Search

This study evaluated the effectiveness of using nanocomposite (NCs) of xanthan gum grafted polyacrylamide crosslinked Borax - iron oxide nanoparticle (XG-g-pAAm-CL-Borax-IONP) to remove the amoxicillin antibiotic (AMX) from an aquatic environment. To confirm the structural characteristics of the prepared XG-g-pAAm-CL-Borax-IONP NCs, unique characterization methods (XRD, FT-IR, FE-SEM, EDX, BET, TGA, Zeta, and VSM) were used. Adsorption experimental setups were performed with the influence of solution pH (4-9), the effect of adsorbent dose (0.003-0.02 g), the effect of contact time (5-45 min), and the effect of initial AMX concentration (50-400 mg/L) to achieve the most efficient adsorption conditions. Based on the Freundlich isotherm model, XG-g-pAAm-CL-Borax-IONP NCs provided the maximum AMX adsorption capacity of 1183.639 mg/g. This research on adsorption kinetics also established that the pseudo-second-order model (R 2  = 0.991) is outstanding compatibility with the experimental results. AMX adsorption on the NCs may occur through intermolecular hydrogen bonding, diffusion, and trapping into the polymer network. Even after five cycles, these NCs still displayed the best performance. Based on these results, XG-g-pAAm-CL-Borax-IONP NCs may be a viable material for the purification of AMX from contaminated water., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Antibiotics are emerging organic pollutants that have attracted huge attention owing to their abundant use and associated ecological threats. The aim of this study is to develop and use photocatalysts to degrade antibiotics, including tetracycline (TC), ciprofloxacin (CIP), and amoxicillin (AMOX). Therefore, a novel Z-scheme heterojunction composite of g-C 3 N 4 (gCN) and 3D flower-like Bi 2 WO 6 (BW) perovskite structure was designed and developed, namely Bi 2 WO 6 /g-C 3 N 4 (BW/gCN), which can degrade low-concentration of antibiotics in aquatic environments under visible light. According to the Density Functional Theory (DFT) calculation and the characterization results of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FITR), Scanning electron microscopy - energy spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS), this heterojunction was formed in the recombination process. Furthermore, the results of 15 wt%-BW/gCN photocatalytic experiments showed that the photodegradation rates (Rp) of TC, CIP, and AMOX were 92.4%, 90.1% and 82.3%, respectively, with good stability in three-cycle photocatalytic experiments. Finally, the quenching experiment of free radicals showed that the holes (h + ) and superoxide radicals (·O 2 - ) play a more important role than the hydroxyl radicals (·OH) in photocatalysis. In addition, a possible antibiotic degradation pathway was hypothesized on the basis of High performance liquid chromatography (HPLC) analysis. In general, we have developed an effective catalyst for photocatalytic degradation of antibiotic pollutants and analyzed its photocatalytic degradation mechanism, which provides new ideas for follow-up research and expands its application in the field of antibiotic composite pollution prevention and control., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Kai Huang reports financial support was provided by National Natural Science Foundation of China. Kai Huang reports a relationship with Guangdong & Guangxi Cooperation Special Key Fund Project that includes: funding grants. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Antibiotics are now considered as emerging environmental pollutants due to their persistent nature and continuous exposure through irrigation with wastewater contaminated with antibiotics. The aim of present study was to assess the potential of nanoparticles for the photodegradation of antibiotics and subsequent stress alleviation via Titania oxide (TiO 2 ) application for improvement in crop productivity and quality in terms of the nutritional composition. In the first phase, different nanoparticles, TiO 2 , Zinc oxide (ZnO), and Iron oxide (Fe 2 O 3 ) with varying concentrations (40-60 mg L -1 ) and time-periods (1-9 days) were tested to degrade amoxicillin (Amx) and levofloxacin (Lev) @ 5 mg L -1 under the visible light. Results indicated that TiO 2 nanoparticles (50 mg L -1 ) were the most effective nanoparticles for the removal of both antibiotics with maximum degradation of 65% and 56% for Amx and Lev, respectively, on the 7th day. In the second phase, a pot experiment was conducted in which TiO 2 (50 mg L -1 ) was applied individually and along with antibiotics (5 mg L -1 ) in order to evaluate the effect of nanoparticles on stress alleviation for growth promotion of wheat exposed to antibiotics. Plant biomass was reduced by Amx (58.7%) and Lev (68.4%) significantly (p < 0.05) when compared to the control. However, co-application of TiO 2 and antibiotics improved the total iron (34.9% and 42%), carbohydrate (33% and 31%), and protein content (36% and 33%) in grains under Amx and Lev stress, respectively. The highest plant length, grain weight, and nutrient uptake were observed upon application of TiO 2 nanoparticles alone. Total iron, carbohydrates, and proteins in grains were significantly increased by 52%, 38.5%, and 40%, respectively compared to the control (with antibiotics). The findings highlight the potential of TiO 2 nanoparticles for stress alleviation, growth, and nutritional improvement under antibiotic stress upon irrigation with contaminated wastewater., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The impact of electrolytes on the adsorption of emerging pollutants: pharmaceuticals onto layered materials: a raw clay mineral and its nonionic and cationic organoclay derivatives was studied. The selected pharmaceuticals: amoxicillin, norfloxacin, sulfamethoxazole, metoprolol, carbamazepine, and trimethoprim show different electric charges: zwitterionic, anionic, cationic and neutral and hydrophobic character (different LogP). Without any salts, the set of complementary data obtained by UV and infrared spectroscopies, X-ray diffraction points out the importance of the electric charge which represents a key parameter in both the spontaneity and feasibility of the adsorption. In contrast, the hydrophobicity of the analytes plays a minor role but determines the magnitude of the adsorbed amount of pharmaceuticals onto organoclays. With a dual hydrophilic and hydrophobic behavior, nonionic organoclay appears to be the most polyvalent material for the removal of the pharmaceuticals. In the presence of electrolytes (NaCl at a concentration of 1 × 10 -2  mol L -1 ), both nonionic and cationic organoclays show a decrease of their efficiencies, whereas the adsorption is particularly enhanced for Na-Mt except for the cationic species (trimethoprim and metoprolol). Thus, in realistic experimental conditions close to those of natural effluents, raw clay mineral appears as the most appropriate sorbent for the studied pharmaceuticals while it raises the question of the usefulness of organoclays in water remediation strategy., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

This work investigated the electrochemical degradation of amoxicillin (AMX) in aqueous solution with Cu-PbO 2 electrode. The main influence factors on the degradation of AMX, such as Na 2 SO 4 concentration, initial AMX concentration, current density and initial pH value, were analyzed in detail. Under the optimal conditions, the removal rates of AMX and chemical oxygen demand (COD) reached 99.4% and 46.3% after 150 min treatment. The results indicated that the electrochemical degradation of AMX fitted pseudo-first-order reaction kinetics. Compared with undoped PbO 2 electrode, Cu-PbO 2 electrode had a smaller crystal size, more proportion of hydroxyl oxygen species, greater AMX and chemical oxygen demand (COD) removal efficiency, higher average current efficiency (ACE) and lower electrical efficiency per log order (EE/O). Electrochemical oxidation using Cu-PbO 2 electrodes was an effective way to eliminate amoxicillin in aqueous solution. Moreover, a possible degradation pathway including ring open and mineralization was proposed by intermediate products determined by GC-MS method. This paper could provide basic data and technique reference for the amoxicillin wastewater pollution control., (Copyright © 2019. Published by Elsevier Ltd.)

The direct and indirect photodegradation of six cephalosporins was predicted using a photochemical model, on the basis of literature values of photochemical reactivity. Environmental photodegradation would be important in surface water bodies with depth ⩽ 2-3m, and/or in deeper waters with low values of the dissolved organic carbon (DOC ⩽ 1 mg C L(-1)). The half-life times would range from a few days to a couple of weeks in summertime. In deeper and higher-DOC waters and/or in different seasons, hydrolysis could prevail over photodegradation. The direct photolysis of cephalosporins is environmentally concerning because it is known to produce toxic intermediates. It would be a major pathway for cefazolin, an important one for amoxicillin and cefotaxime and, at pH<6.5, for cefapirin as well. In contrast, direct photolysis would be negligible for cefradine and cefalexin. The DOC values would influence the fraction of photodegradation accounted for by direct photolysis in shallow water, to a different extent depending on the role of sensitisation by the triplet states of chromophoric dissolved organic matter., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Despite bimetallic Fe/Ni nanoparticles have been extensively used to remediate groundwater, they have not been used for the catalytic degradation of amoxicillin (AMX). In this study, bentonite-supported bimetallic Fe/Ni (B-Fe/Ni) nanoparticles were used to degrade AMX in aqueous solution. More than 94% of AMX was removed using B-Fe/Ni, while only 84% was removed by Fe/Ni at an initial concentration of 60 mg L(-1) within 60 min due to bentonite serving as the support mechanism, leading to a decrease in aggregation of Fe/Ni nanoparticles, which was confirmed by scanning electron microscopy (SEM). The formation of iron oxides in the B-Fe/Ni after reaction with AMX was confirmed by X-ray diffraction (XRD). The main factors controlling the degradation of AMX such as the initial pH of the solution, dosage of B-Fe/Ni, initial AMX concentration, and the reaction temperature were discussed. The possible degradation mechanism was proposed, which was based on the analysis of degraded products by liquid chromatography-mass spectrometry (LC-MS)., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The bromination of five selected pharmaceuticals (metoprolol, naproxen, amoxicillin, phenacetin, and hydrochlorothiazide) was studied with these compounds individually dissolved in ultra-pure water. The apparent rate constants for the bromination reaction were determined as a function of the pH, obtaining the sequence amoxicillin>naproxen>>hydrochlorothiazide≈phenacetin≈metoprolol. A kinetic mechanism specifying the dissociation reactions and the species formed for each compound according to its pK(a) value and the pH allowed the intrinsic rate constants to be determined for each elementary reaction. There was fairly good agreement between the experimental and calculated values of the apparent rate constants, confirming the goodness of the proposed reaction mechanism. In a second stage, the bromination of the selected pharmaceuticals simultaneously dissolved in three water matrices (a groundwater, a surface water from a public reservoir, and a secondary effluent from a WWTP) was investigated. The pharmaceutical elimination trend agreed with the previously determined rate constants. The influence of the main operating conditions (pH, initial bromine dose, and characteristics of the water matrix) on the degradation of the pharmaceuticals was established. An elimination concentration profile for each pharmaceutical in the water matrices was proposed based on the use of the previously evaluated apparent rate constants, and the theoretical results agreed satisfactorily with experiment. Finally, chlorination experiments performed in the presence of bromide showed that low bromide concentrations slightly accelerate the oxidation of the selected pharmaceuticals during chlorine disinfection., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Antibiotics have increasingly been detected in effluents and the environment. However, information on the degree of deactivation and mineralization, and the nature of possible formed dead-end transformation products is scarce but desirable for proper risk assessment. An important group of antibiotics is the beta-lactams. We studied the transformation of the closely structurally related beta-lactams piperacillin and amoxicillin in two OECD biodegradability batch tests. None of the antibiotics was biodegraded in the closed bottle test (CBT). However, primary abiotic elimination as monitored by HPLC-UV-VIS was 20% and 100% in the CBT within 14 days, respectively. With HPLC-UV-VIS and ion trap LC-MS/MS primary elimination was shown to be more than 94% for both antibiotics within seven days in the Zahn-Wellens test (ZWT). Both compounds were deactivated by hydrolysis. For piperacillin, a dead-end transformation product resulted after hydrolysis of the beta-lactam ring. For amoxicillin full mineralization of the transformation products was observed.

The biological and non-biological factors that affect the degradation of amoxicillin in the composting process of feces have been investigated. The effect of living bacteria and the enzyme (beta-lactamase) on amoxicillin decay was examined, and our results indicated that the biological effects are likely to be negligible. Consequently, the effect of phosphate, ammonia and pH level as non-biological factors was investigated by monitoring the reduction rate of amoxicillin in phosphate and ammonia buffer solutions with several pH levels. Each reduction rate constant was integrated by a simulation model, and the each calculated amoxicillin reduction profile was compared to the reduction profiles of amoxicillin in the composting process of feces. The calculated results corresponded almost exactly to the experimental profiles. We therefore concluded that the degradation of amoxicillin in a toilet matrix was dependent on the concentration of ammonia, phosphate and hydroxyl ion.