Spontaneous precipitation of struvite from aqueous solutions

Bouropoulos, Nikolaos; Koutsoukos, Petros G.

doi:10.1016/s0022-0248(00)00351-1

Cited by 289 publications

(189 citation statements)

References 14 publications

Supporting

Mentioning

175

Contrasting

Unclassified

Order By: Relevance

“…At the equilibrium pH 9 and in the presence of Ca ions, the element Mg 2+ , NH 4+ , and PO4 3-may form ion complexes, such as MgOH+, MgCl, Mg(NH3)2 + 2, MgPO4-, MgHPO4+, NH4 1-, Mg(NH3)2 +2 , NH3, CaNH3 +2 , Ca(NH3)2 +2 , Ca(NH3)2 +2 , HPO4 -2 , H2PO4-, MgPO4-, MgHPO4, CaHPO4, CaPO4-, CaH2PO4+, KHPO4-, K2HPO4 in the system. These ion complexes agree with the finding results of previous works (Bouropoulos and Koutsoukos, 2000;Ohlinger et al, 2000).…”

Section: Discussion Chemical Equilibrium Model and Mineral Speciatiosupporting

confidence: 93%

“…These elemental analyses further confirm that the deposits formed into this condition are gypsum, CaCl2 and Struvite, in agreement with XRPD . In some of literature, the formation of struvite crystals can be found in the pH range of 7-11 (Bouropoulos and Koutsoukos, 2000;Ohlinger et al, 2000). In this range pH, a few crystals may form as trimagnesium phosphate (Musvoto et al, 2000).…”

Section: Discussion Chemical Equilibrium Model and Mineral Speciatiomentioning

confidence: 98%

“…It must be yet pointed out that other precipitates may occur for pH values above 9 (Bouropoulos and Koutsoukos, 2000;Ohlinger et al, 2000).…”

Section: Discussion Chemical Equilibrium Model and Mineral Speciatiomentioning

confidence: 99%

See 2 more Smart Citations

Effect of Calcium Additive on the Crystallization of Struvite

Perwitasari

Edahwati

Sutiyono

et al. 2016

MATEC Web of Conferences

View full text Add to dashboard Cite

Crystallization of struvite [MgNH4PO4.6H2O] may lead to the deposition of scale which may create significant problems in the process pipes, pumps and other industrial equipment. However, struvite precipitation can be benefited for phosphate recovery for use of fertilizer. The aim at the present work was to investigate calcium additive on struvite precipitation. The experiment was carried out in a batch mode using a 1-liter Pyrex glass vessel mechanically agitated for 200 rpm. The scale-forming solution was prepared for mixing solutions to MgCl2 and NH4H2PO4 with Mg +2 , NH4 + and PO4 -3 in a molar ratio of 1: 1:1. The crystallization temperature of 30 and 40 O C was selected. Ca was added into the crystallizing solution to chloride dihydrate 0.4M (CaCl2•2H2O). Then each solution was pH adjusted to 9 by addition of KOH. The crystals obtained were characterized using SEM for morphology, EDS for elemental analysis as well as XRPD Rietveld analysis for crystaline phases. The induction periods varied from 10 to 90 min, which means that the struvite crystals began forming 10 to 90 min after mixing of the solution. It was observed that the Ca additive may inhibit the struvite crystallization. SEM analysis revealed that the struvite crystals obtained were predominantly of irregular prismatic morphology. Furthermore, the EDS pattern revealed that the elemental composition of the crystals consisted of Ca, Cl, S Mg, N, and P, providing that many crystalline phase found in the crystals such as Gypsum, CaCl2, struvite, struvite-(K) and sylvite. It was observed that the Ca additive appeared to inhibit the struvite crystallization.

show abstract

Section: Discussion Chemical Equilibrium Model and Mineral Speciatiosupporting

confidence: 93%

Section: Discussion Chemical Equilibrium Model and Mineral Speciatiomentioning

confidence: 98%

See 1 more Smart Citation

Effect of Calcium Additive on the Crystallization of Struvite

Perwitasari

Edahwati

Sutiyono

et al. 2016

MATEC Web of Conferences

View full text Add to dashboard Cite

show abstract

“…The influence of pH and supersaturation on the precipitation rate and crystal characteristics of struvite has been demonstrated by a number of authors [12][13][14][15][16], but as yet little interest has been paid to the influence of foreign ions on struvite nucleation and crystallisation.…”

Section: Introductionmentioning

confidence: 99%

Impact of calcium on struvite crystal size, shape and purity

Corre

Valsami-Jones

Hobbs³

et al. 2005

Journal of Crystal Growth

357

217

View full text Add to dashboard Cite

Struvite precipitation occurs spontaneously in wastewater treatment plants under conditions that are influenced by many factors including concentration of PO ions, pH, temperature and mixing energy. These parameters are often difficult to control and as a result struvite generates problems of scale deposits in areas such as pipes and recirculation pumps. At the same time, struvite is considered as a potentially marketable product as an alternative fertiliser. For those two reasons, it has become important to study the principles of struvite precipitation, and to assess the parameters controlling struvite crystallisation. In the present work the influence of 2 effects of Ca 2+ ions on size, shape, and purity of the crystals formed. Tools used include particle size analysis, X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDS). The experimental results showed that the presence of calcium in the media can affect significantly struvite crystal growth, and the characteristics of the crystal produced.

show abstract

“…With a pH increase, struvite solubility decreases with a minimal K sp value corresponds to pH 10.3 (Ohlinger et al, 1998) or 10.7 (Snoeyink and Jenkins, 1980); thus its precipitation potential grows (Parsons, 2001). Also the induction time necessary for initiation of the batch nucleation process of stru-vite shortens (Bouropoulos and Koutsoukos, 2000;Kofina and Koutsoukos, 2005;Le Corre et al 2007b).…”

Section: Introductionmentioning

confidence: 99%

Effect of Continuous Crystallizer Performance on Struvite Crystals Produced in Reaction Crystallization From Solutions Containing Phosphate(v) and Zinc(ii) Ions

Hutnik

Wierzbowska

Piotrowski

et al. 2016

Braz. J. Chem. Eng.

View full text Add to dashboard Cite

-Continuous reaction crystallization of struvite from aqueous solutions containing phosphate(V) (1.0 mass %) and zinc(II) ions (from 0.1 to 2.0 mg kg -1 ) in a continuous DT MSMPR crystallizer was investigated. The influence of pH (9 -11) and mean residence time (900 -3600 s) on the product characteristics and its chemical composition was tested. Struvite crystals of mean size 22-41 m were produced. An increase in Zn 2+ concentration decreased the mean crystal size and homogeneity. An elevation of the pH also decreased the struvite crystal size. Augmenting the mean residence time influenced product quality advantageously. Coexistence of struvite and Zn(OH) 2 in the product was confirmed analytically.

show abstract

Spontaneous precipitation of struvite from aqueous solutions

Cited by 289 publications

References 14 publications

Effect of Calcium Additive on the Crystallization of Struvite

Effect of Calcium Additive on the Crystallization of Struvite

Impact of calcium on struvite crystal size, shape and purity

Effect of Continuous Crystallizer Performance on Struvite Crystals Produced in Reaction Crystallization From Solutions Containing Phosphate(v) and Zinc(ii) Ions

Contact Info

Product

Resources

About