Nucleação na formação de estruvita: estado da arte

Morita, Dione Mari; Avila, Renan de Luca; Aidar, Fernando Ngan

doi:10.1590/S1413-41522019113711

Dione Mari Morita ^**Autor correspondente: dmmorita@usp.br

Universidade de São Paulo - São Paulo (SP), Brasil.

http://orcid.org/0000-0002-0506-0972

Renan de Luca Avila

Universidade de São Paulo - São Paulo (SP), Brasil.

http://orcid.org/0000-0002-9284-8310

Fernando Ngan Aidar

Universidade de São Paulo - São Paulo (SP), Brasil.

http://orcid.org/0000-0002-2044-9839

*Autor correspondente: dmmorita@usp.br

Thumbnail

Figura 1 -
Variação das concentrações das espécies de fósforo em função do pH: (A) em diferentes temperaturas; (B) em diferentes intensidades iônicas; (C) em diferentes concentrações totais de fósforo.

Thumbnail

Figura 2 -
Tempo de indução em função da razão de supersaturação obtidos por diferentes autores.

Thumbnail

Tabela 1 -
Influência do cálcio na formação da estruvita.

Thumbnail

Tabela 2 -
Reações consideradas pelos pesquisadores que estudaram os aspectos termodinâmicos da formação e dissolução da estruvita.

Thumbnail

Tabela 3 -
Valores da constante do produto de solubilidade de atividade (pK_S0) da estruvita obtidos por diferentes pesquisadores.

Thumbnail

M g 3 H P O 4 . 3 H 2 O ↔ 3 H 2 O + H P O 4 2 - + M g 2 + -5,8 (KPS) Musvoto et al. (2000), Çelen et al. (2007)

Thumbnail

M g H P O 4 . 3 H 2 O ↔ 3 H 2 O + H P O 4 2 - + M g 2 + -5,8 (KPS) Musvoto et al. (2000), Çelen et al. (2007)

Thumbnail

M g 3 H P O 4 . 8 H 2 O ↔ 8 H 2 O + 2 P O 4 3 - + 3 M g 2 + -25,2 (KPS) Musvoto et al. (2000), Mehta e Batstone (2013), Song et al. (2015)

Thumbnail

M g 3 P O 4 2 . 8 H 2 O ↔ 8 H 2 O + 2 P O 4 3 - + 3 M g 2 + -25,2 (KPS) Musvoto et al. (2000), Mehta e Batstone (2013), Song et al. (2015)

(1)

(2)

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

(11)

(12)

(3)

(13)

(14)

(15)

(16)

(17)

(18)

(19)

(20)

(21)

(22)

(23)

(24)

(25)

(26)

(27)

(28)

(29)

(30)

(31)

(32)

(33)

(34)

(35)

(36)

(37)

[P-PO₄] (mM)	[Mg] (mM)	[N-NH₃] (mM)	[Ca] (mM)	Faixa de pH	Condições nas quais a estruvita foi formada	O que aconteceu fora dessas condições?	Escala	Meio de cristalização	Referência
1,64	1,64	3,28	0, 0,82; 1,64; 3,28	9,0	Mg:Ca > 2:1	Formou apenas “fosfato de cálcio amorfo”	laboratório	Água ultrapura com íons CO₃adicionados	*Le Corre et al. (2005*LE CORRE, K.S.; VALSAMI-JONES, E.; HOBBS, P.; PARSONS, S.A. (2005) Impact of calcium on struvite crystal size, shape and purity. Journal of Crystal Growth, v. 283, n. 3-4, p. 514-522. https://doi.org/10.1016/j.jcrysgro.2005.06.012 https://doi.org/10.1016/j.jcrysgro.2005.... )
6,13	3,07; 6,13; 12,26	122,6	3,07; 6,13; 12,26	7,8; 8,7; 9,2; 10,5	8,0 < pH < 9,0 e P:Ca > 2:1	Formou apenas “fosfato de cálcio” amorfo	laboratório	Efluente de criadouros de animais confinados	*Wang et al. (2005*WANG, J.; BURKEN, J.G.; ZHANG, X.; SURAMPALLI, R. (2005) Engineered struvite precipitation: Impacts of component-ion molar ratios and pH. Journal of Environmental Engineering, v. 131, n. 10, p. 1433-1440. https://doi.org/10.1061/(ASCE)0733-9372(2005)131:10(1433) https://doi.org/10.1061/(ASCE)0733-9372(... )
2,58	3,61	20,63	1,81; 3,61; 7,22	9,5	Mg:Ca > 2:1	A formação de estruvita foi inibida, para pH > 11, formou apenas MgOH₂	laboratório	Efluente sintético de criadouro de porco	*Song et al.* (2007**SONG, Y.; YUAN, P.; ZHENG, B.; PENG, J.; YUAN, F.; GAO, Y. (2007) Nutrients removal and recovery by crystallization of magnesium ammonium phosphate from synthetic swine wastewater. Chemosphere, v. 69, n. 2, p. 319-324. https://doi.org/10.1016/j.chemosphere.2007.06.001 https://doi.org/10.1016/j.chemosphere.20... )
3,0	2,5	7,5	2,17	7,5; 8,5; 9,5; 10,5; 11,5	Para qualquer pH < 10,5; mesmo para Mg:Ca = 1,2	Formaram Ca₃PO₄, CaHPO₄, Mg₃PO₄ ou MgOH₂ amorfos	laboratório	Água de torneira com alta concentração de Ca	*Hao et al. (2008*HAO, X.D.; WANG, C.; LAN, L.; VAN LOOSDRECHT, M.C.M. (2008) Struvite formation, analytical methods and effects of pH and Ca 2+. Water Science and Technology, v. 58, n. 8, p. 1687-1692. https://doi.org/10.2166/wst.2008.557 https://doi.org/10.2166/wst.2008.557... )
2,2; 2,0; 2,7	24,6; 19,9; 20,8 respectivamente	2,2; 2,1; 12,0 respectivamente	4;8; 3,9; 4,1 respectivamente	7,79; 9,57; 7,86 respectivamente	pH = 7,86 e N:P = 4; concluíram que o Ca não influencia na formação da estruvita	Formou Mg₃(PO₄)₂.10H₂O com material amorfo para pH = 7,79; e fosfatos de Mg e Ca para pH = 9,57	piloto	Efluente de indústria de peixes congelados	Crutchik e Garrido (2011CRUTCHIK, D.; GARRIDO, J.M. (2011) Struvite crystallization versus amorphous magnesium and calcium phosphate precipitation during the treatment of a saline industrial wastewater. Water Science and Technology, v. 64, n. 12, p. 2460-2467. https://doi.org/10.2166/wst.2011.836 https://doi.org/10.2166/wst.2011.836... )
10,7	17,5	38,7	20,0	7,0 a 10,0	pH = 9,0 em relação de atividades Ca²:Mg²⁺ < 0,2:1	Somente carbonato de cálcio precipitou na água residuária real (filtrado do digestor anaeróbio de uma indústria de laticínios) em pH 9,0 a 10,0	laboratório	Solução sintética para avaliar efeito do cálcio e real para determinar remoção de cálcio	Huchzermeier e Tao (2012HUCHZERMEIER, M.P.; TAO, W. (2012) Overcoming Challenges to Struvite Recovery from Anaerobically Digested Dairy Manure. Water Environment Research, v. 84, n. 1, p. 34-41.)
15,5	0 a 9,6	7,0	0 a 16,0	5,07 a 10,93	Em pH > 7,9 e Mg:Ca > 4:1 obtém-se estruvita com alta pureza (> 98%)	Hidroxiapatita - em Mg:Ca < 1:9 e 8,0 < pH < 10,5; brushita - em pH < 6,5 e Mg:Ca < 4:1; Newberita - em pH < 6,0 e Mg:Ca > 4:1; monetita - CaHPO₄ em pH < 6,5 e Mg:Ca < 1:4; whitloquita - em 6,5 < pH > 8,5 e Mg:Ca de 4:1 a 1:4	Laboratório	Mistura de soluções de MgCl₂; CaCl₂; NH₄Cl, Na₃PO₄ e NaH₂PO₄ 0,1 M	*Muster et al. (2013*MUSTER, T.H.; DOUGLAS, G.B.; SHERMAN, N.; SEEBER, A.; WRIGHT, N.; GÜZÜKARA, Y. (2013) Towards effective phosphorus recycling from wastewater: Quantity and quality. Chemosphere, v. 91, n. 5, p. 676-684. https://doi.org/10.1016/j.chemosphere.2013.01.057 https://doi.org/10.1016/j.chemosphere.20... )
16,7	16,7	16,7	3,3; 5,6; 8,4; 16,7; 20,9 e 33,4 respectivamente	7,5; 8,0; 9,0; 10,0 e 11,0	Todas, mas com diferentes purezas. O aumento da relação Ca:Mg e do pH ocasionou redução na pureza.	A porcentagem de estruvita era menor que 50% em Ca:Mg ≥ 1:1 e em pH ≥ 10,0. O outro precipitado formado era hidroxiapatita em valores de pH 7,5 e 8,0. Em pH 10,0 e 11,0, forma-se fosfato de cálcio amorfo e Mg₃PO₄.22H₂O e Mg₃PO₄.6H₂O	laboratório	Água desionizada com adição de cloreto de cálcio e cloreto férrico	Yan e Shih (2016YAN, H.; SHIH, K. (2016) Effects of calcium and ferric ions on struvite precipitation: A new assessment based on quantitative X-ray diffraction analysis. Water Research, v. 95, p. 310-318. https://doi.org/10.1016/j.watres.2016.03.032 https://doi.org/10.1016/j.watres.2016.03... )

Reação	logk ou logK_PS onde especificado	Referência
$H_{2} O \leftrightarrow H^{+} + {O H}^{-}$	14,0	Bhuyian, Mavinic e Beckie (2007BHUYIAN, M.I.H.; MAVINIC, D.S.; BECKIE, R.D. (2007) A Solubility and thermodynamic study of struvite. Environmental Technology, v. 28, n. 9, p. 1015-1026. https://doi.org/10.1080/09593332808618857 https://doi.org/10.1080/0959333280861885... ), Babic-Ivancic et al. (2002BABIC-IVANCIC, V.; KONTREC, J.; KRALJ, D.; BRECEVIC, L. (2002) Precipitation diagrams of struvite and dissolution kinetics of different struvite morphologies. Croatica Chemica Acta, v. 75, n. 1, p. 89-106.), *Hanhoun et al.* (2011HANHOUN, M.; MONTASTRUC, L.; AZZARO-PANTEL, C.; BISCANS, B.; FRECHE, M.; PIBOULEAU, L. (2011) Temperature impact assessment on struvite solubility product : a thermodynamic modeling approach. Chemical Engineering Journal, v. 167, n. 1, p. 50-58. http://dx.doi.org/10.1016/j.cej.2010.12.001 http://dx.doi.org/10.1016/j.cej.2010.12.... ), Rahaman et al. (2014**RAHAMAN, M.S.; MAVINIC, D.S.; MEIKLEHAM, A.; ELLIS, N. (2014) Modeling phosphorus removal and recovery from anaerobic digester supernatant through struvite crystallization in a fluidized bed reactor. Water Research, v. 51, p. 1-10. https://doi.org/10.1016/j.watres.2013.11.048 https://doi.org/10.1016/j.watres.2013.11... )
${{N H}_{3} + H^{+} \leftrightarrow N H}_{4}^{+}$	9,24	Webb e Ho (1991WEBB, K.M.; HO, G.E. (1991) Struvite (MgNH4PO4.6H2O) solubility and its application to a piggery effluent problem. In: WORKSHOP ON APPROPRIATE TECHNOLOGY FOR ENVIRONMENTALLY SUSTAINABLE DEVELOPMENT. Anais… ASEAN, Perth, Australia: Remote Area Developments Group, p. 39-45.), Babic-Ivancic et al. (2002BABIC-IVANCIC, V.; KONTREC, J.; KRALJ, D.; BRECEVIC, L. (2002) Precipitation diagrams of struvite and dissolution kinetics of different struvite morphologies. Croatica Chemica Acta, v. 75, n. 1, p. 89-106.), Bhuyian, Mavinic e Beckie (2007BHUYIAN, M.I.H.; MAVINIC, D.S.; BECKIE, R.D. (2007) A Solubility and thermodynamic study of struvite. Environmental Technology, v. 28, n. 9, p. 1015-1026. https://doi.org/10.1080/09593332808618857 https://doi.org/10.1080/0959333280861885... ), Doyle e Parsons (2002DOYLE, J.D.; PARSONS, S.A. (2002) Struvite formation, control and recovery. Water Research, v. 36, n. 16, p. 3925-3940.), Bouropoulos e Koutsoukos (2000BOUROPOULOS, N.C.; KOUTSOUKOS, P.G. (2000) Spontaneous precipitation of struvite from aqueous solutions. Journal of Crystal Growth, v. 213, n. 3-4, p. 381-388.), Ronteltap, Maurer e Gujer (2007RONTELTAP, M.; MAURER, M.; GUJER, W. (2007) Struvite precipitation thermodynamics in source-separated urine. Water Research, v. 41, n. 5, p. 977-984. http://dx.doi.org/10.1016/j.watres.2006.11.046 http://dx.doi.org/10.1016/j.watres.2006.... ), *Hanhoun et al.* (2011HANHOUN, M.; MONTASTRUC, L.; AZZARO-PANTEL, C.; BISCANS, B.; FRECHE, M.; PIBOULEAU, L. (2011) Temperature impact assessment on struvite solubility product : a thermodynamic modeling approach. Chemical Engineering Journal, v. 167, n. 1, p. 50-58. http://dx.doi.org/10.1016/j.cej.2010.12.001 http://dx.doi.org/10.1016/j.cej.2010.12.... ), Rahaman et al. (2014**RAHAMAN, M.S.; MAVINIC, D.S.; MEIKLEHAM, A.; ELLIS, N. (2014) Modeling phosphorus removal and recovery from anaerobic digester supernatant through struvite crystallization in a fluidized bed reactor. Water Research, v. 51, p. 1-10. https://doi.org/10.1016/j.watres.2013.11.048 https://doi.org/10.1016/j.watres.2013.11... )
${{H C O}_{3}^{-} \leftrightarrow C O}_{3}^{2 -} + H^{+}$	-10,33	Ronteltap, Maurer e Gujer (2007RONTELTAP, M.; MAURER, M.; GUJER, W. (2007) Struvite precipitation thermodynamics in source-separated urine. Water Research, v. 41, n. 5, p. 977-984. http://dx.doi.org/10.1016/j.watres.2006.11.046 http://dx.doi.org/10.1016/j.watres.2006.... )
$H^{+} + {P O}_{4}^{3 -} \leftrightarrow {H P O}_{4}^{2 -}$	12,32	Webb e Ho (1991WEBB, K.M.; HO, G.E. (1991) Struvite (MgNH4PO4.6H2O) solubility and its application to a piggery effluent problem. In: WORKSHOP ON APPROPRIATE TECHNOLOGY FOR ENVIRONMENTALLY SUSTAINABLE DEVELOPMENT. Anais… ASEAN, Perth, Australia: Remote Area Developments Group, p. 39-45.), Bhuyian, Mavinic e Beckie (2007BHUYIAN, M.I.H.; MAVINIC, D.S.; BECKIE, R.D. (2007) A Solubility and thermodynamic study of struvite. Environmental Technology, v. 28, n. 9, p. 1015-1026. https://doi.org/10.1080/09593332808618857 https://doi.org/10.1080/0959333280861885... ), Babic-Ivancic et al. (2002BABIC-IVANCIC, V.; KONTREC, J.; KRALJ, D.; BRECEVIC, L. (2002) Precipitation diagrams of struvite and dissolution kinetics of different struvite morphologies. Croatica Chemica Acta, v. 75, n. 1, p. 89-106.), Doyle e Parsons (2002DOYLE, J.D.; PARSONS, S.A. (2002) Struvite formation, control and recovery. Water Research, v. 36, n. 16, p. 3925-3940.), Ronteltap, Maurer e Gujer (2007RONTELTAP, M.; MAURER, M.; GUJER, W. (2007) Struvite precipitation thermodynamics in source-separated urine. Water Research, v. 41, n. 5, p. 977-984. http://dx.doi.org/10.1016/j.watres.2006.11.046 http://dx.doi.org/10.1016/j.watres.2006.... ), *Hanhoun et al.* (2011HANHOUN, M.; MONTASTRUC, L.; AZZARO-PANTEL, C.; BISCANS, B.; FRECHE, M.; PIBOULEAU, L. (2011) Temperature impact assessment on struvite solubility product : a thermodynamic modeling approach. Chemical Engineering Journal, v. 167, n. 1, p. 50-58. http://dx.doi.org/10.1016/j.cej.2010.12.001 http://dx.doi.org/10.1016/j.cej.2010.12.... ), Rahaman et al. (2014**RAHAMAN, M.S.; MAVINIC, D.S.; MEIKLEHAM, A.; ELLIS, N. (2014) Modeling phosphorus removal and recovery from anaerobic digester supernatant through struvite crystallization in a fluidized bed reactor. Water Research, v. 51, p. 1-10. https://doi.org/10.1016/j.watres.2013.11.048 https://doi.org/10.1016/j.watres.2013.11... )
$H_{3} {P O}_{4} \leftrightarrow H_{2} {P O}_{4}^{-} + H^{+}$	-2,1	Webb e Ho (1991WEBB, K.M.; HO, G.E. (1991) Struvite (MgNH4PO4.6H2O) solubility and its application to a piggery effluent problem. In: WORKSHOP ON APPROPRIATE TECHNOLOGY FOR ENVIRONMENTALLY SUSTAINABLE DEVELOPMENT. Anais… ASEAN, Perth, Australia: Remote Area Developments Group, p. 39-45.), Bouropoulos e Koutsoukos (2000BOUROPOULOS, N.C.; KOUTSOUKOS, P.G. (2000) Spontaneous precipitation of struvite from aqueous solutions. Journal of Crystal Growth, v. 213, n. 3-4, p. 381-388.), Babic-Ivancic et al. (2002BABIC-IVANCIC, V.; KONTREC, J.; KRALJ, D.; BRECEVIC, L. (2002) Precipitation diagrams of struvite and dissolution kinetics of different struvite morphologies. Croatica Chemica Acta, v. 75, n. 1, p. 89-106.), *Hanhoun et al.* (2011HANHOUN, M.; MONTASTRUC, L.; AZZARO-PANTEL, C.; BISCANS, B.; FRECHE, M.; PIBOULEAU, L. (2011) Temperature impact assessment on struvite solubility product : a thermodynamic modeling approach. Chemical Engineering Journal, v. 167, n. 1, p. 50-58. http://dx.doi.org/10.1016/j.cej.2010.12.001 http://dx.doi.org/10.1016/j.cej.2010.12.... ), Rahaman et al. (2014**RAHAMAN, M.S.; MAVINIC, D.S.; MEIKLEHAM, A.; ELLIS, N. (2014) Modeling phosphorus removal and recovery from anaerobic digester supernatant through struvite crystallization in a fluidized bed reactor. Water Research, v. 51, p. 1-10. https://doi.org/10.1016/j.watres.2013.11.048 https://doi.org/10.1016/j.watres.2013.11... )
${H P O}_{4}^{2 -} + 2 H^{+} \leftrightarrow H_{3} {P O}_{4}$	9,37	Bhuyian, Mavinic e Beckie (2007BHUYIAN, M.I.H.; MAVINIC, D.S.; BECKIE, R.D. (2007) A Solubility and thermodynamic study of struvite. Environmental Technology, v. 28, n. 9, p. 1015-1026. https://doi.org/10.1080/09593332808618857 https://doi.org/10.1080/0959333280861885... )
${H P O}_{4}^{2 -} + H^{+} \leftrightarrow H_{2} {P O}_{4}^{-}$	7,20	Webb e Ho (1991WEBB, K.M.; HO, G.E. (1991) Struvite (MgNH4PO4.6H2O) solubility and its application to a piggery effluent problem. In: WORKSHOP ON APPROPRIATE TECHNOLOGY FOR ENVIRONMENTALLY SUSTAINABLE DEVELOPMENT. Anais… ASEAN, Perth, Australia: Remote Area Developments Group, p. 39-45.), Bhuyian, Mavinic e Beckie (2007BHUYIAN, M.I.H.; MAVINIC, D.S.; BECKIE, R.D. (2007) A Solubility and thermodynamic study of struvite. Environmental Technology, v. 28, n. 9, p. 1015-1026. https://doi.org/10.1080/09593332808618857 https://doi.org/10.1080/0959333280861885... ), Bouropoulos e Koutsoukos (2000BOUROPOULOS, N.C.; KOUTSOUKOS, P.G. (2000) Spontaneous precipitation of struvite from aqueous solutions. Journal of Crystal Growth, v. 213, n. 3-4, p. 381-388.), Babic-Ivancic et al. (2002BABIC-IVANCIC, V.; KONTREC, J.; KRALJ, D.; BRECEVIC, L. (2002) Precipitation diagrams of struvite and dissolution kinetics of different struvite morphologies. Croatica Chemica Acta, v. 75, n. 1, p. 89-106.), Doyle e Parsons (2002DOYLE, J.D.; PARSONS, S.A. (2002) Struvite formation, control and recovery. Water Research, v. 36, n. 16, p. 3925-3940.), Ronteltap, Maurer e Gujer (2007RONTELTAP, M.; MAURER, M.; GUJER, W. (2007) Struvite precipitation thermodynamics in source-separated urine. Water Research, v. 41, n. 5, p. 977-984. http://dx.doi.org/10.1016/j.watres.2006.11.046 http://dx.doi.org/10.1016/j.watres.2006.... ), *Hanhoun et al.* (2011HANHOUN, M.; MONTASTRUC, L.; AZZARO-PANTEL, C.; BISCANS, B.; FRECHE, M.; PIBOULEAU, L. (2011) Temperature impact assessment on struvite solubility product : a thermodynamic modeling approach. Chemical Engineering Journal, v. 167, n. 1, p. 50-58. http://dx.doi.org/10.1016/j.cej.2010.12.001 http://dx.doi.org/10.1016/j.cej.2010.12.... ), Rahaman et al. (2014**RAHAMAN, M.S.; MAVINIC, D.S.; MEIKLEHAM, A.; ELLIS, N. (2014) Modeling phosphorus removal and recovery from anaerobic digester supernatant through struvite crystallization in a fluidized bed reactor. Water Research, v. 51, p. 1-10. https://doi.org/10.1016/j.watres.2013.11.048 https://doi.org/10.1016/j.watres.2013.11... )
${S O}_{4}^{2 -} + H^{+} \leftrightarrow {H S O}_{4}^{-}$	1,99	Babic-Ivancic et al. (2002BABIC-IVANCIC, V.; KONTREC, J.; KRALJ, D.; BRECEVIC, L. (2002) Precipitation diagrams of struvite and dissolution kinetics of different struvite morphologies. Croatica Chemica Acta, v. 75, n. 1, p. 89-106.)
$C a ({O H)}_{2} \leftrightarrow {C a}^{2 +} + 2 {O H}^{-}$	-5,2	*Musvoto et al. (2000MUSVOTO, E.V.; EKAMA, G.A.; WENTZEL, M.C.; LOEWWENTHAL, R.E. (2000) Extension and application of the three-phase weak acid/base kinetic model to the aeration treatment of anaerobic digester liquors. Water SA, v. 26, n. 4, p. 417-438.), Mehta e Batstone (2013*MEHTA, C.M.; BATSTONE, D.J. (2013) Nucleation and growth kinetics of struvite crystallization. Water Research, v. 47, n. 8, p. 2890-2900. https://doi.org/10.1016/j.watres.2013.03.007 https://doi.org/10.1016/j.watres.2013.03... )
$M g ({O H}_{2}) . 6 H_{2} O \leftrightarrow 6 H_{2} O + {M g}^{2 +} + 2 {O H}^{-}$	-10,9 (K_PS)	Mehta e Batstone (2013MEHTA, C.M.; BATSTONE, D.J. (2013) Nucleation and growth kinetics of struvite crystallization. Water Research, v. 47, n. 8, p. 2890-2900. https://doi.org/10.1016/j.watres.2013.03.007 https://doi.org/10.1016/j.watres.2013.03... )
$M g ({O H)}_{2} \leftrightarrow {M g}^{2 +} + 2 {O H}^{-}$	-11,16 (K_PS)	*Musvoto et al.* (2000MUSVOTO, E.V.; EKAMA, G.A.; WENTZEL, M.C.; LOEWWENTHAL, R.E. (2000) Extension and application of the three-phase weak acid/base kinetic model to the aeration treatment of anaerobic digester liquors. Water SA, v. 26, n. 4, p. 417-438.), Çelen et al. (2007**ÇELEN, I.; BUCHANAN, J.R.; BURNS, R.T.; ROBINSON, R.B.; RAMAN, D.R. (2007) Using a chemical equilibrium model to predict amendments required to precipitate phosphorus as struvite in liquid swine manure. Water Research, v. 41, n. 8, p. 1689-1696. https://doi.org/10.1016/j.watres.2007.01.018 https://doi.org/10.1016/j.watres.2007.01... )
${M g}^{2 +} + {O H}^{-} \leftrightarrow M g {O H}^{+}$	2,6	Bouropoulos e Koutsoukos (2000BOUROPOULOS, N.C.; KOUTSOUKOS, P.G. (2000) Spontaneous precipitation of struvite from aqueous solutions. Journal of Crystal Growth, v. 213, n. 3-4, p. 381-388.), Doyle e Parsons (2002DOYLE, J.D.; PARSONS, S.A. (2002) Struvite formation, control and recovery. Water Research, v. 36, n. 16, p. 3925-3940.), *Hanhoun et al.* (2011HANHOUN, M.; MONTASTRUC, L.; AZZARO-PANTEL, C.; BISCANS, B.; FRECHE, M.; PIBOULEAU, L. (2011) Temperature impact assessment on struvite solubility product : a thermodynamic modeling approach. Chemical Engineering Journal, v. 167, n. 1, p. 50-58. http://dx.doi.org/10.1016/j.cej.2010.12.001 http://dx.doi.org/10.1016/j.cej.2010.12.... ), Rahaman et al. (2014**RAHAMAN, M.S.; MAVINIC, D.S.; MEIKLEHAM, A.; ELLIS, N. (2014) Modeling phosphorus removal and recovery from anaerobic digester supernatant through struvite crystallization in a fluidized bed reactor. Water Research, v. 51, p. 1-10. https://doi.org/10.1016/j.watres.2013.11.048 https://doi.org/10.1016/j.watres.2013.11... )
${M g}^{2 +} + H_{2} O \leftrightarrow {M g O H}^{+} + H^{+}$	-11,44	Webb e Ho (1991WEBB, K.M.; HO, G.E. (1991) Struvite (MgNH4PO4.6H2O) solubility and its application to a piggery effluent problem. In: WORKSHOP ON APPROPRIATE TECHNOLOGY FOR ENVIRONMENTALLY SUSTAINABLE DEVELOPMENT. Anais… ASEAN, Perth, Australia: Remote Area Developments Group, p. 39-45.), Bhuyian, Mavinic e Beckie (2007BHUYIAN, M.I.H.; MAVINIC, D.S.; BECKIE, R.D. (2007) A Solubility and thermodynamic study of struvite. Environmental Technology, v. 28, n. 9, p. 1015-1026. https://doi.org/10.1080/09593332808618857 https://doi.org/10.1080/0959333280861885... )
${C a}_{10} ({{P O}_{4})}_{6} ({O H)}_{2} \leftrightarrow 10 {C a}^{2 +} + 6 {P O}_{4}^{3 -} + 2 {O H}^{-}$	-114 (K_PS)	*Musvoto et al.* (2000**MUSVOTO, E.V.; EKAMA, G.A.; WENTZEL, M.C.; LOEWWENTHAL, R.E. (2000) Extension and application of the three-phase weak acid/base kinetic model to the aeration treatment of anaerobic digester liquors. Water SA, v. 26, n. 4, p. 417-438.)
${C a}_{3} {{(P O}_{4})}_{2} . x H_{2} O \leftrightarrow 3 {C a}^{2 +} + 2 {P O}_{4}^{3} + x H_{2} O$	-31,45 (K_PS)	*Musvoto et al.* (2000**MUSVOTO, E.V.; EKAMA, G.A.; WENTZEL, M.C.; LOEWWENTHAL, R.E. (2000) Extension and application of the three-phase weak acid/base kinetic model to the aeration treatment of anaerobic digester liquors. Water SA, v. 26, n. 4, p. 417-438.)
${C a}_{3} {{(P O}_{4})}_{2} \leftrightarrow 3 {C a}^{2 +} + 2 {P O}_{4}^{3 -}$	-32,7 (K_PS)	*Musvoto et al.* (2000MUSVOTO, E.V.; EKAMA, G.A.; WENTZEL, M.C.; LOEWWENTHAL, R.E. (2000) Extension and application of the three-phase weak acid/base kinetic model to the aeration treatment of anaerobic digester liquors. Water SA, v. 26, n. 4, p. 417-438.), Mehta e Batstone (2013**MEHTA, C.M.; BATSTONE, D.J. (2013) Nucleation and growth kinetics of struvite crystallization. Water Research, v. 47, n. 8, p. 2890-2900. https://doi.org/10.1016/j.watres.2013.03.007 https://doi.org/10.1016/j.watres.2013.03... )
${C a}_{8} (H {{P O}_{4})}_{2} ({{P O}_{4})}_{4} 5 H_{2} O \leftrightarrow 8 {C a}^{2 +} + 2 H {P O}_{4}^{2 -} + 4 {P O}_{4}^{3 -} + 5 H_{2} O$	-94,16 (K_PS)	*Musvoto et al.* (2000**MUSVOTO, E.V.; EKAMA, G.A.; WENTZEL, M.C.; LOEWWENTHAL, R.E. (2000) Extension and application of the three-phase weak acid/base kinetic model to the aeration treatment of anaerobic digester liquors. Water SA, v. 26, n. 4, p. 417-438.)
$C a {H P O}_{4} \leftrightarrow {C a}^{2 +} + {H P O}_{4}^{2 -}$	-2,7 (K_PS)	*Musvoto et al. (2000*MUSVOTO, E.V.; EKAMA, G.A.; WENTZEL, M.C.; LOEWWENTHAL, R.E. (2000) Extension and application of the three-phase weak acid/base kinetic model to the aeration treatment of anaerobic digester liquors. Water SA, v. 26, n. 4, p. 417-438.)
$C a {H P O}_{4} . 2 H_{2} O \leftrightarrow {C a}^{2 +} + {H P O}_{4}^{2 -} + 2 H_{2} O$	-6,6 (K_PS)	*Musvoto et al.* (2000MUSVOTO, E.V.; EKAMA, G.A.; WENTZEL, M.C.; LOEWWENTHAL, R.E. (2000) Extension and application of the three-phase weak acid/base kinetic model to the aeration treatment of anaerobic digester liquors. Water SA, v. 26, n. 4, p. 417-438.), Mehta e Batstone (2013**MEHTA, C.M.; BATSTONE, D.J. (2013) Nucleation and growth kinetics of struvite crystallization. Water Research, v. 47, n. 8, p. 2890-2900. https://doi.org/10.1016/j.watres.2013.03.007 https://doi.org/10.1016/j.watres.2013.03... )
${C a}_{5} ({{P O}_{4})}_{3} (O H) \leftrightarrow 5 {C a}^{2 +} + 3 {P O}_{4}^{3 -} + {O H}^{-}$	-57,8 (K_PS)	*Muster et al.* (2013**MUSTER, T.H.; DOUGLAS, G.B.; SHERMAN, N.; SEEBER, A.; WRIGHT, N.; GÜZÜKARA, Y. (2013) Towards effective phosphorus recycling from wastewater: Quantity and quality. Chemosphere, v. 91, n. 5, p. 676-684. https://doi.org/10.1016/j.chemosphere.2013.01.057 https://doi.org/10.1016/j.chemosphere.20... )
$H_{2} {P O}_{4}^{-} + {M g}^{2 +} \leftrightarrow M g H_{2} {P O}_{4}^{+}$	0,45	Bhuyian, Mavinic e Beckie (2007BHUYIAN, M.I.H.; MAVINIC, D.S.; BECKIE, R.D. (2007) A Solubility and thermodynamic study of struvite. Environmental Technology, v. 28, n. 9, p. 1015-1026. https://doi.org/10.1080/09593332808618857 https://doi.org/10.1080/0959333280861885... ), Bouropoulos e Koutsoukos (2000BOUROPOULOS, N.C.; KOUTSOUKOS, P.G. (2000) Spontaneous precipitation of struvite from aqueous solutions. Journal of Crystal Growth, v. 213, n. 3-4, p. 381-388.), Babic-Ivancic et al. (2002BABIC-IVANCIC, V.; KONTREC, J.; KRALJ, D.; BRECEVIC, L. (2002) Precipitation diagrams of struvite and dissolution kinetics of different struvite morphologies. Croatica Chemica Acta, v. 75, n. 1, p. 89-106.), Doyle e Parsons (2002DOYLE, J.D.; PARSONS, S.A. (2002) Struvite formation, control and recovery. Water Research, v. 36, n. 16, p. 3925-3940.), *Hanhoun et al.* (2011HANHOUN, M.; MONTASTRUC, L.; AZZARO-PANTEL, C.; BISCANS, B.; FRECHE, M.; PIBOULEAU, L. (2011) Temperature impact assessment on struvite solubility product : a thermodynamic modeling approach. Chemical Engineering Journal, v. 167, n. 1, p. 50-58. http://dx.doi.org/10.1016/j.cej.2010.12.001 http://dx.doi.org/10.1016/j.cej.2010.12.... ), Rahaman et al. (2014**RAHAMAN, M.S.; MAVINIC, D.S.; MEIKLEHAM, A.; ELLIS, N. (2014) Modeling phosphorus removal and recovery from anaerobic digester supernatant through struvite crystallization in a fluidized bed reactor. Water Research, v. 51, p. 1-10. https://doi.org/10.1016/j.watres.2013.11.048 https://doi.org/10.1016/j.watres.2013.11... )
$H_{2} {P O}_{4}^{-} + {M g}^{2 +} \leftrightarrow M g {P O}_{4}^{-} + 2 H^{+}$	-12,96	Ronteltap, Maurer e Gujer (2007RONTELTAP, M.; MAURER, M.; GUJER, W. (2007) Struvite precipitation thermodynamics in source-separated urine. Water Research, v. 41, n. 5, p. 977-984. http://dx.doi.org/10.1016/j.watres.2006.11.046 http://dx.doi.org/10.1016/j.watres.2006.... )
$H_{2} {P O}_{4}^{-} + {M g}^{2 +} \leftrightarrow M g H {P O}_{4} + H^{+}$	-4,3	Ronteltap, Maurer e Gujer (2007RONTELTAP, M.; MAURER, M.; GUJER, W. (2007) Struvite precipitation thermodynamics in source-separated urine. Water Research, v. 41, n. 5, p. 977-984. http://dx.doi.org/10.1016/j.watres.2006.11.046 http://dx.doi.org/10.1016/j.watres.2006.... )
$H {P O}_{4}^{2 -} + {M g}^{2 +} \leftrightarrow M g H {P O}_{4}$	2,43	Babic-Ivancic et al. (2002BABIC-IVANCIC, V.; KONTREC, J.; KRALJ, D.; BRECEVIC, L. (2002) Precipitation diagrams of struvite and dissolution kinetics of different struvite morphologies. Croatica Chemica Acta, v. 75, n. 1, p. 89-106.), Doyle e Parsons (2002DOYLE, J.D.; PARSONS, S.A. (2002) Struvite formation, control and recovery. Water Research, v. 36, n. 16, p. 3925-3940.), *Hanhoun et al.* (2011HANHOUN, M.; MONTASTRUC, L.; AZZARO-PANTEL, C.; BISCANS, B.; FRECHE, M.; PIBOULEAU, L. (2011) Temperature impact assessment on struvite solubility product : a thermodynamic modeling approach. Chemical Engineering Journal, v. 167, n. 1, p. 50-58. http://dx.doi.org/10.1016/j.cej.2010.12.001 http://dx.doi.org/10.1016/j.cej.2010.12.... ), Rahaman et al. (2014RAHAMAN, M.S.; MAVINIC, D.S.; MEIKLEHAM, A.; ELLIS, N. (2014) Modeling phosphorus removal and recovery from anaerobic digester supernatant through struvite crystallization in a fluidized bed reactor. Water Research, v. 51, p. 1-10. https://doi.org/10.1016/j.watres.2013.11.048 https://doi.org/10.1016/j.watres.2013.11... ), Bhuyian, Mavinic e Beckie (2007BHUYIAN, M.I.H.; MAVINIC, D.S.; BECKIE, R.D. (2007) A Solubility and thermodynamic study of struvite. Environmental Technology, v. 28, n. 9, p. 1015-1026. https://doi.org/10.1080/09593332808618857 https://doi.org/10.1080/0959333280861885... ), Bouropoulos e Koutsoukos (2000**BOUROPOULOS, N.C.; KOUTSOUKOS, P.G. (2000) Spontaneous precipitation of struvite from aqueous solutions. Journal of Crystal Growth, v. 213, n. 3-4, p. 381-388.)
${P O}_{4}^{3 -} + {M g}^{2 +} \leftrightarrow M g {P O}_{4}^{-}$	4,80	Bhuyian, Mavinic e Beckie (2007BHUYIAN, M.I.H.; MAVINIC, D.S.; BECKIE, R.D. (2007) A Solubility and thermodynamic study of struvite. Environmental Technology, v. 28, n. 9, p. 1015-1026. https://doi.org/10.1080/09593332808618857 https://doi.org/10.1080/0959333280861885... ), Bouropoulos e Koutsoukos (2000BOUROPOULOS, N.C.; KOUTSOUKOS, P.G. (2000) Spontaneous precipitation of struvite from aqueous solutions. Journal of Crystal Growth, v. 213, n. 3-4, p. 381-388.), *Babic-Ivancic et al.* (2002BABIC-IVANCIC, V.; KONTREC, J.; KRALJ, D.; BRECEVIC, L. (2002) Precipitation diagrams of struvite and dissolution kinetics of different struvite morphologies. Croatica Chemica Acta, v. 75, n. 1, p. 89-106.), Doyle e Parsons (2002DOYLE, J.D.; PARSONS, S.A. (2002) Struvite formation, control and recovery. Water Research, v. 36, n. 16, p. 3925-3940.), Hanhoun et al. (2011**HANHOUN, M.; MONTASTRUC, L.; AZZARO-PANTEL, C.; BISCANS, B.; FRECHE, M.; PIBOULEAU, L. (2011) Temperature impact assessment on struvite solubility product : a thermodynamic modeling approach. Chemical Engineering Journal, v. 167, n. 1, p. 50-58. http://dx.doi.org/10.1016/j.cej.2010.12.001 http://dx.doi.org/10.1016/j.cej.2010.12.... )
${M g}_{3} {H P O}_{4} . 3 H_{2} O \leftrightarrow 3 H_{2} O + {H P O}_{4}^{2 -} + {M g}^{2 +}$	-5,8 (K_PS)	*Musvoto et al.* (2000MUSVOTO, E.V.; EKAMA, G.A.; WENTZEL, M.C.; LOEWWENTHAL, R.E. (2000) Extension and application of the three-phase weak acid/base kinetic model to the aeration treatment of anaerobic digester liquors. Water SA, v. 26, n. 4, p. 417-438.), Çelen et al. (2007**ÇELEN, I.; BUCHANAN, J.R.; BURNS, R.T.; ROBINSON, R.B.; RAMAN, D.R. (2007) Using a chemical equilibrium model to predict amendments required to precipitate phosphorus as struvite in liquid swine manure. Water Research, v. 41, n. 8, p. 1689-1696. https://doi.org/10.1016/j.watres.2007.01.018 https://doi.org/10.1016/j.watres.2007.01... )
${M g}_{3} {H P O}_{4} . 8 H_{2} O \leftrightarrow 8 H_{2} O + {2 P O}_{4}^{3 -} + {3 M g}^{2 +}$	-25,2 (K_PS)	*Musvoto et al.* (2000MUSVOTO, E.V.; EKAMA, G.A.; WENTZEL, M.C.; LOEWWENTHAL, R.E. (2000) Extension and application of the three-phase weak acid/base kinetic model to the aeration treatment of anaerobic digester liquors. Water SA, v. 26, n. 4, p. 417-438.), Mehta e Batstone (2013MEHTA, C.M.; BATSTONE, D.J. (2013) Nucleation and growth kinetics of struvite crystallization. Water Research, v. 47, n. 8, p. 2890-2900. https://doi.org/10.1016/j.watres.2013.03.007 https://doi.org/10.1016/j.watres.2013.03... ), Song et al. (2015**SONG, Y.; QIAN, F.; GAO, Y.; HUANG, X.; WU, J.; YU, H. (2015) PHREEQC program-based simulation of magnesium phosphates crystallization for phosphorus recovery. Environmental Earth Sciences, v. 73, n. 9, p. 5075-5084. https://doi.org/10.1007/s12665-015-4340-8 https://doi.org/10.1007/s12665-015-4340-... )
${M g}_{3} ({{P O}_{4})}_{2} . 22 H_{2} O \leftrightarrow 3 {M g}^{2 +} + 2 {P O}_{4}^{3 -} + 22 H_{2} O$	-23,1 (K_PS)	*Musvoto et al.* (2000MUSVOTO, E.V.; EKAMA, G.A.; WENTZEL, M.C.; LOEWWENTHAL, R.E. (2000) Extension and application of the three-phase weak acid/base kinetic model to the aeration treatment of anaerobic digester liquors. Water SA, v. 26, n. 4, p. 417-438.), Mehta e Batstone (2013MEHTA, C.M.; BATSTONE, D.J. (2013) Nucleation and growth kinetics of struvite crystallization. Water Research, v. 47, n. 8, p. 2890-2900. https://doi.org/10.1016/j.watres.2013.03.007 https://doi.org/10.1016/j.watres.2013.03... ), Song et al. (2015**SONG, Y.; QIAN, F.; GAO, Y.; HUANG, X.; WU, J.; YU, H. (2015) PHREEQC program-based simulation of magnesium phosphates crystallization for phosphorus recovery. Environmental Earth Sciences, v. 73, n. 9, p. 5075-5084. https://doi.org/10.1007/s12665-015-4340-8 https://doi.org/10.1007/s12665-015-4340-... )
${M g}^{2 +} + {N H}_{3} \leftrightarrow M g {N H}_{3}^{2 +}$	0,24*	Bhuyian, Mavinic e Beckie (2007BHUYIAN, M.I.H.; MAVINIC, D.S.; BECKIE, R.D. (2007) A Solubility and thermodynamic study of struvite. Environmental Technology, v. 28, n. 9, p. 1015-1026. https://doi.org/10.1080/09593332808618857 https://doi.org/10.1080/0959333280861885... ), Bouropoulos e Koutsoukos (2000BOUROPOULOS, N.C.; KOUTSOUKOS, P.G. (2000) Spontaneous precipitation of struvite from aqueous solutions. Journal of Crystal Growth, v. 213, n. 3-4, p. 381-388.)
${M g}^{2 +} + 2 {N H}_{3} \leftrightarrow {(M g {N H}_{3})}_{2}^{2 +}$	0,20	Bhuyian, Mavinic e Beckie (2007BHUYIAN, M.I.H.; MAVINIC, D.S.; BECKIE, R.D. (2007) A Solubility and thermodynamic study of struvite. Environmental Technology, v. 28, n. 9, p. 1015-1026. https://doi.org/10.1080/09593332808618857 https://doi.org/10.1080/0959333280861885... ), Bouropoulos e Koutsoukos (2000BOUROPOULOS, N.C.; KOUTSOUKOS, P.G. (2000) Spontaneous precipitation of struvite from aqueous solutions. Journal of Crystal Growth, v. 213, n. 3-4, p. 381-388.)
${M g}^{2 +} + 3 {N H}_{3} \leftrightarrow {(M g {N H}_{3})}_{3}^{2 +}$	-0,3*	Bhuyian, Mavinic e Beckie (2007BHUYIAN, M.I.H.; MAVINIC, D.S.; BECKIE, R.D. (2007) A Solubility and thermodynamic study of struvite. Environmental Technology, v. 28, n. 9, p. 1015-1026. https://doi.org/10.1080/09593332808618857 https://doi.org/10.1080/0959333280861885... ), Bouropoulos e Koutsoukos (2000BOUROPOULOS, N.C.; KOUTSOUKOS, P.G. (2000) Spontaneous precipitation of struvite from aqueous solutions. Journal of Crystal Growth, v. 213, n. 3-4, p. 381-388.)
${N a}^{+} + H_{2} {P O}_{4}^{-} \leftrightarrow {N a H P O}_{4}^{-} + H^{+}$	-6,01	Ronteltap, Maurer e Gujer (2007RONTELTAP, M.; MAURER, M.; GUJER, W. (2007) Struvite precipitation thermodynamics in source-separated urine. Water Research, v. 41, n. 5, p. 977-984. http://dx.doi.org/10.1016/j.watres.2006.11.046 http://dx.doi.org/10.1016/j.watres.2006.... )
${N a}^{+} + H {P O}_{4}^{2 -} \leftrightarrow N a H {P O}_{4}^{-}$	0,85	Babic-Ivancic et al. (2002BABIC-IVANCIC, V.; KONTREC, J.; KRALJ, D.; BRECEVIC, L. (2002) Precipitation diagrams of struvite and dissolution kinetics of different struvite morphologies. Croatica Chemica Acta, v. 75, n. 1, p. 89-106.)
${N H}_{4}^{+} + {H P O}_{4}^{2 -} \leftrightarrow {N H}_{4} {H P O}_{4}^{-}$	1,3	Ronteltap, Maurer e Gujer (2007RONTELTAP, M.; MAURER, M.; GUJER, W. (2007) Struvite precipitation thermodynamics in source-separated urine. Water Research, v. 41, n. 5, p. 977-984. http://dx.doi.org/10.1016/j.watres.2006.11.046 http://dx.doi.org/10.1016/j.watres.2006.... )
${N H}_{4}^{+} + {S O}_{4}^{2 -} \leftrightarrow {N H}_{4} {S O}_{4}^{-}$	1,03	Ronteltap, Maurer e Gujer (2007RONTELTAP, M.; MAURER, M.; GUJER, W. (2007) Struvite precipitation thermodynamics in source-separated urine. Water Research, v. 41, n. 5, p. 977-984. http://dx.doi.org/10.1016/j.watres.2006.11.046 http://dx.doi.org/10.1016/j.watres.2006.... )
${S O}_{4}^{2 -} + {M g}^{2 +} \leftrightarrow M g {S O}_{4}$	2,37	Bhuyian, Mavinic e Beckie (2007BHUYIAN, M.I.H.; MAVINIC, D.S.; BECKIE, R.D. (2007) A Solubility and thermodynamic study of struvite. Environmental Technology, v. 28, n. 9, p. 1015-1026. https://doi.org/10.1080/09593332808618857 https://doi.org/10.1080/0959333280861885... ), Babic-Ivancic et al. (2002BABIC-IVANCIC, V.; KONTREC, J.; KRALJ, D.; BRECEVIC, L. (2002) Precipitation diagrams of struvite and dissolution kinetics of different struvite morphologies. Croatica Chemica Acta, v. 75, n. 1, p. 89-106.)
${M g}^{2 +} + {N H}_{4}^{+} + {P O 4}_{3}^{-} + 6 H_{2} O \leftrightarrow M g {N H}_{4} {P O}_{4} . 6 H_{2} O$	13,26	Webb e Ho (1991WEBB, K.M.; HO, G.E. (1991) Struvite (MgNH4PO4.6H2O) solubility and its application to a piggery effluent problem. In: WORKSHOP ON APPROPRIATE TECHNOLOGY FOR ENVIRONMENTALLY SUSTAINABLE DEVELOPMENT. Anais… ASEAN, Perth, Australia: Remote Area Developments Group, p. 39-45.), Bouropoulos e Koutsoukos (2000BOUROPOULOS, N.C.; KOUTSOUKOS, P.G. (2000) Spontaneous precipitation of struvite from aqueous solutions. Journal of Crystal Growth, v. 213, n. 3-4, p. 381-388.), *Musvoto et al.* (2000MUSVOTO, E.V.; EKAMA, G.A.; WENTZEL, M.C.; LOEWWENTHAL, R.E. (2000) Extension and application of the three-phase weak acid/base kinetic model to the aeration treatment of anaerobic digester liquors. Water SA, v. 26, n. 4, p. 417-438.), Mehta e Batstone (2013MEHTA, C.M.; BATSTONE, D.J. (2013) Nucleation and growth kinetics of struvite crystallization. Water Research, v. 47, n. 8, p. 2890-2900. https://doi.org/10.1016/j.watres.2013.03.007 https://doi.org/10.1016/j.watres.2013.03... ), Song et al. (2015**SONG, Y.; QIAN, F.; GAO, Y.; HUANG, X.; WU, J.; YU, H. (2015) PHREEQC program-based simulation of magnesium phosphates crystallization for phosphorus recovery. Environmental Earth Sciences, v. 73, n. 9, p. 5075-5084. https://doi.org/10.1007/s12665-015-4340-8 https://doi.org/10.1007/s12665-015-4340-... )
$C a {C O}_{3} \leftrightarrow {C a}^{2 +} + {C O}_{3}^{2 -}$	-8,22 (K_PS)	*Musvoto et al.* (2000**MUSVOTO, E.V.; EKAMA, G.A.; WENTZEL, M.C.; LOEWWENTHAL, R.E. (2000) Extension and application of the three-phase weak acid/base kinetic model to the aeration treatment of anaerobic digester liquors. Water SA, v. 26, n. 4, p. 417-438.)
$C a M g {{(C O}_{3})}_{2} \leftrightarrow {C a}^{2 +} + {M g}^{2 +} + 2 {C O}_{3}^{2 -}$	-16,7 (K_PS)	*Musvoto et al.* (2000**MUSVOTO, E.V.; EKAMA, G.A.; WENTZEL, M.C.; LOEWWENTHAL, R.E. (2000) Extension and application of the three-phase weak acid/base kinetic model to the aeration treatment of anaerobic digester liquors. Water SA, v. 26, n. 4, p. 417-438.)
$M g {C O}_{3} . 3 H_{2} O \leftrightarrow {M g}^{2 +} + {C O}_{3}^{2 -} + 3 H_{2} O$	-5,19 (K_PS)	*Musvoto et al.* (2000MUSVOTO, E.V.; EKAMA, G.A.; WENTZEL, M.C.; LOEWWENTHAL, R.E. (2000) Extension and application of the three-phase weak acid/base kinetic model to the aeration treatment of anaerobic digester liquors. Water SA, v. 26, n. 4, p. 417-438.), Çelen et al. (2007**ÇELEN, I.; BUCHANAN, J.R.; BURNS, R.T.; ROBINSON, R.B.; RAMAN, D.R. (2007) Using a chemical equilibrium model to predict amendments required to precipitate phosphorus as struvite in liquid swine manure. Water Research, v. 41, n. 8, p. 1689-1696. https://doi.org/10.1016/j.watres.2007.01.018 https://doi.org/10.1016/j.watres.2007.01... )
$H {C O}_{3}^{-} + {M g}^{2 +} \leftrightarrow M g H {C O}_{3}^{+}$	1,07	Bhuyian, Mavinic e Beckie (2007BHUYIAN, M.I.H.; MAVINIC, D.S.; BECKIE, R.D. (2007) A Solubility and thermodynamic study of struvite. Environmental Technology, v. 28, n. 9, p. 1015-1026. https://doi.org/10.1080/09593332808618857 https://doi.org/10.1080/0959333280861885... ) e Ronteltap, Maurer e Gujer (2007RONTELTAP, M.; MAURER, M.; GUJER, W. (2007) Struvite precipitation thermodynamics in source-separated urine. Water Research, v. 41, n. 5, p. 977-984. http://dx.doi.org/10.1016/j.watres.2006.11.046 http://dx.doi.org/10.1016/j.watres.2006.... )
${M g}^{2 +} + {H C O}_{3}^{-} \leftrightarrow {M g C O}_{3} + H^{+}$	-7,35	Ronteltap, Maurer e Gujer (2007RONTELTAP, M.; MAURER, M.; GUJER, W. (2007) Struvite precipitation thermodynamics in source-separated urine. Water Research, v. 41, n. 5, p. 977-984. http://dx.doi.org/10.1016/j.watres.2006.11.046 http://dx.doi.org/10.1016/j.watres.2006.... )
${C O}_{3}^{2 -} + {M g}^{2 +} \leftrightarrow M g {C O}_{3}$	-8,2	*Musvoto et al.* (2000MUSVOTO, E.V.; EKAMA, G.A.; WENTZEL, M.C.; LOEWWENTHAL, R.E. (2000) Extension and application of the three-phase weak acid/base kinetic model to the aeration treatment of anaerobic digester liquors. Water SA, v. 26, n. 4, p. 417-438.), Bhuyian, Mavinic e Beckie (2007**BHUYIAN, M.I.H.; MAVINIC, D.S.; BECKIE, R.D. (2007) A Solubility and thermodynamic study of struvite. Environmental Technology, v. 28, n. 9, p. 1015-1026. https://doi.org/10.1080/09593332808618857 https://doi.org/10.1080/0959333280861885... )
${M g}^{2 +} + {C l}^{-} \leftrightarrow M g {C l}^{+}$	-0,135	Bhuyian, Mavinic e Beckie (2007BHUYIAN, M.I.H.; MAVINIC, D.S.; BECKIE, R.D. (2007) A Solubility and thermodynamic study of struvite. Environmental Technology, v. 28, n. 9, p. 1015-1026. https://doi.org/10.1080/09593332808618857 https://doi.org/10.1080/0959333280861885... )

pK_S0	Condições em KSo foi determinada	Referência
12,76 ± 0,56	Água residuária de suinocultura, [P_solúvel] = 65 mg.L^-1, [N-NH₃] = 1830 mg.L^-1, [Mg] = 170 mg.L^-1, pH entre 6,8 e 8,5, temperatura = 25ºC	Webb e Ho (1991WEBB, K.M.; HO, G.E. (1991) Struvite (MgNH4PO4.6H2O) solubility and its application to a piggery effluent problem. In: WORKSHOP ON APPROPRIATE TECHNOLOGY FOR ENVIRONMENTALLY SUSTAINABLE DEVELOPMENT. Anais… ASEAN, Perth, Australia: Remote Area Developments Group, p. 39-45.)
14	Dissolução de 40 mg de estruvita marcada com o radioisótopo ³²P em 20 mL de água redestilada e soluções diluídas de NaCl 0,030, 0045, 0,06 M, temperatura = 25ºC	*Aage et al. (1997*AAGE, H.K.; ANDERSEN, B.L.; BLOM, A.; JENSEN, I. (1997) The solubility of struvite. Journal of Radioanalytical and Nuclear Chemistry, v. 223, n. 1-2, p. 213-215. https://doi.org/10.1007/BF02223387 https://doi.org/10.1007/BF02223387... )
13,26 ± 0,04	Produção de estruvita em laboratório. Dissolução desta estruvita e de estruvita coletada em sobrenadante de digestor de sistema EBPR em água desionizada tamponada, temperatura = 25 ± 0,5ºC	Ohlinger, Young e Schroeder (1998OHLINGER, K.N.; YOUNG, T.M.; SCHROEDER, E.D. (1998) Predicting struvite formation in digestion. Water Research, v. 32, n. 12, p. 3607-3614. http://dx.doi.org/10.1016/S0043-1354(98)00123-7 http://dx.doi.org/10.1016/S0043-1354(98)... )
13,36 ± 0,28	Água sintética; [Pt] = 310 a 1.860 mg.L^-1; [N-NH₃] = 410 a 1.568 mg.L^-1; [Mg] = 240 a 552 mg.L^-1 = temperatura 25ºC; pH = 7,4; [NaCl] = 0,15 mol.L^-1	Babic-Ivancic et al. (2002BABIC-IVANCIC, V.; KONTREC, J.; KRALJ, D.; BRECEVIC, L. (2002) Precipitation diagrams of struvite and dissolution kinetics of different struvite morphologies. Croatica Chemica Acta, v. 75, n. 1, p. 89-106.)
14,10 ± 0,16	Dissolução de cristais de estruvita em água destilada; pH = 7,01 a 9,52; temperatura de 20ºC	*Rahaman et al.* (2006**RAHAMAN, M.S.; MAVINIC, D.S.; BHUYIAN, M.I.H.; KOCH, F.A. (2006) Exploring the determination of struvite solubility product from analytical results. Environmental Technology, v. 27, n. 9, p. 951-961. https://doi.org/10.1080/09593332708618707 https://doi.org/10.1080/0959333270861870... )
13,55 ± 0,54	Dissolução de cristais de estruvita no sobrenadante do digestor da ETE Annacis Island; pH = 5,62 a 8,77; temperatura de 20ºC
13,53 ± 0,45	Dissolução de cristais de estruvita no sobrenadante do digestor da ETE Lulu Island; pH = 5,89 a 9,02; temperatura de 20ºC
13,45 ± 0,37	Dissolução de cristais de estruvita no sobrenadante do digestor da ETE Penticton; pH = 6,45 a 8,97; temperatura de 20ºC
13,69 ± 0,02	Dissolução de cristais de estruvita em água desionizada contendo solução de NaCl 0,01; 0,02; 0,04 e 0,06 M; pH = 7,4; temperatura de 20ºC	Bhuyian, Mavinic e Beckie (2007BHUYIAN, M.I.H.; MAVINIC, D.S.; BECKIE, R.D. (2007) A Solubility and thermodynamic study of struvite. Environmental Technology, v. 28, n. 9, p. 1015-1026. https://doi.org/10.1080/09593332808618857 https://doi.org/10.1080/0959333280861885... )
13,36 ± 0,07	Dissolução de cristais de estruvita em água desionizada contendo solução de NaCl 0,01; 0,02; 0,04 e 0,06 M; pH = 7,4; temperatura de 25ºC
13,26 ± 0,06	Urina e água sintética; [P-PO₄] = 4,2 a 14,2 mM; [N-NH₄] = 291 a 508 mM; [Mg] = 1,08 a 15,6 mM; [Ca] = 0,7 ± 0,1 mM; temperatura = 25ºC; pH = 9,0; intensidade iônica = 0,32 a 0,56 M	Ronteltap, Maurer e Gujer (2007RONTELTAP, M.; MAURER, M.; GUJER, W. (2007) Struvite precipitation thermodynamics in source-separated urine. Water Research, v. 41, n. 5, p. 977-984. http://dx.doi.org/10.1016/j.watres.2006.11.046 http://dx.doi.org/10.1016/j.watres.2006.... )
11 a 12	Efluente de digestor anaeróbio tratando água residuária de indústria de melaço, [NH₄]=1400 mg.L^-1; [Mg²⁺]=21 mg.L^-1; [] = 24 mg.L^-1; [Ca²⁺] = 21 mg.L^-1; [K⁺] = 2.150 mg.L^-1; sólidos dissolvidos totais = 7.600 mg.L^-1; pH = 7,9, temperatura = 37ºC	Türker e Çelen (2010TÜRKER, M.; ÇELEN, I. (2010) Chemical equilibrium model of struvite precipitation from anaerobic digester effluents. Turkish Journal of Engineering and Environmental Sciences, v. 34, n. 1, p. 39-48. https://doi.org/10.3906/muh-1008-15 https://doi.org/10.3906/muh-1008-15... )
13,17 ± 0,01	Água sintética; [PO₄] = 4 mM; [Mg] = 4 mM e [NH₄] = 4 mM; temperatura = 25ºC; pH = 8,5; 9,0; 9,5 e 10,0; intensidade iônica = 0,0159 M	*Hanhoun et al. (2011*HANHOUN, M.; MONTASTRUC, L.; AZZARO-PANTEL, C.; BISCANS, B.; FRECHE, M.; PIBOULEAU, L. (2011) Temperature impact assessment on struvite solubility product : a thermodynamic modeling approach. Chemical Engineering Journal, v. 167, n. 1, p. 50-58. http://dx.doi.org/10.1016/j.cej.2010.12.001 http://dx.doi.org/10.1016/j.cej.2010.12.... )
14,0	Água sintética; []= 2 mM; [] = 2,2 mM; [Mg²⁺]= 6,0 mM; temperatura 25ºC; pH = 8,5; 3 g.L^-1 de estruvita adicionada	Crutchik e Garrido (2016CRUTCHIK, D.; GARRIDO, J.M. (2016) Kinetics of the reversible reaction of struvite crystallisation. Chemosphere, v. 154, p. 567-572. https://doi.org/10.1016/j.chemosphere.2016.03.134 https://doi.org/10.1016/j.chemosphere.20... )

K_{S o} = (a_{{M g}^{2 +}}) . (a_{{N H}_{4}^{+}}) . (a_{{P O}_{4}^{3 -}}) = \{(γ_{{M g}^{2 +}}) . [{M g}^{2 +}])\} . \{{(γ}_{{N H}_{4}^{+}}) . [{N H}_{4}^{+}]\} . \{{(γ}_{{P O}_{4}^{3 -}}) . [{P O}_{4}^{3 -}]\}

P_{s} = \frac{K_{P S}}{{(α}_{{M g}^{2 +}}) . (α_{{N H}_{4}^{+}}) . (α_{{P O}_{4}^{3 -}})} = \frac{K_{S 0}}{{(α}_{{M g}^{2 +}}) . (γ_{{M g}^{2 +}}) . (α_{{N H}_{4}^{+}}) . (γ_{{N H}_{4}^{+}}) . (α_{{P O}_{4}^{3 -}}) . (γ_{{P O}_{4}^{3 -}})}

S_{a} = \frac{a_{{M g}^{2 +}} . a_{{P O}_{4}^{3 -}} . a_{{N H}_{4}^{+}}}{{(a_{{M g}^{2 +}} . a_{{P O}_{4}^{3 -}} . a_{{N H}_{4}^{+}})}_{e q}} = \frac{I A P}{K_{S 0}}

t_{i n d} = \frac{1}{J} = \frac{1}{Ω} e x p [\frac{β . v^{2} . φ^{3}}{{K_{B}^{3} . T}^{3} . z^{2} . {(l n S_{a})}^{2}}] = \frac{1}{Ω} e x p [\frac{β . v^{2} . φ^{3}}{{(2,3 . K_{B} T)}^{3} . z^{2} . {(l o g S_{a})}^{2}}]

[1] *Autor correspondente: dmmorita@usp.br

Brasil

Brasil

Nucleação na formação de estruvita: estado da arte

Nucleation in the formation of struvite: state of art

RESUMO