Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202507030
Arsenic is a toxic metalloid predominantly present in water as As(V) and As(III), whose speciation governs toxicity and mobility. Conventional speciation methods (HPLC-ICP-MS, IC-HG-AFS) offer ultralow detection limits but suffer from high cost, long analysis times, and non-portability, hindering on-site rapid monitoring. This study presents a sulfide-based spectrophotometric method exploiting the quantitative reaction between As(V) and S2− to form monothioarsenate (H3AsO3S) with a characteristic absorption at 233 nm. Under optimized conditions (H+ concentration 1 mol·L−1, Na2S dosage 5 mmol·L−1, reaction time 3 min, N2 purging 2 min), As(V) is directly quantified. Total arsenic is determined after complete oxidation of As(III) to As(V) using NaClO (10 mmol·L−1, pH 12, 5 min), and As(III) is obtained by difference. The method exhibits linearity over 0.5–50 mg·L−1 (A = 0.0209c + 0.0627, R² = 0.999), a detection limit of 0.17 mg·L−1, spike recoveries of 101.9%–104.1%, and relative standard deviation of 1.06%. Validation against real industrial wastewater samples showed relative deviations <10% compared with HPLC-ICP-MS and IC-HG-AFS. Total analysis time is within 15 min. The method is simple, cost-effective, and suitable for field monitoring.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3993-y
Conventional liquid-phase in-situ synthesis of Cu-TiB2 composites often suffers from coarse and non-uniformly distributed reinforcements, stemming from insufficient understanding and control over the in-situ nucleation and growth mechanisms of TiB2 particles. This study introduces a novel melt dispersion-turbulent mixing (MDTM) in-situ reaction technology to fabricate high-performance Cu-TiB2 composites. The MDTM strategy synergistically refines reaction micro-regions by reducing the initial melt droplet size via melt dispersion while enhancing solute convection via turbulence, promoting high-density nucleation and refinement of TiB2 particles. Based on turbulence characteristics and in-situ reaction kinetics, we optimized the melt disperser parameters and established a quantitative model linking particle size to disperser rotation speed and reactant solute concentration. It was found that disperser rotation speed governs three distinct nucleation and growth mechanisms for TiB2 particles. Low-density nucleation at low disperser rotation speeds (0–50 r/min) leads to coarse TiB2 particles. At medium rotation speeds (100–150 r/min), the refinement of micro-regions in the dual-melt reaction achieves high-density TiB2 nucleation. Conversely, at high rotation speeds (150–200 r/min), intense turbulence weakens the nucleation driving force and induces TiB2 particle coarsening. This work provides new insights into liquid-phase in-situ reaction mechanisms and offers a novel, controllable route for fabricating high-performance micro/nano particle-reinforced metal matrix composites.
Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202511057
To investigate the effects of applying sewage sludge aerobic fermentation products on antibiotic resistance genes (ARGs) in the rhizosphere soil and phyllosphere of pakchoi (Brassica chinensis L.), field experiments were conducted with three treatments: sludge product (sludge group), chemical fertilizer (fertilizer group), and no fertilizer (control). Antibiotic residues, abundances of ARGs and mobile genetic elements (MGEs) were measured in rhizosphere soil and phyllosphere, and microbial community composition and virulence factor (VF) contributions were annotated via metagenomics. Results showed that antibiotic concentrations in rhizosphere soil were generally higher than in phyllosphere. Compared with control, sludge application increased soil antibiotic content by 12.70%, whereas fertilizer increased it by only ~3%, indicating a more significant exogenous input from sludge. At the resistance level, total ARG abundances in rhizosphere soil and phyllosphere of the sludge group increased by 25.47% and 73.08%, respectively, relative to control, with concurrent increases in beta-lactam resistance genes and MGEs such as integron intI1. Sludge application may enhance integron-mediated gene capture and horizontal transfer potential, driving resistance risk accumulation in both phyllosphere and rhizosphere soil. Conversely, fertilizer application reduced ARG abundances by 53.40% in rhizosphere soil and 13.50% in phyllosphere compared with control, consistent with decreased microbial community abundance and diversity, suggesting that reduction of host bacteria and dissemination vectors was a key reason. In community structure, Proteobacteria dominated the phyllosphere, while Chloroflexi dominated rhizosphere soil. Correlation networks identified Sphaerobacter thermophilus and Aggregatilinea lenta positively correlated with multiple ARGs (r≈0.95–1.00), whereas Solirubrobacter sp. CPCC_204708 was negatively correlated (r≈−0.91). Virulence factor contributions followed trends similar to ARGs. Sludge fermentation products simultaneously increased ARG prevalence and related risk indicators in both rhizosphere soil and phyllosphere of pakchoi, providing a reference for risk identification and safe application of sludge fermentation products in agriculture.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4097-3
The on-demand patterning of two-dimensional transition metal dichalcogenides (TMDs) with tailored edges is critical for electronic and optoelectronic applications but remains technically challenging. Here, we report a stress-guided anisotropic etching strategy for producing large-area, well-ordered MoS2 nanostructures, including nano-ribbons and nano-squares, without templates. By applying uniaxial cumulative stress followed by selective thermal etching, MoS2 monolayers are statistically etched into ribbon-like structures whose width inversely correlates with applied stress magnitude. The newly etched edges are macroscopically straight or serrated, predominantly Mo-zigzag terminated, and enhance photoluminescence by a factor of ~8.0. The edge type depends on the angle between stress direction and crystallographic orientation, corroborated by theoretical calculations. Biaxial stressing generates well-defined nano-squares, offering a scalable, versatile patterning route for engineering 2D materials with tailored functional edges, promising for electrocatalytic and optoelectronic applications.