Water treatment residuals containing iron and manganese oxides for arsenic removal from water – Characterization of physicochemical properties and adsorption studies
| Autor: | Daniel Ociński, Irena Jacukowicz-Sobala, Elżbieta Kociołek-Balawejder, Jerzy Raczyk, Piotr Mazur |
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| Rok vydání: | 2016 |
| Předmět: |
Sorbent
General Chemical Engineering Inorganic chemistry Arsenate Langmuir adsorption model chemistry.chemical_element 02 engineering and technology General Chemistry 010501 environmental sciences 021001 nanoscience & nanotechnology 01 natural sciences Industrial and Manufacturing Engineering chemistry.chemical_compound symbols.namesake Adsorption chemistry symbols Environmental Chemistry Point of zero charge 0210 nano-technology Arsenic 0105 earth and related environmental sciences BET theory Arsenite |
| Zdroj: | Chemical Engineering Journal. 294:210-221 |
| ISSN: | 1385-8947 |
| DOI: | 10.1016/j.cej.2016.02.111 |
| Popis: | Water treatment residuals (WTRs), generated as a by-product during the deironing and demanganization process of infiltration water, were characterized and examined as arsenate and arsenite sorbent. The raw material consisted mainly of iron and manganese oxides with the ratio of Fe:Mn of 5:1. The adsorbent was also characterized by BET surface area measurement, X-ray diffraction (XRD), SEM EDS microscopy and X-ray photoelectron spectroscopy (XPS). The results showed that WTRs had a high surface area (120 m 2 g −1 ) and were mainly amorphous, with small fractions of crystalline quartz and feroxyhyte. The maximum sorption capacities determined by means of the Langmuir isotherm equation were 132 mg As(III) g −1 and 77 mg As(V) g −1 . The higher arsenite uptake may be attributed to the creation of new adsorption sites at the solid surface as a result of As(III) oxidation. The XPS confirmed that arsenite was oxidized prior to adsorption, which was accompanied by release of Mn 2+ cations followed by their adsorption on the sorbent surface. The effectiveness of arsenate removal decreased with the increase of pH, with a noticeable drop above pH pzc of the sorbent, whereas arsenite adsorption was almost constant at acidic and neutral pH. A slight decrease was observed only above pH = 10 due to repulsion between the negatively charged surface of the sorbent and dissociated arsenites. The kinetic studies revealed that arsenate adsorption on WTRs was mainly controlled by external and intraparticle diffusion, whereas in the case of arsenites the two-step mechanism of the process influenced the rate of As(III) adsorption to a greater degree. The possibility of regeneration of the spent sorbent was also confirmed. |
| Databáze: | OpenAIRE |
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