Specific ion effect on the point of zero charge of α-alumina and on the adsorption of 3,4-dihydroxybenzoic acid onto α-alumina surface

Sarma, Jyotirmoy; Mahiuddin, Sekh

doi:10.1016/j.colsurfa.2014.06.014

Cited by 35 publications

(14 citation statements)

References 52 publications

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“…The point of zero charge (PZC) for ACLP was investigated by the solid addition method (Sarma and Mahiuddin, 2014). A suspension of 0.1 g ACLP in 45 ml 0.1 M NaCl was equilibrated at 25 о C ± 2 on an orbital shaker (Protech Model 722) for 24 h.…”

Section: Point Of Zero Charge (Pzc)mentioning

confidence: 99%

Characterization and optimization of effluent dye removal using a new low cost adsorbent: Equilibrium, kinetics and thermodynamic study

Ezechi

Kutty

Malakahmad

et al. 2015

Process Safety and Environmental Protection

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Section: Point Of Zero Charge (Pzc)mentioning

confidence: 99%

Characterization and optimization of effluent dye removal using a new low cost adsorbent: Equilibrium, kinetics and thermodynamic study

Ezechi

Kutty

Malakahmad

et al. 2015

Process Safety and Environmental Protection

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“…O pHPCZ é o valor de pH em que as concentrações negativas e positivas da superfície são iguais, ou seja, a carga da superfície é zero [16]. Por ser um fator de grande influência na adsorção de metais, juntamente com o pH da solução, permite prever se a carga será positiva para pH < pHPCZ ou negativa para pH > pHPCZ [17].…”

Section: Introductionunclassified

Identificação dos mecanismos de sorção em zeólita NaY e sílica gel

et al. 2017

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RESUMOO estudo do mecanismo de sorção e da influência do pH inicial da solução em materiais sólidos se faz necessário, pois o simples fato de alterar o valor de pH da solução pode alterar a capacidade de sorção de um adsorvato. Foi avaliada a sorção dos íons Ca 2+ e Mg 2+ em três valores de pH dependendo do ponto de carga zero (pHPCZ) em zeólita NaY ou sílica gel (pH < pHPCZ; pH = pHPCZ; pH > pHPCZ). Foi obtida a cinética de sorção e ajustados os modelos de pseudo-primeira ordem, pseudo-segunda ordem e difusão intrapartícula dos íons nos dois materiais de estudo. Na zeólita NaY o valor de pH que obteve maior capacidade de sorção foi o 4,3 (pH < pHPCZ) e o modelo de pseudo-segunda ordem obteve um melhor ajuste aos dados experimentais. Neste material a quantidade adsorvida é pequena quando comparada à troca iônica. Enquanto, na sílica gel a maior capacidade de sorção se deu no valor de pH de 6,7 (pH > pHPCZ) e o modelo que melhor se ajustou aos dados experimentais também foi o de pseudo-segunda ordem, concluindo-se que a adsorção é o principal mecanismo de sorção. Palavras-chave:Mecanismo de sorção; Sílica gel; Zeólita NaY; Ponto de carga zero. ABSTRACTThe study of the sorption mechanism and the initial pH of the solution influence in solid materials is necessary, because the simple fact of changing the pH of the solution can modify the sorption capacity of an adsorbate. It was evaluated the sorption of ions Ca 2+ and Mg 2+ at three pH values depending on the point of zero charge (pHPZC) on NaY zeolite or silica gel (pH < pHPZC; pH = pHPZC; pH > pHPZC). The sorption kinetics was obtained and adjusted by models of pseudo-first-order, pseudo-second-order and intraparticle diffusion of ions in the two studyied materials. In NaY zeolite adsorbent, the pH value had a higher sorption capacity was 4.3 (pH < pHPZC) and pseudo-second-order model showed a better fit to the experimental data. In this material the adsorbed amount is small when compared to ion exchange. While in the silica gel, the highest sorption capacity occurred at pH 6.7 (pH > pHPZC) and the model that best fit the data experimental was also the pseudo-second-order, concluding that the adsorption is main sorption mechanism.Keywords: Sorption mechanism; Silica gel; NaY zeolite; Point of zero chance. INTRODUÇÃOO aumento da população mundial e o desenvolvimento econômico introduziu uma enorme quantidade de contaminantes, como os íons metálicos [1]. A não remoção de metais de efluentes pode causar danos tanto à saúde humana quanto à indústria, pois metais como cálcio e magnésio são associados à dureza da água [2]. Para a remoção desses metais presentes nos efluentes, são utilizados diversos processos, como a precipitação química, coagulação, floculação, evaporação, decantação e processos com membrana [3]. Entretanto, em geral, estes processos apresentam alto custo operacional e/ou baixa eficiência no caso de baixas concentrações de metais dissolvidas nos efluentes [4,5,6,7]. Neste contexto, os processos de adsorção/troca iônica vêm se constituindo em alternat...

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“…The essays were replicated four times for each sample and the average data are reported. The point of cero charge (PZC) of Z-N and Z-Al was determined by the pH drift method [21,22]. An amount 0.1 g of zeolite was equilibrated in 25 mL of deionized water and 0.01 and 0.05 M NaCl solutions (pH from 2 to 11) for 24 hours at 200 rpm and 21±1 °C.…”

Section: Physicochemical Characterization Of the Zeolitesmentioning

confidence: 99%

Simultaneous phosphate and ammonium removal from aqueous solution by a hydrated aluminum oxide modified natural zeolite

Guaya

Valderrama

Farrán

et al. 2015

Chemical Engineering Journal

257

106

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A natural zeolite (Z-N), rich in clinoptilolite, was modified (Z-Al) by incorporation of hydrated aluminum oxide (HAlO) for the simultaneous phosphate and ammonium removal. The incorporation of surface hydroxyl groups (≅Al-OH) into the zeolite structure, as active groups for phosphate removal, was characterized by acid-base titrations (pHPZC=4.5±0.2). The phosphate sorption increases from 0.6 mg-P/g for Z-N up to 7.0 mg-P/g while only a slight decrease on the ammonium sorption capacity from 33 mg-N/g of Z-N to 30 mg-N/g for Z-Al was observed. The HAlO modified zeolite sorption capacity for both phosphate and ammonium was slightly reduced by common ions typically present in secondary waste water effluents. Column experiments revealed higher enrichment factor for ammonium (120) than for phosphate (50) using 1 M NaOH as elution solution. A reduction of zeolite phosphate capacity with regeneration cycles was observed.

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Specific ion effect on the point of zero charge of α-alumina and on the adsorption of 3,4-dihydroxybenzoic acid onto α-alumina surface

Cited by 35 publications

References 52 publications

Characterization and optimization of effluent dye removal using a new low cost adsorbent: Equilibrium, kinetics and thermodynamic study

Characterization and optimization of effluent dye removal using a new low cost adsorbent: Equilibrium, kinetics and thermodynamic study

Identificação dos mecanismos de sorção em zeólita NaY e sílica gel

Simultaneous phosphate and ammonium removal from aqueous solution by a hydrated aluminum oxide modified natural zeolite

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