Arsenic removal from water/wastewater using adsorbents—A critical review

Nanoscale zero-valent iron (NZVI) was synthesized and tested for the removal of As(III), which is a highly toxic, mobile, and predominant arsenic species in anoxic groundwater. We used SEM-EDX, AFM, and XRD to characterize particle size, surface morphology, and corrosion layers formed on pristine NZVI and As(III)-treated NZVI. AFM results showed that particle size ranged from 1 to 120 nm. XRD and SEM results revealed that NZVI gradually converted to magnetite/maghemite corrosion products mixed with lepidocrocite over 60 d. Arsenic(III) adsorption kinetics were rapid and occurred on a scale of minutes following a pseudo-first-order rate expression with observed reaction rate constants (kobs) of 0.07−1.3 min-1 (at varied NZVI concentration). These values are about 1000× higher than kobs literature values for As(III) adsorption on micron size ZVI. Batch experiments were performed to determine the feasibility of NZVI as an adsorbent for As(III) treatment in groundwater as affected by initial As(III) concentra...

Removal of Arsenic(III) from Groundwater by Nanoscale Zero-Valent Iron

https://www.u-cursos.cl/usuario/7c1c0bd54f14c0722cefc0fa25ea186d/mi_blog/r/Lectura_clase_ingenieria_ambiental.pdf

Arsenic contamination, consequences and remediation techniques: a review

Remediation technologies for heavy metal contaminated groundwater.

The limitations of applying zero-valent iron technology in contaminants sequestration and the corresponding countermeasures: the development in zero-valent iron technology in the last two decades (1994-2014).

Zerovalent iron (Fe0) has tremendous potential as a remediation material for removal of arsenic from groundwater and drinking water. This study investigates the speciation of arsenate (As(V)) and arsenite (As(III)) after reaction with two Fe0 materials, their iron oxide corrosion products, and several model iron oxides. A variety of analytical techniques were used to study the reaction products including HPLC-hydride generation atomic absorption spectrometry, X-ray diffraction, scanning electron microscopy-energy-dispersive X-ray analysis, and X-ray absorption spectroscopy. The products of corrosion of Fe0 include lepidocrocite (γ-FeOOH), magnetite (Fe3O4), and/or maghemite (γ-Fe2O3), all of which indicate Fe(II) oxidation as an intermediate step in the Fe0 corrosion process. The in-situ Fe0 corrosion reaction caused a high As(III) and As(V) uptake with both Fe0 materials studied. Under aerobic conditions, the Fe0 corrosion reaction did not cause As(V) reduction to As(III) but did cause As(III) oxidation ...

Mathew L Hunt

Papers

Arsenic(III) and arsenic(V) reactions with zerovalent iron corrosion products.