Search Results (231)

This review examines the research progress on non-noble-metal-based catalysts for formaldehyde (HCHO) oxidation at room temperature. It begins with an introduction to the hazards of HCHO as an indoor pollutant and the urgency of its removal, comparing several HCHO removal technologies and highlighting the advantages of room-temperature catalytic oxidation. It delves into the classification, preparation methods, and regulation strategies for non-precious metal catalysts, with a focus on manganese-based, cobalt-based, and other transition metal-based catalysts. The effects of catalyst preparation methods, morphological structure, and specific surface area on catalytic performance are discussed, and the catalytic oxidation mechanisms of HCHO, including the Eley–Rideal, Langmuir–Hinshelwood, and Mars–van Krevelen mechanisms, are analyzed. Finally, the challenges faced by non-precious metal catalysts are summarized, such as issues related to the powder form of catalysts in practical applications, lower catalytic activity at room temperature, and insufficient research in the presence of multiple VOC molecules. Suggestions for future research directions are also provided. Full article

Micropollutants (MPs), which include both natural and manmade substances, are becoming more prevalent in aquatic habitats as a result of the insufficient removal of these compounds in wastewater treatment plants (WWTPs). Advanced remediation techniques are required due to their persistence and potential ecotoxicological hazards. Although adsorption and photo(electro)catalysis exhibit potential in laboratory-scale investigations, the effects of their use in actual WWTP systems are still poorly understood. However, before large-scale application can be implemented, a number of issues need to be resolved, including material limitations, reactor design and optimization, and actual wastewater complexities. This study critically evaluates the application of adsorption and photo(electro)catalysis to actual wastewater, as well as recent advancements in adsorption and photo(electro)catalytic systems for the removal of micropollutants. We also explore the particular difficulties and strategies involved in the large-scale use of adsorption and photo(electro)catalysis in the treatment of wastewater. Emerging trends such as nanocomposites, metal–organic frameworks (MOFs), heterojunctions, and single-atom catalysts (SACs) are highlighted by the bibliometric analysis. We also evaluate MPs’ ecological effects in aquatic environments and the incorporation of artificial intelligence (AI) for process optimization. A strategy for transferring nanotechnologies from laboratory-scale research to wastewater treatment implementation is presented in this paper. In this strategy, implementation is proposed based on actual wastewater conditions, focusing on the development of adsorbents and catalysts, reactor design and optimization, synergy between adsorption and catalysis, life cycle analysis, and cost–benefit studies. Full article

Excess phosphorus (P) and nitrogen (N) in wastewater contribute to eutrophication, driving the need for low–cost and sustainable recovery technologies. This study presents a novel adsorbent synthesized from spent coffee grounds biochar (CB) chemically modified with Mn²⁺/Zn²⁺/Fe³⁺ (oxy)hydroxide nanoparticles (CB–M) for simultaneous removal of phosphate and ammonium. Batch adsorption experiments using both synthetic solution and municipal wastewater were conducted to evaluate the material’s adsorption performance and practical applicability. Kinetic, isotherm, thermodynamic, and sequential extraction analyses revealed that CB–M achieved maximum phosphate adsorption capacities ranging from 42.6 to 72.0 mg PO₄³⁻·g⁻¹ across temperatures of 20–33 °C, reducing effluent phosphate concentrations to below 0.01 mg·L⁻¹. Ammonium removal was moderate, with capacities ranging between 2.8 and 2.95 mg NH₄⁺·g⁻¹. Thermodynamic analysis indicated that phosphate adsorption was spontaneous and endothermic, dominated by inner–sphere complexation, while ammonium uptake occurred primarily through weaker, reversible ion exchange mechanisms. Sequential extraction showed over 70% of adsorbed phosphate was associated with Fe-Mn-Zn phases, indicating the potential for use as a slow–release fertilizer. The CB–M retained structural integrity and exhibited partial desorption, supporting its reusability for nutrient recovery. Compared to other biochars, CB–M demonstrated superior phosphate selectivity at a neutral–pH, avoided the use of hazardous metals, and transformed coffee waste into a multifunctional material for wastewater treatment and soil amendment. These findings underscore the potential of CB–M as a circular economy solution for nutrient recovery without introducing secondary contamination. Full article

Natural zeolites are highly effective adsorbents that can remove various metal cations which would otherwise contaminate the environment. However, different metal cations (Cu, Zn, and Ag) within their lattice or quaternary long-chain surfactant cations on their surface modify their affinity towards hazardous anions and promote antibacterial activity in natural zeolites. Specifically, natural zeolites in their non-modified form lack intrinsic antibacterial characteristics. NZ is the most widespread natural zeolite. This review presents the antibacterial efficiency of NZ containing transition metals, nano oxides, and organics. This effect is nonspecific and primarily driven by the nutritional makeup of the medium rather than the species of pathogenic bacteria under study. Studies on using NZ-based disinfectants to clean up contaminated water and soil and using modified and purified NZ to protect health are also considered. By eliminating toxic ions and, when modified by these toxic cations, removing pathogens from the environment, natural NZ can serve a dual function, providing it with the distinctive characteristics of a sustainable material. Full article

Extreme precipitation events are one of the common hazards in eastern Texas, generating a large amount of storm water. Water running off urban areas may carry non-point source (NPS) pollution to natural resources such as rivers and lakes. Urbanization exacerbates this issue by increasing impervious surfaces that prevent natural infiltration. This study evaluated the efficacy of rain gardens, a nature-based best management practice (BMP), in mitigating NPS pollution from urban stormwater runoff. Stormwater samples were collected at inflow and outflow points of three rain gardens and analyzed for various water quality parameters, including pH, electrical conductivity, fluoride, chloride, nitrate, nitrite, phosphate, sulfate, salts, carbonates, bicarbonates, sodium, potassium, aluminum, boron, calcium, mercury, arsenic, copper iron lead magnesium, manganese and zinc. Removal efficiencies for nitrate, phosphate, and zinc exceeded 70%, while heavy metals such as lead achieved reductions up to 80%. However, certain parameters, such as calcium, magnesium and conductivity, showed increased outflow concentrations, attributed to substrate leaching. These increases resulted in a higher outflow pH. Overall, the pollutants were removed with an efficiency exceeding 50%. These findings demonstrate that rain gardens are an effective and sustainable solution for managing urban stormwater runoff and mitigating NPS pollution in eastern Texas, particularly in regions vulnerable to extreme precipitation events. Full article

Heavy metal and pesticide contaminations represent significant environmental and health hazards to humans and animals. Toxic heavy metals such as lead (Pb), cadmium (Cd), mercury (Hg), and copper (Cu) persist in the environment, bioaccumulating in beverages and food products from both natural and anthropogenic sources. Traditional remediation techniques, such as chemical precipitation and ion exchange, are effective but often costly and challenging to apply at a large scale. In recent years, grape pomace—a winemaking by-product rich in bioactive compounds—has emerged as a promising, low-cost biosorbent for the removal of such pollutants. Its high adsorption capacity, environmental friendliness, and availability make it a strong candidate for water and food decontamination processes. This study evaluates grape pomace and its biochar as sustainable biosorbents for heavy metal removal from water and soil, examining their adsorption efficiency, adsorption mechanisms, environmental benefits, advantages, limitations, and perspectives for future industrial-scale applications. Full article

The growing diversity and prevalence of contaminants of emerging concern (CECs) in aquatic environments present significant risks to human health and ecosystems, necessitating the development of effective remediation strategies. Advanced oxidation processes (AOPs) have emerged as a promising solution due to their ability to produce highly reactive species that efficiently degrade persistent contaminants. Among the various oxidizing agents, peracetic acid (PAA) has attracted significant attention in the field of water treatment for its powerful oxidative properties, environmentally safe decomposition, and ease of use. This article is designed to offer a comprehensive overview of the latest trends in PAA-based AOPs. The discussion begins with an overview of the intrinsic performance of PAA, emphasizing its oxidation potential and degradation mechanisms. Subsequently, the effectiveness of PAA-based AOPs in remediating CECs is explored, focusing on transition metal-mediated activation (Fe, Co, Mn), UV irradiation, and carbon-based catalysts, all of which enhance the generation of reactive species (RS). Next, the determination of RS in PAA-based AOPs is examined, distinguishing between free radical (organic and inorganic) and non-radical (singlet oxygen and high-valent metal) mechanisms that govern pollutant degradation. Then, key factors affecting the removal of CECs in PAA-based AOPs, including initial PAA concentration, catalyst dosage, and pH, are also addressed. Following that, the potential by-products and hazard assessments associated with PAA oxidation are discussed. Finally, current challenges and future research directions are proposed to facilitate the large-scale application of PAA-based AOPs in water remediation. Full article

A high-throughput method for the determination of a variety of chemical hazards in poultry muscle and egg samples was established via ultra-performance liquid chromatography–tandem triple quadrupole mass spectrometry (UPLC–QqQ-MS). The sample preparation procedure was developed based on this quick, easy, cheap, effective, rugged, and safe (QuEChERS) method and validated for 280 chemical hazards potentially present in poultry products. The target compounds in poultry samples were extracted with a 1% formic acid–acetonitrile solution (15:85, v/v), and the metal ions in the matrix were chelated by adding ethylenediaminetetraacetic acid disodium salt (Na₂EDTA). The supernatant was purified using Enhanced Matrix Removal (EMR) lipid sorbent. Chromatographic gradient separation was performed on an ACQUITY UPLC BEH C18 (2.1 mm × 100 mm, 1.7 μm) column with multiple reaction monitoring (MRM) under both negative- and positive-ion mode. Internal standard calibration or matrix-matched calibration was used for the quantitation. The results showed that good linearity was achieved for each target compound with correlation coefficients (R²) ≥ 0.99. The limits of detection (LODs) ranged from 0.05 to 10 µg/kg, and the acceptable limits of quantification (LOQs) were determined to be 0.1–20 µg/kg for all 280 compounds. Approximately 90% of the target compounds exhibited mean recoveries ranging from 60% to 120%, with relative standard deviations (RSDs) within 16.2%. This method can be used for the high-throughput rapid detection of prohibited drug residues in poultry eggs due to its easy operation and high accuracy. It was applied in real sample detection, and 43 chemicals including metronidazole were found in 211 poultry samples, with a concentration range of 0.11–638 μg/kg. Full article

To address the limitations of low CuO loading and poor dispersion in conventional supported adsorbents, in this study, MOF (metal–organic framework)-derived CuO with Ce doping (Cu_xCe_yO) was synthesized and used for the adsorption–oxidation of PH₃ under low-temperature and low-oxygen conditions. The results demonstrated that Ce doping increased the PH₃ capacity of the adsorbent from 75.54 mg·g⁻¹ (MOF-derived CuO) to 226.87 mg·g⁻¹ (Cu₁Ce_0.2O). The characterization results indicated that Ce doping significantly altered the physicochemical properties of CuO. Specifically, Cu₁Ce_0.2O exhibited optimal CuO dispersion, the highest adsorbed oxygen concentration, superior redox performance, an increased number of basic sites, and a larger specific surface area and pore volume, all contributing to its improved performance. Analysis of the exhausted adsorbent revealed the formation of Cu₃P and phosphoric acid. And the deactivation of the adsorbent can be attributed to the consumption of CuO and the blockage of pore structure. Surprisingly, the exhausted adsorbent demonstrated considerable photocatalytic performance due to the formation of Cu₃P, enabling the resource utilization of the waste adsorbent, making it a promising material for the adsorption–oxidation of PH₃. This waste-to-resource conversion reduces hazardous solid waste while creating value-added photocatalysts, establishing a sustainable lifecycle from pollutant removal to functional material regeneration. Full article

The occurrence of heavy metals in aquatic ecosystems is a serious environmental hazard, and their effective removal is imperative. In this regard, the feasibility of living microalga Chlorella vulgaris (C. vulgaris) to remove heavy metals (Ni, Pb, Zn, Cd, and Cu) is investigated by using 1, 5, and 10 ppm concentrations of single- and multiple-metal-treated (MT) cultures. Experiments were performed in controlled laboratory conditions, and metal removal analysis was performed through atomic absorption spectroscopy (AAS). The cultures were also examined by means of optical microscopy, UV-Vis spectrophotometry, and Fourier transform infrared (FTIR) spectroscopy to follow the cultures’ pigment content, cell population, and functional group changes during cultivation. The removal efficiency results of both single and multiple MT cultures were evaluated using the Langmuir isotherm model. The results indicate that C. vulgaris presents potential for heavy metal bioremediation, even towards multi-MT conditions, despite the influence of a competitive uptake in multi-MT cultures. In mono-MT cultures, the removal efficiency of C. vulgaris presents values of 65–99% on Day 3 and 72–99% on Day 7 of cultivation, while the results for the multi-MT cultures are 49–99% and 62–99% for Days 3 and 7 of cultivation, respectively. The research illustrates the potential for C. vulgaris as a promising biosorbent for heavy metal remediation along with its post-treatment use in applications supporting the green circular economy. Full article

Addressing hazards from dangerous pollutants requires specialized techniques and risk-control strategies, including detection, neutralization and disposal of contaminants. Smart polymers, designed for specific contaminants, provide powerful solutions for hazardous compound challenges. Their remarkable performance capabilities and potential applications present exciting opportunities for further exploration and development in this field. This editorial aims to provide a comprehensive overview of smart materials with unique features and emerging polymeric technologies that are being developed for isolation, screening, removal, and decontamination of hazardous compounds (e.g., heavy metals, pharmaceutically active contaminants, hormones, endocrine-disrupting chemicals, pathogens, and energetic materials). It highlights recent advancements in synthesis methods, characterization, and the applications of molecularly imprinted polymers (MIPs), along with alternative smart polymeric platforms including hydrogels, ion-imprinted composites, screen-printed electrodes, nanoparticles, and nanofibers. MIPs offer highly selective recognition properties, reusability, long-term stability, and low production costs. Various MIP types, including particles and films, are used in applications like sensing/diagnostic devices for hazardous chemicals, biochemicals, pharmaceuticals, and environmental safety. Full article

Hexavalent chromium (Cr(VI)), a highly toxic and carcinogenic contaminant, presents a significant hazard to aquatic ecosystems and human health. Developing environmentally friendly, cost-effective, biodegradable, and easily recyclable adsorbents is critical for efficient Cr(VI) removal. Here, we present an innovative solution using a Mg/Al layered double hydroxide (LDH)-modified sphagnum cellulose gel (MgAl/LDH@SMCG), prepared by pre-treating sphagnum cellulose, crosslinking with polyvinyl alcohol, and doping with LDH. The resulting porous composite gel features abundant -COOH and -OH chelating groups, significantly enhancing its adsorption capacity and structural stability. The material’s structure and surface modifications were systematically characterized using SEM, TGA, FT-IR, and XPS. Batch adsorption experiments were conducted to assess the influence of adsorbent dosage, initial Cr(VI) concentration, pH, contact time, and temperature on performance. Adsorption kinetics, isotherms, and thermodynamics analyses revealed a primary mechanism of monolayer chemical adsorption, with experimental data closely fitting the Freundlich isotherm and pseudo-second-order kinetic models. The modified gel exhibits increased surface roughness and adsorption sites, resulting in markedly improved Cr(VI) removal efficiency. This study not only provides theoretical insights into Cr(VI) adsorption but also highlights the potential of LDH-functionalized cellulose gels for heavy metal wastewater treatment, offering a sustainable pathway for addressing global water contamination challenges. Full article

During the natural cooling process of magnesium slag stockpiles in the open air, the phase transformation of gamma-dicalcium silicate (γ-C₂S) induces a powdering phenomenon, resulting in the generation of a large amount of PM10 and PM2.5 dust. Based on the dust emission model of stockpiles and the Gaussian dispersion model, combined with the Monte Carlo simulation method, this study conducted a quantitative assessment of the environmental risk of heavy metals (Pb, Cd, Hg, As, Cr(VI)) in dust to the surrounding residential areas. The results show that the enrichment degree of heavy metals in PM2.5 is significantly higher than that in PM10. At a downwind distance of 1000 m, the exceedance multiples of Cr(VI), As, and Cd reach 131.5, 23.6, and 51.8 times, respectively. The total carcinogenic risk (9.2 × 10⁻⁷) and total non-carcinogenic hazard quotient (0.15) in the residential area are below the limits, but the contribution rates of As and Cd are relatively high. Sensitivity analysis further reveals that the moisture content of the stockpile, dust removal rate, and distance are the key control parameters affecting the environmental risk. Based on the research findings, it is recommended to increase sprinkling frequency, install windbreak nets, and promote magnesium slag utilization to effectively control dust risks. Full article

Structural research teams face significant challenges when conducting studies with explosives, including the costs and inherent risks associated with field detonation tests. This study presents a replicable method for loading spherical and bare TNT-based cast explosive charges, offering reduced costs and minimal risks. Over eighty TNT and Composition B charges (comprising 60% RDX, 39% TNT, and 1% wax) were prepared using spherical molds made of thin aluminum, which are low-cost, off-the-shelf solutions. The charges were bare, meaning they lacked any casing, as the molds were designed to be easily removed after casting. The resulting charges were safer due to their smaller dimensions and the absence of hazardous metallic debris. Composition B charges demonstrated promising results, with their performance characterized through blast and thermochemical experiments. Comprehensive data are provided for Composition B charges, including TNT equivalence, pressures, velocity of detonation, DSC/TGA curves at four different heating rates, activation energy, peak decomposition temperatures, X-ray analysis, and statistics on masses and densities. A comparison between detonation and deflagration processes, captured in high-speed footage, is also presented. This explosive characterization is crucial for structural teams to precisely understand the blast loads produced, ensuring a clear and accurate knowledge of the forces acting on structures. Full article

The toxicity of hazardous dyes like rhodamine B and heavy metal ions like lead warrants the need for wastewater remediation. We describe here the functionalization of cobalt-doped iron oxide (Co_0.1Fe_2.9O₄) magnetic nanoparticles (MNPs) with citrate moieties for the effective sequestration of rhodamine B dye and lead ions from contaminated water. Citrate-functionalized MNPs are prepared using a co-precipitation technique. For the uncoated MNPs, the hydrodynamic diameter and zeta potential are found to be 21 nm and ~45 ± 3.1 mV, respectively. The hydrodynamic diameters are found to increase to ~51, ~59, and ~68 nm for the MNPs functionalized with ~20, ~40, and ~60 mg/mL of citrate, respectively, whereas the corresponding zeta potentials are found to be ~−27.95 ± 3.5 mV, ~−32.5 ± 3.6 mV, and ~−33.9 ± 3.5 mV, respectively. The chemisorption of the citrate moieties over the MNPs cause the zeta potential to be negative, a phenomenon which is further verified from the citrate-specific absorption bands in the Fourier transform infrared (FTIR) spectra of the surface-functionalized MNPs. UV-visible spectrophotometry is employed to probe the MNP-aided elimination of rhodamine B dye and lead ions from aqueous media, where the absorption bands at ~554 nm and ~375 nm (for lead (II)-5-dimercapto-1,3,4-thiadiazole chelate) are utilized for quantitative analyses. These citrate-functionalized nanoparticles are found to successfully remove the toxic rhodamine B dye and lead ions from water, with removal efficiencies of ~93.7 ± 2.6% and ~90 ± 2.4%, respectively. The unbound -COO⁻ functional groups of the citrate-functionalized MNPs electrostatically interact with the cationic rhodamine B dye or lead (II) ions, thereby leading to the adsorption onto the surface-functionalized MNPs and the subsequent magnetic-field-assisted removal. The experimental findings show the efficacy of the citrate-functionalized cobalt-doped iron oxide MNPs for the sequestration of dye pollutants and lead ions from contaminated water. Full article