated for three different sludge types, and the results were compared. While most studies focus strictly on anaerobically digested sludge for high struvite precipitation efficiency, this study investigated the possibility of inducing precipitation on both aerobic (extended aeration) and anaerobic sludges produced by two wastewater treatment plants in northern Italy. Analysis of precipitates from sludge samples was compared, where the focus was on the aerobic sludge, and its potential for struvite recovery. The effect of different reaction parameters was studied under different operating conditions, and the use and effects of Ca(OH) 2 addition as an inexpensive potential pH adjustment reagent was investigated.

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Section: Use Of Final Precipitates As Fertilizersmentioning

confidence: 99%

Impact of pH and Ionic Molar Ratios on Phosphorous Forms Precipitation and Recovery from Different Wastewater Sludges

et al. 2018

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“…It can be observed that the precipitate is composed of a mixture of hydroxyapatite [hydroxide calcium phosphate, Ca5(PO4)3(OH)] and a calcium-deficient hydroxyapatite [hydroxide calcium hydrogen phosphate Ca9HPO4(PO4)5OH] which is a non-stoichiometric hydroxyapatite. According to some authors (Abbona et al, 1986;Musvoto et al, 2000;Liu et al, 2009), hydroxyapatite precipitation starts at pH> 5; however, the precipitation reaction kinetics is not favored and other species, such as amorphous calcium phosphate, octacalcium phosphate and brushite, act as precursors of the hydroxyapatite precipitation. Gray and Schwab (1993) reported that calcium phosphate precipitation is almost complete at pH values higher than 9.8.…”

Section: Precipitate Characterizationmentioning

confidence: 99%

“…Aluminum and iron salts present the disadvantage of generating sludge, which cannot be reused or reclaimed (Urano and Tachikawa,exploited in phosphate rock mining for fertilizer production and present the potential for reuse and recycling. However, calcium phosphate precipitates are difficult to settle, requiring the use of flocculants (Liu and Chang, 2009). Thus, there is a need to employ other solid/liquid separation techniques, such as flotation, which is a well established technique for minerals separation and is also commercially used for wastewater treatment (Hoseinian et al, 2015;Matis, 1995;Rubio et al, 1996;Rubio, 1998a,b;Rubio et al, 2002;Voronin and Dibrov, 1999).…”

Section: Introductionmentioning

confidence: 99%

Electroflotation of precipitated phosphate from synthetic solution

Cruz

Monte

Dutra

2017

Braz. J. Chem. Eng.

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-The phosphate recovery from a 20 mg L -1 Na2HPO4 solution through precipitation with Ca(OH)2 followed by electroflotation was evaluated. X-ray diffraction and particle size measurements indicated that the precipitates were a mixture of hydroxyapatite and calcium-deficient hydroxyapatite, with size ranging from 3 to 10 mm. Electroflotation with Na-oleate as surfactant was used to recover the precipitates. The surfactant adsorption was evaluated through zeta potential measurements. The influence of Na-oleate concentration, pH and bubble size on phosphate recovery was investigated. In the absence of Na-oleate, a phosphate recovery of 50% was achieved, while in the presence of 20 mg L -1 of Na-oleate it was increased to 90%, at pH 11. The phosphate recovery also increased with Ca(OH)2 concentration increase and bubble size decrease, reaching 100% at 300 mg L -1 Ca(OH)2 and bubble size around 39 µm.

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“…10 Among iron-based nanoparticles, zerovalent iron (nZVI) exhibited signicantly higher adsorptive removal capacity towards phosphate than other adsorbents, which is caused by the synergetic effect of precipitation and chemical adsorption during the removal of phosphate. 11 However, nZVI has certain shortcomings, including ease of aggregation and oxidation, which adversely affect its adsorptive removal performance. 12 To alleviate these detrimental effects, stabilization of nZVI on carriers that are compatible with the adsorptive removal process, i.e., activated carbon and activated carbon ber, have been proposed as an effective strategy that not only reduces nZVI agglomeration, but also prevents its oxidation.…”

Section: Introductionmentioning

confidence: 99%