Experimental investigations of arsenic adsorption from contaminated water using chemically activated hematite (Fe2O3) iron ore

Removal of arsenate using graphene oxide-iron modified clinoptilolite-based composites: adsorption kinetic and column study

“…The fairly broad absorption peak of GO observed between 3351 and 2956 cm −1 (Fig. 3b) can be attributed to the O-H stretching vibration of the adsorbed water molecules (Sherlala et al 2019;Luo et al 2013). Additionally, the absorption peaks observed at 1718, 1630, 1416, 1180, and 1035 cm −1 in the FTIR spectrum of GO show the C=O, aromatic C=C, C-O group related to carboxyl, C-O group related to epoxy, and C-O group related to alkoxy, respectively (Su et al 2017).…”

“…Although arsenic is found in air, water, many kinds of rock, soil, plant, and living tissues in general, the occurrence of arsenic in groundwater is a great and critical threat around the world (Dhoble et al 2017;Pang et al 2020). Despite the arsenic contamination in the groundwater of many countries in the various parts of the world being generally caused by natural sources such as the erosion of rocks and the dissolutionprecipitation of minerals, some anthropogenic activities such as mining, pharmaceutical industry, and the use of arsenic-containing fertilizers and pesticides in the agriculture also contribute to arsenic pollution (Wu et al 2018;Luo et al 2013;Kundu et al 2004). Groundwater arsenic pollution is a worldwide problem that poses a health risk to millions of people in the countries such as Bangladesh, Vietnam, Indian, Turkey, the USA, and West Africa (Bretzler et al 2020;Yoon et al 2017;Bilici Baskan and Pala 2010).…”

“…Arsenic exists in various forms in the environment, but in the aquatic environment it is mainly found in inorganic form as trivalent arsenite (As(III)) and pentavalent arsenate (As(V)) (Soni and Shukla 2019;Luo et al 2013). Both species are non-biodegradable, highly toxic, and accumulate along the food chain.…”

As(III, V) Uptake from Nanostructured Iron Oxides and Oxyhydroxides: The Complex Interplay between Sorbent Surface Chemistry and Arsenic Equilibria

“…Indeed, the arsenate species should link the iron oxide/oxyhydroxide surface through inner-sphere complexation with oxygen bridges, generating a bidentate binuclear complex for akaganeite and ferrihydrite, and both bidentate binuclear and monodentate mononuclear complex for maghemite [16]. Among the various Fe-based systems, the most employed include the oxides maghemite/magnetite (Fe 3 O 4 /γ-Fe 2 O 3 ) [17][18][19][20], and hematite (α-Fe 2 O 3 ) [21,22], which possess high arsenic adsorbed amount in a wide pH range. Other commonly employed iron compounds are the oxyhydroxides, such as goethite (α-FeOOH) [23], akaganeite (β-FeOOH) [24][25][26][27][28][29][30], schwertmannite [28], and ferrihydrite [23,[31][32][33][34], the latter one being the most studied.…”