Removal Of Antibiotics Research Articles

Sorbents utilizing h-BN micro- and nanoparticles for efficient antibiotic removal in wastewater treatment

Currently, there is a high demand for novel sorbents for wastewater treatment. Nanostructured materials are often considered as more promising sorbents compared to their microsized counterparts, which, however, requires experimental verification. In this work, two types of h-BN materials (micro- and nanosized) are compared as candidates for antibiotic sorption. The initial h-BN was in the form of microsized pellets. Nanostructurued h-BN was obtained by high energy ball milling of the initial powder. The effect of ball milling on the microstructure, morphology, chemical composition and surface chemical state was investigated by SEM, TEM, STEM, EDX, XRD, XPS, FTIR and BET techniques. Adsorption properties were studied on samples in the form of pellets and powders. Activated carbon powder was used as a reference material. The antibiotic adsorption process was studied using tetracycline and linezolid. The influence of the h-BN structure on the adsorption characteristics was elucidated using DFT calculations.

Insights into enhanced degradation of antibiotic trimethoprim in water using a novel K doped g-C3N4 photocatalyst under vacuum-UV irradiation: Performance and mechanisms

In this work, an innovative strategy combining vacuum ultraviolet (VUV) and K doping graphite carbon nitride (K-g-C3N4) was proposed for antibiotic removal in aqueous. The properties of K-g-C3N4 were systematically characterized by XRD, FT-IR, BET, SEM, UV-vis DRS, and XPS, showing that K-g-C3N4 possessed a larger specific surface and richer functional groups than g-C3N4. The catalytic efficiency of K-g-C3N4 was investigated for the trimethoprim (TMP) removal under VUV irradiation. Compared with UVC photolysis, VUV photolysis, UVC/g-C3N4, VUV/g-C3N4, and UVC/K-g-C3N4 processes, VUV/K-g-C3N4 enhanced the pseudo-first-order reaction rate constant of TMP removal by 2.0–19.7 times and the mineralization rate by 9.0%-38.2%. Electron paramagnetic resonance results and quenching experiments validated that O2•-, •OH, 1O2, h+, and e- were engaged in the VUV/K-g-C3N4 process. The fluorescent spectra of O2•--substituted and •OH-substituted products revealed that the K-g-C3N4 greatly enhanced the quantity of O2•- and •OH during VUV irradiation. The VUV/K-g-C3N4 system produced marginally more H2O2 and •OH than the UVC/K-g-C3N4 system, confirming that K-g-C3N4 predominantly utilized the UVC and other ultraviolet–visible light emitted by the VUV lamp, with VUV having a minor effect. Furthermore, K-g-C3N4 had exceptional stability and reusability, efficiently degrading various contaminants under VUV irradiation. This work offered a comprehensive insight into VUV/K-g-C3N4 process as a novel approach for antibiotic removal from water.

Sustainable and ultrafast antibiotics removal, self-cleaning and disinfection with electroactive metal-organic frameworks/carbon nanotubes membrane

Although conventional nanofiltration (NF) membrane is widely applied in water treatment, it faces the challenges of insufficient selectivity toward emerging contaminants, low permeability and non-sustainable fouling control. Herein, a novel electroactive metal-organic frameworks/carbon nanotubes membrane was constructed by facile and green nanobubbles-mediated non-solvent-induced phase separation (NIPS) strategy for ultrafast antibiotics removal. It presented 3-fold to 100-fold higher permeability (101.3–105.7 L·h−1·m−2·bar−1) without compromising rejection (71.8 %−99.3 %) of common antibiotics (tetracycline, norfloxacin, sulfamethoxazole, sulfamethazine) than most commercial and state-of-the-art NF membranes. The separation mechanism was due to the synergy of loose selective layer with three-dimensional interconnected networks and UiO-66/CNTs with unique pore sieving and charge property. It also presented excellent antibiotics selectivity with high NaCl/tetracycline separation factor of 194 and CuCl2/tetracycline separation factor of 316 for remediation of antibiotics and heavy metal combined pollution. Meanwhile, it possessed efficient anti-fouling, antibacterial and electro-driven self-cleaning ability, which enabled sustainable fouling control and disinfection with short process, low energy and chemical consumption. Furthermore, potential application of UiO-66/CNTs membrane in wastewater reclamation was demonstrated by stable antibiotics rejection, efficient flux recovery and long-term stability over 260 h. This study would provide useful insights into removal of emerging contaminants from water by advanced NF membrane.

Integrating AgFeO2 and Bi5O7I to establish an S-scheme heterojunction with significantly boosted norfloxacin photocatalytic degradation

Developing highly efficient heterojunction photocatalysts for high performance antibiotic removal is of immense importance but still remains a challenge. Herein, AgFeO2-Bi5O7I (AF-BI), a promising oxygen vacancies rich binary S-scheme heterojunction photocatalyst was synthseized via co-precipitation and hydrothermal treatment. The spherical AgFeO2 spheres were uniformly affixed on the nanorods of Bi5O7I via an intimate contact, as verified through electron microscopy. The photodegradation efficiency of optimized 15 %AgFeO2-Bi5O7I (15AF-BI) for norfloxacin (NFX) was 98.2 % (120 min) with apparent rate constant 0.022 min−1 which was 4 times pure AgFeO2. In municipal water, removal efficiency reached 90.4 % and a high 76.1 % and 65.2 % total organic carbon removal in 3 h in visible light and solar light respectively was achieved. The coupling of AgFeO2 and Bi5O7I triggers electron transfer, forming an internal electric field (leading to a directional charge transfer efficient separation of the photo-induced carriers as confirmed by PL, EIS, TPCR results. The validation of existence of S-scheme mechanism and oxygen vacancies was achieved by in-situ X-ray photoelectron spectroscopy (XPS) and EPR analysis. The free radical scavenging experiments and electron spin resonance (ESR) spectroscopy revealed ●OH and ●O2– radicals were the major reactive species involved in the photodegradation process. The heterojunction is magnetic and can be separated under guidance of magnetic field which makes reusability and separation easy. Based on ESR findings, band structure analysis and mass spectrometry NFX degradation route was predicted. This work provides effective potential solution for preparing new magnetic S-scheme heterojunctions for effective antibiotics degradation and further will expand to realm of clean energy storage and conversion.

Laser-induced growth of metal oxide films on quartz tubes for photocatalytic water treatments

A solid-state pulsed laser technique was developed to in situ grow arbitrary immobilized catalysts (Fe3O4, CeO2, WO3 etc.) on the inner surface of quartz tube with robust adhering strength. In a case study, anatase/rutile hetero-phase TiO2 film was deposited to serve as immobilized photocatalysts for the effective removal of antibiotics from aqueous environment. The X-ray absorption spectroscopy, low temperature electron paramagnetic resonance and the density functional theory simulation directly confirm a defect-assisted type-II band alignment was established to facilitate the charge transfer at the hereto-interphase. In addition, the oxygen vacancy enriched anatase phase with greater binding energy towards the dissolved oxygen facilitated the O2– generation. Meanwhile, the rutile phase enriched with Ti3+ could effectively activate the antibiotics to promote the direct h+ mediated oxidation. Such integration of unique atomic vacancies prevent defects from becoming electron-hole recombination centers and consequently extend the lifetime of the photoexcited charge carrier. The degradation mechanism of oxytetracycline was thoroughly examined by ultra-high resolution electrospray time-of-flight mass spectrometry and Fukui function, while the ecological structure–activity relationships program assessed the toxicity of contaminant to the environment. Milewhile, a continuous water treatment apparatus employing the catalytic tubes as reactors was established and demonstrated a ∼ 95 % OTC degradation under the natural sunlight adopting river water as the background. The experimental studies also claimed that ∼ 90 % of the initial activity could be retained after 100 cycles reuse, which permits their great potential for the applicational scenarios.

Construction of a gelatin aerogel catalyst functionalized with LaCoO3 and g-C3N5 for efficient ciprofloxacin degradation via adsorption and peroxymonosulfate activation

Three-dimensional porous gelatin-based aerogels functionalized with LaCoO3 and nitrogen-rich graphitic carbon nitride (g-C3N5) were successfully fabricated via a freeze-drying approach. Herein, the gelatin-based aerogels served as excellent adsorbents and catalysts activating peroxymonosulfate (PMS) to efficiently degrade ciprofloxacin (CIP) from aqueous solutions. In comparison to the pristine gelatin aerogel (GA), the optimized functionalized aerogel (GA–LCCN-1.5) demonstrated a 17.0% superior CIP adsorption performance. Remarkably, GA–LCCN-1.5 exhibited 95.7% removal efficiency for CIP, attributed to the effective generation of •OH, SO4•−, and 1O2 via PMS activation. In addition, high degradation efficiencies over 84.1% were maintained throughout a broad pH range of 3–9. Notably, GA–LCCN-1.5 demonstrated outstanding stability and reusability, with 93.2% CIP removal efficiency even after five reuse cycles indicating significant promise in real applications. Radical quenching and electron spin resonance (ESR) analysis suggest that CIP degradation was dominated by radical and non-radical routes through GA–LCCN-1.5 catalyzed PMS decomposition. Besides, the plausible CIP degradation mechanisms were systemically analyzed and proposed. The toxicities of CIP and the intermediate by-products were evaluated and reported. The findings of this study and insights demonstrate a facile construction of a biopolymer-based aerogel catalyst for synergistic and efficient PMS activation for the removal of antibiotics in water.

Assessment of the reversibility of resistance in the absence of antibiotics and its relationship with the resistance gene's fitness cost: a genetic study with mcr-1

The intensive use of antibiotics has resulted in strong natural selection for the evolution of antimicrobial resistance (AMR), but whether, and under what circumstances, the removal of antibiotics would result in a rapid reduction in AMR has been insufficiently explored. We aimed to test the hypothesis that in the simple, yet common, case of AMR conferred by a single gene, removing antibiotics would quickly reduce the prevalence of resistance if the AMR gene imposes a high fitness cost and costless resistance is extremely rare among its proximal mutants. In this genetic study, to test our hypothesis, we used the mcr-1 gene in Escherichia coli, which confers resistance to the last-resort antibiotic colistin, as a model. A high-throughput reverse genetics approach was used to evaluate mcr-1 variants for their fitness cost and resistance levels relative to a non-functional construct, by measuring relative growth rates in colistin-free media and at 2 μg/mL and 4 μg/mL colistin. We identified costless resistant mcr-1 mutants, and examined their properties within the context of the sequential organisation of mcr-1's functional domains as well as the evolutionary accessibility of these mutations. Finally, a simple population genetic model incorporating the measured fitness cost was constructed and tested against previously published real-world data of mcr-1 prevalence in colonised inpatients in China since the 2017 colistin ban in fodder additives. We estimated the relative growth rates of 14 742 mcr-1 E coli variants (including the wild type), 3449 of which were single-nucleotide mutants. E coli showed 73·8% less growth per 24 h when carrying wild-type mcr-1 compared with the non-functional construct. 6252 (42·4%) of 14 741 mcr-1 mutants showed colistin resistance accompanied by significant fitness costs, when grown under 4 μg/mL colistin selection. 43 (0·3%) mcr-1 mutants exhibited costless resistance, most of which contained multiple mutations. Among the 3449 single mutants of mcr-1, 3433(99·5%) had a fitness cost when grown in colistin-free media, with a mean relative growth of 0·305 (SD0·193) compared with the non-functional variant. 3059 (88·7%) and 1833 (53·1%) of 3449 single mutants outgrew the non-functional mcr-1 in the presence of 2 μg/mL and 4 μg/mL colistin, respectively. Single mutations that gave rise to costless mutants were rare in all three domains of mcr-1 (transmembrane domain, flexible linker, and catalytic domain), but the linker domain was enriched with cost-reducing and resistance-enhancing mutations and depleted with cost-increasing mutations. The population genetics model based on the experimental data accurately predicts the rapid decline in mcr-1 prevalence in real-world data. Many identified costless resistant variants that consist of multiple mutations are unlikely to evolve easily in nature. These findings for colistin and mcr-1 might be applicable to other cases in which AMR entails a substantial fitness cost that cannot be mitigated in proximal mutants. National Natural Science Foundation of China, and National Key Research and Development Program of China.

Removal of metals and emergent contaminants from liquid digestates in constructed wetlands for agricultural reuse.

Given the increasing pressure on water bodies, it is imperative to explore sustainable methodologies for wastewater treatment and reuse. The simultaneous presence of multiples contaminants in complex wastewater, such as the liquid effluents from biogas plants, can compromise biological treatment effectiveness for reclaiming water. Vertical subsurface flow constructed wetlands were established as low-cost decentralized wastewater treatment technologies to treat the liquid fraction of digestate from municipal organic waste with metals, antibiotics, and antibiotic resistance genes, to allow its reuse in irrigation. Twelve lab-scale planted constructed wetlands were assembled with gravel, light expanded clay aggregate and sand, testing four different treating conditions (liquid digestate spiked with oxytetracycline, sulfadiazine, or ofloxacin, at 100 μg/ L, or without dosing) during 3 months. Physicochemical parameters (pH, chemical oxygen demand (COD), nutrients, metals, and antibiotics), the microbial communities dynamics (through 16S high-throughput sequencing) and antibiotic resistance genes removal (qPCR) were monitored in influents and effluents. Systems removed 85.8%-96.9% of organic matter (as COD), over 98.1% of ammonium and phosphate ions, and 69.3%-99.4% of nitrate and nitrite ions, with no significant differences between the presence or absence of antibiotics. Removal of Fe, Mn, Zn, Cu, Pb and Cr exceeded 82% in all treatment cycles. The treatment also removed oxytetracycline, sulfadiazine and ofloxacin over 99%, and decreased intl1, tetA, tetW, sul1 and qnrS gene copies. Nonetheless, after 3 months of ofloxacin dosing, qnrS gene started being detected. Removal processes relied on high HRT (14 days) and various mechanisms including sorption, biodegradation, and precipitation. Microbial community diversity in liquid digestate changed significantly after treatment in constructed wetlands with a decrease in the initial Firmicutes dominance, but with no clear effect of antibiotics on the microbial community structure. Removals above 85% and 94% were observed for Streptococcus and Clostridium, respectively. Results suggest that vertical subsurface flow constructed wetlands were a suitable technology for treating the liquid digestate to reuse it in irrigation agricultural systems, contributing to the circular bioeconomy concept. However, a more profound understanding of effective wastewater treatment strategies is needed to avoid antibiotic resistance genes dissemination.

Protocatechuic acid enhanced the selective degradation of sulfonamide antibiotics in Fe(III)/peracetic acid process under actually neutral pH conditions

The practical application of the Fe-catalyzed peracetic acid (PAA) processes is seriously restricted due to the need for narrow pH working range and poor anti-interference capacity. This study demonstrates that protocatechuic acid (PCA), a natural and eco-environmental phenolic acid, significantly enhanced the removal of sulfonamide antibiotics in Fe(III)/PAA process under actually neutral pH conditions (6.0–8.0) by complexing Fe(III). With sulfamethoxazole (SMX) as the model contaminant, the pseudo-first-order rate constant of SMX elimination in PCA/Fe(III)/PAA process was 63.5 times higher than that in Fe(III)/PAA process at pH 7.0, surpassing most of the previously reported strategies-enhanced Fe-catalyzed PAA processes (i.e., picolinic acid and hydroxylamine etc.). Excluding the primary contribution of reactive species commonly found in Fe-catalyzed PAA processes (e.g., •OH, R-O•, Fe(IV)/Fe(V) and 1O2) to SMX removal, the Fe(III)-peroxy complex intermediate (CH3C(O)OO-Fe(III)-PCA) was proposed as the primary reactive species in PCA/Fe(III)/PAA process. DFT theoretical calculations indicate that CH3C(O)OO-Fe(III)-PCA exhibited stronger oxidation potential than CH3C(O)OO-Fe(III), thereby enhancing SMX removal. Four potential removal pathways of SMX were proposed and the toxicity of reaction solution decreased with the removal of SMX. Furthermore, PCA/Fe(III)/PAA process exhibited strong anti-interference capacity to common natural anions (HCO3−, Cl−and NO3−) and humic acid. More importantly, the PCA/Fe(III)/PAA process demonstrated high efficiency for SMX elimination in actual samples, even at a trace Fe(III) dosage (i.e., 5 μM). Overall, this study provided a highly-efficient and eco-environmental strategy to remove sulfonamide antibiotics in Fe(III)/PAA process under actually neutral pH conditions and to strengthen its anti-interference capacity, underscoring its potential application in water treatment.

Zeolites and their composites as novel remediation agent for antibiotics: A review

Antibiotic residues in aquatic environments pose significant challenges when exceeding permissible limits. Zeolites, particularly aluminosilicate zeolites, have emerged as effective adsorption materials and solid substrates for semiconductor photocatalysts, facilitating the removal of antibiotics from wastewater. This review highlights the versatility of zeolites and their composites in antibiotic remediation, showcasing recent advancements in adsorption and photocatalytic degradation. Noteworthy examples include Fe (III)-modified synthetic zeolite 13X, exhibiting a maximum tetracycline adsorption capacity of approximately 200 mg/g, and MoS2@Zeolite achieving a remarkable efficiency of 396.70 mg/g for tetracycline removal. Additionally, zeolite-based photocatalysts like Fe-TiO2/BEA zeolite and exceptional CdS/CaFe2O4-clinoptilolite demonstrate high removal percentages, reaching 100% for tetracycline and 86% for cefazolin, respectively. The discussion encompasses an introduction to zeolites, including synthetic and natural zeolites, as well as techniques for modifying natural zeolites. It further delves into the production of synthetic zeolites as well as the fabrication of zeolite-based composite materials. These findings underscore the potential of zeolites and their composites as novel remediation agents for tackling antibiotic contamination in aquatic ecosystems, paving the way for sustainable wastewater treatment strategies. It highlights key elements, distinct qualities, and areas needing further research, paving the way for future studies.

Mechanism of self-supporting montmorillonite composite material for bio-enhanced degradation of chlorotetracycline: Electron transfer and microbial response

The efficient degradation of antibiotics holds significant implications for mitigating environmental pollution. This study synthesized a montmorillonite chitosan composite material (MMT-CS) using the gel template method. Subsequently, a bio-enhanced reactor was constructed to facilitate the degradation of chlorotetracycline (CTC). The addition of MMT-CS composite material enables the degradation of different concentrations of CTC. MMT-CS, a conductive carrier, effectively promotes microbial adhesion and boosts the metabolic activity of functional microorganisms. Additionally, it facilitates the maintenance of microbial activity under CTC pressure by promoting the secretion of extracellular polymeric substances, increasing critical enzyme activity, and enhancing the electron transfer capacity within the system. In this MMT-CS bio-enhanced process, Paracoccus (11.4%) and Bacillus (3.9%) are utilized as essential bacteria genes. The results of metabolic pathways prediction indicated significant enhancements in membrane-transport, nucleotide-metabolism, replication-repair, and lipid-metabolism. Thus, the developed self-supporting MMT-CS bio-enhanced process ensured the stability of the system during the removal of antibiotics.

Optimizing Adsorption‐Redox Sites and Charge Transfer of Ternary Polymer Photocatalyst with P─N Linkage for CO2 Conversion Coupled with Antibiotics Removal

AbstractThe rational design of bifunctional photocatalysts with high adsorption and enrichment characteristics and excellent photocatalytic redox activity is an effective way to address environmental pollution and energy shortage crisis. In this study, cyclophosphazene‐derived porous organic polymer (PCPD) microspheres with P─N linkage are coated with graphene oxide (GO) and loaded with Ag0 nanoparticles (NPs) to prepare covalently bonded xAg‐rGO/PCPD composites. The catalyst with the highest specific surface area (denoted as 2.5Ag‐rGO/PCPD) shows excellent adsorption capacity for fluoroquinolone antibiotics, removing 96.2% of ciprofloxacin (CIP) through adsorption. By applying the catalyst with the best photocatalytic redox activity (denoted as 5Ag‐rGO/PCPD), 82.97% of refractory sulfonamide antibiotics are removed through adsorption‐degradation, and 635.3 µmol g−1 of CO and 162.3 µmol g−1 of CH4 are generated as products of CO2 photoreduction alone. Among the co‐catalytic systems, the highest CO yield of 9.16 µmol g−1 is obtained by coupling CO2 reduction with levofloxacin (LVX) degradation to harness the electron‐donating power of the pollutant molecule. This study is expected to provide useful guidance for the rational design of bifunctional photocatalysts.

Cu inanchored MnO/carbonaceous frameworks trigger peroxymonosulfate activation for enrofloxacin degradation: ROS generation and pollutant attacking processes

Despite Fluoroquinolone antibiotics (FQs) removal in peroxymonosulfate (PMS) activation have been widely researched and the outstanding degradation performance have been gained, the detailed processes by which reactive oxygen species attack pollutants have not been adequately studied. In this study, a Cu/MnO catalyst is anchored onto carbonaceous frameworks using a one-step calcination method for investigation. Benefiting from the sp2 unsaturated carbon as well as the synergistic effect between Cu2+/Cu+/Cu and Mn3+/Mn2+ bimetallic redox electron pairs, the prepared Cu/MnO anchored on carbonaceous frameworks catalyst (4CuMn/C-800) material possesses excellent enrofloxacin (ENR) removal performance, where 85.52 % of ENR is degraded in 80 mins, and maintains relatively high catalysis performance even in the various reaction conditions (reaction pH, reaction temperature, existing anions etc.). The analysis reveals the 1O2 and •O2-, as the dominate ROS, continuously attack the specific active sites of ENR molecules until they are mineralized. In detail, the generated •O2- mainly attacks the piperazine ring, while the formed 1O2 assaults the quinolone group of ENR. By combining density functional theory (DFT) calculations with LC-MS analysis, we propose four distinct pathways for ENR degradation in the 4CuMn/C-800/PMS system. In summary, this study offers a novel and practical approach to design metal/metal oxide/carbon catalysts and enhances our understanding of the mechanisms behind ROS-driven PMS activation.

Magnetic solid phase adsorption of ceftiofur sodium in water by deep eutectic solvent modified banana peel‐MnFe2O4 biochar

AbstractMagnetic solid phase adsorption separation (MSPA) technology is an efficient and convenient separation method, which can simplify the separation step and shorten the separation time. It has wide application value in the purification of antibiotic pollutants in water. In this study, a novel magnetic biochar adsorbent (DES1@MnFe2O4‐BBC) with strong selectivity and high adsorption capacity was synthesized. It was composed of banana peel as the biochar source, Mn/Fe bimetallic oxide as the magnetic source and deep eutectic solvent (DES) as the functional monomer. The physicochemical properties of DES1@MnFe2O4‐BBC were systematically characterized by nitrogen adsorption–desorption, synchronous thermal analyzer, vibrating sample magnetometer, X‐ray diffractometer, X‐ray photoelectron spectroscopy, and field emission electron microscopy. The adsorption conditions were optimized by the single‐factor optimization method. Also, under the optimal adsorption conditions, the maximum adsorption capacity of DES1@MnFe2O4‐BBC for ceftiofur sodium was 75.01 mg·g−1. The test of adsorption thermodynamics and kinetics illustrated that the Langmuir isotherm adsorption model and pseudo‐second‐order kinetic equation were suitable well with the adsorption system established in this article. Adsorbent regeneration cycle experiment revealed that the DES1@MnFe2O4‐BBC was an efficient and reusable adsorbent. In the end, all research proves the novel magnetic adsorbent synthesized in this study can provide a new idea for the removal of antibiotics in water.

Moving Bed Sequenced Batch Reactor System in Tetracycline Antibiotic Removal from Real Hospital Wastewater

Background: Water contamination by synthetic organic chemicals like antibiotics is a major environmental issue. Tetracycline (TC), an antibiotic in a wide family, is notable. A moving bed sequenced batch reactor (MBSBR) is tested for treating hospital raw wastewater containing TC. Methods: A 35-L pilot system was constructed, with 30 L usable. PVC suspended carriers (Kaldnes K3) with 584.3 m2 /m3 specific surface area made about 70% of the functional volume. The independent variables in this study were hydraulic retention duration (1, 1.5, 2, and 2.5 hours) and starting TC concentration (5, 10, and 15 mg/L). Results: The findings of the study demonstrated satisfactory performance under the conditions of an initial TC concentration of 5 mg/L and an organic load of 350 mg/L. The overall removal efficiencies for TC, chemical oxygen demand (COD), and biological oxygen demand (BOD5 ) were 72.8%, 83%, and 93.9%, respectively. The optimal performance of the system was primarily observed during the initial phase, characterized by a TC concentration of 5 mg/L and a hydraulic retention time (HRT) of 2.5 hours. The experimental results also indicated that the maximum removal efficiency was 1.8 kg COD/m2 .day, as determined by a fitted surface loading rate (SLR). Furthermore, the food-tomicroorganism (F/M) ratio decreased from 0.101 to 0.038 as the HRT increased from 1 to 2.5 hours. Conclusion: The results of the study indicate that the MBSBR exhibits a high level of efficiency in removing TC from hospital wastewater.

External carbon source as a viable tool for controlling antibiotics and antibiotic resistance genes (ARGs) in effluent: Influence on antibiotic removal and ARGs dissemination

Fluoroquinolone antibiotics and antibiotic resistance genes (ARGs) regarded as emerging contaminants were poorly removed in conventional wastewater treatment plants (WWTPs). Nitrogen-containing heterocyclic organics were found to be biodegraded through denitrification co-metabolism. The feasibility to enhance antibiotics removal efficiency in WWTPs through denitrification co-metabolism needs to be further verified. Meanwhile, due to significant correlation between ARGs profiles and nitrogen removal that was previously observed, the dissemination of ARGs during denitrification was worthy of in-depth understanding. Herein, the antibiotic removal and ARGs dissemination in denitrification co-metabolism condition were investigated with different denitrifying consortiums that acclimated under different conditions in terms of carbon source and the exposure of Ofloxacin (OFL). The results suggest that the removal of OFL can be enhanced by the denitrification co-metabolism. The tolerance to OFL is different among various denitrifying communities. For the denitrifying consortiums acclimated with methanol, long-term exposure to trace OFL (1 μg/L) could reduce the capabilities of removal and tolerance to OFL. On the contrary, those acclimated with sodium acetate (NaAc), the capabilities of removal and tolerance to OFL, were enhanced by long-term exposure to trace OFL. According to the quantitative determination to 384 target genes with high-throughput quantitative PCR, the abundance of ARGs in consortiums greatly increased when exposed to OFL at the concentration of comparable to sewage, which was also much larger than that acclimated with methanol. It can be confirmed and supported by DNA sequencing results that the antibiotic removal and the dissemination of ARGs were determined by microbial community that could be shaped with carbon source. These conclusions suggest that selecting the right external carbon source can be a useful strategy for WWTPs to control antibiotics and ARGs in the effluent. From a new perspective on mitigating ARGs dissemination, NaAc was not an appropriate carbon source.

Effect of Vehicles and Irrigation Solutions and Methods on Removal of Double Antibiotic Paste from Root Canals: Insights from High-performance Liquid Chromatography Analysis

IntroductionIn regenerative endodontics, eradicating antibiotic residues from root canals is imperative, given their detrimental effects on human apical papilla stem cells. Previous antibiotic removal studies lacked precision in identifying types and quantities of residual antibiotics. High-performance liquid chromatography (HPLC) enhances sensitivity and specificity, enabling accurate detection and quantification of residual drugs. Using HPLC analysis, this study explored the influence of vehicles and irrigation solutions and methods on double antibiotic paste (DAP) removal from root canals. MethodsTwo DAP formulations, each containing 5 mg/mL ciprofloxacin and metronidazole, were created using distinct vehicles: macrogol and propylene glycol (MP) or hydroxypropyl methylcellulose (HPMC). Subsequently, 5 μL of DAP was applied to 200 simulated immature teeth with open apices (n = 100 per formulation) and cultured for 28 days at 37°C. Samples were then divided into 11 groups (n = 20 per group), and canals were irrigated with 17% ethylenediaminetetraacetic acid or 10% citric acid, employing a positive pressure syringe or passive ultrasonic irrigation. The irrigation solution and dentin sample from each tooth were evaluated via HPLC for ciprofloxacin and metronidazole quantification. ResultsCitric acid exhibited significantly superior efficacy in antibiotic removal from root canals, with no observable effect of irrigation methods on drug removal. The HPMC-based DAP formulation significantly enhanced ciprofloxacin removal compared with MP-based DAP. ConclusionsFor antibiotic paste removal from root canals, citric acid is effective, and HPMC is a preferable vehicle over MP. Overall, HPLC is a valuable method for detecting, removing, and quantifying residual antibiotics in root canals.

Cu-TiO2-Aluminosilicate Nanocomposite as Highly Efficient Photocatalyst for Sustainable Removal of Cefixime Antibiotic: Synthesis, Optimization, and Toxicity Evaluation

Cu-TiO2-Aluminosilicate Nanocomposite as Highly Efficient Photocatalyst for Sustainable Removal of Cefixime Antibiotic: Synthesis, Optimization, and Toxicity Evaluation

Surface modified of chitosan by TiO2@MWCNT nanohybrid for the efficient removal of organic dyes and antibiotics

Considering the increase in the discharge of industrial effluents containing dyes and antibiotic resistance as a consequence of increasing the prescription and easy distribution of antibiotic drugs at the global level, designing efficient, biodegradable and non-toxic absorbents is necessary to reduce environmental harm effects. Herein, we present a series of novel eco-friendly ternary hybrid nanocomposite hydrogels CS/TiO2@MWCNT (CTM) composed of chitosan (CS), TiO2, and multiwalled carbon nanotube (MWCNT) for removal of methylene blue (MB) and methyl orange (MO) and common antibiotic ciprofloxacin (CIP) in aqueous medium. The combination of MWCNT and TiO2 improves the physicochemical properties of CS hydrogel and increases the adsorption capacity toward pollutants in the presence of different loadings. CTM hydrogel showed a specific surface area of 236.45 m2 g−1 with a pore diameter of 7.89 nm. Adsorption mechanisms were investigated in detail using kinetic, isotherm, and thermodynamic studies of adsorption as well as various spectroscopic techniques. Adsorption of these pollutants by CTM nanocomposite hydrogel occurred using various interactions at different pHs, which showed the obvious dependence of CTM adsorption capacity on pH. Electrostatic attractions, complex formation, π-π stacking and hydrogen bonds played a key role in the adsorption process. The adsorption of MB, MO, and CIP was fitted with the Langmuir isotherm with maximum adsorption capacities of 531.91, 1763.6, and 1510.5 mg g−1, respectively. CTM had a minor decrease in adsorption strength and showed good structural stability even after 8 adsorptions–desorption cycles. The total cost of producing a 1 kg adsorbent was calculated to be $ 450, which helped us determine the economic feasibility of the adsorbent in large-scale applications.

Efficient removal of ciprofloxacin from aqueous solution using Zn–C battery derived graphene oxide enhanced by hydrogen bonding, electrostatic and π-π interaction

In this study, graphene oxide (GO) derived from waste Zinc–Carbon (Zn–C) batteries was proposed for the efficient removal of antibiotics from the aqueous solution. Ciprofloxacin (CIP) antibiotic was selected as a typical contaminants. GO was prepared via an economical and environment-friendly route by using carbon rods from waste Zn–C batteries as the precursor. Characterization techniques were applied to determine the properties of as prepared GO. Effects of pH, contact time, and adsorbent dose on the adsorption were explored, and an optimum condition was established. Adsorption equilibrium was established in just 20 min for maximum removal of CIP (99.0%) at pH 5.7 for the adsorbent dose of 20 mg L−1 and at the initial concentration of CIP 2.0 mg L−1. The rapid and efficient removal of CIP was greatly influenced by the electrostatic attractions, pi-pi interactions and hydrogen bonding on the surface and edge of GO which was also proved by density functional theory (DFT). Langmuir model showed the best fit among the isotherm models and the calculated maximum adsorption capacity (qm) was 419.62 mg g−1 at 30°C. The kinetic studies also revealed that the adsorption process followed the pseudo-second-order model. The endothermic and spontaneous nature of adsorption was evaluated in thermodynamic studies.