Degradation Of Diclofenac Research Articles

Novel, Simple and Low-Cost Preparation of Ba-Modified TiO2 Nanotubes for Diclofenac Degradation under UV/Vis Radiation.

A novel low-cost synthesis of barium-modified TiO2 nanotube (TNT) arrays was used to obtain an immobilized photocatalyst for degradation of diclofenac. TNT arrays were prepared by electrochemical anodization of titanium thin films deposited on fluorine-doped tin oxide (FTO) coated glass by magnetron sputtering, ensuring transparency and immobilization of the nanotubes. The Ba-modifications were obtained by annealing solutions of Ba(OH)2 spin coated on top of TNT. Three different concentrations of Ba(OH)2 were used (12.5 mM, 25 mM and 50 mM). The crystalline structure, morphology and presence of Ba were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy, respectively. Ba-modified TiO2 nanotubes (BTNT) were tested for photocatalytic degradation of diclofenac under UV/Vis radiation and it was proven that all of the Ba-modified samples showed an increase in photocatalytic activity with respect to the unmodified TNTs. The most efficient photocatalyst was the sample prepared with 25 mM Ba(OH)2 which showed 90% diclofenac degradation after 60 min. This result was in agreement with cyclic voltammetry measurements that showed the largest increase in photo-oxidation current densities for the same sample due to the increased generation of •OH radicals obtained by a more efficient photogenerated charge separation.

Electro/magnetic superposition effects on diclofenac degradation: Removal performance, kinetics, community structure and synergistic mechanism

Electric and magnetic fields characterized by high efficiency, low consumption and environment-friendly performance have recently generated interest as a possible measure to enhance the performance of the biological treatment process used to remove refractory organics. Few studies have been carried out to-date regarding the simultaneous application of electric and magnetic fields on biofilm process to degrade diclofenac. In this study, 3DEM-BAF was designed to evaluate the electrio-magnetic superposition effect on diclofenac removal performance, kinetics, community structure and synergistic mechanism. The results show that 3DEM-BAF could significantly increase the average removal rate of diclofenac by 65.30 %, 57.46 %, 9.48 % as compared with that of BAF, 3DM-BAF, 3DE-BAF, respectively. The diclofenac degradation kinetic constants and dehydrogenase activity of 3DEM-BAF were almost 6.72 and 2.53 times higher than those of BAF. Microorganisms of 3DEM-BAF in the Methylophilus and Methyloversatilis genera were distinctively enriched, which was attributed to the screening function of electric field and propagation effect of magnetic field. Moreover, three processes were found to contribute to diclofenac degradation, namely electro-magnetic-adsorption, electro-chemical oxidation and electro-magnetic-biodegradation. Thus, the simultaneous application of electric and magnetic fields on biofilm process was demonstrated to be a promising technique as well as a viable alternative in diclofenac degradation enhancement.

Study of diclofenac removal by the application of combined zero-valent iron and calcium peroxide nanoparticles in groundwater

Diclofenac (DCF) is one of the most frequently detected pharmaceuticals in groundwater, posing a great threat to the environment and human health due to its toxicity. To mitigate the DCF contamination, experiments on DCF degradation by the combined process of zero-valent iron nanoparticles (nZVI) and nano calcium peroxide (nCaO2) were performed. A batch experiment was conducted to examine the influence of the adding dosages of both nZVI and nCaO2 nanoparticles and pH value on the DCF removal. In the meantime, the continuous-flow experiment was done to explore the sustainability of the DCF degradation by jointly adding nZVI/nCaO2 nanoparticles in the reaction system. The results show that the nZVI/nCaO2 can effectively remove the DCF in the batch test with only 0.05 g/L nZVI and 0.2 g/L nCaO2 added, resulting in a removal rate of greater than 90% in a 2-hour reaction with an initial pH of 5. The degradation rate of DCF was positively correlated with the dosage of nCaO2, and negatively correlated with both nZVI dosage and the initial pH value. The order of significance of the three factors is identified as pH value > nZVI dosage > nCaO2 dosage. In the continuous-flow reaction system, the DCF removal rates remained above 75% within 150 minutes at the pH of 5, with the applied dosages of 0.5 g/L for nZVI and 1.0 g/L for nCaO2. These results provide a theoretical basis for the nZVI/nCaO2 application to remove DCF in groundwater.

Phosphate-induced activation of peracetic acid for diclofenac degradation: Kinetics, influence factors and mechanism

Activating peroxides to produce active substances is the key to advanced oxidation processes (AOPs), but this usually requires energy or is accompanied by additional contaminants. In this study, diclofenac (DCF) was effectively removed by peracetic acid (PAA) in phosphate buffer (PBS). According to the results of radical scavenging experiments and electron paramagnetic resonance (EPR), hydroxyl radical (•OH) and organic radicals (i.e., CH3C(=O)OO• and CH3C(=O)O•) generated from PBS-activated PAA might be the dominant reactive species responsible for DCF degradation. At neutral pH, PBS/PAA system exhibited the best degradation efficiency on DCF. Presence of NO3−, SO42− and Cl− had little effect on the removal of DCF, while HCO3− and natural organic matter (NOM) significantly inhibited DCF degradation in PBS/PAA system, resulting in the lower degradation efficiency of DCF in natural waters than that in ultrapure water. Finally, four possible degradation pathways, including hydroxylation, formylation, dehydrogenation and dechlorination, were proposed based on the detected reaction products. This study suggests that PBS used to control solution pH should be applied cautiously in PAA-based AOPs.

Optimal design of silver@silver sulfide-modified WS2 and its application in photocatalytic diclofenac degradation and H2 generation

WS2 nanoplates modified with either Ag2O (~10 nm, Ag2O/WS2) or Ag2S (around 25–35 nm; Ag2S/WS2) nano-architectures were constructed by a deposition followed by a hydrothermal approach, to form innovative p-n hetero-junction photocatalysts. The Ag2S/WS2 catalyst exhibited a marked photo-catalytic degradation (λ > 430 nm, 160 W) of diclofenac (DCF; 0.060 g/l) through H2O2 (1 ×10-4 M) under visible light illumination (K=43.6 ×10-3 min-1) exceeding that of Ag2O/WS2 (K=25 ×10-3 min-1). The enhanced performance of Ag2S/WS2 is attributed to anchoring Ag NPs and to the strong coupling of WS2 nano-plates with Ag2S composing higher surface area and pore volume values (26.172 m2/g, 0.073 cc/g). The detected active species during DCF degradation implicates that •O2⁻ was the major radical species. This work also studied the different influences of some dissolved inorganic ions, e.g., Cl–, PO43–, and HCO3−, on a simulated DCF degradation procedure. A remarkable photochemical activity towards H2 generation is accomplished on the heterostructure Ag2S/WS2 (1220μmolg−1) facilitated by very low amounts of Ago and surface roughness. It was deduced that the ratio of Ag nanoparticles manipulates both the degradation and water splitting reactions since it affects the accessible number of active sites.

Ozonation of diclofenac in a laboratory scale bubble column: Intermediates, mechanism, and mass transfer study

Diclofenac (DCF), a non-steroidal analgesic drug, has been recurrently detected in surface and groundwater during the past two decades. Traces of DCF pass through the conventional wastewater treatment facilities without any alteration due to its resistance and high stability. This study aims the complete degradation and partial mineralization of DCF by an ozonation process. The findings of the study suggest that increasing pH of the system and ozone supply rate, and generation of hydroxyl radicals in situ enhance the degradation process. In contrast, the increasing initial concentration of DCF slows down the process. The pseudo-first-order reaction rate constants were in the range of 0.0742 – –0.0979 min−1. A model has been developed to predict the behavior of the rate constant with various operating variables. High volumetric mass transfer coefficients (i.e., 1.150–2.717 × 103 s−1) was observed during the mass transfer study of ozone in water. A probable mechanism for ozonation is suggested along with the structures of major intermediates formed during the oxidation. Distinct orange pigments appeared during the reaction, which confirmed the production of DCF-2, 5-iminoquinone. Di-chloro aniline, 5-hydroxy DCF. The carboxylic acids were mainly detected as the metabolites. The treatment cost was estimated to be USD 0.80 for treating 1 m3 of the solution containing 50 mg dm−3 DCF. In addition, the effect of other water matrices on DCF degradation was also investigated and reported.

H2O2-assisted Sonophotocatalytic Degradation of Diclofenac using a Visible Light-Active Flower-like Micron-sized TiO2 Photocatalyst

The recovery of TiO2 nanoparticles after utilization is a major challenge that hinders the wide-scale implementation of photocatalytic technology in wastewater treatment. In this study, an easily recoverable flower-shaped micron-sized TiO2 (MST) photocatalyst was synthesized from nano-sized TiO2 seeds via a hydrothermal process. The synthesized MST photocatalyst displayed an average particle size of 1.577 μm with 2.7 eV bandgap energy and 100.18 m2/g surface area. The photocatalytic performance of the synthesized material was evaluated for the degradation of diclofenac (DCF) from aqueous solution under visible light. The degradation efficiency under visible light reached 52.87% in 120 min. When photocatalysis was coupled with ultrasonication (US), namely sonophotocatalysis, the DCF degradation efficiency increased to 62.61%. The highest DCF degradation efficiency (86.92%) was achieved under the optimized conditions of 30 kHz US frequency, 0.4 g/L of TiO2 loading, 10 ppm initial concentration of DCF, and 1.0 mM H2O2 dosage. The synergy index of sonophotocatalysis was 1.25, indicating the synergistic effects of both sonocatalysis and photocatalysis on DCF degradation efficiency. The MST photocatalyst was easily recovered through centrifugation after reaction and reused for another two cycles of sonophotocatalysis. The photocatalyst was significantly stable under these process conditions, with only a 5.19% decrease in degradation after three consecutive cycles.

UV/H2O2 degradation of diclofenac in a photocatalytic fuel cell

The purpose of this work was to construct an integrated reactor which could photoelectrocatalytically generate hydrogen peroxide under solar radiation and simultaneously degrade a recalcitrant pollutant by the UV/H2O2 process. Diclofenac has been chosen as water soluble model pollutant. Hydrogen peroxide has been produced by atmospheric oxygen reduction in a photocatalytic fuel cell. The cell comprised a transparent photoanode electrode bearing a combined CdS/TiO2 photocatalyst and a carbon cloth cathode bearing nanoparticulate carbon without any other electrocatalyst. Diclofenac was dissolved in the cathode compartment where hydrogen peroxide was generated and the pollutant was degraded by UV radiation support. Degradation was monitored by UV–Vis spectrophotometry and by high performance liquid chromatography. The results show that an integrated reactor functionality is realistic and effective and it provides an alternative route for sustainable operation aiming at environmental remediation.

Diclofenac degradation based on shape-controlled cuprous oxide nanoparticles prepared by using ionic liquid.

Persulfate oxidation technology is widely used in wastewater treatment, but there are still many disadvantages, such as high energy consumption, side reaction and narrow pH applicability. Copper oxides can activate persulfate steadily with higher efficiency. In this paper, a novel preparation method of shape-controlled cuprous oxide (Cu2O) nanoparticles featured with high catalytic performance was explored. It was found that adding ionic liquid 1-butyl-3-methylimidazolium bromide ([BMIM]Br) during preparation of Cu2O can improve the degradation rate of diclofenac (DCF). Cu2O nanoparticles possess good stability in consecutive cycling tests, which was confirmed by X-ray photoelectron spectroscopy. The possible mechanism of Cu2O activating persulfate at different initial pH conditions was discussed based on electron paramagnetic resonance spin-trapping experiment. It was found that DCF was efficiently degraded in the Cu2O/peroxydisulfate (PDS) system within a broad pH range from 5 to 11. It proved via a quenching experiment that the activation process of PDS mainly occurs on the surface layer of Cu2O nanoparticles. As a result, shape-controlled Cu2O nanoparticles prepared by ionic liquid are expected to be used for in situ chemical oxidation, which is an effective oxidation processes to degrade DCF remaining in surface water and ground water.

Insights of emerging contaminants removal in real water matrices by CWPO using a magnetic catalyst

The study was focused on the application of catalytic wet peroxide oxidation (CWPO) with a synthesized magnetic catalyst (Fe3O4/MWCNTs) for the treatment of real water matrices spiked with pharmaceutical compounds. CWPO was carried out by modifying the initial pH of surface water (SW), wastewater treatment plant (WWTP) effluent, brewery wastewater (BW) and hospital wastewater (HW), and the effect of the addition of the emerging pollutants naproxen (NAP) and diclofenac (DCF). From the experimental results, pH and concentration of NAP and DCF in CWPO were crucial factors in the successful pollutants removal from water matrices. The lab-prepared catalyst showed high removal rates of NAP and DCF from different water matrices spiked with the NAP-DCF mixture at pH 5.0. The highest average removal rate of TOC (75%), NAP (66%), DCF (76%), TN (39%) and aromaticity (68.39%) was obtained for SW matrix using 1.0 g L−1 of catalyst, pH ≈ 5.0, 5 mM of H2O2 and 60 °C. The mineralization decreased with the increase of the initial TOC concentration of the tested matrix. By CWPO tests of the real water matrices it was demonstrated that DCF removal was higher than NAP. From the recyclability tests, the catalyst demonstrated high activity and stability along three consecutive CWPO cycles of 8 h each one. The pseudo-second order model well-described the degradation of NAP and DCF. Finally, aromaticity and toxicity of the effluents were greatly reduced after CWPO treatment. This work demonstrated that CWPO with the magnetic catalyst is an efficient method to remove DCF-NAP mixtures from real aqueous matrices.

In situ growth and crystallization of TiO2 on polymeric membranes for the photocatalytic degradation of diclofenac and 17α-ethinylestradiol

TiO2in situ growth on three commercial membranes (polysulfone – PS, polyvinylidene fluoride – PVDF and polytetrafluoroethylene – PTFE) and its hydrothermal post-crystallization to transform TiO2 into a photocatalytically-active phase, were investigated under mild synthesis conditions to preserve the textural properties of the supports. The membranes were successfully prepared and characterized by scanning electron microscopy, thermogravimetry analysis, N2 physisorption, X-ray diffraction, and water contact angle measurements, among other techniques. Membrane supports with a more opened porosity and high hydrophilicity allowed to enhance the content and distribution of the anatase TiO2 nanoparticles on the membrane surface. The efficiency and the permeate flux of the developed membranes were investigated to simultaneously remove diclofenac (DCF) and 17α-ethinylestradiol (EE2) from water by adsorption and UV–LED (light-emitting diode) photocatalysis under continuous recirculating mode. All TiO2 membranes achieved removal efficiencies above 90% for both contaminants, EE2 being always preferentially adsorbed over DCF due to electrostatic repulsions between the DCF molecules and the surface of these membranes. The permeate flux of TiO2 membranes was enhanced after UV-LED exposure as a consequence of the degradation of the contaminants adsorbed on the membrane surface during the dark phase. Moreover, the stability of TiO2 nanoparticles on these membranes was studied by static tests under sonication and several consecutive reaction cycles. The TiO2 membrane prepared with PVDF was the most stable, also presenting a high photocatalytic activity.

Boron and phosphorus co-doped one-dimensional graphitic carbon nitride for enhanced visible-light-driven photodegradation of diclofenac

In this study, the boron (B) and phosphorous (P) co-doped one-dimensional graphitic carbon nitride (CN) (1D BPCN) photocatalysts with various P loadings have been synthesized by hydrothermal-assisted thermal polymerization method for rapid and efficient photodegradation of diclofenac (DCF) under visible light irradiation. The hydrolysis of melamine produces cyanuric acid during the hydrothermal treatment, and then the layered melamine-cyanuric acid complex serves as the supramolecular unit to form the 1D hexagonal-shaped BPCN after thermal polymerization at 500 °C for 4 h. The B and P heteroatoms can be doped inside the CN framework to form P-N and B-C bonds, resulting in the decrease in electric resistance to accelerate the electron transfer as well as the reduction of hole-electron recombination rate to enhance the photocatalytic activity of BPCN. Addition of 3 mL of phosphoric acid significantly enhances the visible-light-responsive photocatalytic activity of 1D BPCN toward DCF degradation. The photodegradation efficiency and rate of DCF over BPCN is a function of initial DCF concentration, pH and anions. Moreover, the BPCN exhibits an excellent reusability which can be effectively photodegrade DCF for at least 5 consecutive cycles. The reactive species of h+ and O2−• play an crucial role in the enhanced photodegradation of DCF, and, therefore, the plausible reaction mechanism and pathway for DCF photodegradation over 1D BPCN are proposed. These results clearly demonstrate that the BPCN is a superior visible-light-driven photocatalyst, and can pave a gateway to develop metal-free 1D nanocatalysts for the photodecomposition of emerging pollutants in water and wastewater.

Molybdenum phosphide (MoP) with dual active sites for the degradation of diclofenac in Fenton-like system

The leaching and non-recoverability of mental ions have always limited the practical application of Fenton-like processes. For the first time, we synthesized molybdenum phosphide (MoP) with dual active sites for the degradation of diclofenac (DCF) in the Fenton-like process. The DCF degradation rate constant (k) of MoP + H2O2 process was calculated to be 0.13 min-1 within 40 min, indicating a highly efficient catalytic ability of MoP. In addition, this catalyst exhibits a stable structure and good activity, which could apply in a broad pH range, different ions solution and real wastewater condition. Accordingly, this efficient catalytic capability may be attributed to the presence of the metal sites Moδ+ and the electron-rich sites Pδ− in MoP, which could induce the generation of hydroxyl radical (•OH) and superoxide radical (•O2−) through electron transfer, resulting in the effective removal of DCF. This study provides an idea for the optimization of Fenton-like technologies and environmental remediation.

Degradation of Diclofenac in Urine by Electro-Permanganate Process Driven by Microbial Fuel Cells

A novel microbial fuel cell-assisted electro-permanganate process (MFC-PM) was proposed for enhanced diclofenac degradation compared to that of the permanganate oxidation process. By utilizing eco-friendly bio-electricity in situ, the MFC-PM process could activate the simultaneous anodic biological metabolism of urea and the cathodic electro-permanganate process. Density functional analysis and experimental evidence revealed the reactive manganese species (Mn(VII)aq, Mn(VI)aq, Mn(V)aq, and Mn(III)aq), generated via single electron transfer, contributed to diclofenac degradation in the cathodic chamber. The sites of diclofenac with a high Fukui index were preferable to be attacked by reactive manganese species, and diclofenac degradation was mainly accomplished through the ring hydroxylation, ring opening, and decarboxylation processes. Biological detection revealed clostridia were the primary electron donor in the anode chamber in an anaerobic environment. Furthermore, maximum output power density of 1.49 W m−3 and the optimal removal of 94.75% diclofenac were obtained within 20 min under the conditions of pH = 3.0, [DCF]0 = 60 µM, and [PM]0 = 30 µM. Diclofenac removal efficiency increased with external resistance, higher PM dosage, and lower catholyte pH. In addition, the MFC-PM process displayed excellent applicability in urine and other background substances. The MFC-PM process provided an efficient and energy-free bio-electricity catalytic permanganate oxidation technology for enhancing diclofenac degradation.

ABTS as an electron shuttle to accelerate the degradation of diclofenac with horseradish peroxidase-catalyzed hydrogen peroxide oxidation

Horseradish peroxidase (HRP)-catalyzed hydrogen peroxide (H2O2) oxidation could degrade a variety of organic pollutants, but the intrinsic drawback of slow degradation rate limited its widespread application. In this study, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) was introduced into HRP/H2O2 system as an electron shuttle to enhance diclofenac degradation under neutral pH conditions. The green-colored ABTS radical (ABTS•+), generated by the oxidation of ABTS with HRP-catalyzed H2O2 oxidation, was proved to be the main reactive species for the rapid degradation of diclofenac in HRP/H2O2/ABTS system. There was no destruction of ABTS/ABTS•+ in HRP/H2O2/ABTS system, and ABTS was verified as an ideal electron shuttle. The reaction conditions including solution pH (4.5–10.5), HRP concentration (0–8 units mL−1) and H2O2 concentration (0–500 μM) would impact the formation of ABTS•+, and affect the degradation of diclofenac in HRP/H2O2/ABTS system. Moreover, compared with Fenton and hydroxylamine/Fenton systems, HRP/H2O2/ABTS system had better diclofenac degradation efficiency, higher H2O2 utilization efficiency and stronger anti-interference capacity in actual waters. Overall, the present study provided a meaningful and promising way to enhance the degradation of organic pollutants in water with HRP-catalyzed H2O2 oxidation.

Removal of diclofenac in water using peracetic acid activated by zero valent copper

In this work, the degradation kinetics and mechanism of diclofenac (DCF) using peracetic acid (PAA) activated by zero valent copper (ZVC) were systematically investigated. It was found that PAA could be catalyzed effectively by ZVC to produce HO•, CH3COO• and CH3COOO•, which were responsible for the removal of DCF. Based on the XPS, XRD and FESEM characterization results of ZVC before and after reaction, the corrosion of ZVC was occurred to produce Cu+ under acidic condition, which was the main activator for PAA, H2O2 and O2. The recommended pH for this reaction system was 3.0, and DCF degradation was enhanced gradually with increasing ZVC dose and PAA dose. The existence of Cl-, CO32–, Fe3+, Cu2+ and dissolved organic matter (DOM) promoted DCF degradation in ZVC/PAA system, while SO42- and NO3– had almost no influence on DCF removal. Six intermediates were identified in this system, and the probable degradation mechanism of DCF was thus proposed, including seven transformation pathways, i.e., hydroxylation, amidation, dechlorination-cyclizaiton, dechlorination-hydrogenation, dechlorination-hydroxylation, decarboxylation and formylation. This study provides a new method for PAA activation and DCF removal from the polluted water.

Evaluation of diclofenac degradation effect in “active” and “non-active” anodes: A new consideration about mineralization inclination

This work investigates the electrochemical oxidation (EO) of diclofenac (DCF) in water with Ti/Ti4O7, Ti/Ru–Ir, Ti/Sb–SnO2 and Ti/PbO2 electrodes. Scanning electron microscope and X-ray diffraction results suggest that Ti/Ti4O7 has porous stacked surface morphology and Ti/Sb–SnO2 possesses the smallest grain size. Linear sweep voltammetry test results indicate that PbO2 has the highest oxygen evolution potential, while Ti/Ti4O7 and Ti/Ru–Ir show better oxygen evolution activity. DCF degradation results reveal that PbO2 possessed the highest DCF removal (RDCF = 99.2%) and chemical oxygen demand (COD) removal (RCOD = 97.0%), the fastest COD degradation rate (k = 0.0275 min−1, R2 = 0.964), the lowest specific energy consumption (ECDCF = 1.81 kWh.g DCF−1, ECTOC = 6.90 kWh.g TOC−1). The toxicity variation of DCF during EO process on PbO2 is rise first and then to fall. Considering the differences of the four electrodes in residual, conversion and mineralization aspects, mineralization selectivity (MS) was proposed to estimate the mineralization inclination of electrodes during EO process, and PbO2 displays the strongest mineralization inclination (MS = 0.594). In addition, the possible degradation pathway of DCF on PbO2 electrode indicates a composite behavior of conversion and mineralization. All of them above indicate the promising application potential of PbO2 in lower concentration pharmaceuticals and personal care products wastewater treatment. Moreover, MS could be employed as a supplementary index to assess the different inclinations of this composite behavior on various electrodes used for electrochemical treatment of organics in later studies.

Enhanced degradation of pharmaceuticals and personal care products (PPCPs) by three-dimensional electrocatalysis coupled biological aerated filter

Pharmaceuticals and personal care products(PPCPs) were frequently detected in water bodies which were harmful to human health and environment. Three-dimensional electrocatalysis coupled biological aerated filter(3D-EBAF) was developed on the basis of biological aerated filter (BAF)，which could enhance remove rate of pharmaceuticals and personal care products(PPCPs). The effects of the current intensity and kinetic analysis on the removal of diclofenac and clofibric acid in the three-dimensional electrocatalysis coupled biological aerated filter(3D-EBAF) were investigated. Results indicated that (1)average 71.91% of diclofenac at 0.73 mA cm−2 and 58.92% of clofibric acid at 0.64 mA cm−2 could be removed in three-dimensional electrocatalysis coupled biological aerated filter(3D-EBAF), which represented increase by 42.79% and 17.52%, compared with the biological aerated filter(BAF).(2)the degradation of diclofenac and clofibric acid followed first-order kinetic plot in three-dimensional electrocatalysis coupled biological aerated filter(3D-EBAF) and the kinetic rate constant (k) reached a peak of 0.0086 and 0.0052 min−1 at 0.64 mA cm−2.(3)the contributions of removal routes, intermediate products and mechanism were explored. These results indicated that the adsorption, electrocatalytic oxidation, and biodegradation play a synergistic role in the removal of diclofenac and clofibric acid. Three-dimensional electrocatalysis coupled biological aerated filter (3D-EBAF) significantly enhanced the removal rates of pharmaceuticals and personal care products(PPCPs) compared to biological aerated filter(BAF). The application of three-dimensional electrocatalysis biological aerated filter(3D-EBAF) could achieve satisfactory results in the removal of pharmaceuticals and personal care products(PPCPs), which provided an environmentally acceptable and cost-effective technology for the treatment of pharmaceuticals and personal care products (PPCPs).

Enhanced photocatalytic degradation of Diclofenac with Agl/CeO2: A comparison with Mn, Cu and Ag-doped CeO2

Diclofenac, an emerging pollutant, has long half-life and can lead to antibiotic resistance, destruction of aquatic ecosystem, etc. We studied the photocatalytic destruction of diclofenac using ceria synthesized through combustion synthesis and sol gel methods. The combustion synthesis method gives a catalyst with a higher surface area, though with a lower photoactivity. Sol gel ceria was then doped with metal ions: Mn, Cu, Ag to give metal-semiconductor and with AgI to give n-p semiconductor-semiconductor heterojunction photocatalysts. Mn/CeO2, Cu/CeO2 and Ag/CeO2 showed lower photoactivity, while AgI/CeO2 showed better activity over the native CeO2. Over 97% removal of diclofenac was obtained in less than 120 min using 125 W UV light. A 2.6-fold increase in the quantum efficiency was obtained on doping CeO2 with AgI. The enhanced activity of AgI-doped CeO2 is attributed to improved charge separation of electron-hole pairs generated on irradiation with UV light.

High interfacial charge carrier separation in Fe3O4 modified SrTiO3/Bi4O5I2 robust magnetic nano-heterojunction for rapid photodegradation of diclofenac under simulated solar-light

Solar-light powered environmental detoxification is surely a promising and sustainable approach for common goals of human development and ecosystem preservation. Focussing on this, we herein report fabrication of a novel solar active heterojunction Fe3O4@SrTiO3/Bi4O5I2 an in-situ hydrothermal route. The heterojunction was used for the degradation and mineralization of anti-inflammatory drug Diclofenac (DCF) as target pollutant under simulated solar-light irradiation. Current results reveal that the optimized junction displayed 98.4% diclofenac removal in 90 min with 87.2% mineralization. The ESR probe suggests that both ●OH and ●O2− radicals are active species involved in DCF degradation. Analysing the band structure, thermodynamic feasibility and the photocatalytic performance, a traditional mechanism was ruled out and a Z-scheme transfer was predicted. The charge separation was obviously drastically improved by the Z-scheme transfer and facilitation by Fe3O4 and Ti4+/Ti3+ in-built redox mediator. A degradation route was predicted on basis of intermediates detected by liquid-chromatography mass spectrometry analysis. This work promises to provide future possibilities for rational designing and fabrications of semiconductor heterojunctions for solar environmental applications.