Cation diffusion in the natural zeolite clinoptilolite

Dyer, A.; White, Kevin J.

doi:10.1016/s0040-6031(99)00280-4

Cited by 39 publications

(21 citation statements)

References 14 publications

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“…In these studies U (t) was generally lower than 0.7. The exact solutions for infinite and finite volume conditions for isotopic exchange are shown to be in good agreement in the case of various binary cation exchange on clinoptilolite (23). In all cases the value for w was about 0.30.…”

Section: Isotopic Exchangementioning

confidence: 70%

Applicability of Simplified Models for the Estimation of Ion Exchange Diffusion Coefficients in Zeolites

Inglezakis

Grigoropoulou

2001

Journal of Colloid and Interface Science

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Section: Isotopic Exchangementioning

confidence: 70%

Applicability of Simplified Models for the Estimation of Ion Exchange Diffusion Coefficients in Zeolites

Inglezakis

Grigoropoulou

2001

Journal of Colloid and Interface Science

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“…They concluded that the exchange rate is controlled by the film diffusion at the start of the reaction and by the particle-internal diffusion in the rest time. Dyer et al (1999) investigated the ion-exchange processes in clinoptilolite involving the NH + 4 , Na + , K + , Ca 2+ , and Mg 2+ cations, and they proposed that the rate determining step may be the movement of ingoing or outgoing cations through the clinoptilolite intraparticle pore, but they did not investigate the NH + 4 -K + ion-exchange process in detail. In this work the control mechanism, the mass transfer model, the kinetic curves and the mass transfer coefficients of NH + 4 -K + ion exchange on K-clinoptilolite are studied in order to provide the help for further studies on the recovery of potassium from brine and the disposal of industrial sewages using zeolite.…”

Section: Introductionmentioning

confidence: 99%

Transfer model and kinetic characteristics of $${\rm NH}_{4}^{+}$$ –K+ ion exchange on K-zeolite

2007

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Based on the mass transfer theory, a new mass transfer model of ion-exchange process on zeolite under liquid film diffusion control is established, and the kinetic curves and the mass transfer coefficients of NH + 4 -K + ion-exchange under different conditions were systemically determined using the shallow-bed experimental method. The results showed that the NH + 4 -K + ion-exchange rates and transfer coefficients are directly proportional to solution flow rate and temperature, and inversely proportional to solution viscosity and the size of zeolite granules. It also showed that the transfer coefficient is not influenced by the ion concentrations. For a large ranges of operational conditions including temperatures (10−75 • C), flow rates (0.031 m s −1 −0.26 m s −1 ), liquid viscosities (1.002×10 −3 N s m −2 − 4.44 × 10 −3 N s m −2 ), and zeolite granular sizes (0.2 − 1.45 mm), the average mass transfer coefficients calculated by the model agree with the experimental results very well.Keywords K-zeolite · Ammonium · Ion exchange · Kinetics · Mass transfer mechanism · Mass transfer model Nomenclature A C Concentration of ion A in zeolite, dimensionless A S Concentration of ion A in solution, dimensionless a Interfacial area per granule volume, m 2 m −3 C A Concentration of ion A in solution, mol L −1 C A0 Primal concentration of ion A in solution, mol L −1 C A * Equilibrium concentration of ion A on zeolite, mol L −1 D A Diffusion coefficient of ion A, m 2 s −1 F Exchange rate of ion A in zeolite, F = q/Q, % 123 72 Y. Junsheng et al. K fx Mass transfer coefficient, m s −1 K f Average mass transfer coefficient, m s −1 L Size of zeolite granule, m n A Mass transfer rate of ion A, kg m −2 s −1 q NH + 4 concentration in zeolite, kg (kg zeolite) −1 Q NH + 4 saturated exchange capacities of zeolite, kg (kg zeolite) −1 Re x Local Reynolds number, Re x = ρu • x/µ, dimensionless Sc Schmidt number, Sc = µ/(ρD A ), dimensionless T Temperature, • C t Time, s U Flow rate of liquid, m s −1 u 0 Main flow rate of liquid, m s −1 u x Flow rate of liquid in film, m s −1 V Volume of liquid, m 3 V 1 Volume of liquid at certain time, m 3 v Flux of liquid, m 3 s −1 w Weight of zeolite, kg δ Motion boundary layer thickness, m δ D Concentration boundary layer thickness , m ε Interspace Ratio of zeolite layer, dimensionless µ Viscosity of liquid, N s m −2 γ Dynamic viscosity of liquid, m 2 s −1 ρDensity of liquid, kg m −3 ρ A Mass concentration of ion A in solution, kg m −3 ρ A Average mass concentration of ion A in solution, kg m −3 ρ A0 Primal mass concentration of ion A in solution, kg m −3 ρ A * Equilibrium mass concentration of ion A on zeolite, kg m −3 ρ s Density of zeolite, kg m −3

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“…11 Apesar de sua capacidade de troca ser inferior à de outras zeólitas naturais e sintéticas, 14,23 sua alta seletividade para o íon NH 4 + vem atraindo a atenção para seu emprego (desde a década de 70) no tratamento de efluentes, 13,23,24 inclusive sob baixas temperaturas, 24 e até mesmo na remediação de solos. 19 Dependendo da origem da clinoptilolita, ela terá uma capacidade de retenção diferente para o íon NH 4 + , em função da presença de impurezas (especialmente, quartzo) 14 e outros elementos que a acompanham. Mesmo assim, pesquisas mostram que a remoção do íon NH 4 + no tratamento de água potável e de esgoto urbano pode ter eficiência superior a 97% m/m.…”

Section: Métodos De Remoção Do íOn Nh 4 +unclassified

Remoção do íon amônio de águas produzidas na exploração de petróleo em áreas offshore por adsorção em clinoptilolita

Lima¹,

Wildhagen²,

Cunha³

et al. 2008

Quím. Nova

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Recebido em 12/6/07; aceito em 30/8/07; publicado na web em 2/4/08 REMOVAL OF AMMONIUM IONS FROM WATERS PRODUCED IN PETROLEUM OFFSHORE EXPLOITATION BY ADSORPTION ON CLINOPTILOLITE:This work describes the use of clinoptilolite for removal of ammonium ions present in waters produced at the Campos' Basin. Samples were previously treated in order to remove organic compounds and metals. Experiments were run in fixed-and fluidized-bed systems, at room temperature. The fluidized-bed systems did not remove efficiently the ammonium ion. The best operational conditions were obtained with clinoptilolite particle size in the range 0.30-0.50 mm, under ascendant flow (3 mL min -1 ), in a fixed-bed system. The best zeolite performance was found when it was pretreated with 0.5 mol L -1 NaOH. Na + was the most important interfering ion due to its high concentration in the water. Clinoptilolite lost partially its capacity to retain ammonium ions after several regeneration cycles with NaOH.Keywords: ammonium ion; produced water; clinoptilolite. INTRODUÇÃO A água produzida na exploração de petróleoAo longo da exploração de petróleo de jazidas em terra (onshore) ou no mar (offshore), existe geração concomitante de um efluente aquoso, denominado água produzida, que representa a maior corrente de resíduo na produção do óleo cru.Para manter as condições de pressão na rocha-reservatório, condição para a migração do petróleo para os poços, principalmente em áreas offshore, normalmente é efetuada uma operação de injeção de água nas camadas inferiores do reservatório. A participação da água produzida no óleo associado varia durante a produção do petróleo. Um campo novo produz de 5 a 15% de volume de água. À medida que a vida econômica dos poços se esgota, essa água pode atingir uma faixa de 75 a 90% vol.. [1][2][3][4] A produção excessiva de água é um problema sério nos campos de petróleo maduros, isto é, aqueles que têm permanecido em operação por longo período de tempo. A eficiência do separador água/óleo diminui. Depois do separador, a água contendo óleo (gotas microemulsionadas), produtos químicos dissolvidos e até microorganismos precisa ser tratada. 5 Em áreas offshore o descarte é feito em grandes ambientes receptores, onde a diluição e a dispersão rápida tomam lugar. Isto poderia ser uma argumentação para o não tratamento da água produzida. Mas fatores, tais como correntes marítimas, ventos, temperatura da água, mudança de clima, podem transportar ou mesmo concentrar alguns de seus constituintes (fenóis, íon NH 4 + etc.). O descarte de tais volumes de resíduos vem causando preocupações sobre a poluição ambiental não controlada e irreversível no ambiente marinho. As águas produzidas apresentam, em geral, altos teores de contaminantes tóxicos (metais pesados, tais como Cd, Cr, Cu, Pb, Hg, Ag, Ni, Zn; produtos químicos adicionados durante a injeção, tais como inibidores de corrosão, inibidores de incrustação, desemulsificantes, metanol, glicol, polieletrólitos), além de uma complexa mistura de compostos orgânicos e inorgânicos, cuja c...

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Cation diffusion in the natural zeolite clinoptilolite

Cited by 39 publications

References 14 publications

Applicability of Simplified Models for the Estimation of Ion Exchange Diffusion Coefficients in Zeolites

Applicability of Simplified Models for the Estimation of Ion Exchange Diffusion Coefficients in Zeolites

Transfer model and kinetic characteristics of $${\rm NH}_{4}^{+}$$ –K+ ion exchange on K-zeolite

Remoção do íon amônio de águas produzidas na exploração de petróleo em áreas offshore por adsorção em clinoptilolita

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