Fe₃O₄@Mesoporous-SiO₂@Chitosan@Polyaniline Core–Shell Nanoparticles as Recyclable Adsorbents and Reductants for Hexavalent Chromium

Abstract

In this work, we designed the Fe3O4@mesoporous-SiO2@chitosan@polyaniline core–shell nanoparticles (Fe3O4@mSiO2@CS@PANI, hence abbr. FSCP), which can be used to capture Cr­(VI) in wastewater. Rapid adsorption behavior and high removal capability (249.6 mg Cr­(VI) per gram of FSCP) were exhibited by this material. X-ray photoelectron spectroscopy (XPS) analysis demonstrates that Cr­(VI) was adsorbed and in situ reduced on FSCP at pH 2. Adsorption was facilitated by the electrostatic attraction of HCrO4 – and −N+C–/–N+H–, while the active −NH–/–N+H– sparked the reduction of Cr­(VI) to Cr­(III). Moreover, the coordination of the resulting Cr­(III) with the amino group promoted adsorption, thus achieving detoxification of Cr­(VI) in wastewater. After eight recycling experiments, the Cr­(VI) removal efficiency of this material is still more than 90%, indicating that this material has excellent stability and good application potential. Therefore, this magnetic adsorbent offers a potential solution for the successful handling of chromium-containing wastewater.

Smart Synthesis of Hollow Microporous Organic Capsules with a Polyaniline Modified Shell

“…[45][46][47] Moreover, protonated amine groups can capture and store H + from solution for reducing toxic Cr(VI) ions into a lower oxidation state nontoxic Cr(III). [48,49] As the adsorption and chemical reduction of Cr(VI) required the involvement of H + , lower pH is beneficial for Cr(VI) adsorption and reduction. It is notable that there is electrostatic repulsion force between -SO 3 and Cr(VI).…”

A novel carbazole-benzothiazole-based chemodosimeter for the chromogenic and fluorogenic recognition of CN−

“…1 Additionally, food safety issues and water pollution by poisonous anions have drawn attention with the development of science and technology nowadays. [2][3][4][5][6] Cyanide is one of the most well-known toxic anions, even at a lower concentration, which can be lethal to human beings, animals, and environment. Cyanide is currently extensively used in many industrial processes such as electroplating, petrochemicals, photography, steel production, gold mining, metallurgy, and the synthesis of resign and fibre due to its critical role in multi-functional reactions.…”

Graphene‐Oxide‐Coated, Polypyrrole‐Supported, Nano Zerovalent Iron Nanocomposites for Adsorption of Hexavalent Chromium from Wastewater

“…[12,13] Long-term exposure to hexavalent chromium more than the permissible limit can cause nausea, nervous disorder, kidney failure, liver diseases, and cancer. [14,15] The various technologies developed for Cr (VI) removal from water or wastewater streams include chemical precipitation, [16] ion exchange, [17] bioremediation, [18] photocatalytic reduction, [19] electrokinetic, [20] remediation membrane separation, [7] electrodialysis, [21] and adsorption. [22] Among these, the adsorption method is widely used in the cleaning of Cr (VI) contaminated water due to its wide range of raw materials and no by-products, easy recovery, simple operation, and high efficiency.…”

“…[22] Among these, the adsorption method is widely used in the cleaning of Cr (VI) contaminated water due to its wide range of raw materials and no by-products, easy recovery, simple operation, and high efficiency. The various adsorbents, including activated carbon, [23,24] zeolites, [25,26] clays, [27,28] doublelayered hydroxide, [29,30] chitosan, [18,31] conducting polymer, [7,32] biochar, [33,34] metal-organic frameworks, [35] graphene, [36,37] and metal phosphate, [12,13] had been utilized to remove Cr (VI) from wastewater.…”