Arsenic adsorption by innovative iron/calcium in-situ-impregnated mesoporous activated carbons from low-temperature water and effects of the presence of humic acids
| Autor: | Xu-Jin Gong, Yu-Shu Li, Weiguang Li, Yu-Qi Dong |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Environmental Engineering
Iron Health Toxicology and Mutagenesis 0208 environmental biotechnology chemistry.chemical_element 02 engineering and technology 010501 environmental sciences 01 natural sciences Arsenic Water Purification Adsorption Physisorption Desorption medicine Environmental Chemistry Humic acid Humic Substances 0105 earth and related environmental sciences chemistry.chemical_classification Public Health Environmental and Occupational Health General Medicine General Chemistry Pollution 020801 environmental engineering Cold Temperature Kinetics chemistry Chemisorption Charcoal Calcium Mesoporous material Water Pollutants Chemical Activated carbon medicine.drug Nuclear chemistry |
| Zdroj: | Chemosphere. 250:126275 |
| ISSN: | 0045-6535 |
| DOI: | 10.1016/j.chemosphere.2020.126275 |
| Popis: | Innovative iron/calcium in-situ-impregnated mesoporous activated carbons (GL100 and GL200) have been prepared by iron/calcium in-situ-impregnation and Multistage Depth-Activation. Arsenic adsorption kinetics, isotherms, thermodynamics, and re-usability were investigated. Effects of surface-absorbed (ST-HA) and dissolved states humic acid (DHA) on the arsenic adsorption were also determined. Results suggested in-situ iron/calcium impregnation caused the well-development of mesoporous structures during ranges of 2.0–5.0 nm in GL100 and 5.0–50 nm in GL200, respectively. The increase of iron/calcium ensured surface basicity and high ash contents on GL100/GL200, and As(III)/As(V) can be better adsorbed in neutral conditions with higher kinetics in comparison with regular mesoporous carbon XHIT. Maximum adsorption capacities of As(III)/As(V) by GL100 and GL200 were 2.985/3.385 mg/g and 2.516/2.807 mg/g, respectively. Arsenic desorption and carbon re-usability of GL100/200 was improved. As(III)(As (V)) adsorption capacities by GL100 and GL200 were 2.437(1.672) mg/g and 1.740(1.308) mg/g, respectively, after eight cycles. Arsenic adsorption capacities on GL100 were proved to be promoted with the presence of low-level of ST-HA or DHA, and be inhibited at a high-level. As(V) was bound more strongly than As(III) in the presence of ST-HA. As(III)/As(V) uptakes increased slightly and decrease gradually to 1.75/1.86 mg/g in the presence of DHA (0–10 mg DOC/L). Physisorption and chemisorption mechanisms dominant in arsenic adsorption on GL100 in presence of humic acid, forming inner-sphere complexation with metallic oxide, functional groups on carbon surface and humic acid structure, or ternary surface complexation via cationic metal ions as cation bridge. |
| Databáze: | OpenAIRE |
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