The iron(III)-modified natural zeolitic tuff as an adsorbent and carrier for selenium oxyanions

• Published in: Microporous and mesoporous materials 2014-10, Vol.197, p.92-100
• Main Authors: Jevtić, Sanja, Arčon, Iztok, Rečnik, Aleksander, Babić, Biljana, Mazaj, Matjaž, Pavlović, Jelena, Matijaševic, Danka, Nikšić, Miomir, Rajić, Nevenka
• Format: Article
• Language: English
• Subjects: Chemistry; Clinoptilolite; Colloidal state and disperse state; Exact sciences and technology; EXAFS; General and physical chemistry; Ion-exchange; Mushroom; Porous materials; Selenium; Surface physical chemistry; TEM; Zeolites: preparations and properties
• ISSN: 1387-1811; 1873-3093
• DOI: 10.1016/j.micromeso.2014.06.008

Pleurotus ostreatus cultivated on: (a) SeIV-CLI enriched substrate (right) and control sample (left) and (b) SeVI-CLI enriched substrate (right) and control sample (left). •Iron(III)-modified zeolitic tuff efficiently adsorbs selenium oxyanions.•Se is bound in the form of oxo-complexes to Fe(III) at the clinoptilolite surface.•Se-loaded zeolitic tuff is good supplement for cultivation of Pleurotus ostreatus.•Fungus transform inorganic Se into organically bound form. Se(IV) and Se(VI) anions are the dominant species of Se existing in aqueous systems. In this study, the iron(III)-modified natural zeolitic tuff (Fe-CLI) from the Serbian deposit Zlatokop has been investigated as an adsorbent for the Se oxyanions. Fe-CLI shows adsorption activity for both Se(IV) and Se(VI) which decreases with increasing pH. The adsorption capacity of Fe-CLI is found to be higher for Se(IV) than for Se(VI). Kinetics data follow the pseudo-second-order model and the obtained parameters k indicate that the rates of adsorption and desorption are higher for Se(VI). Extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) analyses reveal that Se is bound at the zeolite surface forming not only the Se–O–Fe but also Se–O–Si bonds. The adsorption mechanism depends of the type of oxo ions. Samples of zeolitic tuff which contain Se were tested as soil supplements for the cultivation of Pleurotus ostreatus mushrooms. The fungus adsorbed the inorganic Se from zeolitic tuff transforming it to a more valuable organically bound form.