Environmental Science: Nano最新文献

Plant uptake of micro- and nanoplastics can lead to contamination of food with plastic particles and subsequent human consumption of plastics. There is evidence that plant roots can take up micro and nanoplastics; however, most of this evidence stems from experiments conducted with plants grown in hydroponics or agar systems where uptake of nanoparticles by roots is more favorable than when plants were grown in soil. Here, we discern the root uptake and accumulation of polystyrene nanospheres in plants grown in different growth media: agar, hydroponics, and soil. In addition, we tested the impacts of nanospheres on plant biomass and plant stress. Wheat and Arabidopsis thaliana were grown in agar, hydroponics, and soil media and exposed to polystyrene nanospheres. Three different nanospheres were used (40 nm and 200 nm carboxylate-modified and 200 nm amino-modified polystyrene) and uniformly mixed into the growth media. Plants were grown for 7 to 10 days and the roots were then examined for the presence of nanospheres by confocal laser scanning microscopy and scanning electron microscopy. Plant stress was evaluated by measuring reactive oxygen species (ROS). We observed the 40 nm nanospheres inside the plant roots, but the 200 nm nanospheres only adhered to the root cap cells showing no uptake into the roots. Furthermore, confocal images indicated that root uptake of nanospheres was favored in hydroponic solutions as compared to agar and soil media. Plant biomass was generally not affected by the nanospheres, except for hydroponically grown Arabidopsis thaliana, where biomass was significantly reduced. Small sized (40 nm) and positively charged (200 nm amino-modified) nanospheres showed higher ROS accumulation in plants than negatively charged 200 nm carboxylate-modified nanospheres. This study provides evidence that polystyrene nanospheres can be taken up into the interior of plant roots and cause plant stress, but these impacts are less pronounced in media where the plastic particles are less mobile, like in agar and soil media as compared to hydroponic systems.

The presence of persistent organic pollutants (POPs) and emerging contaminants (ECs) in the environment is a global concern due to their widespread use and resistance to degradation, further exacerbated by their tendency to accumulate in living organisms. Addressing the need to mitigate the harmful and cumulative impacts of pollution in the environment requires the development of effective and sustainable techniques for reducing these xenobiotics. Nanobiotechnology is an interdisciplinary field that combines nanotechnology and biotechnology to mitigate these environmental challenges, offering innovative solutions. Among them, nanomaterial-assisted bioremediation or nanobioremediation stands out as a promising alternative due to its versatility in combining properties that enable the development of customized remediation systems tailored to specific needs. This feasibility stems from the metabolic diversity and adaptability of microbial enzymatic machinery for the degradation of organic compounds, synergized with the extensive properties offered by nanoscale materials. This study provides an overview of nanobiotechnological systems developed to address halogenated POPs and emerging contaminants derived from pharmaceutical and personal care products (PPCPs). It discusses their methods of application, effectiveness, and the synergies resulting from the combination of nanomaterials and microorganisms, as well as some of their interaction mechanisms. Additionally, it emphasizes the importance of utilizing clays as a source of potentially modifiable natural nanomaterials with excellent properties for the development of sustainable hybrid remediation systems. Finally, the prospects and needs in this field of research are discussed.

Surfactant-based treatment, particularly Pickering emulsion-based treatment, is becoming an attractive technique to remediate the globally concerning petroleum hydrocarbon-related soil pollution. Cellulose nanocrystals (CNCs) are promising natural materials to enhance the stability and performance of Pickering emulsions. In this study, rice straw was hydrolyzed through sulfuric acid (SCNCs) and combined HCOOH/H₂SO₄ (FSCNCs) to prepare CNCs, respectively. The yield of FSCNCs (73.2%) was significantly higher than that of SCNCs (44.6%), which largely reduced the consumption of H₂SO₄. Notably, the as-prepared FSCNCs had a smaller particle size and more hydrophobic formyl groups than the SCNCs, enabling FSCNCs to exhibit better emulsification, stability, and amphiphilicity. The Pickering emulsions stabilized by FSCNCs were able to remove up to 59.1% of tetradecane, which was used as a representative molecule of petroleum hydrocarbons from soils across a wide range of ambient temperatures and ionic strengths. In the presence of surfactants, such as Tween-80 and a plant biosurfactant, the droplet size decreased distinctly, further promoting the removal efficiency of tetradecane from soil. The large amount of oxygen-containing groups in FSCNCs favored the electrostatic attractions between FSCNCs and the minerals or metals in soils. The superior emulsification effect of FSCNCs greatly promoted the transfer of tetradecane into the aqueous phase, thus enhancing the remediation efficiency. The findings provide novel insights into the utilization of Pickering emulsions stabilized by FSCNCs in remediation of soils contaminated by petroleum hydrocarbons.

Current methods for producing gold nanoparticles (AuNPs) typically involve solutions containing 50 to 27 000 ppm of gold. These precursor solutions are derived from purified ore material and are not representative of waste-derived gold-containing solutions, which generally range from 20 to 30 ppm. Electronic waste (e-waste) is an increasing global concern due to the presence of various toxic substances that can leach into the environment and pose risks to human health. However, e-waste also represents a rich source of precious metals, including Ag, Pd, and Au. Here, we report the synthesis of AuNPs derived from AuCl₄⁻ or AuI₄⁻ at concentrations typical of e-waste streams, as well as from printed circuit board (PCB) e-waste samples. The AuNPs, ranging from 3 to 30 nm in diameter, are deposited onto commercially available cellulose fibres by a reductive deposition method using hydrazine hydrate. The catalytic performance of the AuNPs was evaluated in the reduction of p-nitrophenol to p-aminophenol in the presence of NaBH₄. The AuNPs derived from e-waste on cellulose exhibited higher turnover number (TON) and turnover frequency (TOF) compared to commercially available 30 nm AuNPs and previously reported AuNPs on cellulose, possibly due to trace amounts of palladium present. This study demonstrates that AuNPs can be efficiently synthesised from e-waste streams and provides proof-of-concept evidence that the gold in bulk e-waste can serve as a valuable source of high-value catalysts.

In the context of deep geological disposal of nuclear wastes, this work reports the formation of vaterite colloids in aqueous mixtures of Beishan groundwater and uranyl nitrate. The thermodynamic equilibrium conditions of Beishan groundwater were altered by the presence of ternary uranyl solution species, e.g., Ca₂UO₂(CO₃)₃(aq) and CaUO₂(CO₃)₃²⁻. This led to the formation of spheroid-like vaterite colloids with a primary size of 3–4 nm and a secondary size of tens of nanometers, evidenced by synchrotron small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). Stopped-flow SAXS measurements revealed that the formation and aggregation of vaterite nanoparticles occurred in less than 100 seconds. Vaterite colloids remained stable with respect to transformation to other stable polymorphs of CaCO₃ in groundwater over the course of one year, due to the synergistic effects of UO₂²⁺, Mg²⁺, and SO₄²⁻. The presence of stable nano-sized vaterite nanoparticles with negative surface charges may increase the potential migration risks associated with U(VI). These results contribute to predicting and understanding the geochemical fate of radionuclides, as well as safety assessment of a nuclear waste repository.

Iron nanoparticles were phytosynthesized from biomass residues of two subspecies of Cannabis sativa (ssp. sativa and ssp. indica) and evaluated as a nanofertilizer for soybean growth. Both nanoparticles were identified as magnetite (Fe₃O₄) with a dry size smaller than 30 nm. The Fe₃O₄ nanoparticles (NPs) synthesized from ssp. indica (Fe NP-I) were negatively charged (−27.2 ± 0.2 mV) with a smaller hydrodynamic diameter (164 ± 47 nm) than those from ssp. sativa (Fe NP-S) (+ 4.3 ± 0.1 mV; 1739 ± 146 nm). These differences were the result of variable composition of extracts from the two subspecies used for NP synthesis. Notably, C. sativa ssp. sativa contained a higher ratio of alcohols and mercaptans, while C. sativa ssp. indica contained more amines, ketones and organic acids. The dissolution of ions from the subspecies ssp. sativa and ssp. indica was 0.28 and 0.01% after 168 hours, respectively. When foliarly applied to soybean at 200 mg L⁻¹ (6.25 ml per plant), Fe NP-S and Fe NP-I increased the content of chlorophylls by 142% and 115%, antioxidants by 121% and 124% and polyphenols by 177% and 106%, respectively, after 3 weeks of growth, compared to corresponding controls. However, Fe NP-S increased soybean biomass by 148%, whereas Fe NP-I had no impact on growth. These findings highlight the impact of the plant genotype on the characteristics and effects of biosynthesized nanoparticles and provide novel insights for plant feedstock preferences for nanoparticle synthesis from plant waste for sustainable nano-enabled agriculture.

In light of the growing use of plastics, assessing their impact on edible plants is essential for environmental preservation and food security. Researchers have employed various traditional fluorescence labeling methods to visualize nanoplastic traces in plants. However, these techniques are hindered by various limitations, such as shallow penetration depth, high background noise, and interference from autofluorescence, which compromise their accuracy and applicability in studying nanoplastic behavior in plant systems. This study utilized luminous upconverted labeled polystyrene nanoparticles (PS@NaYF₄:Yb⁺³/Er⁺³) to visualize nanoparticle uptake and accumulation in komatsuna (Brassica rapa var. perviridis) under a 980 nm near-infrared laser. Results from stereomicroscopy, scanning electron microscopy, Z-depth coding, and three-dimensional visualization confirm the accumulation of polystyrene nanoparticles (PS-NPs) in the plant, not only in the roots but also in edible parts. This accumulation led to a 33.18% reduction in fresh yield and a 19.05% reduction in dry yield. Our findings highlight that labeling PS-NPs with α-NaYF₄:Yb⁺³/Er⁺³ offers an innovative approach for studying nanoplastic uptake and translocation behavior in plants. Their high emission efficiency under near-infrared excitation and resistance to background fluorescence make them an excellent tool for tracking nanoplastics in complex biological and environmental systems, mitigating the drawbacks associated with traditional fluorescence methods.

Nanoplastics (NPs) are emerging pollutants that widely exist in wastewater treatment systems, but their potential effects and mechanism of action on aerobic denitrifying bacteria remain unclear. This study investigated the effects of different concentrations (1, 10, 20, 50, 100 mg L⁻¹) of polystyrene nanoplastics with/without amino group (PS NPs and PS-NH₂ NPs) on a typical aerobic denitrifier, Pseudomonas stutzeri (P. stutzeri). The results indicated that NPs were abundantly adsorbed on the surface of P. stutzeri, which have hindered oxygen transfer and favored denitrification. The expression of genes related to nitrogen metabolism were both downregulated under the stress of NPs. However, PS NPs promoted the nitrogen removal performance by enhancing energy metabolism and biosynthesis, notably through the upregulation of the tricarboxylic acid (TCA) cycle and ribosome pathways. In contrast, PS-NH₂ NPs impaired the sdhC involved in the TCA cycle, leading to an obstruction of cellular energy metabolism. Additionally, PS-NH₂ NPs triggered more severe membrane damage and oxidative stress, leading to a significant upregulation of genes related to EPS secretion, biofilm formation, and ROS scavenging to alleviate cellular stress. However, this did not overcome the negative effects caused by the downregulation of nitrogen metabolism, energy metabolism, and biosynthesis, resulting in a decline in the nitrogen removal performance of P. stutzeri. This study provides an understanding of the potential mechanisms underlying changes in P. stutzeri to different NPs stressors.

Polymer nanocarriers (PNCs) are designed to deliver active ingredients in pharmaceuticals, food science and agricultural applications and it is essential to ensure their safety towards environmental and human health. Most research and guidance documents on the fate and effect of nanoparticles primarily focus on metal and metal oxide nanomaterials, while nanosafety research on organic nanomaterials is still in the early stages. This review aims to address a set of critical questions that currently prevent the risk assessment of PNCs. Our focus is on the analytical challenges associated with the detection, quantification and characterisation of PNCs in environmental and biological matrices. By addressing the key questions related to the durability, degradability and biological barrier-crossing properties of PNCs, we critically assess the analytical techniques used across different sectors. Our goal is to highlight the strengths and limitations of these analytical methods for the risk assessment of PNCs and to emphasize the significant overlap in the applications of PNCs across various sectors. We also discuss the urgent need for further research to scientifically advance analytical strategies for PNCs, which are essential for supporting responsible innovation in nanotechnology, ensuring the safety of both human and environmental health.

Detection of small molecules such as phthalates is a persistent challenge in current point-of-care sensor technology for environmental applications. Here, owing to their porous crystalline lattice and tunable molecular specificity, two-dimensional metal–organic frameworks (2D MOFs) present unique opportunities as an emerging class of transducers. Addressing the challenges of efficient nanomaterial design and device prototyping based on MOFs, this work demonstrates programmable liquid-phase epitaxy (LPE) growth of a nickel(II) and 2-aminoterephthalic acid (BDC-NH₂) based 2D MOF in modular microfluidic circuits on a chip. Fully automated layer-by-layer (LbL) LPE yields homogeneous growth of crystalline 2D Ni-BDC-NH₂ or Ni-MOF of thicknesses ranging from 2 to 25 nm on the Si/SiO₂ substrate. Employing specially designed chips with metal microelectrode arrays (MEAs) as substrates, the LbL-LPE approach is successfully used to carry out scalable integration of 2D Ni-MOF sensor arrays with high reproducibility. Using electrochemical impedance spectroscopy (EIS), the sensor chips are deployed for detection of diisobutyl phthalate (DiBP), one of the plasticizers linked to serious illnesses of the endocrine system, in the concentration range from 1 to 20 μg mL⁻¹.