Adsorption of Arsenate from Aqueous Solution onto Modified Vietnamese Bentonite

Abstract

In this study, pillared layered clays were prepared by modifying Vietnamese bentonite with polymeric Al and Fe. The obtained materials were characteristic of X-ray diffraction analysis, thermal analysis, and nitrogen adsorption/desorption isotherms. The results indicated that hydroxy-aluminum ([Al13O4(OH)24(H2O)12]7+) and poly-hydroxyl-Fe or polyoxo-Fe cations were intercalated into layers of clay, resulting in an increase of d001 values and of the specific surface areas compared with those of initial bentonite. Modified bentonites were employed to adsorb As(V) from aqueous solution. The adsorption of As(V) was strongly dependent on solution pH, and the maximum adsorption of modified bentonites was obtained in the pH 3.0 for Fe-bentonite and the pH 4.0 for Al-bentonite. The equilibrium adsorption study showed that the data were well fit by the Langmuir isotherm model. The maximum monolayer adsorption capacity of As(V) at 30°C derived from the Langmuir equation was 35.71 mg/g for Al-bentonite and 18.98 mg/g for Fe-bentonite. Adsorption kinetics, thermodynamics, and reusability of modified bentonites have been addressed.

Arsenic (III) Removal from Aqueous Water by Indigenous Iron Ore Adsorbent from Balochistan Province of Pakistan

“…In Table 2, the results of kf and 1/n exhibit that the sorption data is well satisfied and these values indicate the capacity and intensity of sorption, respectively. The experimental model has confirmed to be persistent with exponential dissemination of active pores, distinctive of heterogeneous surfaces [22].…”

“…The elemental iron or iron hydroxides have a high affinity for As (III) and As (V) are extensively used for the removal of arsenic [18][19][20]. Zero-valent (Fe) powders have been used or added to household filters to remove arsenic from contaminated groundwater [21][22]. There are promising material because of their large surface area, but cannot be applied in a fixed bed column, because these are fine powders and require to be converted to granular material [23].…”

Immobile Iron-Rich Particles Promote Arsenic Retention and Regulate Arsenic Biotransformation in Treatment Wetlands

“…The maximum adsorption ( q m ) index suggested that the amendment of IIRP significantly improved the As­(V) and As­(III) adsorption capacity (Table S4). The Langmuir parameter K L can reflect the binding energy and the adsorption stability. , Accordingly, the adsorption stabilities of As­(V) and As­(III) by iron-rich particles were higher than those by the gravel substrate as indicated by the higher K L . This is in accordance with the results of sequential extractions, which showed that the adsorbed As was more stable in IIRP-TWs as compared to that in C-TWs.…”

Studies on Hydration Swelling and Bound Water Type of Sodium- and Polymer-Modified Calcium Bentonite

“…The research on modification of clay minerals is applicable in various fields, and polymer modification attracts considerable attention. For example, the modified bentonite is used in water treatment to absorb organic pollutants in water, and the modified clay is used to block the migration of pollutants as well as solidify and stabilize heavy metal pollutants in EBSs [38][39][40][41]. Organic polymer modification of bentonite can increase the adsorption of organic pollutants, which has a better effect than inorganic modified materials [42].…”