Removing organic contaminants with bifunctional iron modified rectorite as efficient adsorbent and visible light photo-Fenton catalyst

摘要

Iron-modified rectorite (FeR) was prepared as both adsorbent and catalyst. The iron modification increased layer-to-layer spacing and surface area of rectorite, leading to much increased adsorption of Rhodamine B (RhB) on rectorite. The maximum adsorption capacity of RhB on FeR reached 101 mgg"1 at pH 4.5, being 11 folds of that on the unmodified one. The iron modification also enabled rectorite to have efficient visible light photocatalytic ability. The apparent rate constant for the degradation of RhB (80μM) at 298 K and pH 4.5 in the presence of H_2O_3 (6.0mM) and FeR (0.4gL~(-1)) was evaluated to be 0.0413 min~(-1) under visible light and 0.122 min~(-1) under sunlight, respectively. The analysis with electron spin resonance spin-trapping technique supported that the iron modified rectorite effectively catalyzed the decomposition of H_2O_2 into hydroxyl radicals. On the basis of the characterization and analysis, the new bifunctional material was well clarified as both adsorbent and photocatalyst in the removing of organic pollutants.