scholarly journals Removing of Hexavalent Chromium from Aqueous Solutions Using Dried Yogurt, and Studying Isotherm, Kinetic and Thermodynamic Parameters

2019 ◽  
Vol 16 (3) ◽  
pp. 0603
Author(s):  
Sultan Et al.
Keyword(s):  
Aqueous Solutions ◽  
Thermodynamic Parameters ◽  
Hexavalent Chromium ◽  
Treatment Time ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Order Kinetic ◽  
Kinetic And Thermodynamic Parameters ◽  
Pseudo Second Order ◽  
Adsorbent Treatment

     In this study, Yogurt was dried and milled, then shaked with distilled water to remove the soluble materials, then again dried and milled. Batch experiments were carried out to remove hexavalent chromium from aqueous solutions. Different parameters were optimized such as amount of adsorbent, treatment time, pH and concentration of adsorbate. The concentrations of Cr6+ in solutions are determined by UV-Visible spectrophotometer.  Maximum percentage removal of Cr6+ was 82% at pH 2. Two equilibrium adsorption isotherms mechanisms are tested Langmuir and Freundlich, the results showed that the isotherm obeyed to Freundlich isotherm. Kinetic models were applied to the adsorption of Cr6+ ions on the adsorbents, pseudo-first-order, the pseudo second-order respectively. Results showed that pseudo second-order kinetic model was applicable to the experimental data well. The thermodynamic parameters such as ΔGº, ΔHº and ΔSº were calculated. ∆H°, ∆S° and ΔGº for this study were negative indicating that the process is exothermic, while negative values of ΔGº indicate spontaneous process.

Evaluation of Chitosan Modified by Sodium Dodecyl Sulfate for Removing Hexavalent Chromium from Aqueous Solutions

2020 ◽  
pp. 13-22
Keyword(s):  
Sodium Dodecyl Sulfate ◽  
Aqueous Solutions ◽  
Hexavalent Chromium ◽  
Sodium Dodecyl ◽  
Second Order ◽  
Order Kinetic ◽  
Batch Mode ◽  
Dodecyl Sulfate ◽  
Pseudo Second Order ◽  
Langmuir And Freundlich Models

Hexavalent chromium (Cr(VI)) has the characteristic of forming anionic species, which are very toxic, very soluble in water and difficult to be removed. In this study, dichromate removal from aqueous solutions by chitosan and chitosan modified by sodium dodecyl sulfate (SDS) was addressed. The effect of various experimental parameters, such as pH (1-9), initial concentration (10-100 mg L-1), adsorbent dose (0.005-0.350 g) and contact time (5-60 min) was investigated. All experiments were conducted in batch mode at room temperature (~21 oC). The obtained equilibrium adsorption isotherms were analyzed using the Langmuir and Freundlich models. Furthermore, the kinetics of dichromate removal was analyzed by pseudo-first order, pseudo-second order and the Elovich models. Optimum conditions for obtaining high removal (~97%) within a relatively short time (60 min) are: 5.0 pH, 0.100 g SDS-chitosan dosage and an initial Cr2O72- concentration of 10 mg L-1. The dichromate adsorption capacity of chitosan is 8.3 mg L-1, while that of SDS-chitosan is 9.7 mg L-1. In addition, the adsorption of dichromate by chitosan and SDS-chitosan is well-fitted by the Langmuir and Freundlich models while the adsorption kinetics is best fitted by the pseudo-second-order kinetic model.

scholarly journals Kinetics and Isotherm Studies on Adsorption of Hexavalent Chromium Using Activated Carbon from Water Hyacinth

2021 ◽  
Vol 15 (1) ◽  
pp. 1-8
Author(s):  
Angelica Macalalad ◽  
◽  
Quennie Rose Ebete ◽  
Dominic Gutierrez ◽  
Madelaine Ramos ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Hexavalent Chromium ◽  
Water Hyacinth ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Order Kinetic ◽  
Adsorbate Concentration ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The present study is focused on the use of activated carbon derived from water hyacinth (WH-AC) as adsorbent for the removal of Cr(VI) from aqueous solution. The optimized WH-AC was found to be mesoporous and considered as granular. The surface area of 11.564 m2/g was found to have a good adsorption capacity. The adsorption data of the optimized WH-AC followed a pseudo-second order kinetics and the Freundlich isotherm model. Based on the correlation coefficient obtained from pseudo-second-order kinetic model, the R2 values were all above 0.99, which is closer to unity of one (1) indicating that it followed a chemisorption process. The adsorption capacity of WH-AC increased from 1.98 to 4.68 mg/g when adsorbate concentration increased from 20 to 50 mg/l. The overall study proved that the adsorption by activated carbon derived from water hyacinth can be an alternative and efficient technique in hexavalent chromium removal.

scholarly journals Thermodynamic, Kinetic, and Equilibrium Parameters for the Removal of Lead and Cadmium from Aqueous Solutions with Calcium Alginate Beads

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ruth Alfaro-Cuevas-Villanueva ◽  
Aura Roxana Hidalgo-Vázquez ◽  
Consuelo de Jesús Cortés Penagos ◽  
Raúl Cortés-Martínez
Keyword(s):  
Aqueous Solutions ◽  
Thermodynamic Parameters ◽  
Calcium Alginate ◽  
Alginate Beads ◽  
Second Order ◽  
Order Kinetic ◽  
Calcium Alginate Beads ◽  
Kinetic And Thermodynamic Parameters ◽  
Lead And Cadmium ◽  
Cadmium And Lead

The sorption of cadmium (Cd) and lead (Pb) by calcium alginate beads (CAB) from aqueous solutions in batch systems was investigated. The kinetic and thermodynamic parameters, as well as the sorption capacities of CAB in each system at different temperatures, were evaluated. The rate of sorption for both metals was rapid in the first 10 minutes and reached a maximum in 50 minutes. Sorption kinetic data were fitted to Lagergren, pseudo-second-order and Elovich models and it was found that the second-order kinetic model describes these data for the two metals; comparing kinetic parameters for Cd and Pb sorption a higher kinetic rate (K2) for Pb was observed, indicating that the interaction between lead cations and alginate beads was faster than for cadmium. Similarly, isotherm data were fitted to different models reported in literature and it was found that the Langmuir-Freundlich (L-F) and Dubinin-Radushkevich (D-R) models describe the isotherms in all cases. CAB sorption capacity for cadmium was 27.4 mg/g and 150.4 mg/g for lead, at 25°C. Sorption capacities of Cd and Pb increase as temperature rises. According to the thermodynamic parameters, the cadmium and lead adsorption process was spontaneous and endothermic. It was also found that pH has an important effect on the adsorption of these metals by CAB, as more were removed at pH values between 6 and 7.

scholarly journals Biosorption of Hexavalent Chromium Metal Ions by Lentinula Edodes Biomass: Kinetic, Isothermal, and Thermodynamic Parameters

2021 ◽  
Vol 68 (3) ◽  
pp. 587-593
Author(s):  
Aslı Göçenoğlu Sarıkaya
Keyword(s):  
Thermodynamic Parameters ◽  
Hexavalent Chromium ◽  
Lentinula Edodes ◽  
Freundlich Isotherm ◽  
Chromium Concentration ◽  
Infrared Spectrometry ◽  
Order Kinetic ◽  
Biosorption Capacity ◽  
Kinetic And Thermodynamic Parameters ◽  
Biosorption Process

Lentinula edodes was investigated as a biosorbent for hexavalent chromium biosorption in this study. To examine the optimum conditions of biosorption, the pH of the hexavalent chromium solution, biosorbent dosage, temperature, contact time, and initial hexavalent chromium concentration were identified. Further, to clarify the biosorption mechanism process, the isothermal, kinetic, and thermodynamic parameters were determined. The functional groups and surface morphology of the biosorbent were identified using Fourier transform infrared spectrometry and scanning electron microscopy in the absence and presence of hexavalent chromium, respectively. Based on the results, the maximum biosorption capacity was determined as 194.57 mg g–1 under acidic conditions at 45 °C. From the kinetics studies, the biosorption process was observed to follow the Freundlich isotherm and pseudo-second-order kinetic models well. Thus, L. edodes as a biosorbent has potential usage for wastewater treatment owing to its effective biosorption capacity.

Adsorption of Congo Red Dye from Aqueous Solutions by Montmorillonite as a Low-cost Adsorbent

2017 ◽  
Vol 16 (1) ◽  
Author(s):  
Yusef Omidi Khaniabadi ◽  
Hassan Basiri ◽  
Heshmatollah Nourmoradi ◽  
Mohammad Javad Mohammadi ◽  
Ahmad Reza Yari ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Congo Red ◽  
Low Cost ◽  
Aqueous Media ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Effective Option ◽  
Pseudo Second Order

AbstractIn this study, the sorption of Congo red (CR), as a toxic dye, from aqueous media was investigated using montmorillonite (MMT) as a low-cost adsorbent. The influence of several factors such as contact time, pH, adsorbent dosage, dye content, and ionic strength was investigated on the dye removal. MMT was characterized by Fourier transformed infrared (FTIR) spectroscopy and X-ray diffractometer (XRD). Different kinetic and isotherm models including pseudo-first and pseudo-second order kinetic and Langmuir and Freundlich were applied to analyze experimental data, respectively. The results showed that the data were well fitted by pseudo-second-order kinetic and Freundlich isotherm models. The optimum conditions for the sorption of CR were achieved over 40 min and at pH=2. According to the results of the present study, MMT can be used as a low-cost, eco-friendly and effective option for the adsorption of CR from aqueous solutions.

Synthesis and Characterization of Chitosan templated Mesoporous Silica: Efficient use of Mesoporous Silica in the removal of Cu(II) from Aqueous Solutions

2016 ◽  
Vol 4 (2) ◽  
pp. 105-112
Author(s):  
Lalchhing puii ◽  
◽  
Seung-Mok Lee ◽  
Diwakar Tiwari ◽  
◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Aqueous Solutions ◽  
Background Electrolyte ◽  
Second Order ◽  
Order Kinetic ◽  
Sorption Data ◽  
Column Reactor ◽  
Wide Ph Range ◽  
Freundlich Adsorption Isotherm ◽  
Pseudo Second Order

A mesoporous silica was synthesized by annealing (3-Aminopropyl) triethoxysilane grafted chitosan at 800˚C. The mesoporous silica was characterized by the XRD (X-ray diffraction) analysis. The BET specific surface area and pore size of silica was found to be 178.42 m2/g and 4.13 nm. The mesoporous silica was then employed for the efficient remediation of aqueous solutions contaminated with Cu(II) under batch and column reactor operations. The mesoporous silica showed extremely high per cent removal of Cu(II) at wide pH range i.e., pH ~2.0 to 7.0. Relatively a fast uptake of Cu(II) was occurred and high percentage removal was obtained at initial concentrations studied from 1.0 to 15.0 mg/L. The equilibrium state sorption data were utilized for the Langmuir and Freundlich adsorption isotherm studies. Moreover, the effect of an increase in background electrolyte concentrations from 0.0001 to 0.1 mol/L NaNO3 was assessed for the uptake of Cu(II) by mesoporous silica. The equilibrium sorption was achieved within 240 min of contact and the kinetic data is best fitted to the pseudo-second-order and fractal like pseudo-second-order kinetic models. In addition, the mesoporous silica was used for dynamic studies under column reactor operations. The breakthrough curve was then used for the non-linear fitting of the Thomas equation and the loading capacity of the column for Cu(II) was estimated.

Kinetics of lead ion biosorption from aqueous solution onto lyophilized Aspergillus niveus

2010 ◽  
Vol 5 (1) ◽  
Author(s):  
Hülya Karaca ◽  
Turgay Tay ◽  
Merih Kıvanç
Keyword(s):  
Adsorption Capacity ◽  
Correlation Coefficients ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Lead Ions ◽  
Lead Ion ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Aspergillus Niveus ◽  
Pseudo Second Order

The biosorption of lead ions (Pb2+) onto lyophilized fungus Aspergillus niveus was investigated in aqueous solutions in a batch system with respect to pH, contact time and initial concentration of the ions at 30 °C. The maximum adsorption capacity of lyophilized A. niveus was found to be 92.6 mg g−1 at pH 5.1 and the biosorption equilibrium was established about in 30 min. The adsorption capacity obtained is one of the highest value among those reported in the literature. The kinetic data were analyzed using the pseudo-first-order kinetic, pseudo-second-order kinetic, and intraparticle diffusion equations. Kinetic parameters, such as rate constants, equilibrium adsorption capacities, and related correlation coefficients for the kinetic models were calculated and discussed. It was found that the adsorption of lead ions onto lyophilized A. niveus biomass fit the pseudo-second-order kinetic model well. The Langmuir and Freundlich isotherm parameters for the lead ion adsorption were applied and the Langmuir model agreed better with the adsorption of lead ions onto lyophilized A. niveus.

scholarly journals Sythesis of Nano Zerovalent Iron Supported Sawdust (NZVI/SD) and Its Application for Removal of Arsenic (III) from Aqueous Solution

2020 ◽  
pp. 1-12
Author(s):  
Tasrina R. Choudhury ◽  
Snahasish Bhowmik ◽  
M. S. Rahman ◽  
Mithun R. Nath ◽  
F. N. Jahan ◽  
...  
Keyword(s):  
Ph Value ◽  
Ferrous Sulphate ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Zerovalent Iron ◽  
Isotherm Model ◽  
Order Kinetic ◽  
Adsorption Sites ◽  
Adsorption Data ◽  
Pseudo Second Order

Sawdust supported nano-zerovalent (NZVI/SD) iron was synthesized by treating sawdust with ferrous sulphate followed by reduction with NaBH4. The NZVI/SD was characterized by SEM, XRD, FTIR and Chemical method. Adsorption of As (III) by NZVI/SD was investigated and the maximum uptake of As (III) was found at pH value of 7.74 and equilibrium time of 3 hrs. The adsorption isotherm modelling revealed that the equilibrium adsorption data were better fitted with the Langmuir isotherm model compared with the Freundlich Isotherm model. This study revealed that the maximum As (III) ions adsorption capacity was found to be 12.66 mg/g for using NZVI/SD adsorbent. However, the kinetics data were tested by pseudo-first-order and pseudo-second-order kinetic models; and it was observed that the adsorption data could be well fitted with pseudo-second-order kinetics for As (III) adsorption onto NZVI/SD depending on both adsorbate concentration and adsorption sites. The result of this study suggested that NZVI/SD could be developed as a prominent environment-friendly adsorbent for the removal of As (III) ions from aqueous systems.

Mathematical Modelling for Copper and Lead Adsorption on Coffee Grounds

2017 ◽  
Author(s):  
Jurgita Seniūnaitė ◽  
Rasa Vaiškūnaitė ◽  
Kristina Bazienė
Keyword(s):  
Heavy Metals ◽  
Mathematical Modelling ◽  
Adsorption Kinetics ◽  
Adsorption Process ◽  
Freundlich Isotherm ◽  
Sorption Process ◽  
Second Order ◽  
Order Kinetic ◽  
Coffee Grounds ◽  
Pseudo Second Order

Research studies on the adsorption kinetics are conducted in order to determine the absorption time of heavy metals on coffee grounds from liquid. The models of adsorption kinetics and adsorption diffusion are based on mathe-matical models (Cho et al. 2005). The adsorption kinetics can provide information on the mechanisms occurring be-tween adsorbates and adsorbents and give an understanding of the adsorption process. In the mathematical modelling of processes, Lagergren’s pseudo-first- and pseudo-second-order kinetics and the intra-particle diffusion models are usually applied. The mathematical modelling has shown that the kinetics of the adsorption process of heavy metals (copper (Cu) and lead (Pb)) is more appropriately described by the Lagergren’s pseudo-second-order kinetic model. The kinetic constants (k2Cu = 0.117; k2Pb = 0,037 min−1) and the sorption process speed (k2qeCu = 0.0058–0.4975; k2qePb = 0.021–0.1661 mg/g per min) were calculated. After completing the mathematical modelling it was calculated that the Langmuir isotherm better reflects the sorption processes of copper (Cu) (R2 = 0.950), whilst the Freundlich isotherm – the sorption processes of lead (Pb) (R2 = 0.925). The difference between the mathematically modelled and experimen-tally obtained sorption capacities for removal of heavy metals on coffee grounds from aqueous solutions is 0.059–0.164 mg/l for copper and 0.004–0.285 mg/l for lead. Residual concentrations of metals in a solution showed difference of 1.01 and 0.96 mg/l, respectively.

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.

Sign in / Sign up

Export Citation Format

Share Document