Ciprofloxacin Adsorption Capacity Research Articles

Study on the adsorption mechanism of ciprofloxacin in wastewater by modified fly ash under the coexistence of copper

The recontamination of farming wastewater with antibiotics and metal ions has emerged as a considerable concern in recent years. In this study, fly ash (FA) served as the adsorbent material, and its modified form (AFA) was developed via response surface optimization. The study involved an analysis of the structure and chemical composition of the fly ash before and after modification, both pre- and post-modification, through the use of scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) analyses. These analyses were aimed at exploring the adsorption mechanism of ciprofloxacin (CIP) in the presence of copper ion (Cu2+) in livestock and poultry wastewater. The study indicates that the optimal modification parameters for AFA include an alkali-to-ash ratio of 1.5, a calcination temperature of 400 °C, and a 3-hour calcination period. At pH 6, AFA exhibited a markedly superior adsorption capacity for CIP in comparison to FA, with AFA achieving 19.32 mg/g and FA only 9.61 mg/g. The adsorption process conforms to the quasi-second-order kinetic model and Langmuir isothermal model.The adsorption capacity for CIP increases at low concentrations, specifically when Cu2+ levels are below 100 mg/L. Nevertheless, elevated CIP concentrations impede the adsorption process. The adsorption of AFA for CIP is observed to decrease with rising temperature, in contrast to the adsorption of Cu2+, which increases as the temperature rises. The adsorption mechanism of AFA is primarily comprised of pore filling, ion exchange, electrostatic interaction, π bond coordination, complexation, and other similar processes.

Effect of environmental factors on adsorption of ciprofloxacin from wastewater by microwave alkali modified fly ash

Antibiotics, as emerging persistent pollutants, pose significant threats to human health. The effective and low-cost removal of ciprofloxacin (CIP) from wastewater has become an important research focus. In this study, fly ash (FA) was used as the raw material, and modified fly ash (MFA) was prepared by varying microwave power, alkali concentration, and immersion time to investigate its adsorption characteristics for CIP. Results showed that the optimal preparation conditions for MFA with the most effective adsorption of CIP, using the Box-Behnken response surface methodology, were a microwave power of 480 W, an alkali concentration of 1.5 mol/L, and a modification time of 3 h. Scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction analyses revealed that after modification, the glassy structure of FA is destroyed, the specific surface area is increased, and obvious hydroxyl O–H absorption peaks appear. Both FA and MFA exhibited adsorption processes for CIP that conformed to pseudo-second-order kinetics and the Langmuir equation. Maximum adsorption of CIP (9.61 and 12.67 mg/g) was achieved at pH = 6. With increasing temperature, the adsorption capacity of both FA and MFA for CIP decreased, indicating an exothermic process. The adsorption capacity of CIP decreased with increasing ion concentration, with the impact order of ions being Al3+ > Ca2+ > Na+. The results show that pore filling, electrostatic interaction, ion exchange and complexation are the main ways of CIP adsorption by FA. Microwave alkali modified fly ash is an economical and efficient adsorbent for CIP removal in water, realizing the purpose of “treating waste with waste”. This study provides a scientific basis for controlling CIP treatment in wastewater.

High-carbon-content biochar from chemical manufacturing plant sludge for effective removal of ciprofloxacin from aqueous media

Biochar is considered a promising biosorbent for harmful organic pollutants in aqueous media. However, only a limited number of biochars derived from industrial sludges have been utilized due to their problematic high ash content and heavy metal leaching. In this study, a highly effective biochar was prepared as a superabsorbent for ciprofloxacin (CIP) from chemical manufacturing plant sludge via K2CO3-activated pyrolysis, and its CIP removal behavior was evaluated. Unlike sewage sludge, chemical manufacturing plant sludge contains low SiO2, resulting in an ultra-pure carbon (95.4%) based biochar with almost negligible ash content. As the pyrolysis temperature increased from 400 to 800 °C, the ordered graphitic carbon structure transformed into an amorphous carbon phase, and most oxygen-containing groups disappeared. However, the pore size significantly decreased to ∼4.5 nm due to the corrosive carbon volatilization caused by K2CO3, resulting in an extremely large surface area of 2331.8 m2/g. Based on its large surface area and porous carbon structure, the activated biochar at 800 °C (CAB-800) exhibited an outstanding CIP adsorption capacity of 555.56 mg/g. The CIP adsorption isotherm, kinetic, and thermodynamic studies were systematically investigated. The CIP adsorption on CAB-800 was mainly attributed to π-π interactions and hydrogen bond formation, with electrostatic interactions partially contributing to the adsorption reaction. From pH 2 to 12, CAB-800 showed an excellent CIP adsorption capacity of over 316.7 mg/g, with adsorption favored under acidic conditions. Except for HCO3− and CO32−, the presence of anions and humic acids did not significantly affect CIP adsorption capacity. These results demonstrate that biochar produced from chemical manufacturing industry sludge via K2CO3 activation is a highly feasible material for the removal of CIP from aqueous media.

Enhanced adsorption of ciprofloxacin from an aqueous solution using a novel CaMgAl-layered double hydroxide/red mud composite

This work reports on CaMgAl-layered double hydroxide (LDH) based red mud (RM) composite prepared via a co-precipitation method, characterized by transmission electron microscopy (TEM), powder X-ray diffraction patterns (XRD), field-emission scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Brunauer-Emmett-Teller analysis (BET), and Fourier transform infrared spectra (FTIR) and subsequently used for elimination of ciprofloxacin (CIP) from an aqueous solution in batch mode experiments. Langmuir isotherm model provided a better fit of CIP adsorption onto CaMgAl/RM composites than a Freundlich isotherm model; indicating a monolayer adsorption phenomena. Pseudo-second-order kinetic models describe the kinetics of adsorption while the adsorption mechanisms were controlled by external mass transfer and intra-particle diffusion. Thermodynamic analysis indicated that the CIP adsorption onto CaMgAl-LDH/RM was exothermic and spontaneous in nature. The prepared adsorbent exhibited superior affinity towards CIP adsorption which yielded a maximum CIP adsorption capacity of up to 138 mg/g. The higher removal efficiency (89.45 %) was reached under the best conditions (pH 7, agitation speed 150 rpm, adsorbent dosage 0.5 g/100 ml, concentration of contaminant 70 ppm, and 90 min contact time). Moreover, the synthesized adsorbent can be recovered after six consecutive regeneration cycles with a minimal reduction in the adsorption ability of 31 %. In conclusion, this study demonstrated that the CaMgAl-LDH/RM composite could be a promising adsorbent for removing antibiotics from wastewater.

Uncovering fabrication approach impact on photocatalytic ciprofloxacin (CIP) antibiotic degradation of brookite TiO2

Solar-driven antibiotic degradation by semiconductor photocatalysis technique offers a promising route to tackle with the environmental issue we are currently facing. Herein, three kinds of brookite TiO2, TiO2-Glycerol (GL)/NaOH (OH−), TiO2-Ethylene glycol (EG)/Ethylenediamine (EDA), and TiO2- Ethylene glycol (EG)/NaOH (OH−), are prepared by changing fabrication approaches from as-prepared two different Ti-polyol precursors. The composition and structure of the above brookite nanocrystals is studied in detail, and the effects of different synthesis methods on their optical properties, surface areas and wettability, and photocatalytic degradation activities are discussed. The photocatalytic ciprofloxacin (CIP) remediation evaluation shows that the TiO2-EG/EDA enriched amine group confirmed by FTIR and XPS measurements has the highest dark adsorption as well as subsequent photocatalytic degradation activities compare with the other two types of brookite. Subsequently, the unveiling on how the TiO2-EG/EDA effectively degrades the CIP molecules is achieved. Indeed, on the basis of a series of characterizations, the good CIP adsorption capacity resulted from the weakest hydrophilicity, the largest specific surface area, the unique chemisorption effect by surface amine group, combining with the smallest band gap, the fastest photogenerated charge transport speed, the longest photogenerated electron lifetime and the most active sites, contribute to the rapid degradation of CIP upon the TiO2-EG/EDA. In addition, the CIP degradation pathway is proposed by HRMS analysis, and the EPI suite program predicts the intermediate molecules have no biotoxicity for the environment. It is expected this work could provide useful reference for highly-efficient photocatalytic antibiotics-degradation in terms of experimental design and materials fabrication.

Preparation of mesoporous biogas residue biochar via a self-template strategy for efficient removal of ciprofloxacin: Effect of pyrolysis temperature

Biochar preparation and application is an anticipated pathway for the resource utilization of biogas residue. In this study, biochars were prepared by the pyrolysis of biogas residue from food waste anaerobic digestion (named as BRBCs) under various pyrolysis temperatures (300, 500, 700, and 900 °C), and the effect of pyrolysis temperatures on the physicochemical characteristics of BRBCs was examined. The adsorption performance toward ciprofloxacin (CIP), a typical antibiotic in waterbodies, was also investigated. The results showed that pyrolysis temperature significantly changed the physicochemical properties of BRBCs. In addition, the minerals in the biogas residue, especially SiO2, were rearranged to form a mesoporous structure in biochar through a self-template strategy (without activator). BRBC prepared at 900 °C exhibited a high specific surface area and pore volume, well-developed mesopore structure, and more carbon structure defects, and exhibited the largest CIP adsorption capacity with 70.29 mg g−1, which was ascribed to the combined interaction of pore diffusion, π–π interactions, hydrogen bonding, complexation, and electrostatic forces. Furthermore, the adsorption of CIP by BRBC900 was well described by two-compartment kinetic and Langmuir isotherm models. BRBC900 showed good adsorption performance toward CIP at pH 7–9. The adsorption of CIP by BRBC is a spontaneous, exothermic, entropy-increasing process. Moreover, BRBC also presented a good recycling potential. Therefore, the preparation of mesoporous biochar based on a self-template strategy not only provides an option for the resource utilization of biogas residue but also offers a new option for the treatment of antibiotic wastewater.

Synthesis of MIL-53(Fe) implanted carbon spheres derived from resorcinol-formaldehyde resins for fast adsorption of antibiotics: Enhanced adsorption and pH adaptability

This article prepared a series of MIL-53(Fe) implanted carbon spheres derived from resorcinol-formaldehyde resins for rapid adsorption of Ciprofloxacin (CIP) using a facile hydrothermal coupling calcination methodology. Results indicated that MIL53(Fe)@RF-800, which was calcined at 800 °C, demonstrated the highest CIP removal efficiency of up to 95% within 60 min in batch adsorption tests. Moreover, MIL53(Fe) @RF-800 could remove over 95.8% of CIP at an amount of 0.2 mg/L, while both Cl− and HCO3− had a negligible impact on the CIP adsorption. It is noteworthy that when there was NO3− or SO42− in the solution, the impact of CIP adsorption displayed an inhibitory trend overall. In addition, MIL53(Fe)@RF-800 exhibited a broad pH range adaptability (over 95% CIP removal efficiency at pH = 3.0–10.5), even under highly acidic (pH < 3.0) or alkaline (pH > 10.5) conditions, the adsorption capacity for CIP was greater than 85%. In conclusion, this study provides novel insights into the development of highly porous MIL-53(Fe)-based adsorbent for rapid and pH-unrestricted adsorption of antibiotics and offers the possibility of practical engineering applications.

Modulating of Bi2MoO6-based photocatalyst through manipulation of reactant ratios for enhanced visible light photocatalytic activity

In this work, a novel photocatalyst, comprising of Bi2MoO6 and Bi2O2(OH)(NO3), was successfully synthesized by the one-pot hydrothermal method, thereby illuminating an innovative avenue for structure modulation of Bi2MoO6. The characterizations proved the facile attainability of controllable modifications in the microstructure and morphology of Bi2MoO6. The comprehensive appraisal of the synergistic adsorption-photocatalytic performances of the composites in the context of ciprofloxacin (CIP) was carried out. The findings presented compelling evidence that the amalgamation of Bi2MoO6/Bi2O2(OH)(NO3) exhibited an extraordinary adsorption capacity and photocatalytic activity when compared with the pristine Bi2MoO6 and Bi2O2(OH)(NO3). By virtue of its high surface area and pore volume, the optimized BMO/BON manifested a CIP adsorption capacity that surpassed that of Bi2MoO6 and Bi2O2(OH)(NO3) by approximately 2.4 and 11.2 times, respectively. Furthermore, through the concerted effects of adsorption and photocatalytic degradation, BMO/BON demonstrated an impressive CIP removal efficiency of 99.2 % following a mere 30 min of visible light exposure. The reaction rate constant was found to be approximately 0.124 min−1 for BMO/BON, surpassing that of Bi2MoO6 and Bi2O2(OH)(NO3). The augmentation in the photocatalytic activity of BMO/BON can be ascribed to its diminutive crystalline dimensions, large specific surface area, and narrowed bandgap. Thus, this investigation introduces a practical and ingenious strategy for the tuning of the Bi2MoO6 structure by manipulation of reactant ratios, showcasing significant implications in the realm of catalysis.

Research on efficient removal of ciprofloxacin through sequential rice straw biochar modification via alkali activation and manganese oxides

Biochar is considered an environmentally friendly and cost-effective option for removing antibiotics from aqueous solutions. In this study, biochar derived from rice straw (RBC) was sequentially modified by KMnO4 and NaOH (Mn/Na-RBC) to achieve ciprofloxacin (CIP) removal. To explore the adsorption mechanisms between Mn/Na-RBC and CIP, the characterization analyses, adsorption isotherms, thermodynamics, and kinetics were investigated. The results revealed that Mn/Na-RBC significantly increased the specific surface area (154.12 m2·g–1), carbonization, and the number of oxygen-containing functional groups compared with pristine biochar, thereby substantially enhancing the CIP adsorption capacity. Through fitting of the adsorption model, it was found that the highest adsorption capacity was 32.25 mg·g–1 under acidic conditions (pH=3), and the pseudo-second-order and Freundlich model fit the adsorption behavior well. The main mechanisms of the adsorption process were pore filling, electrostatic interaction, H-bonding, π–π conjugation, n–π interaction and surface complexation. Moreover, the Mn/Na-RBC still exhibited a remarkable capacity to selectively adsorb CIP even in the presence of high ionic strengths. Thus, Mn/Na-RBC is a promising adsorbent for removing emerging contaminants from aquatic environments.

Hydroxyapatite incorporated metakaolin/sludge based geopolymer adsorbent for copper ions and ciprofloxacin removal: Synthesis, characterization and mechanisms

The efficacy of copper Cu(II) adsorption is significantly affected by the presence of antibiotics, such as ciprofloxacin (CIP). Therefore, researchers are highly interested in conducting extensive investigations on the simultaneous adsorption of Cu(II) and CIP. However, most of the adsorbents exhibited low adsorption capacity of CIP with increasing Cu(II) concentration due to the competition for adsorption sites. Hence, the integration of various adsorbents into a single composite could be an effective way to increase the adsorption sites. Thus, this study aims to incorporate hydroxyapatite (Hap) into metakaolin/sludge based geopolymer adsorbent for simultaneous adsorption of Cu(II) and CIP. The effect of different filler loading of Hap (1–3 %) on the metakaolin/sludge geopolymerization and also on the removal efficiency of Cu(II) and CIP were studied in a single and binary system. Moreover, the effects of varied concentrations of Cu(II) (0–100 mg/L) on the removal efficiency of CIP were investigated. Characterization techniques such as x-ray diffraction (XRD), fourier-transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), brunauer-emmett-teller (BET) and neutron tomography imaging were employed to characterize the physicochemical properties of the synthesized geopolymer. It was found that the Hap content has a significant impact on the removal efficiency of CIP and Cu(II). The addition of 2 % Hap providing more nucleation site for the increasing geopolymerization (C-A-S-H) and silicoalumino phosphate gel (SAP) leading to the formation of highly cross-linked geopolymer network and abundant active sites which would favour the adsorption. Moreover, the removal efficiency of CIP by 2 % Hap-geopolymer increased (25.6 % to 61.51 %) with increasing Cu(II) concentration by the complexation and bridging effect between Cu(II) and CIP resulting in the formation of GMK25S1-2Hap-Cu(II)-CIP complexes. Therefore, the hybrid method of geopolymer and Hap is an exceptionally efficient approach for the treatment of wastewater that comprises Cu(II) and CIP.

Efficient and reusable mesoporous silica structures for ciprofloxacin removal from water media

The present study aimed to evaluate the potential of mesoporous silica structures, synthesized by the sol-gel method, and using an inorganic precursor, in adsorbing the antibiotic ciprofloxacin (CIP) from water. The structures with the largest surface area and smallest pore size were selected for adsorption tests. Under optimal adsorption conditions, the results showed better correlation with the Langmuir isotherm for the non-porous SiO2 (SiO2–3) and with the Freundlich isotherm for the mesoporous SiO2 (M0.5-SiO2–3 and M1.5-SiO2–3). The kinetic parameters for all analyzed particles had a better fit to the pseudo second-order model. The highest adsorption capacity value obtained was 47.24 mg/g for M1.5-SiO2–3. The thermodynamic parameters indicated that the adsorption was spontaneous, endothermic, and mostly occurred through physical and multilayer adsorption mechanisms. By the analysis of intraparticle diffusion it is clear that a multistep adsorption process occurs, and therefore an adsorption mechanism was proposed. The influence of temperature, pH and presence of salt on the adsorption process was evaluated. The results show that increasing temperature favours adsorption, and that pH and the presence of ions directly influence the adsorption capacity of CIP, indicating that the major interactions controlling the process are mainly electrostatic. Reusability experiment was carried out for M1.5-SiO2–3, being possible to identify that after 5 adsorption-desorption cycles, the adsorbent still has significant CIP adsorption capacity. Based on the results the feasibility of synthesizing mesoporous structures, using a facile method, with high CIP adsorption capacity was demonstrated.

Bioinspired Stevia rebaudiana Green Zinc Oxide Nanoparticles for the Adsorptive Removal of Antibiotics from Water.

Green zinc oxide nanoparticles (ZnO NPs) synthesized using Stevia rebaudiana as a reducing agent were investigated as ecofriendly adsorbents for the removal of the antibiotics ciprofloxacin (CIP) and tetracycline (TET) from water. Green ZnO NPs were synthesized using a rapid novel approach that did not require annealing or calcination at high temperatures to produce mesoporous NPs with a size range of 37.36-71.33 nm, a specific surface area of 15.28 m2/g, and a negative surface charge of -15 mV at pH 5. The green ZnO NPs exhibited an antioxidant activity of 85.57% at 250 μg/mL and an antibacterial activity with MIC and MBC of 50 and 100 mg/mL, respectively, against both Escherichia coli and Staphylococcus aureus. The best adsorption performance was achieved using a 4 g/L dose and pH 5, yielding, respectively, 86.77 ± 0.82% removal and 27.07 ± 0.26 mg/g adsorption capacity for CIP at 10 mg/L and 67.86 ± 3.41% and 15.88 ± 0.37 mg/g for TET at 25 mg/L. The green ZnO NPs achieved 79.71% ± 0.28 and 61.55% ± 0.53 removal of 10 mg/L CIP and 25 mg/L TET, respectively, in a spiked tap water binary system of the two contaminants. Adsorption of CIP and TET occurred mainly via electrostatic interactions, whereby CIP was bound more strongly than TET by virtue of its charge and size. The synthesis and adsorption processes were evaluated by a stepwise regression statistical model to optimize their parameters. Lastly, the green ZnO NPs were regenerated and reused for 5 cycles, indicating their functionality as simple, reusable, and low-cost adsorbents for the removal of CIP and TET from wastewater, in accordance with SDGs #6 and 12 for the sustainable management of water.

Facile and green synthesis of lignin-based aggregate microparticles adsorbent with hydrothermal regeneration function for ciprofloxacin removal from water

Lignin and its derivatives composites have received increasing interests in the field of water treatment for the features of eco-friendliness, cost-effectiveness and sustainable regeneration. Herein, a lignin-based aggregate microparticles adsorbent (SLS/PEI/GO-P) was synthesized through a green method for the adsorption of ciprofloxacin (CIP) in water. The composition and structure of SLS/PEI/GO-P were characterized by SEM, TEM, FT-IR, TG, XRD, XPS and N2 adsorption-desorption isotherm. The effects of adsorbent dosage, pH, concentration, time, temperature, inorganic salts and HA on CIP adsorption were investigated through batch experiments. The results indicated that the maximum CIP adsorption capacity was 823.3 mg/g with the CIP concentration of 250 mg/L at pH 8 and 30 ℃, which was much higher than that of most reported. The adsorption kinetics followed the pseudo-second-order model, and the adsorption isotherms followed the Langmuir model. The adsorption thermodynamic study indicated that the adsorption process was spontaneous at low temperatures and exothermic. FTIR and XPS analysis indicated that the adsorption mechanism was mainly involved with electrostatic interactions, hydrogen bonding interactions and π-π interactions. After 5 adsorption and hydrothermal regeneration cycles, the adsorption capacity for CIP by the adsorbent decreased only slightly. The adsorbent has the advantages of green preparation process and regeneration method, good adsorption capacity, and high sustainability, which renders it potentially viable in treating real wastewater containing CIP.

Enhancing adsorption capacity of magnetic magnesium-aluminum layered double hydroxide by surface modification with sodium dodecyl sulfate for efficient removal of organic contaminants

A magnetic magnesium-aluminum layered double hydroxide (Mag-MgAl) was prepared, and its surface was modified using surfactant sodium dodecyl sulfate (SDS) and utilized as adsorbents for antibiotic ciprofloxacin (CIP) and dyes ponceau red (PR) and methylene blue (MB). Mag-MgAl/SDS demonstrated twice the adsorption capacity for CIP compared to Mag-MgAl, confirming that the surface modification by SDS aided the adsorption capacity. At pH 3.5, Mag-MgAl removed CIP and PR, attributed to electrostatic effect and hydrogen bonding, whereas it did not interact with MB. Conversely, Mag-MgAl/SDS successfully removed both MB and CIP, suggesting that SDS micelles acted as nanoreactors attracting cationic contaminants. The PR removal efficiency was low, possibly due to electrostatic repulsion. A binary dye system adsorption assessment was performed by mixing MB and PR aqueous solutions with Mag-MgAl and Mag-MgAl/SDS as selective adsorbents. Mag-MgAl removed around 80% of PR and 45% of MB, whereas Mag-MgAl/SDS removed less than 40% of PR and 80% of MB. SDS remains adsorbed on the surface of Mag-MgAl/SDS after the adsorption process of CIP, MB, or PR. The inversion in the affinity for the target molecules suggests that the surface of the composite can be adjusted to modulate the behavior of the adsorbent toward organic contaminants.

Efficient removal of heavy metal and antibiotics from wastewater by phosphate-modified hydrochar

The preparation, characterization and adsorption performance of the phosphate-modified hydrochar (P-hydrochar) for Pb(II) and ciprofloxacin removal are investigated. Pb(II) and ciprofloxacin adsorption behavior fit well with the Hill model with the adsorption capacity of 119.61 and 98.38 mg/g, respectively. Pb(II) and ciprofloxacin adsorption kinetic process are accurately described by the Pseudo-second-order. Pb(II) and ciprofloxacin have synergy in the binary contaminant system, which reveals that Pb(II) adsorption amount is augmented. While ciprofloxacin adsorption amount is also augmented at low Pb(II) concentration and hindered at high Pb(II) concentration. Pb(II) adsorption mechanisms on P-hydrochar (e.g. precipitation, π-π interaction and complexation) are different from the ciprofloxacin (e.g. hydrogen bonding, pore filling, electrostatic attraction). Pb(II) and ciprofloxacin adsorption process are further analyzed by the density functional theory. The coexisted ions have little influenced on Pb(II) and ciprofloxacin adsorption. P-hydrochar still has large Pb(II) and ciprofloxacin adsorption capacity after five cycles. This result indicates that poplar sawdust waste can be converted into an efficient adsorbent to remove Pb(II) and ciprofloxacin from wastewater,.

Distinguishable adsorption interaction of virgin and biofilm covered polyethylene and polylactic acid for antibiotics

Microorganisms easily colonize microplastics in aquatic environment, forming microplastic circles with a high affinity for contaminants. However, the mechanism of antibiotic adsorption by biodegradable and non-biodegradable microplastics under biofilm loading is unclear. Here, virgin polyethylene (V-PE) and virgin polylactide (V-PLA) are non-biodegradable and biodegradable microplastics, respectively, and we investigated their biofilms formation in an aquatic environment. And the adsorption interaction of tetracycline hydrochloride (TCH) or ciprofloxacin (CIP) using biofilm covered polyethylene (B-PE) and compared it with biofilm covered polylactic acid (B-PLA). The biofilms changed the surface properties and morphology of the microplastics and enhanced their adsorption capacity for antibiotics. The order of adsorption capacity was B-PE > B-PLA > V-PE > V-PLA. Compared with V-PE and V-PLA, the adsorption capacity of B-PE and B-PLA for TCH increased by 0.346 and 0.267 mg/g, and adsorption capacity for CIP increased by 0.308 and 0.111 mg/g, respectively. The adsorption behaviors of B-PE and B-PLA fitted the pseudo-second-order kinetic equation well, and also fitted the Langmuir isotherm equation and the Freundlich isotherm equation, respectively. In addition, hydrogen-bond interaction, electrostatic interaction and hydrophobic interaction were found to dominate the adsorption of antibiotic by biofilm covered microplastics. Our study revealed the adsorption interaction between biofilm covered microplastics and antibiotics and provided basic information for ecological risk assessment of different biofilm covered microplastics.

Highly efficient adsorption of antibiotic ciprofloxacin hydrochloride from aqueous solution by diatomite-basic zinc chloride composites.

The antibiotic ciprofloxacin (CIP) is used to treat a variety of bacterial infections, yet it poses significant health risks to aquatic environments. While adsorption is a promising technique for CIP removal, current adsorption capacities remain limited. In this study, we introduce a diatomite and basic zinc chloride composite (ZnHC-Dt) prepared using a straightforward deposition method, with the ability to achieve highly efficient ciprofloxacin removal. ZnHC-Dt is characterized using field emission scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), and the Brunauer-Emmett-Teller method (BET). We also assess the zeta potential. The optimized ZnHC-Dt adsorbent, achieved at a mass ratio of 0.45 with ZnHC/(ZnHC+Dt), is adopted with a CIP adsorption capacity of 831.96 mg/g at 25 °C, broad pH adaptability (within 3.0-10.0), rapid adsorption rate (reaching equilibrium in 4 h), and stable performance under Na+ ionic strength. The CIP adsorption process follows pseudo-second-order kinetics and aligns well with the Langmuir adsorption model. The high adsorption capacity of ZnHC-Dt can be attributed to electrostatic attraction, hydrogen bonding, surface complexation, and available adsorption sites. During the desorption process, the CIP removal rate retains 65.33% effectiveness after five cycles. The results suggest that ZnHC-Dt holds significant potential for CIP removal in aqueous solutions.

Exploring the adsorption potential of Na2SiO3-activated porous carbon materials from waste bamboo biomass for ciprofloxacin rapid removal in wastewater

Effective utilization of biomass waste has become a key focus in achieving a sustainable future, considering the substantial amount of waste generated globally. This study investigates the characterization and evaluation of Na2SiO3-activated carbon derived from moso bamboo at various temperatures (500–900 °C) and residence time periods (30, 90, and 120 mins at 900 °C) for ciprofloxacin removal in aqueous solutions at initial concentrations of 50–250 mg/L. The activated carbons were characterized using N2 adsorption isotherms, revealing a combined Type I and Type IV behavior. The specific surface area (SBET) and total pore volume increased with increasing activation temperature, ranging from 157.3 m2/g to 381.6 m2/g. Regarding residence time, the SBET followed the sequence: Na2SiO3-60 (381.6 m2/g) > Na2SiO3-90 (333.8 m2/g) > Na2SiO3-120 (323.6 m2/g) > Na2SiO3-30 (312.7 m2/g). XRD analysis indicated a distinct peak at 23°, corresponding to the (002) plane of amorphous carbon, while Raman spectroscopy confirmed the presence of the D band and G band, indicating an amorphous carbon structure (ID/IG > 1). The adsorption performance of ciprofloxacin (CIP) on the activated carbons was evaluated at 298 K. The highest CIP removal rate of 89.2% was achieved within one hour using Na2SiO3-900, followed by Na2SiO3-800, Na2SiO3-700, Na Na2SiO3-600, and Na2SiO3-500, consistent with the SBET trend. The Langmuir adsorption isotherm model provided the best fit for analyzing the adsorption process, indicating predominantly monolayer adsorption, while the Freundlich model was suitable for ACs with different residence times. The maximum adsorption capacity of CIP was recorded for Na2SiO3-30 AC (17.12 mg/g). In conclusion, the synthesized activated carbons show promising potential as adsorbents for ciprofloxacin removal from water.

Adsorption of antibiotics on montmorillonite and site energy distribution analysis

The migration and transformation of antibiotics requires further study in geochemical settings. In this study, the removal effect of montmorillonite (Mt) on antibiotics was investigated, using the broad-spectrum antibiotics ciprofloxacin (CIP) and erythromycin (ERY) as subjects. The results of adsorption kinetics and adsorption isotherm experiments showed that the generalized Langmuir model describe the adsorption process well, and the adsorption capacity of CIP was higher. The intercalation and adsorption behaviors of CIP and ERY on Mt surface were analyzed by FT-IR, SEM, TEM, XRD and Molecular simulation. In order to analyze the different adsorption capacity of these antibiotics on Mt, the theory of site energy distribution was employed. By fitting the experimental data with the Generalized-Langmuir model, the site energy distribution and average site energy were calculated, which revealed the competitive adsorption mechanism of CIP and ERY on Mt. Moreover, the adsorption of antibiotics on Mt under different pH conditions was studied, and the competitive adsorption results were also demonstrated by the potential energy distribution.

Important effects of polypropylene on migration of ciprofloxacin in groundwater

To investigate the effect of microplastics on the transport and retention of antibiotics in subsurface environment, polypropylene (PP) and ciprofloxacin (CIP) are selected as typical microplastic and antibiotic contaminant, respectively. The key factors and main control mechanisms are systematically investigated using a combination of adsorption experiments, column experiments and numerical model. The adsorption experiments indicate the largest adsorption capacity of CIP on PP is 1.03 mg·g−1. Simultaneously, the results of column experiments and numerical model suggest that PP can significantly affect the migration behavior and retention of CIP in porous media. CIP mobility is positively correlated to flow velocity, initial concentration of CIP and ionic strength (Na+, Ca2+ and Ba2+). Moreover, compared to monovalent cation (Na+), divalent cations (Ca2+, Ba2+) have a stronger enhancement effect on CIP mobility and a stronger inhibition effect on CIP retention in saturated porous media. The transport of CIP in saturated porous media containing PP is simulated by a single-point kinetic model, and the equations of the transport kinetic parameters of CIP are obtained through regression analysis. The research could help to gain insight into understanding the environmental behavior of antibiotic in the groundwater system, and provide scientific basis for the accurate prediction and assessment of environmental risk caused by microplastic and antibiotic in the groundwater system.