Organic Pollutants Research Articles

Correlation between environmental pollutant exposure and cardiopulmonary health by serum biomarker analysis in the Swedish elderly population

ABSTRACT Persistent organic pollutants (POPs) affect human health through the aryl hydrocarbon receptor (AhR) pathway and are implicated in mitochondrial dysfunction. Using data from the PIVUS study, we investigated the associations of serum AhR ligand (POP)-mediated luciferase activity (AhRL), mitochondrial ATP production inhibiting substances (MIS-ATP), and those affecting reactive oxygen species (MIS-ROS) with several metabolic syndrome (MetS) and cardiopulmonary function parameters. These include insulin resistance (HOMA-IR), inflammation, oxidative stress, and cardiopulmonary variables (FVC, FEV1, LV-EF, CCA distensibility). MIS-ATP showed significant correlations with HOMA-IR and pulmonary functions, indicating its direct impact of MIS-ATP on metabolic and pulmonary health. MIS-ROS correlated with oxidative stress markers and CCA distensibility, suggesting a role in systemic inflammatory responses. This study highlights the intricate relationships between environmental pollutant mixture and cardiopulmonary health in MetS as indicated by biomarkers of POP exposure in the elderly population, suggesting POP exposure may influence MetS onset and progression through mitochondrial dysfunction.

Cellulose acetate sheet supported gold nanoparticles for the catalytic reduction of toxic organic pollutants

Cellulose acetate sheet supported gold nanoparticles for the catalytic reduction of toxic organic pollutants

In Situ Synthesis of Exfoliated Ni(OH)2 Nanosheets and AgNPs-Embedded Functionalized Polyindole-Based Trinary Hybrid Microspheres: A Z-Scheme Photocatalyst for the Sunlight-Driven Degradation of Organic Pollutants with Enhanced Antibacterial Efficacy.

Advancing a facile one-pot synthetic approach for the fabrication of a hybrid heterojunction photocatalyst remains a significant challenge in research pursuits. Herein, a microsphere-like trinary hybrid nanocomposite has been synthesized (NH/PIn/MAA/Ag). It comprises exfoliated single- and a few-layered Ni(OH)2 (NH nanosheets), mercaptoacetate-functionalized polyindole (PIn/MAA), and Ag nanoparticles (AgNPs) through an in situ approach. The formation mechanism is based on the exfoliation of stacked Ni(OH)2 multilayers [i.e., Ni(OH)2 microflowers] and stabilization of NH nanosheets through host-guest formation of PIn/MAA, followed by the adsorption-reduction of Ag+ ions in a one-pot reaction at low temperature. Surface morphological analyses of hybrid nanocomposite microspheres have exhibited that highly dense Ni(OH)2 microflowers have been transformed into low-density layered forms (NH nanosheets) within the polymeric platform (PIn/MAA) with deposited AgNPs. An interfacial heterojunction has been developed between the components in the depletion region, leading to an improvement in photocatalytic efficiency through a synergistic effect over the components for charge separation and transfer through the heterojunction interface via solid-state mediator Ag-based Z-scheme charge transfer dynamics. The superior photocatalytic degradation of tetracycline (98.2%) by trinary hybrid microspheres can be attributed to the deteriorated recombination rate of electron-hole pairs with reduced charge transfer resistance of the heterojunction in the photocatalyst, as obvious from photoluminescence, electrochemical impedance spectroscopy, chronoamperometry, and time-resolved photoluminescence (TRPL) analyses. Moreover, the antibacterial properties of microspheres against Bacillus pumilus (Gram-positive) and Escherichia coli (Gram-negative) bacteria have validated their potential as promising materials for the overall purification of aquatic systems.

Nitrogen-doped bismuth ferrite nanozymes: Tailored electronic structure for organic pollutant degradation

The insufficient catalytic activity and non-recyclability of nanozymes are major obstacles for nanozyme-mediated water purification. Since electronic transfer is the basic essence of catalysis-mediated redox reactions, this research reveals that meticulous tuning of the electronic structure of magnetic bismuth ferrite (BiFeO3) through nitrogen doping, allows for excellent performance in organic pollutants degradation in water (including dyestuff and antibiotics), along with magnet separation-mediated recyclability. Mechanically speaking, nitrogen-doping rational optimize their peroxidase-like activity by increasing the electron density of the Fe-N active center, meanwhile, the tailored bandgap significantly enhances the full-spectrum absorption, especially in the near-infrared region (NIR). Consequently, a light-enhanced N-doped BiFeO3 nanozyme has been engineered to generate excessive reactive oxygen species (14.63-fold in total) for pollutants degradation with recyclable capacity, 94.27% for Methylene Blue and over 60% for multiple antibiotics. This study underscores the efficacy of fine-tuning the electronic structure in enhancing the catalytic performance of nanozymes for organic pollutants removing.

W single-atom mediated singlet oxygen formation on carbon nitride for powerful photocatalytic abatement of organic pollutants

Active single-atom W anchoring on graphitic carbon nitride (g-C3N4) with interplanar four-coordination with N was achieved via a microwave hydrothermal process followed by thermal polymerization. The optimal monoatomic W incorporated g-C3N4 (W-CN) catalyst exhibited a high photocatalytic activity toward a wide range of pharmaceutical and personal care products (PPCPs). The anchoring of W single atom narrowed the energy-band, negatively shifted the conduction band of g-C3N4, and promoted the charge transfer and photogenerated carrier separation. Moreover, W single-atom intercalation obviously favored the formation of singlet oxygen (1O2), as validated by the active species capture test and density functional theory (DFT) calculation, which played an important role in the photocatalytic degradation of PPCPs. The treatment of actual wastewater, toxicity assessment and hemp-pea-growth experiments further showed that the W-CN photocatalyst could effectively degrade the organic pollutants and reduce their poisonousness in the water environment. This work offers a facile route to obtain reactive g-C3N4 with single-metal active sites and some insights into its activity enhancement for the abatement of organic pollutant-containing wastewater.

Highly selective regulation of non-radical and radical mechanisms by Co cubic assembly catalysts for peroxymonosulfate activation

Peroxymonosulfate (PMS) activation on efficient catalysts is a promising strategy to produce sulfate radical (SO4−) and singlet oxygen (1O2) for the degradation of refractory organic pollutants. It is a great challenge to selectively generate these two reactive oxygen species, and the regulation mechanism from non-radical to radical pathway and vice versa is not well established. Here, we report a strategy to regulate the activation mechanism of PMS for the selective generation of SO4− and 1O2 with 100 % efficiency by sulfur-doped cobalt cubic assembly catalysts that was derived from the Co-Co Prussian blue analog precursor. This catalyst showed superior catalytic performance in activating PMS with normalized reaction rate increased by 87 times that of the commercial Co3O4 nanoparticles and had much lower activation energy barrier for the degradation of organic pollutant (e.g., p-chlorophenol) (18.32 kJ⋅mol−1). Experimental and theoretical calculation results revealed that S doping can regulate the electronic structure of Co active centers, which alters the direction of electron transfer between catalyst and PMS. This catalyst showed a strong tolerance to common organic compounds and anions in water, wide environmental applicability, and performed well in different real-water systems. This study provides new opportunities for the development of metal catalyst with metal-organic frameworks structure and good self-regeneration ability geared specifically towards PMS-based advanced oxidation processes applied for water remediation.

Atmospheric bulk depositions: state-of-the-art and European legislative framework with focus on Italy.

The determination of total atmospheric deposition (bulk) is an essential tool to assess the state of environmental contamination and the consequent exposure of the population to persistent organic pollutants (POPs) through the intake of contaminated food. Over the past 20years, international authorities and the European Union through various pieces of legislation have emphasised the importance of conducting monitoring and studies on depositions to better understand their impact on the environment and human health without setting reference values. Despite the absence of such values, several European countries, through national laws, have adopted limit values and/or guideline values for the deposition fluxes of some organic (dioxins, furans, polychlorinated biphenyls and polycyclic aromatic hydrocarbons) and inorganic persistent pollutants (metals). The aim of this review is both to summarise the present European legislation on depositions both to discuss the different legislations adopted by the various member states. Furthermore, a focus of this paper will be dedicated to the Italian legislation, where there is currently no specific guideline values for POPs in atmospheric deposition. In any case, some national authorities in Italy, such as the National Institute of Health (ISS) and the Regional Environmental Protection Agencies (ARPA), have conducted numerous monitoring activities on depositions, providing the scientific community and policymakers with numerous data on which to establish national reference values.

Advancing nanoarchitectures of 2D WO3/MXene photoanode for enhanced photoelectrocatalytic oxidation of phenol and arsenic in synthetic wastewater

The photoelectrocatalytic advanced oxidation process (PEAOP) necessitates high-performing and stable photoanodes for the effective oxidation of complex pollutants in industrial wastewater. This study presents the construction of 2D WO3/MXene heteronanostructures for the development of efficient and stable photoanode. The WO3/MXene heterostructure features well-ordered WO3 photoactive sites anchored on micron-sized MXene sheets, providing an increased visible light active catalytic surface area and enhanced electrocatalytic activities for pollutant oxidation. Phenol, a highly toxic compound, was completely oxidized at an applied potential of 0.8 V vs. RHE under visible light irradiation. Systematic optimization of operational conditions for the photoelectrocatalytic oxidation of phenol was conducted. The phenol oxidation mechanism was elucidated via high-performance liquid chromatography (HPLC) analysis and the identification of intermediate compounds. Additionally, a mixed model of phenol and arsenic (III) in polluted water demonstrated the capability of WO3/MXene photoanode for the simultaneous oxidation of both organic and inorganic pollutants, achieving complete conversion of phenol and As(III) to non-toxic As(V). The WO3/MXene photoanode facilitated water oxidation, generating a substantial amount of O2•– and •OH oxidative species, which are crucial for the concurrent oxidation of phenol and arsenic. Recyclability tests demonstrated a 99% retention of performance, confirming the WO3/MXene photoanode's suitability for long-term operation in PEAOPs. The findings suggest that integrating WO3/MXene photoanodes into water purification systems can enhance economic feasibility, reduce energy consumption, and improve efficiency. This PEAOP offers a viable solution to the critical issue of heavy metal and organic chemical pollution in various water bodies, given its scalability and ability to preserve ecosystems while conserving clean water resources.

Mechanisms of colon toxicity induced by long-term perfluorooctanoic acid exposure in mice

Perfluorooctanoic acid (PFOA), a persistent organic pollutant known for its chemical stability, is widely dispersed in the environment, posing significant health risks to mammals through various exposure routes such as ingestion, inhalation, and dermal contact. In this study, mice were exposed to PFOA (0, 0.2, 2 mg/L) through drinking water for 180 days to investigate its toxic effects on the colon. We identified differentially expressed genes through RNA sequencing and validated the impact of PFOA on the expression of these genes in colon tissue. Our findings revealed that long-term exposure to PFOA caused inflammatory bowel disease (IBD)-like damage to the mouse colon. We found PFOA could induce damage to the intestinal barrier. Inhibition of the Wnt signaling pathway following PFOA exposure results in impaired stem cell function in the colon of mice. Furthermore, PFOA activated the PPAR signaling pathway, disrupting cellular lipid metabolism in colon tissues. Additionally, PFOA induced inflammatory responses in colon tissue, facilitating NLR family, pyrin domain containing 3 (NLRP3) inflammasome activation and cell apoptosis. This study offers a thorough understanding of the mechanisms responsible for the damage to mouse colon tissue resulting from long-term exposure to PFOA.

Temporal variations in dissolved organic matter properties in a eutrophic lake under water dilution and aquatic plant litter decomposition: A simulated microcosm study revealing the environmental and microbial driving factors

Dilution by importing external clean water and restoration of aquatic vegetation are widely applied strategies for improving water quality of eutrophic lakes, while the influence of dilution or aquatic plant litter decomposition on dissolved organic matter (DOM) properties, which is closely associated with the health of aquatic ecosystems, is rarely known. In this study, the temporal variations of DOM properties in the overlying water of a eutrophic lake (Yilong lake in Yunnan, southwest China) under water dilution and aquatic plant litter decomposition were comparatively investigated via a simulated microcosm study using in situ samples. The results showed that water dilution reduced DOM concentration and bioavailability in the overlying water in a short term (about 45 d), and increased DOM humification, but such effect diminished over time. DOM concentration increased substantially during aquatic plant litter decomposition, and reed litter released much more amounts of DOM than that of cattail litter, which dominated by protein-like substances and characterized by high bioavailability and low humification degree. Nutrient (available phosphorus (AP), NH4+-N and TN) contents in the sediment indirectly affected DOM properties by remarkably influencing microbial community compositions and enzyme activities. The strong correlations between the relative abundances of dominant genera Bacillus and Clostridium and concentrations of DOM components implied the important roles of these taxa in DOM transformations. Our findings highlighted the effects and potential mechanisms of dilution and aquatic plant litter decomposition on DOM properties in eutrophic water bodies, and the necessity of proper water diversion and plant litter harvest to reduce endogenous organic pollution in lakes.

Estimating Octanol-Water Partition Coefficients of Novel Brominated Flame Retardants by Reversed-Phase High-Performance Liquid Chromatography and Computational Models.

Legacy brominated flame retardants, including polybrominated diphenyl ethers (PBDEs), have been classified as persistent organic pollutants and replaced with novel brominated flame retardants (NBFRs). The octanol-water partition coefficients (log KOW) of NBFRs have been computationally estimated, but the log KOW values provided by these methods can differ by 1 to 3 orders of magnitude. Given the importance of this parameter in fate and toxicity models, we indirectly measured the log KOW values of eight NBFRs by their capacity factor (k') on a reversed-phase high-performance liquid chromatography (HPLC) C18 column by isocratic elution and compared these measured values with those estimated by nine computational models. Log KOW values were obtained for the NBFRs 1,2-bis(2,4,6-tribromophenoxy) ethane, pentabromobenzene, pentabromoethylbenzene, pentabromotoluene, 2-ethylhexyl 2,3,4,5-tetrabromobenzoate, allyl 2,4,6-tribromophenylether, 2,3-dibromopropyl-2,4,6-tribromophenyl ether, and bis(2-ethylhexyl) tetrabromophthalate. A training set of phthalates, polychlorinated biphenyls, PBDEs, and halogenated benzenes were chosen to obtain the log k'-log KOW calibration for the NBFRs. The computational models KowWIN, XLogP3, EAS-E Suite, COSMOtherm, DirectML, and Abraham polyparameter linear free energy relationships all predicted the log KOW values of the calibration compounds to within 1 order of magnitude without significant bias. The median of these models predicted log KOW values for the calibration compounds that were close to those known in the literature with root mean square error (RMSE) = 0.224 and for the NBFRs that were close to those measured by HPLC (RMSE = 0.334). Environ Toxicol Chem 2024;00:1-10. © 2024 SETAC.

Effects of polystyrene microplastics on the extracellular and intracellular dissolved organic matter released by Skeletonema costatum using a novel in situ method

Microplastics (MPs) affect the physicochemical algal-dissolved organic matter properties, indirectly influencing the environmental behavior of contaminants including persistent organic pollutants and heavy metals. Limited research is available on the roles played by intracellular- and extracellular-dissolved organic matter (I-DOM and E-DOM) in the processes that affect the environmental behavior of contaminants. Furthermore, the effects of MPs on the production of I-DOM and E-DOM, as well as their environmental behaviors, remain uncertain. A critical issue lies in the challenge of quantitatively identifying I-DOM and E-DOM in situ. In this work, a new fluorescence ratio method was developed and applied to in situ examine the impacts of polystyrene (PS) MPs (50, 500 nm, and 5 μm) on the I-DOM and E-DOM released by Skeletonema costatum (S. costatum). The experimental results indicated that the detection limits were 0.06 mg L−1, with the respective minimum detectable proportions being 2% for both E-DOM and I-DOM. The suppressive effects of 10–50 mg L−1 of 50 and 500 nm PS MPs on the cell proliferation of S. costatum and the E-DOM secretion were most pronounced on day 6. And the rates of suppression of E-DOM secretion were 10.1%−18.2% and 4.2%−13.9%, respectively. The exposure of algal cells to 50 mg L−1 of 50 and 500 nm PS MPs led to cell rupture and the leakage of I-DOM on day 6. This suggests that the developed method in the laboratory could offer a promising approach for studying the generation of E-DOM and I-DOM in situ, as well as their environmental behaviors affected by MPs.

Biochar with root pore channels loaded copper cobalt bimetallic metal organic framework for effective peroxomonosulfate activation to degrade organic pollutants

Biochar (BC) with root pore channel structure was used as the carrier, and bimetallic organic framework (CuCo-MOF) as the main active site. The CuCo-MOF was successfully dispersed in the internal channels of BC by in situ reaction, forming a composite catalyst (BC/CuCo-MOF(10%)) with unique reaction channels. The degradation efficiency of ciprofloxacin (20mg/L) in only 25min was 96.4%, and its catalytic performance was superior to that of the single BC and CuCo-MOF. On the one hand, abundant CuCo-MOF reaction sites were distributed in the relatively closed porous reaction channel of BC, which accelerated the mass transfer process (short mass transfer distance) during the CIP degradation process and improved the CIP degradation performance. On the other hand, highly conductive BC facilitates electron transfer between Cu2+/Cu+ species and HSO5-, accelerating the redox cycle of Cu2+/Cu+, thereby improving catalytic activity. Besides, the composite catalyst was still able to achieve a degradation efficiency of 87.6% for CIP after five cyclic degradation experiments. The concentrations of Cu and Co ions in the reaction solution were only 0.04 and 0.03mg/L. Therefore, the composites have excellent catalytic activity and stability. Both non-radical 1O2 and radicals (SO4·- and ·OH) were involved in the reaction, and the non-radical 1O2 pathway played a dominant role in the CIP degradation process.

Stabilizing atomic Co on 2D ordered mesoporous carbon sandwiched MXene for peroxymonosulfate activation: Enhanced performance and electron-transfer mechanism

In this study, a dual-carrier catalyst is designed for efficient Fenton-like catalysis following non-radical electron-transfer process (ETP). By using 2D mesoporous carbon sandwiched MXene (MCSMx) nanosheets as dual functional substrates, Co single atoms (Co-SA) were confined within MCSMx (CoSA/MCSMx), in which the coordinated Co-N4 sites in highly ordered mesoporous channels (~10nm) facilitated the adsorption of peroxymonosulfate (PMS), while the excellent conductivity of MXene as the substrate enhanced the transport of electron. The unique design of Co-SA anchored on dual-carrier endows the CoSA/MCSMx with excellent PMS adsorption and rapid electron transfer, achieved nearly 100% ETP pathway for bisphenol A (BPA) removal and highly selective degradation towards electron-rich pollutants. Moreover, the ETP-induced polymerization transfer reaction of BPA was discovered in the catalytic system, resulting in total organic carbon (TOC) removal ratios of up to 72%. This work provides new insights into the rational design ETP-based systems for the efficient removal of organic pollutants.

Status and future scope of algal biomass-based remediation for various environmental contaminants

Algal biomass has attracted a lot of attention as a sustainable and efficient technique for remediating a variety of environmental pollutants owing to its unique metabolic properties and environmental tolerance. The remediation potential of algal biomass for a wide range of contaminants, including heavy metals, organic pollutants, nutrients, and new contaminants, are examined in this review. Through processes including bioaccumulation, biosorption, and biodegradation, algae show exceptional capacities to absorb, metabolize, and sequester contaminants, thereby mitigating environmental contamination in aquatic and terrestrial ecosystems. Furthermore, significant developments in algal biotechnology and growing techniques have made it possible to produce biomass with higher productivity and can remove pollutants with greater efficiency. This has encouraged the use of algae in wastewater treatment, industrial effluent cleanup, and ecological restoration projects. Nevertheless, the integration of algal systems with the current wastewater treatment infrastructure offers hope for environmentally acceptable and reasonably priced solutions to the environmental pollution. Through this review, we have highlighted the crucial part that algal biomass plays in sustainable environmental stewardship and also the necessity for continued multidisciplinary research to fully realize its potential in addressing global environmental pollution concerns.

Effect of bariatric surgery in the body burden of persistent and non-persistent pollutants: longitudinal study in a cohort of morbidly obese patients

IntroductionObesity is a pathological state that involves the dysregulation of different metabolic pathways and adipose tissue cells, constituting a risk factor for the development of other diseases. Bariatric surgery is the most effective treatment. The study of the behavior of pollutants in situations of extreme weight loss can provide biomonitoring information and tools to manage diseases of environmental etiology.AimTo determine the prevalence of serum persistent and non-persistent pollutants in obese patients subjected to bariatric surgery and analyze the impact of sociodemographic variables on these changes.MethodsGC-MS/MS and UHPLC-MS/MS were utilized to determine the detection rates and concentrations of 353 compounds, including persistent organic pollutants (POPs), pesticides, pharmaceuticals, and rodenticide, in serum samples of 59 obese patients before and after undergoing bariatric surgery.ResultsDetection rates of p,p’-DDE, HCB, β-HCH, naphthalene, phenanthrene and PCB congeners 138, 153 and 180 significantly increased due to surgery-induced weight loss. Serum levels of p,p’-DDE, PCB-138, PCB-153 and PCB-180 also increased after surgery. Correlations between naphthalene levels, weight loss, variation of total lipids and time after surgery were found. Additionally, correlations were observed between concentrations of PCB-138 and weight loss, and between phenanthrene levels and reduction of total lipids. No statistically significant differences were observed for other groups of contaminants, pharmaceuticals and other chemicals included in the quantification methods.ConclusionsIncrement of POPs was observed after bariatric surgery. Serum concentrations of POPs after surgery were influenced by adiposity-related variables. Although biomonitoring studies show a decreasing tendency of exposure, rapid weight loss leads to an increase of circulating POPs. Further research on the interplay between adipose tissue, POPs and peripheral organs is required.

Determination of persistent organic pollutants in urban and peri-urban wastewater sludge: environmental and carcinogenic human risk assessment in the case of land application.

The management of digested sludge derived from treatment water plants is a problem worldwide due to the possible transfer of contamination from sludge to amended soil and, in turn, to humans. Within this work, through a chemometric experimental design, a robust GC-MS method for the simultaneous determination of two classes of micropollutants of concern (polycyclic aromatic hydrocarbons-PAHs-and polychlorinated biphenyls-PCBs-including dioxin-like compounds) was developed using microwave-assisted extraction (MAE). The method, which showed interesting greenness features in compliance with the 12 principles of Green Chemistry, allowed PCB and PAH extraction with recoveries higher than 75% (RSD < 14%) with method detection limits between 4.6 and 11.5µgkg-1 (PAHs) and between 6.9 and 13.7µgkg-1 (PCBs), without preconcentration. The matrix effect was below 20%. The validated protocol allowed the characterization of two digested sludges sampled in an urban and a peri-urban district, representative models of two scenarios of different anthropic impacts. This study highlighted higher contamination for the sludge derived from the urban area, accounted for by the 4-ring PAHs. In addition, since carcinogenic PAHs were detected, the environmental risk (by mean of the comparison of predicted vs predicted no-effect concentrations) and the carcinogenic human risk from dermal contact (through the calculation of the adsorbed lifetime average daily dose) were assessed in the case of soils amended with the sludges considered, pointing out that the measured concentrations do not pose a risk.

Exposure to Synthetic Endocrine-Disrupting Chemicals in Relation to Maternal and Fetal Sex Steroid Hormones: A Scoping Review.

Many synthetic endocrine-disrupting chemicals (EDCs) are ubiquitous in the environment and highly detected among pregnant people. These chemicals may disrupt maternal and/or fetal sex steroid hormones, which are critical to pregnancy maintenance and fetal development. Here, we review the epidemiological literature examining prenatal exposure to common synthetic EDCs in relation to maternal and fetal sex steroid hormones. We performed a literature search using PubMed, SCOPUS, and Embase, ultimately identifying 29 articles for full review. Phenols, parabens, and persistent organic pollutants generally showed inverse associations with androgens, estrogens, and progesterone. Phthalates and per-and polyfluoroalkyl substances tended to be inversely associated with progesterone, while evidence regarding androgens and estrogens was mixed. Inconsistent, but noteworthy, differences by fetal sex and timing of exposure/outcome were observed. Overall, the literature suggests EDCs may disrupt maternal and fetal sex steroid activity, though findings are mixed. Given the pervasive, high-volume production of these synthetic chemicals and the critical functions sex steroid hormones play during gestation, additional research is warranted.

Ultrasonic disintegration of municipal sludge: fundamental mechanisms, process intensification and industrial sono-reactors.

Sludge disintegration is an environmental and industrial challenge that requires intensive research and technological development. Sludge contains a complex structure with a high yield of various chemical and biological compounds. Anaerobic digestion is the most used process for sludge disintegration to produce biogas, detoxify the sludge, and generate biosolids that can be used in agricultural. Biological cell lysis is the rate-limiting cell lysis. This review discusses the application of sonolysis as a sludge pretreatment for enhanced anaerobic digestion via three combined processes: thermal destruction, hydrochemical shear forces, and radical oxidation. The mechanistic pathways of sono-pretreatment to enhance biogas, sludge-enhanced dewatering, activation of filamentous bacteria, oxidation of organic pollutants, release of heavy metals, reduction of bulking and foaming sludge, and boosting ammonia-oxidizing bacteria activity are discussed in this report. The combination of ultrasound with other chemical processes, such as Fenton and cation binding agents for enhanced sludge disintegration, is discussed. Finally, we reviewed the most common large-scale sono-reactors available on the market for sludge disintegration.

Exploring the Anti-Corrosion, Photocatalytic, and Adsorptive Functionalities of Biogenically Synthesized Zinc Oxide Nanoparticles

This study reported the synthesis of ZnO nanoparticles (ZnO NPs) using Cucurbita pepo L. seed extract and explored their multifunctional properties such as anti-corrosion, photocatalytic, and adsorption capabilities. The synthesized ZnO NPs were characterized by Fourier-transform infrared spectroscopy (FTIR) to identify their functional groups, thermogravimetric analysis (TGA) to assess their thermal stability, transmission electron microscopy (TEM), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) to determine their size, morphology, and elemental composition. The characterization of biofabricated ZnO NPs revealed an average particle size of 32.88 nm; however, SEM displayed a tendency for the particles to agglomerate. Furthermore, the X-ray diffraction (XRD) and EDX analysis confirmed the NPs as ZnO, matching patterns reported in the literature. In this study, the potential of the biogenic ZnO NPs was explored for multifunctional applications. Zinc oxide nanoparticles exhibited a higher capacity for adsorbing hydrogen sulfide (H2S) compared to bulk zinc oxide, mostly because of their larger surface area. In addition, electrochemical studies demonstrated a substantial enhancement in the corrosion resistance of mild steel in a 1.0 M HCl solution. ZnO NPs also demonstrated remarkable photodegradation effectiveness, reducing 75% of methyl orange in 60 min under sun-light irradiation. This implies that they could be used to remediate organic pollutants (organic dyes) from wastewater.