scholarly journals KINETICS AND EQUILIBRIUM MODEL OF Pb(II) AND Cd(II) ADSORPTION ONTO TETRAKIS-THIOMETHYL-C-4-METHOXYPHENYLCALIX[4]RESORCINARENE

2012 ◽  
Vol 12 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Suryadi Budi Utomo ◽  
Jumina Jumina ◽  
Dwi Siswanta ◽  
Mustofa Mustofa
Keyword(s):  
Metal Ions ◽  
Metal Binding ◽  
Order Kinetic ◽  
Adsorption Model ◽  
Freundlich Model ◽  
Optimum Ph ◽  
Before And After ◽  
Pseudo Second Order ◽  
Langmuir And Freundlich Equations ◽  
Equilibrium Adsorption Isotherm

The ability of tetrakis-thiomethyl-C-4-methoxyphenylcalix[4]resorcinarene for trapping Pb(II) and Cd(II) from aqueous solution at different pH, contact times, and initial metal concentration was investigated. Concentration of metal ions before and after interaction was analyzed by Atomic Absorption Spectrophotometer (AAS). The result indicated that tetrakis-thiomethyl-C-4-methoxyphenylcalix[4]resorcinarene is a good host for metal ions, where Cd(II) sorption capacity was higher than that of Pb(II). Effect of pH on batch experiments for the mentioned ions indicated that the optimum pH for metal binding were 5 for both of lead(II) and cadmium(II). In order to investigate the mechanism of adsorption, the 1st-order, pseudo 1st-order, and pseudo 2nd-order kinetic models were used. The adsorption model of metal ions on the resorcinarene followed pseudo second order of Ho & McKay expression. The equilibrium adsorption isotherm has been analyzed by Langmuir and Freundlich equations. Langmuir model had the higher correlation coefficient than that of Freundlich model.

scholarly journals THE ADSORPTION OF Pb(II) AND Cr(III) BY POLYPROPYLCALIX[4]ARENE POLYMER

2010 ◽  
Vol 9 (3) ◽  
pp. 437-444 ◽  
Author(s):  
Suryadi Budi Utomo ◽  
Jumina Jumina ◽  
Tutik Dwi Wahyuningsih
Keyword(s):  
Metal Binding ◽  
Adsorption Equilibrium ◽  
Yellow Crystal ◽  
Maximum Adsorption Capacity ◽  
Adsorption Model ◽  
Heavy Metal Cations ◽  
Optimum Ph ◽  
Isotherm Adsorption ◽  
Pseudo Second Order ◽  
Relative Molecular Weight

A research has been conducted to investigate the adsorption behavior of Pb(II) and Cr(III) onto polypropylcalix[4]arene polymer. The polypropylcalix[4]arene polymer was synthesized in the presence of H2SO4 catalyst and chloroform under N2 condition for 5 h using 25-allyloxy-26,27,28-trihydroxycalyx[4]arene as the precursor. The Polymer was obtained as yellow crystal with melting point of  288-290 °C and its relative molecular weight was 44.810 g.mol-1. The application of polypropylcalix[4]arene for trapping heavy metal cations and its adsorption model were examined by stirring the suspension of the calixarene in the sample solutions for various pH, time, and concentration of Pb(II) and Cr(III) solution. Effect of pH on batch experiments for the mentioned ions indicated that the optimum pH for metal binding were 5 for lead(II) and chromium(III). The adsorption model of metal ions on polypropylcalix[4]arene followed both the pseudo second order adsorption of Ho's and Langmuir isotherm adsorption kinetics models with rate constant (k) were 6.81 x 101 min-1 for Pb(II) and 2.64 x 10-2 min-1 for Cr(III). The adsorption equilibrium constant, K, were 5.84 x 105 L.mol-1 for Pb(II) and 4.66 x 105 L.mol-1 for Cr(III). The maximum adsorption capacity of polypropylcalix[4]arene to Pb(II) and Cr(III) were 16.31 and 18.14 mg.g-1 with adsorption energy of 32.90 and 32.34 kJ.mol-1, respectively.   Keywords: polypropylcalix[4]arene, adsorption, Pb(II), and Cr(III)

scholarly journals Chromium and nickel metal ions removal from contaminated water using Nigerian bentonite clay

2021 ◽  
Author(s):  
Jock Asanja Alexander ◽  
Oboh Oseribo Innocent ◽  
Uwem Ekwere Inyang ◽  
Ganchok Lawrence ◽  
Adeku Ojo
Keyword(s):  
Metal Ions ◽  
Bentonite Clay ◽  
Textural Properties ◽  
Order Kinetic ◽  
Nickel Metal ◽  
Batch Mode ◽  
Freundlich Model ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Maximum Removal

Abstract In this work bentonite clay was characterized and investigated for the adsorption of chromium and nickel metal ions from aqueous solution. The clay calcined at 650 °C was characterized for physical, chemical and textural properties. Nickel sulphate hexahydrate (NiSO4.6H2O) and chromium tri oxide (Cr2O3) solutions were used as metal model compounds to evaluate the adsorption efficiency of the clay in a batch mode. The initial metal ions concentration range from 10 to 50 mg/L and the maximum removal efficiency was 99.40% for Cr (III) and 71.50% for Ni (II) metal ions. Langmuir and Freundlich models were utilized for the analysis of adsorption equilibrium isotherm. The experimental data fitted well into Freundlich model for Cr (III) with regression coefficient (R2) of 0.996 and the Langmuir model for Ni (II) having R2 value 0.994. The Pseudo second order kinetic model fitted well for both chromium and nickel and their adsorption from single metal solutions followed the order Cr > Ni. Highlight The local clay has not been reported in any scholarly journal or publication. Theremoval of nickel and chromium using this clay has been found effective. The dataobtained will form a baseline for references and learning purposes.

scholarly journals Cr(VI) adsorption from aqueous streams on eggshell membranes of different birds used as biosorbents

2020 ◽  
Vol 38 (9-10) ◽  
pp. 413-434
Author(s):  
Jessica Badillo-Camacho ◽  
Eulogio Orozco-Guareño ◽  
Gregorio G Carbajal-Arizaga ◽  
Ricardo Manríquez-Gonzalez ◽  
Icela D Barcelo-Quintal ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Freundlich Model ◽  
Membrane Surfaces ◽  
Adsorption Isotherm Models ◽  
Before And After ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Efficient Option

The discharges enriched with heavy metals, particularly Cr(VI), are a serious environmental problem. In this work, it is presented the use of biosorbents from eggshells membranes of ostrich, quail, duck and chicken; the membranes were easily prepared and studied for the removal of Cr(VI) from aqueous solutions. Maximum uptake of 1.41 mmol g−1 membrane permitted the identification of ostrich membrane as the material with the highest Cr(VI) uptake. N2 adsorption experiments permitted to classify ostrich membranes as mesoporous materials, since they had pore size of 14.8 nm. This represented an advantage on the nature of these membranes to be used as biosorbents with respect to other membranes. The adsorption isotherm models such as Langmuir and Freundlich were verified using experimental data. Langmuir model described the adsorption process satisfactorily at pH 1 and 2 whereas Freundlich model fitted data better at pH 3 and 5. The adsorption kinetic data were adjusted to a pseudo-second order kinetic model. TGA results permitted demonstrating a low thermal stability of ostrich membrane, since it starts decomposing at around 50°C due to the fact that membranes have about 60% protein. Through SEM microscopy was possible to observe the morphology of the membrane surfaces before and after Cr(VI) uptake which reflects the textural characteristics of the biosorbent. FTIR and XPS analyses suggested that Cr was adsorbed on ostrich membranes through the amine groups of proteins conforming the fibers of membranes. Despite the oxygen shows higher electronegativity than N, Cr shows more preference toward N due to fact that pH conditions favor the positive charges on the surface of the membrane. Our results make evident that this waste material is a novel and efficient option for the removal of Cr(VI) from aqueous solutions.

Adsorption Mechanism of Attapulgite for Cu(ΙΙ) in Aqueous Solution

2014 ◽  
Vol 1065-1069 ◽  
pp. 1867-1870
Author(s):  
Jun Ren ◽  
Ya Qiong Zhao ◽  
Dong Dong Gou ◽  
Ling Tao ◽  
Mei Wei Zhang
Keyword(s):  
Adsorption Mechanism ◽  
Entropy Change ◽  
Order Kinetic ◽  
Gibbs Free Energy Change ◽  
Temperature Dependent ◽  
Sorption Data ◽  
Freundlich Model ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Equilibrium Adsorption Isotherm

Adsorption of Cu(Ⅱ) onto natural attapulgite was investigated with respect to temperature, initial concentration and contact time. The adsorption process can be well described by the pseudo-second-order kinetic model, and the equilibrium adsorption isotherm was closely fitted with the Freundlich model. Enthalpy change(△H0), entropy change(△S0) and Gibbs free energy change(△G0) were calculated from the temperature dependent sorption data, and the results indicated that the sorption of Cu(Ⅱ) on attapulgite was a spontaneous process, and the sorption was endothermic.

scholarly journals Optimization of cadmium(II) adsorption onto modified and unmodified lignocellulosics (rice husk and egussi peeling)

2015 ◽  
Vol 5 (1) ◽  
pp. 45
Author(s):  
Tchuifon Tchuifon Donald Raoul ◽  
Nche George Ndifor-Angwafor ◽  
Ngakou Sadeu Christian ◽  
Kamgaing Théophile ◽  
Ngomo Horace Manga ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Rice Husk ◽  
Order Kinetic ◽  
Adsorption Model ◽  
Batch Technique ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Adsorbed Quantity ◽  
Minimal Mass ◽  
Modified Adsorbents

<p>The present study is based on the adsorption of cadmium (II) ions on rice husk and egussi peeling, unmodified and modified with nitric acid in aqueous solution, using batch technique. It was carried out as a function of contact time, dosage, pH and initial concentration. The equilibrium time was achieved within 25 minutes for unmodified rice husk (Glu NT) and 20 minutes for unmodified egussi peeling (Cuc NT) with an adsorbed quantity of 13.18 mg/g. In the case of modified materials, we obtained 15 minutes for modified rice husk (Glu HNO3) and 10 minutes for modified egussi peeling (Cuc HNO3) with an adsorbed quantity of 18.77 mg/g. The maximum biosorption occurred at pH 5.5 for all biosorbents. The adsorbent mass for maximum adsorption was 0.4 g giving an adsorption capacity of 62.02 % for unmodified adsorbents. In the case of modified adsorbents, the minimal mass at which maximum adsorption occurred was 0.4 g giving an adsorption capacity of 98.33 % and 0.6 g giving an adsorption capacity of 98.33 % for modified rice husk and egussi peeling respectively. The adsorbent/adsorbate equilibrium was well described by the pseudo-second order kinetic model and by Langmuir’s and Freundlich adsorption model. This models showed that the adsorption of cadmium (II) is a chemisorption process.</p>

scholarly journals Adsorption of Cr(VI) ions onto goethite, activated carbon and their composite: kinetic and thermodynamic studies

2020 ◽  
Vol 10 (9) ◽  
Author(s):  
G. B. Adebayo ◽  
H. I. Adegoke ◽  
Sidiq Fauzeeyat
Keyword(s):  
Activated Carbon ◽  
Heavy Metal Contamination ◽  
Stem Bark ◽  
Order Kinetic ◽  
Adsorption Capacities ◽  
Optimum Ph ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Daniellia Oliveri ◽  
Kinetic And Thermodynamic Studies

Abstract Hexavalent chromium was adsorbed from aqueous solution with three prepared and characterized adsorbents, namely goethite (G), activated carbon (AC) and their composite (GAC). The goethite particle was synthesized using the precipitation methods, and activated carbon was prepared from the stem bark of Daniellia oliveri tree and composite in a ratio of 1:5 goethite–activated carbon. The adsorption capacities of G, AC and GAC for Cr(VI) are 6.627, 5.455 and 6.354 mg/g with 0.02 g adsorbent within contact time of 60, 180 and 30 min for G, AC and GAC, respectively, for Cr(VI) adsorption at optimum pH of 3. The isotherm studied was best explained by Langmuir adsorption isotherm and fitted with the pseudo-second-order kinetic model. Desorption studies showed that 1.0 M HNO3 was a better desorbing agent than 0.1 M HNO3, 0.1 M HCl and 1.0 M HCl. Chromium was most desorbed (94.60% in Cr//G using 1 M HNO3). The result obtained revealed that goethite and activated carbon produced are favourable adsorbents and the composite of the two adsorbents gives a more favourable, economical and affordable adsorbent for the clean-up of heavy metal contamination.

scholarly journals Enhanced removal of hexavalent chromium by different acid-modified biochar derived from corn straw: behavior and mechanism

2020 ◽  
Vol 81 (10) ◽  
pp. 2270-2280
Author(s):  
Yonggang Xu ◽  
Tianxia Bai ◽  
Yubo Yan ◽  
Yunfeng Zhao ◽  
Ling Yuan ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Hydrogen Ion ◽  
Corn Straw ◽  
Order Model ◽  
Freundlich Model ◽  
X Ray ◽  
Modified Biochar ◽  
Before And After ◽  
Pseudo Second Order ◽  
Kinetics Of

Abstract It is of great significance to remove Cr(VI) from water as a result of its high toxicity. Biochar from corn straw was modified by different acids (HNO3, H2SO4 and H3PO4) to remove Cr(VI) from aqueous solution. To estimate the removal mechanisms of Cr(VI) by the acid-modified biochars, batch experiments were performed in the light of contact time, Cr(VI) concentration, and pH, and the characteristics of acid-modified biochars before and after Cr(VI) adsorption were investigated by Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectroscopy (XPS). The adsorption kinetics of Cr(VI) by acid-modified biochars were consistent with the pseudo-second-order model, and the adsorption isotherm obeyed the Freundlich model. Furthermore, the acid- modified biochars could supply more oxygen-containing functional groups (-COOH and -OH) as electron donor (e−) and hydrogen ion (H+) to enhance the reduction of Cr(VI) to Cr(III), resulting in enhanced removal of Cr(VI). HNO3-modified biochar exhibited the highest removal efficiency of Cr(VI). In general, the acid modifition of biochar was an effective method to increase the removal of Cr(VI).

scholarly journals The Removal of Uranium and Thorium from Their Aqueous Solutions by 8-Hydroxyquinoline Immobilized Bentonite

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 626 ◽  
Author(s):  
Salah ◽  
Gaber ◽  
Kandil
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Langmuir Isotherm ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
X Ray ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The sorption of uranium and thorium from their aqueous solutions by using 8-hydroxyquinoline modified Na-bentonite (HQ-bentonite) was investigated by the batch technique. Na-bentonite and HQ-bentonite were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier Transform Infrared (FTIR) spectroscopy. Factors that influence the sorption of uranium and thorium onto HQ-bentonite such as solution pH, contact time, initial metal ions concentration, HQ-bentonite mass, and temperature were tested. Sorption experiments were expressed by Freundlich and Langmuir isotherms and the sorption results demonstrated that the sorption of uranium and thorium onto HQ-bentonite correlated better with the Langmuir isotherm than the Freundlich isotherm. Kinetics studies showed that the sorption followed the pseudo-second-order kinetic model. Thermodynamic parameters such as ΔH°, ΔS°, and ΔG° indicated that the sorption of uranium and thorium onto HQ-bentonite was endothermic, feasible, spontaneous, and physical in nature. The maximum adsorption capacities of HQ-bentonite were calculated from the Langmuir isotherm at 303 K and were found to be 63.90 and 65.44 for U(VI) and Th(IV) metal ions, respectively.

scholarly journals Removal of Lead(II) from Synthetic Wastewater by Lavandula pubescens Decne Biosorbent: Insight into Composition–Adsorption Relationship

2020 ◽  
Vol 10 (21) ◽  
pp. 7450
Author(s):  
Ali Q. Alorabi ◽  
Fahad A. Alharthi ◽  
Mohamed Azizi ◽  
Nabil Al-Zaqri ◽  
Adel El-Marghany ◽  
...  
Keyword(s):  
Ion Concentration ◽  
Wild Plant ◽  
Synthetic Wastewater ◽  
Gas Chromatography Mass Spectrometry ◽  
Gas Liquid Chromatography ◽  
Order Kinetic ◽  
Freundlich Model ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Best Fit

In this work, the widely-abundant, cheap, wild plant Lavandula pubescens Decne was evaluated as an adsorbent for removing Pb(II) ions from wastewater. The chemical composition of the plant was partially isolated and characterized by the corresponding techniques, including gas chromatography–mass spectrometry, gas liquid chromatography, and FTIR spectroscopy. The adsorption capacity of the dried plant material for Pb(II) ions increased with increasing contact time, initial ion concentration, and temperature, while it decreased with increasing adsorbent dosage. The optimum condition for Pb(II) adsorption was determined as 550 mg/L initial metal concentration, pH ≤ 7, and 90 min of contact. The best fit for Pb(II) adsorption isotherms was the linear form of the Freundlich model; however, the maximum capacity indicated by Langmuir was 91.32 mg/g. The experimental data fit better the pseudo-second-order kinetic model (R2 = 0.969), suggesting chemisorption process. Thermodynamic data revealed an endothermic, nonspontaneous, and adsorption process favored at higher concentrations.

scholarly journals Preparation and Adsorption Properties of Biochar/g-C3N4 Composites for Methylene Blue in Aqueous Solution

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaodong Li
Keyword(s):  
Methylene Blue ◽  
Thermodynamic Parameters ◽  
Raw Materials ◽  
Order Kinetic ◽  
Adsorption Effect ◽  
Freundlich Model ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Doping Ratio

Using straw and urea as raw materials, biochar (BC) and g-C3N4 were prepared by oxygen-free pyrolysis at 300°C and 550°C. BC/g-C3N4 was prepared by loading different amounts of g-C3N4 onto the surface of biochar and characterized by SEM and FT-IR. The adsorption effect on methylene blue (MB) was investigated from the aspects of dosage and pH. The studies of adsorption equilibrium isotherms and the kinetic and the thermodynamic parameters on the BC/g-C3N4 adsorbents are discussed. The results showed that BC/g-C3N4 0.16 g/L with a doping ratio of 1 : 3 was added to the MB solution with an initial concentration of 50 mg/L and pH=11. The adsorption rate and adsorption amount were 96.72% and 302.25 mg/g, respectively. The adsorption process included surface adsorption and intraparticle diffusion, which conformed to the pseudo-second-order kinetic model and Langmuir-Freundlich model. Thermodynamic parameters (ΔG0<0, ΔH0>0, and ΔS0>0) showed that the adsorption reaction is spontaneous, which positively correlated with temperature.

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