The effect of electrolyte anion on Cu adsorption–desorption by clinoptilolite

Doula, M.; Ioannou, A.

doi:10.1016/s1387-1811(02)00610-8

Cited by 76 publications

(50 citation statements)

References 15 publications

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“…Hydrogen cations are released as products and the process causes a total decrease in the solution pH. It is slow and irreversible [8,15].…”

Section: Dissolution Of Framework :½Al-ohmentioning

confidence: 99%

“…Ponizovsky and Tsadilas [7] showed that ion exchange was the only possible mechanism for the lead retention on clinoptilolite rich natural zeolitic material in various pH values. Doula and Ioannou [8] investigated the effects of electrolyte anion on Cu adsorption-desorption by clinoptilolite rich natural zeolitic material. Three different electrolytes KCl, KNO 3 , and K 2 SO 4 were used for desorption.…”

Section: Introductionmentioning

confidence: 99%

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Aqueous interactions of zeolitic material in acidic and basic solutions

Polatoğlu

Çakıcıoğlu-Özkan

2010

Microporous and Mesoporous Materials

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a b s t r a c tAqueous interactions of natural zeolitic material in as-received and modified forms were studied. The zeolitic materials was interacted with acidic (hydrochloric acid, lactic acid, acetic acid) and basic (sodium hydroxide) solutions. Ion exchange, adsorption, complex formation, precipitation and cation hydrolysis were possible interaction mechanisms affected by the amount and cation content of zeolite and pH. The dominant mechanisms seemed to be ion exchange and adsorption in HCl solution when zeolite was used in the as-received form, but dissociation of outer-sphere complexes when modified zeolite was used. In lactic acid, acetic acid as well as the basic solution, cation hydrolysis and complex formation were additional mechanism in the interactions.

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“…Hydrogen cations are released as products and the process causes a total decrease in the solution pH. It is slow and irreversible [8,15].…”

Section: Dissolution Of Framework :½Al-ohmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Aqueous interactions of zeolitic material in acidic and basic solutions

Polatoğlu

Çakıcıoğlu-Özkan

2010

Microporous and Mesoporous Materials

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“…The adsorption of Cl À , especially specific adsorption of Cl À onto variable charge soils (Wang et al 1987), adding negative charges to variable charge surfaces, might be another possibility of the Cl À effect on the Cu 2+ adsorption-desorption (Doula and Ioannou 2003). Chloride adsorption occurred during the Cu adsorption by clinoptilolite in the 0.01 mol KNO 3 L À1 electrolyte, in which the Cu source was CuCl 2 , but Cl À adsorption was lower in the 0.01 mol KCl L À1 electrolyte than in the 0.01 mol KNO 3 L À1 electrolyte (Doula and Ioannou 2003). This was evidenced by the higher residual Cu 2+ in the soils treated with higher initial Cu 2+ concentrations (>10 mg L À1 for TTD soil and >20 mg L À1 for KTP soil) in the presence of Cl À after successive extractions with 1 mol NH 4 OAc L À1 (pH 5.0) ( Table 6).…”

Section: Anionsmentioning

confidence: 99%

Effects of Anions on the Capacity and Affinity of Copper Adsorption in Two Variable Charge Soils

Huang

et al. 2005

Biogeochemistry

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Effects of nitrate ðNO À 3 Þ, chloride (Cl À ), sulfate ðSO 2À 4 Þ, and acetate (Ac À ) on Cu 2+ adsorption and affinity of the adsorbed Cu 2+ were evaluated in two Fe and Al enriched variable charge soils from Southern China. The maximum adsorption of Cu 2+ (M, a parameter from the Langmuir isotherm model) in the presence of different anions decreased in the order Cl À > Ac À > NO À 3 > SO 2À 4 for both soils. The clayey loamy soil (mixed siliceous thermic Typic Dystrochrept, TTD), developed on the Arenaceous rock, adsorbed less Cu 2+ than the clayey soil (kaolinitic thermic Plinthudults, KTP), derived from the Quaternary red earths, regardless of anion type present in the medium. The affinity of adsorbed Cu 2+ to both soils could be characterized by the Kd (distribution coefficient) values and successive extraction of the adsorbed Cu 2+ with 1-mol NH 4 Ac L À1 . The log 10 Kd value was smaller for the TTD soil than for the KTP soil and decreased in the order of Cl À > NO À 3 > SO 2À 4 > Ac À at low initial Cu 2+ concentrations ( £ 40 mg Cu 2+ L À1 ), whereas at 80 mg Cu 2+ L À1 , the log 10 Kd value was similar for NO À 3 , SO 2À 4 , and Ac À , but was slightly higher for Cl À . Complete extraction of Cu 2+ adsorbed in the presence of Ac À was achieved. Influence of NO À 3 and SO 2À 4 on the affinity of adsorbed Cu 2+ was similar, but the effects of Cl À depended on the initial Cu 2+ concentrations. The extracted percentage of the adsorbed Cu 2+ in the presence of NO À 3 or SO 2À 4 increased with increasing Cu 2+ adsorption saturation. The presence of Cl À , NO À 3 , or SO 2À 4 markedly decreased the equilibrium solution pH for both soils with increasing initial Cu 2+ concentrations, and the delta pH values at the highest Cu 2+ level were 0.5, 0.63, and 0.55 U for the TTD soil and 0.79, 0.84, and 0.93 U for the KTP soil, respectively for the three anions. The presence of Ac À had a minimal influence on the equilibrium solution pH because of the buffering nature of the NaAc/HAc medium which buffered the released protons. The effects of anions on Cu 2+ adsorption and affinity of the adsorbed Cu 2+ were dependent on anion types and were apparently related to the altered surface properties caused by anion adsorption and/or the formation of anion-Cu 2+ complexes.Abbreviations: AAS -atomic absorption spectrometry; Ac À -acetate; CEC -cation exchange capacity at pH 7.0; Cl À -chloride; Freundlich equation -q ¼ k F C n , where q is the amount of adsorbed Cu 2+ , k F is a constant related to total adsorption capacity of the soils.; Kd -distribution coefficient; KTP soil -a soil of kaolinitic thermic Plinthudults; Langmuir equation -q ¼ (k L MC)/(l+k L C), where q is the amount of adsorbed Cu 2+ , M is the maximum adsorption of Cu 2+ , and k L is a constant related to binding energy; NaAc/HAc medium -a buffering medium consisting of sodium acetate and acetic acid; NH 4 Acammonium acetate; NO À 3 -nitrate; rcf -rotational centrifugal force; SO 2À 4 -sulfate; TTD soil -a soil of mixed siliceous thermic typic Dystrochrept B...

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“…Generally, industrial wastewaters contain not only heavy metal ions but also high concentrations of organic and inorganic substances. Inorganic electrolyte anions, such as chloride (Cl À ), nitrate ( ), are commonly present in natural water and wastewater systems (Zhu et al, 2007), and these anions can affect metal cations adsorption directly or indirectly (Doula and Ioannou, 2003). Thus, investigation of the influence of inorganic electrolyte anions on heavy metals adsorption is essential to evaluate the adsorption capacity of an adsorbent and apply the laboratory results to practical projects.…”

Section: Introductionmentioning

confidence: 99%