Removal of Trace Arsenite through Simultaneous Photocatalytic Oxidation and Adsorption by Magnetic Fe₃O₄@PpPDA@TiO₂ Core–Shell Nanoparticles

Abstract

Efficient removal of trace arsenites [As­(III)] in groundwater is a big challenge worldwide. In this study, magnetic Fe3O4@poly­(p-phenylenediamine)@TiO2 (Fe3O4@PpPDA@TiO2) core–shell nanoparticles were synthesized for As­(III) ions removal via the photocatalytic oxidation–adsorption process. Under dark conditions, the As­(III) adsorption on the as-synthesized core–shell nanoparticles obeyed the pseudo-second-order kinetic model and reached adsorption equilibrium within 45 min with a removal efficiency of 36.5%. Under visible-light irradiation, approximately 92% of As­(III) ions were transformed into relatively low-toxic As­(V) ions via the Fe3O4@PpPDA@TiO2 core–shell nanoparticles, and the arsenic removal efficiency increased dramatically to about 81% owing to As­(V) ions being simultaneously adsorbed on the nanocomposite surfaces. The photocatalytic oxidation mechanisms were attributed to the synergism of photogenerated holes, hydroxyl radicals, and superoxide radicals. The as-synthesized Fe3O4@PpPDA@TiO2 core–shell nanoparticles are potentially useful in purifying the trace As­(III)-contaminated groundwater owing to their easy magnetic separation, high optical quantum efficiency, and visible-light photocatalytic activity.

N‐Doped Porous Carbon Derived from Solvent‐Free Synthesis of Cross‐Linked Triazine Polymers for Simultaneously Achieving CO2 Capture and Supercapacitors

“…C 1s spectrum of TCLP (Figure 3b) displays four peaks with binding energies at 284.7, 286.2, 286.8, and 288.7 eV, which are ascribed to CÀ H, CÀ H, CÀ O, and C=O, respectively. [24] After activating reaction, the wide scan XPS spectrum (Figure S3) displays the existence of C, N, and O element on the surface of A-TCLP-700-1. Notably, the N content of 11.51 % still remained under such a high temperature activation reaction.…”

Single-Step Hydrothermal Synthesis of Biochar from H3PO4-Activated Lettuce Waste for Efficient Adsorption of Cd(II) in Aqueous Solution

“…The main characteristic FTIR bands were observed to include −OH, P=O, C−O, C−C, and C−N groups [ 9 , 25 , 26 ]. The stretching vibration of O−H in the hydroxyl groups and carboxyl groups leads to the appearance of peaks at 3454 cm −1 and 1641 cm −1 , respectively [ 27 ]. The peak at 1049 cm −1 was related to the bonds of P=O, while the band 1117 cm −1 was assigned to C−O, C−X, or C−C stretching vibration.…”

Removal of Arsenate From Groundwater by Cathode of Bioelectrochemical System Through Microbial Electrosorption, Reduction, and Sulfuration

“…Arsenic (As) contamination in groundwater possesses a serious threat to human and ecosystem health globally due to the high toxicity and ubiquity of As (Rodriguez-Freire et al, 2016;Wang et al, 2020). As in groundwater originates from the natural weathering, dissolution of As-bearing minerals (Smedley and Kinniburgh, 2002;Garelick et al, 2008), and anthropogenic activities such as the semiconductor industry, alloy manufacturing, and agricultural production (Mandal and Suzuki, 2002;Liu et al, 2015;Peng et al, 2018).…”

“…Generally, As(III) is easily oxidized to As(V) (Zhou et al, 2013). Thus, the oxidization of As(III) to As(V) as a pretreatment has been regarded as an efficient approach to remove As(III) (Nidheesh et al, 2020;Wang et al, 2020). However, treatments for As decontamination of shallow groundwater are focused on As(V) removal (Chen et al, 2018) given that As(V) dominates As species in shallow ground water.…”