Synthetic endocrine disruptors in the environment and water remediation by advanced oxidation processes

The performance of a visible light-responsive material Fe3O4/Bi2WO6 cooperating with peroxymonosulfate to degrade bisphenol A

In this study, the visible light-responsive catalysts Fe3O4/Bi2WO6 were prepared and characterized by BET, SEM, EDS, XRD, XPS, and MPMS. The performances of five catalysts (0.05 Fe/Bi, 0.13 Fe/Bi, 0.17 Fe/Bi, 0.21 Fe/Bi, and 0.30 Fe/Bi) for photocatalytic degradation of bisphenol A under visible light (300-W Xe lamp) were compared. Among five catalysts, 0.17 Fe/Bi (the molar ratio of Fe3O4 to Bi2WO6 was 0.17) acquired the highest BPA photocatalytic removal of 90.2% at 120 min. With the synergistic effect between Vis/0.17 Fe/Bi and peroxymonosulfate (PMS), the BPA removal obtained was as high as 100% at 90 min ([BPA] = 100 mg/L, [0.17 Fe/Bi] = 1.25 g/L, [PMS] = 2.0 g/L, and T = 25 °C). After five times reused of 0.17 Fe/Bi, its removal of BPA dropped by 13.4% in presence of PMS, which demonstrated 0.17 Fe/Bi possessed relatively stable performance. High BPA degradation was attributed to the attacking effects of various oxide species (SO4•-, •OH, h+, O2•-) generated in the Fe3O4/Bi2WO6/PMS system under the cooperation of photocatalyst Fe3O4/Bi2WO6 and oxidizing agent PMS.

Recent advances in nanomaterials based sustainable approaches for mitigation of emerging organic pollutants

Emerging organic pollutants (EOPs) are a category of pollutants that are relatively new to the environment and recently garnered a lot of attention. The majority of EOPs includes endocrine-disrupting chemicals (EDCs), antibiotic resistance genes (ARGs), pesticides, dyes and pharmaceutical and personal care products (PPCPs). Exposure to contaminated water has been linked to an increase in incidences of malnutrition, intrauterine growth retardation, respiratory illnesses, liver malfunctions, eye and skin diseases, and fatalities. Consequently, there is a critical need for wastewater remediation technologies which are effective, reliable, and economical. Conventional wastewater treatment methods have several shortcomings that can be addressed with the help of nanotechnology. Unique characteristics of nanomaterials (NMs) make them intriguing and efficient alternative in wastewater treatment strategies. This review emphasis on the occurrence of divers emerging organic pollutants (EOPs) in water and their effective elimination via different NMs based methods with in-depth mechanisms. Furthermore, it also delves the toxicity assessment of NMs and critical challenges, which are crucial steps for practical implementations.

Endocrine Disruptor Compounds in Environment: Focus on Women’s Reproductive Health and Endometriosis

Endometriosis is an estrogen-dependent gynecologic illness that has long-term effects on a woman’s fertility, physical health, and overall quality of life. Growing evidence suggests that endocrine-disrupting chemicals (EDCs) may be etiologically involved in the development and severity of the disease. We consider the available human evidence on EDCs and endometriosis, limiting ourselves to studies that have individually assessed chemical amounts in women. Dioxins, BPA, Phthalates, and other endocrine disruptors, like DDT, are among the evidence indicating an environmental etiology for endometriosis. Collectively, this review describes how environmental toxins are linked to lower fertility in women, as well as a number of reproductive diseases, focusing on the pathology of endometriosis and its treatments. Importantly, this review can be used to investigate techniques for preventing the negative effects of EDC exposure.

Cosmetic wastewater treatment technologies: a review

Over the past three decades, environmental concerns about the water pollution have been raised on societal and industrial levels. The presence of pollutants stemming from cosmetic products has been documented in wastewater streams outflowing from industrial as well as wastewater treatment plants. To this end, a series of consistent measures should be taken to prevent emerging contaminants of water resources. This need has driven the development of technologies, in an attempt to mitigate their impact on the environment. This work offers a thorough review of existing knowledge on cosmetic wastewater treatment approaches, including, coagulation, dissolved air flotation, adsorption, activated sludge, biodegradation, constructed wetlands, and advanced oxidation processes. Various studies have already documented the appearance of cosmetics in samples retrieved from wastewater treatment plants (WWTPs), which have definitely promoted our comprehension of the path of cosmetics within the treatment cycle; however, there are still multiple blanks to our knowledge. All treatments have, without exception, their own limitations, not only cost-wise, but also in terms of being feasible, effective, practical, reliable, and environmentally friendly.

Determination of hormones in urine by hollow fiber microporous membrane liquid-liquid extraction associated with 96-well plate system and HPLC-FLD detection

In this work, hollow-fiber microporous membrane liquid-liquid extraction (HF-MMLLE) was associated with a 96-well plate system for the determination of estrone, 17-β-estradiol, estriol and 17-α-ethinylestradiol in urine samples. This method exhibited some advantages, such as low cost, easy application, high-throughput and environmentally-friendly aspects. The type of organic solvent to fill the membrane, ionic strength effect, sample dilution, extraction and desorption time, and desorption solvent were examined. After the optimizations, the conditions were comprised of 45 min of extraction, 1-octanol as organic solvent and 15% (w/v) of NaCl; methanol was used as desorption solvent, and the desorption time was fixed at 10 min. The dilution of the sample increased the sensitivity due to the reduction of matrix effects; thus, urine samples were diluted 40-fold. The limits of detection ranged from 0.03 μg L^-1 for 17-β-estradiol to 15 μg L^-1 for estrone, and the limits of quantification ranged from 0.1 μg L^-1 for 17-β-estradiol to 10 μg L^-1 for estrone. The intra-day precision varied from 1.0% for estriol to 13.3% for 17-α-ethinylestradiol, and inter-day precision varied from 7.3% for estrone to 18.1% for estriol. The relative recoveries varied from 82 to 118%.

A critical review on diverse technologies for advanced wastewater treatment during SARS-CoV-2 pandemic: What do we know?

Advanced wastewater treatment technologies are effective methods and currently attract growing attention, especially in arid and semi-arid areas, for reusing water, reducing water pollution, and explicitly declining, inactivating, or removing SARS-CoV-2. Overall, removing organic matter and micropollutants prior to wastewater reuse is critical, considering that water reclamation can help provide a crop irrigation system and domestic purified water. Advanced wastewater treatment processes are highly recommended for contaminants such as monovalent ions from an abiotic source and SARS-CoV-2 from an abiotic source. This work introduces the fundamental knowledge of various methods in advanced water treatment, including membranes, filtration, Ultraviolet (UV) irradiation, ozonation, chlorination, advanced oxidation processes, activated carbon (AC), and algae. Following that, an analysis of each process for organic matter removal and mitigation or prevention of SARS-CoV-2 contamination is discussed. Next, a comprehensive overview of recent advances and breakthroughs is provided for each technology. Finally, the advantages and disadvantages of each method are discussed.

Recent Advancements in Cyclodextrin-Based Adsorbents for the Removal of Hazardous Pollutants from Waters

Water is an essential substance for the survival on Earth of all living organisms. However, population growth has disturbed the natural phenomenon of living, due to industrial growth to meet ever expanding demands, and, hence, an exponential increase in environmental pollution has been reported in the last few decades. Moreover, water pollution has drawn major attention for its adverse effects on human health and the ecosystem. Various techniques have been used to treat wastewater, including biofiltration, activated sludge, membrane filtration, active oxidation process and adsorption. Among the mentioned, the last method is becoming very popular. Moreover, among the sorbents, those based on cyclodextrin have gained worldwide attention due to their excellent properties. This review article overviewed recent contributions related to the synthesis of Cyclodextrin (CD)-based adsorbents to treat wastewater, and their applications, especially for the removal of heavy metals, dyes, and organic pollutants (pharmaceuticals and endocrine disruptor chemicals). Furthermore, new adsorption trends and trials related to CD-based materials are also discussed regarding their regenerative potential. Finally, this review could be an inspiration for new research and could also anticipate future directions and challenges associated with CD-based adsorbents.

Degradation of isoniazid by anodic oxidation and subcritical water oxidation methods: Application of Box-Behnken design

Pharmaceutical compounds released into the aquatic environment are known to cause toxic effects on the environment. Isoniazid is widely used in the treatment of tuberculosis and is, therefore, frequently encountered in environmental waters. In this study, the degradation of isoniazid was investigated by anodic oxidation and subcritical water oxidation method which are members of Advanced Oxidation Processes. The Box-Behnken Design was used to determine the effects of current, initial concentration, and electrolysis time on mineralization in the anodic oxidation process, which carried out a cell with a Pt cathode and boron-doped diamond anode. The highest mineralization value of 78.14% was achieved at optimal conditions of 300 mA, 3 h, and 100 mg/L initial concentration. The degradation of Isoniazid was also investigated under subcritical water conditions using an ecological oxidizing agent, H₂O₂. The maximum mineralization rate of 72.23% was obtained when 100 mM H₂O₂ was used for a 90 min treatment at 125 °C for 100 mg/L Isoniazid solution in the subcritical water oxidation process. The LC-MS results showed that the degradation products obtained by AO and SWO methods were different from each other. Finally, possible degradation mechanisms are proposed according to the degradation products obtained for both processes.

Hollow-structured amorphous prussian blue decorated on graphitic carbon nitride for photo-assisted activation of peroxymonosulfate

Heterogeneous activation of peroxymonosulfate (PMS) is one of the most promising techniques for wastewater treatment. Herein, an ingenious system by coupling of photocatalysis and PMS activation was developed, using hollow-structured amorphous prussian blue (A-PB) decorated on graphitic carbon nitride (g-C₃N₄) as the catalyst. Degradation of bisphenol A (BPA) via the A-PB-g-C₃N₄ mediated PMS activation under visible light (Vis) was systematically investigated. Astonishingly, it was found that ~ 82.0%, 92.6%, 98.2% and 99.3% of BPA (40 mg/L) were removed within 2, 4, 6 and 7 min, respectively, suggesting the extremely strong oxidizing capacity of the A-PB-g-C₃N₄/PMS/Vis system. Synergistic effect between the decorated A-PB and the g-C₃N₄ substrate promoted the Fe(III)/Fe(II) redox cycling and facilitated the charge transfer at the A-PB/g-C₃N₄ heterojunction interface. As a result, both photocatalysis and heterogeneous activation of PMS were boosted in the A-PB-g-C₃N₄/PMS/Vis system, leading to the production of large amount of reactive oxygen species (ROS). The various ROS (SO₄^•-, HO•, •O₂^- and ¹O₂) was responsible for the ultrafast degradation of BPA. Moreover, the A-PB-g-C₃N₄ catalyst also exhibited outstanding reusability and stability, retaining 98.9% of the removal percentage for BPA after five consecutive reaction cycles. This study suggests that the A-PB-g-C₃N₄ can be an all-rounder to bridge photocatalysis and PMS activation, and shed a new light on the application of multiple ROS for the ultrafast elimination of micropollutants from wastewater.

Synergism in TiO2 photocatalytic ozonation for the removal of dichloroacetic acid and thiacloprid

The synergistic effect of the photocatalytic ozonation process (PH-OZ) using the photocatalyst TiO₂ is usually attributed to influences of the physicochemical properties of the catalyst, pollutant type, pH, temperature, O₃ concentration, and other factors. It is also often claimed that good adsorption on the TiO₂ surface is beneficial for the occurrence of synergism. Herein, we tested these assumptions by using five different commercial TiO₂ photocatalysts (P25, PC500, PC100, PC10 and JRC-TiO-6) in three advanced oxidation systems - photocatalysis (O₂/TiO₂/UV), catalytic ozonation (O₃/TiO₂) and PH-OZ (O₃/TiO₂/UV) - for the degradation of two pollutants (dichloroacetic acid - DCAA and thiacloprid) simultaneously present in water. The synergistic effect in PH-OZ was much more pronounced in the case of thiacloprid, a molecule with low adsorption on the surface of the catalyst - in contrast to DCAA with stronger adsorption. The faster kinetics of catalytic ozonation (O₃/TiO₂) correlated with the higher exposed surface area of TiO₂ agglomerates, independent of the (lower) BET surfaces of the primary particles. Nevertheless, DCAA mineralization on the TiO₂ surface was much faster than thiacloprid degradation in solution. Therefore, we propose that a high BET surface area of the photocatalyst is crucial for fast surface reactions (DCAA mineralization), while good dispersion - the high exposed surface area of the (small) agglomerates - and charge separation play an important role in photocatalytic degradation or PH-OZ of less adsorbed organic pollutants (thiacloprid).

Removal of Pharmaceutical Residues from Water and Wastewater Using Dielectric Barrier Discharge Methods-A Review

Persistent pharmaceutical pollutants (PPPs) have been identified as potential endocrine disruptors that mimic growth hormones when consumed at nanogram per litre to microgram per litre concentrations. Their occurrence in potable water remains a great threat to human health. Different conventional technologies developed for their removal from wastewater have failed to achieve complete mineralisation. Advanced oxidation technologies such as dielectric barrier discharges (DBDs) based on free radical mechanisms have been identified to completely decompose PPPs. Due to the existence of pharmaceuticals as mixtures in wastewater and the recalcitrance of their degradation intermediate by-products, no single advanced oxidation technology has been able to eliminate pharmaceutical xenobiotics. This review paper provides an update on the sources, occurrence, and types of pharmaceuticals in wastewater by emphasising different DBD configurations previously and currently utilised for pharmaceuticals degradation under different experimental conditions. The performance of the DBD geometries was evaluated considering various factors including treatment time, initial concentration, half-life time, degradation efficiency and the energy yield (G50) required to degrade half of the pollutant concentration. The review showed that the efficacy of the DBD systems on the removal of pharmaceutical compounds depends not only on these parameters but also on the nature/type of the pollutant.

Pharmaceuticals and personal care products in water and wastewater: a review of treatment processes and use of photocatalyst immobilized on functionalized carbon in AOP degradation

The presence of emerging contaminants such as pharmaceutical and personal care products in many aqueous matrices have been reported. One of such matrix is streams of wastewater, including wastewater treatment plants inflows and outflows and wastewater flow by-passing wastewater treatment plants. Their persistence arises from their resistant to breakdown, hence they may remain in the environment over long time, with a potential to cause adverse effects including endocrine disruption, gene toxicity, the imposition of sex organs, antibiotic resistance and many others in some aquatic organisms exposed to arrays of residues of pharmaceutical and personal care products. Among the treatment techniques, advanced oxidation processes have been reported to be a better technique through which these PPCPs can be degraded in the WWTPs. Heterogeneous photocatalysis using various photocatalyst immobilized on solid support such as activated carbon, graphene and carbon nanotubes in AOPs have been shown to be a viable and efficient method of PPCPs degradation. This is because, the performance of most WWTPs is limited since they were not designed to degrade toxic and recalcitrant PPCPs. This review highlight the occurrence, concentration of PPCPs in wastewater and the removal efficiency of heterogeneous photocatalysis of TiO2 immobilized on solid supports.

Comparative endocrine disrupting compound removal from real wastewater by UV/Cl and UV/H2O2: Effect of pH, estrogenic activity, transformation products and toxicity

Extensive use of endocrine disruptor compounds (EDCs) and their release through various pathways into the environment are emerging environmental concerns. In this context, H₂O₂ and chlorine UV-based treatments were carried out to evaluate their efficiency in the removal of the bisphenol A (BPA), 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) at 100 μg L^-1 from ultrapure water and from wastewater treatment plants (WWTP). Photolysis was performed under different irradiation sources, i.e. UVC and UVA. The effect of H₂O₂ (3 and 30 mg·L^-1), free chlorine concentrations (1 and 2 mg·L^-1) and pH (5, 7 and 9) were also investigated. Toxicity (Raphidocelis subcapitata) and estrogenic activity (yeast estrogen screen - YES assay) were assessed during the processes. Compound removal at optimal operating parameters reached 100% after 15 and 2 min for UVC/H₂O₂ (pH 9 and 3 mg L^-1 of H₂O₂), and UVC/Cl (pH 9 and 2 mg L^-1 of chlorine), respectively. Total organic carbon (TOC) removal achieved 37% and 45% for the H₂O₂ and Cl-UV based process, respectively. The in vitro YES assay indicated that the formed by-products were non-estrogenic compounds, while the toxicity evaluation revealed high cell growth inhibition due to UVC/Cl byproducts. During the UV-based processes, 30 transformation products (TPs) were identified, in which three new chlorinated TPs from E2 and EE2 may be responsible for toxicity effects. EDC degradation by UV/Cl is faster than by UV/H₂O₂, although chlorinated toxic byproducts were also formed during the UV/Cl process.

Catalytic wet air oxidation of high BPA concentration over iron-based catalyst supported on orthophosphate

The catalytic performance of Fe supported on nickel phosphate (NiP) was evaluated for the removal of bisphenol A (BPA) by catalytic wet air oxidation (CWAO) at 140 °C and 25 bar of pure oxygen pressure. The prepared NiP and Fe/NiP materials were fully characterized by XRD, N₂-physisorption, H₂-TPR, TEM, and ICP analysis. Iron (Fe/NiP) impregnation of NiP support enhanced the BPA removal efficiency from 37.0 to 99.6% when CWAO was performed. This catalyst was highly stable given the operating conditions of acidic medium, high temperature, and high pressure. The Fe/NiP catalyst showed an outstanding catalytic activity for oxidation of BPA, achieving almost complete removal of BPA in 180 min at a concentration of 300 mg/L, using 4 g/L of Fe/NiP. No iron leaching was detected after the CWAO of BPA. The stability of Fe/NiP was performed over three consecutive cycles, noting that BPA conversion was not affected and iron leaching was negligible. Therefore, this catalyst (Fe/NiP) could be considered as an innocuous and effective long-lasting catalyst for the oxidation of harmful organic molecules.

Partition and Fate of Phthalate Acid Esters (PAEs) in a Full-Scale Horizontal Subsurface Flow Constructed Wetland Treating Polluted River Water

When used as highly produced chemicals and widely used plasticizers, Phthalate acid esters (PAEs) have potential risks to human life and the environment. In this study, to assess the distribution and fate of PAEs, specifically inside a full-scale horizontal subsurface flow constructed wetland, four PAEs including dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), and bis (2-ethylhexyl) phthalate (DEHP) were investigated. In effluent, PAEs concentration decreased 19.32% (DMP), 19.18% (DEP), 19.40% (DBP), and 48.56% (DEHP), respectively. Within the wetland, PAEs partitioned in water (0.18–1.12 μg/L, 35.38–64.92%), soil (0.44–5.08 μg/g, 1.02–31.33%), plant (0.68–48.6 μg/g, 0.85–36.54%), air and biological transformation (2.72–33.21%). The results indicated that soil and plant adsorption contributed to the majority of PAE removal, digesting DMP (19.32%), DEP (19.18%), DBP (19.40%), and DEHP (48.56%) in constructed wetlands. Moreover, the adsorption was affected by both octanol/water partition coefficient (Kow) and transpiration stream concentration factors (TSCF). This work, for the first time, revealed the partition and fate of PAEs in constructed wetlands to the best of our knowledge.

Bacitracin-assisted synthesis of spherical BiVO4 nanoparticles with C doping for remarkable photocatalytic performance under visible light

The spherical BiVO₄ nanoparticles with C doping were fabricated by using bacitracin as a biological template through hydrothermal-calcination method. And the prepared photocatalysts have excellent photocatalytic performance under visible light.

Adsorption mechanism and modelling of hydrocarbon contaminants onto rice straw activated carbons

The adsorption of Diphenolic acid (DPA), 2,4-Dichlorophenoxyacetic acid (2,4-D), and 2-methyl-4-chlorophenoxyacetic acid (MCPA) were examined in aqueous solution using activated carbon rice straw. The rice straw was activated by using two reagents, zinc chloride and phosphoric acid and named as RSZ, RSP, respectively. The results showed that both carbons have a relatively high adsorption capacity. Concerning the adsorption kinetic, the second-order model has better fit than the first model to experimental data. The adsorption yield of both carbons increased in the order: DPA < 2,4-D < MCPA. The pore volume diffusion model satisfactorily fitted the experiment on both carbons. Furthermore, solution pH has a high influence on the adsorption capacity for both carbons. The adsorption mechanism of selected pollutants onto carbon samples has been controlled by dispersion interaction π-π electrons and electrostatic interaction, moreover, the contribution of pore volume diffusion is the controlling mechanism of the overall rate of adsorption.

A review of the application of sonophotocatalytic process based on advanced oxidation process for degrading organic dye

Nowadays the use of conventional wastewater treatment methods is becoming increasingly challenging mainly due to the presence of organic matter in wastewater. Therefore, an emerging technology is needed to deal with these highly concentrated and toxic non-biodegradable organic matters. In the last few decades, advanced oxidation process (AOP) has emerged to treat wastewaters discharged from industries. Recently, researchers have shown interest to use the application of ultrasound (US) in photocatalysis, i.e. sonophotocatalysis, to improve the performance of the treatment process in the degradation of organic and inorganic contaminants in aqueous streams. Sonophotocatalysis is the combination of the use of ultraviolet (UV) and US.

Hydroxyl radical-mediated degradation of salicylic acid and methyl paraben: an experimental and computational approach to assess the reaction mechanisms

Advanced oxidation processes (AOPs) using various energy sources and oxidants to produce reactive oxygen species are widely used for the destruction of recalcitrant water contaminants. The current study is about the degradation of two emerging pollutants-salicylic acid (SA) and methyl paraben (MP)-by high-frequency ultrasonication followed by identification of the oxidation byproducts and modeling of the reaction mechanisms using the density functional theory (DFT). The study also encompasses prediction of the aquatic toxicity and potential risk of the identified byproducts to some aquatic organisms bussing the ECOSAR (Ecological Structure Activity Relationships) protocol. It was found that the degradation of both compounds was governed by •OH attack and the pathways consisted of a cascade of reactions. The rate determining steps were decarboxylation (~ 60 kcal mol^-1) and bond breakage reactions (~ 80 kcal mol^-1), which were triggered by the stability of the reaction byproducts and overcome by the applied reaction conditions. Estimated values of the acute toxicities showed that only few of the byproducts were harmful to aquatic organisms, implying the environmental friendliness of the experimental method.

Polyamide-Laccase Nanofiber Membrane for Degradation of Endocrine-Disrupting Bisphenol A, 17α-ethinylestradiol, and Triclosan

Contamination of potable water by endocrine disrupting chemicals (EDCs) is a growing problem worldwide. One of the possible treatments is the utilization of laccase enzyme catalyzing oxidation of phenolic structures of EDC when anchored in a polymeric nanofiber membrane. Previous studies failed to develop a membrane with a sufficiently active enzyme, or the immobilization process was too complicated and time-consuming. Here, we established an elegant method for immobilizing Trametes versicolor laccase onto polyamide 6 nanofibers (PA6-laccase) via adsorption and glutaraldehyde crosslinking, promoting high enzyme activity and easier applicability in water treatment technology. This simple and inexpensive immobilization ensures both repeated use, with over 88% of initial activity retained after five ABTS catalytic cycles, and enhanced storage stability. PA6-laccase was highly effective in degrading a 50-µM EDC mixture, with only 7% of bisphenol A, 2% of 17α-ethinylestradiol, and 30% of triclosan remaining after a 24-h catalytic process. The PA6-laccase membrane can lead to the improvement of novel technologies for controlling of EDC contamination in potable water.

Application of pea-like yolk–shell structured Fe3O4@TiO2 nanosheets for photocatalytic and photo-Fenton oxidation of bisphenol-A

Uniform pea-like yolk–shell (PLYS) structured magnetic TiO₂(PLYS-Fe₃O₄@TiO₂) nanosheets have been prepared via a combined kinetics-controlled mechanical force-driven and hydrothermal etching assisted crystallization method and characterized.

Photocatalytic oxidation of six endocrine disruptor chemicals in wastewater using ZnO at pilot plant scale under natural sunlight

Endocrine disruptors (EDs) are xenobiotics that interfere with the synthesis, secretion, transport, binding, action, and elimination of the natural hormones. In this paper, the photodegradation of six EDs in municipal wastewater treatment plant effluents at pilot plant scale is reported. The EDs were bisphenol A, bisphenol B, diamyl phthalate, butyl benzylphthalate, methyl p-hydroxybenzoate, and ethyl 4-hydroxybenzoate. ZnO as photocatalyst in tandem with Na₂S₂O₈ as electron acceptor under natural sunlight were used. The process was previously optimized under laboratory conditions through a photoreactor under artificial UVA irradiation studying the role of some key operating parameters (catalyst loading, effect of electron acceptor, and pH). Results carried out at pilot plant scale show that addition of ZnO in tandem with Na₂S₂O₈ strongly enhances degradation rates compared with photolytic test. At the end of the irradiation time (240 min), the remaining amounts of EDs ranged from 24% (butyl benzylphthalate) to 0% (< LOQ bisphenol B). The degradation rates were in the order: bisphenols > parabens > phthalates. After the photoperiod, 83% of the initial dissolved organic carbon was removed and toxicity decreased to acceptable values (11% inhibition to Vibrio fisheri). The photodegradation process was found to follow pseudo-first-order kinetic model with DT₅₀ ranging from 5 min (bisphenol B) to 102 min (butyl benzylphthalate). Thereby, photocatalytic oxidation using ZnO is an area of environmental interest for the treatment of polluted water, particularly relevant for Mediterranean countries, where solar irradiation is highly available.

The solvent effects on dimethyl phthalate investigated by FTIR characterization, solvent parameter correlation and DFT computation

This study set out with the aim of investigating the solvent effects on dimethyl phthalate (DMP) using FTIR characterization, solvent parameter correlation and DFT calculation. DMP exposed to 17 organic solvents manifested varying shift in the carbonyl stretching vibration frequency (ν_CO). Non-alkanols induced Band I and alkanols produced Band I and Band II. Through correlating the ν_CO with the empirical solvent scales including acceptor parameter (AN), Schleyer's linear free energy parameter (G), and linear free salvation energy relationships (LSER), Band I was mainly ascribed to non-specific effects from either non-alkanols or alkanol polymers ((alkanol)_n). ν_CO of the latter indicated minor red shift and less variability compared to the former. An assumption was made and validated about the sequestering of hydroxyl group by the bulky hydrophobic chain in (alkanol)_n, creating what we refer to as "screening effects". Ab initio calculation, on the other hand, provided insights for possible hydrogen binding between DMP and (ethanol)_n or between ethanol monomers. The two components of Band I observed in inert solvents were assigned to the two CO groups adopting differentiated conformations. This in turn prompted our consideration that hydrogen binding was highly selective in favor of lowly associated (alkanol)_n and the particular CO group having relatively less steric hindrance and stronger electron-donating capacity. Band II was therefore believed to derive from hydrogen-bond interactions mainly in manner of 1:1 and 1:2 DMP-(alkanol)_n complexes.

Functionalized magnetic nanoparticles: Synthesis, characterization, catalytic application and assessment of toxicity

Cost-effective water cleaning approaches using improved treatment technologies, for instance based on catalytic processes with high activity catalysts, are urgently needed. The aim of our study was to synthesize efficient Fenton-like photo-catalysts for rapid degradation of persistent organic micropollutants in aqueous medium. Iron-based nanomaterials were chemically synthesized through simple procedures by immobilization of either iron(II) oxalate (FeO) or iron(III) citrate (FeC) on magnetite (M) nanoparticles stabilized with polyethylene glycol (PEG). Various investigation techniques were performed in order to characterize the freshly prepared catalysts. By applying advanced oxidation processes, the effect of catalyst dosage, hydrogen peroxide concentration and UV-A light exposure were examined for Bisphenol A (BPA) conversion, at laboratory scale, in mild conditions. The obtained results revealed that BPA degradation was rapidly enhanced in the presence of low-concentration H₂O₂, as well as under UV-A light, and is highly dependent on the surface characteristics of the catalyst. Complete photo-degradation of BPA was achieved over the M/PEG/FeO catalyst in less than 15 minutes. Based on the catalytic performance, a hierarchy of the tested catalysts was established: M/PEG/FeO > M/PEG/FeC > M/PEG. The results of cytotoxicity assay using MCF-7 cells indicated that the aqueous samples after treatment are less cytotoxic.

Ultrasound-assisted advanced oxidation processes for water decontamination

The study reflects a part of my experience in sonochemistry and ultrasound-assisted advanced oxidation processes (AOPs) acquired during the last fifteen years with my research team. The data discussed were selected from studies with azo dyes, endocrine disrupting compounds and analgesic/anti-inflammatory pharmaceuticals, which are all classified as "hazardous" or "emerging" contaminants. The research focused on their treatability by ultrasound (US) and AOPs with emphasis on the mineralization of organic carbon. Some of the highlights as pointed out in the manuscript are: i) ultrasound is capable of partially or completely oxidizing the above contaminant groups if the operating conditions are properly selected and optimized, but incapable of mineralizing them; ii) the mechanism of degradation in homogeneous solutions is OH-mediated oxidation in the bulk solution or at the bubble-liquid interface, depending on the molecular properties of the contaminant, the applied frequency and pH; iii) US-assisted AOPs such as ozonation, UV/peroxide, Fenton and UV/Fenton are substantially more effective than ultrasound alone, particularly for the mineralization process; iv) catalytic processes involving TiO₂, alumina and zero-valent iron and assisted by ultrasound are promising options not only for the destruction of the parent compounds, but also for the mineralization of their oxidation byproducts. The degradation reactions in heterogeneous solutions take place mostly at the catalyst surface despite the high-water solubility of the compounds; v) sonolytic modification of the above catalysts to reduce their particle size (to nano-levels) or to decorate the surface with metallic nanoparticles increases the catalytic activity under sonolysis, photolysis and both, and improves the stability of the catalyst.

Biotransformation and reduction of estrogenicity of bisphenol A by the biphenyl-degrading Cupriavidus basilensis

The biphenyl-degrading Gram-negative bacterium Cupriavidus basilensis (formerly Ralstonia sp.) SBUG 290 uses various aromatic compounds as carbon and energy sources and has a high capacity to transform bisphenol A (BPA), which is a hormonally active substance structurally related to biphenyl. Biphenyl-grown cells initially hydroxylated BPA and converted it to four additional products by using three different transformation pathways: (a) formation of multiple hydroxylated BPA, (b) ring fission, and (c) transamination followed by acetylation or dimerization. Products of the ring fission pathway were non-toxic and all five products exhibited a significantly reduced estrogenic activity compared to BPA. Cell cultivation with phenol and especially in nutrient broth (NB) resulted in a reduced biotransformation rate and lower product quantities, and NB-grown cells did not produce all five products in detectable amounts. Thus, the question arose whether enzymes of the biphenyl degradation pathway are involved in the transformation of BPA and was addressed by proteomic analyses.

Raw and biologically treated paper mill wastewater effluents and the recipient surface waters: Cytotoxic and genotoxic activity and the presence of endocrine disrupting compounds

Paper mill effluents are complex mixtures containing different toxic compounds including endocrine-disrupting (EDCs) and genotoxic compounds. In the present study non-concentrated raw and biologically treated wastewaters from two paper mill plants with different paper production technologies i) Paper mill A uses virgin fibres, and ii) Paper mill B uses recycled fibres for paper production and the corresponding receiving surface waters, were assessed for their cytotoxic/genotoxic activity with SOS/umuC, Ames MPF 98/100 Aqua, and comet assay with human hepatoma HepG2 cells. In addition the levels of seven selected EDCs were quantified in wastewater samples and receiving surface waters. All investigated EDCs were confirmed in raw and biologically treated effluents from both paper mills with concentrations being markedly higher in Paper mill B effluents. In the receiving surface waters three of the studied EDCs were determined downstream of both paper mills effluent discharge. The wastewater samples and the recipient surface water samples from Paper mill A were not mutagenic for bacteria and did not induce DNA damage in HepG2 cells. On the contrary, half of the raw wastewater samples from Paper mill B were mutagenic whereas biologically treated wastewater and the recipient surface water samples were negative. In HepG2 cells most of the raw and biologically treated wastewater samples from Paper mill B as well as surface water samples collected downstream of Paper mill B effluent discharge induced DNA damage. The results confirmed that genotoxic contaminants were present only in wastewaters from Paper mill B that uses recycled fibres for paper production, and that the combined aerobic and anaerobic wastewater treatment procedure efficiently reduced contaminants that are bacterial mutagens, but not those that induce DNA damage in HepG2 cells. This study highlights that in addition to chemical analyses bioassays are needed for a comprehensive toxicological evaluation of complex wastewater samples.

Fate of Bisphenol A in Terrestrial and Aquatic Environments

Bisphenol A (2,2-bis[4-hydroxyphenyl]propane, BPA), the monomer used to produce polycarbonate plastic and epoxy resins, is weakly estrogenic and therefore of environmental and human health interest. Due to the high production volumes and disposal of products made from BPA, polycarbonate plastic and epoxy resins, BPA has entered terrestrial and aquatic environments. In the presence of oxygen, diverse taxa of bacteria, fungi, algae and even higher plants metabolize BPA, but anaerobic microbial degradation has not been documented. Recent reports demonstrated that abiotic processes mediate BPA transformation and mineralization in the absence of oxygen, indicating that BPA is susceptible to degradation under anoxic conditions. This review summarizes biological and nonbiological processes that lead to BPA transformation and degradation, and identifies research needs to advance predictive understanding of the longevity of BPA and its transformation products in environmental systems.

Removal of Endocrine Disruptors from Urban Wastewater by Advanced Oxidation Processes (AOPs): A Review

Over the last years the growing presence of endocrine disrupting compounds in the environment has been regarded as a serious sanitary issue. The more and more frequent detection of these compounds in the effluents of wastewater treatment plants poses the risk associated to their persistence into the aquatic systems as well as to their adverse effects on both public health and environment.

As conventional systems do not allow their efficient removal, great attention has been raised towards their possible treatment by Advanced Oxidation Processes (AOPs). They rely on the action of hydroxyl radicals, which are highly reactive species, able to oxidize recalcitrant and non-biodegradable pollutants.

AOPs can either provide contaminant partial degradation or their complete removal. As their effectiveness has been proved for a wide spectrum of both organic and inorganic pollutants, they are considered a suitable option for the treatment of contaminated aqueous media, especially when combined with conventional biological processes.

This paper aims at reviewing main AOPs for the removal of endocrine disruptors, in order to highlight the most important features of different technologies, thus providing their comparative assessment. To this end, a brief overview of the most frequently detected endocrine disruptor compounds was also discussed, in order to clarify their fate into the environment as well as the contamination pathways of greatest concern for human health.

Novel Bi₁₂O₁₅Cl₆ Photocatalyst for the Degradation of Bisphenol A under Visible-Light Irradiation

Bisphenol A (BPA), a typical endocrine-disrupting chemical, is widely present in water environments, and its efficient and cost-effective removal is greatly needed. Among various physicochemical methods for BPA degradation, visible-light-driven catalytic degradation of BPA is a promising approach because of its utilization of solar energy. Bismuth oxychloride (BiOCl) is recognized as an efficient photocatalyst, but its band gap, >3.0 eV, makes it inefficient for solar energy utilization, especially for degrading nondye pollutants like BPA. Thus, preparation and application of bismuth oxychloride photocatalysts with an increased visible-light activity are essential. In this work, inspired by density functional theory calculations, a novel bismuth oxychloride photocatalyst, Bi12O15Cl6, was designed. The nanosheets were successfully synthesized using a facile solvothermal method followed by a thermal treatment route. The prepared Bi12O15Cl6 nanosheets had a favorable energy band structure and thus exhibited a superior visible-light photocatalytic activity for degrading BPA. The BPA degradation rate by the Bi12O15Cl6 was determined to be 13.6 and 8.7 times faster than those for BiOCl and TiO2 (P25), respectively. The photogenerated reactive species and degradation intermediates were identified, and the photocatalytic mechanism was elucidated. Furthermore, the as-synthesized Bi12O15Cl6 nanosheets remained stable in the photocatalytic process and could be used repeatedly, demonstrating their promising application in the degradation of diverse pollutants in water and wastewater.

Removal of atrazine in water by combination of activated carbon and dielectric barrier discharge

Efficiency of modern wastewater treatment plants to remove or decompose persistent contaminants in low concentration is often insufficient to meet the demands imposed by governmental laws. Novel, efficient and cheap methods are required to address this global issue. We developed a new type of plasma reactor, in which atrazine decomposition by atmospheric dielectric barrier discharge (DBD) in dry air is combined with micropollutant adsorption on activated carbon textile and with extra bubbling of generated ozone. Investigation of reaction kinetics and by-product analysis shows that increasing input power with a factor 3.5 leads to deeper atrazine oxidation without significantly changing energy yield of atrazine removal. By-products of first and later generations are detected with HPLC-MS analysis in water and adsorbed on the activated carbon textile. Our reactor is compared in energy efficiency with reactors described in literature, showing that combination of plasma discharge with pollutant adsorption and ozone recycling is attractive for future applications of water treatment.

Degradation of organic pollutants and microorganisms from wastewater using different dielectric barrier discharge configurations--a critical review

The growing global drinking water crisis requires the development of novel advanced, sustainable, and cost-effective water treatment technologies to supplement the existing conventional methods. One such technology is advanced oxidation based on dielectric barrier discharge (DBD). DBD such as single and double planar and single and double cylindrical dielectric barrier configurations have been utilized for efficient degradation of recalcitrant organic pollutants. The overall performance of the different DBD system varies and depends on several factors. Therefore, this review was compiled to give an overview of different DBD configurations vis-a-viz their applications and the in situ mechanism of generation of free reactive species for water and wastewater treatment. Our survey of the literature indicated that application of double cylindrical dielectric barrier configuration represents an ideal and viable route for achieving greater water and wastewater purification efficiency.

Photonic efficiency of the photodegradation of paracetamol in water by the photo-Fenton process

An experimental study of the homogeneous Fenton and photo-Fenton degradation of 4-amidophenol (paracetamol, PCT) is presented. For all the operation conditions evaluated, PCT degradation is efficiently attained by both Fenton and photo-Fenton processes. Also, photonic efficiencies of PCT degradation and mineralization are determined under different experimental conditions, characterizing the influence of hydrogen peroxide (H2O2) and Fe(II) on both contaminant degradation and sample mineralization. The maximum photonic degradation efficiencies for 5 and 10 mg L(-1) Fe(II) were 3.9 (H2O2 = 189 mg L(-1)) and 5 (H2O2 = 378 mg L(-1)), respectively. For higher concentrations of oxidant, H2O2 acts as a "scavenger" radical, competing in pollutant degradation and reducing the reaction rate. Moreover, in order to quantify the consumption of the oxidizing agent, the specific consumption of the hydrogen peroxide was also evaluated. For all operating conditions of both hydrogen peroxide and Fe(II) concentration, the consumption values obtained for Fenton process were always higher than the corresponding values observed for photo-Fenton. This implies a less efficient use of the oxidizing agent for dark conditions.

Nonylphenols degradation in the UV, UV/H₂O₂, O₃and UV/O₃processes - comparison of the methods and kinetic study

This paper describes the results of experiments on the decomposition of selected nonylphenols (NPs) in aqueous solutions using the UV, UV/H₂O₂, O₃and UV/O₃processes. The goal of the research was to determine the kinetic parameters of the above-mentioned processes, and to estimate their effectiveness. These substances were selected because of their ubiquitous occurrence in the aquatic environment, resistance to biodegradation and environmental significance. As a result of the experiments, the quantum yields of the 4-n-nonylphenol (4NP) and NP (technical mixture) photodegradation in aqueous solution were calculated to be 0.15 and 0.17, respectively. The values of the second-order rate constants of the investigated compounds with hydroxyl radical and NP with ozone were also determined. The estimated second-order rate constants of 4NP and NP with hydroxyl radicals were equal to 7.6 × 10⁸-1.3 × 10⁹ mol⁻¹ L s⁻¹. For NP, the determined rate constant with ozone was equal to 2.01 × 10⁶ mol⁻¹ L s⁻¹. The performed experiments showed that NP was slightly more susceptible to degradation by the UV radiation and hydroxyl radicals than 4NP. The study demonstrated also that the polychromatic UV-light alone and also in combination with selected oxidizers (i.e. hydrogen peroxide, ozone) may be successfully used for the removal of selected NPs from the aqueous medium.