Preliminary insights on the development of a continuous-flow solar system for the photocatalytic degradation of contaminants of emerging concern in water.

The ubiquity and impact of pharmaceuticals and pesticides, as well as their residues in environmental compartments, particularly in water, have raised human and environmental health concerns. This emphasizes the need of developing sustainable methods for their removal. Solar-driven photocatalytic degradation has emerged as a promising approach for the chemical decontamination of water, sparking intensive scientific research in this field. Advancements in photocatalytic materials have driven the need for solar reactors that efficiently integrate photocatalysts for real-world water treatment. This study reports preliminary results from the development and evaluation of a solar system for TiO2-based photocatalytic degradation of intermittently flowing water contaminated with doxycycline (DXC), sulfamethoxazole (SMX), dexamethasone (DXM), and carbendazim (CBZ). The system consisted of a Fresnel-type UV solar concentrator that focused on the opening and focal point of a parabolic trough concentrator, within which tubular quartz glass reactors were fixed. Concentric springs coated with TiO2, arranged one inside the other, were fixed inside the quartz reactors. The reactors are connected to a raw water tank at the inlet and a check valve at the outlet. Rotating wheels at the collector base enable solar tracking in two axes. The substances (SMX, DXC, and CBZ) were dissolved in dechlorinated tap water at a concentration of 1.0 mg/L, except DXM (0.8 mg/L). The water underwent sequential batch (~ 3 L each, without recirculation) processing with retention times of 15, 30, 60, 90, and 120 min. After 15 min, the degradation rates were as follows: DXC 87%, SMX 35.5%, DXM 32%, and CBZ 31.8%. The system processed 101 L of water daily, simultaneously removing 870, 355, 256, and 318 µg/L of DXC, SMX, DXM, and CBZ, respectively, showcasing its potential for real-world chemical water decontamination application. Further enhancements that enable continuous-flow operation and integrate highly effective adsorbents and photocatalytic materials can significantly enhance system performance.

Synergistic effect of Cu-nanoparticles and ß-cyclodextrin functionalized reduced graphene oxide nanocomposite on the adsorptive remediation of tetracycline antibiotics.

Pollution by tetracyclines antibiotics has a great potential risk on human and animal health even at trace levels. Copper nanoparticles immobilized-ß-cyclodextrin functionalized reduced graphene oxide (Cu/ß-CD/rGO) were successfully prepared as an efficient extractor of tetracycline (TC), oxytetracycline (OTC) and doxycycline (DC) antibiotics from different environmental water samples. Tetracyclines (TCs) are strongly deposited in the matrix of Cu/ß-CD/rGO nanocomposite via surface complexation with the Cu-nanoparticles besides the formation of inclusion complexes with ß-cyclodextrin and π-π interaction of reduced graphene oxide. The novel nanocomposite was characterized by HRSEM, TEM, TGA, FT-IR, XPS, and XRD. The optimization of variables such as the pH, contact time, ionic strength and TC concentration were successfully analyzed. The maximum adsorption capacity (qm) of Cu/ß-CD/rGO calculated from the Langmuir isotherm was 403.2 mg.g-1 for TC, 476.2 mg.g-1 for OTC and 434.8 mg.g-1 for DC at 298 K. The removal efficiency was decreased by 3.7% after five adsorption-desorption cycles. The Cu/ß-CD/rGO nanocomposite was applied for removing TCs from tap water and the Nile River water samples. The novel nanocomposite demonstrated fast and highly efficient removing performance for different TCs with low levels and large sample volume.

Quantification of Veterinary Antibiotics in Pig and Poultry Feces and Liquid Manure as a Non-Invasive Method to Monitor Antibiotic Usage in Livestock by Liquid Chromatography Mass-Spectrometry.

Antibiotics are active substances frequently used to treat and prevent diseases in animal husbandry, especially in swine and poultry farms. The use of manure as a fertilizer may lead to the dispersion of antibiotic residue into the environment and consequently the development of antibiotic-resistant bacteria. Most pharmaceutical active ingredients are excreted after administration, in some cases up to 90% of the consumed dose can be found in the feces and/or urine as parent compound. Therefore, due to antibiotic metabolism their residues can be easily detected in manure. This article describes a method for simultaneous analysis of ciprofloxacin, chlortetracycline, doxycycline, enrofloxacin, lincomycin, oxytetracycline, tetracycline, tiamulin, trimethoprim and tylosin in feces, liquid manure and digestate. Antibiotics were extracted from the different matrices with McIlvaine-Na2EDTA buffer solution and the extract was purified by the use two techniques: d-SPE and SPE (Strata-X-CW cartridges) and final eluent was analyzed by LC-MS and LC-MS/MS. The European Commission Decision 2002/657/EC was followed to conduct the validation of the method. Recoveries obtained from spiked pig and poultry feces and liquid manures samples ranged from 63% to 93% depending on analytes. The analysis of 70 samples (feces, liquid manure and digestate) revealed that 18 samples were positive for the presence of doxycycline, oxytetracycline, tetracycline, chlortetracycline, enrofloxacin, tiamulin and lincomycin. The results obtained in the presented study demonstrated that animal feces can be used as a non-invasive method detection antibiotic usage in animal production.

A ferrofluidic hydrophobic deep eutectic solvent for the extraction of doxycycline from urine, blood plasma and milk samples prior to its determination by high-performance liquid chromatography-ultraviolet.

The ferrofluid phase was prepared according to mixing magnetic nanoparticle and the hydrophobic deep eutectic solvent as a green microextraction solvent. This new composite was applied for vortex-assisted dispersive liquid-liquid microextraction (VA-HDES-ferrofluid-DLLME) of doxycycline (DOC) residual extraction and determined through high-performance liquid chromatography-ultraviolet (HPLC-UV). The characterization of magnetic nanoparticle was investigated by XRD, TEM and FESEM. The dependency of DOC microextraction to main variables and their interaction and find optimum points were undertaken using response surface methodology with either central composite design (CCD). Thus, the optimum pH, ionic strength, ferrofluid volume and vortex time for DOC extraction are determined to be 3.0, 4%w/v, 150 µL and 7 min, respectively. According to this condition, linear response is found to be greater than 10-400 ng mL-1, with a correlation coefficient of 0.983. The detection and quantification limits are 3.6 and 8.5 ng mL-1, while the repeatability and reproducibility as precision criteria (RSD%) are 3.74% and 4.15%, respectively. The DOC recoveries in all of the urine, blood plasma and milk samples are between 86.70 and 97.48%, with RSD% lower than 5.72%.

Removal of veterinary antibiotics from wastewater by electrocoagulation.

The aim of this study was to assess the effectiveness of veterinary antibiotic removal from wastewater using an electrocoagulation method. The removal efficiency of ampicillin, doxycycline, sulfathiazole and tylosin; the antibiotic degradation degree after electrolysis; and the toxicity and qualitative composition of antibiotic solutions after electrocoagulation were determined in the experiments. HPLC-QTOF was used for quantitative and qualitative determination. The eco-toxicity was assessed using the MARA® assay. After electrocoagulation, the concentration of ampicillin, doxycycline, sulfathiazole and tylosin in wastewater decreased 3.6 ± 3.2%, ∼100%, 3.3 ± 0.4% and 3.1 ± 0.3%, respectively. Doxycycline was the only antibiotic effectively removed from wastewater during electrocoagulation. Simultaneously, part of this antibiotic underwent oxidative degradation. As a result of this process, the eco-toxicity in the reaction environment decreased.

Facile synthesis of Cu(II) impregnated biochar with enhanced adsorption activity for the removal of doxycycline hydrochloride from water.

In this study, the effect factors and mechanisms of doxycycline hydrochloride (DOX) adsorption on copper nitrate modified biochar (Cu-BC) was investigated. Cu-BC absorbent was synthesized through calcination of peanut shells biomass at 450°C and then impregnation with copper nitrate. The Cu-BC has exhibited excellent sorption efficiency about 93.22% of doxycycline hydrochloride from aqueous solution, which was double higher than that of the unmodified biochar. The experimental results suggest that the adsorption efficiency of DOX on the Cu-BC is dominated by the strong complexation, electrostatic interactions between DOX molecules and the Cu-BC samples. Comprehensively considering the cost, efficiency and the application to realistic water, the Cu-BC hold the significant potential for enhancing the effectiveness to remove DOX from water.

Inhibition of biomass activity in the via nitrite nitrogen removal processes by veterinary pharmaceuticals.

The inhibitory effect of two veterinary pharmaceuticals was studied for different types of biomass involved in via nitrite nitrogen removal processes. Batch tests were conducted to determine the inhibition level of acetaminophen (PAR) and doxycycline (DOX) on the activity of short-cut nitrifying, denitrifying and anoxic ammonium oxidation (anammox) biomass and phosphorus accumulating organisms (PAOs). All biomass types were affected by PAR and DOX, with anammox being the most sensitive bacteria. DOX inhibited more the biomass treating high strength nitrogenous effluents (HSNE) than low strength nitrogenous effluents (LSNE). The phosphorus uptake inhibition under anoxic conditions was lower than 25% in the presence of PAR up to 400 mg L(-1). The same DOX concentration inhibited anoxic phosphorus uptake more than 65% for biomass treating LSNE and HSNE. Heterotrophic denitrifying bacteria seem to be more robust at high DOX and PAR concentrations than anammox. Both veterinary products inactivated ammonium oxidizing, Accumulibacter phosphatis and denitrifying bacteria.

RP-HPLC/pre-column derivatization for analysis of omeprazole, tinidazole, doxycycline and clarithromycin.

A validated, reliable and accurate reversed-phase high performance liquid chromatographic method using pre-column derivatization was adopted for the simultaneous determination of two ternary mixtures containing omeprazole, tinidazole and doxycycline hyclate or clarithromycin. Separation was achieved on a C18 column, through a gradient elution system using acetonitrile-methanol-water adjusted to pH = 6.60. Drugs were detected at 277 nm over concentration ranges of 1-112, 5-125, 2.5-550 and 2.5-100 µg/mL for omeprazole, tinidazole, doxycycline hyclate and clarithromycin, respectively. This is the first method that has isolated and identified clarithromycin derivative by infrared and mass spectroscopy. This method is the first study for the simultaneous determination of omeprazole, tinidazole, doxycycline hyclate and clarithromycin in combined mixtures and pharmaceutical formulations.

Adsorption and removal of tetracycline antibiotics from aqueous solution by graphene oxide.

Significant concerns have been raised over pollution of antibiotics including tetracyclines in aquatic environments in recent years. Graphene oxide (GO) is a potential effective absorbent for tetracycline antibiotics and can be used to remove them from aqueous solution. Tetracycline strongly deposited on the GO surface via π-π interaction and cation-π bonding. The adsorption isotherm fits Langmuir and Temkin models well, and the theoretical maximum of adsorption capacity calculated by Langmuir model is 313 mg g(-1), which is approximately in a close agreement with the measured data. The kinetics of adsorption fits pseudo-second-order model perfectly, and it has a better rate constant of sorption (k), 0.065 g mg(-1) h(-1), than other adsorbents. The adsorption capacities of tetracycline on GO decreased with the increase in pH or Na(+) concentration. The adsorption isotherms of oxytetracycline and doxycycline on GO were discussed and compared.

Application of advanced oxidation processes to doxycycline and norfloxacin removal from water.

Doxycycline (Dxy) and Norfloxacin (Nfx) have been oxidized by means of different technologies of increasing complexity. Preliminary experiments showed that activated carbon adsorption (1.0 g L⁻¹) of these antibiotics (C(Antibiotic) = 5 × 10⁻5 M) led to a 60 and 85 % of total organic carbon (TOC) removal, however, a significant decrease in adsorption capacity was experienced after several reuses of the adsorbent. UV-C irradiation of Dxy (20 % removal in 2 h) or Nfx (90 % removal in 2 h) did not affect the initial TOC content of the solution while single ozonation (C(O3) gas inlet concentration = 15.0 ppm) led to the instantaneous disappearance of the parent compounds while TOC conversion values in the proximity of 40 % were obtained. Complex systems based on the combination of ozone, UV-C radiation, titanium dioxide and activated carbon led to similar TOC removals of the order of 70 and 65 % for Dxy and Nfx, respectively. An attempt has been made to calculate the quantum yield and direct ozonation rate constants for doxycycline and norfloxacin. Additionally, the best systems, i.e., the O3 and O3/UV-C processes, have been simulated by a pseudoempirical model by considering TOC as a surrogate parameter.