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Photodegradation of Fluoxetine Applying Different Photolytic Reactors: Evaluation of the Process Efficiency and Mechanism
摘要： Photolytic degradation of fluoxetine (FLX), a medicine commonly known as Prozac?, was evaluated by using different photochemical processes. The ultraviolet/microwave (UV/MW) process showed higher efficiency in all the aspects evaluated in this study. The energy consumption was equivalent to 1.94 × 10-4 kW h mg-1 L (UV/MW), while in the UV process the value was 1.20 × 10-2 kW h mg-1 L. The degradation kinetics were applied to the FLX, with rate constant (k) = 0.15 ± 0.01 min-1 and linear correlation coefficient (R2) = 0.980 for UV, and k = 6.15 ± 0.08 min-1 and R2 = 0.998 for UV/MW. The FLX degradation of 99.16% (UV/MW 5 min) and 98.90% (UV 120 min) were observed, evidencing higher efficiency for the first process. The monitoring of transformation products (TPs) through chromatographic analysis enabled the identification of 9 TPs, proving that for the UV/MW process, the hydroxylated structures are verified in high quantity.
关键词： photolysis,fluoxetine,transformation products,photochemical reactor,kinetics
更新于2025-11-19 16:56:35
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Effect of UV wavelength on humic acid degradation and disinfection by-product formation during the UV/chlorine process
摘要： The efficiency of the ultraviolet (UV)/chlorine process strongly depends on UV wavelength because chlorine photolysis and its subsequent radical formation are highly wavelength-dependent. This study compared the degradation of humic acid (HA) during the UV/chlorine process by low pressure mercury lamp (LPUV, 254 nm) and ultraviolet light-emitting diode (UV-LED, 275 and 310 nm). The results indicated that HA degradation followed the pseudo-first-order kinetics, and the fluence-based degradation rate constants (kobs) were significantly affected by UV wavelength and solution pH. HA degradation decreased greatly with increasing solution pH during the UV/chlorine process at 254 nm, while the opposite trend was observed at 275 and 310 nm. In the meantime, kobs decreased in the order of 275 nm > 254 nm > 310 nm at pH > 7.0. The changes of chlorine molar absorption coefficients at different UV wavelengths resulted in the variation of chlorine photodecay rates (kobs, chlorine), and the synergistic effects of kobs, chlorine and chlorine quantum yields (Φchlorine) affected HA reduction. The formation of disinfection by-products (DBPs) during the UV/chlorine process was also evaluated. A significant suppression on DBP formation and DBP-associated calculated theoretical cytotoxicity were observed at 275 nm high UV fluence and alkaline pHs. These findings in this study demonstrate that UV wavelength at 275 nm is more suitable for HA degradation by the UV/chlorine advanced oxidation process in practical applications.
关键词： Disinfection by-products,Ultraviolet light-emitting diode (UV-LED),UV/chlorine,Humic acid,Toxicity,UV wavelength
更新于2025-11-19 16:46:39
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Degradation of tetracycline by medium pressure UV-activated peroxymonosulfate process: Influencing factors, degradation pathways, and toxicity evaluation
摘要： This study employed the medium pressure UV/peroxymonosulfate (MPUV/PMS), a new sulfate radical-based advanced oxidation process, to eliminate tetracycline (TTC) in water. At pH = 3.7, initial TTC concentration of 11.25 μM, PMS dosage of 0.2 mM and UV dose of 250 mJ cm-2, 82 % of TTC was degraded by MPUV/PMS. The second-order reaction rate constants of TTC with SO4?- and ?OH were found to be 1.4 × 1010 M-1 s-1 and 6.0 × 109 M-1 s-1, respectively. Radical quenching experiments indicated that ?OH played the major role in the degradation of TTC. Higher PMS dosage (0.1 mM~1.0 mM) and higher pH (3~11) could accelerate the TTC removal. Besides, the presence of Cl- (0.1 mM~5.0 mM) and CO32- (0.05 mM~0.5 mM) could also promote the reaction. Eight transformation products (TPs) were identified, and the potential degradation pathways mainly involved hydroxylation, demethylation and decarbonylation processes. The variation in the genotoxicity was investigated using the umu-test, and the results indicate that the genotoxicity of TTC after the MPUV/PMS treatment significantly increased during the initial stage. In addition, the ecotoxicity and mutagenicity of TTC and its TPs were predicted using quantitative structure-activity relationship (QSAR) analysis, and the results revealed that some TPs could have equivalent and even higher toxicity than TTC. MPUV/PMS showed better performance in TTC degradation in real waters than in Milli-Q water. MPUV/PMS is concluded to be an efficient method for removing TTC, but more attention should be paid to the changes of toxicity during this process.
关键词： Tetracycline,Toxicity,Hydroxyl radical,Sulfate radical,Transformation products
更新于2025-09-23 15:23:52
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Experimental studies and mathematical simulation of intermittent infrared and convective drying of sweet potato (Ipomoea batatas L.)
摘要： Intermittent infrared and convective drying (IIRCD) is a novel drying method that can enhance energy efficiency and quality of dried product. The mechanism of drying using this method is not yet fully understood. Mathematical models that describe the drying process of IIRCD for agricultural crops do not exist. In this study, a physics based mathematical model was developed to understand the mechanism of drying sweet potato using IIRCD. The model was based on shrinkage dependent diffusivity and evaporation phenomenon. COMSOL Multiphysics finite element software was employed for the model simulation. The simulation results of moisture and temperature distribution were validated by experimental drying data. The results fitted closely with experimental data. Drying of sweet potato using IIRCD was found to be more efficient in terms of final product quality compared to convective hot-air drying method.
关键词： quality of dried products,COMSOL,Physics-based model,modelling and simulation
更新于2025-09-23 15:23:52
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Effect of photochemical advanced oxidation processes on the formation potential of emerging disinfection by-products in groundwater from part of the Pannonian Basin
摘要： This study evaluates the effect of photochemical advanced oxidation processes (AOPs) (O3/UV, H2O2/UV and O3/H2O2/UV) on the formation potential (FP) of emerging disinfection by-products including nitrogenous by-products (N-DBPs) and haloketones (HKs) in groundwater from part of the Pannonian Basin (AP Vojvodina, Republic of Serbia). Among the N-DBPs, the haloacetonitrile (HAN) precursor contents were 9.83 ± 0.59 μg/L while precursors of halonitromethanes, particularly trichloronitromethane (TCNM) were not detected. Similarly, precursors of HKs as carbonaceous DBPs were also not detected in raw water. Ozonation alone and H2O2/UV process with a lower UV dose maximally decomposed HAN precursors (about 70%) while during O3 based AOPs, HANFP varied significantly. Application of UV photolysis and H2O2/UV processes with increasing UV dose doubled the HANFP. Ozone alone, O3/UV and H2O2/UV slightly increased HKs formation potential, particularly 1,1-Dichloro-2-propanone FP (0.93 ± 0.21 to 2.01 ± 0.37 μg/L). None of the investigated treatments influenced the formation of TCNM precursors. The effect of the applied treatments on bromide incorporation was the most evident for HANs.
关键词： emerging disinfection by-products,ozone,bromide incorporation,photochemical advanced oxidation processes
更新于2025-09-23 15:23:52
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Red Fluorescent Chlamydia trachomatis Applied to Live Cell Imaging and Screening for Antibacterial Agents
摘要： In this study, we describe the application of a transformed Chlamydia trachomatis strain constitutively expressing the red fluorescent protein mCherry, to allow real-time monitoring of the infection cycle and screening for agents that block replication of C. trachomatis. The red fluorescent C. trachomatis strain was detected autonomously without antibody staining and was equally susceptible to doxycycline as the wild type strain. A high-throughput screening assay was developed using the transformed strain and automated fluorescence microscopy. The assay was used in a pilot screen of a 349 compound library containing natural products from Australian flora and fauna. Compounds with anti-chlamydial activity were tested for dose response and toxicity to host cells and two non-toxic compounds had 50% effective concentration (EC50) values in the low micromolar range. Natural products are valuable sources for drug discovery and the identified Chlamydia growth inhibition may be starting points for future drug development. Live cell imaging was used to visualize growth of the red fluorescent C. trachomatis strain over time. The screening assay reduced workload and reagents compared to an assay requiring immunostaining and could further be used to monitor the development of Chlamydia inclusions and anti-chlamydial effect in real time.
关键词： mCherry,antibacterial,Chlamydia trachomatis,Australian natural products,high content screening,fluorescence-based screening,anti-chlamydial
更新于2025-09-23 15:23:52
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Removal of pharmaceutically active compounds (PhACs) from real membrane bioreactor (MBR) effluents by photocatalytic degradation using composite Ag2O /P-25 photocatalyst
摘要： Pharmaceutically active compounds (PhACs) are emerging pollutants causing serious challenges to wastewater treatment plants due to poor biodegradability. In this study, the enhanced removal of highly recalcitrant and commonly monitored PhACs, carbamazepine (CBZ) and diclofenac (DCF) by heterogeneous photocatalysis was investigated using 5% Ag2O /P-25 photocatalyst. The photocatalyst was characterized by scanning electron microscope (SEM-EDX), Brunauer-Emmett-Teller (BET), and UV-vis diffuse reflectance spectra (UV-DRS). The effects of catalyst dose, initial pollutants concentration, and mineralization during the photocatalytic degradation of PhACs were investigated. The matrix effect was assessed in deionized water (DW) and real membrane bioreactor effluent (RME). Optimal CBZ and DCF removals of 89.10 % and 93.5 %, respectively for 180 min of UV irradiation were achieved at catalyst dosage of 0.4 g L-1 in DW matrix. However, the optimal catalyst dosages for CBZ and DCF in RME matrix were increased by factor 2 and 1.5, respectively, to achieve the same degree of removal. Declining trends of removal rate were observed when initial concentrations of both the PhACs were increased under optimal catalyst dosages, and kinetics seem to fit the Langmuir-Hinshelwood model. Photo-induced holes and ?OH were the dominant oxidation species involved in the photocatalytic degradation of the PhACs. A plausible reusability of 5% Ag2O /P-25 photocatalyst was observed for both the PhACs. Moreover, various aromatic/aliphatic intermediates generated during the photodegradation CBZ were identified using fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometry, and a possible multi-step degradation pathway was proposed. Overall, the removal of PhACs using 5% Ag2O /P-25 photocatalyst showed promising results in real wastewater.
关键词： PhACs,transformation products,Ag2O/P-25 photocatalysts,matrix effect,photocatalytic degradation
更新于2025-09-23 15:23:52
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Photocatalytic toluene degradation over Bi-decorated TiO2: Promoted O2 supply to catalyst’s surface by metallic Bi
摘要： In the photocatalytic volatile organic compounds (VOCs) degradation, the accumulation of intermediate products on the surface of catalysts could cause a decrease in activity through retarding reactant (e.g. O2) supply to surface active sites. Herein, Bi decorated TiO2 photocatalysts (Bi/TiO2) for photocatalytic toluene degradation were prepared and systematically studied. It is found that metallic Bi modification improves the ability of photocatalysts to capture O2. As a result, the activities of the Bi/TiO2 photocatalysts are obviously higher than that of the TiO2 for photocatalytic toluene degradation, and the productions of photogenerated reactive oxygen species (O2? and H2O2) over the Bi/TiO2 photocatalysts are almost equal to that over the TiO2 despite the fact that the separation efficiency of photoinduced charge carriers is decreased after the addition of Bi. Adsorbed benzaldehyde is the main surface intermediate on the surface of the Bi/TiO2 photocatalysts, whereas plenty of more readily oxidized aliphatic carboxylate species was monitored on the surface of the TiO2, which can be attributed to insufficient O2 supply to the TiO2 surface. This further indicates the positive role of the promoted O2 supply by Bi in the photocatalytic toluene degradation. The present work offers a new window for addressing the catalyst deactivation in the photocatalytic VOCs degradation.
关键词： The uptake of O2,Intermediate products,Metallic Bi,Photocatalytic VOCs degradation
更新于2025-09-23 15:22:29
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Targeted nanoparticles for multimodal imaging of the receptor for advanced glycation end-products
摘要： The receptor for advanced glycation end-products (RAGE) is implicated in multiple disease states such as cancer, diabetes and neurodegenerative disorders, and RAGE inhibitors are being explored as potential new therapies in such cases. Despite the known role RAGE plays in these conditions, there remains an urgent need for a molecular imaging agent that can accurately quantify RAGE levels in vivo, aid in validation of RAGE as a biomarker and/or therapeutic target, and support development of new RAGE inhibitors. This editorial highlights a multimodal nanoparticle-based imaging agent targeted at RAGE that was recently developed by Konopka and colleagues (Theranostics 2018; 8(18):5012-5024. doi:10.7150/thno.24791).
关键词： receptor for advanced glycation end-products,positron emission tomography,multimodal imaging
更新于2025-09-23 15:22:29
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Performance of various commercial TiO <sub/>2</sub> in photocatalytic degradation of a mixture of indoor air pollutants: Effect of photocatalyst and operating parameters
摘要： Photocatalytic oxidation (PCO) air cleaners can be installed in air handling units to reduce occupants’ exposure to hazardous gases, boost indoor air quality, and concomitantly lower HVAC energy consumption by lowering the required ventilation rate. In this work, photocatalytic activity of four commercialized titanium dioxide photocatalysts (P25, PC500, UV100, and S5-300A) for treating a mixture of seven prevalent volatile organic compounds (VOCs) were assessed in a continuous flow reactor. The impacts of major experimental factors namely concentration (15-100 ppb), relative humidity level (0-60% at 23?C), and residence time (0.012-0.05 s) on the removal efficiency and by-products generation were examined. Photocatalysts were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption, Fourier transform infrared (FTIR), and scanning electron microscopy (SEM). UV100 possessed the highest values for total VOC removal efficiency, which could be attributed to its large surface area, high porosity, good crystallinity, and large population of surface hydroxyls. Regarding relative humidity, two dominant trends were found: i) increasing the humidity resulted in lower removal efficiencies, or ii) existence of an optimum humidity level in some cases. The treatment efficiency followed the order: alcohols > ketones > aromatics > alkanes. The main by-products in the gas phase were formaldehyde, acetaldehyde, acetone, and propionaldehyde.
关键词： titanium dioxide,volatile organic compounds,indoor air quality,photocatalytic oxidation,relative humidity,residence time,by-products
更新于2025-09-23 15:22:29