Sulfanilamide Antibiotics Research Articles

Qualitative and quantitative analysis of electrons donated by pollutants in electron transfer-based oxidation system: Electrochemical measurement and theoretical calculations

In order to gain a profound understanding of the fate of pollutants in advanced oxidation processes (AOPs), this study analyzed the electron contribution of pollutants qualitatively and quantitatively which rarely reported before. The rich electron transfer system was constructed by mesoporous carbon nitride (MCN) coupling with persulfate (PS) driven by visible light and the sulfanilamide antibiotics (SULs) were used as target contaminants. Firstly, the qualitative analysis of electron transfer in the system was confirmed systematically. The electron flow direction tested by i-t curves indicated that PS absorbed electrons, while SULs released electrons. The flow rate of electrons was also accelerated after the addition of SULs. The fitting curve between the kinetics and the peak potential difference tested by CV curve showed that the larger potential difference, the slower rate of oxidative degradation. Secondly, the quantification of electron transfer was achieved through theoretical calculations to simulate the interactions of the ‘catalyst-oxidant-antibiotic’ system. After the addition of SULs, the adsorption energy of the ‘catalyst-oxidant-antibiotic’ system was enhanced and the bond length of the peroxide bond was stretched. Notably, the electron transfer analysis results showed that the charge of SULs was around 0.032–0.056e, indicating that SULs pollutants played the role of electron contributors in the system. The oxidative degradation pathway included the direct cracking of S-N bond, shedding of marginal groups, ring-opening and hydroxyl addition reaction. This study clarified the electronic contribution of SULs in the oxidation system, providing necessary theoretical supplement for the analysis of the transformation of pollutants in AOPs.

The in-situ generation of ClO• by single- and dual-atom catalysis of chloride ions to degrade sulfonamide antibiotics: A DFT study

Single- (SACs) and dual-atom catalysts (DACs) are recognized as promising electrochemical materials. However, their application potential in the water treatment with the presence of chloride ions (the most common water matrice) still needs to be investigated. Thus, the first-principles calculation was used to investigate the electrocatalytic activation of Cl− and micropollutant degradation mechanisms by four kinds of metal-embedded nitrogen-doped carbon materials (M-N-C). The results show that the average Cl− adsorption energies (Eads) in different configurations follow the order of M2N6-a < M2N8 < MN4 < M2N6-b. The average Eads of SACs and DACs doped with different metal atoms follow the order of Fe < Co < Ni and Fe2 < FeNi < FeCo < CoNi ≈ Co2 < Ni2, respectively. The chlorine evolution reactions (CER) on the FeN4 and Fe2N6-a in neutral water were revealed as Cl− → *Cl → HClO* → free HClO, and HClO will rapidly generate ClO• to degrade target pollutants. The generated ClO• exhibits high reactivity towards sulfanilamide antibiotics (SAs) with the reaction rate constants of 1.78 × 108–6.86 × 109 M−1 s−1, indicating the high feasibility of ClO• in SAs purification from wastewater. This study provides mechanistic insights into the electrocatalytic generation of ClO• and its application in removing contaminants of emerging concern in M-N-C-supported electrochemical advanced oxidation processes.

Magnetized algae catalyst by endogenous N to effectively trigger peroxodisulfate activation for ultrafast degraded sulfathiazole: Radical evolution and electron transfer

An innovative Fe–N co-coupled catalyst MN-2 was prepared from waste spirulina by co-pyrolysis as a highly active carbon-based catalyst for the activation of peroxydisulfate (PDS) for the degradation of sulfathiazole (ST). The protein-rich raw material Spirulina provided sufficient N during the pyrolysis process, thus achieving N doping without an additional nitrogen source, optimizing the interlayer structure of the biochar material and effectively inhibiting the leaching of the ligand metal Fe. MN-2 showed highly efficient catalytic activity for peroxydisulfate (PDS), with a degradation efficiency of 100% for ST within 30 min and a kinetic constant (kobs) reached 0.306 min−1, benefiting from the excellent adsorption ability of MN-2 forming MN-2-PDS* complexes and the electron transfer process generated by Fe3+ and Fe2+ cycling, oxygen-containing functional groups. The effects of PDS dosage, initial pH and coexisting anions on the oxidation process were also investigated. Free radical quenching, electron paramagnetic resonance and electrochemical measurements were employed to explain the hydroxyl (·OH) and sulfate (SO4·−) as the dominant active species and the electron transfer effect on the removal of ST. MN-2 maintained a ST removal rate of 84% after four recycling experiments, showing a high reusability performance. This work provides a simple way to prepare magnetized N-doped biochar, a novel catalyst (MN-2) for efficient activation of PDS for ST degradation, and a feasible method for removing sulfanilamide antibiotics in water environment.

Synergistic degradation of Azure B and sulfanilamide antibiotics by the white-rot fungus Trametes versicolor with an activated ligninolytic enzyme system

The treatment of complex polluted wastewater has become an increasingly critical concern for the various types of hazardous organic compounds, including synthetic dyes and pharmaceuticals. Due to their efficient and eco-friendly advantages, the white-rot fungi (WRF) have been applied to degrade environmental pollutants. This study aimed to investigate the removal ability of WRF (i.e., Trametes versicolor WH21) in the co-contamination system composed of Azure B dye and sulfacetamide (SCT). Our study discovered that the decolorization of Azure B (300 mg/L) by strain WH21 was significantly improved (from 30.5% to 86.5%) by the addition of SCT (30 mg/L), while the degradation of SCT was also increased from 76.4% to 96.2% in the co-contamination system. Transcriptomic and biochemical analyses indicated that the ligninolytic enzyme system was activated by the enhanced enzymatic activities of MnPs and laccases, generating higher concentration of extracellular H2O2 and organic acids in strain WH21 in response to SCT stress. Purified MnP and laccase of strain WH21 were revealed with remarkable degradation effect on both Azure B and SCT. These findings significantly expanded the existing knowledge on the biological treatment of organic pollutants, indicating the strong promise of WRF in the treatment of complex polluted wastewater.

Effect of molecular structure on the adsorption behavior of sulfanilamide antibiotics on crumpled graphene balls

Since the 1930s, sulfonamide(SA)-based antibiotics have served as important pharmaceuticals, but their widespread detection in water systems threatens aquatic organisms and human health. Adsorption via graphene, its modified form (graphene oxide, GO), and related nanocomposites is a promising method to remove SAs, owing to the strong and selective surface affinity of graphene/GO with aromatic compounds. However, a deeper understanding of the mechanisms of interaction between the chemical structure of SAs and the GO surface is required to predict the performance of GO-based nanostructured materials to adsorb the individual chemicals making up this large class of pharmaceuticals. In this research, we studied the adsorptive performance of 3D crumpled graphene balls (CGBs) to remove 10 SAs and 13 structural analogs from water. The maximum adsorption capacity qm of SAs on CGB increased with the number of (1) aromatic rings; (2) electron-donating functional groups; (3) hydrogen bonding acceptor sites. Furthermore, the CGB surface displayed a preference for homocyclic relative to heterocyclic aromatic structures. A leading mechanism, π-π electron-donor-acceptor interaction, combined with hydrogen bonding, explains these trends. We developed a multiple linear regression model capable of predicting the qm as a function of SA chemical structure and properties and the oxidation level of CGB. The model predicted the adsorptive behaviors of SAs well with the exception of a chlorinated/fluorinated SA. The insights afforded by these experiments and modeling will aid in tailoring graphene-based adsorbents to remove micropollutants from water and reduce the growing public health threats associated with antibiotic resistance and endocrine-disrupting chemicals.

Fabrication of oxygen doped g‐C3N4 through the formation of a supramolecular precursor for the enhanced photocatalytic degradation of sulfonamides

AbstractBACKGROUNDGraphitic carbon nitrate (g‐C3N4) is considered a promising metal‐free photocatalyst. However, the applications of pristine g‐C3N4 are subject to the high recombination of electron‐hole pairs and low solar utilization. This study aimed to develop a unique and effective method to synthesize oxygen‐doped g‐C3N4 with enhanced photocatalytic activity for pollutant treatment.RESULTSOxygen‐doped g‐C3N4 photocatalysts (CN(M), CN(E), CN(I), and CN(P)) were successfully synthesized via the thermal polycondensation of a novel supramolecular precursor based on urea and monobasic alcohol, in which the urea and alcohol solvent can fully interact through a cross‐linking network fabricated by H‐bonding. The as‐prepared catalysts exhibited enhanced catalytic activity compared with g‐C3N4 on the photocatalytic oxidation of sulfanilamide antibiotics (SMR). The structure of alcohol has an influence on the amount of oxygen doping and on the catalytic activity of oxygen‐doped g‐C3N4; the optimized photocatalytic performance was achieved on CN(I). By combining characterization results, the improved catalytic activity was mainly ascribed to a certain amount of highly electronegative O atoms being doped into the tri‐s‐triazine units of g‐C3N4, which can optimize the basic chemical structure, thus improving light‐harvesting and increasing the separation rate of electron‐hole pairs. In addition, trapping experiments indicated that •O2− is the main active species in the photocatalytic degradation of sulfamethazine.CONCLUSIONThis work provides a facile and efficient approach for the fabrication of an O doped g‐C3N4 catalyst with promising photocatalytic performance on SMR degradation. © 2022 Society of Chemical Industry.

Cotransport of microplastics and sulfanilamide antibiotics in groundwater: The impact of MP/SA ratio and aquifer media

The aim of this study was to investigate the effects of the aquifer media, structure type, and initial concentration ratio of contaminants on the cotransport behavior of microplastics (MPs) and sulfanilamide antibiotics (SAs) through a series of one-dimensional column experiments in groundwater. Under a single suspension system, the relative mass recovery rates of fine sand, medium sand, and coarse sand were 25.65%, 37.50%, and 57.91%, respectively. The breakthrough curve of MPs showed a weak and slow upward trend, indicating that the migration of MPs in aqueous media is mainly blocked by the surface. The migration results of different structure type on SAs (ST, SM, SM2, SMX) in a single suspension system indicated that the deposition rate coefficients (kc) of the four SAs were 1.23 × 10−1, 9.09 × 10−2, 1.11 × 10−1, and 8.87 × 10−2. Under a binary suspension system (MPs:ST = 1:1), the maximum effluent concentration (MEC) of MPs in fine sand, medium sand, and coarse sand increased to 0.52, 0.64, and 0.88, respectively, and the relative mass recovery rates of ST were 22.79%, 23.59%, 20.25%. This results show that the coexistence of MPs and SAs significantly promotes the migration of MPs and inhibits that of SAs. It is mainly because of their carrier action, adsorption sites and additional deposit sites for MPs through SAs pre-deposition on media. When the initial concentration ratio was 2:1, the particles had the highest Zeta potential (−48.3 mV) and the highest potential barrier (3200 kBT), leading to the formation of complex aggregates (MPs-SAs-MPs) owing to the aggregation of colloidal MPs. The increase in the volume and number of MPs-SAs co-aggregates on the surface of the media as the initial concentration of MPs increases, which was mainly due to the disappearance of surface blocking effect and the occurrence of filtering maturation effect.

Versatile strategy of sulfanilamide antibiotics removal via microalgal biochar: Role of oxygen-enriched functional groups.

Biochar (BC) adsorption has been widely acknowledged as an efficient approach for the removal of antibiotics. Despite the importance of oxygen-containing functional groups for the antibiotics removal, most of these may be obtained in BC only relying on the addition of oxidants. Herein, an environmentally friendly and oxygen-enriched functional groups adsorbent, namely Chlamydomonas BC (CBC), was fabricated via simple pyrolysis process. Then, the H-bonding, electron donor-acceptor and electrostatic attraction were identified as the main mechanisms regarding sulfathiazole (STZ) adsorption (506.38mg/g). The carbon-oxygen functional groups on the surface of CBC (61%), especially -COOH and -OH, acted as a pivotal component. Additionally, further theoretical calculation led to the observation that STZ exhibited the highest chemical reactivity (η=0.04), strong electron exchange capacity (μ=-0.16), remarkable electron accepting capacity (ω=0.28) and excellent electron transfer efficiency (EHOMO-ELUMO gap=0.29) under the influence of thiazolyl. The electrophilic sulfonamide group and the nucleophilic thiazole were identified as the main active sites of STZ. In summary, the results of this research provide a guiding role for the preparation of adsorbents driven by the structural characteristics of pollutants.

Distinct chemical adsorption behaviors of sulfanilamide as a model antibiotic onto weathered microplastics in complex systems

Having proved to be harmful to plants, fishes and other species, microplastics as an emerging class of pollutants are raising public concern worldwide. Microplastics that harbor invasive substances in aquatic environment have further attracted scientific attention, due to potential synergistic toxicity greater than that produced individually. This study investigates the fundamental aspect of the adsorption behavior of sulfanilamide, one of the mostly adopted and extensively abused antibiotics, to weathered microplastics via hydrophobic interaction in different contexts. By exerting repeated UV-irradiation/temperature-variation, polyamide (PA), polyvinyl chloride (PVC) and polyethylene terephthalate (PET) microplastics are surface-roughed to display deep furrows depending on composition, while preserving the original chemical groups. Kinetics evaluation reveals an adsorption equilibrium achieved in 2 days. Satisfying fitting with pseudo-second-order model indicates chemical adsorption behavior for sulfanilamide onto all the aged microplastics. Probably due to the distinct surface roughness, a characteristic of Langmuir adsorption for the aged PA and PVC was observed with larger adsorption capacities; While the aged PET microplastics with relatively flat surfaces follow Freundlich adsorption model. We clarified the competition of the antibiotic with other species (e.g., salt, surfactant) and enhanced adsorption by interacting with protein in complex systems. These findings suggest limited adsorption of sulfanilamide antibiotics on microplastics in environment, but incremental toxicity of microplastics to organisms and even human beings that intake antibiotics and microplastics from environment and through food chain.

Cotransport of Microplastics (Mps) and Sulfanilamide Antibiotics (Sas) in Groundwater: The Impact of Mp/Sa Ratio and Aquifer Media

Cotransport of Microplastics (Mps) and Sulfanilamide Antibiotics (Sas) in Groundwater: The Impact of Mp/Sa Ratio and Aquifer Media

Anaerobic biodegradation of four sulfanilamide antibiotics: Kinetics, pathways and microbiological studies

Large amounts of sulfanilamide antibiotics (SAs) have been excreted into the manure. In this study, the anaerobic biodegradation of four kinds of SAs including sulfaquinoxaline (SQX), sulfamethoxazole (SMX), sulfamethoxine (SMD) and sulfathiazole (STZ) was investigated. The degradation rates of SQX and STZ decreased with the increase of the concentrations of other organics, but those of SMX and SMD were less affected. The average degradation rates of SAs were in the order of SMX >SMD ≈QX >STZ, with the best degradation rate constants of 0.30125, 0.14752, 0.16696, and 0.06577 /d, respectively. STZ had the greatest effect on the population richness of microbes, whereas SQX had the largest impact on the population diversity. The degradation rates of SAs were positively correlated with the abundances of Proteobacteria and Bacteroidetes, and negatively correlated with the abundance of Firmicutes. The common degradation pathways of SAs were S-N cleavage and substitution. The specific functional groups of SQX, SMX and SMD, including quinoxaline, isoxazole and pyrimidine rings, could be opened, but the thiazole ring of STZ was difficult to be decomposed. After the rings of the specific functional groups were opened, they would be further substituted or decomposed to be products with small molecules.

Biosynthesized Schwertmannite@Biochar composite as a heterogeneous Fenton-like catalyst for the degradation of sulfanilamide antibiotics

Schwertmannite was successfully loaded onto biochar (Sch@BC) using a biosynthetic method. The physicochemical properties and structural morphology of Sch@BC were explored using XRD, SEM, BET, and XPS. The results showed that introducing biochar can effectively prevent the agglomeration of Sch. The catalytic activity of Sch@BC in the Fenton-like degradation of sulfamethoxazole (SMX) was also systematically investigated under different reaction conditions. Under optimum conditions ([SMX] = 10 mg L−1, [H2O2] = 2.0 mM, Sch@BC = 1.0 g L−1 and initial pH = 3.0), the removal efficiencies of the SMX and total organic carbon (TOC) were 100% and 45.9%, respectively, within 60 min of the reaction. The results of the radical scavenger effect and ESR studies suggested that the SMX degradation in the Sch@BC/H2O2 system was dominated by a heterogeneous Fenton-like reaction. The repeated use of Sch@BC for SMX degradation demonstrated its reusability and stability in Fenton-like reactions. There was also speculation about the degradation mechanism and pathways of SMX. Furthermore, under the same conditions, the removal efficiencies of sulfadiazine (SD) and sulfisoxazole (SIZ) under Fenton-like degradation in the Sch@BC system were 91% and 93%. The results provide a theoretical basis and practical guidance for the creation of a new catalyst using biochar as a support material for the degradation of sulfanilamide antibiotics.

Effect of sulfonamides on the dissolved organic matter fluorescence in biogas slurry during anaerobic fermentation according to the PARAFAC analysis

The biogas slurry produced by anaerobic fermentation process contained a large amount of dissolved organic matter (DOM). In this study, the reason for the effect of sulfanilamide antibiotics (SAs) on DOM components was revealed by analyzing the interaction between microbial community structure and DOM composition in the biogas slurry. Four components of DOM, including tyrosine-like, tryptophan-like or xenobiotic-like, Ultraviolet A (UVA) humic-like and UVA marine humic-like substances, were identified from all the samples through fluorescence excitation emission matrix-parallel factor (EEM-PARAFAC) analysis. The most abundant phyla in biogas slurry were identified to be Firmicutes (60.99 %), Bacteroidetes (19.65 %), Proteobacteria (15.33 %) and Actinobacteria (3.15 %). The contents of soluble microbial byproduct-like substances were related to the growth and metabolism of high abundance of bacterial phyla. Firmicutes could lead to the content change of tyrosine-like substance. The content of the xenobiotic-like substance was negatively correlated with the abundances of Bacteroidetes and Proteobacteria. The addition of high concentration SAs inhibited the growth and reproduction of Firmicutes, resulting in the decrease of the content of tyrosine-like substance. The addition of 100 mg/L sulfaquinoxaline and sulfamethoxydiazine reduced the content of tyrosine-like by 47.5 % and 41.2 %, respectively. The change of tryptophan-like groups was opposite to that of the tyrosine-like. However, the addition of sulfamethoxazole had little effect on the content of all the abovementioned substances.

Stress responses and biological residues of sulfanilamide antibiotics in Arabidopsis thaliana.

Sulfonamides (SAs) are antibiotics widely used in clinical practice, livestock and poultry production, and the aquaculture industry. The compounds enter the soil environment largely through livestock and poultry manure application to farmland. SAs not only affect plant growth, but also pose a potential threat to human health through SA residues in plant tissues. In particular, sulfamethoxazole (SMZ) has been classified as a Category 3 carcinogen by the World Health Organization, and thus its soil ecological toxicity and possible health risks are of concern. Using A. thaliana as a model plant, stress responses and biological residues of sulfadiazine (SD), sulfametoxydiazine (SMD), and SMZ were investigated in the present study. Root length and aboveground plant biomass were significantly inhibited by the three types of SA, whereas lateral roots exposed to SMD grew vigorously. The contents of chlorophyll a and chlorophyll b and photosystem II maximum photochemical quantum yield declined with increase in drug concentration, which indicated that exposure to SAs affected photosynthesis and inhibited chlorophyll synthesis in A. thaliana. With increase in drug concentration, reactive oxygen species (ROS) accumulation in the leaves increased significantly. Activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) were activated at low SA concentrations, but increased lipid peroxidation occurred with increase in SA concentration. Of the three compounds, SMZ was the most toxic to A. thaliana, followed by SD, and SMD was the least toxic. The results indicated that the risk of SMD entering an organism through the food chain is greater than that for SMZ and SD.

Simultaneous removal of sulfanilamide and bioelectricity generation in two-chambered microbial fuel cells

Sulfanilamide antibiotics show the highest detection frequencies and concentrations in surface water of China. In this work, we aim to investigate the feasibility of sulfanilamide removal in the anode of two-chambered MFCs and to examine the influence of sulfanilamide on the electricity generation in MFCs. Results show that sulfanilamide can be efficiently removed in the anode of MFCs and exerts exciting positive effect on electricity generation at the studied concentration range (10–30 mg L−1). In comparison with MFCs using glucose as the sole substrate, the peak voltage output is increased by 8.5, 13.9, and 15.7% for addition of 10, 20, and 30 mg L−1 sulfanilamide, respectively. The anode and the cathode polarization curves reveal that the lower anode overpotential with addition of sulfanilamide is responsible for the promoted electric power output of MFCs. Four groups of comparison experiments are conducted. In normal MFCs, sulfanilamide removal efficiency reaches 90% in 96 h, while the removal efficiencies are 58, 10.8, and 7.5% in open-circuit, no co-substrate and abiotic MFCs, respectively. The results of comparison experiments indicate that sulfanilamide removed in MFCs is mainly stemmed from the biocatalytic co-metabolism degradation other than physical adsorption and the current generated in MFCs plays an active role in accelerating the removal efficiency. These experimental results offer theoretical basis for the possibility of the MFCs application on the industrial wastewater treatment containing sulfanilamide and simultaneous electricity generation.