Removal Of Antibiotics Research Articles

Advanced Graphene-Based Technologies for Antibiotic Removal from Wastewater: A Review (2016–2024)

The increasing presence of antibiotics in wastewater poses significant environmental risks, including the promotion of antibiotic resistance and harm to aquatic ecosystems. This study reviews advancements in graphene-based technologies for removing antibiotics from wastewater between 2020 and 2024. Graphene-based platforms, such as graphene oxide (GO), reduced graphene oxide (rGO), and graphene composites, have shown great promise in this field because of their exceptional adsorption capacities and rapid photocatalytic degradation capabilities. Functionalized graphene materials and graphene integrated with other substances, such as metal oxides and polymers, have enhanced performance in terms of antibiotic removal through mechanisms such as adsorption and photocatalysis. These technologies have been evaluated under various conditions, such as pH and temperature, demonstrating their practical applicability. Despite challenges related to scalability, cost-effectiveness, and environmental impact, the advancements in graphene-based technologies during this period highlight their significant potential for effective antibiotic removal, paving the way for safer and more sustainable environmental management practices.

In-situ growth of Fe-MOF on magnetic materials by self-template method to enhance practicality and removal of tetracycline antibiotics from aqueous solution

In this work, core–shell structured Fe3O4@PCN-333 (Fe) composite was constructed using a self-template method, in which Fe3O4 microspheres not only serve as magnetic centers but also provide Fe (III) for the preparation of PCN-333 (Fe). PCN-333 (Fe) uniformly grew as a shell on the surfaces of the microspheres, and the shell thickness was approximately 38 nm. The composite exhibited high adsorption performance, with maximum adsorption capacities of 471.7, 303.3 and 314.5 mg/g for chlortetracycline, tetracycline and oxytetracycline, respectively. The adsorption of tetracycline antibiotics (TCs) was based on the Langmuir and pseudo-second-order model, and external diffusion and pore diffusion were the rate-limiting steps in adsorption. The strong adsorption capacity was attributed to the mechanism of π–π interaction, coordination bonds, electrostatic interaction, hydrogen bonding, and van der Waals force. Fe3O4@PCN-333 (Fe) composite displayed good stability in the aqueous solution, strong TCs adsorption capacity, high selectivity, anti-interference performance for adsorbing TCs, fast recovery with external magnetic field, reusability, thus effectively reducing the cost for removing water pollutants. These features make the composite a potential material for removing TCs in the environment.

Preparation of phenol-formaldehyde composite modified with chitosan for the simultaneous removal of antibiotics and heavy metal ions in waters

In current study, a new adsorbent based on aminated phenol-formaldehyde composite was prepared using chitosan as modifier. Various techniques were adopted to characterize the morphology and structure of the prepared adsorbent. Due to the abundant amino groups, the obtained adsorbent presented satisfactory adsorption performance towards fluoroquinolones (FQs) and heavy metal ions (including Cu2+, Cd2+ and Pb2+) by means of multiple forces including electrostatic, H-bonding, π-π stacking interactions (for FQs) and chelating force (for heavy metal ions). Studies about the adsorption kinetics, isotherm and thermodynamics were performed to inspect the adsorption behaviors of studied FQs and heavy metal ions on the new adsorbent. After optimizing the adsorption parameters, the obtained adsorbent were employed to remove FQs, Cu2+, Cd2+ and Pb2+ in various environmental waters. The removal rates for FQs and heavy metal ions were 91.8–98.6 % and 94.4–98.5 %, respectively, which were significantly higher than that obtained on unmodified phenol-formaldehyde resin (20.7–49.0 % for FQs and 35.1–43.0 % for heavy metal ions). At the same time, the adsorbent exhibited good preparation repeatability in different batches, acceptable stability and reusability. The current study well demonstrated the potential application of the new adsorbent in the simultaneous removal of organic and inorganic pollutants from aqueous waters.

A recyclable and high porosity vinasse-based biochar with enhanced superficial active sites for antibiotics recovery

Antibiotic pollution in water bodies is a global environmental issue. For adsorbing antibiotic residues, biochar produced by direct high temperature pyrolysis faces challenges in balancing adsorption capacity and recyclability due to limited active sites. Thus, a recyclable and high-porosity vinasse-based biochar was developed via co-pyrolysis of K2FeO4 one-pot method. The co-pyrolysis biochar's surface area was augmented by 143 times, from 3.4 m²/g to 490.9 m²/g. The maximum theoretical adsorption capacity of the co-pyrolysis biochar for norfloxacin (NOR) increased from 4.4 mg/g to 364.9 mg/g, an approximate 83-fold enhancement. The surface of the biochar was rich in active groups (C-O, C-Fe, and -OH), which acted as the active sites to enhance the adsorption of NOR. The adsorption mechanism involved a variety of interactions, including pore-filling, hydrogen bond, π-π interactions, surface complexation, and electrostatic interactions. Importantly, the biochar is magnetic and can be recycled attributed to the generation of ferriferous oxides during the carbonization. After three cycles of reuse, the adsorption efficiency of vinasse-based biochar for NOR still exceeded 70 %. Such biochar prepared by this facile and feasible co-pyrolysis method show the potential to enhance active sites for removal of antibiotic from aquatic systems.

Stratified nanoflower bimetallic cobalt/iron alloy derived from CoFe-MOFs as efficient peroxymonosulfate activator for antibiotics degradation: Performance, mechanism, and toxicity

Co-based metal-organic framework (Co-MOFs) derivative has gained wide attention in the field of advanced oxidative processes (AOPs). However, the degradation efficiency of single cobalt element remains suboptimal and its activation mechanism still needs to be further explored. In this study, stratified nanoflower bimetallic cobalt/iron alloys (CoFe-NC), derived from cobalt/iron bimetallic-organic frameworks (CoFe-MOFs), was synthesized via self-assembly at room temperature, hydrothermal synthesis and high-temperature carbonization processes and their performance as efficient activators of peroxymonosulfate (PMS) for the degradation of antibiotics was evaluated (removal efficiency of 100 % within 40 min, k=0.0951 min−1). The excellent degradation property benefit by specific nano-flowers structure with high specific surface area (424.67 m2/g), the cycle between Co0→Co2+↔ Co3+ and Fe0→Fe2+↔Fe3+, synergistic effect of Co and Fe bimetals. Furthermore, the CoFe-NC/PMS system exhibits exceptionally high cyclic stability (over 85 % degradation efficiency after four times degradation), a wide range of pH (3−11) and resistance to background ion interference (Cl–, H2PO4–, NO3–, HCO3– and HA), and reduced toxicity of the degradation products. Degradation mechanistic studies demonstrated that the activation of PMS by CoFe-NC generated amounts of reactive oxygen species (ROS) (SO4•−, •OH, •O2− and 1O2). Additionally, high-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis identified fifteen intermediate degradation products and three possible degradation pathways were proposed. The results highlight the potential of CoFe-NC as a catalyst for antibiotic removal, providing insights into the optimization of bimetallic-organic framework for environmental applications.

Removal of Antibiotics by Algae: Elucidating the Removal Mechanisms, Treatment Systems and Post-Treatment Antibiotic Resistance

Removal of Antibiotics by Algae: Elucidating the Removal Mechanisms, Treatment Systems and Post-Treatment Antibiotic Resistance

Periodic polarity reversal triggered sequential electrochemical redox of blue TiO2 nanotube arrays for efficient removal of antibiotics and inorganic nitrogen from actual mariculture wastewater

Using blue TiO2 nanotube arrays (Ti/BTNAs) as both anode and cathode, a novel bipolar system that is suitable for operating in periodic polarity reversal (PR) and flow-through mode was established, aiming to effectively remove antibiotics and inorganic nitrogen from actual mariculture wastewater. Under optimal conditions of 4.0 mA/cm2 current density, 3.0 mL/min water flow rate and 2.0 cycles/h polarity reversal frequency, the PR-induced synergistic effect endows Ti/BTNAs abundant oxygen vacancies (20.53 %), high activity and extended service lifetime (5.25 years), realizing continuous production of surface-adsorbed active hydrogen (Hads∗) at cathode and reactive chlorine species (Cl, ClO, Cl2−, ClO−) over anode through Cl− reacting with reactive oxygen species (HO, SO4−, O2−) and ∼0.7 kWh/gTOC energy consumption. Bipolar system can also flexibly regulate denitrification mechanism through the PR-triggered sequential electrochemical redox of Ti/BTNAs in water flow direction, achieving minimum energy consumption of ∼43.4 ± 3.2 kWh/kg(NH4+-N) and 33.7 ± 2.3 % current efficiency. Berberine antibiotic degradation pathway was suggested by DFT calculations and LC-MS/MS analyses. This study provides a long-acting and low-consuming strategy for comprehensive treating mariculture wastewater.

Removal of sulfamethoxazole in an algal-bacterial membrane aerated biofilm reactor: Microbial responses and antibiotic resistance genes

Antibiotics are frequently detected in wastewater, but often are poorly removed in conventional wastewater treatment processes. Combining microalgal and nitrifying bacterial processes may provide synergistic removal of antibiotics and ammonium. In this research, we studied the removal of the antibiotic sulfamethoxazole (SMX) in two different reactors: a conventional nitrifying bacterial membrane aerated biofilm reactor (bMABR) and algal-bacterial membrane aerated biofilm reactor (abMABR) systems. We investigated the synergistic removal of antibiotics and ammonium, antioxidant activity, microbial communities, antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and their potential hosts. Our findings show that the abMABR maintained a high sulfamethoxazole (SMX) removal efficiency, with a minimum of 44.6 % and a maximum of 75.8 %, despite SMX inhibition, it maintained a consistent 25.0 % ammonium removal efficiency compared to the bMABR. Through a production of extracellular polymeric substances (EPS) with increased proteins/polysaccharides (PN/PS), the abMABR possibly allowed the microalgae-bacteria consortium to protect the bacteria from SMX inactivation. The activity of antioxidant enzymes caused by SMX was reduced by 62.1–98.5 % in the abMABR compared to the bMABR. Metagenomic analysis revealed that the relative abundance of Methylophilus, Pseudoxanthomonas, and Acidovorax in the abMABR exhibited a significant positive correlation with SMX exposure and reduced nitrate concentrations and SMX removal. Sulfonamide ARGs (sul1 and sul2) appeared to be primarily responsible for defense against SMX stress, and Hyphomicrobium and Nitrosomonas were the key carriers of ARGs. This study demonstrated that the abMABR system has great potential for removing SMX and reducing the environmental risks of ARGs.

Palygorskite-mediated simultaneous nutrient removal and antibiotic degradation from aquaculture wastewater in lab-scale constructed wetlands

In this study, palygorskite was employed as a substrate in laboratory-scale constructed wetlands (CWs) over a period of 180 days to investigate the removal efficiency of pollutants from mariculture wastewater under high loads of enrofloxacin (ENR) stress. The results indicated that the incorporation of palygorskite into CWs resulted in average effluent concentrations of total phosphorus (TP), total nitrogen (TN), chemical oxygen demand (COD), and ENR reaching 0.07 ± 0.00 mg/L, 1.07 ± 0.06 mg/L, 11.57 ± 1.04 mg/L, and 0.047 ± 0.002 mg/L, respectively. The removal efficiencies reached 96.45 ± 0.04 %, 94.62 ± 0.27 %, 88.61 ± 1.22 %, and 91.14 ± 5.00 % respectively, with phosphorus removal significantly surpassing that reported for similar CWs. This superior performance was mainly attributed to the strong binding mechanisms between phosphorus and the metal oxides and hydroxides leached from the palygorskite. The palygorskite stimulated the secretion of extracellular polymeric substances (EPS), accelerated biofilm establishment, and enhanced the relative abundance of key functional bacteria associated with carbon, nitrogen, and antibiotic removal, thus achieving rapid denitrification and efficient organic matter removal. Monitoring of metals (Ca, Fe, Mn, and Cu) in the CWs effluent suggested that their presence was insufficient to affect cytoplasmic enzyme activity or cause oxidative stress damage to plants. In conclusion, palygorskite serves as an environmentally friendly, high-nutrient removal alternative, apt as a substrate for CWs.

Design of CdZnS/BiOCl heterostructure as a highly-efficient piezo-photocatalyst for removal of antibiotic

Facilitating the surface and bulk photocarrier separation in semiconductors is crucially important for enhancing their photocatalytic activities. In this study, we have immobilized CdxZn1−xS (x = 0.7) nanoparticles on the surface of (001)-facet-exposed BiOCl (BOC) nanosheets to form heterostructured CZS/BOC piezo-photocatalysts. Experiments and theories were performed to unveil the piezo-photocatalytic performances of the CZS/BOC heterostructures and involved mechanisms. It is corroborated that the CZS/BOC heterostructures exhibit efficient transfer/separation of photocarriers, and hence possess excellent photocatalysis for eliminating tetracycline hydrochloride (TC). When irradiated by simulated sunlight, the 20 %CZS/BOC heterostructure manifests a photocatalytic activity with η(40 min)/kapp = 95 %/0.06825 min−1, which is enhanced by 6.9 (or 1.9) times over that of bare BOC (or Cd0.7Zn0.3S). While exerting ultrasonic vibration during the simulated-sunlight illumination, i.e., for the piezo-photocatalysis, a further improvement in the TC degradation rate is observed. The synergistic factor is calculated to be 1.5, quantifying the enhancement degree achieved by piezo-photocatalysis collaboration. The enhanced piezo-photocatalysis can be interpreted by the accelerated separation of the bulk photoelectrons and photoholes in the photocatalysts resulted from ultrasonic-induced polarization field, thus elevating their utilization for redox reactions. This work could advance the application of piezo-photocatalysts in environmental remediation.

Enhanced tetracycline removal in sequencing batch reactors by bioaugmentation using tetX-carrying strains: Efficiency and mechanisms

Tetracyclines antibiotics (TCs) pose notable environmental challenges due to their persistence in the effluent of wastewater treatment systems. Bioaugmentation offers a promising strategy for their removal, yet information is still very limited. This study aimed to assess the efficacy of bioaugmentation using wild-type (Sphingobacterium sp. WM1) and engineered tetX-carrying (PUC-tetX) strains for enhancing tetracycline (TC) removal in sequencing batch reactors (SBRs). Bioaugmentation mitigated TC's inhibitory effects on denitrification and phosphorus removal processes within SBR systems. Specifically, strain WM1 outperformed strain PUC-tetX in removing TC from sludge and maintained a longer viability. TC addition (500 μg/L, at an environmentally relevant concentration) and bioaugmentation did not significantly impact overall microbial community diversity. Notably, the introduction of these exogenous bacteria markedly increased the abundance of the tetX gene, correlating with the increase in TC degradation. Interestingly, MAGs associated with the Chloroflexi phylum in bioaugmented reactors showed the transfer of the tetX gene to autochthonous bacterial species, promoting TC removal capability. These findings underscored the potential of bioaugmentation to enhance antibiotic removal and provided insights into the dynamics of ARGs and tetX gene within activated sludge systems.

Electrochemistry enhanced multi-stage biological contact oxidation treating sulfamethoxazole wastewater: Performance, degradation pathway and microbial community

Clean and economical techniques are in urgent need for improving antibiotics removal from wastewater. In this study, a multi-stage bio-contact oxidation reactor (BCOR) was constructed and further enhanced by electrochemistry to treat sulfamethoxazole (SMX) wastewater. The stimulatory effects of the electrochemistry were investigated together with the succession of microbial communities as well as the possible conversion pathways of SMX. The results showed that the SMX and chemical oxygen demand removal rates reached up to 92.96 ± 0.62 % and 91.42 ± 0.82 % at electric current density of 2.0 mA/cm2. Electrochemistry enhancement induced bone cleavage and oxidation transformation pathways of SMX while reduced the toxicity of degrading intermediates. Moreover, electrochemistry enhancement stimulated the growth of Klebsiella and Rhodobacter as well as the fermentation, chemoheterotrophy and aerobic_chemoheterotrophy functions which further promoted the SMX removal. This study revealed the biochemical removal mechanisms of SMX degradation and manifested the feasibility of combing electrochemistry with BCOR to treat antibiotics wastewater with low energy consumption.

Dual-defect AgBiO3/DCN S-scheme heterojunction for booted photocatalytic removal of Norfloxacin: Interfacial charge transfer, mechanism and toxicity assessment insights

Antibiotics pollution may pose a great risk to ecosystem and human health. In this work, an innovative dual-defect AgBiO3/DCN S-scheme heterojunction was constructed to overcome the sluggish charge separation and transfer issue and showed exceptional photodegradation performance towards norfloxacin (NFL) pollution under the visible light. The degradation efficiency of NFL reached 95.30 % within 120 min respectively, the rate constant was 3.64 times higher than that of defective g-C3N4 (DCN). The systematically characterizations proved that the enhanced photocatalytic activity was benefited from optimized band structures, improved carrier separation efficiency, due to dual defects and S-scheme heterojunction in AgBiO3/DCN. the intermediate degradation products and degradation pathway of NFL were speculated by UPLC-HRMS, and the environmental toxicity degree of degradation products was analyzed according to the T.E.S.T software. The charge transfer pathway was confirmed as an S-scheme mechanism through a combination of band structure analysis, alongside electron paramagnetic resonance (EPR) experiments.The quenching experiments and ESR analyses indicated that h+ and O2•− radicals played predominant roles. The efficient and stable photocatalytic NFL degradation efficiency and broad environmental adaptability proved potential practical application. This work may shed light on designing new dual-defect heterojunction with photocatalytic antibiotic removal capability in the innovative water treatment process.

Zwitterionic MOF-embedded alginate beads with polydopamine surface functionalization for efficient doxycycline removal: Optimization and mechanistic study

The adsorptive removal of amphoteric antibiotics like doxycycline (DOX) is a difficult task because of the electrostatic repulsion between these amphoteric molecules and adsorbents. For this purpose, a zwitter adsorbent was fabricated by incorporating zwitter ZIF-67/MIL-88A binary MOF into the matrix of alginate (Alg); in addition, the surface of the beads was modified by polydopamine (PDA). The batch experiments implied the super-high adsorption efficacy of ZIF-67/MIL-88A@Alg@PDA toward DOX attained 384.61 ± 5.08 mg/g at a neutral pH medium, 25 °C, and using 0.02 g. The isotherm analysis implied the physisorption of DOX onto ZIF-67/MIL-88A@Alg@PDA, while the kinetic analysis denoted the chemisorption of DOX. The results of XPS, Zeta potential, and Lab experiments identified the types of physical and chemical interactions between ZIF-67/MIL-88A@Alg@PDA and DOX. The durability of the ZIF-67/MIL-88A@Alg@PDA beads was inspected by the recycling test, clarifying that the DOX adsorption aptitude declined by 12.22 mg/g. In addition, the measured leaching concentrations of cobalt and iron from the leaching test were 0.008 and 0.098 mg/L. The ionic strength of ZIF-67/MIL-88A@Alg@PDA, implying an enhancement in the DOX removal (%) from 83.51 to 93.50 % by raising the NaCl concentration from 0.2 to 1.0 mol/L. Therefore, our study could provide a simple procedure to overcome the electrostatic repulsion that retard the adsorption process of the amphoteric drugs onto charged adsorbents with positive or negative charges. Additionally, this procedure could also generate an electrostatic interaction between the zwitter adsorbents and the amphoteric drugs at specific pH media when they are in a zwitterionic nature.

The role of TiO2 and gC3N4 bimetallic catalysts in boosting antibiotic resistance gene removal through photocatalyst assisted peroxone process

Antibiotics are extensively used in human medicine, aquaculture, and animal husbandry, leading to the release of antimicrobial resistance into the environment. This contributes to the rapid spread of antibiotic-resistant genes (ARGs), posing a significant threat to human health and aquatic ecosystems. Conventional wastewater treatment methods often fail to eliminate ARGs, prompting the adoption of advanced oxidation processes (AOPs) to address this growing risk. The study investigates the efficacy of visible light-driven photocatalytic systems utilizing two catalyst types (TiO2-Pd/Cu and g-C3N4-Pd/Cu), with a particular emphasis on their effectiveness in eliminating blaTEM, ermB, qnrS, tetM. intl1, 16 S rDNA and 23 S rDNA through photocatalytic ozonation and peroxone processes. Incorporating O3 into photocatalytic processes significantly enhances target removal efficiency, with the photocatalyst-assisted peroxone process emerging as the most effective AOP. The reemergence of targeted contaminants following treatment highlights the pivotal importance of AOPs and the meticulous selection of catalysts in ensuring sustained treatment efficacy. Furthermore, Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) analysis reveals challenges in eradicating GC-rich bacteria with TiO2 and g-C3N4 processes, while slight differences in Cu/Pd loadings suggest g-C3N4-based ozonation improved antibacterial effectiveness. Terminal Restriction Fragment Length Polymorphism analysis highlights the efficacy of the photocatalyst-assisted peroxone process in treating diverse samples.

Synergistic effects enabled efficient photocatalytic removal of ofloxacin antibiotic in wastewater by layered double hydroxides loaded lignin-derived carbon fibers

The environmental problems caused by the abuse of antibiotics are raising serious attention, and the removal of antibiotics in wastewater is meaningful yet challenging. In this work, lignin-derived carbon fibers loaded layered double hydroxides (LDH@LCF) has been prepared for the removal of ofloxacin (OFX) from wastewater via photocatalysis, which exhibit a high degradation efficiency of 96 % under visible light and maintained 90 % after five reuses. The effects of Zn2+/Fe3+ in the samples and other parameters affecting the photocatalytic efficiency of OFX have been systematically investigated. Results demonstrated that the enhanced photocatalytic efficiency is derived from the synergistic effect of the Zn2+ and Fe3+ in the LDH with a reduced band gap of the catalyst, higher number of oxygen and metal unsaturated coordination sites, and rapid removal of photogenerated electrons. The working mechanism and degradation pathways for OFX by LDH@LCF are also elucidated in detail.

Effective removal of tetracycline antibiotics from water by in-situ nitrogen-doped porous biochar derived from waste antibiotic fermentation residues

This study explored the utilization of waste oxytetracycline fermentation residue (OFR), abundant in nitrogen and organic matter, to prepare in-situ nitrogen-doped porous biochar (activated OFR derived biochar, AOBC) through a coupled pyrolysis process, and investigated the removal of tetracycline antibiotics (TCs) from water with the prepared AOBCs. The physicochemical characterization results showed the characterizations of abundant nitrogen functional groups, high specific surface area (1960.38 m2/g), and the high microporosity (61.6%) for AOBCs. At 25 ℃, the maximum adsorption capacity calculated by Langmuir model of AOBC-3-600 for tetracycline hydrochloride (TC), chlortetracycline hydrochloride (CTC), oxytetracycline hydrochloride (OTC), and doxycycline hydrochloride (DOC) reached 473.00, 293.28, 220.61, and 282.72mg/g, respectively. The superior fit of the pseudo-second-order and Langmuir models indicated that the adsorption mechanism involved both the physical effect (pore filling) and chemical interactions (electrostatic attraction, hydrogen bonding, π-π interaction, and Lewis acid-base interaction). Environmental risk assessments substantiated the absence of residual oxytetracycline and antibiotic resistance genes in the prepared biochar, indicating its application safety. This research provides a sustainable route to simultaneously treat the antibiotic contamination in water and rationally utilize antibiotic fermentation residues.

Interactions between antibiotic removal, water matrix characteristics and layered double hydroxide sorbent material

Sorption by layered double hydroxides (LDH) is gaining substantial interest for remediating emerging contaminants, including pharmaceuticals from wastewaters. Findings from a sorbent material performing successfully in lab-based studies using non-environmental (laboratory-sourced) water cannot be assumed to translate to equal performance under environmental downstream applications. However, studies evaluating sorbent material performance for removal of pollutants and understanding material interactions with environmental waters are limited. This study evaluates the removal of the antibiotic amoxicillin (AMX) using a Mg2Al–NO3-LDH sorbent material from laboratory-grade water and wastewater effluent (WWE). AMX is successfully removed (94.53 ± 4.30 % within 24 h) in laboratory-grade water (under batch sorption conditions: 100 μg/L AMX, 0.2 g/L LDH, 20 °C). The comparison of LDH removal performance in laboratory grade and WWE shows a decreased maximum removal of AMX in WWE (13.39 ± 5.53 %). A lower final AMX concentration is observed in the WWE without the presence of LDH, compared to the ‘removal’ experiments in WWE with the presence of LDH, indicating a contribution of non-sorption removal pathways of AMX. This is proposed to be due to the difference in metal concentrations in the WWE with and without LDH present. The presence of LDH is found to decrease concentrations of metal pollutants in WWE, such as Zn concentration decreasing by 85 % over 24 h, changing water characteristics. Overall, this paper reports that an LDH performs differently in laboratory-sourced water and a wastewater effluent. This provides evidence that sorbent material performance needs to be evaluated in complex water matrices to ensure that it is representative of how a sorbent material will perform in an environmental application, which is the end goal of developing such technologies. Finally, good practice recommendations are provided for future lab-scale sorption experiments evaluating the performance of any new sorbent materials for water treatment applications.

Effects of hydrothermal pretreatment on sulfadiazine degradation during two-stage anaerobic digestion of pig manure

Antibiotics in animal manure pose significant risks to the environment and health. While anaerobic digestion (AD) is commonly used for pig manure treatment, its efficiency in antibiotic removal has been considerably limited. This study investigated the impact of hydrothermal pretreatment (HTP) on sulfadiazine (SDZ) removal in a two-stage AD system. Results indicated that the HTP process reduced SDZ concentration by 40.61%. Furthermore, the SDZ removal efficiency of the AD system coupling HTP increased from 50.90% to 65.04% compared to the untreated system. Biogas yield was also improved by 26.17% while maintaining system stability. Changes induced by HTP in the microbial communities revealed that Firmicutes, Bacteroidetes, Caldatribacteriota, and Proteobacteria emerged as the primary bacterial phyla. Following HTP, the relative abundance of Prevotella, which exhibited a strong negative correlation with SDZ concentration, increased significantly by 25-fold in the acidogenic stage. Proteiniphilum, Syntrophomonas and Sedimentibacter showed notable increases in the methanogenic stage after HTP. The N-heterocyclic metabolism carried out by Prevotella might have been the predominant SDZ degradation pathway in the acidogenic stage, while the benzene ring metabolism and hydroxylation by the Proteiniphilum emerged as the primary degradation pathways in the methanogenic stages. Furthermore, biodegradation intermediates were proven to be less toxic than SDZ itself, indicating that the HTP-enhanced two-stage AD process could be a viable way to lower the environmental risks associated with SDZ. The findings from this study provide valuable insights for removing SDZ from the environment via two-stage AD.

CO2(OH)2CO3 and Fe doped Co2(OH)2CO3 prepared as efficient and stable catalysts for activation of PMS: Two systems comparison and key role of high-valent metal-oxo species in mechanism revealing

High-valent metal-oxo species [M(IV) = O] exhibited high selectivity and chemical efficiency in advanced oxidation processes for removing organic pollutants, making their manipulation essential in catalytic systems. However, the low and unsustainable efficiency of generating M(IV) = O posed significant challenges. In this research, Co2(OH)2CO3 were successfully prepared via a one-pot hydrothermal method to efficiently activate peroxymonosulfate (PMS) with high-valent cobalt-oxo species [Co (IV) = O] as the primary active oxidation species. Building upon this foundation, COC was modified through variations in metal types and elemental ratios, in which magnetically enriched FexCo2-x(OH)2CO3 was synthesized by gradient Fe doping with higher catalytic efficiency and stability. The insertion of Fe resulted in the lengthening of the Co-O bond and improved the valence distribution of cobalt on the COC surface. Besides, it enabled part of the electrons to be transferred from the Fe active center to the Co active center, breaking the limitation of the traditional two-electron transfer and realizing the stable generation of more high-valent metals. Both reaction systems achieved efficient degradation of sulfadimethoxine (SDM) within 30 min and were able to completely degrade SDM within 30 min even after three cycles. FexCo2-x(OH)2CO3 maintained excellent catalytic performance even after 30 days of exposure to air. In both systems, high-valence metals played a dominant role, while the contributions of hydroxyl radicals and sulfate radicals were negligible. Overall, the two groups of developed catalysts both showed remarkable stability and pollutant removal performance in anions, humic acid, Different antibiotics and real water systems, which provided a new perspective on antibiotic removal.