Photo-induced protonation assisted nano primary battery for highly efficient immobilization of diverse heavy metal ions.

Highly-stable heavy metal ions (HMIs) appear long-term damage, while the existing remediation strategies struggle to effectively remove a variety of oppositely charged HMIs without releasing toxic substances. Here we construct an iron-copper primary battery-based nanocomposite, with photo-induced protonation effect, for effectively consolidating broad-spectrum HMIs. In FCPBN, Fe/Cu cell acts as the reaction impetus, and functional graphene oxide modified by carboxyl and UV-induced protonated 2-nitrobenzaldehyde serves as an auxiliary platform. Due to the groups and built-in electric fields under UV stimuli, FCPBN exhibits excellent affinity for ions, with a maximum adsorption rate constant of 974.26 g∙mg-1∙min-1 and facilitated electrons transfer, assisting to reduce 9 HMIs including Cr2O72-, AsO2-, Cd2+ in water from 0.03 to 3.89 ppb. The cost-efficiency, stability and collectability of the FCPBN during remediation, and the beneficial effects on polluted soil and the beings further demonstrate the splendid remediation performance without secondary pollution. This work is expected to remove multi-HMIs thoroughly and sustainably, which tackles an environmental application challenge.

Synthesis of Iron-Based Carbon Microspheres with Tobacco Waste Liquid and Waste Iron Residue for Cd(II) Removal from Water and Soil.

Herein, a novel magnetic iron-based carbon microsphere was prepared by cohydrothermal treatment of tobacco waste liquid (TWL) and waste iron residue (WIR) to form WIR@TWL. After that, WIR@TWL was coated with sodium polyacrylate (S.P.) to fabricate WIR@TWL@SP, whose removal efficiency for bivalent cadmium (Cd(II)) was studied in water and soil. As a result, WIR@TWL@SP possessed a high Cd(II) removal efficiency, which could reach 98.5% within 2 h. The adsorption process was consistent with the pseudo-second-order kinetic model because of the higher value of adjusted R2 (0.99). The thermodynamic data showed that the adsorption process was spontaneous (ΔG° < 0) and exothermic (ΔH° = 32.42 KJ·mol-1 > 0). Cd(II) removal mechanisms also include cation exchange, electrostatic attraction, hydrogen-bond interaction, and cation-π interaction. Notably, pot experiments demonstrated that WIR@TWL@SP could effectively reduce Cd absorption by plants in water and soil. Thus, this study offers an effective method for remediating Cd(II)-contaminated water and soil and may have a practical application value.