Evaluation of low-cost geo-adsorbents for As(V) removal
Four low-cost iron-bearing geo-adsorbents were tested for As(V) removal without pretreatment: Montanit300® (M), diatomite (D), pumice (P) and black sand (BS). The solids were carefully characterized by different analytical techniques (SEM-EDX, TPD-pyridine, N2 Physisorption, XRD and point of zero ch...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2021 |
| País: | España |
| Institución: | Universitat Autònoma de Barcelona |
| Repositorio: | Dipòsit Digital de Documents de la UAB |
| Idioma: | inglés |
| OAI Identifier: | oai:ddd.uab.cat:307063 |
| Acceso en línea: | https://ddd.uab.cat/record/307063 https://dx.doi.org/urn:doi:10.1016/j.eti.2020.101341 |
| Access Level: | acceso abierto |
| Palabra clave: | Adsorption mechanism As(V) removal Fe-bearing minerals Geo-adsorbents |
| Sumario: | Four low-cost iron-bearing geo-adsorbents were tested for As(V) removal without pretreatment: Montanit300® (M), diatomite (D), pumice (P) and black sand (BS). The solids were carefully characterized by different analytical techniques (SEM-EDX, TPD-pyridine, N2 Physisorption, XRD and point of zero charge). The adsorption of As(V) was evaluated through isotherms and kinetic studies (bottled water matrix, pH0=8,25 g/L of solids), and experiments addressing pH effect (pH0=3.6,7.5,11) and the presence of interfering anions (Cl-, SO42-, NO3-, PO43-). Experimental results were fitted to the Freundlich and Langmuir sorption isotherms. Under the employed conditions, P showed negligible adsorption, M and D presented adsorption capacities around 0.02 mg/g and, in spite its lower surface area, BS displayed the highest value (0.045 mg/g), which relates to a higher density of Fe species, M and D samples were easily regenerated (80%-100% desorption) through a basic treatment (0.01 M NaOH) and presented fast adsorption kinetics (1 h for D and seconds for M). BS showed a slow adsorption kinetic (24 h) and poor regeneration (only 50% desorption). Sample M (natural zeolite) resulted a promising option due to its remarkably fast adsorption kinetic, easy regeneration and adsorption capacity suitable for systems with relatively low As concentrations. |
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