Ying Yan,Yi Peng,Jing Wang,Ziyang Xiang,Yanmei Li,Junhui Yang,Jinglin Yin,Hongbo Xiao,Wenlei Wang
The reutilization of exhausted biochar is attracting extensive interest among researchers. In this study, the biochar generated from Chinese fir with natural regular porous structure that adsorbed Cd 2+ /Ni 2+ at different concentration levels was used as the precursor, and then combined with simple hydrothermal vulcanization and ion deposition to generate the p-n heterojunction between NiS and CdS compounds (NiS-CdS@C) in situ. The hybrids with 3 cycles of NiS deposition reduced the interfacial transmission resistance from 80 Ω to 40 Ω, and increased photocurrent density by 5 times, thus effectively promoting the separation of photogenerated electrons and holes. The simultaneous removal of As(III) and Cr(VI) was selected to evaluate the oxidation and reduction capacity of the visible light/NiS-CdS@C/oxalate system. The results indicated that 10 mg/L As(III) and Cr(VI) were completely and simultaneously removed with 0.75 mM oxalate addition within 40 min in the system, and the NiS-CdS@C presented good durability and stability for oxalate activation. Electron paramagnetic resonance (EPR) and quenching experiments demonstrated that oxalate was activated by holes under light to produce •CO 2 − and enhanced the generation of additional •OH and •O 2 − , further contributing to the oxidation of As(III) and reduction of Cr(VI).
Huidi Zhang,Yao Deng,Junhui Yang,Jinglin Yin,Jing Wang,Hongbo Xiao,Lizhi Wang,Cuihong Zhang,Wenlei Wang
In this study, MnPc intercalated Zn/Fe layered double hydroxides (MnPc/ZF−LDH) were synthesized by pillared intercalation modification with different MnPc intercalation amounts and used for the selective transformation and removal of As(III) from the arsenate-phosphate mixed solution. Fe−N bonds were constructed by the complexation of MnPc and iron ions on the Zn/Fe layered double hydroxides (ZF−LDH) interface. The DFT calculation results show that the binding energy of Fe−N bonded to arsenite (−3.75 eV) was higher than that of phosphate (−3.16 eV), resulting in MnPc/ZnFe−LDH exhibiting high As(III) selective adsorption performance and anchoring it rapidly in the arsenite -phosphate mixed solution. The maximum adsorption capacity of 1MnPc/ZF−LDH for As(III) could reach 180.7 mg·g −1 under dark conditions. MnPc also acts as a photosensitizer to provide more active species for the photocatalytic reaction. A series of experiments demonstrated that MnPc/ZF−LDH exhibits high As(III) selective photocatalytic performance. A total of 10 mg·L −1 of As(III) was completely removed in the reaction system within 50 min in a single As(III) environment. In an environment with As(III) and PO 4 3− , it achieved 80.0 % removal efficiency of As(III) and showed a good reuse effect. The introduction of MnPc could improve the utilization of visible light by the MnPc/ZnFe−LDH. The singlet oxygen generated from photoexciting MnPc leads to abundant ZnFe−LDH interface OH. In addition, MnPc/ZnFe−LDH shows good recyclability , making it a promising multifunctional material for the purification of arsenic-polluted sewage.
A novel microalgae-derived magnetic nanocomposite was engineered for As speciation. • First application of a Chlorella-based sorbent to sports supplements. • Ultra-trace arsenic determination achieved with 0.05 μg kg −1 detection limit. • Speciation revealed arsenic occurs mainly in less-toxic organic forms. Reliable speciation of inorganic arsenic in complex dietary supplements remains analytically challenging because of severe matrix interferences and the low concentrations of toxic arsenic species. In this study, a novel magnetic nanocomposite (ZnO–ZnFe₂O₄@CHL-MNCs) derived from Chlorella biomass was synthesized and employed as an efficient sorbent for ultrasound-assisted dispersive magnetic micro-solid phase extraction (UA-D-μ-SPE) prior to graphite furnace atomic absorption spectrometry (GFAAS). The synergistic integration of ZnO, ZnFe₂O₄, and the porous biomass-derived carbon matrix provided abundant active adsorption sites, high magnetic responsiveness, and rapid phase separation, resulting in efficient enrichment of inorganic arsenic species. Under the optimized conditions, the proposed method exhibited a linear range of 0.15–100 μg kg −1 (R 2 = 0.994), a limit of detection of 0.05 μg kg −1 , an enrichment factor of 163, and satisfactory intra- and inter-day precisions of 4.1% and 6.3%, respectively. The method was successfully validated using a certified reference material (NMIJ CRM 7503a) and subsequently applied to the determination of As(III), As(V), total inorganic arsenic, and total arsenic in commercial sport and bodybuilding supplements. Spike recoveries ranging from 92.7% to 106.7% confirmed negligible matrix effects and excellent analytical accuracy. The proposed strategy offers a rapid, sensitive, and environmentally friendly approach for arsenic speciation in complex food matrices and represents a promising alternative for routine food safety monitoring. Download: Download high-res image (240KB) Download: Download full-size image
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