Adsorption of heavy metals in acid to alkaline environments by montmorillonite and Ca-montmorillonite
| Autor: | Mohamed Abatal, Liberto de Pablo, M. Lourdes Chávez |
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| Rok vydání: | 2011 |
| Předmět: |
General Chemical Engineering
Kinetics Inorganic chemistry Cationic polymerization Langmuir adsorption model Heavy metals General Chemistry Industrial and Manufacturing Engineering chemistry.chemical_compound symbols.namesake Adsorption Montmorillonite chemistry symbols Environmental Chemistry Qualitative inorganic analysis Selectivity |
| Zdroj: | Chemical Engineering Journal. 171:1276-1286 |
| ISSN: | 1385-8947 |
| DOI: | 10.1016/j.cej.2011.05.055 |
| Popis: | Adsorption of Hg 2+ , Cr 3+ , Pb 2+ , Cu 2+ , Zn 2+ , Ba 2+ , Ni 2+ , Mn 2+ , Cd 2+ , Ba 2+ and Ag + by Ca-montmorillonite from monocationic solutions followed second-order kinetics, attaining removals q e of Pb 2+ 6.187 × 10 2 , Hg 2+ 4.369 × 10 2 , Cu 2+ 2.045 × 10 2 , Zn 2+ 1.576 × 10 2 , Ag + 1.375 × 10 2 , Cr 3+ 7.917 × 10 1 , Ni 2+ 7.300 × 10 1 , Ba 2+ 6.815 × 10 1 , Cd 2+ 2.003 × 10 1 and Mn 2+ 1.632 × 10 1 mg g −1 , greater than those by montmorillonite. Equilibrium adsorption by montmorillonite from bimodal metal + Ca 2+ solutions followed the Langmuir model with adsorptions of Zn 2+ 3.477 × 10 1 , Ba 2+ 6.984, Hg 2+ 3.681 × 10 1 , Ni 2+ 4.849, Mn 2+ 3.820 and Cd 2+ 6.978 mg g −1 , and by Ca-montmorillonite of Zn 2+ 3.523 × 10 1 , Ba 2+ 1.073 × 10 1 and Ni 2+ 5.969 mg g −1 . Within the pH range established by acid cationic solutions and near neutral montmorillonite and Ca-montmorillonite, at pHs below 5 precipitate oxides and hydroxides of Cr 3+ , Pb 2+ and Cu 2+ while at higher pHs Hg 2 2+ , Zn 2+ , Ba 2+ , Cd 2+ , Ni 2+ , Mn 2+ and Ag + remain in solution and are adsorbed as simple and hydroxyl cations by the clay, keeping the selectivity sequence Hg 2 2+ > Zn 2+ > Ba 2+ > Cd 2+ > Ni 2+ > Mn 2+ . |
| Databáze: | OpenAIRE |
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