Removal of arsenic from water using synthetic Fe 7 S 8 nanoparticles

Abstract

In the present study, pyrrhotite was used to remove arsenite and arsenate from aqueous solutions. The Fe7S8 was synthesized using a solvothermal synthetic method and it was characterized using XRD and SEM micrographs. Furthermore, the particle size for the nanomaterial Fe7S8 was determined to be 29.86 ± 0.87 nm using Scherer’s equation. During the pH profile studies, the optimum pH for the binding of As (III) and As (V) was determined to be pH 4. Batch isotherm studies were performed to determine the binding capacity of As(III) and As(V), which was determined to be 14.3 mg/g and 31.3 mg/g respectively for 25°C. The thermodynamic studies indicated that the ΔG for the sorption of As(III) and As(V) ranged from −115.5 to −0.96 kJ/mol, indicating a spontaneous process was occurring. The enthalpy indicated that an exothermic reaction was occurring during the adsorption in which the ΔH was −53.69 kJ/mol and −32.51 kJ/mol for As(III) and As(V) respectively. In addition, ΔS values for the reaction had negative values of −160.46 J/K and −99.77 J/K for the adsorption of As(III) and As(V) respectively which indicated that the reaction was spontaneous at low temperatures. Furthermore, the sorption for As(III) and As(V) was determined to follow the second order kinetics adsorption model.

Sorption of Cr(III) and Cr(VI) to K 2 Mn 4 O 9 nanomaterial a study of the effect of pH, time, temperature and interferences

“…?, a 0.05° step, and a 5s counting time. Once the XRD data was collected, it was analyzed using the Fullprof Suite of programs and the crystal structure of the K 2 Mn 4 O 9 [12, 17]. …”

“…The interest in nano-scale based adsorbents, such as nanoparticles, has increased in recent years as science advances. Nanotechnology allowed techniques using a smaller scale to be employed [12]. One example is the work done by Sharma et al whom investigated the adsorption of chromium(VI) to aluminum oxide nanoparticles in aqueous solution.…”

“…Whereas, Cantu et al have used Mn 3 O 4 nanoparticles to remove arsenic from aqueous solution showing binding capacities ranging from 2.5 mg/g to 54.4 mg/g [14]. Transition metal sulfides have also shown promise in the remediation of toxic elements from aqueous solution for example Fe 7 S 8 has shown promise in removing As(III) and As(V) [12]. Garcia et al have shown the removal of both Cr(III) and Cr(VI) from solution using ferrite and manganese substituted ferrite, which showed binding capacities up to 16 mg/g for Cr(III).…”

Nitrate Leaching from Sand and Pumice Geomedia Amended with Pyrogenic Carbon Materials

“…However, it was notable that the AC contained substantial amount of Fe (13.7%) and Al (1.6%) in its elemental composition (Table 1), indicating mineral inclusion of Fe and Al and possibly leading to better adsorption of nitrate. The Fe minerals such as hematite, goethite, and iron-oxide have been found to increase oxyanion adsorption such as arsenite and arsenate in the Fe-impregnated carbon materials though surface complexation between the Fe-O surface and oxyanion [20,21].…”

Study of the Adsorption of Arsenic (III and V) by Magnetite Nanoparticles Synthetized via AACVD

“…Heavy metals such as lead 1 , mercury 1 , cadmium 2 , chromium 3 , nickel 4 and arsenic metalloid 5 , are found naturally in the earth's crust; eventually these heavy metals can become contaminants in the air, surface water, groundwater, soil and other aquatic environments. In recent decades, the aquatic environment has been exposed to a large contamination mainly caused by the continuous discharges of pollutants containing heavy metals produced from anthropogenic sources 2 .…”