Selective removal of arsenic in water: A critical review

Abstract

Selective removal of arsenic (As) is the key challenge as this not only increases the efficiency of removal of the main As species (neutral As(III) and As(V) hydroxyl-anions) but also allows the reduction of waste significantly as it does not co-remove other solutes. It increase the capacity and lifetime of units, while lowering the cost of the process. A sustainable selective mitigation method should be considered in relation to the economic resources available, the ability of infrastructure to sustain water treatment and the options for reuse and/or safe disposal of treatment residuals. Several methods of selective As removal have been developed, such as precipitation, adsorption and modified iron and ligand exchange. There are two types of mechanisms involved with As removal: Coulombic or ion exchange; and Lewis acid-base interaction. Solution pH is one of the major controlling factors limiting removal efficiency since most of the above-mentioned methods depend on complexation through electrostatic effects. The different features of two different As species make the selective removal process more difficult, especially under natural conditions. Most of the selective As removal methods involve hydrated Fe(III) oxides through Lewis acid-base interaction. Microbiological methods have been studied recently for selective removal of As although there have been only a small number of studies; however, the method shows remarkable results and indicates positive prospects for the future. The biggest challenges in selective removal of As is the presence of phosphate in water which is chemically comparable with As(V).

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

“…Since As(III) is in the form of uncharged H 3 AsO 3 in the pH range of 6-9, where natural waters are most common, it can be removed from water much more difficult and with a lower efficiency than As(V). Therefore, oxidation of As(III) to As(V) takes place as a pretreatment process in most of the methods used for arsenic removal (Weerasundara et al 2021;Amen et al 2020). Many methods such as coagulation (Bora et al 2016;Pallier et al 2010), electrochemical processes (Goren and Kobya 2021;Kobya et al 2020), ion exchange (Lee et al 2017;Urbano et al 2012), membrane filtration (Nguyen et al 2009;Schmidt et al 2016), and adsorption (Das et al 2020) are used for removing arsenic from water in order to prevent the toxic effect on living forms and adverse effects on human health caused by arsenic in water resources.…”

“…Many methods such as coagulation (Bora et al 2016;Pallier et al 2010), electrochemical processes (Goren and Kobya 2021;Kobya et al 2020), ion exchange (Lee et al 2017;Urbano et al 2012), membrane filtration (Nguyen et al 2009;Schmidt et al 2016), and adsorption (Das et al 2020) are used for removing arsenic from water in order to prevent the toxic effect on living forms and adverse effects on human health caused by arsenic in water resources. 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).…”

Fabrication and Preliminary Assessment of Fixed Adsorption Column for Arsenic (As) Removal Using Local Rice Husk

“…T he high toxicity of arsenic is observed in groundwater [1]. Arsenic mostly occurs in the inorganic form in nature.…”

“…Arsenic mostly occurs in the inorganic form in nature. Various research outcomes highlight that arsenic is a carcinogenic element if used in excess amount in drinking water [1][2][3][4]. Arsenate is less poisonous and eager to migrate than Arsenite.…”

“…A significant number of treatment methodologies have been developed for removing arsenic traces from water, most of them emphasizing on industrial or large scale water treatment plants, however, the rural or small scale local treatment is not well established yet [12]. Different techniques including ion exchange, coagulation, membrane filtration, precipitation and adsorption have been applied for removing arsenic from groundwater of contaminated surface water, and synthetic or natural adsorbents are been developed besides lime softening technique to reduce arsenic concentrations [1][6] [21], however, economic constraints for these technologies is still a big challenge [16].…”