Cephalexin Adsorption Research Articles

Photocatalysis assisted by activated-carbon-impregnated magnetite composite for removal of cephalexin from aqueous solution

The simultaneous presence of antibiotics and bacteria in aqueous media has been recognized as an environmental threat, due to the enhancement of antibiotic resistance of bacteria. We synthesized an activated carbon impregnated magnetite composite (PAC/Fe3O4) and used it for removal of cephalexin (CEX) from aqueous solution via UV system. A series of batch experiments was carried out under various experimental conditions such as pH of solution (3–11), contact time (0–120 min), catalyst dosages (0.1–2 g/L) and initial CEX concentrations (10, 25, 50 and 100 mg/L). Some common isotherm models were used for study of CEX adsorption and finding the best model. In addition, kinetic studies of CEX photocatalytic removal were performed by fitting the experimental data on first-order and second-order models. Results of comparative studies showed that UV+PAC/Fe3O4 and UV+TiO2 systems, compared to UV/Fe3O4, naked Fe3O4, PAC/Fe3O4 and UV only, had more capability of removing CEX from aqueous solution, indicating PAC/Fe3O4 is effectively catalyzed by UV light. Furthermore, increasing catalyst dosages and decreasing initial CEX concentrations led to the enhancing photocatalytic removal of CEX from solution. The obtained results of kinetic studies also represent that among the studied models, second-order model with significant coefficient of correlation (R2) had higher ability than first-order model to fit the data of CEX removal. Finally, the findings of reusability tests, showed that the applied catalyst would be applicable for CEX removal, even after five consecutive cycles.

Application of ZnO and TiO2 nanoparticles coated onto montmorillonite in the presence of H2O2 for efficient removal of cephalexin from aqueous solutions

This study considers the feasibility of uptake of cephalexin, an emerging contaminant, from aqueous solutions by using green local montmorillonite (GLM), montmorillonite coated with ZnO (ZnO/GLM) and montmorillonite coated with TiO2 (TiO2/GLM) in the presence of H2O2. Batch adsorption experiments were carried out as a function of pH, initial concentration of the cephalexin, adsorbent dosage, contact time, and temperature. Finally, the adsorbents were characterized by XRD, SEM and FTIR analyses. XRD patterns showed dramatic changes in the adsorbents after loading with the nanoparticles, confirming successful placing of the nanoparticles onto GLM. The GLM mineral surface after nanoparticle loading appears to be fully exposed and more porous with irregular shapes in particles diameters of 1-50 microns. FTIR analyses also confirmed dramatic changes in surface functional groups after modification with these nanoparticles. The results showed that the removal efficiency of cephalexin was better at lower pH values. Totally, the removal efficiency increased with increase in adsorbent dosage and contact time and decreased with concentration and temperature increase. The thermodynamics values of ΔG o and ΔH o revealed that the adsorption process was spontaneous and exothermic. In isotherm study, the maximum adsorption capacities (qm) were obtained to be 7.82, 17.09 and 49.26 mg/g for GLM, ZnO/GLM and TiO2/GLM, respectively. Temkin constant (B T ) showed that adsorption of cephalexin from solution was exothermic for all three adsorbents.

Valorization of Poly (ethylene) terephthalate (PET) wastes into magnetic carbon for adsorption of antibiotic from water: Characterization and application

Waste Polyethylene terephthalate (PET) bottles were pyrolyzed in the presence of nitrogen and converted into activated carbon (PETAC) by physical activation in carbon dioxide flow. An ex-situ precipitation and external reduction method were applied for the intercalation of ferromagnetic iron oxides onto the PETAC matrix. The characteristic structural and chemical properties of PETAC and magnetic PETAC (M-PETAC) were studied by Brunauer Emmett Teller (BET) surface area analysis, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FTIR) analysis, Raman spectroscopy, X-Ray Diffraction (XRD) analysis, Energy Dispersive analysis of X-rays (EDAX), Vibrating Sample Magnetometer (VSM), Thermal gravimetric analysis (TGA) and elemental analysis. Characterization results indicated that PETAC exhibited a relatively smooth and microporous texture with a surface area of 659.6 m2g-1 while M-PETAC displayed a rugged morphology with a diminished surface area of 288.8 m2g-1. XRD measurements confirmed the formation of iron oxide nanocrystallites with an average Scherrer crystallite size of 19.2 nm. M-PETAC delivered a quick response to an external magnet and exhibited saturation magnetization value of 35.4 emu g−1. PETAC and M-PETAC were explored as potential adsorbents for the adsorption of a pharmaceutical (cephalexin) from water. Isotherm analysis revealed that M-PETAC exhibited a superior adsorption capacity (71.42 mg g−1) compared to PETAC (21.27 mg g−1). FTIR analysis of the adsorbents after CEX adsorption revealed the role of FeO as the nucleation site for enhanced adsorption of cephalexin by M-PETAC.

Green synthesis of nano-zero-valent iron from Nettle and Thyme leaf extracts and their application for the removal of cephalexin antibiotic from aqueous solutions

ABSTRACTIn this study, the removal of cephalexin (CEX) antibiotic from aqueous solution was examined using a novel green adsorbent without employing any toxic chemicals or capping agents. Nettle and Thyme extracts were used to synthesize novel nano-zero-valent iron (NNZVI and TNZVI) for the adsorption of CEX. The nature and morphology of synthesized adsorbent were characterized by Transmission electron microscopy, scanning electron microscope, X-ray diffraction and Fourier transform infrared spectroscopy spectroscopy. Batch experiments were performed to study the influence of various experimental parameters such as contact time, initial concentration of the CEX, solution pH and adsorbent dosage. The adsorption isotherms of CEX by NNZVI and TNZVI were found to fit well with Freundlich and Langmuir models, respectively. The maximum adsorption capacity of CEX onto NNZVI and TNZVI were observed as 1667 and 1428 mg/g, respectively, based on the Langmuir model. The adsorption trend followed the pseudo-first-order kinetics model and equilibrium could be established in about two hours for both adsorbents. The developed nanoparticles in this study have considerable potential for the removal of CEX and could be considered as a promising adsorbent for the removal of other antibiotics also from aqueous solutions.

Theoretical and experimental study of cephalexin batch adsorption dynamics using walnut shell-based activated carbon

Batch adsorption of cephalexin (CFX) by walnut shell activated carbon is studied both experimentally and mathematically. Firstly, the adsorbent was prepared by chemical activation method in the presence of ZnCl2. Next, the values of adsorbent dosage and pH were optimized. Then, the effect of initial CFX concentration and contact time was studied to evaluate the kinetics and the equilibrium isotherm. It is found that the Freundlich and Toth models provided the best fit to the experimental data. Dynamic characteristics of this process are mathematically modeled. In the developed model, pore diffusivity is estimated according to the experimental results. The model reveals good agreement with experiment. The effective diffusivity of CFX in the walnut shell AC is estimated as 0.47 × 10−9 m2 s−1.

Removal of cephalexin from effluent by activated carbon prepared from alligator weed: Kinetics, isotherms, and thermodynamic analyses

Abstract Low-cost activated carbon was produced from alligator weed by phosphoric acid activation. The cost of production of alligator weed-activated carbon (AWAC) was CN¥ 2.1/kg and the content of activated carbon (AC) in AWAC was 35.33%. AWAC was used as an adsorbent to adsorb cephalexin (CEX) from aqueous solution. Scanning electron microscopy (SEM) analysis of AWAC revealed a highly porous structure with a rough surface. AWAC featured a high surface area of 736.3 m 2 /g and an average pore size of 4.05 nm, which were responsible for its excellent adsorption ability. The maximum CEX adsorption capacity of AWAC was ∼45 mg/g. The Langmuir isotherm ( R 2 = 0.9967) gave the best correlation with the experimental data at 308 K, indicating monolayer adsorption. The kinetic model data on AWAC fit well to the pseudo-second-order kinetic equation, which is considered as the rate-limiting factor. Fourier transform infrared spectroscopy analysis revealed the presence of phosphorus-containing groups and C–H, C–O, and C=C moieties on the surface of AWAC. Following adsorption, the intensity of the spectral peaks of AWAC decreased owing to coverage of the CEX species or reaction with the functional groups of CEX.

Study of Mass Transfer Coefficient of Cephalexin Adsorption onto Walnut Shell-Based Activated Carbon in a Fixed-Bed Column

The adsorption of cephalexin (CFX) onto walnut shell-based activated carbon (AC) was investigated. The mass transfer coefficients were calculated by employing constant wave propagation theory. The effect of different conditions on the mass transfer coefficient was also studied. In addition, three models to predict the mass transfer coefficient were developed. Досліджено адсорбцію цефалексину на активованому вугіллі на основі шкаралупи волоського горіха. З використанням теорії поширення хвиль розраховано коефіцієнти масопередачі. Встановлено вплив різних чинників на коефіцієнт переносу. Розроблено три моделі для прогнозування коефіцієнта масопередачі.

Aqueous phase adsorption of cephalexin by walnut shell-based activated carbon: A fixed-bed column study

The walnut shell was used as a low cost adsorbent to produce activated carbon (AC) for the removal of cephalexin (CFX) from aqueous solution. A fixed-bed column adsorption was carried out using the walnut shell AC. The effect of various parameters like bed height (1.5, 2 and 2.5cm), flow rate (4.5, 6 and 7.5mL/min) and initial CFX concentration (50, 100 and 150mg/L) on the breakthrough characteristics of the adsorption system was investigated at optimum pH 6.5. The highest bed capacity of 211.78mg/g was obtained using 100mg/L inlet drug concentration, 2cm bed height and 4.5mL/min flow rate. Three kinetic models, namely Adam’s–Bohart, Thomas and Yoon–Nelson were applied for analysis of experimental data. The Thomas and Yoon–Nelson models were appropriate for walnut shell AC column design under various conditions. The experimental adsorption capacity values were fitted to the Bangham and intra-particle diffusion models in order to propose adsorption mechanisms. The effect of temperature on the degradation of CFX was also studied.

Improvement of zeolite adsorption capacity for cephalexin by coating with magnetic Fe3O4 nanoparticles

The removal of cephalexin (CEX) from aqueous solution by natural zeolite (NZ) and magnetic Fe3O4 nanoparticles prepared and coated onto natural zeolite (CZ) was investigated. Magnetic Fe3O4 nanoparticles were synthesized by chemical precipitation of a Fe2+ and Fe3+ salts from aqueous solution by ammonia hydroxide solution. SEM images, XRD patterns, XRF spectroscopy, and FTIR spectroscopy were used to characterize the adsorbents. The maximum CEX removal efficiency was 28% and 93% for NZ and CZ, respectively, at optimized condition (pH7, an amount of adsorbent of 0.6g/L, a concentration of CEX of 40mg/L, contact time of 2h, and a temperature of 20°C). The isotherm adsorption of CEX onto both adsorbents was best fitted with Langmuir isotherm equation and the maximum adsorption capacity was 16.1 and 24.9mg/g for NZ and CZ, respectively. The kinetics followed is second order in nature and the intraparticle diffusion was the dominating mechanism. Thermodynamic parameters (∆G°>0 and ∆H°<0) showed the non-spontaneity and exothermic in nature of adsorption process. However, the results showed that the increasing of nitrate, carbonate, and hardness ions decreased the CEX removal efficiency by different trends but their effect can be ranked as nitrate<carbonate<hardness.

Investigation of the Effect of Nanoparticles in the Cephalexin adsorption onto Walnut Shell-based Activated Carbon

Investigation of the Effect of Nanoparticles in the Cephalexin adsorption onto Walnut Shell-based Activated Carbon

Adsorption of cephalexin from aqueous solution using natural zeolite and zeolite coated with manganese oxide nanoparticles

In the present study the adsorption of Cephalexin (CEX) from aqueous solution using natural zeolite (NZ) and zeolite coated with manganese oxide nanoparticles (CZ) were investigated as a function of pH, shaking time, initial CEX concentrations, adsorbent dose, and competitive ions. Scanning electron microscope (SEM) images, X-ray diffraction (XRD) patterns, X-ray fluorescence (XRF) spectroscopy, and Fourier transform infrared (FTIR) spectroscopy were used to characterize the adsorbents. The maximum CEX removal efficiency was 28% and 89% for NZ and CZ, respectively, at pH7. The experimental isotherm data were analyzed by Freundlich, Langmuir, Redlich–Peterson, and Sips models. The results showed that Sips isotherm was the best model and the maximum adsorption capacity went from 16.1mg/g for the NZ to 24.5mg/g for the CZ, for 2g/L adsorbent dose. Comparison of these results with those obtained from previous literature suggested that CZ can be potentially used for CEX removal from aqueous solution. The kinetics of CEX adsorption with different initial concentrations were better fit by the pseudo-second-order model, with higher coefficient of determinations and more closely predicted uptake. Finally, the results showed that the intraparticle diffusion was the dominating mechanism.

Batch adsorption of cephalexin antibiotic from aqueous solution by walnut shell-based activated carbon

The batch adsorption experiments were investigated for the adsorption of cephalexin (CFX) antibiotic on walnut shell activated carbon (AC). The adsorbent was prepared by chemical activation method in the presence of ZnCl2. Several adsorption parameters including the adsorbent dosage, the initial CFX concentration, contact time, temperature, and pH were studied. The adsorption isotherm was analyzed by different isotherm models. It was found that the Freundlich and Toth models provided the best fit for the experimental data for two and three parameter models, respectively. The maximum adsorption capacity was obtained 233.1 mg/g based on the Langmuir model. The kinetic data were well represented by pseudo-second order model. Thermodynamics analysis showed endothermic nature of CFX adsorption on walnut shell AC under examined conditions.

Physicochemical and adsorptive properties of activated carbons from Arundo donax Linn utilizing different iron salts as activating agents

Four kinds of iron salts, ferric chloride (FeCl3), ferrous chloride (FeCl2), ferric citrate (FeC6H5O7) and ferrous oxalate (FeC2O4) were employed as activating agents to prepare activated carbons (AC–FeCl3, AC-FeCl2, AC-FeC6H5O7 and AC-FeC2O4) from Arundo donax Linn (AL). The physicochemical properties of the activated carbons were investigated by N2 sorption/desorption isotherms, XRD, SEM, TEM, FTIR and Boehm's titration. The surface area and micropore volume of AC-FeCl3 and AC-FeCl2 were much higher than those of AC-FeC6H5O7 and AC-FeC2O4. Among the four carbons, AC-FeC6H5O7 displayed the highest external surface area and total pore volume. Boehm's titration results showed that AC-FeCl3 and AC-FeCl2 had more acidic oxygen functionalities than AC-FeC6H5O7 and AC-FeC2O4. Batched sorption studies were carried out to study adsorptive properties of the activated carbons toward cephalexin (CEX). The maximum CEX adsorption capacities of AC-FeCl3 (285.714mg/g) and AC-FeCl2 (238.095mg/g) were higher than those of AC-FeC6H5O7 (227.273mg/g) and AC-FeC2O4 (113.636mg/g), resulting from Lewis acid–base interaction, electrostatic interaction and hydrophobic interaction.

Influence of pH on cephalexin adsorption onto SBA-15 mesoporous silica: Theoretical and experimental study

Cephalexin adsorption from aqueous solutions using SBA-15 mesoporous silica as adsorbent and the influence of pH solution on drug adsorption were studied. In order to have a better knowledge about the way the drug molecules interact with the inorganic matrix, the adsorption process was estimated by applying the computational chemistry software YAeHMOP (Yet Another extended Hückel Molecular Orbital Package). A strong correlation between the theoretical calculations and the experimental results was established, showing that the adsorbate–adsorbent interaction is pH dependent. Calculated cephalexin horizontal adsorption energy was almost 9eV more stable than the one corresponding to vertical adsorption, and also the lowest enthalpy of contact and the maximum adsorption percent were found for the cationic cephalexin–silica system. Cephalexin adsorption through the NH3+ group is 8eV stronger than the molecule adsorption through the COO− group. In agreement with these theoretical predictions, experimental results indicate that the electrostatic attraction between CPX ions and the surface of mesoporous silica is favored at pH values between 2 and 2.56, the maximum being for cephalexin adsorption obtained at pH 2.3.

Modified Silica Matrices for Controlled Release of Cephalexin

SBA-15 type ordered silicas possessing amino groups attached onto their surfaces were prepared by using two different functionalization methodologies. These matrices were used for the cephalexin adsorption from aqueous solution and further kinetic study of its release into physiological solution. The materials were characterized by nitrogen adsorption/ desorption, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), X-Ray photoelectron spectrometry (XPS) and thermo analytical methods (TG/DSC). UV-visible spectroscopy at 262 nm was used for quantitative determination of cephalexin present in liquid media. Results reveal that drug adsorption capacities and the corresponding release profiles are dependent on the number of loaded amino groups and their location, which in turn is determined by the functionalization procedure used. It was concluded that amino post-functionalization could enhance long-term cephalexin delivery in comparison with co-functionalization procedure.

Adsorption of cephalexin onto activated carbons from Albizia lebbeck seed pods by microwave-induced KOH and K2CO3 activations

Microwave technique has been adopted for preparation of two activated carbons from agricultural wastes, Albizia lebbeck seed pods, by KOH and K2CO3 activation. Adsorption mechanisms of a first generation cephalosporin antibiotic, cephalexin (CFX), onto both carbons namely KAC and KCAC have been compared. The yield and surface area of KAC were 22.48% and 1824.88m2/g compared to 26.19% and 1676.61m2/g for KCAC. The analysis of pore structures of prepared carbons showed that KOH activation exhibited higher mesopores content than K2CO3 activating. The experimental isotherm data for adsorption of CFX onto both carbons were analyzed by Langmuir, Freundlich and Temkin isotherms. Langmuir isotherm was the best model giving maximum adsorption capacities of 137.02 and 118.08mg/g on KAC and KCAC, respectively. The kinetic data were well represented by the pseudo-second order model for adsorption onto both carbons. Thermodynamics analysis showed an endothermic CFX adsorption on KAC compared to an exothermic adsorption on KCAC under examined conditions.

Sorption removal of cephalexin by HNO3 and H2O2 oxidized activated carbons

Cephalexin’s traces within pharmaceutical effluents have toxic impact toward ecological and human health. Low-cost activated carbon derived from Trapa natans husk was oxidized with hydrogen peroxide and nitric acid, and tested for their ability to remove cephalexin from aqueous solutions. Oxidization with H2O2 showed negative effect on the cephalexin sorption, whereas HNO3 oxidization improved the adsorption. The cephalexin adsorption isotherms on the native and HNO3 oxidized carbons correlated well with the Freundlich equation while their kinetics followed the pseudo-second order model. The removal of cephalexin by the native and HNO3 oxidized carbons was found to be most favored at low ionic strength and strong acidic conditions. Based on the thermal and FTIR analyses, the interaction mechanisms of the interaction between cephalexin and the carbons were proposed. Electrostatic attraction, hydrophobic interaction and chemical bonding with surface functional groups were demonstrated as primary mechanisms for cephalexin removal. The nitrogen functionalities on the carbon surface were considered to be an important factor affecting the adsorption process.

Functionalized silica matrices for controlled delivery of cephalexin

The surface of SBA-15 ordered mesoporous silica was functionalized with sulphonic and amine functional groups to determine the effect of changes in surface acidity on cephalexin adsorption and subsequent release. Cephalexin (CPX), which belongs to the group of cephalosporins or β-lactam antibiotics, was impregnated on functionalized SBA-15. The functionalized silica materials were characterized by SEM, TGA, FTIR and N2 adsorption, and an in vitro drug delivery test was performed. SEM micrographs showed the packed cylinders correspond to SBA 15 materials. Likewise, N2 adsorption–desorption isotherms demonstrated that the SBA-15 structure was obtained when IV-type isotherms were displayed. The inalterable stabilization of the drug was confirmed by FTIR spectroscopy. For all the samples studied, the delivery profiles exhibit two steps. A fast initial stage was obtained over the first 5 h, followed by a slower one. Regarding this second stage, the time needed to attain a plateau was undoubtedly altered by the surface functionalization.

Preparation and Characterization of Textural and Energetic Parameters of Common and Functionalized SBA-15 Mesoporous Silicas

A set of SBA-15 ordered mesoporous silicas presenting different surface acidities was obtained by organo-functionalization. Amino and sulphonic groups were attached onto the silica surface in order to determine the influence of organo-functionalization with acidic and basic moieties on the adsorption properties of silica. Cephalexin, an antibiotic molecule characterized by its zwitterionic nature, was selected as the adsorbate. The obtained matrices were characterized by scanning electron microscopy, energy dispersive X-ray analysis and nitrogen adsorption isotherms at 77 K. Enthalpies of immersion into water, benzene and cephalexin solutions were measured by immersion calorimetry, and the cephalexin adsorption capacities of the different matrices were also determined. The structure of SBA-15 was conserved in the functionalized samples despite a noticeable reduction in the BET surface area, pore volume and pore size. It was found that the inclusion of amino groups promoted interaction between the adsorben...

Aqueous Phase Adsorption of Cephalexin onto Bentonite and Activated Carbon

The adsorption of cephalexin in aqueous solution has been investigated using bentonite and activated carbon as the adsorbents. Batch kinetics and isotherm studies were carried out to evaluate the effect of contact time, adsorbent dosage, pH, particle size, and temperature. Adsorption equilibrium data were well represented by the Langmuir and Freundlich isotherm models. The adsorption intensity was found to be increased as the aqueous phase pH increased, and had a maximum at pH = 6.1. The pseudo-first order, pseudo-second order, and intraparticle diffusion kinetic models were used to describe the kinetic data. The experimental data fitted very well with the pseudo-second-order kinetic model and also followed the simple external and intraparticle model.