New water based EPD thin BiVO4 film: Effective photocatalytic degradation of Amoxicillin antibiotic.

New thin BiVO4 film using facile water‒based electrophoretic deposition process was synthesized on the webbed stainless steel surface. This work can be considered as a green method owing to use of safe, non-flammable, and cheap media of water as solvent of electrophoretic deposition. Structural and morphological properties of the resultant film were studied by X-ray diffraction (XRD), Raman spectroscopy, Scanning Electron Microscopy (SEM), Elemental and Mapping analyses (EDS), Optical Microscopy, Atomic Force Microscopy (AFM), and X-ray Photoelectron Spectroscopy (XPS) analysis. The moderate diameter size of nanorods of the deposited BiVO4 was measured in the range of 100 to 150 nm. The prepared three layered thin film was shown permanent photocatalytic degradation rate of Amoxicillin pharmaceutical pollution as high as 97.45 % after 90 min. It can be suggested that BiVO4 nanorods have the high ability of hole-electron separation and electron transferring through the alternative routes. Indeed, the prepared thin films of BiVO4 having nanoroad morphology possess great potential for light harvesting. Moreover, webbed stainless steel with electron acceptor character leads to severe separation of photogenerated hole‒electron. The mechanistic study of the scavenging reaction introduced the hydroxyl radicals as the main specie in the photocatalytic process. It is interesting that obtained results of photocatalytic process of this BVO film within different pollutants (dyes, phenol, and drugs) demonstrated the high efficiency and mineralization rate.

Photo-Fenton degradation of amoxicillin via magnetic TiO2-graphene oxide-Fe3O4 composite with a submerged magnetic separation membrane photocatalytic reactor (SMSMPR).

The photo-Fenton process is one of the most important advanced oxidation technologies in environmental remediation. However, the poor recovery of catalysts from treated water impedes the commercialization of this process. Herein, we propose a novel approach for the preparation of TiO2-graphene oxide (GO)-Fe3O4 with high photo-Fenton catalytic performance and capability of magnetic recovery. To realize the recovery of the catalysts, the combination of a submerged magnetic separation membrane photocatalytic reactor (SMSMPR) and TiO2-GO-Fe3O4 was applied to degrade the refractory antibiotic organic compounds in aqueous solution. The results indicate that GO can induce better cycle and catalytic performance of the catalysts. Fe3O4 can not only enhance the heterogeneous Fenton degradation of organic compounds but also provide magnetism of the photocatalyst for magnetic separation from treated water. As a result, the TiO2-GO-Fe3O4 composite in the SMSMPR exhibits excellent photo-Fenton catalytic performance and stability for amoxicillin (AMX) degradation. Both backwashing treatment and magnetic separation in the SMSMPR could enhance the photo-Fenton catalytic activity, durability, and separation properties, promoting practical application of this approach for wastewater treatment. Two possible pathways for AMX photodegradation in the SMSMPR were analyzed by means of a Q-TOF LC/MS system, with most of the intermediates finally mineralized to CO2, water and inorganic ions.

In situ degradation of antibiotic residues in medical intravenous infusion bottles using high energy electron beam irradiation.

This study reported an immediate approach for the degradation of three antibiotic (amoxicillin, ofloxacin, and cefradine) residues in medical intravenous infusion bottles (MIIBs) using high energy electron beam (HEEB) irradiation. The effects of irradiation doses, initial concentrations, initial pH, and scavengers of active radicals on the degradation of three antibiotic residues (ARs) were investigated, and the results displayed that 97.02%, 97.61% and 96.87% of amoxicillin, ofloxacin, and cefradine residues could be degraded in situ through HEEB irradiation respectively. Fourier transform infrared spectroscopy (FTIR) and high performance liquid chromatography-mass spectrometry (HPLC-MS) analysis demonstrated that ARs were mainly decomposed into inorganic ions and alkanes. Typically, the detailed degradation mechanism of ARs was also investigated, and the dominant active particle inducing the degradation of antibiotics during the HEEB irradiation process was demonstrated to be hydroxyl radical.

Homogenous VUV advanced oxidation process for enhanced degradation and mineralization of antibiotics in contaminated water.

This study was aimed to evaluate the degradation and mineralization of amoxicillin(AMX), using VUV advanced process. The effect of pH, AMX initial concentration, presence of water ingredients, the effect of HRT, and mineralization level by VUV process were taken into consideration. In order to make a direct comparison, the test was also performed by UVC radiation. The results show that the degradation of AMX was following the first-order kinetic. It was found that direct photolysis by UVC was able to degrade 50mg/L of AMX in 50min,while it was 3min for VUV process. It was also found that the removal efficiency by VUV process was directly influenced by pH of the solution, and higher removal rates were achieved at high pH values.The results show that 10mg/L of AMX was completely degraded and mineralized within 50s and 100s, respectively, indicating that the AMX was completely destructed into non-hazardous materials. Operating the photoreactor in contentious-flow mode revealed that 10mg/L AMX was completely degraded and mineralized at HRT values of 120s and 300s. it was concluded that the VUV advanced process was an efficient and viable technique for degradation and mineralization of contaminated water by antibiotics.

Fast mineralization and detoxification of amoxicillin and diclofenac by photocatalytic ozonation and application to an urban wastewater.

The degradation of two organic pollutants (amoxicillin and diclofenac) in 0.1 mM aqueous solutions was studied by using advanced oxidation processes, namely ozonation, photolysis, photolytic ozonation, photocatalysis and photocatalytic ozonation. Diclofenac was degraded quickly under direct photolysis by artificial light (medium-pressure vapor arc, λ(exc) > 300 nm), while amoxicillin remained very stable. In the presence of ozone, regardless of the type of process, complete degradation of both organic pollutants was observed in less than 20 min. Photolysis or ozonation on their own led to modest values of total organic carbon (TOC) removal (<6% or 41%, respectively in 180 min), while for photocatalysis (no ozone present) a significant fraction of nonoxidizable compounds remained in the treated water (∼15% after 180 min). In the case of photolytic ozonation, the kinetics of TOC removal was slow. In contrast, a relatively fast and complete mineralization of amoxicillin and diclofenac (30 and 120 min, respectively) was achieved when applying the photocatalytic ozonation process. The absence of toxicity of the treated waters was confirmed by growth inhibition assays using two different microorganisms, Escherichia coli and Staphylococcus aureus. Photocatalytic ozonation was also applied to an urban wastewater spiked with both amoxicillin and diclofenac. The parent pollutants were easily oxidized, but the TOC removal was only as much as 68%, mainly due to the persistent presence of oxamic acid in the treated sample. The same treatment allowed the effective degradation of a wide group of micropollutants (pesticides, pharmaceuticals, hormones and an industrial compound) detected in non-spiked urban wastewater.

Removal of emerging contaminants by simultaneous application of membrane ultrafiltration, activated carbon adsorption, and ultrasound irradiation.

Advanced wastewater treatment is necessary to effectively remove emerging contaminants (ECs) with chronic toxicity, endocrine disrupting effects, and the capability to induce the proliferation of highly resistant microbial strains in the environment from before wastewater disposal or reuse. This paper investigates the efficiency of a novel hybrid process that applies membrane ultrafiltration, activated carbon adsorption, and ultrasound irradiation simultaneously to remove ECs. Diclofenac, carbamazepine, and amoxicillin are chosen for this investigation because of their assessed significant environmental risks. Removal mechanisms and enhancement effects are analysed in single and combined processes. The influence of adsorbent dose and ultrasonic frequency to EC removal are also investigated. Results suggest that adsorption is probably the main removal mechanism and is affected by the nature of ECs and the presence of other components in the mixture. Almost complete removals are achieved in the hybrid process for all ECs.

Photodegradation of amoxicillin in aqueous solution under simulated irradiation: influencing factors and mechanisms.

This paper investigated the effects of selected common chemical species in natural waters (HCO3(-), NO3(-) and humic acids (HA)) on the photodegradation of amoxicillin (AMO) under simulated irradiation using a 300 W xenon lamp. Quenching experiments were carried out to explore the mechanisms of AMO photodegradation. The results indicated that AMO photodegradation followed pseudo-first-order kinetics. Increasing AMO concentration from 100 to 1,000 µg L(-1) led to the decrease in the photodegradation rate constant from 0.2411 to 0.1912 min(-1). The presence of NO3(-) and HA obviously inhibited the photodegradation rate of AMO because they can compete for photons with AMO. Bicarbonate, as a hydroxyl radical (·OH) scavenger, also adversely affected AMO photodegradation. Quenching experiments in pure water suggested that AMO could undergo self-sensitized photooxidation via ·OH and singlet oxygen ((1)O2), accounting for AMO removal of 34.86 and 8.26%, respectively. In HA solutions, the indirect photodegradation of AMO was mostly attributed to the produced ·OH (22.37%), (1)O2 (24.12%) and (3)HA* (20.80%), whereas the contribution of direct photodegradation was to some extent decreased.

Photodegradation of amoxicillin by catalyzed Fe3+/H2O2 process.

Three oxidation processes of UV-Fe3+(EDTA)/H2O2 (UV: ultraviolet light; EDTA: ethylenediaminetetraacetic acid), UV-Fe3+/H2O2 and Fe3+/H2O2 were simultaneously investigated for the degradation of amoxicillin at pH 7.0. The results indicated that, 100% amoxicillin degradation and 81.9% chemical oxygen demand (COD(Cr)) removal could be achieved in the UV-Fe3+ (EDTA)/H2O2 process. The treatment efficiency of amoxicillin and COD(Cr) removal were found to decrease to 59.0% and 43.0% in the UV-Fe3+/H2O2 process; 39.6% and 31.3% in the Fe3+/H2O2 process. Moreover, the results of biodegradability (biological oxygen demand (BOD5)/COD(Cr) ratio) revealed that the UV-Fe3+ (EDTA)/H2O2 process was a promising strategy to degrade amoxicillin as the biodegradability of the effluent was improved to 0.45, compared with the cases of UV-Fe3+/H2O2 (0.25) and Fe3+/H2O2 (0.10) processes. Therefore, it could be deduced that EDTA and UV light performed synergetic catalytic effect on the Fe3+/H2O2 process, enhancing the treatment efficiency. The degradation mechanisms were also investigated via UV-Vis spectra, and high performance liquid chromatography-mass spectra. The degradation pathway of amoxicillin was further proposed.

Removal of amoxicillin by UV and UV/H2O2 processes.

The degradation of the ß-lactam antibiotic amoxicillin (AM) treated with direct UV-C and UV/H(2)O(2) photolytic processes was investigated in the present study. In addition, the antibacterial activity of the solution treated by UV/H(2)O(2) advanced oxidation was compared with AM solution treated with ozone. The degradation rate of amoxicillin in both processes fitted pseudo first-order kinetics, and the rates increased up to six fold with increasing H(2)O(2) addition at 10mM H(2)O(2) compared to direct photolysis. However, low mineralization was achieved in both processes, showing a maximum of 50% TOC removal with UV/H(2)O(2) after a reaction time of 80min (UV dose: 3.8×10(-3)EinsteinL(-1)) with the addition of 10mM H(2)O(2). The transformation products formed during the degradation of amoxicillin in the UV and UV/H(2)O(2) processes were identified by LC-IT-TOF analysis. In addition, microbial growth inhibition bioassays were performed to determine any residual antibacterial activity from potential photoproducts remaining in the treated solutions. An increase of the antibacterial activity in the UV/H(2)O(2) treated samples was observed compared to the untreated sample in a time-based comparison. However, the UV/H(2)O(2) process effectively eliminated any antibacterial activity from AM and its intermediate photoproducts at 20min of contact time with a 10mM H(2)O(2) dose after the complete elimination of AM, even though the UV/H(2)O(2) advanced oxidation process led to bioactive photoproducts.

Degradation of amoxicillin in aqueous solution using sulphate radicals under ultrasound irradiation.

Degradation of the antibiotics amoxicillin in aqueous solution using sulphate radicals under ultrasound irradiation was investigated. The preliminary studies of optimal degradation methodology were conducted with only oxone (2KHSO(5) · KHSO(4) · K(2)SO(4)), cobalt activated oxone (oxone/Co(2+)), oxone+ultrasonication (oxone/US) and cobalt activated oxone+ultrasonication (oxone/Co(2+)/US). The chemical oxygen demand (COD) removal efficiency were in the order of oxone

Kinetic and mechanistic aspects of sensitized photodegradation of ß-lactam antibiotics: microbiological implications.

Amoxicillin (Amx) and cephalexin (Cfx) are ß-lactam antibiotics widely used in human and veterinary medicine. Two points of interest surrounding these molecules are the photodegradation of the molecules and their microbiological implications, as well as the persistence and bioaccumulation in the environment which may cause resistance to bacterial strains. The kinetic and mechanistic aspects of the photosensitized degradation of Amx and Cfx have been studied in water at pH 7.4 and 10 by stationary and time-resolved methods. Kinetic evidence indicates that the Rose Bengal-sensitized photooxidation of Amx at pH 7.4 proceeds via O(2)((1)Δ(g)) and O(2•-) mechanisms while at pH 10 the degradation path occurs, principally, via O(2)((1)Δ(g)). For Cfx, this process is attributed to O(2)((1)Δ(g)) and O(2•-). Photoproducts, which arise from the addition of oxygen atoms and subsequent oxidation of the groups -CH(3) to -COOH, were detected. For both antibiotics the bacteriostatic activity decreases in parallel to their photodegradation. The results of this study could potentially help scientists to better understand and predict the photodegradability of these antibiotics on living organisms and in different environmental compartments.

On the adsorption/photodegradation of amoxicillin in aqueous solutions by an integrated photocatalytic adsorbent (IPCA): experimental studies and kinetics analysis.

Activated carbon-supported TiO(2) nanoparticles, termed integrated photocatalytic adsorbents (IPCAs), were prepared using an ultrasonic impregnation technique and investigated for the photocatalytic degradation of amoxicillin (AMO), a ß-lactam antibiotic. The IPCAs had high adsorption affinity for AMO with the amount adsorbed proportional to the TiO(2) loading and the highest adsorption was at 10 wt% TiO(2) loading. A pseudo-second-order model was found to fit the experimental data and consistently predicted the amount of AMO adsorbed over the adsorption period. Equilibrium isotherm studies showed that the adsorption followed the Redlich-Peterson model with maximum adsorption capacity of 441.3 mg g(-1) for 10% IPCA, 23% higher than the pure activated carbon (AC). Kinetic studies on the photocatalytic degradation of AMO using non-linear regression analysis suggest that the degradation followed Langmuir-Hinshelwood (L-H) kinetics. The adsorption rate constant (K(ad)) was considerably higher than the photocatalytic rate constant (k(L-H)), indicating that the photocatalysis of AMO is the rate-determining step during the adsorption/photocatalysis process. The 10% IPCA exhibited excellent stability and reusability over four photodegradation cycles.

Photosensitized degradation of amoxicillin in natural organic matter isolate solutions.

Amoxicillin is a widely used antibiotic and has been detected in natural waters. Its environmental fate is in part determined by hydrolysis, and, direct and indirect photolysis. The hydrolysis rate in distilled water and water to which five different isolated of dissolved organic matter (DOM) was added, were evaluated. In the five different DOM solutions hydrolysis accounted for 5-18% loss of amoxicillin. Direct and indirect photolysis rates were determined using a solar simulator and it appeared that indirect photolysis was the dominant loss mechanism. Direct photolysis, in a solar simulator, accounted for 6-21% loss of amoxicillin in the simulated natural waters. The steady-state concentrations of singlet oxygen, (1)ΔO(2) (∼10(-13) M) and hydroxyl radical, •OH (∼10(-17) M) were obtained in aqueous solutions of five different dissolved organic matter samples using a solar simulator. The bimolecular reaction rate constant of (1)ΔO(2) with amoxicillin was measured in the different solutions, k(ΔO(2)) = 1.44 × 10(4) M(-1) s(-1). The sunlight mediated amoxicillin loss rate with (1)ΔO(2) (∼10(-9) s(-1)), and with •OH (∼10(-7) s(-1)), were also determined for the different samples of DOM. While (1)ΔO(2) only accounted for 0.03-0.08% of the total loss rate, the hydroxyl radical contributed 10-22%. It appears that the direct reaction of singlet and triplet excited state DOM ((3)DOM(∗)) with amoxicillin accounts for 48-74% of the loss of amoxicillin. Furthermore, the pseudo first-order photodegradation rate showed a positive correlation with the sorption of amoxicillin to DOM, which further supported the assumption that excited state DOM∗ plays a key role in the photochemical transformation of amoxicillin in natural waters. This is the first study to report the relative contribution of all five processes to the fate of amoxicillin in aqueous solution.

Degradation of amoxicillin, ampicillin and cloxacillin antibiotics in aqueous solution by the UV/ZnO photocatalytic process.

The study examined the effect of operating conditions (zinc oxide concentration, pH and irradiation time) of the UV/ZnO photocatalytic process on degradation of amoxicillin, ampicillin and cloxacillin in aqueous solution. pH has a great effect on amoxicillin, ampicillin and cloxacillin degradation. The optimum operating conditions for complete degradation of antibiotics in an aqueous solution containing 104, 105 and 103 mg/L amoxicillin, ampicillin and cloxacillin, respectively were: zinc oxide 0.5 g/L, irradiation time 180 min and pH 11. Under optimum operating conditions, complete degradation of amoxicillin, ampicillin and cloxacillin occurred and COD and DOC removal were 23.9 and 9.7%, respectively. The photocatalytic reactions under optimum conditions approximately followed a pseudo-first order kinetics with rate constant (k) 0.018, 0.015 and 0.029 min(-1) for amoxicillin, ampicillin and cloxacillin, respectively. UV/ZnO photocatalysis can be used for amoxicillin, ampicillin and cloxacillin degradation in aqueous solution.

Degradation of the antibiotics amoxicillin, ampicillin and cloxacillin in aqueous solution by the photo-Fenton process.

The study examined degradation of the antibiotics amoxicillin, ampicillin and cloxacillin in aqueous solution by the photo-Fenton process. The optimum operating conditions for treatment of an aqueous solution containing 104, 105 and 103 mg/L amoxicillin, ampicillin, and cloxacillin, respectively was observed to be H(2)O(2)/COD molar ratio 1.5, H(2)O(2)/Fe(2+) molar ratio 20 and pH 3. Under optimum operating conditions, complete degradation of amoxicillin, ampicillin and cloxacillin occurred in 2 min. Biodegradability (BOD(5)/COD ratio) improved from approximately 0 to 0.4, and COD and DOC degradation were 80.8 and 58.4%, respectively in 50 min. Photo-Fenton treatment resulted in the release and mineralization of organic carbon and nitrogen in the antibiotic molecule. Increase in ammonia and nitrate concentration, and DOC degradation were observed as a result of organic carbon and nitrogen mineralization. DOC degradation increased to 58.4% and ammonia increased from 8 to 13.5mg/L, and nitrate increased from 0.3 to 14.2mg/L in 50 min.

Fate of pharmaceuticals in contaminated urban wastewater effluent under ultrasonic irradiation.

The application of sonolysis (US) for remediation of wastewater is an area of increasing interest. The aim of this study was to evaluate the ultrasonic (US) process on the degradation of pharmaceuticals (diclofenac (DCF), amoxicillin (AMX), carbamazepine (CBZ)) in single solutions and also in three mixtures spiked in urban wastewater effluent. Several operating conditions, such as power density (25-100 W L(-1)), initial substrate concentrations (2.5-10 mg L(-1)), initial solution pH (3-11), and air sparging were varied for the evaluation and understanding of the process. The degradation (as assessed by measuring UV absorbance), the generation of hydroxyl radicals (as assessed measuring H(2)O(2) concentration), the mineralization (in terms of TOC and COD removal), and the aerobic biodegradability (as assessed by the BOD(5)/COD ratio) were monitored during sonication. Ecotoxicity to Daphnia magna, Pseudokirchneriella subcapitata and Lepidium sativum before and after treatment was also evaluated. It was found that the pharmaceuticals conversion is enhanced at increased applied power densities, acidic conditions and in the presence of dissolved air. The reaction rate increases with increasing initial concentration of single pharmaceuticals but it remains constant in the mixtures, indicating different kinetic regimes (i.e. first and zero order respectively). Mineralization is a slow process as reaction by-products are more stable than pharmaceuticals to total oxidation; nonetheless, they are also more readily biodegradable. The toxicity of the wastewater samples before and after contamination with pharmaceuticals both in mixtures and in single substance-containing solutions was observed more severely on P. subcapitata; a fact that raises concerns in regards to the discharge of such effluents. D. magna displayed less sensitivity compared to P. subcapitata because it belongs in a lower taxonomic species than D. magna. The germination index of L. sativum in the presence of the drugs' mixture was stimulated instead of inducing any toxicity effect and this might be attributed to the fact the sample, laden with very low drug concentrations was able to act as a provider of additional nutrient elements.

Amoxicillin sodium-potassium clavulanate: evaluation of gamma radiation induced effects by liquid chromatography on both the individual drugs and their combination.

The effects of gamma irradiation on the stability of potassium clavulanate, amoxicillin sodium and their combination were investigated. A decrease in purity and increase in degradation products up to 30 days after the irradiation were evaluated by reversed phase HPLC. The comparison between unirradiated and irradiated amoxicillin sodium, performed within 24 h following the irradiation process, showed no significant increase in the pre-existing impurities and no evidence of newly induced degradation products. On the contrary, an appreciable increase in the content of some impurities was evidenced 30 days after the irradiation. The chromatographic profile of irradiated potassium clavulanate showed the appearance of one unidentified new product and a slight increase of one pre-existing impurity. No further change in the impurity content was noted 30 days after the irradiation. The amoxicillin sodium-potassium clavulanate combination underwent the same kind of radiation induced degradation as the single compounds.