Activation process of air stable nanoscale zero-valent iron particles
نویسندگان
چکیده
Nanoscale Zero Valent Iron (nZVI) represents a promising material for subsurface water remediation technology. However, dry, bare nZVI particles are highly reactive, being pyrophoric when they are in contact with air. The current trends of nZVI manufacturing lead to the surface passivation of dry nZVI particles with a thin oxide layer, which entails a decrease in their reactivity. In this work an activation procedure to recover the reactivity of air-stable nZVI particles is presented. The method consists of exposing nZVI to water for 36 hours just before the reaction with the pollutants. To assess the increase in nZVI reactivity based on the activation procedure, three types of nZVI particles with different oxide shell thicknesses have been tested for Cr(VI) removal. The two types of air-stable nZVI particles with an oxide shell thickness of around 3.4 and 6.5 nm increased their reactivity by a factor of 4.7 and 3.4 after activation, respectively. However, the pyrophoric nZVI particles displayed no significant improvement in reactivity. The improvement in reactivity is related mainly to the degradation of the oxide shell, which enhances electron transfer and leads secondarily to an increase in the specific surface area of the nZVI after the activation process. In order to validate the activation process, additional tests with selected chlorinated compounds demonstrated an increase in the degradation rate by activated
منابع مشابه
Application of synthesized nanoscale zero-valent iron in the treatment of dye solution containing Basic Yellow 28
Nanoscale zero-valent iron NZVI particles were synthesized by the aqueous phase borohydride reduction method, and the synthesized NZVI particles were used for the degradation of Basic Yellow 28 BY28 dye in aqueous solution. The influence of experimental variables such as reaction time, NZVI particle dosage and pH were studied on the decolorization of BY28. Mixing an aqueous solution of 100 mg L...
متن کاملNew Method of Synthesis of Stable Zero Valent Iron Nanoparticles (Nzvi) by Chelating Agent Diethylene Triamine Penta Acetic Acid (DTPA) and Removal of Radioactive Uranium From Ground Water by using Iron Nanoparticle
Nowdays, iron nanoparticles due to their unique characteristics are used in all of sciences and technology. These nano particles due to their electrical, magnetic, optical and catalytic properties and having high area and activity that is promped by their small size and most importantly many scientists from the entire world are interested in th...
متن کاملUse of nanoscale zero-valent iron to improve the shear strength parameters of gas oil contaminated clay
In recent years, the nanoscale zero-valent iron (NZVI) particles have been used successfully for the degradation of hydrocarboncompounds and remediation of other pollutants. Nevertheless, as far as we know, there is no specific study on the improvement of thegeotechnical properties of contaminated soils with hydrocarbon compounds by NZVI. This study used NZVI particles to remove gasoil in a cla...
متن کاملRemoval of Acid Red 18 dye from Aqueous Solutions Using Nanoscale Zero-Valent Iron
Background and Purpose:Organic dyes with a complex structure are often toxic, carcinogenic, mutagenic, non-biodegradation and stable in the environment and if released to the environment without treatment can endanger the environment and human health. The aim was to evaluate the performance nanoscalezero-valent iron (NZVI) in the removal of dye acid red 18 (AR18) from aqueous solutions. Materia...
متن کاملSonocatalytic degradation of p-chlorophenol by nanoscale zero-valent copper activated persulfate under US irradiation in aqueous solutions
In this study, nanoscale zero-valent copper (nZVC) as catalyst activated persulfate (PS) was used for the degradation of p-chlorophenol (p-CP) under ultrasonic (US) irradiation in aqueous solution. The effect of different operational parameters such as solution pH (3.5-10.5), PS concentration (1-7.5 mm/L), nZVC dosage (5-35 mg/L) and initial p-CP concentration (10-100 mg/L) were evaluated at di...
متن کامل