Hexavalent chromium elimination from wastewater by integrated micro-electrolysis composites synthesized from red mud and rice straw via a facile one-pot method

Abstract

The widely spread chromium (Cr) contamination is rising environmental concerns, while the reutilization of agro-industrial by-products are also urgently demanded due to their potential risks. In this study, we prepared the integrated micro-electrolysis composites (IMC) through a facile one-pot method with red mud and rice straw. The effects of components relatively mass ratios as well as pyrolysis temperature were analyzed. The XRD, XPS, SEM, FTIR, and various techniques proved the IMC was successfully synthesized, which was also used to analyze the reaction mechanisms. In this study, the dosage of IMC, pH, adsorption time, and temperature of adsorption processes were explored, in the adsorption experiment of Cr(VI), dosage of IMC was 2 g/L (pH 6, 25 °C, and 200 rpm) for isothermal, while the concentration and contact time were also varied. According to the batch experiments, IMC exhibited acceptable removal capacity (190.6 mg/g) on Cr(VI) and the efficiency reached 97.74%. The removal mechanisms of adsorbed Cr(VI) were mainly elaborated as chemical reduction, complexation, co-precipitation, and physical adherence. All these results shed light on the facile preparation and agro-industrial by-products recycled as engineering materials for the heavy metals decontamination in wastewater.

Cadmium Elimination via Magnetic Biochar Derived from Cow Manure: Parameter Optimization and Mechanism Insights

“…The analysis of XRD spectra was applied to determine the existence of crystalline minerals and analyze their structure of MCB. The fluctuating peaks of the typical amorphous carbon and graphite carbon structures were about 22 • and 44 • , respectively, and these peaks were common in biochar characterization, indicating that MCB belonged to biochar material [35]. But the amorphous carbon structure of MCB disappeared for the disappearance of these characteristic peaks, which indicated that the modification substantially changed the carbon structure in MCB [10].…”

How to Remediate Heavy Metal Contamination in Soil?

“…Earthworms can both increase soil fertility and encourage plant root growth (43). Hexavalent chromium was removed from contaminated soil using a combination of bacteria, sludge, and straw (44), and the findings indicated that 1% straw plus 1% Compound bacteria and 30% sludge together reduce soil chromium by 96.6%, and this combination can provide the greatest effect.…”

Enhanced Adsorptivity of Hexavalent Chromium in Aqueous Solutions Using CTS@nZVI Modified Wheat Straw-Derived Porous Carbon

“…The issue of heavy metal pollution in aquatic environments has intensified, posing a significant challenge due to the indiscriminate discharge of industrial waste, mining effluents, sewage irrigation, and chemical products [ 1 ]. Among these contaminants, chromium pollution stands out as a particularly pressing concern due to its inherent toxicity and deleterious effects on aquatic ecosystems [ 2 ]. Hexavalent chromium (Cr(VI)), in particular, poses a direct threat to human health.…”