Aqueous Matrices Research Articles

Highly Efficient Activation of Peroxymonosulphate by Co and Cu Co-Doped Sawdust Biochar for Ultra-Fast Removal of Bisphenol A

The rapid, efficient, and thorough degradation of Bisphenol A (BPA) is challenging. In this study, we prepared an effective peroxymonosulphate (PMS) activation catalyst derived from sawdust containing calcium carbonate. The Co and Cu co-doped sawdust biochar (CoO/CuO@CBC) catalyst could activate PMS quickly, and the degradation rate of BPA reached 99.3% in 5 min, while the rate constant was approximately 30 times higher than in the CBC/PMS and CoCuOx/PMS systems. Moreover, the interaction between CoO, CuO, and CBC endows the CoO/CuO@CBC catalyst with excellent catalytic performance under different conditions, such as initial pH, temperature, water matrix, inorganic anions, and humic acid, which maintained fast PMS activation via the cyclic transformation of Cu and Co for BPA degradation. The results demonstrated that both the radical (•O2− and •SO4−) and non-radical (1O2) pathways participate in the degradation of BPA in the CoO/CuO@CBC/PMS system. The efficient and stable degradation over a wide range of pH, temperature, and aqueous matrices indicates the potential application of the CoO/CuO@CBC catalyst.

Real-time monitoring of aqueous total N-nitrosamines by UV photolysis and chemiluminescence.

N-nitrosamines such as N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPIP), and N-nitrosopyrrolidine (NPYR) have been established as potent carcinogens that can induce diverse types of cancer. Several studies have extensively investigated the accurate quantification of total N-nitrosamines (TONO) and the intricate nature of the matrix in which they are detected. The potential for the formation of N-nitrosamines in post-combustion CO2 capture (PCCC) and water treatment has raised concerns. This study outlines a unique method for the quantification of TONO in aqueous matrices using UV photolysis and the subsequent detection of NO by chemiluminescence. This method offers benefits such as operation in the continuous mode and handling of high sample flow rates to achieve a low limit of detection (LOD) and a low limit of quantification (LOQ). The observed LODs for the individual N-nitrosamines of NDMA, N-nitrosomorpholine (NMOR), N-nitrosodibutylamine (NDBA), and NPIP range between 0.06 and 0.2µM at a sample flow rate of 0.25mL/min, while the LOD range is reduced to between 0.02 and 0.06µM at 0.75mL/min. Linear responses for the NO produced from specific N-nitrosamines are observed between 0.5 and 10µM. The developed method is resistant to interfering chemicals (i.e., nitrite, amines, and carbonyls) and exhibits high specificity.

Efficient removal of perfluorooctanoic acid from aqueous matrices using cationic surfactant functionalized graphene oxide nanocomposite: RSM and ANN modeling, and adsorption behaviour

Perfluorooctanoic acid (PFOA), a persistent and recalcitrant emerging organic contaminant, has garnered worldwide attention due to its pervasiveness and strong bioaccumulation, emphasizing the urgent necessity for effective removal strategies. To address PFOA contamination in the global aquatic environment, this study prepared cetyltrimethylammonium bromide (CTAB)-functionalized graphene oxide (GO-C) nanocomposites. The functionality of GO-C is controlled by varying loading ratios of CTAB to achieve satisfactory performance. After preliminary experiments that confirmed the superior performance of GO-C0.5 in PFOA removal, the response surface methodology (RSM) revealed the effects of different process parameters, which followed the sequence: adsorbent dose > pH > time. The optimum PFOA removal of 98.5 % was achieved at adsorbent dose: 200 mg/L, pH: 3.5, and time: 50 min, at an experimental temperature of 298 K. Furthermore, a predictive model using an artificial neural network was developed for PFOA adsorption, which closely aligns with the experimental data (R2: 0.9999). The PFOA adsorption was most accurately represented by Freundlich isotherm (R2: 0.9747) and pseudo-second-order kinetics (R2: 0.9995), with a maximum experimental adsorption capacity of ~709.94 mg/g under RSM optimized conditions. The adsorption mechanism involves electrostatic and hydrophobic interactions and hydrogen bonding, as confirmed by the spectroscopic and zeta potential analyses. Lastly, the competitive adsorption and regeneration experiments underscore the potential of GO-C nanocomposite in removing PFOA. Overall, this study provides insights into the development and application of sustainable and promising adsorbent for the removal of PFOA in wastewater stream.

Guidance on aqueous matrices for evaluating novel precipitants and adsorbents for phosphorus removal and recovery

Phosphorus (P) removal from water and recovery into useable forms is a critical component of creating a sustainable P cycle, although mature technologies for P removal and recovery are still lacking. The goal of this paper was to advance the testing of novel materials for P removal and recovery from water by providing guidance on the development of more realistic aqueous matrices used during materials development. Literature reports of “new” materials to remove P from water are often difficult to compare in terms of performance because authors use a myriad of water chemistries containing P concentrations, pH, and competing ions. Moreover, many tests are conducted in simplified matrices that do not reflect conditions in real systems. To address this critical gap, the research herein developed a systematic approach of identifying aqueous matrices relevant to P recovery, including key components in the aqueous matrices having the greatest influence on the mechanisms of P removal with emphasis on phosphate precipitation and phosphate adsorption, and providing guidelines on relevant “recipes” for aqueous solutions for testing novel materials. Key components in the aqueous matrices included hydrogen ion (i.e., pH), multivalent metal cations, and dissolved organic matter due to their influence on phosphate precipitation and adsorption mechanisms. Recipes for buffer solution and synthetic groundwater, surface water, anaerobic digestate, and stored urine are discussed in the context of P removal and recovery processes. Wherein the adoption of standard matrices in other fields have permitted direct comparison of processes or materials, it is anticipated that adoption of relevant aqueous matrix recipes for P removal and recovery will improve the ability to directly compare novel materials and processes.

WS2-Assisted Electrochemical Activation of Peroxymonosulfate for Eliminating Organic Pollutant in Water

Advanced oxidation process based on heterogeneous activation of peroxymonosulfate (PMS) has received significant attention in wastewater remediation. Herein, a facile and effective electrochemical method was introduced in a tungsten sulfide (WS2)-activated PMS process for the removal of a typical azo dye Acid Orange 7 (AO7) in aqueous solution. It was found that the electrochemical activation could remarkably promote the removal of organic pollutants by coupling with WS2/PMS system. The elimination of AO7 in the electro-assisted WS2-activated PMS (E/WS2/PMS) system achieved 95.8% of AO7 removal in 30 min, with the optimal conditions of 1.0 g/L WS2, 1.0 mM PMS, current density of 1.0 mA/cm2 and initial pH of 6.5. Based on quenching experiments and EPR techniques, mechanistic studies confirmed that hydroxyl radical (•OH) and singlet oxygen (1O2) are the primary reactive oxygen species for the oxidation of pollutants. In addition, the influences of pH, WS2 dosage, PMS concentration, current density, common anions and humic acid on the AO7 removal are also investigated in detail. Furthermore, the system exhibited resistance to aqueous matrices, verifying the accepted applicability in real water (i.e., Yangtze River water and Shahu Lake water). In summary, this study demonstrates a green system for the effective removal of contaminants in water, holding significant implications for practical application.

New Materials for Thin-Film Solid-Phase Microextraction (TF-SPME) and Their Use for Isolation and Preconcentration of Selected Compounds from Aqueous, Biological and Food Matrices.

Determination of a broad spectrum of analytes, carried out with analytical instruments in samples with complex matrices, including environmental, biological, and food samples, involves the development of new and selective sorption phases used in microextraction techniques that allow their isolation from the matrix. SPME solid-phase microextraction is compatible with green analytical chemistry among the sample preparation techniques, as it reduces the use of toxic organic solvents to the minimum necessary. Over the past two decades, it has undergone impressive progress, resulting in the development of the thin-film solid-phase microextraction technique, TF-SPME (the thin-film solid-phase microextraction), which is characterized by a much larger surface area of the sorption phase compared to that of the SPME fiber. TF-SPME devices, in the form of a mostly rectangular metal or polymer substrate onto which a thin film of sorption phase is applied, are characterized, among others, by a higher sorption capacity. In comparison with microextraction carried out on SPME fiber, they enable faster microextraction of analytes. The active phase on which analyte sorption occurs can be applied to the substrate through techniques such as dip coating, spin coating, electrospinning, rod coating, and spray coating. The dynamic development of materials chemistry makes it possible to use increasingly advanced materials as selective sorption phases in the TF-SPME technique: polymers, conducting polymers, molecularly imprinted polymers, organometallic frameworks, carbon nanomaterials, aptamers, polymeric ionic liquids, and deep eutectic solvents. Therefore, TF-SPME has been successfully used to prepare analytical samples to determine a broad spectrum of analytes in sample matrices: environmental, biological, and food. The work will be a review of the above-mentioned issues.

Isolation of Methane from Ambient Water and Preparation for Source-Diagnostic Natural Abundance Radiocarbon Analysis.

A key challenge in climate change research is apportioning the greenhouse gas methane (CH4) between various natural and anthropogenic sources. Isotopic source fingerprinting of CH4 releases, particularly with radiocarbon analysis, is a promising approach. Here, we establish an analytical protocol for preparing CH4 from seawater and other aqueous matrices for high-precision natural abundance radiocarbon measurement. Methane is stripped from water in the optionally field-operated system (STRIPS), followed by shore-based purification and conversion to carbon dioxide (CO2) in the CH4 Isotope Preparation System (CHIPS) to allow Accelerator Mass Spectrometry analysis. The blank (±1σ) of the combined STRIPS and CHIPS is low (0.67 ± 0.12 μg C), allowing natural sample sizes down to 10 μg C-CH4 (i.e., 30 L samples of 40 nM CH4). The full-system yield is >90% for both CH4-spiked seawater and ambient samples from CH4 hotspots in the Baltic Sea and the Arctic Ocean. Furthermore, the radiocarbon isotope signal of CH4 remains constant through the multistage processing in the STRIPS and the CHIPS. The developed method thus allows for in-field sampling and sample size reduction followed by precise and CH4-specific radiocarbon analysis. This enables powerful source apportionment of CH4 emitted from aquatic systems from the tropics to the polar regions.

Highlighting the adsorption mechanism of a fluoroquinolone antibiotic from wastewater on carbon xerogel by experiments, characterization, modelling and DFT simulation.

The application of a synthesized carbon xerogel (RFX) for the adsorptive removal from water of ciprofloxacin (CPX), a widely used fluoroquinolones-group antibiotic for humans and animals, has been reported in this work. The carbon xerogel was characterized by N2 adsorption-desorption isotherms, FTIR, Raman spectroscopy, TPD studies, elemental analysis, determination of isoelectric point (pHIEP) and scanning electron microscopy (SEM). CPX adsorption experiments were conducted in batch mode, using results obtained with F400 commercial activated carbon for comparison purposes. CPX adsorption kinetics were well-described by the pseudo-second-order model for both adsorbents and by the Elovich model in the case of F400 activated carbon. Therefore, CPX equilibrium adsorption capacity values were of 457 and 72mgg-1 for RFX xerogel and F400 activated carbon, respectively. This significant difference can be attributed to the higher specific surface area and micropores volume values of F400 carbon; in this sense, this material led to a slower CPX kinetic adsorption. Also, the Dual-site Langmuir model best-described the experimental CPX adsorption isotherms in both cases. By the adsorption studies at different solution pH, it could be concluded that several mechanisms, e.g., hydrophobic and π-π interactions, and electrostatic forces highly influenced CPX adsorption capacity. Furthermore, adsorption tests using several environmentally relevant aqueous matrices have been accomplished. In this case, a competitive effect between the natural organic matter (NOM) and the target pollutant occurred in all the tested real matrices, decreasing CPX adsorption capacity, especially remarkable for F400 activated carbon. Finally, Density Functional Theory (DFT) has been used to elucidate the interactions between CPX and adsorbents, finding a high relevance of the π-π electron donor-acceptor interactions in which CPX acts as an acceptor.

Ferrate(Ⅵ) oxidative degradation of capecitabine in aquatic matrices: Degradation performance, mechanisms, and toxicity assessment

The growing utilization of anticancer drugs in recent years has resulted in their presence in surface water and sewage, which could have ecological consequences. In this work, ferrate (Fe(VI)) was utilized to oxidize capecitabine (CAP), a frequently used anticancer drug that has gained attention lately. The experiments have demonstrated that Fe(VI) was quite reactive with CAP at pH 7. The addition of humic acid (0.1–10 mg L−1) significantly inhibited the oxidation process. Then, four reaction pathways, mainly including hydroxyl substitution, direct oxidation and cleavage of CO and CN bond were proposed based on twelve products detected by high-resolution hybrid quadrupole time-of-flight mass spectrometer. These pathways were further validated by theoretical calculations. Experiments conducted in water matrices assessed the applicability of Fe(VI) technology. Toxicity assessments of CAP and its intermediates were performed using the TEST program, and predictions indicated that the intermediates were generally less toxic than CAP. Overall, this work revealed that Fe(VI) has great potential to solve the environmental pollution problems associated with capecitabine in water.

Effective periodate activation by the ball-milled bimetallic zero-valent iron/manganese oxides catalyst for sulfamethoxazole degradation

Developing a green and efficient catalyst for oxidant activation to tackle refractory organics pollution is challenging for water purification. In this study, we prepared a zero-valent iron-based bimetallic catalyst (ZVI/Mn3O4) for periodate (PI) activation using a simple and convenient ball-milling method. Electrochemical characterization and theoretical calculations confirm that the synergy between Fe and Mn enables the ZVI/Mn3O4 system to exhibit higher electron transfer efficiency compared to its individual components. Consequently, the ZVI/Mn3O4/PI system demonstrated enhanced PI activation and significantly improved removal of sulfamethoxazole (SMX), with reaction rates being 18.61 to 57.01 times higher than the comparison systems. The influence of various physicochemical parameters on SMX removal was investigated, confirming the wide tolerance ZVI/Mn3O4/PI system towards multiple aqueous matrices. Furthermore, the scalability of this system for industrial applications was validated through the preparation of larger batches of catalysts (4.21 g per batch) and testing in a custom-designed magnetic plate continuous-flow reactor. Quenching experiments and electron spin resonance tests confirmed that •O2– and 1O2 were the primary reactive species responsible for SMX degradation, with no toxic iodine byproducts detected, attributed to the carefully designed catalyst, which optimized the interaction between PI and the catalyst. Based on these findings, a potential catalytic mechanism and degradation pathway were proposed, highlighting ZVI's role as an electron pump to enhance Mn3O4's activation of PI. Additionally, toxicity assessments via prediction, zebrafish cultivation, wheat germination, and E. coli culture confirmed the excellent detoxification capability of ZVI/Mn3O4/PI system for SMX degradation. Overall, this work provides a new research paradigm for the convenient manufacture of ZVI-based catalysts and the development of advanced techniques for PI activation in water purification.

In-tube extraction dynamic headspace coupled to gas chromatography-mass spectrometry for the sensitive analysis of volatile compounds in aqueous samples

Aim: Volatile organic compounds (VOCs) are often human-made contaminants used and generated in the manufacturing of numerous products, presenting notable environmental and health hazards. Therefore, the development of sensitive and reliable analytical methods is crucial for their detection with accuracy, timeliness, and automation capabilities. The objective of this study is to demonstrate the suitability of the in-tube extraction dynamic headspace (ITEX-DHS) sampling method for the gas chromatographic/mass spectrometric (GC/MS) analysis of BTEX (benzene, toluene, ethylbenzene, and xylenes) compounds in aqueous matrices. It emphasizes the method’s metrological reliability and innovative approach to precisely determining VOCs in aqueous environments providing a tool to prevent contamination of the agrifood sector. Methods: Following the optimization of various experimental parameters, including salt incorporation and adjustments of both dry purging and desorption conditions. The method’s performance was evaluated for repeatability, reproducibility, and robustness. Results: Limit of detection (LOD) and limit of quantification (LOQ) were for all substances determined lower than 50 and 100 ng/L, respectively. Average relative standard deviations below 5% were achieved for all analytes, with recovery rates ranging between 93% and 101%. Subsequently, the method was applied for the determination of BTEX in one hundred groundwater samples. The findings revealed that the BTEX levels were below the LOD in 84.2% of samples. However, in the remaining samples, more than one compound was detected at concentrations higher than the LOQ. Conclusions: The ITEX method emerges as a highly favorable alternative to both solid phase microextraction (SPME) and purge and trap (P & T) methods for determining BTEX in aqueous samples, providing significant advantages. Its strengths lie in its increased robustness, extended trap lifespan, and enhanced sensitivity, underscoring its superior performance in VOC analysis. The total analytical method allows the sensitive and robust determination of VOC.

Impact of Benzodiazepine Delorazepam on Growth and Behaviour of Artemia salina Nauplii.

Benzodiazepines, a significant group of newly recognised water contaminants, are psychotropic medications prescribed for common anxiety symptoms and sleep disorders. They resist efficient degradation during sewage treatment and endure in aquatic environments. Their presence in aquatic matrices is increasing, particularly after the recent pandemic period, which has led many people to systematically use benzodiazepines to manage anxiety. In previous studies, an important interference of this class of drugs on both the larval and adult stages of some aquatic species has been demonstrated, with effects on behaviour and embryonic development. This study examined the influence of delorazepam, a diazepam metabolite, on Artemia salina development to gain insight into responses in naupliar larvae. Results demonstrated that treatments (1, 5, and 10 µg/L) increase the hatching percentage and induce a desynchronisation in growth. Mortality was only slightly increased (close to 10% at six days post-hatching), but lipid reserve consumption was modified, with the persistence of lipid globules at the advanced naupliar stages. Locomotory activity significantly decreased only at 10 µg/L treatment. No teratogenic effects were observed, though modest damages were noticed in the posterior trunk and eyes, two targets of environmental toxicity. The negative impact of delorazepam on Artemia salina adds to those already reported in other species of invertebrates and vertebrates, which are not yet considered targets of these drugs. This study underscores the need for further research and immediate attention to this class of contaminants and the importance of monitoring their presence during environmental risk assessments.

Catalytic hydrodehalogenation of iodinated contrast agents in drinking water: A kinetic study

The occurrence of iodinated contrast media (ICM) in water bodies represents a significant threat for public health due to their strong biochemical stability and recalcitrance to conventional water treatment systems. In this work, the feasibility of catalytic hydrodehalogenation (HDH) for the degradation of a representative group of ICMs (iohexol (IHX), iopromide (IPR), iopamidol (IPM) and diatrizoic acid (DIA)) is investigated. Complete degradation and deiodination of the isolated ICMs (1.6·10−2 mmol L−1) was achieved in less than 30 min in the presence of 0.25 g L−1 of different precious metal catalysts (Pd/Al2O3, Rh/Al2O3 and Pt/Al2O3) under ambient conditions, closing iodine balance by >95 %. Based on the identified reaction intermediates and final products, reaction mechanisms were accordingly proposed. A sequential reaction pathway was proposed for DIA removal, while reaction mechanisms encompassing both sequential and concerted reaction steps were proposed for the non-ionic ICMs (IHX, IPR, and IPM). Subsequent kinetic models, which successfully described experimental data, were developed from the elucidated reaction mechanisms, considering all species involved in the reaction. The versatility of the process was finally demonstrated in the treatment of real aqueous matrices (surface water and tap water) spiked with the ICMs mixture, except in the case of Pt/Al2O3 which suffered deactivation due to surface poisoning by halides. For this catalyst, kinetic constants ranged from 0.31 to 0.22 min−1 in deionized water, and from 0.04 to 0.08 min−1 in surface water as the reaction matrix. Among the tested catalysts, Pd/Al2O3 showed the highest activity and stability for the removal of ICMs.

An Interdisciplinary Assessment of the Impact of Emerging Contaminants on Groundwater from Wastewater Containing Disodium EDTA

In recent years, there has been a surge in interest concerning emerging contaminants, also known as contaminants of emerging concern (CECs), due to their presence in environmental matrices. Despite lacking regulation, these chemicals pose potential health and environmental safety risks. Disodium EDTA, a widely utilized chelating agent, has raised concerns regarding its environmental impact. The present work aimed to verify the presence of Disodium EDTA at the exit of eight wastewater treatment plants discharging into some losing streams flowing within a large alluvial aquifer. Conducted in the Province of Parma (Northern Italy), the research employs a multidisciplinary approach, incorporating geological, hydrogeological, chemical, and microbial community analyses. Following a territorial analysis to assess industries in the region, through the use of ATECO codes (a classification system for economic activities), the study investigated the concentration of Disodium EDTA in effluents from eight diverse wastewater treatment plants, noting that all discharges originate from an activated sludge treatment plant, released into surface water courses feeding the alluvial aquifer. Results revealed detectable levels of Disodium EDTA in all samples, indicating its persistence post-treatment. Concentrations ranged from 80 to 980 µg/L, highlighting the need for further research on its environmental fate and potential mitigation strategies. Additionally, the microbial communities naturally occurring in shallow groundwater were analyzed from a hydrogeological perspective. The widespread presence of a bacterial community predominantly composed of aerobic bacteria further confirmed that the studied aquifer is diffusely unconfined or semi-confined and/or diffusely fed by surface water sources. Furthermore, the presence of fecal bacteria served as a marker of diffuse leakage from sewage networks, which contain pre-treated wastewater. Although concentrations of Disodium EDTA above the instrumental quantification limit have not been found in groundwater to date, this research highlights the significant vulnerability of aquifers to Disodium EDTA. It reveals the critical link between surface waters, which receive treated wastewaters impacted by Disodium EDTA, and groundwater, emphasizing how this connection can expose aquifers to potential contamination. At this stage of the research, dilution of wastewaters in surface- and groundwater, as well as hydrodynamic dispersion within the alluvial aquifer, seem to be the main factors influencing the decrease in Disodium EDTA concentration in the subsurface below the actual quantification limit. Consequently, there is a pressing need to enhance methodologies to lower the instrumental quantification limit within aqueous matrices. In a broader context, urgent measures are needed to address the risk of diffuse transport of CECs contaminants like Disodium EDTA and safeguard the integrity of surface and groundwater resources, which are essential for sustaining ecosystems and human health.

Photo-Fenton-like activity of Fe/ZnO structure applied as a heterogeneous catalyst for the methylene blue dye removal in aqueous matrices

This work developed efficient heterogeneous catalysts for the methylene blue (MB) dye degradation under photo-Fenton-like conditions. The material was modified to incorporate Fe(III) into ZnO, creating Fe/ZnO strucuture, and applied as heterogeneous catalysts at various pH levels. SEM analysis revealed an agglomerated and plate-like morphology of the synthesized catalysts. The enhanced structure facilitated a removal efficiency of 96.2% for MB dye when employing the photo-Fenton-based process using 5.0% Fe/ZnO catalyst. The high removal efficiency is attributed to the synergy between ≡Fe(III) and ≡Zn(II), which promotes the generation of photoradical species through the Fenton effect. Real water matrices served as a source of MB dye contamination, exhibiting minimal interference and achieving ∼100 % of removal. Scavenger studies indicate that •OH and e⁻ are the primary contributors to the high MB dye degradation efficiency. Additionally, the by-products formed after photo-Fenton process exhibit minimal toxicity towards Lactuca sativa L. No Fe(II) ions were leached at the end of the process. Eight cycles of degradation did not cause significant spectral changes in the FTIR analysis, as well as in the XRD patterns, indicating the material efficient and stable structure.

Polymer tethering strategy modified ZIF67 derived cobalt-confined nanocage for norfloxacin degradation: Tailored reactive sites and beneficial local microenvironment

The refined state of reactive sites and their local microenvironment largely determined the reaction performance of catalyst. Herein, we constructed hollow cobalt-confined carbon nanocage (Co-NC@Co/C-x) with rich surface pyridinic N and more exposed tailored Co sites through cobalt-incorporated polymer tethering strategy modified ZIF67 and later thermal depolymerization. Such features facilitate rapid surface enrichment of contaminants, accelerated electron transfer and enhance the availability of unpaired electron oxygen of metallic cobalt, demonstrating exceptional efficiency in Norfloxacin degradation (NFX, 97.7 % within 20 min, kobs = 0.528 min−1) with a significantly lower activation energy of 6.39 KJ mol−1. Mechanistic investigations prove the promotive interplay of peroxymonosulfate with reactive sites and elucidate the dominant role of non-free radicals 1O2 for NFX degradation. The theoretical calculation showcases that unpaired-electron surface oxygen of metallic cobalt induces the impurity cleavage of the O-O bond, triggering the promotive generation of 1O2. Co-NC@Co/C-6 samples exhibit robust NFX degradation across different aqueous matrices, demonstrating cyclic stability and universal degradation performance against various pollutants, and flowing degradation experiments and immobilized recyclable monolith fiber-like bobbles experiments further underline the green recovery and practical potential in wastewater treatment.

Stability evaluation from hydrogen peroxide spiking studies

The ability to detect traces of hydrogen peroxide (H2O2) in water is an important prerequisite to ensure a safe and reliable use of H2O2 for isolator or cleanroom sanitization. While the residual airborne H2O2 concentration can be easily monitored, detection of trace H2O2 residues in aseptically filled drug products is challenging. In an industrial setting, samples must be pulled, handled, stored, and transported before analysis takes place. Therefore, knowledge about the analyte stability in the relevant matrix is crucial to ensure correct results.The objective of this study was to provide stability data for the analyte at low concentrations and in aqueous solutions. For this, H2O2 was spiked into four different aqueous matrices at two different concentrations and stored up to 60 days at four different storage temperatures. The tested matrices included water, buffer, and an exemplary excipient solution with and without additional protein.A developmental quantitative, fluorometric Amplex UltraRed assay was applied for analysis. The results show clearly, that of the four storage temperatures investigated, only -80 °C resulted in reasonably good recovery of the spiked H2O2 content within two weeks or even up to two months of storage.

Photocatalytic efficacy of pyrite in the degradation of antiretroviral drugs: Biomphalaria glabrata as a bioindicator of toxic and genotoxic effects

Population growth and the increase in the consumption of different pharmaceuticals combined with the insufficiency in the removal of these compounds by conventional treatments have contributed to the increase in the detection of these contaminants in aquatic matrices. Aiming to contribute in solving this problem, this promoted the degradation of a mixture of the drugs lamivudine and zidovudine in different matrices (aqueous solution and synthetic effluent) using the heterogeneous photo-Fenton process applying pyrite as a catalyst and artificial solar radiation. At the end of the treatment, degradations greater than 99 % were found for zidovudine in both matrices studied, while for lamivudine, 97 % and 94 % degradations were obtained for aqueous solution and synthetic effluent, in that order. In the investigation of toxic effects using Biomphalaria glabrata molluscs, embryotoxicity tests showed embryonic lethality in 100 % of individuals for all samples. Acute toxicity tests on adult molluscs resulted in mortality rates of 100 % (aqueous solution after treatment) and 50 % (synthetic effluent after treatment). Thus, to investigate cellular changes, genotoxicity analyses were carried out, and different degrees of DNA damage were observed, however, the highest level of damage to this organism was not observed. Therefore, B. glabrata demonstrated to be sensitive to toxic effects at the concentrations present in the matrices studied, providing evidence to predict the ecotoxicological potential of samples when released into aquatic ecosystems.

The impact of inorganic salts on the ultrasonic degradation of contaminants: A review

This comprehensive review explores the interplay between inorganic salts and ultrasound-assisted degradation of various contaminants. The addition of salt to aqueous matrices has been attributed to increasing contaminant degradation via the salting-out effect. However, research investigating the impact of salt on degradation has yielded inconsistent results. This review incorporated degradation information from 44 studies organizing data according to compound class and ionic strength to analyze the impact of inorganic salts on cavitation bubble dynamics, contaminant behavior, radical species generation, and contaminant degradation. Frequency and salt type were assessed for potential roles in contaminant degradation. The analysis showed that high intensity ultrasound was most beneficial to degradation in salt solutions. Unexpectedly, hydrophilic compounds showed marked enhancement with increasing ionic strength while many hydrophobic compounds did not benefit as greatly. Based on the collected data and analysis, enhanced degradation in the presence of salt appears to be primarily radical-mediated rather than due to the salting-out effect. Finally, the analysis provides guidance for designing sonolytic reactors for contaminant degradation.

Single-step template-free synthesis of fluoro-functionalized covalent organic frameworks with a tunable hollow structure for extraction of phthalate acid esters from human urine

Phthalate acid esters (PAEs) are recognized as endocrine disruptors, exhibit carcinogenic characteristics, and have the potential to impair fertility, thereby posing significant risks to both the environment and human health. Consequently, biomonitoring and exposure assessment of PAEs are of paramount importance. Presently, the majority of detection methods for PAEs are centered on aqueous matrices, and the development of techniques for the identification of PAEs in complex matrices remains an area of active research. This paper designed and synthesized a novel fluoro-functionalized hollow covalent organic framework (F-HCOF), characterized by a tunable hollow spherical structure and enriched with fluorine functional groups, through a one-step self-template approach, which effectively regulated the formation of the hollow structure. The synthesized F-HCOF with tunable hollow structures and abundant F functional groups provided efficient diffusion pathways and adsorption sites, facilitating robust and selective adsorption of the target PAEs. Using F-HCOF as a coating, a solid-phase microextraction method was developed to extract PAEs from complex matrices. The method exhibited limits of detection ranging from 0.0108 to 0.0581 ng L−1, with enrichment factors spanning from 2535.3 to 8985.3. The self-made F-HCOF fibers demonstrated the capability to effectively enrich PAEs under various interference conditions, further verifying their feasibility for practical sample analysis. This work provided a strategic approach for the synthesis of F-functionalized hollow COF adsorbents and explored the formation process of hollow spheres. It enables matrix interference-resistant analysis of PAEs, and offers a practical method for studying PAEs exposure and metabolism within the human body.