Correlation between Iron Reducibility in Natural and Iron-Modified Clays and Its Adsorptive Capability for Arsenic Removal  

作　　者：Irma Lia Botto Simonetta Tuti María Jose Gonzalez Delia Gazzoli Irma Lia Botto;Simonetta Tuti;María Jose Gonzalez;Delia Gazzoli(CEQUINOR (CCT-La Plata-UNLP), La Plata, Argentina;Dipartimento di Scienze, Universitá Roma Tre, Roma, Italy;INREMI (CICPBA-UNLP), La Plata, Argentina;Dipartimento di Chimica, Universitá La Sapienza, Roma, Italy)

机构地区：[1]CEQUINOR (CCT-La Plata-UNLP), La Plata, Argentina [2]Dipartimento di Scienze, Universitá Roma Tre, Roma, Italy [3]INREMI (CICPBA-UNLP), La Plata, Argentina [4]Dipartimento di Chimica, Universitá La Sapienza, Roma, Italy

出　　处：《Advances in Materials Physics and Chemistry》2016年第5期129-139,共11页材料物理与化学进展（英文）

摘　　要：The study reports aspects that allowed to correlate structural and redox properties of iron species deposited on clay minerals with the capacity of geomaterials for arsenic removal. Natural ferruginous clays as well as an iron-poor clay chemically modified with Fe(III) salt (ferrihydrite species) were investigated as adsorbents of the arsenate(V) in water. The study, carried out from minerals from abundant Argentinean deposits, was conducted with the aid of different techniques such as X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM-EDS), Raman Spectroscopy, ICP-AES (Inductively Coupled Plasma) chemical analysis and Temperature Programmed Reduction (TPR). This last technique allowed to detect availability of iron species in oxidic environment with different structural complexity and to determine active sites, accessible for arsenate(V) adsorption. The effect was observed through temperature dependence of the first Fe(III) reduction step (below 570°C) of iron-oxide species. The sequence of reducibility: ferrihydrite > hydrous oxide (goethite) > anhydrous oxide (hematite) > structural iron in clay was in agreement with the availability of iron active sites for the reducing process as well as for the arsenate adsorption. The important role of very high iron content in original samples was also observed. The chemical activation of iron-poor clay by a simple and feasible modification with Fe(III) solutions promoted the deposition of the ferrihydrite active phase with an increase of 2.81% (expressed as Fe2O3) respect to the original content of 1.07%, constituting an accessible and eco-friendly technological alternative to solve the environmental problem of water containing arsenic.The study reports aspects that allowed to correlate structural and redox properties of iron species deposited on clay minerals with the capacity of geomaterials for arsenic removal. Natural ferruginous clays as well as an iron-poor clay chemically modified with Fe(III) salt (ferrihydrite species) were investigated as adsorbents of the arsenate(V) in water. The study, carried out from minerals from abundant Argentinean deposits, was conducted with the aid of different techniques such as X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM-EDS), Raman Spectroscopy, ICP-AES (Inductively Coupled Plasma) chemical analysis and Temperature Programmed Reduction (TPR). This last technique allowed to detect availability of iron species in oxidic environment with different structural complexity and to determine active sites, accessible for arsenate(V) adsorption. The effect was observed through temperature dependence of the first Fe(III) reduction step (below 570°C) of iron-oxide species. The sequence of reducibility: ferrihydrite > hydrous oxide (goethite) > anhydrous oxide (hematite) > structural iron in clay was in agreement with the availability of iron active sites for the reducing process as well as for the arsenate adsorption. The important role of very high iron content in original samples was also observed. The chemical activation of iron-poor clay by a simple and feasible modification with Fe(III) solutions promoted the deposition of the ferrihydrite active phase with an increase of 2.81% (expressed as Fe2O3) respect to the original content of 1.07%, constituting an accessible and eco-friendly technological alternative to solve the environmental problem of water containing arsenic.

关 键 词：Temperature Programmed Reduction Iron-Oxide Species Arsenic Removal 

分 类 号：O64[理学—物理化学]