Formation Of By-products Research Articles

Optimizing Therapeutics for Intratumoral Cancer Treatments: Antiproliferative Vanadium Complexes in Glioblastoma

Glioblastoma, an aggressive cancer, is difficult to treat due to its location, late detection, drug resistance, and poor absorption of chemotherapeutics. Intratumoral drug administration offers a promising potential treatment alternative with localized delivery and minimal systemic toxicity. Vanadium(V) coordination complexes, incorporating Schiff base and catecholate ligands, have shown effects as antiproliferative agents with tunable efficacy and reactivity, stability, steric bulk, hydrophobicity, uptake, and toxicity optimized for the intratumoral administration vehicle. A new series of oxovanadium(V) Schiff base–catecholate complexes were synthesized and characterized using nuclear magnetic resonance (NMR), UV-Vis, and infrared spectroscopy and mass spectrometry. Stability under physiological conditions was assessed via UV-Vis spectroscopy, and the antiproliferative activity was evaluated in T98G glioblastoma and SVG p12 normal glial cells using viability assays. The newly synthesized [VO(3-tBuHSHED)(TIPCAT)] complex was more stable (t1/2 ~ 4.5 h) and had strong antiproliferative activity (IC50 ~ 1.5 µM), comparing favorably with the current lead compound, [VO(HSHED)(DTB)]. The structural modifications enhanced stability, hydrophobicity, and steric bulk through substitution with iso-propyl and tert-butyl groups. The improved properties were attributed to steric hindrance associated with the new Schiff base and catecholato ligands, as well as the formation of non-toxic byproducts upon degradation. The [VO(3-tBuHSHED)(TIPCAT)] complex emerges as a promising candidate for glioblastoma therapy by demonstrating enhanced stability and a greater selectivity, which highlights the role of strategic ligand design in developing localized therapies for the treatment of resistant cancers. In reporting the new class of compounds effective against T98G glioblastoma cells, we describe the generally desirable properties that potential drugs being developed for intratumoral administration should have.

Metal-Organic Frameworks with Phosphonate Monoester Linkers for Catalytic C(sp2)-H Borylation of Alkenes.

An isoreticular metal-organic framework (MOF) series was constructed from nickel or cobalt nodes, phosphonate monoester, and bipyridine linkers. The cobalt-containing MOFs were found to catalyze the dehydrogenative C-H borylation of alkenes under mild conditions. This process selectively generates vinyl boronate without the formation of alkyl boronate byproducts and is insensitive to air, enabling large-scale preparation of the target products with isolated yields of over 80%.

Nanoconfinement-Enabled Resistance to Water Matrix Components for Selective Degradation of Micropollutants.

Despite recent substantial advances in water treatment, the ability to selectively degrade trace micropollutants in real waters with complex matrix components remains a grand challenge. Here we report rational crafting of graphene oxide (GO)-wrapped defective TiO2 composite catalysts that creates nanoscopic confinement over the TiO2 surface within GO, thereby enabling the selective degradation of micropollutants through effectively excluding natural organic matter (NOM) and anions from the nanoconfined catalytic sites. In contrast to unconfined counterparts, the nanoconfined composite catalysts retain high degradation efficiency when exposed to various concentrations of NOM and anions, even in real water samples. Oxygen vacancies in TiO2 promote electron separation and oxygen adsorption, leading to a 4.9-fold increase in hydroxyl radical concentration within the nanoconfined space compared to the bulk solution. In-situ X-ray photoemission spectroscopy and Raman spectroscopy unveil the nanoconfined catalytic sites on the TiO2 surface, where micropollutants smaller than the pores of GO are effectively degraded, while NOM with a larger size is excluded by GO. Furthermore, the formation of toxic disinfection byproducts is well controlled due to the exclusion of NOM. This work provides a simple yet viable strategy for designing 2D material-wrapped catalysts to selectively degrade target micropollutants in complex real waters.

Involvement of inorganic nitrogen species (NOX- (x=2, 3)) in the degradation of organic contaminants in environmental waters via UV irradiation or chemical oxidation: A dual-edged approach.

OH-mediated advanced oxidation processes (AOPs) are widely used in wastewater treatment and drinking water purification. Recently, an increasing number of studies have indicated that common inorganic nitrogen ions can efficiently generate •OH under UV irradiation, demonstrating strong performance in the degradation of various contaminants. Conversely, the presence of inorganic nitrogen ions in UV or other oxidation processes dramatically increases the yield of toxic nitro (so)-aromatic products and the formation potential of nitrogenous disinfection by-products with high genotoxicity and cytotoxicity. This suggests that the presence of inorganic nitrogen ions in water and wastewater treatment is a 'double-edged sword', offering both benefits and potential harms. Herein, we systematically review the dual roles of inorganic nitrogen ions in contaminant degradation and nitrogenous by-product formation. First, the degradation kinetics of the UV/NOx- (x=2, 3) and oxidant/NO2- processes are summarized for various contaminants. The pseudo-first-order rate constants (kpfo) of contaminant degradation in the UV/NO3- system range from 10-3 to 10-1min-1, while those in the UV/NO2- and peracetic acid/NO2- system vary from 10-3 to 102min-1 and 10-2 to 10-1min-1, respectively. Moreover, the properties of the water matrix (i.e., pH and O2) play a crucial role in the degradation kinetics by influencing the concentrations and distribution of reactive nitrogen species (RNS), as well as the morphology of the contaminants. Second, this review provides a general overview of the sources and properties of key RNS, including •NO2, ONOO-/ONOOH, and free nitrous acid (FNA), which are closely associated with the formation of nitrogenous by-products. Finally, the formation pathways of nitro (so)-aromatic products and nitrogenous disinfection by-products are discussed. These pathways are driven either by RNS alone or by the combination of RNS with reactive oxygen species (ROS).

Recent Advances in Electrolytes for Nonaqueous Lithium-Oxygen Batteries.

This paper emphasizes the critical role of electrolyte selection in enhancing the electrochemical performance of nonaqueous Li-O2 batteries (LOBs). It provides a comprehensive overview of various electrolyte types and their effects on the electrochemical performance for LOBs, offering insights for future electrolyte screening and design. Despite recent advancements, current electrolyte systems exhibit inadequate stability, necessitating the urgent quest for an ideal nonaqueous electrolyte. Such an electrolyte should demonstrate superior physicochemical and electrochemical stability, particularly in the presence of superoxide radicals (O2 -), with high oxygen solubility, rapid diffusion rates, and the capability to form a stable SEI film on the lithium anode. The paper advocates for further research in three key areas: the selection of suitable electrolytes, the construction of stable electrode/electrolyte interfaces, and the mechanistic exploration of byproduct formation. Addressing these challenges will advance the development of electrolyte technology for LOBs, paving the way for its commercialization and broad application.

Metabolic Engineering of Escherichia coli BL21(DE3) for 2'-Fucosyllactose Synthesis in a Higher Productivity.

2'-Fucosyllactose (2'-FL) is the most abundant human milk oligosaccharides (HMOs). 2'-FL exhibits great benefits for infant health, such as preventing infantile diarrhea and promoting the growth of intestinal probiotics. The microbial cell factory technique has shown promise for the massive production of 2'-FL. Here, we aimed to construct a recombinant E. coli BL21(DE3) strain for the hyperproduction of 2'-FL. Initially, multicopy genomic integration and expression of the lactose permease gene lacY reduced the formation of byproducts. Furthermore, a more efficient Shine-Dalgarno sequence was used to replace the wild-type sequence in the manC-manB and gmd-wcaG gene clusters, which significantly increased the 2'-FL titer. Based on these results, we overexpressed the sugar efflux transporter SetA and knocked out the pgi gene. This further improved 2'-FL synthesis when glycerol was used as the sole carbon source. Finally, a new α-1,2-fucosyltransferase was identified in Neisseria sp., which exhibited a higher capacity for 2'-FL production. Fed-batch fermentation produced 141.27 g/L 2'-FL in 45 h with a productivity of 3.14 g/L × h. This productivity rate achieved the highest recorded 2'-FL levels, indicating the potential of engineered E. coli BL21 (DE3) strains for use in the industrial production of 2'-FL.

Biocatalytic Hydrogenation of Biomass-Derived Furan Aldehydes to Alcohols.

The biomass-derived furan aldehydes furfural (FF) and 5-hydroxymethylfurfural (HMF) are versatile platform chemicals used to produce various value-added chemicals through further valorization processes. Selectively reducing C═O in FF and HMF molecules to form furfuryl alcohol (FAL) and 2,5-bis(hydroxymethyl)furan (BHMF), represents an important research field in upgrading biomass-based furan compounds. Currently, the reduction of furan aldehydes to furan alcohols through chemical transformation often leads to unavoidable environmental issues and the formation of potential byproducts. Biocatalysis has demonstrated expanded applications in converting biomass-derived furan aldehydes into a diverse array of value-added chemicals. This process exhibits significant potential in organic synthesis and biotechnology due to its green and sustainable properties. The biocatalytic reduction of FF and HMF represents an especially important route for the selective synthesis of FAL and BHMF. This review discusses recent progress in the biosynthesis of FAL and BHMF from biomass-derived FF and HMF through biocatalytic processes. Recently discovered enzymes and whole cells used as biocatalysts for the production of furan alcohols are summarized. In addition, chemoenzymatic cascades for synthesizing furan alcohols from biomass hydrolysate and raw biomass materials are also discussed.

The Aging Chemistry of Perovskite Precursor Solutions.

A significant barrier to the commercialization of solution-processed perovskite solar cells (PSCs) is the chemical instability of the components in precursor solutions under ambient conditions. This instability leads to solution aging, which subsequently diminishes the quality and reproducibility of the resulting PSCs. Inspired by recent published works, which focused on the deprotonation of organic cations, the oxidation of iodide, and the formation of undesired byproducts, we here systematically summarize and provide an outlook on the research directions and perspectives of the origin of precursor solution aging and countermeasures, such as using stabilizing additives, redox shuttles, Schiff base reactions, and green solvents. We are aiming to provide insight into potential paths for achieving reproducible and efficient PSCs with high operational stability.

Technological assessment of trihalomethanes in drinking water supplying the city of Sidi Bel Abbes (western Algeria)

Trihalomethanes are a group of chemical compounds that can contaminate drinking water. THMs are formed when the chlorine used to disinfect the water reacts with the natural organic matter present in the water. Mainly, their formation depends on pH, free residual chlorine, water temperature, and the concentration of natural organic matter.The objective of this work is to determine the impact of certain physicochemical parameters on the formation of trihalomethanes in the drinking water supplying the city of Sidi Bel Abbes.Physicochemical analyses of drinking water from three distribution networks supplying the city of Sidi Bel Abbes revealed that the pH values are around 7 and the temperature does not exceed 20°C. The analysis of organic matter in the collected samples shows variable results between areas, with organic matter concentrations in area 1 being slightly higher than those in area 2. The average concentrations of organic matter recorded in area 3 are lower compared to those in the other two sampling areas. Our results show that the free residual chlorine in the network directly contributes to the formation of disinfection by-products. This study aims to enhance knowledge of the spatio-temporal formation of trihalomethanes in drinking water distribution reservoirs.

Functional characterization and protein engineering of a O-methyltransferase involved in benzylisoquinoline alkaloid biosynthesis of Stephania tetrandra.

Benzylisoquinoline alkaloids (BIAs) are the primary active components of Stephania tetrandra. However, the molecular mechanisms underlying BIA biosynthesis in S. tetrandra remain poorly understood. Here, we reported the isolation and characterization of a novel O-methyltransferase, designated as St7OMT1, from S. tetrandra. St7OMT1 exhibited strict substrate specificity and regioselectivity, catalyzing the conversion of (S)-coclaurine to norarmepavine at the C7 position. Optimal enzymatic activity of St7OMT1 was detected at 30 °C and pH 6.0 in NaAc-HAc buffer, with kinetic parameters of Km = 163.16 μM and kcat = 0.00005 s-1. Site-directed mutagenesis identified three critical residues Ala118, Gln121 and Arg151 that significantly influenced catalytic activity and substrate selectivity. A triple mutant (A118V-Q121L-R151L) was engineered, exhibiting a 5.97-fold increase in catalytic activity compared to the wild-type enzyme. Molecular dynamics simulations revealed that the enhanced catalytic activity resulted from an expanded substrate access tunnel and binding pocket, as well as improved non-covalent interactions between the enzyme and substrate. This study provides a promising St7OMT1 variant for the BIA biosynthesis with reduced by-product formation and offers valuable insights into protein engineering strategies to enhance O-methyltransferase activity in plants.

Stable isotope labelling to elucidate ring cleavage mechanisms of disinfection by-product formation during chlorination of phenols

Stable isotope labelling to elucidate ring cleavage mechanisms of disinfection by-product formation during chlorination of phenols

Reducing the Formation of Toxic Byproducts During the Photochemical Release of Epinephrine.

Engineered light-sensitive molecules offer a sophisticated toolkit for the manipulation of biological systems with both spatial and temporal precision. Notably, artificial "caged" compounds can activate specific receptors solely in response to light exposure. However, the uncaging process can lead to the formation of potentially harmful byproducts. For example, the photochemical release of adrenaline (epinephrine) is accompanied by the formation of adrenochrome, which has neuro- and cardiotoxic effects. To investigate this effect in detail, we synthesized and compared two "caged" epinephrine analogs. The first was a classical compound featuring an ortho-nitrobenzyl protecting group attached to the amino group of epinephrine. The second analog retained the ortho-nitrobenzyl group but included an additional carbamate linker. The photolysis of both compounds was conducted under identical conditions, and the resulting products were analyzed using UV-Vis spectroscopy, chromatography, and NMR techniques. Surprisingly, while the classical compound led to the formation of adrenochrome, the carbamate-type caged epinephrine did not produce this byproduct, resulting in the clean release of the active substance. Subsequently, we assessed the novel compound in an in vitro platelet activation assay. The results demonstrated that the uncaging of epinephrine significantly enhances platelet activation, making it a valuable tool for advanced signaling studies.

Guarding Drinking Water Safety against Harmful Algal Blooms: Could UV/Cl2 Treatment Be the Answer?

Frequent and severe occurrences of harmful algal blooms increasingly threaten human health by the release of microcystins (MCs). Urgent attention is directed toward managing MCs, as evidenced by rising HAB-related do not drink/do not boil advisories due to unsafe MC levels in drinking water. UV/chlorine treatment, in which UV light is applied simultaneously with chlorine, showed early promise for effectively degrading MC-LR to values below the World Health Organization's guideline limits. Still, much is unknown regarding potential disinfection byproduct formation and associated toxicity, which can occur from the reaction of chlorine and other reactive species with MCs and algal and natural organic matter. To ensure UV/chlorine guarding drinking water for human consumption, the degradation and detoxification of four of the most problematic MC variants, namely, MC-LR, -RR, -YR, and -LA, which differ in amino acid substituents, were evaluated using UV/chlorine and compared to results from chlorination. Overall, UV/chlorine effectively enhanced MC degradation kinetics and generated less halogenated disinfection byproducts in the target analysis of 11 types of DBPs_C1-3 from 7 classes, total organic chlorine, and nontarget analysis revealing 35 higher molecular weight DBPs_C46-52, which maintained the MC structures. Reactivity and cytotoxicity changes varied based on the individual amino acid moieties within the cyclic heptapeptide structure common to all MCs. Analogous trends in MC reactivity were observed in degradation kinetics and mixed MC competition reactions, aligning with individual amino acid structure-reactivity. Cytotoxicity results indicated no significant unintended toxic consequences from MC_DBPs. Our results suggest that UV/chlorine treatment offers an efficient strategy for treating MCs in drinking water.

Rationally designed Cu(II) Schiff base metal complex anchored on NiFe2O4@chitosan: an efficient heterogeneous and magnetically retrievable hybrid nanocatalyst for the one-pot multi-component synthesis of bioactive 1-amidoalkyl-2-naphthols.

We reported, herein, the fabrication of a Cu(II) Schiff base metal complex, immobilized on chitosan surface coated on NiFe2O4 MNPs, intended as a novel heterogeneous and magnetically recyclable nanocatalyst, NiFe2O4@CS@CuSB. The synthesis process starts with the preparation of NiFe2O4 MNPs followed by coating with chitosan and then subsequent immobilization of the Cu(II) Schiff base metal complex on its surface. Through comprehensive characterization of the prepared nanocatalyst using FT-IR, PXRD, SEM, EDS, TEM, SAED, VSM, BET, XPS, and ICP-AES, the structure, surface morphology, elemental composition, and characteristics of the catalyst are revealed. For the evaluation of its catalytic activity, NiFe2O4@CS@CuSB, has been utilized as a potential nanocatalyst for the one-pot multicomponent organic synthesis of 1-amidoalkyl-2-naphthol scaffolds. A straightforward, effective, one-pot, and environmentally safe synthesis of 1-amidoalkyl-2-naphthol has been accomplished using a broad range of aldehydes, 2-naphthol, urea, or amide, demonstrating the catalyst's strong resistance to different functionalities. High yields of the intended products have been obtained without the formation of byproducts. A hot filtration test was employed to evaluate the heterogeneity of the solid nanocatalyst. With potential uses in medicinal chemistry, this novel catalyst presents a viable method for the effective production of bioactive molecules.

Degradation of levofloxacin by dielectric barrier discharge plasma/chlorine process: Roles of reactive species and control of chlorination disinfection byproducts.

In this study, a novel process of dielectric barrier discharge (DBD)/chlorine for levofloxacin (LEV) degradation was investigated. The combined system boosted the degradation efficiency of LEV from 77.8% to 97.5%, improved the reaction rate constant by 2.3 times, and reduced energy consumption by 64.5%. DBD/chlorine process was highly efficient for LEV degradation across a pH range of 3.3-10.8, with removal rates varying from 90.3% to 97.5%. The electron paramagnetic resonance and scavenging experiments demonstrated the generation of reactive oxygen species (ROS, including HO•, 1O2, and O2•-) and reactive chlorine species (RCS) in the DBD/chlorine system, with 1O2 in the nonradical pathway being crucial for LEV removal. Crucially, effective activation of chlorine not only encouraged the production of reactive species but also prevented the formation of disinfection by-products (DBPs), successfully controlling the ecotoxicity of the reaction system. DBD could activate chlorine to form chlorate and HO•, which in turn triggered the production of RCS. The comparison of the LEV degradation pathway was proposed with or without chlorine in the DBD process. Finally, the effects of different water quality and water bodies demonstrated the application prospects of the DBD/chlorine process. This work provided an efficient technique for the elimination of antibiotics by non-thermal plasma/chlorine.

Molecular-level insights into the degradation of dissolved organic matter from cyanobacteria-impacted water by electro-oxidation and electro-Fenton with carbon-based electrodes

Algal organic matter (AOM) originating from cyanobacteria-impacted reservoirs presents a significant risk to drinking water. Electrochemical oxidation is an emerging technology effective in AOM degradation. This study focuses on the elimination of AOM, including extracellular organic matter (EOM) and intracellular organic matter (IOM), extracted from Microcystis aeruginosa (MA). Electro-Fenton (EF) and electro-oxidation (EO) techniques were used, with a boron-doped diamond (BDD), a modified graphene-Fe2O3 (GFe) anode, and a graphite felt (GF) cathode. The results showed that BDD and GFe electrodes can effectively degrade AOM, particularly IOM, via EO and EF. BDD with high overpotential exhibited significant IOM degradation via EF, where dissolved organic carbon reduction reached up to 85%. In EO reactions, H2O2 generation by GFe-30 (obtained at the optimal ferric oxide to graphene ratio) is slightly higher than that in BDD, but it cannot fully transform into •OH in the EF process, which inhibits its AOM degradation capability. Furthermore, soluble microbial product-like substances and humics are more effectively degraded by EF and EO using either BDD or GFe. High-molecular weight (>103 Da) fractions, such as biopolymers and humic substances, are principally degraded by both EF and EO regardless of the BDD and GFe anode. This process leads to significant reductions in the haloacetic acids (HAAs) formation potential. EO and EF with GFe-30 are more effective in reducing specific disinfection by-product formation potential during IOM suspension degradation compared to BDD. In conclusion, GFe serves as a novel electrode material to replace BDD as a potent carbon-based anode when utilizing EO or EF treatments for effective AOM removal from cyanobacteria-infested water for drinking water treatment.

Electrocatalytic conversion of nitrate to ammonia on the oxygen vacancy engineering of zinc oxide for nitrogen recovery from nitrate-polluted surface water.

Nitrate pollution in surface water poses a significant threat to drinking water safety. The integration of electrocatalytic reduction reaction of nitrate (NO3RR) to ammonia with ammonia collection processes offers a sustainable approach to nitrogen recovery from nitrate-polluted surface water. However, the low catalytic activity of existing catalysts has resulted in excessive energy consumption for NO3RR. Herein, we developed a facile approach of electrochemical reduction to generate oxygen vacancy (Ov) on zinc oxide nanoparticles (ZnO1-x NPs) to enhance catalytic activity. The ZnO1-x NPs achieved a high NH3-N selectivity of 92.4% and NH3-N production rate of 1007.9 [Formula: see text] h-1 m-2 at -0.65V vs. RHE in 22.5mgL-1NO3--N, surpassing both pristine ZnO and the majority of catalysts reported in the literature. DFT calculations with in-situ Raman spectroscopy and ESR analysis revealed that the presence of Ov significantly increased the affinity for the NO3- (nitrate) and key intermediate of NO2- (nitrite). The strong adsorption of NO3- on Ov decreased the energy barrier of potential determining step (NO3- →∗NO3) from 0.49 to 0.1eV, boosting the reaction rate. Furthermore, the strong adsorption of NO2- on Ov prevented its escape from the active sites, thereby minimizing NO2- by-product formation and enhancing ammonia selectivity. Moreover, the NO3RR, when coupled with a membrane separation process, achieved a 100% nitrogen recycling efficiency with low energy consumption of 0.55 kWh molN-1 at a flow rate below 112mLmin-1 for the treatment of nitrate-polluted lake water. These results demonstrate that ZnO1-x NPs are a reliable catalytic material for NO₃RR, enabling the development of a sustainable technology for nitrogen recovery from nitrate-polluted surface water.

The sorption of algal organic matter by extracellular polymeric substances: Trade-offs in disinfection byproduct formation influenced by divalent ions.

Disinfection by-products (DBPs), formed from biofilm extracellular polymeric substances (EPS) and organic matter during regular disinfection practices in drinking water distribution systems, poses a potential threat to drinking water safety. However, the diverse DBP formations induced by the intertwined algal organic matter (AOM) and bacterial EPS remains elusive. In this study, we show substantial variations in EPS and DBP formation patterns driven by AOM biosorption with divalent ions (Ca2+ and Mg2+). Divalent ions in bulk water can significantly inhibit carbonaceous DBPs (C-DBPs) and nitrogenous DBPs (N-DBPs) formation. Mechanistically, divalent ions promote the complexation of negative charged groups and thus inhibit C-DBP formation, while the hindering chlorine substitution of hydrogen atoms on α‑carbon and amine groups reduces N-DBP formation. Conversely, Ca2+ and Mg2+ could facilitate biosorption processes that increased the yields of C-DBPs and N-DBPs. Both EPS and AOM provide halogenated reactive sites for DBP formation, exhibiting diverse aromatic substances and unsaturated (lignin and tannins) compounds. Our results highlight divalent ions acting as a fundamental driving force in DBP formation, suggesting the need for cautious monitoring of divalent ions in karst water.

Evaluation of MC-LR Removal by Sodium Hypochlorite Disinfection as Best Available Technology (BAT) for Algal Toxin Removal

Harmful cyanobacteria produce various toxic substances, among which microcystin is the most commonly detected toxin in water resources, with microcystin-LR(MC-LR) known to be the most toxic. For the removal of microcystin, sodium hypochlorite(NaOCl) disinfection is recognized as an effective best available technology(BAT) in water treatment facilities for MC-LR removal, within limits that minimize the formation of disinfection by-products. However, chlorine disinfection of microcystin is affected by various factors, including temperature and pH, with environmental factors such as the presence of organic matter in raw water potentially influencing the efficiency of microcystin removal. In this study, raw water was collected from the Nakdong River, and Intracellular Organic Matter(IOM) was extracted from algal cells. NaOCl was then added to both the IOM raw water and DI water to assess the chlorine disinfection rate of MC-LR removal and to analyze the pseudo-first-order reaction kinetics, evaluating the impact of organic matter in raw water on MC-LR chlorination. The results showed that the MC-LR removal rate in IOM by chlorine disinfection was a maximum of 17%, while the MC-LR removal in deionized water reached up to 99%. The pseudo-first-order reaction rate constants were 3.99×10<sup>-5</sup>s<sup>-1</sup> and 9.11×10<sup>-4</sup>s<sup>-1</sup> for IOM and deionized water, respectively, indicating that MC-LR removal in IOM was slower and had a lower removal rate compared to that in deionized water. This study demonstrates that chlorine disinfection is suitable as the BAT for algal toxin removal and highlights the need to reduce the amount of organic matter through pre-treatment before chlorine disinfection.

Radiolytic Elimination of Nabumetone from Aqueous Solution: Degradation Efficiency, and Degradants' Toxicity.

Advanced oxidation processes (AOPs), including ionizing radiation treatment, are increasingly recognized as an effective method for the degradation of pharmaceutical pollutants, including non-steroidal anti-inflammatory drugs (NSAIDs). Nabumetone (NAB), a widely used NSAID prodrug, poses an environmental risk due to its persistence in aquatic ecosystems and its potential toxicity to non-target organisms. In this study, the radiolytic degradation of NAB was investigated under different experimental conditions (dose rate, radical scavenging, pH, matrix effect), and the toxicity of its degradation products was evaluated. NAB was rapidly degraded at 300 Gy with prolonged irradiation. Mineralization of about 88% of NAB solutions was observed based on the evaluation of total organic carbon (TOC). The most efficient degradation of NAB occurred under N2O conditions, while it was retarded in the presence of thiourea. The water matrix components had a significant influence on the efficiency of degradation. In addition, the main degradation products were identified by LC-HRMS. Toxicity studies on different bacteria showed no significant impact of the NAB degradation products, while in silico predictive methods revealed their slightly increased toxicity compared to the parent compound, but considerably lower toxicity in comparison to its main active form 6-methoxy-2-naphthylacetic acid (MNA). Additionally, significantly lower toxicities are predicted for degradation products in N2O saturated solution. These results underline the importance of optimizing irradiation parameters for effective degradation and minimizing the formation of harmful by-products. Understanding all aspects of the AOP processes and the toxicological effects of the degradation products ensures effective mitigation of potential environmental and health risks of water treatment processes.