Showing papers on "Langmuir published in 2014"
TL;DR: The real wastewater experiment, the regeneration study and the comparative cost analysis showed that the RL-GO composites could be a cost-effective and promising sorbent for MB wastewater treatment owing to its high efficiency and excellent reusability.
509 citations
TL;DR: This article examined the adsorption of trace metals (Cd, Co, Cr, Ni and Pb) to both virgin and beached (aged) pellets under estuarine conditions in order to better understand the role of plastic materials on the transport and behaviour of metals from river to ocean.
433 citations
TL;DR: In this paper, a batch of experiments were conducted to test the ability of activated carbon for the removal of lead, cadmium, nickel, chromium and zinc from water.
406 citations
TL;DR: A nano-composite cation exchanger sodium dodecyl sulfate acrylamide Zr(IV) selenite (SDS-AZS) was developed by sol-gel method.
404 citations
TL;DR: In this paper, a metal-organic framework based on copper-benzenetricarboxylates was applied to the adsorption of methylene blue (MB) from aqueous solution.
352 citations
TL;DR: Nanoscale zero valent iron (NZVI) has high adsorption capacity of As(III) and As(V), but it is limited in practical use due to its small particle size and aggregation effect, so reduce graphite oxide (RGO) has been used as a support because of its high surface area.
326 citations
TL;DR: In this paper, a pomegranate peel was converted into activated carbon using microwave induced and KOH activation techniques and the prepared activated carbon (PPAC) was characterized using FTIR, TGA, SEM, and nitrogen-adsorption surface area (BET).
286 citations
TL;DR: In this article, a cellulose nanocrystals (CNCs) prepared from cellulose fiber via sulfuric acid hydrolysis was used as an adsorbent for the removal of methylene blue (MB) from aqueous solution.
Abstract: Cellulose nanocrystals (CNCs) prepared from cellulose fibre via sulfuric acid hydrolysis was used as an adsorbent for the removal of methylene blue (MB) from aqueous solution. The effects of pH, adsorbent dosage, temperature, ionic strength, initial dye concentration were studied to optimize the conditions for the maximum adsorption of dye. Adsorption equilibrium data was fitted to both Langmuir and Freundlich isotherm models, where the Langmuir model better described the adsorption process. The maximum adsorption capacity was 118 mg dye/g CNC at 25 °C and pH 9. Calculated thermodynamic parameters, such as free energy change (ΔG = −20.8 kJ/mol), enthalpy change (ΔH = −3.45 kJ/mol), and entropy change (ΔS = 0.58 kJ/mol K) indicates that MB adsorption on CNCs is a spontaneous exothermic process. Tunability of the adsorption capacity by surface modification of CNCs was shown by oxidizing the primary hydroxyl groups on the CNC surface with TEMPO reagent and the adsorption capacity was increased from 118 to 769 mg dye/g CNC.
271 citations
TL;DR: Analysis of experimental adsorption data to various kinetic models such as pseudo-first and second order, Elovich and intraparticle diffusion models show the applicability of the second-order equation model.
267 citations
TL;DR: Graphene oxide/chitosan/silica fibers were prepared by a wet spinning technique as discussed by the authors, and the results indicated that the equilibrium data were perfectly represented by the Langmuir isotherm.
264 citations
TL;DR: In this paper, a novel agricultural waste, rambutan (Nephelium lappaceum) peel was used as the precursor for preparation of activated carbon by chemical assisted KOH activation.
TL;DR: In this article, a corrosion inhibitor was synthesized and its inhibiting action on the corrosion of mild steel X52 in 1M hydrochloric acid and 1M sulfuric acid was examined by different corrosion methods, such as weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS).
TL;DR: In this paper, Mg-Al and Zn-Al layered double hydroxides (LDHs) were synthesized by co-precipitation method at a constant pH of 9-10.
TL;DR: By utilizing the synergistic effect of poly-dopamine (PD) with functional groups and graphene oxide (GO) with a high surface area, a series of sub-nano thick PD layer coated GO (PD/GO) composites were fabricated by a well-controlled self-polymerization of dopamine via catechol chemistry and used for effectively decontaminating wastewater.
Abstract: By utilizing the synergistic effect of poly-dopamine (PD) with functional groups and graphene oxide (GO) with a high surface area, a series of sub-nano thick PD layer coated GO (PD/GO) composites were fabricated by a well-controlled self-polymerization of dopamine via catechol chemistry and used for effectively decontaminating wastewater. The obtained PD/GO could selectively adsorb the dyes containing an Eschenmoser structure and showed an extremely high adsorption capacity up to 2.1 g g−1, which represents the highest value among dye adsorptions reported so far. The adsorption mechanism was investigated by FTIR analysis, solution pH effect, and some control experiments. It was concluded that the adsorption process was based on the Eschenmoser salt assisted 1,4-Michael addition reaction between the ortho position of the catechol phenolic hydroxyl group of PD and Eschenmoser groups in the dyes. The adsorption isotherms were explored according to the Langmuir and Freundlich models respectively, and matched well with the Langmuir model. The thermodynamic parameters (ΔH, ΔG, ΔS, and E) were also calculated, which suggested an exothermic and spontaneous adsorption process. In addition, PD/GO exhibited an improved adsorption capacity for heavy metal ions (53.6 mg g−1 for Pb2+, 24.4 mg g−1 for Cu2+, 33.3 mg g−1 for Cd2+, and 15.2 mg g−1 for Hg2+, respectively) than pure PD and GO. Our results indicate the effectiveness of the synergistic effect of individual components on designing new functional composites with high performance.
TL;DR: In this paper, the application of a straw ash from barley as a novel bio-adsorbent for the removal of several heavy metals: Ni(II), Cd(II, Cu(II) and Co(II).
TL;DR: In this paper, the adsorption of lead (Pb 2+ ) onto activated carbon (AC) originating from cow bone, chemically modified with HNO 3, was investigated.
TL;DR: In this paper, the biosorption of PbII ions onto peanut shells from an aqueous solution was studied in a batch system as a function of temperature, pH of the solution, contact time, initial concentration of pb(II) ions, and peanut shell concentration.
Abstract: In this study, the biosorption of Pb(II) ions onto peanut shells from an aqueous solution was studied in a batch system as a function of temperature, pH of the solution, contact time, initial concentration of Pb(II) ions, and peanut shell concentration. It was determined that the biosorption capacity of the peanut shells decreased as the temperature was increased. Several kinetic models were used to determine the biosorption mechanism. It was determined that the biosorption system obeyed the pseudo-second-order kinetic model by taking into account the correlation coefficient value. Calculated activation energy value (Ea) was 33 kJ/mol and indicates that physical biosorption mechanisms occurred. This value indicated that physical biosorption mechanisms occurred. The linear forms of the Freundlich and Langmuir isotherms were applied to the biosorption data, and it was concluded that the Langmuir isotherm gave a better fit than the Freundlich model based on the values of the correlation coefficients (R2). The maximum Langmuir biosorbent capacity (qmax) was approximately 39 mg/g. The thermodynamic parameters were calculated for the process by which Pb(II) ions were removed by the peanut shells. According to these parameters, it was observed that the biosorption of Pb(II) ions by the peanut shells is exothermic and spontaneous.
TL;DR: In this paper, the adsorption properties of aminopropyltriethoxysilane (APS) modified microfibrillated cellulose (MFC) in aqueous solutions containing Ni(II), Cu(II) and Cd(II).
Abstract: The aim of the present study was to investigate the adsorption properties of aminopropyltriethoxysilane (APS) modified microfibrillated cellulose (MFC) in aqueous solutions containing Ni(II), Cu(II) and Cd(II) ions. The modified adsorbents were characterized using elemental analysis, Fourier transform infrared spectroscopy, SEM and zeta potential analysis. The adsorption and regeneration studies were conducted in batch mode using various different pH values and contact times. The maximum removal capacities of the APS/MFC adsorbent for Ni(II), Cu(II), and Cd(II) ions were 2.734, 3.150 and 4.195 mmol/g, respectively. The Langmuir, Sips and Dubinin-Radushkevich models were representative to simulate adsorption isotherms. The adsorption kinetics of Ni(II) Cu(II), and Cd(II) adsorption by APS/MFC data were modeled using the pseudo-first-order, pseudo-second-order and intra-particle diffusion kinetics equations. The results indicate that the pseudo-second-order kinetic equation and intra-particle diffusion model were adequate to describe the adsorption kinetics.
TL;DR: In this article, a batch adaption experiment of malachite green (MG) was studied with walnut shell (WS). Adsorption of MG onto WS was confirmed by FTIR analysis.
Abstract: Batch adsorption experiment of malachite green (MG) was studied with walnut shell (WS). Adsorption of MG onto WS was confirmed by FTIR analysis. Particle size, dosage, effect of dye concentration, pH, temperature and ionic strength were investigated. The optimized conditions for adsorption process in this study was carried out using WS of dosage 0.03 g/20 mL dye, at room temperature, ambient pH and agitation rate of 250 rpm for 2 h. The kinetics of the adsorption process was studied using four models: Lagergren 1st order, pseudo 2nd order, Weber–Morris intraparticle diffusion and the Boyd models. Kinetics data is best fitted with pseudo 2nd order. Weber–Morris model showed that intraparticle diffusion may be present, but is not the rate-limiting step while Boyd model suggested that film diffusion may be the controlling mechanism. Four isotherm models namely the Langmuir, Freundlich, Redlich–Peterson and Sips models were used for describing the adsorption process. The inclusion of non-linear isotherm models together with four error functions (ARE, EABS, χ 2 and MSPD) suggested the Langmuir model best described the adsorption process. The Langmuir isotherm predicted the maximum monolayer adsorption capacity of 90.8 mg g −1 . Thermodynamic studies showed that adsorption system is spontaneous and endothermic in nature. Regeneration of WS was investigated using three different solvent solutions and the results showed 0.1 M NaOH was able to regenerate and improve the adsorption capability of WS. Based on all the data in this study, WS is a potential low-cost material for the removal of MG.
TL;DR: Graphene-like layered molybdenum disulfide (g-MoS2) was prepared by hydrothermal synthesis method, which was characterized by atomic force microscopy (AFM), X-ray powder diffraction (XRD), Xray photoelectron spectroscopy (XPS) as discussed by the authors.
TL;DR: In this article, a MIL-101(Cr)/graphite oxide (GO) composites (MIL-101@GO) were synthesized by a solvothermal synthesis method, which was characterized by X-ray diffraction, scanning electron microscopy, adsorption of nitrogen, FT-IR spectroscopy and thermal analysis.
TL;DR: In this article, an activated carbon produced from buriti shells (AC b ) using ZnCl 2 as activating agent and its ability to remove methylene blue dye (MB) from aqueous solutions was reported.
TL;DR: A series of silica gel supported salicylaldehyde modified PAMAM dendrimers are favorable and useful for the uptake of Hg (II), and can be potentially used as promising adsorbents for the effective removal of HG(II) from aqueous solution.
TL;DR: In this paper, the adsorption capacity of waste materials of Daucus carota plant (carrot stem powder: CSP and carrot leaves powder: CLP) was explored for the removal of methylene blue (MB) malachite green (MG) dye from water.
TL;DR: The present study aimed to experimental design optimization applied to removal of malachite green from aqueous solution by ultrasound-assisted removal onto the gold nanoparticles loaded on activated carbon (Au-NP-AC), showing the suitability and applicability of the Langmuir model.
TL;DR: Potentiometric titrations showed that the modified activated carbon (ZrOx-AC) possesses positive charge at pH lower than 7, and FTIR analysis demonstrated that zirconium ions interact mainly with carboxylic groups on the activated carbon surfaces.
Abstract: When activated carbon (AC) is modified with zirconium(IV) by impregnation or precipitation, the fluoride adsorption capacity is typically improved. There is significant potential to improve these hybrid sorbents by controlling the impregnation conditions, which determine the assembly and dispersion of the Zr phases on carbon surfaces. Here, commercial activated carbon was modified with Zr(IV) together with oxalic acid (OA) used to maximize the zirconium dispersion and enhance fluoride adsorption. Adsorption experiments were carried out at pH 7 and 25 °C with a fluoride concentration of 40 mg L–1. The OA/Zr ratio was varied to determine the optimal conditions for subsequent fluoride adsorption. The data was analyzed using the Langmuir and Freundlich isotherm models. FTIR, XPS, and the surface charge distribution were performed to elucidate the adsorption mechanism. Potentiometric titrations showed that the modified activated carbon (ZrOx-AC) possesses positive charge at pH lower than 7, and FTIR analysis d...
TL;DR: In this paper, the activation of activated carbon (AC) was applied for the removal of methylene blue (MB) from aqueous solutions and the experimental data at various times was evaluated and modeled by different kinetic equation such as pseudo first order, pseudo second order, Elovich and intraparticle diffusion models according to correlation coefficient, it was found that the kinetic data follow the Elovich equation.
TL;DR: In this article, chitosan beads were produced from chitosa flakes and grafted with polyaniline to enhance the adsorption properties of chitoshan-based material for copper (II) ions.
Abstract: In this study, chitosan beads were produced from chitosan flakes and grafted with polyaniline to enhance the adsorption properties of chitosan based material for copper (II) ions. Chitosan and polyaniline graft chitosan beads (PGCB) were characterized by FTIR and SEM to provide evidence of successful grafting. The effect of pH, pHpzc, contact time and initial concentration was investigated in a batch system. Equilibrium data were obtained from the adsorption experiment carried out at different initial ion concentration. The data were fitted to the Langmuir and Freundlich isotherm at temperatures of 25 °C, 35 °C and 45 °C. The Langmuir model gave the best fit for both adsorbent. The maximum adsorption capacity for chitosan and PGCB at a temperature of 45 °C was found to be 52.6 mg/g and 100 mg/g, respectively and at a solution pH of 5. Thermodynamic parameters of the adsorption process such as the standard Gibb's free energy change (ΔG°), standard enthalpy change (ΔH°), and standard entropy change (ΔS°) were calculated, and the result showed that adsorption of copper onto PGCB is spontaneous and endodermic in nature. The pseudo-first-order and pseudo-second-order were used to analyze kinetic data. The data fit well with the second-order kinetic model. Desorption of copper ions from loaded PGCB was efficient, 0.5 M HCl was successfully used in desorbing the beads loaded with copper ions and a percentage desorption of 97.1% was achieved at contact time of 180 min.
TL;DR: Montmorillonite clay modified with iron oxide (MtMIO) was prepared for use as an adsorbent of methylene blue dye in this article, where the activation energy of + 19.32 kJ−mol−1 was determined using the Arrhenius equation.
TL;DR: The kinetics of adsorption of MG onto Alg-Fe3O4 nanoparticles were investigated using the pseudo-first-order and pseudo-second-order kinetic models and the results showed that the adsorbent dosage, pH and temperature were investigated on the advertisersorption properties of MG.