scholarly journals Adsorption of Congo, Red Rhodamine B and Disperse Blue Dyes From Aqueous Solution onto Raw Flint Clay

2012 ◽  
Vol 9 (4) ◽  
pp. 680-688 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Rhodamine B ◽  
Congo Red ◽  
Water Solution ◽  
Diffusion Mechanism ◽  
Batch Adsorption ◽  
Kinetic Measurements ◽  
Equilibrium Data ◽  
Rate Kinetics ◽  
Kinetic Investigations ◽  
Gibb’S Free Energy

Removal of Congo red, Rhodamine B, and Dispers Blue dyes from water solution have been achieved using Flint Clay as an adsorbent. The adsorption was studied as a function of contact time, adsorbent dose, pH, and temperature under batch adsorption technique. The equilibrium data fit with Langmuir, Freundlich and Toth models of adsorption and the linear regression coefficient R2 was used to elucidate the best fitting isotherm model. Different thermodynamic parameters, namely Gibb’s free energy, enthalpy and entropy of the on-going adsorption process have also been evaluated. Batch technique has been employed for the kinetic measurements and the adsorption of the three dyes follows a second order rate kinetics. The kinetic investigations also reveal that intraparticle diffusion mechanism was operative

Direct Yellow 8 Azo Removal by Bentonite Clay Solution: Experimental and Theoretical Studies

2021 ◽  
Vol 19 (5) ◽  
pp. 120-131
Author(s):  
Sanaa Tareq ◽  
Masar Ali Awad ◽  
Khawla Kani Jasim ◽  
Shahad Kadhim Taher ◽  
Mustafa M. Kadhim
Keyword(s):  
Density Functional ◽  
Water Solution ◽  
Bentonite Clay ◽  
Kinetic Studies ◽  
Batch Adsorption ◽  
Total Electron Density ◽  
Total Electron ◽  
Equilibrium Data ◽  
Gibb’S Free Energy ◽  
Kinetic Calculations

In the theoretical part, removal of direct yellow 8 (DY8) from water solution was accomplished using Bentonite Clay as an adsorbent. Under batch adsorption, the adsorption was observed as a function of contact time, adsorbent dosage, pH, and temperature. The equilibrium data were fitted with the Langmuir and Freundlich adsorption models, and the linear regression coefficient R2 was used to determine the best fitting isotherm model. thermodynamic parameters of the ongoing adsorption mechanism, such as Gibb's free energy, enthalpy, and entropy, have also been measured. The batch method was also used for the kinetic calculations, and the day's adsorption assumes first-order rate kinetics. The kinetic studies also show that the intraparticle diffusion process was active. Density Functional Theory (DFT) was used to study the dye structure with Gaussian 09 and predict the active site in a molecule using total electron density (TED) and electrostatic surface potential (ESP).

scholarly journals Adsorption of Congo Red Dye from Aqueous Solution onto Natural and Modified Bauxite Clays

2017 ◽  
Vol 14 (1) ◽  
pp. 167-180 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Congo Red ◽  
Batch Adsorption ◽  
General Shape ◽  
Congo Red Dye ◽  
Before And After ◽  
Equilibrium Data ◽  
Best Fitting ◽  
Enthalpy And Entropy ◽  
Gibb’S Free Energy ◽  
Red Dye

The adsorption behavior of congo red dye from its aqueous solutions was investigated onto natural and modified bauxite clays. Both bauxite and modified bauxite are primarily characterized by using, FTIR, SEM, AFM, and XRD. Several variables are studied as a function of adsorption including contact time, adsorbent weight, pH, ionic strength, particle size and temperature under batch adsorption technique. The absorbance of the solution before and after adsorption was measured spectrophotometrically. The equilibrium data fit with Langmuir model of adsorption and the linear regression coefficient R2 is found to be 0.9832 and 0.9630 for natural and modified bauxite respectively at 37.5°C which elucidate the best fitting isotherm model. The general shape of the adsorption isotherm of congo red on natural and modified bauxite is consistent with (H-type) on the Giles classification. Different thermodynamic parameters such as Gibb's free energy, enthalpy and entropy of the on-going adsorption process have also been evaluated. The thermodynamic analyses of the congo red adsorption on natural and modified bauxite indicate that the systems are endothermic in nature

scholarly journals Experimental investigation of titanium dioxide as an adsorbent for removal of Congo red from aqueous solution, equilibrium and kinetics modeling

2020 ◽  
Vol 10 (3) ◽  
pp. 251-266
Author(s):  
Moussa Abbas
Keyword(s):  
Titanium Dioxide ◽  
Congo Red ◽  
Active Sites ◽  
Batch Adsorption ◽  
Physical Parameters ◽  
Solution Interface ◽  
Initial Ph ◽  
Equilibrium And Kinetics ◽  
Equilibrium Data ◽  
Pseudo Second Order

Abstract The adsorption of Congo red onto titanium dioxide (TiO2) material has been investigated at batch conditions. The effects of contact time (0–60 min), initial pH (3–11), agitation speed (100–500 rpm), temperature (298–343 K), adsorbent dosage (0.5–2 g/L), and Congo red concentration (5–15 mg/L) on the Congo red adsorption by TiO2 have been studied. The kinetic parameters, rate constants, and equilibrium adsorption capacities were calculated and discussed for each kinetic model. The adsorption of Congo red onto TiO2 is well described by the pseudo-second order equation. The adsorption isotherm follows the Langmuir model, providing a better fit of the equilibrium data. The batch adsorption experiments were carried out to optimize the physical parameters on the Congo red removal efficiency. It has been found that 152 mg/g at 25 °C is removed. The thermodynamic parameters indicate the spontaneous and endothermic nature of the adsorption process with activation energy (Ea) of −64.193 kJ/mol. The positive value of the entropy (ΔS°) clearly shows that the randomness is decreased at the solid–solution interface during the Congo red adsorption onto TiO2, indicating that some structural exchange may occur among the active sites of the adsorbent and the ions.

scholarly journals Silica Monolith for the Removal of Pollutants from Gas and Aqueous Phases

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1316
Author(s):  
Vanessa Miglio ◽  
Chiara Zaccone ◽  
Chiara Vittoni ◽  
Ilaria Braschi ◽  
Enrico Buscaroli ◽  
...  
Keyword(s):  
Rhodamine B ◽  
Water Solution ◽  
Synthesis Method ◽  
Textural Properties ◽  
Adsorption Properties ◽  
Water Soluble ◽  
Silica Monoliths ◽  
Physico Chemical ◽  
Gaseous Toluene ◽  
Mcm 41

This study focused on the application of mesoporous silica monoliths for the removal of organic pollutants. The physico-chemical textural and surface properties of the monoliths were investigated. The homogeneity of the textural properties along the entire length of the monoliths was assessed, as well as the reproducibility of the synthesis method. The adsorption properties of the monoliths for gaseous toluene, as a model of Volatile Organic Compounds (VOCs), were evaluated and compared to those of a reference meso-structured silica powder (MCM-41) of commercial origin. Silica monoliths adsorbed comparable amounts of toluene with respect to MCM-41, with better performances at low pressure. Finally, considering their potential application in water phase, the adsorption properties of monoliths toward Rhodamine B, selected as a model molecule of water soluble pollutants, were studied together with their stability in water. After 24 h of contact, the silica monoliths were able to adsorb up to the 70% of 1.5 × 10−2 mM Rhodamine B in water solution.

Preparation of a magnetically separable CoFe2O4supported Ag nanocatalyst and its catalytic reaction towards the decolorization of a variety of dyes

RSC Advances ◽  
2015 ◽  
Vol 5 (50) ◽  
pp. 40193-40198 ◽  
Author(s):  
Bhanudas Naik ◽  
Subhenjit Hazra ◽  
Dayananda Desagani ◽  
Barun Kumar Ghosh ◽  
Manoj Kumar Patra ◽  
...  
Keyword(s):  
Rhodamine B ◽  
Catalytic Reaction ◽  
Ag Nanoparticles ◽  
Congo Red ◽  
Magnetically Separable

CoFe2O4supported Ag nanoparticles were investigated as a catalyst for the decolorization of 4-nitrophenol, Congo red, rhodamine B and dye mixtures.

scholarly journals Zero-Cost Agricultural Wastes as Sources for Activated Carbons Synthesis: Lead Ions Removal from Wastewaters

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 652 ◽  
Author(s):  
George Z. Kyzas ◽  
Athanasios C. Mitropoulos
Keyword(s):  
Activated Carbons ◽  
Freundlich Isotherm ◽  
Lead Ions ◽  
Isotherm Models ◽  
Activation Process ◽  
Strong Impact ◽  
Equilibrium Data ◽  
Preparation Route ◽  
Temperature Equilibrium ◽  
Gibb’S Free Energy

In the present study, activated carbons (PAC) were hydrothermally prepared with an environmental friendly preparation route after pyrolysis from biomass (specifically from agricultural (potato) peels). The prepared biochars were activated with potassium hydroxide (chemical activities). The preparation route had a strong impact on the pore structure of PAC. In addition, surface chemistry was also affected by the preparation and activation process. The adsorbent materials were also characterized by Scanning Electron Microscopy. The prepared activated carbons were used as adsorbents for the removal of lead ions. Batch experiments were performed to investigate the effect of physico-chemical parameters, such as pH, contact time, initial metal concentration and temperature. Equilibrium data were analyzed using Langmuir and Freundlich isotherm models. The thermodynamic parameters such as the change of enthalpy (ΔH0), entropy (ΔS0) and Gibb’s free energy (ΔG0) of adsorption systems were also determined and evaluated.

Theoretical Rate Evaluation of Gas Phase Atmospheric Ozone Reactions

2011 ◽  
Vol 367 ◽  
pp. 849-852
Author(s):  
A.I. Igbafe ◽  
O.F. Omobude
Keyword(s):  
Rate Constant ◽  
Theory Model ◽  
State Theory ◽  
Molecular Structures ◽  
Energy Of Activation ◽  
Enthalpy Of Reaction ◽  
Equilibrium Data ◽  
Gibb’S Free Energy ◽  
Rate Evaluation ◽  
Structural Methods

The rate of transformation of ozone in the troposphere over a temperature range of-100°C and +100°C has been established. Tropospheric ozone with the quality of a strong oxidizing agent, is secondary pollutant species associated with the initiation of numerous chemical reactions in the atmosphere. In this study, a theoretical approach utilized Gibb’s free energy of reaction and enthalpy of reaction in transition state theory model equations to generate chemical equilibrium data and consequently reaction kinetic parameters. The thermochemical properties were obtained using electronic structural methods of the quantum mechanics computational chemistries which approximates the Schrödinger equation. The model chemistry methods were evaluated using the GuassView for generating molecular structures of species and the Gaussian 03 (G03) package for energy computation. The study revealed that the most relevant of the reactions considered was that involving NO with a rate constant of 7.39 x 1011 s-1 and energy of activation (EA/R) of-216.98 K while the least involved HS* with rate constant of 9.56 x 1069 s-1 and energy of activation (EA/R) of-202.95 K.

scholarly journals Efficient Congo Red Removal Using Porous Cellulose/Gelatin/Sepiolite Gel Beads: Assembly, Characterization, and Adsorption Mechanism

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3890
Author(s):  
Chenlu Jiao ◽  
Die Liu ◽  
Nana Wei ◽  
Jiannan Gao ◽  
Fan Fu ◽  
...  
Keyword(s):  
Congo Red ◽  
Adsorption Mechanism ◽  
Batch Adsorption ◽  
Order Kinetic ◽  
Dye Wastewater ◽  
Step Method ◽  
Gel Beads ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Highly Porous

Porous sustainable cellulose/gelatin/sepiolite gel beads were fabricated via an efficient ‘hydrophilic assembly–floating droplet’ two-step method to remove Congo red (CR) from wastewater. The beads comprised microcrystalline cellulose and gelatin, forming a dual network framework, and sepiolite, which acted as a functional component to reinforce the network. The as-prepared gel beads were characterized using FTIR, SEM, XRD, and TGA, with the results indicating a highly porous structure that was also thermally stable. A batch adsorption experiment for CR was performed and evaluated as a function of pH, sepiolite addition, contact time, temperature, and initial concentration. The kinetics and isotherm data obtained were in agreement with the pseudo-second-order kinetic model and the Langmuir isotherm, with a maximum monolayer capacity of 279.3 mg·g−1 for CR at 303 K. Moreover, thermodynamic analysis demonstrated the spontaneous and endothermic nature of the dye uptake. Importantly, even when subjected to five regeneration cycles, the gel beads retained 87% of their original adsorption value, suggesting their suitability as an efficient and reusable material for dye wastewater treatments.

scholarly journals Fabrication of Novel Valorized Ecofriendly Olive Seed Residue/anthracite/chitosan Composite for Removal of Cr (Vi): Kinetics, Isotherms and Thermodynamics Modeling

2021 ◽  
Author(s):  
M R. El-Aassar ◽  
F. M. Mohamed ◽  
I. H. Alsohaimia ◽  
R E. Khalifa
Keyword(s):  
Low Cost ◽  
Operating Conditions ◽  
Batch Adsorption ◽  
Adsorption Mode ◽  
Adsorption Affinity ◽  
Equilibrium Data ◽  
Isotherms And Thermodynamics ◽  
Olive Seed ◽  
Ft Ir ◽  
Thermodynamics Modeling

Abstract The present work verified the adsorption of hexavalent chromium (Cr (VI)) from synthetic aqueous solution using synthesized highly efficient low-cost adsorbent prepared from H2O2-modified olive seed residue solid waste/Anthracite/Chitosan (MOSR/An/CS) composite. Characteristics of the fabricated MOSR/An/CS composite were estimated by XRD, SEM, TGA, DSC, FT-IR, SBET and zeta potential tools. The entire chromium uptake study was conducted via batch adsorption mode under various operating conditions. Kinetics data were analyzed using five kinetic models, while empiric equilibrium data was fitted using three isotherms. The results clarified that Langmuir best described the adsorption of Cr (VI) ions with maximum monolayer coverage of 137.7 mg/g. Pseudo-first-order mode was nicely fitted the kinetics adsorption. Further, Elovich, intraparticle diffusion and Boyd models validates that more than one mechanism was contributed to the adsorption of Cr (VI). Besides, the estimated activation energy (Ea) and enthalpy (ΔH°) suggest the physical and endothermic nature of the adsorption process. The developed MOSR/An/Cs composite exhibited decent reusability after five sequential adsorption cycles and showed higher adsorption affinity towards Cr (VI) ions. MOSR / An / Cs composite could also be effectively used as an effective eco-friendly and recyclable sorbent for the elimination of Cr (VI) from wastewater.

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