Adsorptive Removal of Azithromycin Antibiotic from Aqueous Solution by Azolla Filiculoides-Based Activated Porous Carbon

Impact of the hydrated functional zone on the adsorption of ciprofloxacin to microplastics under the influence of UV aging

The inevitable UV aging of microplastics (MPs) is one of the key factors affecting their interaction with antibiotics. In this study, polyethylene (PE) and polystyrene (PS) MPs were aged with UV irradiation. The adsorption isotherms and kinetics of ciprofloxacin (CIP) to virgin and aged MPs were investigated through various models, and the effects of pH on the adsorption amount were explored. Characterization revealed that the surfaces of aged MPs became rougher, and the hydrophilicity increased. These aged MPs were still in the early stage of aging on the basis of their carbonyl index (CI) (<0.2) and O/C (<0.04) values. The adsorption isotherms indicated that the adsorption mechanism of aged PE was different from that of virgin PE. Compared with virgin PE, the adsorption amount of aged PE increased by 87.80-95.45%, and the adsorption rate decreased by 65.52-80.74%. However, aging did not significantly affect the equilibrium adsorption amount or adsorption rate of aged PS. The external diffusion rate (Kext) (about 2.29-0.36 h-1) was almost 30 times greater than the internal diffusion rate (Kint) in the film-pore mass transfer (FPMT) model, indicating that CIP adsorption rate was dominated by external diffusion. A hydrated functional zone is thought to form around aged MPs, thus changing the adsorption mechanism and adsorption amount of aged PE. Therefore, more attention should be given to alterations in the hydrated functional zone in the early stage of MPs aging.

Adsorptive removal of anticarcinogen pazopanib from aqueous solutions using activated carbon: isotherm, kinetic and thermodynamic studies

Pazopanib, which is dangerous for aquatic environments due to its toxic and bioaccumulation potential, has been detected at different concentrations in oncology hospital wastewater, sewage, and surface waters. This study aimed to remove pazopanib from wastewater by activated carbon adsorption technique. The effect of the main variables such as initial concentration, pH of pazopanib solution, adsorbent dose, contact time of the phases, and temperature on the adsorption process was evaluated and the optimum adsorption conditions were determined. The experimental data were applied to Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich adsorption isotherm models to describe the adsorption behavior. The experimental data were applied to pseudo-first-order, pseudo-second-order, and intra-particle diffusion kinetic models to describe the adsorption kinetics. Isotherms were established in the 20-50 °C temperature range to study the adsorption equilibrium. According to the results, the highest removal efficiency of pazopanib (95.87%) was obtained at initial concentration (100 mg L-1), adsorbent dose (0.30 g L-1), temperature (20 °C), contact time (120 min) and pH (7.0). The adsorption kinetics was well described by the pseudo-second-order kinetic model (R2 = 0.9998) and the adsorption isotherm by the Langmuir model (R2 = 0.9999). In thermodynamic studies, the negative values of standard enthalpy (ΔH°), standard free enthalpy (ΔG°), and free entropy (ΔS°) indicate that the adsorption process is spontaneous and favorable, i.e. the disorder is reduced. These results indicate that the developed adsorption process can be efficiently and spontaneously applied for the removal of pazopanib from aqueous solutions.

Azithromycin removal using pine bark, oak ash and mussel shell

Adsorption is considered an interesting option for removing antibiotics from the environment because of its simple design, low cost, and potential efficiency. In this work we evaluated three by-products (pine bark, oak ash, and mussel shell) as bio-adsorbents for the antibiotic azithromycin (AZM). Furthermore, they were added at doses of 48 t ha-1 to four different soils, then comparing AZM removal for soils with and without bio-adsorbents. Batch-type experiments were used, adding AZM concentrations between 2.5 and 600 μmol L-1 to the different bio-adsorbents and soil + bio-adsorbent mixtures. Regarding the bio-adsorbents, oak ash showed the best adsorption scores (9600 μmol kg-1, meaning >80% retention), followed by pine bark (8280 μmol kg-1, 69%) and mussel shell (between 3000 and 6000 μmol kg-1, 25-50% retention). Adsorption data were adjusted to different models (Linear, Freundlich and Langmuir), showing that just mussel shell presented an acceptable fitting to the Freundlich equation, while pine bark and oak ash did not present a good adjustment to any of the three models. Regarding desorption, the values were always below the detection limit, indicating a rather irreversible adsorption of AZM onto these three by-products. Furthermore, the results showed that when the lowest concentrations of AZM were added to the not amended soils they adsorbed 100% of the antibiotic, whereas when the highest concentrations of AZM were spread, the adsorption decreased to 55%. However, when any of the three bio-adsorbents was added to the soils, AZM adsorption reached 100% for all the antibiotic concentrations used. Desorption was null in all cases for both soils with and without bio-adsorbents. These results, corresponding to an investigation carried out for the first time for the antibiotic AZM, can be seen as relevant in the search of low-cost alternative treatments to face environmental pollution caused by this emerging contaminant.

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.

Superior adsorption and removal of doxorubicin from aqueous solution using activated carbon via thermally treated green adsorbent: isothermal, kinetic, and thermodynamic studies

Activated carbon from apricot seeds (ASAC) was successfully made using a low-cost, straightforward synthesis process. With the use of various instruments, including XRD, XPS, FT-IR, SEM, and TEM, the adsorbent was demonstrated. The surface area of the ASAC that was given was also shown to be 436.8 m2/g. It was discovered that the synthesized ASAC has a fantastic capacity to absorb the anti-cancer medication doxorubicin hydrochloride (DOX). Based on changes in temperature, pH, and DOX concentration, The DOX adsorption behaviour's mechanism was evaluated. The adsorption capacity of ASAC for DOX was greater at pH 6.0, according to experimental data as the adsorption capacity was discovered to be 951.13 mg/g. Adsorption equilibrium analysis revealed that, when compared to the other models, the Langmuir adsorption provided the best fit to the data that were collected. Additionally, The ASAC has validated the DOX activation energy of adsorption as a chemisorption technique. The kinetics of adsorption were shown to be fitted to pseudo-second-order kinetic model. The reaction was endothermic and spontaneous, according to thermodynamic data. Innvestigation the removal efficiency of ASAC to remove DOX from real watrer sample (tap water, effluent wastewater, and impact wastewater). It was suggested by the results that ASAC was a viable option for treating wastewater and adsorbing DOX. The synthesized ASAC has noteworthy cyclability and reusability characteristics due to its high efficiency (up to five cycles) and low cost (around 86 percent).

A comprehensive review on the fate and impact of antibiotic residues in the environment and public health: A special focus on the developing countries

The widespread application of antibiotics in human and veterinary medicine has led to the pervasive presence of antibiotic residues in the environment, posing a potential hazard to public health. This comprehensive review aims to scrutinize the fate and impact of antibiotic residues, with a particular focus on the context of developing nations. The investigation delves into the diverse pathways facilitating the entry of antibiotics into the environment and meticulously examines their effects on human health. The review delineates the current state of antibiotic residues, evaluates their exposure in developing nations, and elucidates existing removal methodologies. Additionally, it probes into the factors contributing to the endurance and ecotoxicity of antibiotic residues, correlating these aspects with usage rates and associated mortalities in these nations. The study also investigates removal techniques for antibiotic residues, assessing their efficiency in environmental compartments. The concurrent emergence of antibiotic-resistant bacteria, engendered by antibiotic residues, and their adverse ecological threats underscore the necessity for enhanced regulations, vigilant surveillance programs, and the adoption of sustainable alternatives. The review underlines the pivotal role of public education and awareness campaigns in promoting responsible antibiotic use. The synthesis concludes with strategic recommendations, strengthening the imperative for further research encompassing comprehensive monitoring, ecotoxicological effects, alternative strategies, socio-economic considerations, and international collaborations, all aimed at mitigating the detrimental effects of antibiotic residues on human health and the environment. PRACTITIONER POINTS: Antibiotic residues are widely distributed in different environmental compartments. Developing countries use more antibiotics than developed countries. Human and veterinary wastes are one of the most responsible sources of antibiotic pollution. Antibiotics interact with biological systems and trigger pharmacological reactions at low doses. Antibiotics can be removed using modern biological, chemical, and physical-chemical techniques.

Synthesis and characterization of titanium dioxide nanoparticles from Bacillus subtilis MTCC 8322 and its application for the removal of methylene blue and orange G dyes under UV light and visible light

Over the last decade there has been a huge increase in the green synthesis of nanoparticles. Moreover, there is a continuous increase in harnessing the potential of microorganisms for the development of efficient and biocompatible nanoparticles around the globe. In the present research work, investigators have synthesized TiO2 NPs by harnessing the potential of Bacillus subtilis MTCC 8322 (Gram-positive) bacteria. The formation and confirmation of the TiO2 NPs synthesized by bacteria were carried out by using UV-Vis spectroscopy, Fourier transforms infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDX/EDS). The size of the synthesized TiO2 NPs was 80-120 nm which was spherical to irregular in shape as revealed by SEM. FTIR showed the characteristic bands of Ti-O in the range of 400-550 cm-1 and 924 cm-1 while the band at 2930 cm-1 confirmed the association of bacterial biomolecules with the synthesized TiO2 NPs. XRD showed two major peaks; 27.5° (rutile phase) and 45.6° (anatase phase) for the synthesized TiO2 NPs. Finally, the potential of the synthesized TiO2 NPs was assessed as an antibacterial agent and photocatalyst. The remediation of Methylene blue (MB) and Orange G (OG) dyes was carried out under UV- light and visible light for a contact time of 150-240 min respectively. The removal efficiency for 100 ppm MB dye was 25.75% and for OG dye was 72.24% under UV light, while in visible light, the maximum removal percentage for MB and OG dye was 98.85% and 80.43% respectively at 90 min. Moreover, a kinetic study and adsorption isotherm study were carried out for the removal of both dyes, where the pseudo-first-order for MB dye is 263.269 and 475554.176 mg/g for OG dye. The pseudo-second-order kinetics for MB and OG dye were 188.679 and 1666.667 mg/g respectively. In addition to this, the antibacterial activity of TiO2 NPs was assessed against Bacillus subtilis MTCC 8322 (Gram-positive) and Escherichia coli MTCC 8933 (Gram-negative) where the maximum zone of inhibition in Bacillus subtilis MTCC 8322 was about 12 mm, and for E. coli 16 mm.

Efficiency of Fe3O4@ZIF-8 for the removal of Doxorubicin from aqueous solutions: equilibrium, kinetics and thermodynamic studies

Due to inadequate pharmaceutical wastewater treatment, anticancer contaminants from the pharmaceutical industry frequently end up in the aquatic environment where they endanger aquatic life and humans. As a result, the appropriate treatment of wastewater that contains anticancer agents is crucial for pollution prevention. The purpose of this work is to assess the effectiveness of a Fe3O4@ZIF-8 nanocomposite as an adsorbent to remove of the chemotherapeutic drugs doxorubicin (DOX) from aqueous solution. SEM, XRD, BET, FT-IR, Zeta potential, and point of zero charge analysis were used to study the surface and structural characteristics of the Fe3O4@ZIF-8 nanocomposite. Via the proposed treatment, 804.84 mg/g elimination was successful under the following circumstances: pH = 6; Fe3O4@ZIF-8 dose = 0.02 g/25 mL; DOX concentration = 1.22x10-3 mol; adsorption time = 100 min; and shaking speed = 200 rpm. A investigation of isotherms shown that the Langmuir equation and experimental data suited each other quite well. The adsorption of DOX on Fe3O4@ZIF-8 was endothermic and spontaneous, in accordance with thermodynamic properties. Furthermore, the elimination of DOX was enhanced by the rise in solution temperature. The kinetic analysis revealed that the pseudo-second order was fitted by the model. The suggested adsorption method could recycle Fe3O4@ZIF-8 nanocomposite six times, with a modest reduction in its ability for adsorption. For all XRD reflection peaks, physical characteristics including strain rates were computed and the dislocation of was 4.7 × 10-6. Investigate the activity of the DOX towards COVID-19, breast and prostate cancer using molecular docking.

Application of Metal-Organic Frameworks for Efficient Removal of Doxorubicin Hydrochloride: Removal Process Optimization and Biological Activity

This study looked at the doxorubicin hydrochloride (DOX) anticancer drug's adsorption characteristics on a silver-based metal-organic framework (Ag-MOF). X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were used for the characterization of Ag-MOF. The pore volume and surface area of Ag-MOF were determined through Brunauer-Emmett-Teller (BET) testing at 77 K to be 0.509 cm3/g and 676.059 m2/g, respectively. Adsorption at pH 6 was established to be the best for DOX compared to alkaline solution. Ag-MOF has a good capacity for eliminating DOX (1.85 mmol/g), according to adsorption experiments. From the adsorption results, we can find that Langmuir is the most fitted adsorption isotherm model and the pseudo-second order model best fitted the adsorption kinetics. The energy of activation for adsorption, which was determined to be 15.23 kJ/mol, also supported a chemisorption process. The mechanism of adsorption was evaluated, and details of all possible interactions between DOX and Ag-MOF were illustrated. On the other hand, while examining the impact of temperature, we identified the thermodynamic constraints as ΔG°, ΔH°, and ΔS° and confirmed that the reaction was an endothermic one and spontaneous. Even after numerous reuse cycles, the efficiency remained constant. The synthetic adsorbent was remarkably recyclable at a rate of more than 91.6%. By using the MTT assay, the cytotoxicity of the tested Ag-MOF and DOX@Ag-MOF against human breast cancer cells (MCF-7) was evaluated in vitro. The in vitro antimicrobial activity of Ag-MOF and DOX@Ag-MOF was also tested.

Modeling of adsorptive removal of azithromycin from aquatic media by CoFe2O4/NiO anchored microalgae-derived nitrogen-doped porous activated carbon adsorbent and colorimetric quantifying of azithromycin in pharmaceutical products

Herein, it was aimed to optimize the removal process of Azithromycin (Azi) from the aquatic environment via CoFe2O4/NiO nanoparticles anchored onto the microalgae-derived nitrogen-doped porous activated carbon (N-PAC), besides developing a colorimetric method for the swift monitoring of Azi in pharmaceutical products. In this study, the Spirulina platensis (Sp) was used as a biomass resource for fabricating CoFe2O4/NiO@N-PAC adsorbent. The pores of N-PAC mainly entail mesoporous structures with a mean pore diameter of 21.546 nm and total cavity volume (Vtotal) of 0.033578 cm3. g-1. The adsorption studies offered that 98.5% of Azi in aqueous media could remove by CoFe2O4/NiO@N-PAC. For the cyclic stability analysis, the adsorbent was separated magnetically and assessed at the end of five adsorption-desorption cycles with a negligible decrease in adsorption. The kinetic modeling revealed that the adsorption of Azi onto the CoFe2O4/NiO@N-PAC was well-fitted to the second-order reaction kinetics, and the highest adsorption capacity was found as 2000 mg. g-1 at 25 °C based on the Langmuir adsorption isotherm model at 0.8 g. L-1 adsorbent concentration. The Freundlich isotherm model had the best agreement with the experimental data. Thermodynamic modeling indicated the spontaneous and exothermic nature of the adsorption process. Moreover, the effects of pH, temperature, and operating time were also optimized in the colorimetric Azi detection. The blue ion-pair complexes between Azi and Coomassie Brilliant Blue G-250 (CBBG-250) reagent followed Beer's law at wavelengths of 640 nm in the concentration range of 1.0 μM to 1.0 mM with a 0.94 μM limit of detection (LOD). In addition, the selectivity of Azi determination was verified in presence of various species. Furthermore, the applicability of CBBG-250 dye for quantifying Azi was evaluated in Azi capsules as real samples, which revealed the acceptable recovery percentage (98.72-101.27%). This work paves the way for engineering advanced nanomaterials for the removal and monitoring of Azi and assures the sustainability of environmental protection and public health.

Hierarchically porous graphene-like biochar for efficient removal of aromatic pollutants and their structure-performance relationship: A combined experimental, MD and DFT study

Development of high-efficiency adsorbents and exploration of the structure-performance relationship holds exciting implications for removal of aromatic pollutants (APs) from water. Herein, hierarchically porous graphene-like biochars (HGBs) were successfully prepared by K₂CO₃ simultaneous graphitization and activation of Physalis pubescens husk. The HGBs possess high specific surface area (1406-2369.7 m²/g), hierarchically meso-/microporous structure and high graphitization degree. The optimized HGB-2-9 sample exhibits rapid adsorption equilibrium time (t_e) and high adsorption capacities (Q_e) for seven widely-used persistent APs with different molecular structures (e.g., phenol: t_e = 7 min, Q_e = 191.06 mg/g; methylparaben: t_e = 12 min Q_e = 482.15 mg/g). HGB-2-9 also shows a wide pH (3-10) suitability and good ionic strength (0.01-0.5 M NaCl) resistance properties. The effects of the physicochemical properties of HGBs and APs on the adsorption performance were deeply investigated by the adsorption experiments, molecular dynamics (MD) and density functional theory (DFT) simulation. The results demonstrate that the large specific surface area, high graphitization degree and hierarchically porous structure of HGB-2-9 can supply more active sites on accessible surface and facilitate the transport of APs. And the aromaticity and hydrophobicity of APs play the more crucial roles during the adsorption process. Besides, the HGB-2-9 presents good recyclability and high removal efficiency for APs in various real water, which further confirms its potential for practical applications.

Valorization of Ginger Waste-Derived Biochar for Simultaneous Multiclass Antibiotics Remediation in Aqueous Medium

The presence of antibiotics in the aqueous environment has been a serious concern primarily due to the development of antimicrobial resistance (AMR) in diverse microbial populations. To overcome the rising AMR concerns, antibiotic decontamination of the environmental matrices may play a vital role. The present study investigates the use of zinc-activated ginger-waste derived biochar for the removal of six antibiotics belonging to three different classes, viz., β-lactams, fluoroquinolones, and tetracyclines from the water matrix. The adsorption capacities of activated ginger biochar (AGB) for the concurrent removal of the tested antibiotics were investigated at different contact times, temperatures, pH values, and initial concentrations of the adsorbate and adsorbent doses. AGB demonstrated high adsorption capacities of 5.00, 17.42, 9.66, 9.24, 7.15, and 5.40 mg/g for amoxicillin, oxacillin, ciprofloxacin, enrofloxacin, chlortetracycline, and doxycycline, respectively. Further, among the employed isotherm models, the Langmuir model fitted well for all the antibiotics except oxacillin. The kinetic data of the adsorption experiments followed the pseudo-second order kinetics suggesting chemisorption as the preferred adsorption mechanism. Adsorption studies at different temperatures were conducted to obtain the thermodynamic characteristics suggesting a spontaneous exothermic adsorption phenomenon. AGB being a waste-derived cost-effective material shows promising antibiotic decontamination from the water environment.

Nanostructured Materials and Advanced Processes for Application in Water Purification

Water pollution is a major environmental problem that has a significant impact on human and animal health and the ecosystem [...].

Adsorptive removal of antibiotic pollutants from wastewater using biomass/biochar-based adsorbents

This study explores adsorptive removal measures to shed light on current water treatment innovations for kinetic/isotherm models and their applications to antibiotic pollutants using a broad range of biomass-based adsorbents. The structure, classifications, sources, distribution, and different techniques for the remediation of antibiotics are discussed. Unlike previous studies, a wide range of adsorbents are covered and adsorption of comprehensive classes of antibiotics onto biomass/biochar-based adsorbents are categorized as β-lactam, fluoroquinolone, sulfonamide, tetracycline, macrolides, chloramphenicol, antiseptic additives, glycosamides, reductase inhibitors, and multiple antibiotic systems. This allows for an assessment of their performance and an understanding of current research breakthroughs in applying various adsorbent materials for antibiotic removal. Distinct from other studies in the field, the theoretical basis of different isotherm and kinetics models and the corresponding experimental insights into their applications to antibiotics are discussed extensively, thereby identifying the associated strengths, limitations, and efficacy of kinetics and isotherms for describing the performances of the adsorbents. In addition, we explore the regeneration of adsorbents and the potential applications of the adsorbents in engineering. Lastly, scholars will be able to grasp the present resources employed and the future necessities for antibiotic wastewater remediation.

Adsorptive removal of levofloxacin and antibiotic resistance genes from hospital wastewater by nano-zero-valent iron and nano-copper using kinetic studies and response surface methodology

In the twenty-first century, water contamination with pharmaceutical residues is becoming a global phenomenon and a threat. Antibiotic residues and antibiotic resistance genes (ARGs) are recognized as new emerging water pollutants because they can negatively affect aquatic ecosystems and human health, thereby posing a complex environmental problem. These nano-adsorbents of the next generation can remove these pollutants at low concentrations. This study focuses on the chemical synthesis of copper oxide nanoparticles (CuONPs) and nano-zero-valent iron (nZVI) used as nano-adsorbents for levofloxacin removal from water samples and antibiotic-resistant genes. The CuONPs and nZVI are initially characterized by transmission electron microscopy, scanning electron microscopy, and X-ray diffraction. The levofloxacin adsorption isotherm on the CuONPS and nZVI shows the best fit with the Langmuir isotherm model, exhibiting correlation coefficients (R2) of 0.993 and 0.999, respectively. The adsorption activities of CuONPS and nZVI were fitted to a pseudo-second-order kinetic model with correlation coefficients (R2) of 0.983 and 0.994, respectively. The maximum levofloxacin removal capacity was observed at (89%), (84%), (89%), (88%) and (71.6) at pH 7 and adsorbent dose(0.06 mg/L), initial LEV concentration (1 mg/L), temperature 25 °C, and contact time 120 min for CuONPs. Removal efficiency was (91%), (90.6%), (91%), (89%), and (80%), at pH 7, adsorbent dose(0.06), initial LEV concentration (1 mg/L), temperature 35 °C, and contact time 120 min. The levofloxacin adsorption is an exothermic process for nZVI and CuONPs, according to thermodynamic analysis. A thermodynamic analysis indicated that each adsorption process is spontaneous. Several genera, including clinically pathogenic bacteria (e.g., Acinetobacter_baumannii, Helicobacter_pylori, Escherichia_coli, Pseudomonas_aeruginosa, Clostridium_beijerinckii, Escherichia/Shigella_coli, Helicobacter_cetorum, Lactobacillus_gasseri, Bacillus_cereus, Deinococcus_radiodurans, Rhodobacter_sphaeroides, Propionibacterium_acnes, and Bacteroides_vulgatus) were relatively abundant in hospital wastewater. Furthermore, 37 antibiotic resistance genes (ARGs) were quantified in hospital wastewater. The results demonstrated that 95.01% of nZVI and 91.4% of CuONPs are effective adsorbents for removing antibiotic-resistant bacteria from hospital effluent. The synthesized nZVI and CuONPs have excellent reusability and can be considered cost effective and eco-friendly adsorbents.

Fabricating of Fe3O4@Ag-MOF nanocomposite and evaluating its adsorption activity for removal of doxorubicin

The purpose of this research was to investigate the doxorubicin (DOX) adsorption behavior on Fe3O4@Ag-Metal Organic Framework (Fe₃O₄@Ag-MOF). This adsorbent was effectively prepared using a simple synthetic process. Many instruments, including FTIR, XRD, SEM, TEM, and XPS, were used to characterized the new Fe₃O₄@Ag-MOF. Additionally, the presented Fe₃O₄@Ag-surface MOF's area was shown to be 586.06 m2/g with a size of around 43 nm. The composite that was made has magnetic properties that were quite strong (63.3 emu/g). The produced Fe₃O₄@Ag-MOF was discovered to have a fantastic ability to adsorb the anti-cancer drug DOX, with a 1.72 mmol/g (934.85 mg/g) adsorption capacity. On the basis of changes in temperature, pH, and DOX concentration, the DOX adsorption behavior mechanism was investigated. The adsorption capacity of Fe₃O₄@Ag-MOF for DOX was greater at pH 7.0, according to experimental data. The adsorption equilibrium also demonstrated that the Langmuir adsorption was regulated the best fit to the extracted data compared with the other models. Additionally, the activation energy of adsorption for DOX onto Fe₃O₄@Ag-MOF was determined, indicating the chemisorption process. The adsorption kinetics was shown in the well-known kinetic model of the pseudo-second-order. The adsorption thermodynamic measurements were documented according to according to the enthalpy (ΔH°), entropy(ΔS°), and Gibbs free energy (ΔG°) parameters demonstrated that the reaction was endothermic and spontaneous thermodynamic. The adsorption of DOX onto Fe₃O₄@Ag-MOF from real water samples (tap water, effluent wastewater, and influence wastewater) were investigated. It's interesting that the synthetic adsorbent had great recyclability 72.6 percent in the fifth cycle indicating that it was highly recyclable. After adsorption, the typical Fe₃O₄@Ag-MOF XRD peak intensities and locations were mostly unchanged throughout adsorption indicates the crystalline phase remained steady. The results indicated that Fe₃O₄@Ag-MOF were a good candidate for adsorbing the DOX and treating wastewater.

Azithromycin Adsorption onto Different Soils

The antibiotic azithromycin (AZM) is one of the most persistent in the environment, with potential to cause serious health and environmental problems. As some polluting discharges containing this antibiotic can reach the soil, it is clearly relevant determining the ability of soils with different characteristics to retain it. In this research, AZM adsorption and desorption were studied for a variety of soils, using batch-type experiments. The results show that, at low doses of antibiotic added (less than or equal to 50 µmol L−1), the adsorption always reached 100%, while when higher concentrations were added (between 200 and 600 µmol L−1) the highest adsorption corresponded to soils with higher pH values. Adsorption data were fitted to the Linear, Langmuir and Freundlich models, with the latter showing the best fit, in view of the determination coefficient. No desorption was detected, indicating that AZM is strongly adsorbed to the soils evaluated, suggesting that the risks of environmental problems due to this contaminant are minimized for these edaphic media. These results can be considered relevant with respect to risk assessment and possible programming of measures aimed at controlling environmental contamination by emerging contaminants, especially from the group of antibiotics, and in particular from AZM.

Magnetic NH2-MIL-101(Al)/Chitosan nanocomposite as a novel adsorbent for the removal of azithromycin: modeling and process optimization

In the present study, the magnetic NH₂-MIL-101(Al)/chitosan nanocomposite (MIL/Cs@Fe₃O₄ NCs) was synthesized and used in the removal of azithromycin (AZT) from an aqueous solution for the first time. The as-synthesized MIL/Cs@Fe₃O₄ NCs was characterized by SEM, TEM, XRD, FTIR, BET, and VSM techniques. The effect of various key factors in the AZT adsorption process was modeled and optimized using response surface methodology based on central composite design (RSM-CCD). The low value of p-value (1.3101e-06) and RSD (1.873) parameters, along with the coefficient of determination > 0.997 implied that the developed model was well fitted with experimental data. Under the optimized conditions, including pH: 7.992, adsorbent dose: 0.279 g/L, time: 64.256 min and AZT concentration: 10.107 mg/L, removal efficiency and AZT adsorption capacity were obtained as 98.362 ± 3.24% and 238.553 mg/g, respectively. The fitting of data with the Langmuir isotherm (R²: 0.998, X²: 0.011) and Pseudo-second-order kinetics (R²: 0.999, X²: 0.013) showed that the adsorption process is monolayer and chemical in nature. ΔH° > 0, ΔS° > 0, and ∆G° < 0 indicated that AZT removal was spontaneous and endothermic in nature. The effect of Magnesium on AZT adsorption was more complicated than other background ions. Reuse of the adsorbent in 10 consecutive experiments showed that removal efficiency was reduced by about 30.24%. The performance of MIL/Cs@Fe₃O₄ NCs under real conditions was also tested and promising results were achieved, except in the treatment of AZT from raw wastewater.

Highly effective water hyacinth (Eichhornia crassipes) waste-based functionalized sustainable green adsorbents for antibiotic remediation from wastewater

Azithromycin (AZIM) is considered as one of the most frequently prescribed antibiotics (ABs) in the world by medical professionals. This study explored, two novel, cheap and environmentally beneficial adsorbents i.e., alkali treated water hyacinth powder (AT-WHP) and graphene oxide-water hyacinth-polyvinyl alcohol (GO-WH-PVA) composite, fabricated from water hyacinth (Eichhornia crassipes) waste to remediate AZIM from wastewater. Biosorption experiments were performed by batch and packed-bed column studies and the adsorbents were characterized using various instrumental methods. The morpho-chemical profile of the adsorbents suggested noteworthy AZIM adsorption. AZIM adsorption data can be reasonably explained by pseudo second order (PSO) kinetic model with maximum regression coefficient (R² > 0.99) and lowest Marquardt's present standard deviation (MPSD) and root mean squared error (RMSE) values. The isotherm models recommended Langmuir and Temkin to be the best-fitted, providing highest regression coefficient and lowest error values. Conferring to Langmuir model, the theoretical highest adsorption potentials (q_max) were accounted to be 244.498 and 338.115 mg/g for AT-WHP and GO-WH-PVA, correspondingly, very close to experimental values (q_e, exp). AZIM adsorption processes were governed by the chemisorption mechanisms. The adsorbents had excellent regeneration potential and could be reused several times. In order to scale-up application of the adsorbents, performance of a 100 L packed-bed reactor was assessed and a breakthrough time of adsorption for GO-WH-PVA was 15 min in 5000 mg/L AZIM concentration. Thus, the absorbents synthesized in this study can be considered highly effective at removal of AZIM from wastewater.