scholarly journals Sorption of phosphates and thiocyanates on isomorphic substituted Mg/Zn-Al-type hydrotalcites

2008 ◽  
Vol 73 (8-9) ◽  
pp. 835-843 ◽  
Author(s):  
Rodica Pode ◽  
Eveline Popovici ◽  
Laura Cocheci ◽  
Erika Reisz ◽  
Mihaela Seftel ◽  
...  
Keyword(s):  
Gibbs Energy ◽  
Standard Gibbs Energy ◽  
Physical Adsorption ◽  
Freundlich Isotherm ◽  
Sorption Data ◽  
Freundlich Isotherms ◽  
Data Standard ◽  
Langmuir And Freundlich Isotherms ◽  
Maximum Sorption ◽  
Equilibrium Data

The sorption equilibriums of phosphate and thiocyanate anions on isomorphic substituted Mg/Zn-Al-type hydrotalcites were investigated in this study. Langmuir and Freundlich isotherms were used to interpret the equilibrium data for phosphate. The sorption equilibriums of phosphate on Mg3Al, Mg2ZnAl and Mg1.5Zn1.5Al hydrotalcites were well described by the Langmuir isotherm. The highest maximum sorption capacities for these adsorbents were as follows: 111, 101 and 95 mg g-1. The equilibrium constant and standard Gibbs energy changes were also calculated from the sorption data. Standard Gibbs energy changes of about -20 kJ mol-1 indicated that the process might be considered as physical adsorption. The sorption equilibriums of phosphate on isomorphic substituted samples of MgZn2Al and Zn3Al were well described by the Freundlich isotherm. Thiocyanate showed a relative low affinity for the studied materials, as indicated by both the 'S'-shaped isotherms and low sorption capacities. The sorption of phosphate and thiocyanate on the investigated hydrotalcites showed a continuous decrease of the sorption capacity in the following order: Mg3Al > Mg2ZnAl > Mg1.5Zn1.5Al > MgZn2Al > Zn3Al.

scholarly journals Equilibrium and Kinetic Study of Anionic and Cationic Pollutants Remediation by Limestone–Chitosan–Alginate Nanocomposite from Aqueous Solution

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2586
Author(s):  
Inas A. Ahmed ◽  
Ahmed H. Ragab ◽  
Mohamed A. Habila ◽  
Taghrid S. Alomar ◽  
Enas H. Aljuhani
Keyword(s):  
Physical Adsorption ◽  
Low Cost ◽  
Freundlich Isotherm ◽  
Entropy Change ◽  
Sem Images ◽  
Bet Analysis ◽  
Adsorption Processes ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Multilayer Formation

In this work, low-cost and readily available limestone was converted into nanolimestone chitosan and mixed with alginate powder and precipitate to form a triple nanocomposite, namely limestone—chitosan–alginate (NLS/Cs/Alg.), which was used as an adsorbent for the removal of brilliant green (BG) and Congo red (CR) dyes in aqueous solutions. The adsorption studies were conducted under varying parameters, including contact time, temperature, concentration, and pH. The NLS/Cs/Alg. was characterized by SEM, FTIR, BET, and TEM techniques. The SEM images revealed that the NLS/Cs/Alg. surface structure had interconnected pores, which could easily trap the pollutants. The BET analysis established the surface area to be 20.45 m2/g. The recorded maximum experimental adsorption capacities were 2250 and 2020 mg/g for CR and BG, respectively. The adsorption processes had a good fit to the kinetic pseudo second order, which suggests that the removal mechanism was controlled by physical adsorption. The CR and BG equilibrium data had a good fit for the Freundlich isotherm, suggesting that adsorption processes occurred on the heterogeneous surface with a multilayer formation on the NLS/Cs/Alg. at equilibrium. The enthalpy change (ΔH0) was 37.7 KJ mol−1 for CR and 8.71 KJ mol−1 for BG, while the entropy change (ΔS0) was 89.1 J K−1 mol−1 for CR and 79.1 J K−1 mol−1 BG, indicating that the adsorption process was endothermic and spontaneous in nature.

scholarly journals Equilibrium, Kinetics, and Thermodynamics of the Removal of Nickel(II) from Aqueous Solution Using Cow Hooves

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
I. Osasona ◽  
O. O. Ajayi ◽  
A. O. Adebayo
Keyword(s):  
Aqueous Solution ◽  
Contact Time ◽  
Room Temperature ◽  
Physical Adsorption ◽  
Low Cost ◽  
Freundlich Isotherm ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Equilibrium Studies ◽  
Equilibrium Data

The feasibility of using powdered cow hooves (CH) for removing Ni2+ from aqueous solution was investigated through batch studies. The study was conducted to determine the effect of pH, adsorbent dosage, contact time, adsorbent particle size, and temperature on the adsorption capacity of CH. Equilibrium studies were conducted using initial concentration of Ni2+ ranging from 15 to 100 mgL−1 at 208, 308, and 318 K, respectively. The results of our investigation at room temperature indicated that maximum adsorption of Ni2+ occurred at pH 7 and contact time of 20 minutes. The thermodynamics of the adsorption of Ni2+ onto CH showed that the process was spontaneous and endothermic. Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm models were used to quantitatively analysed the equilibrium data. The equilibrium data were best fitted by Freundlich isotherm model, while the adsorption kinetics was well described by pseudo-second-order kinetic equation. The mean adsorption energy obtained from the D-R isotherm revealed that the adsorption process was dominated by physical adsorption. Powdered cow hooves could be utilized as a low-cost adsorbent at room temperature under the conditions of pH 7 and a contact time of 20 minutes for the removal of Ni(II) from aqueous solution.

Synthesis, Characterization and Adsorption Property of Expanded Graphite/Conducting Polymer Composite

2011 ◽  
Vol 322 ◽  
pp. 93-97 ◽  
Author(s):  
Min Cong Zhu ◽  
Wei Qi ◽  
Yan Jie Mao ◽  
Yin Hu ◽  
Xin Qing ◽  
...  
Keyword(s):  
Adsorption Property ◽  
Expanded Graphite ◽  
Freundlich Isotherm ◽  
Reactive Dye ◽  
Isotherm Model ◽  
Freundlich Isotherms ◽  
Pani Composite ◽  
Equilibrium Data ◽  
Langmuir Isotherm Model ◽  
Ir Analysis

In the present work, expanded graphite (EG) was prepared by microwave irradiation. Then, the expanded graphite/polyaniline (EG/PANi) composite was synthesized in the typical method. The samples of EG and EG/PANi were characterized by SEM and IR analysis techniques. Adsorption property of EG/PANi composite for removing the dye, reactive brilliant red K-2BP, from aqueous solution was investigated. The effects of initial dye concentration and contact time, pH, sorbent dosage on the adsorption process were studied. Experimental data were modelled by Langmuir and Freundlich isotherms. Langmuir isotherm model fitted well the equilibrium data for EG/PANi composite comparing to the Freundlich isotherm model. The uptake capacity of EG/PANi for K-2BP was found to be 1.03047 mg/g. The results indicated that EG/PANi composite is not an ideal sorbent used for reactive dye removal.

scholarly journals Clarification of Reprocessed Syrup and Use in the Formulation of Lollipop-Type Hard Candies

2020 ◽  
Vol 10 (6) ◽  
pp. 6846-6864
Keyword(s):  
Experimental Data ◽  
Activated Carbon ◽  
Sucrose Solution ◽  
Freundlich Isotherm ◽  
Adsorptive Capacity ◽  
Suitable Model ◽  
Distilled Water ◽  
Visual Evaluation ◽  
Freundlich Isotherms ◽  
Langmuir And Freundlich Isotherms

The objective was to evaluate the removal of dye using activated carbon, and apply the best condition in the removal of candy reprocessing syrup pigment, as well as to evaluate its influence in the visual aspect of a lollipop. Adsorption capacity tests were performed with the dye diluted with and without sucrose, and from the data, the linearization of the Langmuir and Freundlich isotherms were calculated. The lollipop was prepared with syrup treated with activated carbon and visually evaluated using a panel of untrained tasters. The Freundlich isotherm adjusted more appropriately to the experimental data of the adsorption of the dye diluted in distilled water, while for the dye diluted in sucrose solution, the most suitable model was Langmuir's. The experimental design condition showed the highest adsorptive capacity (26.91 mg.g-1) for the dye diluted in the aqueous solution was at a temperature of 60 ºC and pH 5.5, while for the sucrose-diluted dye solution, was 103.09 mg.g-1, under the same conditions. The visual evaluation of the lollipop indicated the possibility of adding up to 15% of reprocessing syrup. Thus, the use of activated carbon is an alternative to remove the coloring from candy syrup and enable its reuse within the industry.

scholarly journals Sorption of cationic dyes from aqueous solutions by moss Rhytidiadelphus squarrosus: Kinetics and equilibrium studies

2021 ◽  
Vol 9 (1) ◽  
pp. 53-62
Author(s):  
Lucia Remenárová ◽  
Martin Pipíška ◽  
Miroslav Horník ◽  
Jozef Augustín
Keyword(s):  
Aqueous Solutions ◽  
Low Cost ◽  
Freundlich Isotherm ◽  
Cationic Dyes ◽  
Order Kinetic ◽  
Natural Sorbent ◽  
Equilibrium Studies ◽  
Sorption Data ◽  
Maximum Sorption ◽  
Rhytidiadelphus Squarrosus

With the aim to investigate sorption properties of natural sorbent prepared from moss Rhytidiadelphus squarrosus we elucidated biosorption of cationic dyes Malachite green (BG4), Auramine O (BY2) and Thioflavine T (BY1) from aqueous solutions. The removal of dyes by moss biosorbent was found to be rapid at an initial stage and the equilibrium was reached within 1-2 hours. The pseudo-n-order kinetic model was successfully applied to the kinetic data and the order of adsorption reaction was calculated in the range from 1.7 to 2.6. The value of rate constant kn' ranged from 0.001 to 0.039 [min-1]/[μmol/g]1-n. The equilibrium data were fitted to the adsorption isotherms. The Freundlich isotherm was found to represent the measured sorption data of BG4, BY1 and BY2 well. The maximum sorption capacities of moss biomass from single dye solutions calculated by Langmuir equation were 354 μmol/g for BG4, 310 μmol/g for BY1 and 382 μmol/g for BY2. These results showed that the prepared biomass presents low-cost, natural and easy available sorbent which may be potentially used for removal of dyes from environment and also may be an alternative to more costly materials such as activated carbon.

Application of Chitosan Film for the Removal of Triclosan from Aqueous Solutions by Adsorption

2016 ◽  
Vol 675-676 ◽  
pp. 455-458
Author(s):  
Peeyanan Noirod ◽  
Jittapat Lamangthong ◽  
Padarat Ninjiaranai
Keyword(s):  
Aqueous Solutions ◽  
Contact Time ◽  
Chitosan Film ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Acidic Ph ◽  
Adsorption Efficiency ◽  
Freundlich Isotherms ◽  
Langmuir And Freundlich Isotherms ◽  
Equilibrium Data

The aim of this work was to study the adsorption efficiency of chitosan as an adsorbent for triclosan, commercially known as Irgasan, in aqueous solutions. The effects of contact time, pH and temperature were investigated using a batch adsorption technique. Langmuir and Freundlich isotherms were used to analyze the equilibrium data at different absorption conditions. The results showed that the maximum adsorption capacity for chitosan was found in the acidic pH 3 and at a temperature of 65 oC. These results suggested that chitosan can be used as an adsorbent for removal of triclosan from aqueous solutions.

scholarly journals Adsorption of U(VI) from Aqueous Solution onto Hydrotalcite-Like Compounds

2012 ◽  
Vol 9 (2) ◽  
pp. 669-679 ◽  
Author(s):  
Nguyen Van Suc
Keyword(s):  
Adsorption Capacity ◽  
Enthalpy Change ◽  
Time Dependent ◽  
Freundlich Isotherms ◽  
Langmuir And Freundlich Isotherms ◽  
Equilibrium Data ◽  
Endothermic Process ◽  
Ph Range ◽  
Initial Adsorption ◽  
Hydroxide Hydrate

Uranium adsorption by the synthesized compound of magnesium aluminum hydroxide hydrate – layered double hydrotalcite (STH)-like compounds was studied. The calcinated STH was proven to be a highly effective in U(VI) adsorption in pH range from 6.5 to 7. The time dependent experimental data were found to be fit to the pseudo-second-oder model. The equilibrium data have been modeled using Langmuir and Freundlich isotherms. The results showed that both model provide the best correlation with equilibrium data. The highest adsorption capacity, approximated 62.5 mg/g, was observed in the calcinated STH at 500 °C. The positive value of enthalpy change indicated that adsorption reaction of U(VI) on STH was endothermic process. The regeneration experiments of STH using 0.1M Na2CO3solution was successfully demonstrated multiple times without any significant effect on the initial adsorption capacity.

Adsorption of Copper Ions from Aqueous Solutions by Chitin

2012 ◽  
Vol 550-553 ◽  
pp. 2424-2427
Author(s):  
Chung Hsin Wu ◽  
Chao Yin Kuo ◽  
Meng Jia Chen
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Linear Correlation ◽  
Langmuir Isotherm ◽  
Copper Ions ◽  
Correlation Coefficients ◽  
Freundlich Isotherm ◽  
Freundlich Isotherms ◽  
Langmuir And Freundlich Isotherms ◽  
Better Than

This study utilizes chitin to remove dissolved Cu(II) from aqueous solutions. The effects of the dissolved Cu(II) concentration, chitin dosage, and pH on adsorption of dissolved Cu(II) by chitin are determined. Adsorption capacity for 20 and 80 mg/L dissolved Cu(II) onto chitin (2 g/L) was 3.86 mg/g and 5.12 mg/g, respectively. The dissolved Cu(II) adsorption percentage increased from 39% to 70% when the chitin dosage was increased from 2 g/L to 4 g/L. The linear correlation coefficients of Langmuir and Freundlich isotherms were obtained. Analytical results demonstrate that the Freundlich isotherm fitted experimental results better than did the Langmuir isotherm. Enthalpy (ΔH0) and entropy (ΔS0) for dissolved Cu(II) adsorption were 8.46 kJ/mol and 123.1 J/mol.K, respectively.

scholarly journals Cr(VI) Removal from Wastewater by Using Rice Husk Ash (RHA)

2006 ◽  
Vol 6 (1) ◽  
pp. 53
Author(s):  
M. J. Uddin ◽  
M. M.R. Khan ◽  
M S. Iftekhar ◽  
M A Islam
Keyword(s):  
Rice Husk ◽  
Optimum Parameter ◽  
Rice Husk Ash ◽  
Toxic Metal ◽  
Synthetic Wastewater ◽  
Tannery Effluent ◽  
Freundlich Isotherms ◽  
Chromium Vi ◽  
Langmuir And Freundlich Isotherms ◽  
Equilibrium Data

Rice husk ash (RHA) was studied as a potential adsorbent for Chromium (VI)removal from wastewater. RHA was able to remove effectively and economically toxic metal from synthetic wastewater. Experiments were done on the removal of Cr(VI) from dichromate solution which is a form of chromium in tannery effluent. The amount of Cr(VI) adsorption increased with the decrease in pH. The optimum parameter was = 2.0 evaluated at pH and the dose rate of the adsorbent was 5 kg RHNm3. The equilibrium data fit well in both the Langmuir and Freundlich isotherms. The study showed that 89.29 x 10-3kg Cr(VI) could be removed by 1 Kg of RHA. Since rice husk (RH) is available and cheap in Bangladesh, it can be used easily as an appropriate adsorbent to remove more than 95% Cr(VI) from tannery wastewater.

scholarly journals Role of Sawdust in the Removal of Iron from Aqueous Solution

2017 ◽  
Vol 23 (3) ◽  
pp. 223 ◽  
Author(s):  
H.B. Senin ◽  
O. Subhi ◽  
R. Rosliza ◽  
N. Kancono ◽  
M.S. Azhar ◽  
...  
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Langmuir Isotherm ◽  
Room Temperature ◽  
Freundlich Isotherm ◽  
Batch Test ◽  
Freundlich Isotherms ◽  
Langmuir And Freundlich Isotherms ◽  
Better Than

Sawdust, inexpensive material has been utilized as an absorbent for the removal of iron from aqueous solution for their safe disposal. The adsorption experiments of untreated sawdust (SD) and treated sawdust (SDC) have been carried out at room temperature using the batch test. The Langmuir and Freundlich isotherms were used to observe sorption phenomena of sawdust in the removal of iron. The results indicate that the sawdust was capable in removing iron in aqueous solution. The results have shown that the Langmuir isotherm was found well fitted into the experimental data as compared to the Freundlich isotherm. It was found that, chemisorptions and physisorption were the prime mechanism for the process of adsorption to occur between the sawdust and iron. The results also proved that the acid sulphuric treated sawdust is much better than that of untreated sawdust as an adsorbent for iron.

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