Search Results (30)

In response to the European Union’s revised Urban Wastewater Treatment Directive, which mandates enhanced monitoring and advanced treatment of micropollutants, this study was conducted. It took place within the Coastal Landscape Park (CLP), a Natura 2000 protected area in northern Poland. The focus was on the municipal wastewater treatment plant in Jastrzębia Góra, located in a region exposed to seasonal tourist pressure and discharging effluent into the Czarna Wda River. A total of 90 wastewater samples were collected during five monitoring campaigns (July, September 2021; February, May, July 2022) and analysed for 13 pharmaceuticals and personal care products (PPCPs) using ultra-high-performance liquid chromatography tandem mass spectrometry with electrospray ionisation (UHPLC-ESI-MS/MS). The monitoring included both untreated (UTWW) and treated wastewater (TWW) to assess the PPCP removal efficiency and persistence. The highest concentrations in the treated wastewater were observed for metoprolol (up to 472.9 ng/L), diclofenac (up to 3030 ng/L), trimethoprim (up to 603.6 ng/L) and carbamazepine (up to 2221 ng/L). A risk quotient (RQ) analysis identified diclofenac and LI-CBZ as priority substances for monitoring. Multivariate analyses (PCA, HCA) revealed co-occurrence patterns and seasonal trends. The results underline the need for advanced treatment solutions and targeted monitoring, especially in sensitive coastal catchments with variable micropollutant presence. Full article

This study investigated the enhancement in lipid accumulation in Chlorella sp. using non-thermal atmospheric pressure plasma as a pretreatment strategy for the production of value-added products. The plasma treatment was optimized by varying discharge times (0–16 min) using argon gas at a flow rate of 4 L/min. Lipid productivity was assessed through gravimetric analysis and profiling of fatty acid methyl ester using gas chromatography−mass spectrometry (GC-MS). The growth rate and pH of the treated cells were monitored. The findings demonstrated that the 4-min plasma exposure maximized the efficiency of lipid recovery, achieving a 35% of the dry cell weight and a 34.6% increase over untreated control. However, longer plasma treatment times resulted in a comparative decrease in lipid yield, as the decline is possibly due to oxidative degradation. The findings highlight the role of plasma treatment, which significantly boosts lipid yield and gives complementary optimization of downstream processes to improve biodiesel production. The accumulation of lipids in terms of size and volume in the algal cells was assessed by confocal laser scanning microscopy. The GC–MS results of the control revealed that lipids comprised primarily mixed esters such as 2H Pyran 2 carboxylic acid ethyl esters, accounting for 50.97% and 20.52% of the total peak area. In contrast, the 4-min treated sample shifted to saturated triacylglycerols (dodecanoic acid, 2,3 propanetriyl ester), comprising 85% of the total lipid content, which efficiently produced biodiesel. Thus, the non-thermal plasma-based enhancement of lipids in the algal cells has been achieved. Full article

Aiming at the defects of the low mass transfer efficiency and large floor space of the traditional ozone process, a cross-tube ozone catalytic oxidation pilot plant was designed and developed. By implementing lateral aeration and a modular series configuration, the gas–liquid mass transfer pathways were optimized, achieving a hydraulic retention time of 25 min and maintaining an ozone dosage of 43 mg/L, which significantly improved the ozone utilization efficiency. During the pilot operation in an industrial park in Suzhou, Anhui Province, the average COD removal efficiency of the device for the actual biochemical tail water (COD 82.5~29.7 mg/L) reached 35.47%, and the effluent concentration was stably lower than 50 mg/L, which meets the stricter discharge standard. The intermediate products in the system were also analyzed by liquid chromatography–mass spectrometry (LC-MS), and the key pollutants were selected for degradation path analysis. Compared to the original tower process in the park, the ozone dosage was reduced by 46%, the reaction residence time was reduced by 60%, and the cost of water treatment was reduced to 0.067 USD, which is both economical and applicable to engineering. This process provides an efficient and low-cost solution for the deep treatment of wastewater in industrial parks, and has a broad engineering application prospect. Full article

This study investigates the degradation mechanisms of fiber-reinforced polymer (FRP) matrices in composite insulators under partial discharge (PD) conditions. The degradation products may further cause deterioration of the electrical and chemical resistance (ECR) glass fibers. Using pyrolysis–gas chromatography-mass spectrometry (PY-GC-MS) and high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS-MS), the thermal degradation gas and liquid products of the degraded FRP matrix were analyzed, revealing the presence of organic acids. These acids form when the epoxy resin’s cross-linked bonds break at high temperatures, generating anhydrides that hydrolyze into carboxylic acids in the presence of moisture. The hydrolyzation process is accelerated by hydroxyl radicals produced during PD. The resulting carboxylic acids deteriorate the glass fibers within the FRP matrix by degrading surface coupling agents and reacting with the alkali metal–silica network, leading to the substitution and precipitation of metal ions. Organic acids, particularly carboxylic acids, were found to have a more severe deteriorating effect on glass fibers compared to inorganic acids, with high temperatures exacerbating this process. These findings provide critical insights into the deterioration mechanisms of FRP under operational conditions, offering valuable guidance for optimizing manufacturing processes and enhancing the longevity of composite insulators. Full article

High-purity aluminum is widely used in metallurgy, microelectronics and chemical synthesis. In this work, the method of carbothermic reduction of aluminum powder in a microwave plasma discharge with the formation of valuable organic products such as synthesis gas, acetylene and benzene was used. Al powder was studied by inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy (SEM) and powder X-ray diffraction (XRD). The yield of by-products was studied by gas chromatography equipped with a mass spectrometer, as well as optical emission spectroscopy of plasma discharge. High-purity aluminum powder reduced with the plasma was used to synthesize oxygen-free trimethylaluminum (TMA). For the first time, TMA was synthesized in one vacuum cycle without the system depressurizing to improve the purity of the final product. Trimethylaluminum was analyzed by gas chromatography, which confirmed that the main substance is ≥99.99% pure. Gas chromatography with a mass spectrometer was used to determine by-products and residual reaction products. Additionally, ICP-MS was used to confirm trace metal concentrations, achieving the 7N standard for ultra-high-purity materials. Full article

Malodorous gases—particularly hydrogen sulfide (H₂S), ammonia (NH₃), and volatile sulfur compounds (VSCs)—significantly degrade water quality, threaten public health, and disrupt ecosystems. Their production stems from microbial activity, nutrient overload, and industrial discharges, often magnified by low dissolved oxygen. This review integrates current insights into the microbial sulfur and nitrogen cycles to elucidate how these gases form, and surveys advances in detection technologies such as gas chromatography and laser-based sensors. We also assess diverse mitigation methods—including biotechnological approaches (e.g., biofilters, biopercolators), physicochemical treatments, and chemical conversion (Claus Process)—within relevant regulatory contexts in Colombia and worldwide. A case study of the Bogotá River exemplifies how unmanaged effluents and eutrophication perpetuate odor issues, underscoring the need for integrated strategies that reduce pollution at its source, restore ecological balance, and employ targeted interventions. Overall, this review highlights innovative, policy-driven solutions and collaborative efforts as pivotal for safeguarding aquatic environments and surrounding communities from the impacts of odorous emissions. Full article

High-performance cross-linked polyethylene (XLPE) is currently employed in ultra-high-voltage direct current (UHVDC) cables, with the electrical tree being an important cause of DC cable breakdown. The comparison of XLPE samples under different manufacturing processes can provide a reference for the progress of cable production processes. This paper compares laboratory-prepared XLPE samples (DC-XLPE) with XLPE samples extracted from actual cables (Cable-XLPE) through electrical tree experiments, X-ray diffraction (XRD), and gel permeation chromatography (GPC). The experimental findings indicate that the breakdown time of DC-XLPE increased by nearly 50% compared to Cable-XLPE, with slower electrical tree growth and lower average discharge magnitude observed. Overall, DC-XLPE exhibited superior resistance to DC electrical tree and partial discharge. XRD and GPC analyses revealed minimal differences in crystallinity and grain size between the two types, with the primary distinction being DC-XLPE’s notably higher molecular weight and more concentrated molecular weight distribution. The differences in physicochemical properties may be attributed to more precise and uniform temperature control during the crosslinking process in laboratory settings, as well as a higher removal rate of crosslinking byproducts, ultimately leading to enhanced resistance to electrical tree and partial discharge in DC-XLPE. Full article

This study investigated the effect of dielectric barrier discharge (DBD) on sea cucumber polysaccharide (SP-2) and evaluated its anti-inflammatory properties. The SP-2 was depolymerized by applying an input voltage of 60~90 V for 3~9 min. The features of the products were examined using high-performance gel permeation chromatography, HPLC-PAD-MS, and the Fourier transform infrared (FTIR) spectrum. The anti-inflammatory properties of the product were investigated by measuring nitric oxide (NO) release, ROS accumulation, and cell migration using RAW264.7 cells (LPS-induced or not-induced). The results showed SP-2 depolymerized into homogeneous and controllable-size oligosaccharide products. The depolymerized ratio can reach 80%. The results of the measurement of reducing sugars indicate that SP-2 was cleaved from within the sugar chain. The SP-2 was deduced to have a monosaccharide sequence of GlcN-Man-Man-Man-Man-Man based on the digested fragment information. The depolymerization product restrained the release of NO and the accumulation of ROS. By testing the RAW264.7 cell scratch assay, it was found that it enhances the migration of immune cells. DBD degradation of SP-2 leads to homogeneous and controllable-size oligosaccharide products, and this technique can be used for polysaccharide structure analysis. The depolymerized product of SP-2 has an anti-inflammatory capability in vitro. Full article

Pharmaceuticals and personal care products (PPCPs), such as statins and beta-blockers, are commonly used to treat cardiovascular disease in adults. Active versions of these pharmaceuticals and their various metabolites enter surface waters via wastewater treatment plant (WWTP) discharge, as well as from other point sources. Sub-lethal effects of statins and beta-blockers on wild fish at environmental concentrations have been understudied up to this point. The objectives of this study were to use several health condition metrics and determine if there was a relationship between fish condition and environment concentrations of statins and beta-blockers near two West Virginia WWTPs. Water samples were collected from upstream, downstream, and effluent pipe from August to November 2022, and analyzed for atorvastatin, simvastatin, metoprolol, and carvedilol via liquid chromatography with tandem mass spectrometry. Fish were sampled upstream, at the discharge, and downstream of each WWTP in November 2022. Fish health was assessed with three metrics: relative weight (Wr), hepatosomatic index (HSI), and gonadosomatic index (GSI). ANOVAs were used to assess differences among the health metrics based on sex, genus/species, and location relative to WWTPs. Additionally, changes in Wr relative to surface water concentrations of statins and beta-blockers was modeled with a Bayesian linear mixed effects model, with surface water concentrations as fixed effects with a random slope, while the section and genus parameters were treated as random intercepts. Surface concentrations for atorvastatin (0.47–4.36 ng/L), simvastatin (0.27–0.95 ng/L), metoprolol (2.80–21.01 ng/L), and carvedilol (0.43–0.90 ng/L) varied across sampling sections. HSI based on sex and species were nearly significant. GSI was significantly higher in females. Wr differed among genera, as well as the interaction between genus and sample section (p < 0.001). Fixed effects from the linear mixed effects model showed Wr was negatively related to simvastatin (−0.139 [−2.072–1.784]) and carvedilol (−0.262 [−2.164–1.682]) while atorvastatin (0.207 [−1.371–1.845]) and metoprolol (0.052 [−0.533–0.584]) were positively related to Wr. Individual genera responded differently to each pharmaceutical based on location, indicating that it is likely that other factors were also influencing the fish health metrics. Further research targeting individual tissues and controlled experiments with different exposure regimes will be required to further enlighten the long-term effects of cardiovascular PPCPs on fish health. Full article

Persistent Organic Pollutants (POPs), particularly the indicator polychlorinated biphenyls (PCBs), were first quantified in water and sediments of two wadis, Boujemaâ and Seybouse, as well as in the effluents from a fertilizer and phytosanitary production industrial plant (Fertial). Since these contaminated discharges end in Annaba Bay (Algeria) in the Mediterranean Sea, with a significant level of contamination, all the potential sources should be identified. In this work, this task is conducted by a multivariate analysis. Liquid–liquid extraction and gas chromatography/mass spectrometry (GC–MS) methods were applied to quantify seven PCB congeners, usually taken as indicators of contamination. The sum of the PCB concentrations in the sediments ranged from 1 to 6.4 μg/kg dw (dry weight) and up to 0.027 μg/L in waters. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used for the multivariate analysis, indicating that the main sources of PCB emissions in the bay are urban/domestic and agricultural/industrial. The outfalls that mostly contribute to the pollution of the gulf are the Boujemaâ wadi, followed by the Seybouse wadi, and finally by the Fertial cluster and more precisely the annex basin of the plant. Although referring to a specific site of local importance, the work aims to present a procedure and a methodological analysis that can be potentially applicable to further case studies all over the world. Full article

The physical and chemical characteristics of the microwave discharge in petroleum solvent during hydrogen production processes involving Ar, He, and CO₂ barbotage were studied. Gas chromatography, emission spectroscopy, high-speed photography, and shadow photography were used for diagnosis. The results demonstrated the dependence of hydrogen yield on the flow rates of Ar, He, and CO₂. The maximum yield values of hydrogen were 791 mL/min and 811 mL/min, while the maximum energy efficiency reached 135.6 NL/kWh and 162.2 NL/kWh in Nefras with Ar and He barbotage, respectively. The dynamics of discharge structure and the rotational and vibrational temperatures of C₂ molecules were studied. Full article

In this paper, the hybrid gas–liquid discharge plasma can efficiently degrade pesticide residues in water driven by nanosecond pulse power, which can achieve the simultaneous discharge process in the liquid and gas phases. The relevant factors are systematically investigated, including the waveforms of discharge current and pulse voltage, discharge images, and optical emission spectra during the discharge process. The Stark broadening of H_α calculates the electron density. The effects of the pulse peak voltage and discharge time on the emission intensities of OH (A²∑ → X²∏), N₂ (C³∏_u → B³∏_g), H_α, and O (3p⁵P → 3s⁵S⁰) are discussed in-depth by the optical emission spectra. The gas–liquid discharge plasma with an electron density of 7.14 × 10¹⁷ cm⁻³ was found. The emission intensities of OH (A²∑ → X²∏), N₂ (C³∏_u → B³∏_g), H_α, and O (3p⁵P → 3s⁵S⁰) present the rising trend by increasing the pulse peak voltage and discharge time. In addition, pyraclostrobin is adopted as the research object to study the removal efficiency of pollutants. The results confirm that pyraclostrobin can be completely degraded after 10 min of plasma treatment with the pulse peak voltage of 28 kV, and the degradation rate and energy yield was 0.323 min⁻¹, and 1.91 g/kWh, respectively. The intermediate products and the possible degradation mechanism of pyraclostrobin are further explored by combining the results of high-performance liquid chromatography–mass spectrometry (HPLC-MS/MS) and density functional theory (DFT), the developmental toxicity of the intermediate products was analyzed, which provided a scheme for the treatment of pesticide wastewater by gas–liquid discharge plasma technology. Full article

Dichlorodiphenyltrichloroethane (DDT) contamination in the Toce River in northern Italy was studied by collecting data from 2016 to 2021 upstream and downstream of a production factory which in the past had discharged technical DDT. Analysis of sediments and of bioaccumulation in different benthic invertebrate taxa (Gammaridae, Diptera, Ephemeroptera Baetidae and Heptageniidae) was carried out to assess the transfer of DDT from sediments to benthic invertebrates and the environmental risk of this legacy pollutant for the river ecosystem. DDT and its metabolites dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD), here called DDx, were analyzed by isotope dilution gas chromatography–mass spectrometry (GC-MS/MS). DDx values in sediments in upstream stations (1.14–2.25 ng g⁻¹ 1% Organic Carbon) were lower than downstream of the industrial site (5.60–7.60 ng g⁻¹ 1% Organic Carbon), often exceeding Sediment Quality Guidelines for total DDx. Peak levels derived from new inputs of parental DDT, as confirmed by fingerprint analysis. Bioaccumulation was higher at downstream sites (up to 5107 ng g⁻¹ lipid weight), confirming the bioavailability of residual DDT as well as active metabolism, with the formation of DDD and DDE. The Biota-Sediment Accumulation Factor evidenced the highest values (over 4.2) for Diptera and Gammaridae, highlighting that invertebrates can transfer contamination from sediments to the trophic chain. Linear regression models were developed to estimate DDx concentrations in benthic invertebrates from DDx concentrations in sediments. However, determination coefficients R² remained in the range of 0.36–0.51, highlighting the necessity of bioaccumulation analysis to fully estimate environmental risk. The results show that DDT contamination, even if residual, may still represent a risk due to its effective transfer to the trophic chain. Full article

The task of CO₂ decomposition is one of the components of the problem associated with global warming. One of the promising directions of its solution is the use of low-temperature plasma. For these purposes, different types of discharges are used. Microwave discharge in liquid hydrocarbons has not been studied before for this problem. This paper presents the results of a study of microwave discharge products in liquid Nefras C2 80/120 (petroleum solvent, a mixture of light hydrocarbons with a boiling point from 33 to 205 °C) when CO₂ is introduced into the discharge zone, as well as the results of a study of the discharge by optical emission spectroscopy and shadow photography methods. The main gas products are H₂, C₂H₂, C₂H₄, CH₄, CO₂, and CO. No oxygen was found in the products. The mechanisms of CO₂ decomposition in the discharge are considered. The formation of H₂ occurs simultaneously with the decomposition of CO₂ in the discharge, with a volumetric rate of up to 475 mL/min and energy consumption of up to 81.4 NL/kWh. Full article

The tidal freshwater Potomac River (TFPR) in the metropolitan Washington, DC region receives wastewater discharge from eight major wastewater treatment plants with the potential to impact water quality. A total of 85 pharmaceutical chemicals and personal care products (PPCPs) were analyzed in surface water and sediments using solid-phase extraction and QuEChERS, respectively, in conjunction with liquid-chromatography tandem mass spectrometry-multiple reaction monitoring quantitation (LC-MS/MS-MRM). A total of 52 PPCPs were quantified in both surface water and sediment. The most frequently quantified PPCPs in water included caffeine, fexofenadine, nicotine, sulfamethoxazole, hydrochlorothiazide, MDA, desvenlafaxine, and metoprolol ranging from 10 to 360 ng/L, and in sediment included diphenhydramine, escitalopram, desvenlafaxine, fexofenadine, sertraline and triclocarban ranging from 20 to 120 ng/g (dry weight). Comparisons of PPCP constituents in WTP discharge and adjacent surface water showed altered compositions reflecting dispersal and transformation processes acted quickly following contact of effluent with surface water. Although the PPCPs were present at their greatest concentrations in surface water near the WTP discharge zones, PPCP concentrations rapidly attenuated yielding mainstem TFPR concentrations relatively consistent along the freshwater reach of the tidal range in the estuary. The PPCP concentrations in sediment maximized in the tributary shoals, but also decreased in the mainstem TFPR similarly to surface water. Compositional analysis showed sorption to geosolids was the most important factor in the loss of PPCPs following WTP discharge in the tributary embayments. Full article