In nearly all the cases of biotoxicity studies of silver nanoparticles (AgNPs), AgNPs used often have general dispersibility and wide size distribution, which may inevitably generate imprecise results. Herein, a kind of synthesis method by coupling effects of polyvinylpyrrolidone (PVP) and sodium tripolyphosphate (STPP) was proposed, in order to prepare AgNPs with better dispersibility and a stable size. Based on this, the preparation mechanism of AgNPs and the potential anti-algae toxicity were analyzed. UV-vis analysis showed that the particle size distribution of AgNPs prepared by co-protective agents was more uniform. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) were used to confirm that the obtained nano silver was of a high purity and stable size (~30 nm in diameter). Zeta potential and Fourier transform infrared spectroscopy (FTIR) analysis results indicated the synthesis mechanism of AgNPs by co-protective agents, more precisely, PVP limited the polynegative effect and prevented the linear induction of P₃O₁₀⁵⁻ produced by STPP during the growth of silver nuclei. Subsequently, Chlorella and Scenedesmus obliquus were utilized to test the toxicity of AgNPs, confirming that AgNPs synthesized through co-protective agents have potential inhibitory ability on algae, but not severe. This study provides a basic theory for the induction of synthetic AgNPs by various factors in the natural environment and a scientific reference for the environmental risk assessment.

The global environmental issue of soil contamination with antibiotic-resistance genes has garnered increased attention in recent years due to its impact on ecosystems and human health. Despite this recognition, researchers face challenges in comprehensively understanding the mechanisms underlying the production and dissemination of soil resistance genes, particularly in relation to their implications for human health. This lack of understanding poses a barrier to the development of effective and precise control strategies. Biochar, a sustainable material, exhibits favorable adsorption properties characterized by its large pores and specific surface area. Therefore, we propose to explore the potential application of biochar addition in soil resistance gene management. In order to establish a solid research foundation in this area, in this paper we review the mechanisms underlying the generation and accumulation of soil resistance genes over the last decade, along with their transmission pathways and interfacial interactions. Biochar may help repair soil resistance genes by affecting factors like antibiotic levels, environmental conditions, enzymatic activity, and gene migration mechanisms, opening up new research possibilities. Graphical Abstract

Although black phosphorus (BP) exhibits an outstanding performance in various fields due to its superior properties, its practical applications are seriously challenged by its low stability in oxygenated and/or aqueous environments. Most current passivation techniques focus on protecting bulk BP and require special equipment or the use of organic solvents and metallic reagents. Here, we present a facile, eco-friendly, and universally applicable method for inactivating BP nanosheets. Upon the hydrolytic co-condensing of 3-aminopropyl-triethoxysilane (APTES) and methyltrithoxysilane (MTEOS), a hydrophobic shell was formed on the surface of BP (SiO₂/BP-M), which retarded the degradation by preventing water from contacting the BP nanosheets. To expand the scope of applications, BP nanosheets were endowed with hydrophilicity by introducing a second hydrophilic silica shell layer (SiO₂/BP-MT). Taking advantage of the broadband absorption and photothermal conversion capacity of BP, we constructed a solar desalination device using a SiO₂/BP-MT film as a solar absorber along with a water transporter (non-textile) and thermal insulator (polystyrene foam). The SiO₂/BP-MT film-based evaporator possessed a solar evaporation rate of 1.63 kg m⁻² h⁻¹ under one sun illumination and remained stable for at least 10 days, demonstrating that the silica coating was effective in prolonging the life-span of the BP nanosheets in an aqueous environment.