Efficient Removal Of Antibiotics Research Articles

A novel metal-free perylene-functionalized graphite adsorbent for efficient antibiotic removal from wastewater.

Adsorption remains a widely utilized and effective technique for removing chemical contaminants from polluted water, and novel adsorbents are currently in the process of being developed. The presence of antibiotics residues in aqueous effluents is a potential concern due to their potential adverse effects on living organisms. In this work, perylene tetracarboxylic acid-functionalized expanded graphite (PTCA-EG) was synthesized as a metal-free adsorbent and its potential for efficient treatment of contaminated wastewater with cefalexin (CLX) antibiotic was studied. The experimental variables were modeled and optimized using central composite design (CCD) and response surface methodology (RSM) to maximize adsorption efficiency. In this regard, the contact time of 20min, solution pH of 7.0, adsorbent dosage of 18mg, and initial CLX concentration of 45mg L-1 were found to be the optimum conditions for adsorptive removal of CLX with a maximum efficiency of 99 ± 1.21%. In addition, the adsorption equilibrium data were well analyzed with isotherm, kinetic, and thermodynamic studies. The isotherm results revealed the adsorption process was favorable and took place on the heterogeneous surface. Moreover, the Langmuir maximum adsorption capacity (Qmax) was determined as 220.7mgg-1. Also, thermodynamic parameters revealed the spontaneity and endothermic nature of the adsorption process. The reusability studies demonstrated that the spent PTCA-EG can be easily regenerated through NaOH solution (0.01mol L-1) and reused for six cycles without any significant decrease in its adsorption efficiency. Also, the PTCA-EG showed excellent behavior in adsorptive removal of CLX in real water samples including river water (96.61 ± 1.82%) and hospital effluents (91.91 ± 3.41-93.69 ± 3.06%).

Efficient Removal of Antibiotics From Water via a Novel Magnetic Hypercrosslinked Polymer

ABSTRACTThe removal of antibiotic residues from environmental media is a significant challenge in the field of chemistry. In this work, we presented a simple and efficient method for eliminating tetracycline hydrochloride (TC) and chloramphenicol (CAP) from water. Initially, 1,4‐dichlorobenzene and ferrocene were employed as starting materials for the synthesis of hypercrosslinked polymers (HFDs) via Friedel–Crafts alkylation facilitated by a cross‐linking agent. Subsequent to this, an efficient magnetic adsorbent material (MHFD) was developed by the in situ oxidation of the iron source incorporated within the polymer matrix of HFDs. The resulting MHFDs demonstrated an impressive maximum Brunauer–Emmett–Teller (BET)–specific surface area of 1190 m2/g and exhibited a peak saturation magnetization of 11.8 emu/g. This work investigated the effects of four factors on the adsorption performance of MHFD‐10, including contact time, solution pH, dosage of MHFD‐10, and initial antibiotic concentration. The results revealed a remarkable conformity of the adsorption kinetics with the pseudo‐second‐order model and the adsorption isotherms with the Langmuir model. Thermodynamic analysis revealed that the adsorption process is spontaneous and exothermic. Specifically, at a temperature of 20°C, MHFD‐10 achieved maximum adsorption capacities of 193.95 mg/g for CAP and 268.60 mg/g for TC. Furthermore, these materials exhibited exceptional reusability, maintaining high adsorption capacities even after undergoing five consecutive reuse cycles.

Exploring the Mechanism for the Photocatalytic Degradation of Oxytetracycline in Water using TiO2 and Supplementary Oxidants

The persistent presence of antibiotics in wastewater, exemplified by oxytetracycline (OTC), poses environmental risks, necessitating robust removal strategies. This study investigates the effectiveness of photocatalysis utilizing TiO2 (P25) treated at various temperatures, combined with different oxidants such as hydrogen peroxide (H2O2), potassium peroxydisulfate (PDS), potassium peroxomonosulfate (PMS) under diverse experimental conditions. The research systematically explores the impact of temperature, pH, and oxidant concentration on the efficiency of OTC degradation. Our findings reveal that the combination of P25/500, PDS, UV irradiation, and stirring demonstrates superior OTC degradation, surpassing 99% efficiency after 180 min. Optimal pH conditions are identified, emphasizing the importance of balancing acidity for enhanced performance. The study also provides insights into the optimal PDS concentration, indicating a threshold beyond which further increases yield diminishing returns. Mechanistic understanding is enhanced through scavenger experiments, elucidating the pivotal role of reactive oxygen species, particularly O2•−, in the photocatalytic process. This research offers a practical framework for TiO2-based photocatalysis in wastewater treatment, emphasizing tailored conditions for efficient antibiotic removal. The outcomes contribute valuable insights to the development of sustainable wastewater treatment protocols targeting antibiotic pollutants.

Construction of Co-Modified MXene/PES Catalytic Membrane for Effective Separation and Degradation of Tetracycline Antibiotics in Aqueous Solutions.

The application of antibiotics has advanced modern medicine significantly. However, the abuse and discharge of antibiotics have led to substantial antibiotic residues in water, posing great harm to natural organisms and humans. To address the problem of antibiotic degradation, this study developed a novel catalytic membrane by depositing Co catalysts onto MXene nanosheets and fabricating the polyethersulfone composite (Co@MXene/PES) using vacuum-assisted self-assembly. The dual role of MXene as both a carrier for Co atoms and an enhancer of interlayer spacing led to improved flux and catalytic degradation capabilities of the membrane. Experimental results confirmed that the Co@MXene/PES membrane effectively degraded antibiotics through peroxymonosulfate activation, achieving up to 95.51% degradation at a cobalt concentration of 0.01 mg/mL. The membrane demonstrated excellent antibacterial properties, minimal flux loss after repeated use, and robust anti-fouling performance, making it a promising solution for efficient antibiotic removal and stable water treatment.

Spin-dependent activity of cobalt contained hydroxy double perovskite for efficient antibiotic removal via peroxymonosulfate activation

Cobalt-containing catalysts exhibit good performance in the advancement of efficient catalytic oxidation reactions. However, achieving an optimal balance between reaction kinetics and reactant adsorption that is governed by the spin states of Co ions remains a significant challenge. This study aims to develop a convenient compositional tuning strategy to achieve such balance in stable CoxZn1-xSn(OH)6 perovskite hydroxides. The effect of varying spin state on peroxymonosulfate activation and tetracycline hydrochloride removal is systematically investigated. The magnetic properties analysis reveals that the content of high-spin Co2+ ions in octahedral site increases with Co content (x) and reaches 59.5 % in Co0.5Zn0.5Sn(OH)6. Experimental results and DFT calculations reveal that the spin state transition of Co2+ ions enhances the interaction between Co and O atoms. This enhanced interaction not only improves the reactivity due to the formation of highly covalent Co-OH bonds that serve as catalytically activated charge transfer channels, but also optimizes the suitable adsorption energy of PMS molecules at −3.52 eV for Co0.5Zn0.5Sn(OH)6. Consequently, Co0.5Zn0.5Sn(OH)6 shows superior catalytic activity, achieving nearly 100 % antibiotic removal efficiency within just 10 min, surpassing previously reported catalysts. These findings underscore the potential of compositional tuning spin states of transition metal ions in advancing oxidation processes and designing innovative catalysts.

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.

Construction of Ti3C2/BiOBr heterojunction for efficient removal of antibiotics

Construction of Ti3C2/BiOBr heterojunction for efficient removal of antibiotics

Self-supporting three-dimensional CuNi–Sb–SnO2 anode with ultra-long service life for efficient removal of antibiotics in wastewater

Electrochemical ozone production (EOP) is a promising technology for the removal of contaminants in wastewater. However, traditional two-dimensional anodes for EOP are restricted by their reliance on substrates and limited surface area, thus exhibiting poor stability and efficiency. Herein, a novel three-dimensional Sb–SnO2 with Cu and Ni co-doped (3D CuNi-ATO) was synthesized via a facile pressing-sintering method without the Ti substrate. 3D CuNi-ATO had a specific surface area two orders of magnitude higher than conventional CuNi-ATO/Ti, as well as the significant capability of EOP that differs from intrinsic 3D ATO. This endowed 3D CuNi-ATO with the capability to remove tetracycline with a pseudo-first-order rate constant of 0.033 min−1 under a low current density of 5 mA cm−2 within 120 min, which was far more efficient than that by 3D ATO and other two-dimensional anodes reported. The 3D CuNi-ATO was confirmed stable in 100 cycles and had an accelerated service lifetime of over 1100 h versus 83 h of CuNi-ATO/Ti. The degradation of tetracycline in complex matrix and flow-through reactors further revealed the promising potential of 3D CuNi-ATO to be applied in scenarios of practical application and continuous high-rate treatment.

Bifunctional 0D carbon quantum dot cathode electrocatalyst coupled with atomic hydrogen and hydroxyl radicals for efficient removal of oxytetracycline hydrochloride

Efficient removal of antibiotics is difficult to achieve by conventional single-oxidation or reduction processes. Herein, a bifunctional cathodic electrocatalyst coupling atomic hydrogen (H*) reduction with hydroxyl radical (·OH) oxidation in an efficient electrocatalytic process was developed for the effective degradation of oxytetracycline hydrochloride (OTC). Pd particles were dispersed on B-doped carbon quantum dots to prepare a Pd-B-doped carbon quantum dots/titanium (Pd-BCQD/Ti) electrode as a bifunctional cathode catalyst. The electrode can simultaneously generate H* through the H2O/H+ reduction process, H2O2 through the oxygen reduction process, and then generate ·OH. H* performs nucleophilic hydrogenation reduction of OTC molecules, and ·OH performs electrophilic oxidation of the carbon skeleton, and both act synergistically with the active chlorine species (HClO) generated at the anode. The experimental results showed that the electrode achieved 90.50 % removal of OTC within 60 min. In addition, the Pd-BCQD/Ti electrode reduces energy consumption while increasing current efficiency. The degradation effect was more than 85.80 % in the pH range of 3∼9, indicating fairly stable catalytic activity over a wide pH range. The degradation efficiency was basically unchanged after ten cycles, and the reactivity was still high in the actual water. Intermediates were analyzed based on LC-MS to explore the degradation pathways of OTC. The toxicity of the intermediates generated during OTC degradation was predicted based on quantitative conformational relationships. This study provides a feasible strategy for the preparation of bifunctional catalysts based on zero-dimensional BCQD for efficient green antibiotic wastewater treatment.

Efficient removal of antibiotics from wastewater by chitosan/polyethyleneimine/Ti3C2 MXene composite hydrogels: Synthesis, adsorption, kinetics and mechanisms

A novel chitosan-based composite hydrogel (CS/PEI-MXene) made of polyethyleneimine and Ti3C2 MXene as modifiers and acrolein as crosslinker has been synthesized simply and conveniently, which could be applied in the removal of residual antibiotic pharmaceuticals (chlortetracycline (CTC), ibuprofen (IBU), etc.) from aqueous environments. The CS/PEI-MXene was used as an adsorbent for chlortetracycline and ibuprofen. The removal rates of CTC and IBU could be achieved to 91.1 % and 99.25 %, respectively. In addition, the reusability of CS/PEI-MXene for CTC and IBU appeared good capacity, and the removal rate was maintained at approximately 70 % after five cycles. FT-IR, XPS, and zeta potential were used to show that the hydrogel was successfully synthesized, and its physicochemical characteristics were studied. Systematically examined were conducted on the effects of pH (3−10), contact time (0–120 min), and temperature (30–40 °C) on the adsorption efficiency of CS/PEI-MXene. The adsorption mechanism of CS/PEI-MXene on CTC and IBU mainly included electrostatic interactions and hydrogen bonding. Overall, the development of MXene based hydrogel adsorbent will provide a practical approach to the treatment of wastewater containing antibiotic pharmaceuticals and have great potential for practical applications.

Antibiotic Removal by Three Promising Microalgae Strains: Biotic, Abiotic Routes, and Response Mechanisms

Microalgae represent an alternative to conventional wastewater treatment, potentially improving antibiotic removal and offering a solution to combat the spread of antimicrobial resistance. Through batch assays, this study investigates the routes for antibiotic removal using three strains (Chlamydomonas acidophila, Auxhenochlorella protothecoides and Tetradesmus obliquus). Using mixtures of ciprofloxacin, clarithromycin, erythromycin, metronidazole, ofloxacin, sulfamethoxazole, and trimethoprim at concentrations simulating wastewater composition, it also assesses antibiotic effects on microalgae physiology. The three strains primarily removed antibiotics through rapid biosorption, achieving up to 91.5% removal for specific ones like ciprofloxacin. T. obliquus and C. acidophila showed efficacy, with total removals of 37.2% and 49.3%, respectively. Over time, A. protothecoides demonstrated the highest active removal efficiency, eliminating 22.1% of total antibiotics, with a notable 67.6% removal for sulfamethoxazole. Abiotic degradation through hydrolysis and photolysis contributed to ciprofloxacin, ofloxacin, clarithromycin, and erythromycin removal (34.7% to 96.7%), showing pH-dependent photolysis. However, algae induced a shading effect, reducing the photolytic and hydrolytic degradation of specific antibiotics. T. obliquus and C. acidophila were inhibited by antibiotics, whereas A. protothecoides showed a 30.6% growth rate increase. The stimulatory effect was also observed for the nutrient removal, with A. protothecoides showing a 46.6% increase in ammonium removal and a 44.8% increase in phosphate removal with antibiotics. Additionally, antioxidant activities remained stable, except for a notable increase in peroxidase activity for A. protothecoides and T. obliquus. The study confirms efficient antibiotic removal and stimulatory responses in the three algal strains, indicating their potential for wastewater treatment and combating antimicrobial resistance.

Synergy of oxygen reduction for H2O2 production and electro-fenton induced by atomic hydrogen over a bifunctional cathode towards water purification

In the Electro-Fenton (EF) process, hydrogen peroxide (H2O2) is produced in situ by a two-electron oxygen reduction reaction (2e ORR), which is further activated by electrocatalysts to generate reactive oxygen specieces (ROS). However, the selectivity of 2e transfer from catalysts to O2 is still unsatisfactory, resulting in the insufficient H2O2 availability. Carbon based materials with abundant oxygen-containing functional groups have been used as excellent 2e ORR electrocatalysts, and atomic hydrogen (H*) can quickly transfer one electron to H2O2 in a wide pH range and avoiding the restrict of traditional Fenton reaction. Herein, nickel nanoparticles growth on oxidized carbon deposited on modified carbon felt (Ni/Co@CFAO) was prepared as a bifunctional catalytic electrode coupling 2e ORR to form H2O2 with H* reducing H2O2 to produce ROS for highly efficient degradation of antibiotics. Electrochemical oxidation and thermal treatment were used to modulate the structure of carbon substrates for increasing the electro-generation of H2O2, while H* was produced over Ni sites through H2O/H+ reduction constructing an in-situ EF system. The experimental results indicated that 2e ORR and H* induced EF processes could promote each other mutually. The optimized Ni/Co@CFAO with a Ni:C mass ratio of 1:9 exhibited a high 2e selectivity and H2O2 yield of 49 mg L−1. As a result, the designed Ni/Co@CFAO exhibited excellent electrocatalytic ability to degrade tetracycline (TC) under different aqueous environmental conditions, and achieved 98.5% TC removal efficiency within 60 min H2O2 and H* were generated simultaneously at the bifunctional cathode and react to form strong oxidizing free radicals •OH. At the same time, O2 gained an electron to form •O2−, which could react with •OH and H2O to form 1O2, which had relatively long life (10−6∼10−3 s), further promoting the efficient removal of antibiotics in water.

MAPPING CHITOSAN POTENTIALS FOR TREATING ANTIBIOTICS IN AQUACULTURE WASTEWATER

The potential of chitosan-based materials for the remediation of antibiotics in aquaculture wastewater is evaluated, emphasizing emerging pollutants and the mechanisms underlying their adsorption processes. The efficiency of chitosan nano-composites and their modifications in adsorbing antibiotics, such as tetracycline, is scrutinized, providing insights into deprotonation, protonation, and the impact of concentration on surface interactions. Chemical modifications enhancing adsorption efficiency and the synergistic removal of antibiotics and metal ions using advanced materials like magnetic core-brush composites and cross-linked electrospun chitosan nanofibers are highlighted. The discourse extends to the challenges and recent advancements in removing a spectrum of antibiotics, including tetracycline, amoxicillin, erythromycin, norfloxacin, chloramphenicol, ciprofloxacin, and sulfanilamide. Various adsorbents, such as chitosan nanocomposites, hydrogels, membranes, fibres and nanofibers, foam and sponges, are examined alongside molecularly imprinted chitosan for selective adsorption. The optimization of adsorption processes with chitosan-metal microspheres, and the pivotal role of pH-dependent mechanisms and chemisorptive processes, are also explored. In summary, chitosan-based materials demonstrate substantial promise for the efficient removal of antibiotics from aquaculture wastewater, with ongoing research dedicated to optimizing adsorption capacities.

Magnetic composite photocatalyst NiFe₂O₄/ZnIn₂S₄/biochar for efficient removal of antibiotics in water under visible light: Performance, mechanism and pathway

The widespread presence of antibiotics in aquatic environments, resulting from excessive use and accumulation, has raised significant concerns. A NiFe₂O₄/ZnIn₂S₄/Biochar (NFO/ZIS/BC) magnetic nanocomposite was successfully synthesized, demonstrating significantly enhanced electron-hole separation properties. Comprehensive investigations were conducted to evaluate the impact of various parameters, including catalyst mass, pH, and the presence of co-existing ions on the composite's performance. The nanoparticles of NiFe₂O₄ (NFO) and ZnIn₂S₄ (ZIS) were found to improve the surface stability and sulfamethoxazole removal capabilities of porous biochar, while also demonstrating high total organic carbon removal efficiencies. •O₂⁻ and h⁺ were identified as the predominant reactive oxygen species (ROS) in NFO/ZIS/BC-4 during the degradation process. The degradation outcomes of sulfamethoxazole under natural sunlight and water conditions were consistent with laboratory findings, affirming the robust applicative potential of NFO/ZIS/BC. Density functional theory (DFT) calculations were performed to elucidate the photocatalytic mechanism and identify potential intermediate products. Additionally, the types of heterojunctions present in the system were characterized and discussed. After multiple iterations, NFO/ZIS/BC-4 maintained effective photodegradation capabilities through five cycles. This study presents an effective method for the treatment of antibiotics in aquatic environments, offering significant potential for environmental applications.

A review on utilization potential of functionalized biochar for the removal of antibiotics from water

Globally, water resources are facing serious threat owing to the increasing concentration of various emerging contaminants. Indiscriminately discarded and/or excreted antibiotics and their residues are one such emerging contaminants. Since long-term persistence of these residues in environment is responsible for developing antimicrobial (antibacterial) resistance in the organisms, their removal from water / wastewater is essential. Hence, scientists are attempting to evolve novel methods to encounter antibiotics and their residues in water. One such method is the adsorption of antibiotics onto a suitable matrix thereby reducing their concentration in water. Biochar has been proven to act as a suitable adsorbent for various contaminants; however, their removal efficiency remains a concern. Therefore, functionalization of biochar using various physical and chemical modifications, was developed as a technique that can help in efficient removal of antibiotics. Functionalization has been seen to improve the physical and chemical properties of biochar; such as, pore volume, pore diameter, surface morphology, surface functional groups, polarity, porosity etc. In this review, functionalized biochars have been explored to understand their efficacy and mechanism for the removal of antibiotics and their residues. The discussion includes biochar functionalization methods, impact of property modifications on the removal of antibiotic residues, and their removal mechanism. In addition, cost-effectiveness, economy of the adsorption process, and its environmental effects have also been dealt with.

Tourmaline/pyrite dual mineral photocatalysis with a powerful surface electric field for efficient antibiotic removal

Pyrite (FeS2) has garnered attention due to its narrow bandgap, high light absorption, and low cost. However, the rapid recombination of charge carriers hinders its practical application. Surface electric field is a unique characteristic of tourmaline, which can induce effective separation of photo generated electrons and holes. This study successfully combined two directly mined natural minerals, tourmaline and pyrite, to form TFS. Characterization and experiments show that the surface electric field of tourmaline can significantly enhance the photocatalytic activity of TFS. Tetracycline (TC, 50 ppm) was degraded by 95% with 60 min, and the TFS reaction rate constant reached 0.0439 min−1, which is 6.1 times and 17.3 times higher than that of tourmaline and FeS2. Additionally, it significantly improved light absorption and charge carrier separation capabilities. After simulating various natural environmental factors, TFS demonstrated practicality. Considered analysis of active substances and detection revealed that h+ and 1O2 radicals are significant contributors, and the photocatalytic mechanism was proposed. Furthermore, the transformation pathways and toxicity of metabolites were studied. This research offers further inspiration and insights for improving photocatalytic material performance and the green governance environment of natural resources.

A metal-free Z-scheme PPy/MCN heterojunction for antibiotic removal via synergism of photocatalysis and peroxymonosulfate activation

Developing an active and synergistic system based on photocatalysis and peroxymonosulfate (PMS) activation is considered an effective strategy for efficient removal of antibiotics. However, photocatalytic heterojunctions generally comprise metallic catalysts that can cause metal leaching and secondary pollution, and a clear understanding of the synergy between photocatalysis and PMS activation is still missing. Herein, a metal-free Z-scheme polypyrrole (PPy)/melamine-derived graphitic carbon nitride (MCN) heterojunction photocatalyst was synthesized via calcination and in-situ loading for catalyzing the degradation of ciprofloxacin (CIP) and other emerging pollutants in a visible light-emitting diode (LED)/PMS synergistic system, which showed a significantly higher activity than the single LED and PMS systems. The optimal 0.5 %PPy/MCN (0.5 % is the mass ratio of PPy in the mixture of PPy/MCN) performed well under a wide pH range (3–11), while exhibiting superior anti-interference for common water constituents and outstanding reusability and stability. The 0.5 %PPy/MCN/LED/PMS synergistic system showed the highest kinetic constant (0.0643 1/min), which increased 3.00, 6.77 and 2.91-fold over the 0.5 %PPy/MCN/PMS, 0.5 %PPy/MCN/LED, and MCN/LED/PMS system, respectively. Mechanistic investigation and theoretical calculations revealed that PPy, with its high conductivity and strong light absorption ability, facilitated the generation and separation of e−/h+ in the 0.5 %PPy/MCN/LED/PMS system and activated PMS for generating reactive species such as 1O2, which degraded cCIP together with h+. Furthermore, electron transfer pathway (ETP) was elucidated using electrochemical characterizations. CIP was degraded via ring opening, cleavage hydroxylation, ammonia oxidation and elimination reactions, which substantially reduced the toxicity of CIP. Overall, this study may help the rational design of metal-free catalysts and provide a deep insight for the LED/PMS synergistic mechanisms.

Multi-interface interaction mechanism of pulp reject-based flocculants for the removal of antibiotics and its combined pollutants

The efficient removal of antibiotics and its combined pollutants is essential for aquatic environment and human health. In this study, a lignin-based organic flocculant named PRL-VAc-DMC was synthesized using pulp reject as the raw material, with vinyl acetate (VAc) and methacryloxyethyltrimethyl ammonium chloride (DMC) as the grafting monomers. A series of modern characterization methods were used to confirm the successful preparation of PRL-VAc-DMC and elucidate its polymerization mechanism. It was found that the Ph-OH group and its contiguous carbon atoms of lignin served as the primary active sites to react with grafting monomers. Flocculation experiments revealed that PRL-VAc-DMC could react with tetracycline (TC) through π-π* interaction, hydrophobic interaction, hydrogen bonding, and electrostatic attraction. With the coexistence of humic acid (HA) and Kaolin, the aromatic ring, hydroxyl, and amide group of TC could react with the benzene ring, hydroxyl group, and carboxyl group of HA, forming TC@HA@Kaolin complexes with Kaolin particles acting as the hydrophilic shell. The increase in particle size, electronegativity, and hydrophily of TC@HA@Kaolin complexes facilitated their interaction with PRL-VAc-DMC through strong interfacial interactions. Consequently, the presence of HA and Kaolin promoted the removal of TC. The synergistic removal mechanism of TC, HA, and Kaolin by PRL-VAc-DMC was systematically analyzed from the perspective of muti-interface interactions. This paper is of great significance for the comprehensive utilization of pulp reject and provides new insights into the flocculation mechanism at the molecular scale.

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.

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.