As(III) adsorption on Fe-Mn binary oxides: Are Fe and Mn oxides synergistic or antagonistic for arsenic removal?

Abstract

Fe-Mn binary oxides are ubiquitous in the natural environment and have attracted increasing interest due to their high removal capacity for As(III), as well as their important role in the natural cycling of arsenic. Although numerous studies have characterized the respective roles of Fe and Mn oxides in As(III) removal, the relationship between different Fe-Mn binary oxides for As(III) removal has not been fully explored. In this study, three Fe-Mn binary oxides containing either ferrihydrite, hematite or goethite, were used to evaluate their adsorption capacities for As(III) in comparison with their corresponding single Fe and Mn oxide forms. We utilized spectroscopic techniques of in situ flow ATR-FTIR and XPS combined with a Donnan reactor, where Fe and Mn oxides were isolated by a semipermeable membrane through which arsenic could pass, to investigate the dynamics and speciation transformation of As(III) within mixed Fe and Mn oxides systems. The result showed that the synergistic effect, as well as antagonistic effects, between Fe and Mn oxides, was present in Fe-Mn binary oxides for As(III) removal. An obvious increase in As(III) removal with hematite, containing Fe-Mn binary oxides, and a decrease in ferrihydrite, containing Fe-Mn binary oxides, was attributed to As(III) oxidation mediated by Mn oxides as well as the difference in arsenic adsorption affinity in Fe oxides, evidenced by ATR-FTI R and XPS analyses. The findings of this work provide a new understanding of the fate of arsenic within mixed systems, which is very important for targeted application of Fe-Mn binary oxides in treating real arsenic contaminated groundwater.

Removal and Oxidation of As(III) from Water Using Iron Oxide Coated CTAB as Adsorbent

“…Considering the experimental conditions and the adsorption process parameters such as pH solution, sorbent mass, initial concentration of pollutant material, and the experiment duration, the adsorption capacity of As(III) ions by iron oxide or iron oxide composites was reported between 8 and 66.53 mg/g [ 11 , 45 , 46 ]. Nonetheless, during the years, extensive research has been conducted with the sole purpose of improving the properties of adsorbents [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. Moreover, in their recent studies, Otero-González et al [ 13 ] reported that the estimated maximum adsorption values (q max ) values obtained in the case of As(III) retention on novel nanostructured iron oxide cryogels were 625 and 588 mg As(III) per g of Fe for the IO gel and the IO/AAm/MBAA cryogel, respectively.…”

“…The adsorption isotherms for the arsenic removal by IO-CTAB nanoparticles were obtained by mixing solutions containing different concentrations of As(III) with 0.2 g of IO-CTAB nanoparticles until thermodynamic equilibrium at ambient temperature (T = 25 • C) was achieved. Previously reported studies emphasized that the thermodynamic equilibrium at ambient temperature can be achieved in less than 24 h [13][14][15][16][17][18][19][20][21].…”

“…In water treatment technologies, adsorption processes are usually involved, and the materials used as adsorbents should possess specific features such as small-sized particles and a large specific surface area. Iron oxide nanoparticles with a highly specific surface area have been investigated as low-cost adsorbents with a high adsorption capacity for metal ions, which could also be conveniently recovered by magnetic separation after the decontamination process [10][11][12][13][14][15][16][17][18][19][20][21]. Therefore, this study focused on the development of iron oxide nanoparticles coated with cetyltrimethylammonium bromide (CTAB) nanoparticles for environmental applications.…”

“…Research made in the material sciences for environmental applications related to the synthesis and modification of nanoparticles (NPs) has had a great impact on material engineering and surface science applications due to the unique chemical and physical properties of materials at a nanometric scale compared to bulk materials. In recent years, the interest in the efficient synthesis of magnetic iron oxide nanoparticles and their functionalization has increased considerably due to their wide range in various applications as well as their applications for metal ion removal from aqueous solutions [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. Previous studies have reported that different iron oxide species such as Fe 3 O 4 , α-Fe 2 O 3 , and ɤ-Fe 2 O 3 that interact with As had the ability to remove both As(III) and As(V) from water [ 15 , 19 ].…”

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

“…Among these methods, adsorption has attracted more attention due to its ease of operation, low cost, sustainability, efficiency, low waste generation and low energy requirement (Weerasundara et al 2021;Amen et al 2020). Many different natural and synthetic adsorbents have been tried to remove arsenic from water including industrial and agricultural wastes (Mohan and Pittman Jr 2007), Fe-Mn binary oxides (Zheng et al 2020), fly ash (Ochedi et al 2020), chitosan (Kloster et al 2020), activated carbon (Hashim et al 2019), and activated alumina (Tripathy and Raichur 2008). In recent years, zeolites have been used to remove many pollutants such as arsenic from water and wastewater due to their high surface area, easy availability, and low cost (Figueiredo and Quintelas 2014;Asere et al 2019).…”