Environmental Science: Nano最新文献

Biomass burning (BB) emits a substantial amount of trace gases, and their atmospheric oxidation makes a large contribution to secondary organic aerosol (SOA) formation. However, the potential interactive effect of mixed volatile organic compounds (VOCs) from BB on SOA formation remains largely unknown. Here, we studied the molecular composition and optical properties of nanoscale SOA formed from the mixture of two typical VOCs in BB emissions (styrene and furan) with distinct chemical characteristics. The ratio of furan to styrene was controlled within a range of 0.5–10, based on actual emission ratios. By investigating SOA variations at the molecular level, we found that the SOA yield and light absorption in the furan–styrene mixture system were significantly lower than those in the styrene system. The decrease in SOA yield in the mixture experiments might be explained by changes in the distribution of organic aerosol components. Specifically, the addition of furan reduced the proportion of low-volatility organic compounds and increased the proportion of semi-volatile organic compounds. Tandem mass spectrometry (MS/MS) analysis indicated that the reduction in light absorption after furan addition could be attributed to the suppressed formation of nitrophenolic compounds, since typical chromophores such as C₆H₅NO₃ and C₆H₅NO₄ were only identified in styrene SOA. These findings highlight the complex interactions between organic gases in BB emissions and their significant impact on SOA formation and optical properties.

Exploring the adsorption of organic compounds onto boron nitride nanotubes (BNNTs) is essential for designing advanced BNNT-based absorbents to remove emerging organic pollutants from the environment. Herein, density functional theory (DFT) computations were carried out for exploring the adsorption of 30 organic compounds onto 14 BNNTs with varying diameters and types of chirality. Furthermore, 14 predictive models based on the fine-tuned theoretical linear solvation energy relationship (TLSER) were established for estimating the adsorption energy (E_ad) values onto BNNTs. These prediction models are applicable to aliphatic and aromatic hydrocarbons featuring diverse substituents, i.e., –CH₃, –NH₂, –NO₂, –OH, –F, –CN, –C(O)CH₃, –CH₂CH₂OH, –CH₂OH, –CH₂CH₃ and –CH₂CH₂CH₃. Besides, the results imply that the adsorption energies can be enhanced by increasing the diameter of BNNTs. The functional groups of the organic compounds can further promote the adsorption onto BNNTs. The more functional groups, the more effective the adsorption. The dispersion interactions were identified as the primary driving forces in the adsorption, while the hydrogen-donating ability had minimal effects on the adsorption. These results provide molecular-level insights into diverse organic compound adsorption onto BNNTs with different diameters and types of chirality, and also offer efficient tools for predicting the adsorption behavior onto BNNTs so as to rationally design high-performance BNNT-based absorbents.

In this work, we present three different pathways to render commercial melamine sponges, both magnetic and hydrophobic, thereby offering them the capacity to effectively and selectively remove crude oil and heavy metals from aqueous environments. The magnetic properties were endowed by the deposition of as-synthesized iron oxide nanoparticles, functionalized with hydrophobic oleic acid and oleylamine ligands, via a large-scale synthesis. Aiming for an even higher hydrophobicity, terminal vinyl groups were attached to the pristine and modified sponges through a sol–gel hydrolysis of VTES@SiO₂. The magnetic materials were thoroughly characterized and evaluated for their efficiency in water purification applications, regarding the adsorption of crude oil and heavy metal pollutants. Each pathway of preparation was effectively practical for a different application. The initial coating of the sponges with a hydrophobic layer (Sp-h-m) enhanced the adsorption and the retention of iron oxide nanoparticles, resulting in materials with a maximum magnetization of 25 × 10⁻³ emu. This modified sponge also exhibited the highest removal of metal ions (As³⁺ and Hg²⁺) from aqueous solutions within 60 minutes, and its extraction efficiency was evaluated in systems with single metal ions (250 ppm) and in the removal of metal ions (As³⁺ and Hg²⁺) from aqueous solutions within the same time frame. It was evaluated for its extraction efficiency in systems with single metal ions (250 ppm) and under competitive conditions (500 ppm of toxic metals in total). The coating with a hydrophobic layer, following the deposition of the magnetic nanoparticles (Sp-m-h), led to further improvement of the sponge's hydrophobicity (from 129° to 140° water contact angle; WCA), excellent selectivity to crude oil, and water repellency. The magnetically modified sponges exhibited significant initial adsorption capacities (60–100 g g⁻¹) and average adsorption capacities (35–65 g g⁻¹) over 15 cycles. The high selectivity, adsorption/desorption efficiency (up to 99.8%), their adsorption capacity for As and Hg metal ions and their responses to external magnetic fields confirmed the suitability of the developed magnetic sponges for water purification systems. The versatility of the proposed modification route allows the preparation and optimization of specific magnetic sponges for targeted applications.

Seed germination is a critical and environmentally sensitive stage. Cerium oxide nanomaterials (CeO₂ NMs) have been proven to enhance crop productivity. However, it remains unclear how soil microbes mediate the effects of CeO₂ NMs on germination in different soils. In this study, four soils applied with different concentrations of CeO₂ NMs were studied. Ten mg L⁻¹ CeO₂ NMs significantly promoted wheat growth in yellow-brown soil, red soil, and fluvo-aquic soil (sandy soil), while 50 mg L⁻¹ was optimal for fluvo-aquic soil (garden soil), indicating the promotion effect relates to both NM concentration and soil type. The germination index, root length, and chlorophyll content were highest in sandy soil. Partial least squares path modeling (PLS-PM) analysis showed that soil physicochemical properties shaped bacterial communities, which in turn impact wheat seed germination and growth. CeO₂ NMs upregulated the abundances of beneficial bacteria (Pseudomonas, Massilia, Ramlibacter, Bacillus, and Enterobacter) by 28.5–576.6% (without seeds) and 22.1–132.7% (with seeds), creating favorable soil conditions for germination. The beneficial bacteria were recruited by increasing soil organic acids, fatty acids, amino acids, and nucleotides by 2.12–4.09-fold. CeO₂ NMs also entered seeds; NMs increased α-amylase activity (28.4–69.6%) and soluble sugar content (20.7–33.8%) to supply germination energy. The phytohormone levels were also altered, with increasing gibberellin (6.6–13.4%) and auxin (16.8–34.3%) and decreasing abscisic acid (10.7–18.9%) while enhancing the tricarboxylic acid (TCA) cycle and glycolysis. Wheat grows optimally in sandy soil due to its rich nutrients, with CeO₂ NMs upregulating more soil metabolites that recruit Bacillus and Massilia. This microbial mediation also achieves the highest levels of seed gibberellin (GA) and α-amylase activity, collectively promoting growth. This study offers insights into the microbial-mediated promotion of wheat seed germination for sustainable agricultural practices and also provides a basis for assessing the potential environmental impacts of CeO₂ NMs in agricultural ecosystems.

A plant growth promoter is a substance or microorganism that enhances the growth and development of plants, providing an agricultural solution. These promoters work by improving nutrient uptake, enhancing root and shoot growth, increasing photosynthesis, and helping plants tolerate stress. This work uses coal-derived carbon quantum dots (CQDs) as plant growth promoters (PGPs) due to their unique physicochemical properties. The PGPs (CQDs) are synthesized using an ultrasonic-assisted chemical oxidation technique with coal as a source material. The structure and morphology of the prepared PGPs were examined using HR-TEM, FT-IR, and UV-vis spectrophotometry. XPS analysis of the CQDs showed the presence of nitrogen and sulfur self-co-doped heteroatoms and carbon and oxygen incorporated through various surface and edge functional groups. Phytological and qRT-PCR analyses of Withania somnifera reveal that coal-derived CQDs significantly enhance plant growth and metabolite content. This study demonstrates the potential of coal-based CQDs as sustainable nanotechnology-based plant growth promoters.

In response to the significant global crop losses caused by insect pests, which affect up to 40% of crops annually, there is an urgent need for safer food protection methods. This study addresses this need by proactively developing a safe and sustainable by design (SSbD) alternative to synthetic pesticides. Guided by the EC-JRC SSbD framework, the research focuses on an advanced low density polyethylene (LDPE) film embedding a multicomponent nanomaterial (MCNM), consisting of bentonite nanoclays and clove essential oil (BNT–CEO), designed to repel beetles. In detail, a three-step premarket safe-by-design assessment was performed. The first step was the safety assessment of the BNT–CEO material through i) physicochemical characterization, ii) screening for potential hazards of chemical precursors, and iii) preliminary in vitro toxicity tests. Afterwards, worker safety during both BNT–CEO synthesis and LDPE(BNT–CEO) production was assessed, analyzing dust generation and workers' potential exposure through an industrial hygiene survey followed by occupational monitoring. Lastly, consumers' safety was covered assessing the LDPE(BNT–CEO) film degradation and potential for migration of chemicals, by comparing pristine and accelerated-aged samples. Compliance with EU Regulation 10/2011 was verified by analyzing the migration of substances into food simulants. The integration of these safety evaluations early in the design process of BNT–CEO and LDPE(BNT–CEO) allowed confirmation of the material's compliance with regulatory limits and contributed to the validation of the assessment procedure as proposed by the SSbD framework. The approach here applied demonstrates how to successfully balance effective pest protection with minimal impact on consumers and workers, paving the way for the development of safer and sustainable food packaging solutions.

Molecular oxygen (O₂) activation by iron-based materials represents a sustainable strategy for organic pollutant removal. However, the inherently high energy barrier of O₂ activation limits the generation of reactive species, especially nonradical species. Here, we demonstrate that cobalt (Co) doping of pyrite (FeS₂) significantly enhances both radical and nonradical pathways of O₂ activation by creating dual active sites. Specifically, quenching experiments and theoretical calculation demonstrate that the Fe atoms are the primary sites of hydroxyl radical (·OH) generation. Co doping upshifts the Fe d-band center toward the Fermi level (from −2.02 to −1.63 eV), thereby facilitating ·OH generation. Simultaneously, electron paramagnetic resonance spectroscopy results indicate that Co doping promotes generation of sulfur vacancies (SVs), which act as singlet oxygen (¹O₂)-producing sites. The divergent O₂ transformation pathways at the Fe and SVs sites are attributed to differences in adsorption affinity of *OOH intermediate at these sites. The relative contributions of the two pathways can be tuned by varying the Co dopant level, enabling efficient degradation of diverse contaminants, including chlorinated phenols, chlorinated aliphatic hydrocarbons, and antibiotics. This work elucidates a dual-site catalytic mechanism for regulation of radical and nonradical pathways of O₂ activation, and can guide the design of O₂-activating materials for environmental remediation via advanced oxidation processes.

The present study explores the role of zinc oxide nanoparticles (ZnONPs) and silver nanoparticles (AgNPs) in enhancing the micropropagation efficiency of Kaempferia galanga L., a medicinal plant known for its rich phytochemical profile. ZnONPs and AgNPs were synthesized and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and ultraviolet-visible (UV-vis) spectroscopy to confirm their purity and crystalline structure. Their effects were evaluated by supplementing Murashige and Skoog (MS) medium with various concentrations of nanoparticles and conventional plant growth regulators, including 6-benzylaminopurine (BAP), kinetin (KN), α-naphthalene acetic acid (NAA), indole-3-acetic acid (IAA), and indole-3-butyric acid (IBA). AgNPs significantly accelerated shoot induction, with primordia appearing within 10 days, compared to 2–3 weeks in other treatments. The best shoot multiplication occurred in the medium appended with 2.5 mg L⁻¹ BAP, 2.5 mg L⁻¹ ZnONPs, and 0.5 mg L⁻¹ NAA. Rooting was most effective with 2.0 mg L⁻¹ IBA, yielding an average of 11.7 roots per plantlet. The genetic fidelity of regenerated plantlets was confirmed using inter-simple sequence repeat (ISSR), start codon targeted (SCoT), and inter-primer binding site (iPBS) markers, showing 93–96% monomorphism, indicating high clonal uniformity. Comparative foliar micromorphology between the mother plant and the regenerants further confirmed phenotypic stability. Biochemical assays revealed high antioxidant activity and elevated phenolic and flavonoid contents in in vitro plantlets. Liquid chromatography-mass spectrometry (LC-MS) and total chemical constituent (TCC) analyses confirmed key bioactives such as kaempferol, ethyl cinnamate, methyl cinnamate, p-cymene, and germacrene. Overall, nanoparticle supplementation improved regeneration and preserved phytochemical integrity in K. galanga.

Micro- and nanoplastics (MNPs) serve as both intrinsic toxicants and vectors for environmental pollutants such as antibiotics, raising concerns about potential synergistic toxic effects. However, the mechanistic role of MNPs in mediating combined toxicity remains insufficiently understood. This study examines how simulated environmental aging affects the toxicity of polystyrene nanoplastics (PS-NPs), both alone and in combination with norfloxacin (NOR), in human intestinal Caco-2 cells. Aging significantly altered PS-NPs physicochemical properties, including enhanced surface oxidation, increased hydrophilicity, and reduced particle size. These changes substantially enhanced cytotoxicity: at 400 μg mL⁻¹, cell viability dropped to 50.7% for aged PS-NPs compared to 74.4% for virgin particles. Co-exposure with NOR (5 μg mL⁻¹) further exacerbated this effect. Counterintuitively, this increased toxicity did not result from improved NOR carrier capacity. Cellular NOR uptake showed no significant difference between aged and virgin PS-NPs groups, and aged PS-NPs exhibited significantly lower cellular uptake (p < 0.001) than virgin particles at 200–400 μg mL⁻¹. Mechanistic analysis revealed that intensified toxicity originates from heightened intrinsic reactivity of aged particles, leading to elevated oxidative stress (higher ROS levels at 400 μg mL⁻¹) and enhanced inflammatory responses (increased TNF-α release). At high concentrations, the dominant intrinsic toxicity of aged PS-NPs masked synergistic effects with NOR. In summary, environmental aging critically amplifies nanoplastics hazards by enhancing their intrinsic toxicity rather than carrier capacity, emphasizing the urgent need to revise risk assessment frameworks to account for aging-induced changes in plastic pollution.

An improved solvothermal-synthesized 2D Fe-MOF (S-BUC-21(Fe)) achieves rapid photocatalytic reduction of Cr(VI) to Cr(III) within 6 min using tartaric acid under UV light and sunlight. The material enables continuous-flow wastewater treatment (100% efficiency for 10 h) and demonstrates ecological safety via Chlorella growth assays.