Hazardous By-products Research Articles

Noble-Metal-Free Electrocatalysts for Selective Hydrogen Peroxide Generation via Oxygen Reduction Reaction.

Hydrogen peroxide (H2O2) is a versatile chemical widely used in various industries. The traditional anthraquinone method for H2O2 synthesis has environmental and safety concerns due to the use of organic solvents and hazardous by-products. The direct synthesis of H2O2 from H2 and O2 poses risks of flammability and explosion. Recently, the 2-electron oxygen reduction reaction (2e- ORR) method has emerged as a promising alternative, offering safety, environmental friendliness, and cost-effectiveness. This method utilizes gas diffusion electrodes to efficiently generate H2O2 without the need for additional dilution. In this review, we focus on the recent advancements in noble-metal-free materials for 2e- ORR electrocatalysis, which play a crucial role in the efficient production of H2O2. These materials, including transition metal compounds, macrocyclic complexes, carbon-based catalysts, framework materials, and MXenes catalysts, demonstrate significant advantages in enhancing H2O2 yield. The development of these non-precious metal catalysts can reduce costs and improve sustainability and promote the commercialization of related technologies. The review concludes with an outlook on the future trends of 2e- ORR electrocatalysts.

Advances on jarosite residue detoxification and reutilization: a review.

Jarosite residues are typical hazardous waste byproducts generated during the iron removal process in hydrometallurgical solutions. The jarosite process is widely used for iron removal in zinc hydrometallurgy; jarosite disposal has become a significant barrier to sustainable development in the industry. During this process, jarosite residues entrain and co-precipitate with heavy metals, which are hazardous but valuable. To better understand jarosite residue pollution control and circular recycling, we reviewed related research conducted over the past two decades, analyzed their characteristics, discussed state-of-the-art technologies for jarosite residue detoxification and reutilization, and proposed feasible suggestions for jarosite circular reutilization. We hope that this review helps solve the problem of jarosite residues and promote the sustainable development of the zinc hydrometallurgical industry.

Microbial and Enzymatic Biodegradation of Plastic Waste for a Circular Economy

Plastics play a crucial role in modern life, but their accumulation poses a serious threat to both the environment and human health. Due to their effects on the terrestrial and aquatic environment, it is essential to develop sustainable approaches to dispose of waste plastics. Traditional methods of plastic disposal, such as burning and landfilling, are problematic since they produce hazardous byproducts. Biodegradation is a potentially effective, eco-friendly approach which uses microbial consortia or isolated enzymes to break down plastic waste. Enzymes interact with plastic surfaces and hydrolyse the large polymer chains into smaller units. These byproducts can then be utilised as carbon sources by microbes, which are eventually converted into CO2 and water. This review explores the principal approaches to plastic degradation, with a focus on existing and emerging polymers made to be readily biodegradable. In addition, sustainable valorisation methods for converting plastic waste into valuable byproducts are considered. The implementation of a circular plastic economy is expected to lead to further development, including scaling up of efficient plastic bio-upcycling processes, which can serve to stimulate environmental waste removal and value-added use of post-consumer plastic streams.

Synthesis of Palladium Nanoparticles by Electrode-Respiring Geobacter sulfurreducens Biofilms.

Electroactive microorganisms such as Geobacter sulfurreducens can couple organic electron donor oxidation to the respiration of electrode surfaces, colonizing them in the process. These microbes can also reduce soluble metal ions, such as soluble Pd, resulting in metallic nanoparticle (NP) synthesis. Such NPs are valuable catalysts for industrially relevant chemical production; however, their chemical and solid-state syntheses are often energy-intensive and result in hazardous byproducts. Utilizing electroactive microbes for precious metal NP synthesis has the advantage of operating under more sustainable conditions. By combining G. sulfurreducens's ability to colonize electrodes and synthesize NPs, we performed electrode cultivation ahead of biogenic Pd NP synthesis for the self-assembled fabrication of a cell-Pd biomaterial. G. sulfurreducens biofilms were grown in electrochemical reactors with added soluble Pd, and electrochemistry, spectroscopy, and electron microscopy were used to confirm (1) metabolic current production before and after Pd addition, (2) simultaneous electrode respiration and soluble Pd reduction over time, and (3) biofilm-localized Pd NP synthesis. Utilizing electroactive microbes for the controlled synthesis of NPs can enable the self-assembly of novel cell-nanoparticle biomaterials with unique electron transport and catalytic properties.

Highly Efficient and One-pot New Betti Bases: PEG-400 and Al2O3 Mediated Synthesis, Optimizations, and Cytotoxic Studies

Background: Multicomponent reactions (MCRs) have proven as one of the best alternatives to minimize several environmental consequences, mainly the use of hazardous chemicals, byproducts, and severe production processes. Literature reveals that MCRs with PEG-400 and metal oxide-based greener media provide a new and useful strategy for the construction of biologically potent organic systems. Objective: The present study aimed to synthesize newer Betti bases by a modified Betti reaction employing a highly efficient catalyst for the direct synthesis of a novel class of non-racemic amino benzyl naphthol ligands under green solvent media. The involvement of the articulated framework (4a-4j) was studied against nine cancer panels (NCI-60 cell lines) in terms of inhibiting/killing cancer cells. Methods: For the modification of the Betti reaction, we used 2-aminopyridin-3-ol, aromatic aldehydes, and a naphthol system using greener media employing PEG-400 and alumina as a prime active and highly selective catalyst. Furthermore, the antiproliferative activity against NCI-60 human cancer cell lines (GI50) was used for the development of pharmacologically active compounds and exhibited the single dose (10-5 M) study. Results: Based on greener media synthesis, recompenses of ease of workup, less reaction time, higher yield, and higher atom economy, as well as environmentally friendly, were reported. Betti bases were obtained at a yield of 87-98% and characterized by spectroscopic techniques. Among the synthesized scaffolds, compound 4b was found to be extra potent in melanoma cancer [MDAMB- 435], while compound 4h showed promising inhibition in leukemic cancer cell lines [HL- 60(TB) and MOLT-4]. Conclusion: A straightforward way for an efficient synthesis of Betti bases was developed via the reaction of naphthol and aldehydes with amines in PEG-400 media. An Al2O3 was effectively catalyzed in the Betti reaction in excellent yields without the formation of any other by-product in atom economy and environmentally benign way. The newly synthesized hybrids were tested in vitro against a panel of cancer cell lines, and some of the compounds exhibited significant inhibitory anti-proliferative effects. The most potent compounds (4b and 4h) showed interesting results, and compound 4b was found extra potent in melanoma cancer cell lines with -62% GI values.

Influence of elevated temperature and oxygen on the capture of radioactive iodine by silver functionalized silica aerogel

Reprocessing is considered a competent strategy for spent nuclear fuel management, yet radioiodine (129I) is emitted in reprocessing off-gas as a hazardous byproduct. Silver functionalized silica aerogel (Ag0-aerogel), a promising iodine capture material, experiences a reduction in its capacity after prolonged exposure to off-gas components at elevated temperatures, a phenomenon termed as aging. To fully understand this process, we isolated the contribution of each aging factor, exposing Ag0-aerogel samples to N2 and dry air gas streams, respectively, at 150 °C for different time periods. Aged samples were loaded with I2 to examine the capacity change and comprehensively characterized to investigate the evolution of their properties. Results show that temperature alone did not alter Ag0-aerogel's capacity but triggered Ag0 nanoparticles sintering and generated organic sulfur species. The presence of O2 reduced the capacity by ∼20 %, causing (i) formation of silver sulfide (Ag2S) crystals and (ii) oxidation of Ag-thiolate (Ag-S-r) to Ag sulfonate (Ag-SO3-r). Given that Ag2S readily adsorbs I2, the formation of Ag-SO3-r is the major inhibitor for iodine adsorption. This hypothesis was supported by density functional theory (DFT) simulations. These findings unraveled key mechanisms of Ag0-aerogel aging, which are useful in the development of materials that withstand realistic spent-nuclear-fuel-reprocessing off-gas conditions.

Experimentation on Sargassum wightii as a flash powder igniter for attaining eco-friendly combustion on pyrotechnics

Firecrackers are a vital element of cultural festivities that happen worldwide. However, the hazardous by-products they emit have a significant impact on environmental pollution, leading to the greenhouse effect and climate change. Aluminium powder serves as the fuel in the traditional flash powder mixture, nitrate of potassium serves as an oxidizing agent, and sulphur acts as the igniter at exact concentrations. The presence of sulfur in the flash powder mixture is critical as it acts as an igniter, contributing to the formation of sulfur dioxide, which can cause environmental harm. We carried out an experiment employing Sargassum wightii brown seaweed powder as a replacement for sulphur at specific amounts to lessen the effects of sulphur in flash powder. We discovered that Sargassum wightii brown seaweed powder may replace up to 50% of the sulphur significance in the flash powder mixture without impairing the flash powder's traditional performance. Our experiments included impact and friction sensitivity, SEM, and FTIR analyses to evaluate the improved flash powder composition. The results revealed that the modified flash powder mixture SP5 and SP10 emits less emission by 12% and 21%, and produces similar noise performance of 108 and 107 dB(A) to the normal flash powder composition (SP), affirming that the SP10 flash powder is a viable alternative. Moreover, in our relentless pursuit to mitigate the detrimental effects on our environment, we have ingeniously introduced a novel product—the Chinese cracker made from vegetable waste paper. Not only does this innovative solution address concerns regarding land pollution, but it also presents a sustainable approach to consumer goods.

Adsorption of eco-friendly insulating gas C4F7N on PdSe2 monolayer surface: A first-principles study

Heptafluoro-isobutyronitrile (C4F7N) is a novel environmentally friendly insulating and arc extinguishing gas utilized as a replacement for SF6 in gas insulated equipment (GIE). Nevertheless, the potentially hazardous decomposition byproducts of C4F7N resulting from sudden equipment failure may jeopardize the normal operation of GIE and the physical well-being of the operator. In this paper, using the first principles study the adsorption behavior of four common C4F7N decomposition gases (CF4, COF2, CF3CN, C2F5CN) on PdSe2 monolayer, and explore the adsorption mechanism of PdSe2 monolayer on C4F7N decomposition gas. The results show that the PdSe2 monolayer interacts with the four decomposition gases by physical adsorption mechanism, in which the PdSe2 monolayer causes the largest change in electronic properties and maximum work function (0.15 eV) near the Fermi level before and after adsorption of C2F5CN, indicating a strong interaction between C2F5CN and PdSe2 monolayer. The sensitivity of PdSe2 monolayer to C2F5CN was up to 68.61 %. Therefore, PdSe2 monolayer has the potential of selective detection of C2F5CN gas sensing materials, and the findings in this paper provide theoretical guidance for the development of PdSe2 monolayer gas sensing sensors for monitoring C4F7N insulation equipment.

Prominent differences in the adsorption and substitution characteristics of As(III) and As(V) on gypsum during wet flue gas desulfurization

Arsenic-bearing gypsum (ABG) is a hazardous by-product of wet flue gas desulfurization (FGD) and must be strictly controlled. This study investigated the migration of arsenic species during wet FGD and proposed strategies to reduce the toxicity of FGD gypsum in operation. During gypsum crystallization, the adsorption and substitution characteristics of As(III) and As(V) exhibit significant differences. The amount of As(III) captured by CaSO4·2H2O is greater than that of As(V). The As(III) adsorbed on the growth surface of CaSO4·2H2O can be incorporated into the gypsum by substituting for SO42−, while As(V) tends to remain adsorbed on the surface. Moreover, the arsenic adsorption capacity of the incompletely oxidized product CaSO3·0.5H2O was almost three times that of CaSO4·2H2O, especially for As(III). Based on the differences in the migration characteristics of As(III) and As(V), a strategy was proposed to reduce the arsenic content and biotoxicity in gypsum during operation by enhancing the oxidation of sulfite and highly toxic arsenite, thus ensuring the safe utilization of FGD gypsum.

Advanced pyro-/piezoelectric catalytic disinfection of water via porous spontaneously polarized ceramic with strong local electric field induced by micro-nano bubbles

In-situ electroporation disinfection technology inactivates microorganisms by local electric field penetrating antioxidant membranes without producing by-products, which reduces the consumption of oxidants. However, this individual technology exhibits weak disinfection performance for high water fluxes. Herein, a disinfection system based on the synergy of porous spontaneously polarized ceramic (PSPC) and micro-nano bubbles (MNB) (PSPC/MNB disinfection system, PMDS) was constructed for efficient disinfection of drinking water. Pyro-/piezoelectric effects of PSPC induced by MNB collapse constructed a 1.92 × 108 V/m of local electric field (simulated by COMSOL Multiphysics) and generated reactive oxygen species (ROS; •OH, 1O2, •O2−, and H2O2), resulting in electroporation damage on microorganisms and subsequent fatal oxidation of the intracellular contents by ROS. PMDS completely inactivated 107 CFU/mL of E. coli within 45 min, about 10 times faster than the MNB process, which is attributed to that the abundant porous and rough surface in PSPC increased the specific surface area and dipoles for pyro-/piezoelectric catalysis. Moreover, MNB collapse enriched •OH and induced pyro-/piezoelectric effects of PSPC through local temperature and pressure gradients. Synergistic interaction of PSPC/MNB collected additional thermal and mechanical energies besides the collapse of MNB, and the pyro-/piezoelectricity-induced in-situ electroporation–ROS deep oxidation avoided oxidant consumption and hazardous by-products. PMDS presented favorable disinfection efficiency in actual drinking water source, expected to be a practical system for eliminating microbial hazards in drinking water.

Trihalomethanes in chlorinated drinking water: Seasonal variations and health risk assessment in southern Iran

Assessing the adverse impacts of trihalomethanes, the most hazardous disinfection by-products, is crucial for community health protection. This study evaluated physicochemical parameters, trihalomethane levels, their prediction, and risk assessment using probability and Sobol analysis. Results indicated that electrical conductivity, total dissolved solids, nitrate, sulfate, calcium, lithium, total organic carbon, and ammonium exceeded permissible limits. Tribromomethane (0.14–3.21 μg/L in winter; 0.06–0.17 μg/L in summer), trichloromethane (1.90–3.53 μg/L in winter; 3.19–5.44 μg/L in summer), bromodichloromethane (0.62–4.24 μg/L in winter; 3.27–6.41 μg/L in summer), and dibromochloromethane (0.82–2.41 μg/L in winter; 0.69–3.03 μg/L in summer) remained within safe limits. Random Forest analysis identified total organic carbon as the most significant factor in trihalomethane production, with a positive correlation between trihalomethanes and bromide. Per the World Health Organization's risk assessment, trihalomethane concentrations posed no harm to residents (IWHO<1). However, the United States Environmental Protection Agency's assessment indicated an acceptable low cancer risk (100% cumulative cancer risk for all groups). Additionally, nitrate and fluoride levels surpassed the standard limit, with hazard index above 1 in both seasons for residents. Monte Carlo simulations showed that the 95th percentile of residents faced non-carcinogenic (nitrate and fluoride). However, 100% of children and 99.98% of adults were exposed to an acceptable low carcinogenic risk for THMs. Factors like inhalation rate, body weight, and trihalomethane levels significantly impacted health risk. These findings highlight the necessity for continuous monitoring and effective water treatment to safeguard public health, promote clean water, and advance sustainable development, advocating for sustainable water management to tackle health risks from environmental pollutants like disinfection by-products.

Experimental investigation and Monte Carlo simulation of landfill leachate treatment using physicochemical method and a non-thermal plasma reactor

ABSTRACT Leachate treatment is one of the challenging subjects in the field of waste management. Leachate as a dumpling sites hazardous byproduct due to the high concentration of chemical oxygen demand (COD) and toxic compounds with dark colour is a potential pollutant of the environment, causing a lot of problems in the absence of treatment and direct discharge to the environment. In this study, the combinatory performance of sequential chemical flocculation and coagulation process and non-thermal plasma (NTP) technology on leachate from the Sarāvān city former controlled landfill, Iran, was investigated. The outcomes of Jar test illustrated that hydrated aluminium sulphate (PAC) was selected the best coagulant compared with hydrated aluminium sulphate (HAS) and ferric chloride (FC) to remove suspended solids and colour. The optimised parameters for 10% PAC pre-treatment were obtained 3 g lime and cationic 0.1 g polyelectrolyte per 1 litre of leachate. After pre-treatment by using jar test, NTP was used to remove turbidity, colour, COD and so forth. The sequential system-based all stages of pretreatment and NTP diminished the turbidity and colour removal to 98.6% and 99.2%, respectively. Furthermore, COD, BOD5, TSS, and TDS were also reduced. As a result, combination of pre-treatment and NTP technology are able to remove the landfill leachate effectively. Monte Carlo calculations exhibited that Al3+ and H2O2 had the most effects to decompose HA (Humic acid) compound in physicochemical pre-treatment and treatment stages.

Monetizing and selection of sustainable tannery sludge-to-energy technology using a simulation-based novel integrated MCDM model along with life cycle Techno-Economic-ESG analysis

Tannery sludge (TS) is a harmful, hazardous byproduct of the leather processing industry. This industrial solid waste generally undergoes uncontrolled landfilling and pollutes the surrounding environment, including water, air, and soil. Thus, to protect the environment and promote sustainable development goals (SDGs), an innovative TS valorization process design is urgently necessary. Nonetheless, the previous literature mainly focused on the physicochemical characteristics of TS and entirely ignored developing innovative processes for energy recovery. Further, there is a lack of study on developing life cycle techno-economic, environmental, social, and governance (T-E-ESG) frameworks for the TS-to-energy recovery scheme selection in an uncertain environment. To address these gaps, this study, for the first time, develops a simulation-based data-driven life cycle T-E-ESG framework for assessing TS-to-energy recovery schemes. A comprehensive fuzzy Delphi and hybrid weighting method (fuzzy-based best-worst method and level-based weight assessment) integrated with the fuzzy Bonferroni combined compromise solution (CoCoSo) model are proposed for evaluating TS-to-energy recovery schemes based on the T-E-ESG framework. The extended literature review identified thirty T-E-ESG factors, further verified using the fuzzy Delphi technique. The findings of the hybrid weighting method confirmed that the two most important factors are ‘Revenue per day with subsidy’ and ‘Energy efficiency’. The fuzzy Bonferroni CoCoSo analysis indicated ‘TS to power generation with carbon capture’ as the optimal solution for TS valorization as it received the highest relative significance score value of 2.2655, which ensured its’ suitability for real-time implication. The study findings may be used as a benchmark for the policymakers to establish optimal TS-to-energy recovery plant in developing countries.

Facile and sustainable upcycling of fly ash into multifunctional durable superhydrophobic coatings

Fly ash (FA), a hazardous byproduct of coal combustion in power plants, poses significant environmental and health risks due to improper disposal and utilization. This study introduces a facile, sustainable, and cost-effective method for converting FA into a robust superhydrophobic material for various substrates. -FA particles are modified with polydopamine (PD) in water and covalently grafted with octadecylamine (ODA) via the Michael Addition-Schiff Base reactions, resulting in robust superhydrophobic FA (SH-FA) with a water contact angle (WCA) of 163° (±3.1). When applied as a coating to jute, cotton, polyester fibers, PU sponge, and wood, they became superhydrophobic, with WCAs ranging from 154.7 to 161.2° except for the wood substrate, which achieved a WCA of 132° (±3°). The coated polyester fabric exhibited remarkable durability, retaining consistent WCA values after 70 abrasion cycles, 75 adhesive tape peelings, and 20 detergent washing cycles. It also showcased excellent self-cleaning properties, effectively repelling dust and various liquids. Additionally, the coated PU sponge demonstrated exceptional performance in separating oil from different oil/water mixtures, achieving rapid separation of organic solvents within seconds and maintaining a separation efficiency of over 98% even after 12 reuse cycles. These results indicate the potential for transforming FA through effective management.

Role of nanocomposites and nano adsorbents for heavy metals removal and dyes. An overview

Water scarcity and wastewater treatment are major concerns due to increased urbanization, industrialization, and anthropogenic practices. Various toxic heavy metals, dyes, pollutants, and chemicals are a matter of concern as they have severe environmental and ecological damage and health effects. Various advancements are being introduced in the field of adsorption using nano adsorbents and composites to deal with wastewater treatment problems. Nanocomposites are intelligent to eliminate bacteria, viruses, and inorganic and organic pollutants from wastewater due to precise binding action (chelation, absorption, ion exchange). Nanocomposite materials, such as metal nanocomposite, metal oxide nanocomposite, carbon nanocomposite, polymer nanocomposite, and membrane nanocomposite, are active in water purification. Nanoparticles (N.P.s) are important for remediation because of their large surface area, size, reactivity, and active sites. For high adsorption of pollutants, N.P.s were treated by increasing the electron density and surface area and adding functional groups. They are more capable of eliminating hazardous organic-inorganic pollutants, pathogens, and heavy metals from wastewater. This nanotechnology treatment technique has no hazardous by-products; these techniques have various regenerative efficiencies. Among various treatment methods, the adsorption process is considered one of the most highly effective treatments of heavy metals, and the functionalization of adsorbents can fully enhance the adsorption process. Therefore, four adsorbent sources are highlighted: polymeric, natural mineral, industrial by-product, and carbon nanomaterial adsorbent. The major purpose of this review is to gather up-to-date information on research and development on various adsorbents in the treatment of heavy metal and dyes from water by emphasizing the adsorption capability, the effect of pH, isotherm and kinetic model, removal efficiency, and the contact of time of every adsorbent.

Nano-Bioremediation of Arsenic and Its Effect on the Biological Activity and Growth of Maize Plants Grown in Highly Arsenic-Contaminated Soil.

Arsenic (As)-contaminated soil reduces soil quality and leads to soil degradation, and traditional remediation strategies are expensive or typically produce hazardous by-products that have negative impacts on ecosystems. Therefore, this investigation attempts to assess the impact of As-tolerant bacterial isolates via a bacterial Rhizobim nepotum strain (B1), a bacterial Glutamicibacter halophytocola strain (B2), and MgO-NPs (N) and their combinations on the arsenic content, biological activity, and growth characteristics of maize plants cultivated in highly As-contaminated soil (300 mg As Kg-1). The results indicated that the spectroscopic characterization of MgO-NPs contained functional groups (e.g., Mg-O, OH, and Si-O-Si) and possessed a large surface area. Under As stress, its addition boosted the growth of plants, biomass, and chlorophyll levels while decreasing As uptake. Co-inoculation of R. nepotum and G. halophytocola had the highest significant values for chlorophyll content, soil organic matter (SOM), microbial biomass (MBC), dehydrogenase activity (DHA), and total number of bacteria compared to other treatments, which played an essential role in increasing maize growth. The addition of R. nepotum and G. halophytocola alone or in combination with MgO-NPs significantly decreased As uptake and increased the biological activity and growth characteristics of maize plants cultivated in highly arsenic-contaminated soil. Considering the results of this investigation, the combination of G. halophytocola with MgO-NPs can be used as a nanobioremediation strategy for remediating severely arsenic-contaminated soil and also improving the biological activity and growth parameters of maize plants.

The Catalytic Potential of Modified Clays: A Review

The need for innovative catalysts and catalytic support materials is continually growing due to demanding requirements, stricter environmental demands, and the ongoing development of new chemical processes. Since about 80% of all industrial processes involve catalysts, there is a continuing need to develop new catalyst materials and supports with suitable qualities to meet ongoing industrial demands. Not only must new catalysts have tailored properties, but they must also be suitable for large-scale production through environmentally friendly and cost-effective processes. Clay minerals, with their rich history in medicine and ceramics, are now emerging as potential catalysts. Their transformative potential is exemplified in applications such as hydrogenating the greenhouse gas CO2 into carbohydrate fuel, a crucial step in meeting the rising electrical demand. Moreover, advanced materials derived from clay minerals are proving their mettle in diverse photocatalytic reactions, from organic dye removal to pharmaceutical pollutant elimination and photocatalytic energy conversion through water splitting. Clay minerals in their natural state show a low catalytic activity, so to increase their reactivity, they must be activated. Depending on the requirements of a particular application, selecting an appropriate activation method for modifying a natural clay mineral is a critical consideration. Traditional clay mineral processing methods such as acid or alkaline treatment are used. Still, these have drawbacks such as high costs, long processing times, and the formation of hazardous by-products. Other activation processes, such as ultrasonication and mechanical activation routes, have been proposed to reduce the production of hazardous by-products. The main advantage of ultrasonication and microwave-assisted procedures is that they save time, whereas mechanochemical processing is simple and efficient. This short review focuses on modifying clay minerals using various new methods to create sophisticated and innovative new materials. Recent advances in catalytic reactions are specifically covered, including organic biogeochemical processes, photocatalytic processes, carbon nanotube synthesis, and energy conversion processes such as CO2 hydrogenation and dry reforming of methane.

Exploring the Potential of Endophytic Microorganisms and Nanoparticles for Enhanced Water Remediation.

Endophytic microorganisms contribute significantly to water bioremediation by enhancing pollutant degradation and supporting aquatic plant health and resilience by releasing bioactive compounds and enzymes. These microorganisms inhabit plant tissues without causing disease or any noticeable symptoms. Endophytes effectively aid in eliminating contaminants from water systems. Nanoparticles serve as potent enhancers in bioremediation processes, augmenting the efficiency of pollutant degradation by increasing surface area and bioavailability, thereby improving the efficacy and rate of remediation. Their controlled nutrient release and ability to stabilize endophytic colonization further contribute to the enhanced and sustainable elimination of contaminated environments. The synergistic effect of endophytes and nanoparticles in water remediation has been widely explored in recent studies, revealing compelling outcomes. Water pollution poses significant threats to human health, ecosystems, and economies; hence, the sixth global goal of the Sustainable Development Agenda 2030 of the United Nations aims to ensure the availability and sustainable management of water resources, recognizing their crucial importance for current and future generations. Conventional methods for addressing water pollution exhibit several limitations, including high costs, energy-intensive processes, the production of hazardous by-products, and insufficient effectiveness in mitigating emerging pollutants such as pharmaceuticals and microplastics. Noticeably, there is an inability to effectively remove various types of pollutants, thus resulting in incomplete purification cycles. Nanoparticle-enhanced water bioremediation offers an innovative, eco-friendly alternative for degrading contaminants. A growing body of research has shown that integrating endophytic microorganisms with nanoparticles for water bioremediation is a potent and viable alternative. This review examines the potential of using endophytic microorganisms and nanoparticles to enhance water remediation, exploring their combined effects and applications in water purification. The paper also provides an overview of synthetic methods for producing endophyte-nanoparticle composites to optimize their remediation capabilities in aqueous environments. The final section of the review highlights the constraints related to integrating endophytes with nanoparticles.

Wastewater disinfection with photodynamic treatment and evaluation of its ecotoxicological effects

Research has demonstrated the presence of viruses in wastewater (WW), which can remain viable for a long period, posing potential health risks. Conventional WW treatment methods involving UV light, chlorine and ozone efficiently reduce microbial concentrations, however, they produce hazardous byproducts and microbial resistance that are detrimental to human health and the ecosystem. Hence, there is a need for novel disinfection techniques. Antimicrobial Photodynamic Inactivation (PDI) emerges as a promising strategy, utilizing photosensitizers (PS), light, and dioxygen to inactivate viruses. This study aims to assess the efficacy of PDI by testing methylene blue (MB) and the cationic porphyrin TMPyP as PSs, along a low energy consuming white light source (LED) at an irradiance of 50 mW/cm2, for the inactivation of bacteriophage Phi6. Phi6 serves as an enveloped RNA-viruses surrogate model in WW. PDI experiments were conducted in a buffer solution (PBS) and real WW matrices (filtered and non-filtered). Considering the environmental release of the treated effluents, this research also evaluated the ecotoxicity of the resulting solution (post-PDI treatment effluent) on the model organism Daphnia magna, following the Organisation for Economic Cooperation and Development (OECD) immobilization technical 202 guideline. Daphnids were exposed to WW containing the tested PS at different concentrations and dilutions (accounting for the dilution factor during WW release into receiving waters) over 48 h. The results indicate that PDI with MB efficiently inactivated the model virus in the different aqueous matrices, achieving reductions superior to 8 log10 PFU/mL, after treatments of 5 min in PBS and of ca. 90 min in WW. Daphnids survival increased when subjected to the PDI-treated WW with MB, considering the dilution factor. Overall, the effectiveness of PDI in eliminating viruses in WW, the fading of the toxic effects on daphnids after MB’ irradiation and the rapid dilution effect upon WW release in the environment highlight the possibility of using MB in WW PDI-disinfection.

Ultrasensitive Indium Phosphide Nanomembrane Wearable Gas Sensors

Air quality is deteriorating due to continuing urbanization and industrialization. In particular, nitrogen dioxide (NO2) is a biologically and environmentally hazardous byproduct from fuel combustion that is ubiquitous in urban life. To address this issue, we report a high‐performance flexible indium phosphide nanomembrane NO2 sensor for real‐time air quality monitoring. An ultralow limit of detection of ~200 ppt and a fast response have been achieved with this device by optimizing the film thickness and doping concentration during indium phosphide epitaxy. By varying the film thickness, a dynamic range of values for NO2 detection from parts per trillion (ppt) to parts per million (ppm) level have also been demonstrated under low bias voltage and at room temperature without additional light activation. Flexibility measurements show an adequately stable response after repeated bending. On‐site testing of the sensor in a residential kitchen shows that NO2 concentration from the gas stove emission could exceed the NO2 Time Weighted Average limit, i.e., 200 ppb, highlighting the significance of real‐time monitoring. Critically, the indium phosphide nanomembrane sensor element cost is estimated at &lt;0.1 US$ due to the miniatured size, nanoscale thickness, and ease of fabrication. With these superior performance characteristics, low cost, and real‐world applicability, our indium phosphide nanomembrane sensors offer a promising solution for a variety of air quality monitoring applications.