Microplastics (MPs) are pervasive vectors in soil, but their quantitative role in additive transport and transformation remains unclear. This study examines the release, transport, and transformation of TBBPA and BDE-209 from polystyrene MPs. Vertical MP migration forms an observed secondary emission front under hotspot-like conditions at 5-7 cm depth, which influences the spatial distribution of the strongly hydrophobic BDE-209, leading to a concentration plateau at this interface. We developed a mechanistic model based on Fick's second law, parameterized with the first-order release rate constant (krelease), colloidal diffusion coefficient (Dsc), and biodegradation rate constant (k) under our experimental conditions. This model successfully captured the distinct migration patterns of the two additives, supported by machine learning (XGB) validation within the scope. Depth and time were the primary experimental controls, while EC and pH were the key soil properties influencing additive fate. Beyond transport, MP-driven soil changes promoted extensive additive transformation into 59 byproducts. The majority of BDE-209 transformation products were predicted to exhibit significant oral toxicity and high persistence in the environment. Our findings propose a novel, comprehensive framework that advances beyond existing approaches by linking MP-mediated transport to hazardous product formation, providing essential insights for the risk assessment of plastic-contaminated soils.

SiCf/SiC ceramic matrix composites (CMCs) are prime candidates for hot-section components in next-generation aero-engines due to their exceptional high-temperature strength and low density. However, the rapid and efficient densification of components remains the critical bottleneck that severely hinders their widespread engineering applications. In this work, a rapid nano-infiltration and transient eutectic-phase (NITE) sintering method to fabricate high performance SiCf/SiC composites. By utilizing the internal Joule heating of 3D conductive carbon networks, rapid densification under low pressure was successfully achieved. The influence of sintering aid content on the microstructure and mechanical properties of the composites was investigated. SiCf/SiC composites can be densified with 12 wt% sintering aids within 10 min. The sintering aids are present at the grain boundaries in the form of an Al-Y-O amorphous phase and Y3Al5O12 crystals. The extremely short sintering time prevents damage to the fibers and the fiber interfaces, thereby enabling the fabrication of composites with favorable mechanical properties. The optimum flexural strength and fracture toughness of the SiCf/SiC composites are 411.41 ± 37.42 MPa and 13.51 ± 0.84 MPa·m1/2, respectively. This work can provide new strategies and guidance for the rapid fabrication of various ceramic matrix composites with excellent mechanical properties.

Polyborosiloxanes (PBS)-derived SiBOC ceramics have received considerable attention owing to their excellent thermal and mechanical properties. In this work, a new PBS with high ceramic yield, low viscosity and low curing temperature was synthesized by a hydrolysis sol-gel method with ethylorthosilicate (TEOS), methyl trimethoxysilane (MTMS) and diphenyl-dimethoxysilane (DMDPS) as monomers. The PBS possessed low viscosity (114.97 mPa & sdot;s), and could be cured at 120 degrees C for 12 h, which made it more advantageous as a matrix precursor to infiltrate into fibers. The SiBOC ceramics were prepared from pre-ceramic gels of PBS by pyrolyzing. The results revealed that the addition of boron suppressed the crystallization of beta-SiC and improved thermal stability, leading to a higher ceramic yield of 79.39 % at a B/Si ratio of 0.1. SiBOC ceramic had a relatively dense morphology at 1700 degrees C. In addition, carbon fiber reinforced SiBOC ceramic matrix composites (Cf/SiBOC CMCs) were fabricated using PBS as the matrix resin and carbon fiber as the reinforcement. The Cf/SiBOC CMCs owned a flexural strength of 135 MPa after three PIP cycles, higher than the Cf/SiOC CMCs. As a new precursor, the PBS contain methyl phenyl group has great potential application in the field of fiber reinforced ceramic matrix composites.

This perspective addresses the critical issue of soil pollution, exacerbated by rapid urbanization, intensive agriculture, and climate change, which introduces a complex mix of contaminants such as heavy metals, pesticides, per- and polyfluoroalkyl substances, and microplastics into the soil. These pollutants pose severe risks to environmental health and agricultural productivity by altering soil functionality and contaminant mobility. This perspective summarizes innovative monitoring and remediation technologies, including advanced sensors and bioremediation strategies, that enable real-time detection and effective management of soil pollutants. The integration of artificial intelligence and machine learning offers significant advancements in predicting and managing soil contamination dynamics. Furthermore, the perspective discusses the challenges and future directions in soil pollution research, particularly the need for robust policy frameworks and international cooperation to effectively manage and mitigate soil contamination. Emphasizing a multidisciplinary approach, this study calls for enhanced global standards, public engagement, and continued scientific research to develop sustainable solutions for soil remediation and to ensure the protection of vital soil resources for future generations.

Caffeine in aquatic ecosystems is an emerging contaminant causing significant environmental concern. In this work, spent coffee ground (SCG) was pyrolyzed at 300, 450, and 600 °C to produce pristine SCG biochars (CG), which were then ball-milled to produce ball-milled SCG biochars (BMCG). A batch experiment with ball-milled and pristine biochars showed that ball-milled biochars pyrolyzed at 450 °C and 600 °C had the highest capacities to adsorb caffeine. Subsequently, ball-milled CG450 (BMCG450) was selected for further analysis. The results showed that ball milling dramatically augmented the specific surface area and oxygen-containing functional groups of the biochar. The Langmuir maximum caffeine adsorption capacity was 82.65 mg/g. Both solution pH and ionic strength affected caffeine removal by BMCG450. As pH increased, increased electrostatic repulsion limited caffeine adsorption onto the biochar. However, an increase in ion strength slightly enhanced caffeine adsorption because of the electrostatic screening effect of cations. The ball-milled SCG biochar also showed high adsorption efficiency in a completely mixed flow reactor under continuous flow conditions. Our study indicates that ball-milled SCG biochar at 450 °C can serve as a viable sorbent for the removal of caffeine from water.

Continuous SiC fiber-reinforced SiC ceramic matrix composites (SiCf/SiC CMCs) are well-known high temperature thermal structural materials. However, the performance degradation under high-temperature oxidation remains a critical challenge. In this study, SiCf/SiC ceramic matrix composites containing ZrB2 and TiB2 with excellent oxidation resistance at 1500 degrees C were fabricated via the nano-infiltration and transient eutectic (NITE) process. The results revealed that the optimal flexural strength and fracture toughness, reaching 499.47 f 32.44 MPa and 10.01 f 0.61 MPa m1/2, respectively. The synergistic effect of Y2Ti2O7, ZrSiO4, and SiO2 in the continuous, dense oxide layer formed after 1500 degrees C oxidation effectively impeded oxygen penetration into the matrix, significantly enhancing the high-temperature oxidation resistance of the composite material. The retention rates of flexural strength and fracture toughness after oxidation of 15 h were 63.72 % and 62.31 %, respectively. This work elucidates the mechanisms of borides enhance SiC composites' mechanical and oxidation properties, providing theoretical basis for extreme-environment applications.

As an emerging pollutant, caffeine has increasingly attracted public attention. Although typically metabolized in the human body, approximately 5% of ingested caffeine is excreted through urine, ending in wastewater treatment plants (WWTPs). Given the extensive global consumer market, the daily quantity of caffeine reaching these WWTPs is significant. Understanding the fate of caffeine through the three treatment stages in WWTPs is thus crucial. The primary treatment stage, mainly focused on removing large solids and grit from wastewater, does not effectively and directly eliminate caffeine from the sewage. Conversely, the secondary treatment stage plays a central role in caffeine removal, heavily depending on microbiological activities under aerobic, anaerobic and anoxic conditions. Tertiary treatment procedures such as adsorption, advanced oxidation processes, membrane separation and constructed wetlands can further remove caffeine before the safe discharge of effluent into the environment. This review concludes that the caffeine removal capacities can vary significantly across different WWTPs due to differences in treatment methods, cost-efficiency and operational constraints. Hence, there is an ongoing need for continued research and optimization of wastewater treatment processes concerning caffeine and similar emerging pollutants.

In order to improve the high-temperature resistance and thermal insulation of SiC nanofiber aerogel, the structural design and preparation of SiC nanofiber composite aerogel felt were carried out based on the heat transfer mechanism. A novel multi-layer SiC nanofiber aerogel felt was prepared with the ablative layer (ZrO2/ ZrSiO4 anti-oxidation layer), opacifiers layer (TiO2 and SiC), and heat insulation layer (SiC nanowire aerogel). Compared with the single SiC nanowire aerogel, the oxidation resistance temperature of SiC nanofiber composite aerogel felt increased from 1300 degrees C to 1500 degrees C during aerobic calcination. With the butane gun ablation, the back temperature of the single SiC nanofiber aerogel felt was 308 degrees C, while the back temperature of the composite aerogel felt was only 130 degrees C. The structural design of the multi-layer SiC nanofiber composite aerogel felt provides an approach to improving thermal insulation properties in extreme environments.

Biodegradation technology offers a sustainable approach to contaminant remediation, specifically targeting antibiotics to mitigate their ecological impact. While biological graphene hydrogel (BGH) as a biocarrier has demonstrated efficacy in contaminant biodegradation, its current performance requires enhancement. Sustainable bioaugmentation strategies offer a promising approach; however, their optimization necessitates a deeper mechanistic understanding of bioaugmented bio-graphene complexes and their associated contaminant degradation pathways. Thus, this study employed a Pseudomonas bioaugmentation strategy to construct a functionally enhanced microbial-graphene composite hydrogel system (MC+Pseu-BGH). The system was evaluated for its ability to degrade sulfamethoxazole (SMX) and chloramphenicol (CAP), two common antibiotics used in aquaculture. Pseudomonas augmentation significantly enhanced CAP (99.89 % in 24 h) and SMX (94.7 % in 120 h) removal in the MC+Pseu-BGH system, compared to 87.36 % (CAP) and 87.12 % (SMX) in the non-augmented control system under identical conditions. It boosted efficiency by reducing GO, optimizing the hydrogel's conductivity/structure (increased spacing/defects) to improve electron transfer. Pseudomonas also modulated biofilm extracellular polymeric substances (EPS) secretion, enriched key genera (Acidaminobacter, Desulfovibrio), and upregulated microbial enzymes (e.g., nitroreductase, amidohydrolase). This material-microbe synergy facilitated degradation pathways: CAP degradation proceeds via nitro-reduction, acetylation, and amide hydrolysis; SMX degradation occurs via S-N and N-O bond cleavage. Synergistic interactions within the conductive hydrogel microenvironment drove the accelerated degradation. This work elucidates the synergistic mechanism of bioaugmented graphene hydrogel-mediated antibiotic degradation, offering a novel technological approach for efficient antibiotic wastewater treatment.

Biochar, a porous carbonaceous material produced from biomass pyrolysis under limited oxygen, has emerged as a promising material for environmental remediation due to its stability, adsorption capacity, and potential for carbon sequestration. Though raw or unmodified biochar often exhibits limited surface functionality, low surface area, and poor affinity for specific contaminants, its effectiveness in practical applications is restricted. Various modification techniques have been developed to address these limitations, including physical activation, chemical functionalization, and surface doping with metals. Among these, iron-modified biochar (Fe-BC) has attracted considerable attention due to the unique redox properties of iron and its strong binding affinity for anions and organic pollutants. Fe-BC is typically synthesized through impregnation, co-pyrolysis with iron salts, or post-pyrolysis treatment. These modifications enhance the surface area and porosity and introduce reactive sites that significantly improve the sorption of phosphate, arsenic, heavy metals, and dyes from wastewater, as well as facilitate catalytic reactions such as Fenton-like oxidation. Recent studies have demonstrated the multifunctionality of Fe-BC in wastewater treatment and soil remediation, as well as in agriculture as a slow-release nutrient carrier. Moreover, novel synthesis approaches using green chemistry principles and low-cost iron precursors have made Fe-BC more sustainable and scalable. Despite its potential, challenges remain regarding the long-term stability of leaching iron, regeneration, and environmental risks. This review provides a comprehensive analysis of current modification strategies for biochar with a focused evaluation of Fe-BC, including synthesis methods, physicochemical properties, contaminant removal mechanisms, and practical applications. Future perspectives are discussed to guide research toward optimizing Fe-BC for the circular economy and sustainable environmental technologies.

The application of nano-enabled agricultural chemicals introduces metal oxide nanoparticles (NPs) into agricultural soils, with CuO-NPs as one of the most common. Because CuO-NPs can dissolve to release Cu ions, they often display different environmental impacts. As such, it is essential to comprehensively examine the Cu bioavailability of CuO-NPs in soil and its impacts on soil enzyme activities, which are critical for soil health. This research examined how variations in CuO-NP size (10, 40, and 80 nm), surface coatings (polyvinylpyrrolidone and polyacrylic acid), and concentrations (100, 250, and 500 mg/kg) influenced the extractable Cu in soil and their impacts on selected soil enzymes (acid phosphatase and dehydrogenase). Main indicators were quantified after a 30-day incubation period. The bioactive Cu related to CuO-NPs as determined via CaCl2 and DTPA extractions indicated that 10 nm CuO-NPs had the highest extractable Cu across all incubation times. Besides, polyvinylpyrrolidone and polyacrylic acid coating had little impact on extractable Cu compared to uncoated ones. Unlike CuSO4, extractable Cu concentrations in CuO-NPs spiked soil increased over time. CuO-NPs dissolution was negatively correlated with soil pH. CuO-NPs after 24 h short-term exposure significantly inhibited both enzyme activities across all tested concentrations, with smaller NPs showing greater effect. However, reduced toxicity to enzyme activities was observed after 30 days. A strong negative correlation was observed between CuO dissolution and enzyme activities after 1 and 30 days, indicating Cu ions are the main toxicity source. This study elucidates that CuO-NP size, concentration, surface coating, and exposure duration collectively impact the interactions of CuO-NPs with soil enzymes, providing critical insights into the sustainable use of nanotechnology in agriculture.

Arsenic (As) contamination of rice grain poses a serious threat to human health. Therefore, it is crucial to reduce the bioavailability of As in the soil and its accumulation in rice grains to ensure the safety of food and human health. In this study, mango (Mangifera indica) leaf-derived biochars (MBC) were synthesized and modified with iron (Fe) to produce FeMBC. In this study, 0.5 and 1

Biochar (BC) can be coated with microbial extracellular polymeric materials (EPS) to form BC-EPS corona in an aqueous environment, which may significantly alter its ecological toxicity caused by EPS-facilitated accumulation of environmental contaminants. This work examined the EPS corona formation on the surface of shrub branch BC and wheat straw BC, pyrolyzed at 450 °C and 650 °C, and evaluated its effect on the sorption of divalent metals Cd2+, Pb2+, Cu2+, and Ni2+. In single metal systems, the formation of a BC-EPS corona shows little enhancement on Cd2+ and Cu2+ accumulation, but significantly elevated Ni2+ and Pb2+ adsorption: Ni2+ sorption increased from 20 mg/g for pristine BCs to 30 mg/g, Pb2+ sorption increased from below 25 mg/g to above 90 mg/g. In multiple metal systems, the binding distribution of Pb2+ and Cu2+ on BC-EPS corona appeared to be more extensive compared to that of Cd2+ and Ni2+. The toxicity of BC-EPS increased by about 2 to 3 times in aquatic organisms compared to pristine BC, attributed to the higher accumulation of heavy metals in BC-EPS corona. In summary, BC-EPS corona enhanced BC’s sorption capacity for metals, especially for Pb2+ and Ni2+, thus elevating the BC’s ecological risks owing extra amount of pollution loading.

Herein, hydrogen (H & BULL;) radical was observed as a new pathway to produce hydroxyl (OH & BULL;) radicals that promoted cadmium sulfide (CdS) dissolution and thus Cd solubility in paddy soils. In soil incubation experiments, the bioavailable Cd concentrations in flooded paddy soils were increased by 8.44 % as the soil was aerated for 3d. For the first time, the H & BULL; radical was observed in aerated soil sludge. The association of CdS dissolution with free radicals was thereafter confirmed in an electrolysis experiment. Both H & BULL; and OH & BULL; radicals in electrolyzed water were confirmed by the electron paramagnetic resonance analysis. In the system with CdS, water electrolysis increased soluble Cd2+ concentration by 60.92 times, which was compromised by 43.2 % when the radical scavenger was introduced. This confirmed the free radicals can lead to oxidative dissolution of CdS. The H & BULL; radical was generated in systems with fulvic acid or catechol irradiated by ultraviolet lights, indicating soil organic carbon could be an important precursor for H & BULL; and OH & BULL; radicals. Biochar application decreased soil DTPA-Cd by 22-56 % invoking mechanisms besides adsorption. First, biochar quenched radicals and reduced CdS dissolution by 23.6 % in electrolyzed water in which-C-OH of biochar was oxidized to C_O. Second, biochar boosted Fe/S-reducing bacteria and thus compromised CdS dissolution, as affirmed by a reversal correlation between soil available Fe2+ and DTPA-Cd concentrations. A similar phenomenon occurred in Shewanella oneidensis MR-1-inoculated soils. This study provided new insights into the bioavailability of Cd and offered feasible measures to remediate Cd-contaminated paddy soils with biochars.

Phosphorus (P) as an essential nutrient for life sustains the productivity of food systems; yet misdirected P often accumulates in wastewater and triggers water eutrophication if not properly treated. Although technologies have been developed to remove P, little attention has been paid to the recovery of P from wastewater. This work provides a comprehensive review of the state-of-the-art P removal technologies in the science of wastewater treatment. Our analyses focus on the mechanisms, removal efficiencies, and recovery potential of four typical water and wastewater treatment processes including precipitation, biological treatment, membrane separation, and adsorption. The design principles, feasibility, operation parameters, and pros & cons of these technologies are analyzed and compared. Perspectives and future research of P removal and recovery are also proposed in the context of paradigm shift to sustainable water treatment technology.

Hydrochars formed by hydrothermal carbonization of hickory wood, bamboo, and wheat straw at 200 °C were modified by potassium permanganate (KMnO4) for the sorption of Pb(II), Cd(II), and Cu(II). The wheat straw hydrochar (WSHyC) modified with 0.2 M KMnO4 resulted in the most promising adsorbent (WSHyC-0.2KMnO4). Characterization of WSHyC and WSHyC-0.2KMnO4 revealed that the modified hydrochar features large specific surface area, rich of surface oxygenic functional groups (OCFG), and a significant amount of MnOx micro-particles. Batch adsorption experiments indicated that the adsorption rate by WSHyC-0.2KMnO4 was faster than for WSHyC, attaining equilibrium after around 5 h. The optimum adsorption capacity (Langmuir) of Pb(II), Cd(II), and Cu(II) by WSHyC-0.2KMnO4 was 189.24, 29.06 and 32.68 mg/g, respectively, 12 ∼ 17 times greater than by WSHyC. The significantly enhanced heavy metal adsorption can be attributable to the increased OCFG and MnOx microparticles on the surface, thereby promoting ion exchange, electrostatic interactions, and complexation mechanisms.