Interaction of inorganic anions with iron-mineral adsorbents in aqueous media--a review.
A number of inorganic anions (e.g., nitrate, fluoride, bromate, phosphate, and perchlorate) have been reported in alarming concentrations in numerous drinking water sources around the world. Their presence even in very low concentrations may cause serious environmental and health related problems. Due to the presence and significance of iron minerals in the natural aquatic environment and increasing application of iron in water treatment, the knowledge of the structure of iron and iron minerals and their interactions with aquatic pollutants, especially inorganic anions in water are of great importance. Iron minerals have been known since long as potential adsorbents for the removal of inorganic anions from aqueous phase. The chemistry of iron and iron minerals reactions in water is complex. The adsorption ability of iron and iron minerals towards inorganic anions is influenced by several factors such as, surface characteristics of the adsorbent (surface area, density, pore volume, porosity, pore size distribution, pHpzc, purity), pH of the solution, and ionic strength. Furthermore, the physico-chemical properties of inorganic anions (pore size, ionic radius, bulk diffusion coefficient) also significantly influence the adsorption process. The aim of this paper is to provide an overview of the properties of iron and iron minerals and their reactivity with some important inorganic anionic contaminants present in water. It also summarizes the usage of iron and iron minerals in water treatment technology.
Department of Biology and Environmental Science, Faculty of Health and Life Sciences, Linnaeus University, SE-391 82 Kalmar, Sweden.
Eva
E
Kumar
Department of Biology and Environmental Science, Faculty of Health and Life Sciences, Linnaeus University, SE-391 82 Kalmar, Sweden. Electronic address: amit.bhatnagar@lnu.se.
Amit
A
Bhatnagar
Department of Biology and Environmental Science, Faculty of Health and Life Sciences, Linnaeus University, SE-391 82 Kalmar, Sweden.
William
W
Hogland
Department of Biology and Environmental Science, Faculty of Health and Life Sciences, Linnaeus University, SE-391 82 Kalmar, Sweden; Department of Sanitary and Environmental Engineering, Rio de Janeiro State University, UERJ, Rio de Janeiro, Brazil.
Marcia
M
Marques
Laboratory of Green Chemistry, Faculty of Technology, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli, Finland.
Mika
M
Sillanpää
D000327:Adsorption; D007501:Iron / Q000737:chemistry*; D008903:Minerals / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
D008903:Minerals; D014874:Water Pollutants, Chemical; D014867:Water; D007501:Iron
Adsorption; Adsorption mechanism; Inorganic anionic pollutants; Iron minerals; Review