Stabilization of nanoscale zero-valent iron (nZVI) with modified biochar for Cr(VI) removal from aqueous solution

Preparation of Activated Carbon Supported Bead String Structure Nano Zero Valent Iron in a Polyethylene Glycol-Aqueous Solution and Its Efficient Treatment of Cr(VI) Wastewater

“…Considering the above reactions in the system, an increase in the H + concentration can cause Reactions (1) and (2) to move in the positive reaction direction, thereby causing a large amount of Cr(VI) to be converted to Cr(III). Thus, a great amount of Cr(III) is coprecipitated with trivalent iron ions to produce insoluble iron-chromium hydroxides (such as Cr x Fe 1−x (OH) 3 and Cr x Fe 1−x OOH). During previous studies, ZVI particles have significantly affected the removal of Cr(VI) or other contaminants only when the system is at pH ≤ 6 [16,17,30,47].…”

“…Chromium is widely used in lots of industrial productions such as paper making, electroplating, dye manufacturing, leather tanning and paint manufacturing [1][2][3]. Due to loopholes in mining, smelting, use and disposal processes, chromium has caused many incidences of water contamination in industrialized areas, especially in China's Bohai Rim region with developed industry [3,4]. Chromium primarily exists as Cr(III) and Cr(VI) in the natural environment, and Cr(VI) is more soluble and toxic than Cr(III) [5,6].…”

“…Chromium primarily exists as Cr(III) and Cr(VI) in the natural environment, and Cr(VI) is more soluble and toxic than Cr(III) [5,6]. Cr(VI) can cause a series of health problems ranging from skin irritation to lung carcinomas [3,7]. The US Environmental Protection Agency (EPA) issues the national primary drinking water regulations, which stipulate a maximum concentration of 0.1 mg/L total chromium in drinking water [8].…”

“…However, limitations remain for applying nZVI technology to contaminant control due to the agglomeration tendency of nZVI particles [12,13]. The nZVI particles are prone to agglomeration, causing obvious decreases in the reduction capacity and specific surface area of the particles [3,12,14,15]. Moreover, the reaction of nZVI and Cr(VI) may be inhibited by their precipitated product, which is deposited on the metal surface and thus limits further reactions.…”

Preparation of Biomass Activated Carbon Supported Nanoscale Zero-Valent Iron (Nzvi) and Its Application in Decolorization of Methyl Orange from Aqueous Solution

“…The removal percentage of MO can be effectively improved with higher temperature, larger BC-nZVI dosage, and lower initial concentration of MO at the pH of 7 condition. 2 of 11 carrier, such as kaolinite [14], bentonite [15], resin [16], activated carbon [17], mesoporous carbon [18], mesoporous silica [19], titanium oxide [20], pumice [1,21], and grapheme [22], through the liquid phase reduction method. Nevertheless, there still has some problems associated with method, such as low production efficiency, high production cost, and large amounts of hydrogen the generation during the preparation process [23,24].…”