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In the present study the development of novel polymer-supported nanocomposite graphene oxide (GO)–TiO2 films, based on poly(L-lactic acid), one of the most exploited bioplastics worldwide, was explored for photocatalytic applications. The nanocomposites were synthesized and evaluated as photocatalysts for the removal of a mixture of nine antibiotics, consisting of two sulphonamides (sulfamethoxazole, sulfadiazine), three fluoroquinolones (levofloxacin, norfloxacin, moxifloxacin), one anti-TB agent (isoniazid), one nitroimidazole (metronidazole), one lincosamide (lincomycin) and one diaminopyrimidine (trimethoprim), which are commonly found in wastewaters. The films were synthesized using 1 wt% GO and different TiO2 content (10, 25, and 50 wt%) and characterized using Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Findings confirmed the successful immobilization of GO/TiO2 in all cases. The PLLA–GO–TiO2 50 wt% composite film demonstrated higher photocatalytic efficiency and, thus, was further investigated demonstrating excellent photostability and reusability even after four cycles. Overall, PLLA–GO–TiO2 50 wt% nanocomposite demonstrated high efficiency in the photocatalytic degradation of the antibiotics in various matrices including pure water and wastewater. [ABSTRACT FROM AUTHOR]

The application of TiO 2 nanoparticles as photocatalyst for the removal of pharmaceutical compounds from water is extensively applied as an alternative to the conventional treatment processes. However, application of TiO 2 as a powder requires energy costing separation stages to remove the catalyst at the end of the process. Thus, immobilization of the catalyst can be an attractive solution. Aiming to find a good support material for TiO 2 , in this study, the synthesis and characterization of three different PET/TiO 2 photocatalytic beads are described along with their application in the photocatalytic degradation of the anticonvulsant drug pregabalin (PGB). The PET/TiO 2 beads with different contents of TiO 2 filler (10 wt%, 20 wt% and 30 wt%) were synthesized by using an anti-solvent precipitation method and were characterized by different techniques, such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Among the different composites, PET/TiO 2 30 wt% beads proved to be the most efficient, achieving almost complete degradation of PGB within 6 h of treatment. The stability and reuse of the synthesized catalysts were also evaluated. Furthermore, the effect of matrix was examined, revealing slower kinetics in high loaded matrices like a leachate. Identification of the arising transformation products (TPs) was conducted using LC-HRMS analysis. Twenty-two TPs were identified, out of which fifteen were detected for the first time herein, stemming from hydroxylation, amidation, oxidation and oxidative deamination of PGB. Finally, the i n silico prediction of their toxicity was conducted based on ECOSAR software revealing mainly the formation of non-toxic compounds. However, amidation can cause the formation of toxic/harmful by-products but they are susceptible to photocatalysis thus being eliminated until the end of treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: Pesticides are listed among the main environmental stressors directly correlated with severe impacts on ecosystems and human health. Here, the potential of TiO2‐mediated photocatalytic oxidation of the insecticide thiacloprid, in aqueous media, is investigated thoroughly. Results: Degradation was investigated under various operational conditions, including the initial concentration of the pesticide, the type and amount of catalyst, pH and the presence of electron acceptors. The prevalence of TiO2 P25 in comparison to the other titania employed, is obvious both in the case of decomposition and carbon mineralization. Twenty‐seven transformation products generated during the photocatalytic decomposition of thiacloprid under UV‐A irradiation were elucidated by high‐resolution liquid chromatography mass spectrometry analysis, enabling the proposition of potential fragmentation pathways. The initial ecotoxicity of the insecticide determined by measurements of the bioluminescence of marine bacteria Vibrio fischeri was eliminated within 240 min of UV‐A irradiation in the presence of TiO2 P25. A phytotoxicity evaluation based on three eukaryotic plant species led to similar conclusions, resulting in the complete removal of phytotoxicity within 240 min of UV‐A illumination in the presence of TiO2 P25. Conclusions: These findings suggest that TiO2‐mediated photocatalytic oxidation has the potential to efficiently detoxify water containing neonicotinoid pesticides. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Cytarabine (CY) is an anticancer drug which has been identified in wastewater influents, effluents, and surface waters. In the present study, the degradation of CY under simulated solar light (SSL), by photo-Fenton (Fe3+/H2O2/SSL) and photo-Fenton-like processes (Fe3+/S2O82−/SSL and [Fe(C2O4)3]3−/H2O2/SSL), was investigated. The major parameters affecting the applied treatments (e.g., concentration of CY, Fe3+, H2O2, and S2O82−) were optimized and CY's complete removal was achieved within 45 min for all techniques used. Mineralization studies indicated that [Fe(C2O4)3]3−/H2O2/SSL treatment was the most efficient procedure since faster kinetics are achieved and higher mineralization percentage is reached compared to the other techniques used. Furthermore, 12 transformation products (TPs) were identified during the applied processes, by high resolution mass spectrometry, four of which were identified for the first time, indicating that CY molecule undergoes hydroxylation and subsequent oxidation, during the applied processes. Moreover, predictions of acute and chronic ecotoxicity of CY and its TPs on fish, daphnia, and green algae were conducted, using in silico quantitative structure activity relationship (QSAR) calculations. According to these predictions, the TPs generated during the studied treatments may pose a threat to aquatic environment. Finally, the efficiency of CY degradation by photo-Fenton and photo-Fenton-like treatment in real wastewater was evaluated, under the optimized conditions, which resulted in lower degradation rate constants compared to ultrapure water. [ABSTRACT FROM AUTHOR]

Photocatalytic oxidation of carboplatin, a platinum antineoplastic drug, has been investigated in aqueous heterogeneous solutions containing TiO 2 photocatalysts. The current study, besides the photocatalytic degradation of the drug, examines the utilization of the photo-reduction process occurring on the surface of the catalyst, leading simultaneously to the photo-deposition and recovery of platinum. TiO 2 photocatalytic process was evaluated for its ability to degrade the molecule of carboplatin and concurrently result in the synthesis of efficient platinum modified TiO 2 catalysts. The degradation kinetic was studied under different operational conditions, such as type of photocatalyst, catalyst loading, initial pH and addition of electron acceptors. Three systems were evaluated namely, TiO 2 P25 under UV-A and TiO 2 Kronos vlp 7000 under UV-A or visible illumination, with respect to their activity for substrate degradation and mineralization and their ability to bind platinum on their surface during photocatalytic oxidation of the drug. The initial degradation rate (r 0 ) decreased in the order TiO 2 P25/UV-A > TiO 2 Kronos vlp 7000/UV-A > TiO 2 Kronos vlp 7000/visible light. For TiO 2 P25/UV-A, the addition of 100 mg L −1  H 2 O 2 increases slightly the initial mineralization rate, while degradation rates gradually decrease as photocatalysis takes place in neutral and alkaline pH. Phytotoxicity measurements, showed that heterogeneous photocatalytic oxidation in the presence of TiO 2 P25 is capable of reducing the phytotoxicity of carboplatin. For TiO 2 P25 and TiO 2 Kronos vlp 7000 under UV-A illumination, photo-reduction and deposition of platinum is fully accomplished within 60 min of oxidation, while for TiO 2 Kronos vlp 7000 in the presence of visible light, the percentage of platinum deposited on the surface of the catalyst reaches 40%. Platinum photo-deposition is feasible, employing TiO 2 P25, even after the catalyst is reused. The synthesized platinum modified TiO 2 P25, demonstrated higher photocatalytic efficiency in comparison to the bare one, leading to 100% degradation of the model pollutant malachite green and 40% DOC reduction, after 30 min of photo-oxidation. [ABSTRACT FROM AUTHOR]

The presence of personal care product (PCP) residues in the aquatic environment is an emerging issue due to their uncontrolled release through graywater; for this reason, efforts are being made to develop methods to inactivate or eliminate this class of substances in the environment. In this work, homogeneous photocatalysis has been applied for the degradation of UV filter para-aminobenzoic acid (PABA), which exists in several types of PCPs, in order to identify the optimum degradation conditions. The oxidation of PABA by photo-Fenton and oxalate-induced photo-Fenton (ferrioxalate) processes was investigated, and the effect of various operating variables has been assessed, i.e., Fe (0.0035-0.014 g L), HO (0.025-0.2 g L), T (280-323 K), and type of radiation (UV-A, visible). Furthermore, experiments under optimal conditions have been performed in order to evaluate the transformation pathways and phytotoxicity of the treated PABA solution. [ABSTRACT FROM AUTHOR]

BACKGROUND Photocatalytic decomposition and mineralization of the herbicide clopyralid in aqueous solutions has been studied, aiming at an extended kinetic analysis, the elucidation of potential degradation pathways and the determination of ecotoxicity. RESULTS The pseudo-first-order degradation kinetics was studied under different operational conditions, such as type of photocatalyst, catalyst loading, initial pH and hydrogen peroxide (H2O2) concentration. The degradation rates proved to be strongly influenced by these parameters. Organic chlorine and nitrogen were easily converted into inorganic in the presence of TiO2 P25, resulting in 90% conversion in both cases within 180 min of illumination, while conversion was enhanced in the presence of H2O2. Ten possible transformation products were identified by means of LC-DAD-ESI/ MS analysis. Acute toxicity profiles using marine bacteria Vibrio fischeri showed an increasing trend during the first 60 min of illumination, which thereafter, progressively decreased. CONCLUSIONS Intermediates were formed mainly through pyridine ring transformation, dechlorination and decarboxylation reactions. The increasing trend in ecotoxicity at the first stages of degradation could be attributed to the progressive formation of intermediates more toxic than the parent molecule, or due to synergistic effects among the transformation products. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The metal–organic frameworks (MOF)-based photocatalytic treatment of lincomycin employing Basolite F300 as catalyst in the presence of two oxidants (H 2 O 2 , S 2 O 8 2-) was investigated. Both processes led to the elimination of lincomycin within 120 min of treatment. The oxidant's addition has an enhancing effect on the process, possibly from heterogeneous Fenton-type reactions. The concentration effect (0–300 mg/L) of the oxidants was explored, and the optimum amount achieving the highest degradation rate proved to be 100 mg/L for both oxidants. In total, 39 transformation products were identified out of which 24 are proposed for the first time, while the main transformation pathways were hydroxylation, S-oxidation, desulfurization, pyranose ring opening, and cleavage of the C-N bond. For an integrated evaluation of the process, toxicity measurements of the treated solution were performed by a bioassay using D.Magna. Toxicity was more pronounced in the first stages of treatment, implying synergistic effects between the formed intermediate transformation products (TPs), while notable toxicity reduction was achieved at the end of the process. Ecological structure-activity relationship (ECOSAR) predictions revealed the formation of many non-toxic TPs with hydroxylation being the key to the detoxification of the formed compounds. [Display omitted] • Complete degradation of lincomycin within 120 min of treatment. • Oxidant's addition plays a dominant role leading to Fenton-type reactions. • Thirty-nine transformation products are identified. • A notable toxicity reduction is achieved at the end of the process. • ECOSAR predictions reveal the formation of many non-toxic TPs. [ABSTRACT FROM AUTHOR]

The photocatalytic degradation of the organophosphorus insecticides fenitrothion and methyl parathion has been studied in aqueous titanium dioxide TiO 2 suspensions under simulated solar irradiation. The degradation kinetics followed a pseudo-first-order reaction and has been monitored by headspace solid-phase microextraction (HS-SPME) and gas chromatographic techniques (GC-FTD). Degradation of both insecticides has been a rapid process with half-lives varied between 3.7 and 12.9 min depending on the TiO 2 concentration as well as on the structure of the compound. The generated transformation by-products formed during the process were extracted by SPME used in two approaches: (a) by direct immersion in the filtered sample and (b) by exposing the fiber in the sample headspace. The intermediates were formed predominately via oxidation processes and were identified by gas chromatography and mass spectroscopy techniques. [ABSTRACT FROM AUTHOR]

The photocatalytic degradation of the organophosphorus insecticides fenthion and ethyl parathion has been studied in aqueous titanium dioxide suspensions under simulated solar irradiation. The degradation kinetics followed a pseudo-first order reaction and monitored by headspace solid-phase microextraction (SPME) and gas chromatography (GC) with flame thermionic detection. The degradation of both insecticides was a fast process with half-lives varying between 1.0 and 12.2 min depending on the TiO2 concentration as well as on the structure of the compound. The generated transformation products formed during the process were extracted by SPME: (a) by direct immersion of the fiber in the filtered sample and (b) by exposing the fiber in the headspace. The intermediates were formed predominately via oxidation processes and were identified by gas chromatography and mass spectrometry (MS). [Copyright &y& Elsevier]

In the present study the photocatalytic degradation of a mixture of eight antibiotics using Cu-modified TiO 2 photocatalysts has been explored. The catalysts have been synthesized following the Equilibrium Deposition Filtration (EDF) method and were characterized by different techniques such as X-ray Powder Diffraction (XRD), Transition electron microscopy (TEM), UV–vis Diffuse Reflectance Spectroscopy (DRS) etc. Their photocatalytic activity was investigated towards a mixture of antibiotics including isoniazid, metronidazole, sulfadiazine, sulfamethoxazole, trimethoprim, norfloxacin, moxifloxacin and lincomycin. Complete degradation was achieved within 30 min while various parameters were explored as the amount of modifier, the concentration of the catalyst, the effect of matrix and the participation of the reactive species. The most efficient catalyst (with 0.8 wt% Cu loading) was further tested against mineralization achieving a 75% reduction of total organic carbon within 6 h while almost complete detoxification on daphnia was achieved within the same time period. Moreover, photocatalytic treatment led also to complete elimination of the residual antimicrobial activity. Finally, the 0.8 wt% Cu-modified catalyst proved to be efficient on disinfection of a wastewater effluent against E. coli. [Display omitted] • Cu-doped catalysts with 0.1–4.9 wt% Cu loading were synthesized and characterized. • The catalysts were able to degrade a mixture of eight antibiotics. • Various parameters like the amount of dopant or the effect of matrix were explored. • Significant reduction of toxicity and residual antimicrobial activity was achieved. • Disinfection against E. coli was accomplished within 90 min of treatment. [ABSTRACT FROM AUTHOR]

In the present study, polymer supported nanocomposites, consisting of bio-based poly(ethylene furanoate) polyester and TiO2 nanoparticles, were prepared and evaluated as effective photocatalysts for anti-inflammatory/analgesic drug removal. Nanocomposites were prepared by the solvent evaporation method containing 5, 10, 15, and 20 wt% TiO2 and characterized using Fourier Transform Infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Thin films of them have been prepared by the melt press and optimization of the photocatalytic procedure was conducted for the most efficient synthesized photocatalyst. Finally, mineralization was evaluated by means of Total organic carbon (TOC) reduction and ion release, while the transformation products (TPs) generated during the photocatalytic procedure were identified by high-resolution mass spectrometry. [ABSTRACT FROM AUTHOR]

Recently the synthesis and application of bio-based composite materials, which contain polymeric and inorganic units such as TiO 2 , has gained much attention in the field of water/wastewater treatment, due to their better (and more practical) performance parameters. In the present study, recycled poly(ethylene terephthalate) (PET) has been used and evaluated as supporting polymer for Aeroxide P25 TiO 2 immobilization. PET-TiO 2 composite films were synthesized at different TiO 2 content (10%, 30% and 47% TiO 2) and characterized with different techniques such as X-ray Powder Diffraction (XRD), Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC), Scanning electron microscopy (SEM), etc. The photocatalytic activity of the new (synthesized) bio-based TiO 2 composite films was investigated under simulated solar irradiation for the degradation of a mixture of antibiotic pharmaceuticals (Isoniazid, Metronizadole, Sulfadiazine, Sulfamethoxazole, Trimethoprim, Norfloxacin, Moxifloxacin and Lincomycin). The immobilization of TiO 2 was successful in all cases and by increasing the photocatalyst concentration results in higher photocatalytic efficiencies. The new composite films were tested two times to assess their reusability, which found to be better for PET-10%-TiO 2 composite films; therefore the latter has been used for further investigation thus exhibiting good stability even after five cycles. The results showed that PET-10%-TiO 2 was efficient in degrading the antibiotic mixture in water and in wastewater matrix. • The photocatalytic activity of novel biobased-PET-TiO 2 composite films was tested. • XRD, TGA, DSC, SEM characterizations were performed. • At higher TiO 2 loading, reusability of the photocatalysts decreased. • PET-10% wt TiO 2 exhibited high performance even after 5 cycles. • Antibiotics degradation was achieved in water and wastewater matrix. [ABSTRACT FROM AUTHOR]

A green-oriented synthesis of highly photoactive nano-scaled graphitic carbon nitride (g-C 3 N 4) is presented with water to be utilized as a critical reagent in order to tune desired physicochemical properties, and so, to elevate the photocatalytic activity. The materials' optimization strategy involved the use of three precursors (melamine, urea or thiourea) and different thermal polycondensation (pyrolysis) durations. The synthesized materials were characterized by SEM, XRD, XPS, N 2 sorption, FT-IR, and UV–vis DRS. Their photocatalytic activity against a non-steroidal anti-inflammatory pharmaceutical compound, diclofenac, was evaluated under ultraviolent irradiation, also investigating the influence of pH, photocatalyst dosage/mass and concentration of H 2 O 2. The results revealed that the precursor, pyrolysis time and use of water effect significantly the physicochemical features and the photocatalytic activity. Urea-derived samples showed the highest specific surface areas and smallest crystalline domains, as well as the highest photocatalytic efficiency. The involved mechanisms were examined by exploring the optical properties, the role of the photo-generated radicals and the reactive oxygen species, as well as LC-MS analysis. The Orbitrap high-resolution mass-spectrometry analysis revealed the formation of 26 transformation products governed by different processes such as hydroxylation and further oxidation to keto derivatives and ring opening, decarboxylation/hydroxylation with further oxidation, dichlorination, and lactam formation. [Display omitted] • Water used as an "active" precursor for the synthesis of photoactive g-C 3 N 4. • Water during pyrolysis tune crucial physicochemical features of the photocatalyst. • The urea plus water derived material was found to be the most active against diclofenac. • The urea derived samples showed the highest specific surface area and the smallest crystalline size. [ABSTRACT FROM AUTHOR]

The photocatalytic activity of two bio-based polymer photocatalysts [poly(ethylene terephthalate)-TiO 2 (PET-TiO 2) and poly(L-lactic acid)-graphene oxide-TiO 2 (PLLA-GO-TiO 2)] towards Tamoxifen (TAM), Cyclophosphamide (CP), Cytarabine (CYT) and 5-Fluorouracil (5-FLU) removal was explored and compared. The highest photocatalytic activity for the degradation of the cytostatic drugs was accomplished by PET-TiO 2. Among the contaminants, TAM was the most easily removed, requiring 90 min for complete elimination, while CP showed the highest resistance to photocatalysis, not being completely removed after 6 h. Liquid chromatography coupled with high-resolution mass spectrometry analysis was employed for the identification of several transformation products (TPs) and potential pathways were proposed. A total of seventy (70) TPs including thirty-four (34) novel ones detected in AOPs were identified. The ecotoxicity of the mixture of the cytostatic drugs and TPs formed during the photocatalytic treatment was evaluated using Daphnia magna assay and was associated with the occurrence of specific TPs during the treatment process. The follow-up ECOSAR (Ecological Structure Activity Relationship) analysis further elucidated that only minor chemical transformations, such as the hydroxylation or the oxidative opening of an aromatic ring system, could hamper the adverse effects of cytostatic drugs in aquatic species. Such a comparative study on the mixture toxicity of cytostatics and their TPs is presented for the first time. Unlabelled Image • Effective photocatalytic degradation of a mixture of four cytostatic drugs • Increased efficiency of the nanocomposite PET/TiO 2 film compared to PLLA/GO/TiO 2 • Identification of 70 transformation products of cytostatics by Q-Orbitrap HRMS • Increased toxicity at the end of treatment via bioassay (D. magna) • In silico toxicity prediction of all transformation products by ECOSAR [ABSTRACT FROM AUTHOR]