Non-linear Isotherm Models Research Articles

Efficient separation of cerium from rare earth elements and major impurities using low cost manganese ferrites from highly acidic solutions

Sorption of REEs using spinel-ferrite nanoparticles has received great attention in the last decades, because of combining the advantages of iron and manganese metal oxides. Nano-manganese ferrite (MnFe2O4) was successfully synthesized using the co-precipitation method and modified with the addition of zinc to produce (Mn0.8Zn0.2Fe2O4). The synthesized materials were characterized using FTIR, SEM with EDX-mapping, XRD, chemical stability, and surface area. Several process parameters were studied to optimize the efficiency of Ce(III) separation from La(III), Eu(III), Pb(II), and Fe(III) from highly acidic media. The parameters include contact time, solution pH, and metal ion concentration. The sorption process was well fitted to the pseudo-2nd order model, which confirms the chemical nature of the sorption process where equilibrium was achieved after 30 minutes. The pH study's findings demonstrate that Ce(III) was most effectively separated at a very high, acidic pH of 0.5. Both MnFe2O4 and Mn0.8Zn0.2Fe2O4 have high chemical stability in different media where the weight loss was less than 10 %. The correlation coefficient and residual errors analysis confirm that the non-linear extended sips isotherm model more accurately expresses the behavior of the sorption process than the non-linear Freundlich and Langmuir isotherm models. The modified material Mn0.8 Zn0.2Fe2O4 shows higher sorption capacities for all the studied metal ions than MnFe2O4. The maximum sorption capacities of Ce(III), La(III), Eu(III), Pb(II), and Fe(III) in the mixture were 59.2, 6.5, 6.3, 15.4, and 13.7 mg/g, respectively.

Elimination of methylene blue dye from the aqueous solution using waste fig fruit as an activated carbon: a case study of nonlinear adsorption isotherm models and kinetic models

Elimination of methylene blue dye from the aqueous solution using waste fig fruit as an activated carbon: a case study of nonlinear adsorption isotherm models and kinetic models

Modeling of adsorptive treatment of lead (II) ions contaminated effluents using cashew nut shell alkali activated carbon: Batch kinetic, isothermal and thermodynamic studies

The numerical study of the decontamination of lead(II) ions-rich effluent employing activated carbon derived from cashew nut shell was the central focus of this work. Chemical activation with zinc chloride (ZnCl2) was used to produce powdered activated carbon at optimized activation conditions of impregnation ratio (0.531), activation temperature (1083 K) and activation time (63min). The physiochemical properties of raw and activated cashew nut shell were determined using Fourier transform infrared spectroscopy, scanning, X-ray diffractor (XRD), scanning electron microscopy (SEM), and Brunauer-Emmet-Teller (BET) analyses. Batch adsorption experiments were performed at varied process conditions of temperature (303–323) K, contact time (5–80min), and initial lead(II) ion concentrations (100–400 mg.L−1). The adsorption behavior of the batch–type operation was mathematically described in the form of non-linear parabolic partial differential equations (PDE’S) incorporating film, pore and surface diffusion mechanisms. The batch mathematical model was solved by implementing a custom MATLAB program-OkiyNwabannebatch and calibrated to predict the desired response (percentage removal) using measured adsorption data. The equilibrium adsorption, kinetics and thermodynamics of lead(II) ions adsorption onto activated cashew nut shell were also assessed using nonlinear isotherm, kinetic and thermodynamic models. Sensitivity analysis unveiled that temperature with sensitivity value of 37.31 % had a predominant effect on the model performance. The simulated equilibrium data was well explicated by the Freundlich model for lead(II) ions adsorption onto activated cashew nut shell. The pseudo-second order kinetic model best reproduced the simulated adsorption data for lead(II) ions uptake by cashew nut shell adsorbent. Likewise, the kinetic data followed Boyd model, indicating that the adsorption process is controlled by external (film) diffusion for the uptake of lead(II) ions by alkali activated cashew nut shell. Thermodynamic analysis using the Gibbs and Van’t Hoff’s models indicated that lead(II) ions adsorption by modified cashew nut shell is spontaneous and exothermic. The physical nature of the adsorption process was elucidated from the low values of the isosteric heats of adsorption (ΔHX) evaluated (<80 kJ mol−1). This study showed that zinc chloride activated cashew nut shell has good potential to be used as a cost-effective and efficient adsorbent for the uptake of lead(II) ions from aqueous solution.

Facile preparation of multifunctional cellulose nanocrystals from coffee residue via hydrothermal technique: Prolific roles on the water purification, antibacterial and antifungal applications

In this work, the facile preparation of coffee residue (CR)-derived multifunctional cellulose nanocrystals (CNCs) via hydrothermal technique has been successfully attempted. The morphological structure, functionality, crystalline pattern, surface chemistry, elemental content and surface charge were evaluated. The adsorptive property was assessed using both anionic and cationic aqueous pollutants, chlorpyrifos and methylene blue (MB), and simulated by the non-linear isotherm models and kinetic equations. Its unique antibacterial and antifungal functions were tested against both gram-negative/positive bacterial and fungal species. The particle length and diameter, aspect ratio, crystallinity index, sulfate group content and zeta potential of this newly prepared rod-shaped CNCs were identified to be 432.39 nm, 23.57 nm, 18.34, 75.0 %, 0.21 mmol/g and −32.7 mV, respectively. CR-CNCs recorded an outstanding adsorptive feature for both MB and chlorpyrifos, with the monolayer adsorption capacities of 403.02 mg/g and 159.75 mg/g, respectively. The adsorptive uptakes could be effectively preserved via solvent regeneration technique, even after 5 adsorption-desorption runs. Excellent inhibition efficiencies against both gram-negative/gram-positive bacteria, and fungal species have been detected, with the growth-inhibition zones ranging from 10.9 to 26.7 mm. The novel protective roles of the newly prepared CR-CNCs against both biological and water contaminants have been well-elucidated.

Utilization of organic waste from Chinar leaves as sustainable and eco-friendly adsorbent for fluoride removal.

Due to concerns about high water fluoride concentrations and their detrimental consequences on health, particularly dental and skeletal fluorosis, dependable and cost-effective defluoridation techniques are needed. Chinar leaves (Platanus orientalis), a common waste, might be utilized for the production of activated carbon. For Chinar leaf activated carbon (CLAC) manufacturing, two pre-pyrolysis chemical modification procedures were used: acidic HCl (H-activation) and alkaline NaOH (OH-activation). The success of fluoride removal suggests further research and implementation in locations with fluoride-related water quality issues. This study examines how CLAC dosage, fluoride concentration, temperature, pH, and contact exposure effect defluoridation efficiency. The pseudo-second-order non-linear kinetic model and Freundlich non-linear isotherm model with R2 = 0.99 fit the data, resulting in a peak adsorption capacity of 30.3mg/g for 0.3g CLAC. In the present work, the adsorption mechanism was regulated by more than intraparticle diffusion. Adsorption occurred spontaneously as exothermic monolayer chemisorption, according to thermodynamic studies. Adsorbent activated with HCl (H-activated) showed promising results, with 73% F- removal efficiency for OH-activated and 91% for H-activated CLAC.

Alginate-Based Hydrogel Bead Reinforced with Montmorillonite Clay and Bacterial Cellulose-Activated Carbon as an Effective Adsorbent for Removing Dye from Aqueous Solution.

According to environmental concerns related to water pollution, this study aims to develop a novel hydrogel bead as a biocompatible and efficient adsorbent by integrating bacterial cellulose-activated carbon (BCAC) and montmorillonite (MT) in alginate hydrogel (ALG). The ionotropic gelation method was applied to the fabrication of BCAC/MT/ALG hydrogel beads. The BCAC/MT/ALG hydrogel bead exhibited significantly higher tensile strength, Young's modulus, and thermal stability, with ~1.4 times higher adsorption uptake of methylene blue (MB) from aqueous solution as compared to the pristine ALG bead. The textural properties, including specific surface area and porosity, were beneficial to accommodate the size of cationic MB as the target molecule. This resulted in a remarkable MB adsorption uptake of 678.2 mg/g at pH 7 and 30 °C. The adsorption isotherm showed the best fit for the nonlinear Redlich-Peterson isotherm model. Experimental adsorption data were well-described by the pseudo-second order kinetic model, with R2 values reaching 0.997. In addition, the adsorbent bead demonstrated easy regeneration with high reusability with approximately 75% of MB removal after being used for six cycles. Therefore, BCAC/MT/ALG bead represents an eco-friendly, cost-effective, and highly efficient adsorbent for MB removal from water and could potentially be used for removal of a wide range of cationic dye pollutants from wastewater.

High-quality mesoporous adsorbent derived from pomegranate pomace for efficient removal of azo dye from textile wastewater: Influencing factors, reusability, and mechanism studies

The solid waste from the processing of pomegranate (Punica granatum L.) juice, known as pomegranate pomace, was utilized as an economical and readily available precursor to produce high-quality activated carbon (AC). The AC was synthesized using a low-cost method at a carbonization temperature of 600 °C, employing a 1:1 impregnation ratio (precursor/H3PO4), and activating for 1 h. Various characterization techniques, including SEM imaging, XRD analysis, FT-IR analysis, BET surface area analysis with pore size determination, and other physicochemical assessments, were conducted on the produced AC. To assess its efficacy in treating textile wastewater, Basic Yellow 28 (BY 28) dye was selected as a representative pollutant. The results displayed a mesoporous structure in the produced AC with a mesopore content of 78.82 %. Notably, it exhibited a high BET surface area of 1089.08 m2/g and a total pore volume of 1 cm3/g. The Langmuir non-linear isotherm model emerged as the most fitting for explaining the adsorption equilibrium data, revealing a substantial monolayer adsorption capacity of 659.13 mg/g at 20 °C. The experimental data fit into a pseudo-second-order kinetic model, where the rate-determining step was found to be intra-particle diffusion. Thermodynamic analysis revealed that the adsorption of BY 28 dye onto the produced AC was an exothermic process. The produced AC exhibited high stability, as demonstrated in desorption studies, maintaining effectiveness through multiple uses. These results signify the potential of using pomegranate pomace, an environmentally problematic waste, as a novel precursor for producing sustainable and cost-effective AC.

Adsorption and photocatalytic degradation of 2,4-dicholrophenol using surgical mask derived SMAC-Fe2O3 composite; adsorption isotherms, kinetics, thermodynamics.

Hybrid material of surgical mask activated carbon (SMAC) and Fe2O3 (SMAC-Fe2O3) composite was prepared by simple co-precipitation method and used as potential material for the remediation of 2,4-dicholrophenol (2,4-DCP). The XRD patterns exhibited the presence of SMAC and Fe2O3, FTIR spectrum showed the FeO-carbon stretching at the wavenumber from 400 to 550cm-1. UV-Vis DRS results showed the band gap was 1.97eV and 2.05eV for SMAC-Fe2O3 and Fe2O3, respectively. The SEM images revealed that the Fe2O3 doped onto the fiber morphology of SMAC. The outcomes of the BET examination exhibited a surface area of 195 m2/g and a pore volume of 0.2062 cm3/g for the SMAC/Fe2O3 composite. The batch mode study shows the maximum adsorption and photocatalytic degradation efficacies which were 97% and 78%, respectively. The experimental data was studied with both linear and nonlinear adsorption isotherm and kinetics models. The nonlinear Langmuir isotherm and pseudo-second-order kinetics (PSOK) models have well fit compared with other models. The Langmuir maximum adsorption capacity (qmax) was found 161.60mg/g. Thermodynamic analysis shows that the 2,4-DCP adsorption onto SMAC-Fe2O3 was a spontaneous and exothermic process. The PSOK assumes that the adsorption process was chemisorption. The photocatalytic degradation rate constant of 2,4-DCP was calculated using pseudo-first-order kinetics (PFOK) and the rate constant for SMAC-Fe2O3 and Fe2O3 were 0.859 × 10-2min-1 and 0.616 × 10-2min-1, correspondingly. In addition, the obtained composite exhibited good reusability after a few cycles. These results confirmed that SMAC-Fe2O3 composite is an effective adsorbent and photocatalyst for removing 2,4-DCP pollutants.

Amino-functionalization of PVA/TiO2-CeO2 nanohybrid adsorbent for the removal of selenium ions from aqueous solutions: Equilibrium and kinetics studies

ABSTRACT In this study, a hybrid nanoadsorbent (HnA), (PVA/TiO2-CeO2), was synthesized and amino-functionalized by 3-aminopropyltriethoxysilane (APTES) to produce AHnA, for use in an advanced selenium adsorption study focusing on nonlinear equilibrium and kinetics models. AHnA was characterized using XRD, FTIR spectroscopy, SEM, and EDX elemental analyses, as well as BET-BJH techniques. According to the FTIR results, APTES has successfully cross-linked the PVA chain and introduced amine groups on the surface. Moreover, the modification resulted in an increase in the total pore volume from 0.0061 cm3/g in HnA to 0.021 cm3/g in AHnA. Several adsorption experiments were conducted to determine the impact of varying contact times within a pH range of 1 to 8 and concentrations ranging from 5 to 200 mg/L, using a One-Variable-At-a-Time (OVAT) procedure. Accordingly, a dosage of 2 g/L of modified nanocomposite exhibits optimal performance for removing selenium from a 20 mg/L solution at an acidic pH of 3 during 300 minutes of contact with selenium ions, while conforming to a pseudo-second-order kinetic model. The assessment of various nonlinear isotherm models for analyzing equilibrium data revealed that the experimental data of selenium adsorption conformed to a generalized isotherm, showing a maximum monolayer adsorption capacity of 17.643 mg/g.

Cerium-based metal-organic-frameworks with ligand tuning of the microstructures for fluoride adsorption: linear and nonlinear kinetic and isotherm adsorption models.

We present the synthesis and characterisation of three Ce-based metal-organic frameworks (Ce-MOFs) using fumaric acid (Fu), terephthalic acid (BDC), and trimesic acid (H3BTC) as linkers. The use of different linkers influenced the size of the MOF particles, surface area, crystallinity, and microporous structure. The successful implementation of Ce-Fu, Ce-BDC, and Ce-H3BTC MOFs for fluoride ion removal from wastewater was carried out, in which Ce-Fu MOFs exhibited a maximum adsorption capacity (AC) of 64.2 mg g-1. The study also reveals that the use of ultrasound as a mediator for adsorption study over conventional method gives rapid adsorption rate, in which 85% of the fluoride uptake took place just in 10 min and achieved maximum AC in 30 min. The kinetics data were most accurately explained by the pseudo-second-order model (PSO). The existence of co-ions such as NO3-, Cl-, HCO3-, SO42-, Br-, CO32-, and PO43- has a substantial effect on fluoride removal. The mechanism between the fluoride ions and the MOF surface took place via the electrostatic force and the ion exchange process, confirmed using X-ray photoelectron spectroscopy (XPS) and delsa nano. The material is sustained its relatively higher F- ions removal efficiency up to the five cycles. This research might help in the development of novel microporous Ce-based MOFs since it possesses a highly stable crystalline structure in water, suggesting a promising role in aqueous applications.

Removal of Fe and Mn from Co leach solutions by adsorption on activated carbon based on post-consumer polyethylene terephthalate (PET) - Mechanism insights through linear and nonlinear isotherm and kinetic models

ABSTRACT The removal of Fe2+ and Mn2+ from cobalt sulfate-saturated solutions is frequently problematic for Cu-Co hydrometallurgical process performance. Among the applied and developed methods for the removal of these metals, adsorption has drawn less attention. This study investigates on the removal of Fe2+ and Mn2+ in industrial cobalt solutions known as raffinates by adsorption on activated carbon prepared from post-consumer polyethylene terephthalate (PET). The adsorption operating conditions were studied in synthetic solutions and industrial solutions. The Langmuir, Freundlich, and Temkin isotherms were then used to fit the adsorption data, while the pseudo-first-order (PFO), pseudo-second-order (PSO), and Elovich models were used to describe the kinetics. Linear and nonlinear kinetic and isotherm models were studied and compared. Furthermore, intraparticle diffusion (IPD) models were used to study the transfer mass mechanism. The results show that Fe2+ and Mn2+ are removed from Co solutions with the efficiencies of 62.14 and 68.43, respectively. The Langmuir model fits the Fe2+ and Mn2+ adsorption data better, indicating that chemisorption is preferred over physisorption, whereas the Freundlich model fits the Co2+ adsorption data better, indicating that physisorption is preferred over chemisorption. The PFO model describes well the kinetic behavior of Fe2+ and Mn2+, whereas the Elovich model describes better the kinetic behavior of Co2+. According to the IPD model, the step that limits the adsorption of Fe2+, Mn2+, and Co2+ is essentially diffusion through the activated carbon pores. The reported experimental results will highlight the use of activated carbon in the removal of Fe2+ and Mn2+ in Cu and Co hydrometallurgy.

Assessment of activated carbon/alginate for the concurrent removal efficiency of paracetamol and caffeine from wastewater in their binary solutions

The increasing amount of pharmaceutical chemicals in wastewater is a concern for both public health and the environment. This research investigates the effectiveness of a new composite material made of alginate-activated carbon in removing caffeine and paracetamol from wastewater simultaneously. The composite material, produced using a simple technique, demonstrates excellent removal rates and exceptional adsorption properties for both medicinal chemicals. The structural stability and integrity of the composite are confirmed through comprehensive characterization methods including scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction, energy dispersive X-ray (EDX), and BET surface area analysis. The study uses batch adsorption experiments to assess the impact of various factors, such as pH, initial concentration, and contact time, on the efficiency of caffeine and paracetamol removal. The highest values for the adsorption process were 89.63% for Paracetamol and 97.32% for Caffeine, achieved under optimal experimental conditions (pH 7, 0.1 g dose of adsorbent at elevated temperature). Additionally, Kinetic studies and thermodynamic parameters such as ΔS°, ΔGº, and ΔH° were calculated, indicating that the adsorption process was endothermic and spontaneous for paracetamol, and exothermic and non-spontaneous for caffeine. Seven non-linear equilibrium isotherm models were utilized to fit the experimental data for paracetamol and caffeine at pH 7 showing maximum adsorption capacities (qmax) of 606.80 and 725.05 mg/g for Paracetamol and Caffeine, respectively with a high regression coefficient (R2) of 0.99 using alginate-activated carbon as an adsorbent, The results demonstrate the potential of alginate-activated carbon as an effective adsorbent for the simultaneous removal of various pharmaceutical pollutants, highlighting the synergistic adsorption effects of the composite material. The study also examines the safety of the composite material, particularly in the context of potential medical applications. The study emphasizes the potential for sustainable and repeated use of the activated carbon/alginate composite, demonstrating that it maintains both its structural integrity and adsorption effectiveness after multiple cycles of use. This study evaluated the suitability of the suggested analytical method using BAGI, a metric with a unique formula. The BAGI is a complementary tool to GAPI, Complex GAPI, AGREE, AGREE prep, and ESA. A major focus is on the practical elements of white analytical chemistry centered around “blue”.

Adsorption isotherm, kinetic and thermodynamic studies for adsorption of fluoride on waste marble powder

Economically viable, efficient waste marble powder (WMP) for fluoride removal has been studied. A batch adsorption study has been carried out concerning contact time, initial concentration, adsorbent dosage, pH, and temperature. After using a batch adsorption mode, 97.13 % removal efficiency was observed with an adsorption capacity of 1.166 mg/g at the initial fluoride concentration of 6 mg/L, solution pH of 6, adsorbent dosage of 500 mg, temperature of 35 °C, and contact time of 60 min. According to kinetics studies, the experimental adsorption data fit well in a nonlinear pseudo-second order with the adjusted-R2 value 0.999, and the nonlinear Langmuir isotherm model fitted best with the adjusted-R2 value 0.988. The separation factor (RL) values were within the range of 0.178 - 0.086, suggesting a satisfactory uptake of fluoride ions. Thermodynamic analysis showed that the adsorption process was endothermic, and negative values of Gibbs free energy change (∆Go) indicated spontaneous fluoride adsorption. In contrast, a positive value of entropy change (∆So= 65.26) indicated arbitrary behaviour at the interface between the solid and the solution. Fluoride removal from aqueous solution was also studied using a continuous fixed-bed column. The Yoon-Nelson model, with a higher adjusted-R2 value of 0.9906, described the dynamics of the fluoride adsorption process better than the Adams-Bohart model because it had better predictions for the breakthrough curve. According to the regeneration analysis, 52 % of the adsorption rate with an adsorption capacity of 0.604 mg/g could be achieved even after five cycles of WMP regeneration.

ACTIVATED CARBON PREPARED FROM SOFTWOOD LIGNOCELLULOSIC BIOMASS – OPUNTIA FICUS INDICA CORDS TO REMOVE AN ANIONIC DYE

In this work, lignocellulosic biomass, namely, Opuntia ficus indica cords (OFIC), was selected as a renewable resource for the production of activated carbon. The preparation conditions of chemically activated carbon (AC) samples were the following: activation temperature – 600 °C, heating rate – 10 °C min-1, activation time – 60 min, and OFIC/H3PO4 impregnation ratio – 1/2. The properties of OFIC and activated carbon were determined by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Boehm’s method, and pHzpc. AC showed heterogeneous surface and acidic characteristics with a pHZPC of 2.61. OFIC and AC were used as adsorbents to remove the anionic dye Red Bemacid (RB) from aqueous solutions. OFIC was used as a reference for comparison with the prepared AC. The results showed that the experimental data fitted very well with the pseudo-second-order nonlinear model of both adsorbents, with 120 min as equilibrium time and the nonlinear isotherm models of three parameters (Sips and Redlich-Peterson isotherms) were selected as the best fitting ones. The thermodynamic parameters indicated that the adsorption process was spontaneous and endothermic for the AC/RB dye system.

Adaptive structural modification of Zr-based MOF-808 via solvent and ligand engineering for enhanced fluoride ion adsorption efficiency

The rapid development of industries such as new energy and photovoltaic has led to the generation of a large amount of industrial fluorine wastewater, posing serious threats to water environment and human health. To address this issue, MOF-808 adsorbent was synthesized by controlling the synthesis conditions and modifying the ligand structure. Batch adsorption experiments were conducted by varying experimental conditions, including type of adsorbent, pH, wastewater concentration, adsorption time, temperature, and interfering anions. The adsorption behavior of MOF-808-AA towards fluoride ions was well fitted by the Elovich non-linear kinetic model, as well as the Freundlich and Temkin non-linear isotherm models, indicating that the adsorption behavior was influenced by multiple mechanisms other than just intraparticle diffusion. Thermodynamic results suggested a spontaneous exothermic monolayer chemical adsorption process. Under the conditions of pH 6.0 and T = 298 K, MOF-808-AA exhibited a maximum adsorption capacity of 84.65 mg/g for fluoride ions. Characterization techniques, as well as quantum chemical analysis was employed to analyze the adsorption behavior and predict the reaction sites. The potential mechanism can be summarized as the formation of new bonds between MOF-808-AA and the adsorbed fluoride ions, as well as the weak intermolecular interactions such as hydrogen bonding and vdW forces. Furthermore, MOF-808-AA demonstrated satisfactory reusability and excellent chemical stability during the cyclic process. These findings suggest the potential application of MOF-808-AA for removing fluoride ions from wastewater.

Cellulose-based Co[sbnd]Fe LDH composite as a nano-adsorbent for sulfamethoxazole and cefixime residues: Evaluation of performance, green metrics and cytotoxicity

The increase in antibiotic residues poses a serious threat to ecological and aquatic environments, necessitating the development of cost-effective, convenient, and recyclable adsorbents. In our study, we used cellulose-based layered double hydroxide (LDH) as an efficient adsorbent and nanocarrier for both sulfamethoxazole (SMX) and cefixime (CFX) residues due to their biodegradability and biocompatibility. Chemical processes are measured according to green chemistry metrics to identify which features adhere to the principles. A GREEnness Assessment (ESA), Analytical GREEnness Preparation (AGREEprep), and Analytical Eco-Scale Assessments (ESA) were used to assess the suitability of the proposed analytical method. We extensively analyzed the synthesized CoFe LDH/cellulose before and after the adsorption processes using XRD, FTIR, and SEM. We investigated the factors affecting the adsorption process, such as pH, adsorbent dose, concentrations of SMX and CFX and time. We studied six nonlinear adsorption isotherm models at pH 5 using CoFe LDH, which showed maximum adsorption capacities (qmax) of 272.13 mg/g for SMX and 208.00 mg/g for CFX. Kinetic studies were also conducted. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was performed on Vero cells in direct contact with LDH nanocomposites to evaluate the cytotoxicity and side effects of cellulose-based CoFe LDH. The cellulose-based CoFe LDH nanocomposite demonstrated excellent cytocompatibility and less cytotoxic effects on the tested cell line. These results validate the potential use of these unique LDH-based cellulose cytocompatible biomaterials for water treatment applications. The cost of the prepared adsorbents was investigated.

Remediation of acetamiprid pesticide from contaminated water by antibacterial biosorbent based on carboxymethyl tragacanth-grafted-poly(3-aminophenol) decorated with ZnO@Fe3O4

Pesticides can have harmful impacts on the environment and living organisms. Thus, removing them from polluted water is crucial. In this study, a bionanocomposite of carboxymethyl tragacanth-grafted-poly(3-aminophenol)/zinc oxide@iron oxide (CMT-g-P3AP/ZnO@Fe3O4) synthesized by in situ copolymerization as an efficient adsorbent to eliminate the acetamiprid pesticide from polluted water. The CMT-g-P3AP/ZnO@Fe3O4 magnetic nanocomposite was analyzed utilizing various techniques including FTIR, EDX, FESEM, XRD, BET, CHNSO, and TGA. The results displayed that the resulting nanocomposite with maximum adsorption capacity (Qmax) successfully removed the acetamiprid pesticide from polluted water under optimal conditions such as pH of 7.00, 5.00 mg of adsorbent, 20.0 min duration, and 400 mg/L acetamiprid concentration. According to the linear Langmuir isotherm, the Qmax of the biosorbent was 833 mg/g. The experimental adsorption data fitted well with Temkin's nonlinear isotherm model. The adsorption kinetic data were closely related to the Weber-Morris intraparticle diffusion nonlinear model. After three repetitive cycles, CMT-g-P3AP/ZnO@Fe3O4 can be outstandingly renewed and recycled without significant reduction in its adsorption efficacy, as evidenced by the adsorption-desorption experiments. In addition, the CMT-g-P3AP/ZnO@Fe3O4 displayed the good antibacterial activity against E. coli and S. aureus.

Single and multicomponent adsorption of amoxicillin, ciprofloxacin, and sulfamethoxazole on chitosan-carbon nanotubes hydrogel beads from aqueous solutions: Kinetics, isotherms, and thermodynamic parameters

The removal of antibiotics in water receiving bodies is an integral part in eradicating antimicrobial resistance which has become a major threat to public health. Solid-liquid adsorption has demonstrated to be an effective technique in the removal of antibiotics from aqueous environments. Herein, chitosan-carbon nanotube (chitosan-CNT) hydrogel beads were synthesised for the adsorption of amoxicillin (AMX), ciprofloxacin (CIP) and sulfamethoxazole (SMX) from aqueous solution. Adsorption kinetics, isotherms and thermodynamic parameters were systematically investigated at a solution pH of 7. Single adsorption kinetics findings suggest that experimental data for AMX, CIP and SMX was better fitted by the nonlinear pseudo-first order model with calculated maximum adsorption capacities of 23.1 mg.g−1, 23.7 mg.g−1 and 25.17 mg.g−1, respectively. Moreover, findings from the Weber-Morris kinetic model suggest that multiple processes were limiting the overall adsorption rate of AMX, CIP and SMX on chitosan-CNT. Adsorption isotherm results indicated that single adsorption experimental data was better fitted by the nonlinear Freundlich isotherm model, while binary and ternary system experimental data were better fitted by the nonlinear competitive extended Sips adsorption isotherm models. Moreover, results for binary and ternary adsorption showed that multicomponent adsorption systems exhibited both antagonistic and synergistic adsorption of AMX, CIP and SMX. From the thermodynamics fundings, it was evident that the adsorption of AMX, CIP and SMX from solution is an endothermic process governed by both physical and chemical adsorption mechanisms. Based on the findings of the current study, it was concluded that chitosan-CNT has potential as a green technology for the removal of antibiotics from solution.

Activated carbon from single use surgical mask as an efficient adsorbent for 4-nitrophenol and 2,4-dicholorophenol from aqueous solution: adsorption kinetics, isotherms and thermodynamic study

ABSTRACT The activated carbon was prepared from single use surgical masks (SUSM) by hydrothermal method, resulting in a synthesised material termed SMAC. The physico-chemical properties of SMAC were analysed. The XRD pattern showed the amorphous nature, the FT-IR spectrum displayed the characteristic peaks of polypropylene, zeta potential analysis revealed the negative surface charge, SEM analysis showed the fibre morphology and XPS results confirmed the presence of oxygen, carbon and sulphur compounds. The adsorption properties were analysed using 4-nitrophenol (4-NP) and 2,4-dicholorophenol (2,4-DCP) from aqueous solution. The linear and nonlinear pseudo-first order, pseudo-second order, Elovich, intraparticle diffusion, external diffusion models and adsorption isotherms with linear and nonlinear Langmuir, Freundlich, and Temkin models were examined using adsorption data. The nonlinear kinetics and isotherm models have a better fit compared with linear models. The results were better fitted with pseudo-second order (0.9987 & 0.9962) and Elovich model (0.9964 & 0.9962) and described the adsorption process was leading by chemisorption fairly than physisorption. The Langmuir maximum adsorption capacity of SMAC for 4-NP and 2,4-DCP was 89.46 and 141.88 mg/g, respectively. Further, the thermodynamic study explained that the adsorption process of 4-NP and 2,4-DCP onto SMAC is an endothermic reaction. Among two regenerating agents (HCl & NaOH), 0.1 M NaOH was favoured for desorption of 4-NP (46%) and 2,4-DCP (40%) from SMAC. The recyclability studies showed that 67% and 64% of 4-NP and 2,4-DCP were removed after third cycle, respectively. The results conclude that the SMAC was an efficient adsorbent for phenols and economically viable.

Cost-effective eggshell-modified LDH composite for caffeine adsorption, cytotoxicity and antimicrobial activity: exploring the synergy and economic viability in search processes.

The rise of pharmaceutical residues poses a serious threat to ecological and aquatic environments, necessitating the development of cost-effective, convenient, and recyclable adsorbents. Given the high global consumption of eggs, a significant amount of waste eggshell is produced. The techniques outlined here aim to manage eggshell waste by transforming it into highly valuable products, addressing the issue of eggshell waste in communities and industries. This approach supports the concept of zero-waste operations to create value-added goods, contributing to sustainable development. In the future, this method of waste management and material recycling may be adopted as an alternative. CaO-based ZnFe-layered double hydroxide (LDH) is identified as an efficient adsorbent for caffeine (COF) residues due to its biodegradability and biocompatibility. We extensively analyzed the synthesized CaO, ZnFe-LDH, and CaO/ZnFe-LDH composites before the adsorption processes using FT-IR, XRD, SEM, EDX, BET surface area, PZC, TGA/DTG, and after the adsorption processes using FT-IR. We investigated factors affecting the adsorption process, such as pH, adsorbent dose, COF concentrations, and time. Six non-linear adsorption isotherm models were studied at pH 7 for the composite and pH 9 for LDH, showing maximum adsorption capacities (q max) of 152.35 mg g-1 for LDH and 194.87 mg g-1 for CaO/ZnFe-LDH. Kinetic studies were also conducted. Interestingly, the MTT assay conducted on WI-38 cells revealed minimal toxicity, with most tests indicating cell viability above 60%. The synthesized CaO, ZnFe-LDH, and CaO/ZnFe-LDH composite exhibit robust antimicrobial properties against two pathogens, including Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (MRSA). The MIC values for the synthesized materials range from 0.87 to 7 µg mL-1, varying with the microbial species. Two green metrics were applied: the analytical Eco-scale and the Analytical GREEnness Calculator (AGREE).