Removal of 1,4-dioxane by titanium silicalite-1: Separation mechanisms and bioregeneration of sorption sites
| Autor: | Ruihuan Chen, Shaily Mahendra, Yun Liu, Yuanhua Dong, Lan Zhang, Cun Liu, Nicholas W. Johnson, Mengfang Chen |
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| Rok vydání: | 2019 |
| Předmět: |
Aqueous solution
Hydrogen bond Chemistry General Chemical Engineering Sorption 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 6. Clean water Industrial and Manufacturing Engineering 0104 chemical sciences Hydrophobic effect symbols.namesake Molecular dynamics Adsorption Chemical engineering 13. Climate action symbols Environmental Chemistry Solubility van der Waals force 0210 nano-technology |
| Zdroj: | Chemical Engineering Journal. 371:193-202 |
| ISSN: | 1385-8947 |
| Popis: | 1,4-Dioxane is a probable carcinogen and trace contaminant that is difficult to remove from water because of its high solubility and low volatility. Removal of 1,4-dioxane from aqueous solutions by a set of potential adsorbents was investigated using batch experiments that revealed Titanium Silicate-1 (TS-1) as a high-capacity adsorbent (85.17 mg/g) with rapid kinetics (2 min equilibration time). The specific adsorption mechanisms at the molecular level were investigated using multiple approaches including FTIR spectra and molecular dynamics simulation of 1,4-dioxane adsorption on TS-1, which imply that the shape and size of 1,4-dioxane fits tightly into the hydrophobic straight channels of TS-1 with a diameter of 0.56 nm, and thus TS-1 provides strong van der Waals attraction within the channels. Additionally, 1,4-dioxane-water complexation was observed to connect to the frame oxygens of TS-1 via hydrogen bonds inside the channels. The calculated adsorption free energy of 1,4-dioxane was between −24.59 and −27.17 kJ/mol, which was consistent with the value of −24.89 kJ/mol derived from the adsorption isotherms at 298 K. The strong adsorption competition from nonpolar compounds 1,1,1-trichloroethane (TCA) and benzene onto TS-1 further confirmed that the adsorption was attributed to a combined mechanism of host-guest interactions including van der Waals interactions, hydrophobic interactions, and hydrogen bonding. Furthermore, 1,4-dioxane-loaded TS-1 was found to be efficiently regenerated by an enriched bacterial consortium (BD1) with recovery efficiencies for three cycles of 88.2%, 96.47% and nearly 100%, suggesting that TS-1 holds promise as a cost-effective renewable absorbent for eliminating hydrophilic organics from contaminated water supplies. |
| Databáze: | OpenAIRE |
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