Removal of As(V) by adsorption onto mixed rare earth oxides

Abstract

Arsenic pollution of water is a major problem faced worldwide. Arsenic is a suspected carcinogen in human beings and is harmful to other living beings. In the present study, a novel adsorbent was used to remove arsenate [As(V)] from synthetic solutions. The adsorbent, which is a mixture of rare earth oxides, was found to adsorb As(V) rapidly and effectively. The effect of various parameters such as contact time, initial concentration, pH, and adsorbent dose on adsorption efficiency was investigated. More than 90% of the adsorption occurred within the first 10 min and the kinetic rate constant was found to be about 3.5 mg min 21 . Adsorption efficiency was found to be dependent on the initial As(V) concentration, and the adsorption behavior followed the Langmuir adsorption model. The optimum pH was found to be 6.5. The presence of other ions such as nitrate, phosphate, sulphate, and silicate decreased the adsorption of As(V) by about 20-30%. The adsorbed As(V) could be desorbed easily by washing the adsorbent with pH 12 solution. This study demonstrates the applicability of naturally occurring rare earth oxides as selective adsorbents for As(V) from solutions. 1095

Surface-modified carbon black for As(V) removal

“…This method is simple and convenient, and also has the potential for regeneration and sludge-free operation. Various types of adsorbents such as biomaterials [15], metal oxide/hydroxides [16][17][18][19][20][21][22], zeolites [23], and activated carbon [24] have been developed.…”

Ceria nanoparticles supported on carbon nanotubes for the removal of arsenate from water

“…Arsenic pollution of water occurs due to various reasons, such as natural leaching of rocks containing arsenic, mining, processing of mineral deposits and discharge of industrial pollutants [8]. Although arsenic is needed as a micronutrient for human body, it is carcinogenic when consumed in larger quantities over a period.…”

“…Adsorption is one of the major methods employed for the removal of arsenic from water. Many kinds of adsorbents, such as carbon, rare earth oxides, lanthanum and yttrium impregnated alumina, amorphous iron hydroxide, polymers loaded with monoclinic hydrous zirconium oxide, ion exchange fiber, and lanthanum compounds, have been developed for the removal of arsenic from water [8][9][10][11][12][13]. Ceria has been reported to have good adsorption capacity for the removal of some anions and high resistance against attacks by acid [14].…”

Arsenic adsorption by polyvinyl pyrrolidone K25 coated cassava peel carbon from aqueous solution

“…FeSO 4 and CuSO 4 doped coir pith carbon [6], natural laterite [7], nanoscale zerovalent iron [8], sulphate modified iron oxide coated sand [9], orange juice residues [10], iron oxide loaded alginate beads [1], mixed rare earth oxides [11], activated neutralized red mud [12], modified mycelial pellets of Aspergillus fumigatus [13], pretreated tea fungal biomass [14], fresh and immobilized plant biomass [15] and iron containing mesoporous carbon [16].…”