The Kinetics and Equilibrium Thermodynamics Study on the Removal of Direct Blue and Titan Yellow Dyes from Aqueous Media by Modified Rice Husk Char

2020 ◽  
Vol 234 (3) ◽  
pp. 485-503
Author(s):  
Abdul Malik ◽  
Abbas Khan ◽  
Nasrullah Shah ◽  
Muhammad Sufaid Khan
Keyword(s):  
Rice Husk ◽  
Adsorption Process ◽  
Aqueous Media ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
X Rays ◽  
Experimental Conditions ◽  
Titan Yellow ◽  
Direct Blue

AbstractThe use of indigenous natural materials and their modification toward fruitful application is one of the important subjects. Thermal modification of Rice Husk at 400 oC resulted into Rice Husk Char (RHC) which was chemically modified with KOH and was labeled as KOH Modified Rice Husk Char (KMRHC). Both RHC and KMRHC were characterized by using, Fourier transformed infrared (FTIR), scanning electron microscopy (SEM), energy dispersive X-rays (EDX) and X-ray diffraction (XRD) before and after their use as adsorbents. The prepared material was applied for the removal of toxic dyes, Direct Blue (DB) and Titan Yellow (TY) from aqueous media. The maximum adsorption capacity of DB and TY dyes on KMRHC were inspected as 30.9 mg/g and 28.6 mg/g, respectively at pH 4 using initial dye concentrations of 80 mg/L containing 2500 mg/L of the adsorbent dose with agitation speed of 240 rpm at 303 K. At the same experimental conditions the highest percentage removal of DB and TY on the adsorbent were observed as 96.6% and 89.3%, respectively. Thermodynamics studies of the adsorption of DB and TY dyes on KMRHC inferred for exothermic and spontaneous process. The value of ΔS is negative which suggested that randomness decreases at the interface of adsorbent-adsorbate during the adsorption. The kinetics study indicated that the experimental data of the adsorption process for both dyes, best fits to pseudo-second order kinetic model. The equilibrium data was tested on Langmuir, Freundlich and Temkin adsorption isotherm models. It was observed that the data are best fit to the Langmuir isotherm model (R2 > 0.99), which suggested that the adsorption process is dominated by chemisorption approach. The overall results suggest that various parameters of the adsorption process were not only affected by the variation in experimental conditions but also by the chemical structure of the adsorbate molecules for the same adsorbent.

Preparation and Chemical Modification of Rice Husk Char for the Removal of a Toxic Dye (Orange G) from Aqueous Medium

2019 ◽  
Vol 233 (3) ◽  
pp. 375-392 ◽  
Author(s):  
Abdul Malik ◽  
Abbas Khan ◽  
Muhammad Humayun
Keyword(s):  
Rice Husk ◽  
Adsorption Process ◽  
Aqueous Media ◽  
Effect Of Temperature ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Experimental Conditions ◽  
Orange G ◽  
Adsorbent Dose

Abstract The rice husk char (RHC) was prepared by keeping a known amount of the rice husk in furnace at 400°C. The product was modified with KOH and labeled as KOH modified rice husk char (KMRHC) which was used as an adsorbent for the removal of toxic dye, Orange G (OG) from aqueous media. Variation in the experimental conditions (agitation time, dye concentration, adsorbent dose, pH and temperature) play significant role in the adsorption process. The maximum adsorption capacity of OG on KMRHC was investigated as 38.8 mg/g at pH=4 using initial dye concentrations of 80 mg/L containing 2 g/L of the adsorbent dose with agitation speed of 250 rpm at 303 K. The % adsorption of dye was inspected as 96%. Thermodynamics studies of the adsorption of OG on KMRHC indicated that the value of ΔG and ΔH were negative which revealed that the adsorption process is exothermic and spontaneous process. The negative value of ΔS suggested that randomness decreases at the interface of adsorbent–adsorbate during the adsorption process. The kinetics study indicated that the experimental data of the adsorption process best fits to pseudo-second order kinetic model. The equilibrium data was tested on Langmuir, Freundlich and Temkin adsorption isotherm models. It was inspected that data follows all the three isotherm models (R2>0.91). However, the values of correlation coefficients (R2) indicated that the data is best fit to the Langmuir isotherm model (R2>0.99) which suggest for chemi-sorption process. The effect of temperature (303–343 K) shows that by varying the temperature the adsorption process is significantly affected. The general trend indicates that adsorption efficiency is higher at lower temperature as compared to higher temperature. This trend also suggests that the adsorption coefficient (K), rate of adsorption, and hence the spontaneity of adsorption process also decreases with raising the temperature.

scholarly journals Adsorption of Basic and Acidic Dyes onto Agricultural Wastes

2016 ◽  
Vol 70 ◽  
pp. 12-26 ◽  
Author(s):  
Nnaemeka John Okorocha ◽  
J. Josphine Okoji ◽  
Charles Osuji
Keyword(s):  
Adsorption Capacity ◽  
Contact Time ◽  
Adsorption Process ◽  
Aqueous Media ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Thermodynamic Quantities ◽  
Order Kinetic ◽  
Dyes Adsorption ◽  
Adsorbent Dose

The potential of almond leaves powder, (ALP) for the removal of Crystal violet (CV) and Congo red (CR) dyes from aqueous solution was investigated. The adsorbent (ALP) was characterized by FTIR and SEM analysis. Batch adsorption studies were conducted and various parameters such as contact time, adsorbent dosage, initial dye concentration, pH and temperature were studied to observe their effects in the dyes adsorption process. The optimum conditions for the adsorption of CV and CR dyes onto the adsorbent (ALP) was found to be: contact time (100mins), pH (10.0), temperature (343K) for an initial CV dye concentration of 50mg/L using adsorbent dose of 1.0g and contact time (100mins), pH (2.0), temperature (333K) for an initial CR dye concentration of 50mg/L using adsorbent dose 1.0g respectively. The experimental equilibrium adsorption data fitted best and well to the Freundlich isotherm model for both CV and CR dyes adsorption. The maximum adsorption capacity of ALP was found to be 22.96mg/g and 7.77mg/g for the adsorption of CV and CR dyes respectively. The kinetic data conformed to the pseudo-second-order kinetic model. Thermodynamic quantities such as Gibbs free energy (ΔG0), enthalpy (ΔH0) and entropy (ΔS0) were evaluated and the negative values of ΔG0obtained for both dyes indicate the spontaneous nature of the adsorption process while the positive values of ΔH0and ΔS0obtained indicated the endothermic nature and increased randomness during the adsorption process respectively for the adsorption of CV and CR onto ALP. Based on the results obtained such as good adsorption capacity, rapid kinetics, and its low cost, ALP appears to be a promising adsorbent material for the removal of CV and CR dye stuff from aqueous media.

scholarly journals Application of Modified Agricultural Waste in the Adsorption of Bromocresol Green Dye

2020 ◽  
pp. 15-24
Author(s):  
Onu Chijioke Elijah ◽  
Oguanobi Nonso Collins ◽  
Okonkwo Callistus Obumneme ◽  
Nnamdi-Bejie Jessica
Keyword(s):  
Activated Carbon ◽  
Rice Husk ◽  
Contact Time ◽  
Adsorption Process ◽  
Research Work ◽  
Isotherm Models ◽  
Bromocresol Green ◽  
Order Kinetic ◽  
Adsorptive Removal ◽  
Kinetics Of

Background: The adsorptive removal of anionic dye (Bromocresol green) from aqueous solution was investigated using activated carbon prepared from rice husk. Place of Study: The research work took place at Nnamdi Azikiwe Univeristy Awka, Nigeria. Methods: The rice husk which was obtained from rice mills in Awka was activated with tetraoxophosphoric acid and carbonized in a furnace. The adsorption process was investigated by varying the contact time, temperature, dosage, pH and initial concentration in a batch process. Five isotherm models (Langmuir, Freundlich, Temkin, Halsay and Harkin-Jura) were employed in the equilibrium studies. Thermodynamics and kinetics of the adsorption were carried out. Results: The result indicated that increase in contact time, adsorbent dosage and temperature increased the percent uptake of the Bromocresol green dye. Maximum percentage adsorption of about 93% was obtained. Langmuir and Harkin-Jura isotherm models best described the equilibrium data of the adsorption process. Pseudo second-order kinetic model best correlates the kinetics of the experimental data. The thermodynamic study showed that the Gibbs free energy (ΔG), enthalpy change (ΔH) and entropy change (ΔS) were –2.541 kJ/mol,  -7.401 kJ/mol and –15.52 kJ/mol K respectively. Conclusion: This work has shown that activated carbon prepared from rice husk can be used in adsorptive removal of bromocresol green dye from solution and that the adsorption process was spontaneous and exothermic.

Preparation of novel porous Al2O3-SiO2 nanocomposites via solution-freeze-drying-calcination method for the efficient removal of uranium in solution

2021 ◽  
Author(s):  
Maoling Wu ◽  
Ling Ding ◽  
Jun Liao ◽  
Yong Zhang ◽  
Wenkun Zhu
Keyword(s):  
Adsorption Process ◽  
Interaction Mechanism ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Calcination Method ◽  
Adsorption Desorption

Abstract In this work, the efficient extraction of uranium in solution using Al2O3-SiO2-T was reported. Kinetics and isotherm models indicated that the removal process of uranium onAl2O3-SiO2-T accorded with pseudo-second-order kinetic model and Langmuir isotherm model, which showed that the adsorption process was a uniform mono-layer chemical behavior. The maximum adsorption capacity of Al2O3-SiO2-T reached 738.7 mg g-1, which was higher than AlNaO6Si2 (349.8 mg g-1) and Al2O3-SiO2-NT (453.1 mg g-1), indicating that the addition of template could effectively improve the adsorption performance of Al2O3-SiO2 to uranium. Even after five cycles of adsorption-desorption, the removal percentage of uranium on Al2O3-SiO2-T remained 96%. Besides, the extraction efficiency of uranium on Al2O3-SiO2-T was 72.5% in simulated seawater, which suggested that the Al2O3-SiO2-T was expected to be used for uranium extraction from seawater. Further, the interaction mechanism between Al2O3-SiO2-T and uranium species was studied. The results showed that the electrostatic interaction and complexation played key roles in the adsorption process of Al2O3-SiO2-T to uranium.

scholarly journals Cr6+ adsorption by modified vermiculite

2020 ◽  
Author(s):  
Valeria Medoro ◽  
Celia Marcos Pascual ◽  
Giacomo Ferretti ◽  
Giulio Galamini ◽  
Massimo Coltorti
Keyword(s):  
Earth Sciences ◽  
Inductively Coupled Plasma ◽  
Contact Time ◽  
Second Order ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Experimental Conditions ◽  
X Ray ◽  
Pseudo Second Order

<p><strong>Abstract</strong>: <strong>Cr<sup>6+</sup> adsorption by modified vermiculite</strong></p><p><strong> </strong></p><p>Valeria Medoro- University of Ferrara , Department of Physics and Earth Sciences, Italy</p><p>Celia Marcos Pascual-University of Oviedo, Department of Geology, Spain</p><p>Giacomo Ferretti- University of Ferrara , Department of Physics and Earth Sciences, Italy</p><p>Giulio Galamini- University of Ferrara , Department of Physics and Earth Sciences, Italy</p><p>Massimo Coltorti- University of Ferrara , Department of Physics and Earth Sciences, Italy</p><p> </p><p>This work aimed at investigating the adsorption of Cr<sup>6+</sup> in water by exfoliated vermiculite. The adsorbant tested in this experiment was a vermiculite (from China) which has been subjected to heating at 1000 °C for 1 minute, resulting in an exfoliated vermiculite.</p><p>Three effects were studied: 1) contact time; 2) initial concentracion of Cr<sup>6+</sup>; 3) adsorbent mass. Samples were analysed by X Ray Fluorescence (XRF), X Ray Diffraction (XRD) and the solutions with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to quantify the adsorbed Cr<sup>6+</sup> by the vermiculite.</p><p>Results from XRD diffraction showed a conversion of vermiculite into flogopite  after heating at 1000°C for 1 minute because of: 1) high content of potassium, 2) dehydration and 3) structural re-ordering; after the contact of vermiculite with Cr<sup>6+</sup>, the mineral structure did not change. The adsorption of Cr<sup>6+</sup> was studied by Langmuir, Freundlich and Dubinin-Kaganer-Radushkevich (DKR) isotherm models. DKR model, indicative of a cooperative process, described adsorption equilibrium better than the other two models and the maximum adsorption capacity obtained was of 2.81 mol/g. Kinetic was studied using pseudo-first and pseudo-second order kinetic models, with a better description of the process by pseudo-second order model with correlation coefficient almost unitary (R<sup>2</sup>=0.9984; other kinetic parameters were k<sub>2</sub>=0.0015 and the absorption initial rate of 0.2x10<sup>-8</sup> mg g<sup>-1</sup> h<sup>-1</sup>). </p><p>The present study demonstrates the effectiveness of modified vermiculite adsorbents for the treatment of hexavalent chromium-contaminated waters and that its adsorption depends on the experimental conditions (such as contact time, initial concentracion of Cr<sup>6+</sup> and adsorbent mass).</p>

scholarly journals Comparative Biosorption Studies of Hexavalent Chromium Ion onto Raw and Modified Palm Branches

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Mona A. Shouman ◽  
Nady A. Fathy ◽  
Soheir A. Khedr ◽  
Amina A. Attia
Keyword(s):  
Adsorption Process ◽  
Isotherm Models ◽  
Ammonium Bromide ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Chemically Modified ◽  
Chromium Vi ◽  
Adsorption Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The waste of palm branches (PB) was tested for its ability to remove chromium (VI) from aqueous solution by batch and column experiments. Palm branches chemically modified with an oxidizing agent (sulphuric acid) then coated with chitosan and surfactant (hexadecyl trimethyl ammonium bromide surfactant, HDTMA), respectively, were carried out to improve the removal performance of PB. The results of their Cr (VI) removal performances are pH dependent. The adsorption data could be well interpreted by the Langmuir, Freundlich, and Flory-Huggins isotherm models. The maximum adsorption capacity obtained from the Langmuir model for the chitosan coated oxidized palm branches is 55 mg/mg. The adsorption process could be described by pseudo-second-order kinetic model. The intraparticle diffusion study revealed that film diffusion might be involved. The biosorbents were successfully regenerated using 1 M HCL solution.

Utilisation of Biomass and Hybrid Biochar from Elephant Grass and Low Density Polyethylene for the Competitive Adsorption of Pb(II), Cu(II), Fe(II) and Zn(II) from Aqueous Media

2020 ◽  
Vol 13 ◽  
Author(s):  
Joshua O. Ighalo ◽  
Lois T. Arowoyele ◽  
Samuel Ogunniyi ◽  
Comfort A. Adeyanju ◽  
Folasade M. Oladipo-Emmanuel ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Removal Efficiency ◽  
Contact Time ◽  
Competitive Adsorption ◽  
Adsorption Process ◽  
Aqueous Media ◽  
Polluted Water ◽  
Batch Adsorption ◽  
Order Kinetic ◽  
Elephant Grass

Background: The presence of pollutants in polluted water is not singularized hence pollutant species are constantly in competition for active sites during the adsorption process. A key advantage of competitive adsorption studies is that it informs on the adsorbent performance in real water treatment applications. Objective: This study aims to investigate the competitive adsorption of Pb(II), Cu(II), Fe(II) and Zn(II) using elephant grass (Pennisetum purpureum) biochar and hybrid biochar from LDPE. Method: The produced biochar was characterised by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The effect of adsorption parameters, equilibrium isotherm modelling and parametric studies were conducted based on data from the batch adsorption experiments. Results: For both adsorbents, the removal efficiency was >99% over the domain of the entire investigation for dosage and contact time suggesting that they are very efficient for removing multiple heavy metals from aqueous media. It was observed that removal efficiency was optimal at 2 g/l dosage and contact time of 20 minutes for both adsorbent types. The Elovich isotherm and the pseudo-second order kinetic models were best-fit for the competitive adsorption process. Conclusion: The study was able to successfully reveal that biomass biochar from elephant grass and hybrid biochar from LDPE can be used as effective adsorbent material for the removal of heavy metals from aqueous media. This study bears a positive implication for environmental protection and solid waste management.

Ouricuri (Syagrus coronata) fiber: a novel biosorbent to remove methylene blue from aqueous solutions

2016 ◽  
Vol 75 (1) ◽  
pp. 106-114 ◽  
Author(s):  
Lucas Meili ◽  
Társila Santos da Silva ◽  
Daniely Carlos Henrique ◽  
João Inácio Soletti ◽  
Sandra Helena Vieira de Carvalho ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Experimental Design ◽  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Adsorption Process ◽  
Fiber Diameter ◽  
Aqueous Media ◽  
Process Efficiency ◽  
Maximum Adsorption Capacity ◽  
Equilibrium Studies

In this work, the potential of ouricuri (Syagrus coronata) fiber as a novel biosorbent to remove methylene blue (MB) from aqueous solutions was investigated. The fiber was prepared and characterized according to the fundamental features for adsorption. A 23 experimental design was used to evaluate the effects of adsorbent dosage (M), fiber diameter (D) and agitation (A) on the adsorption capacity. In the more adequate conditions, kinetic and equilibrium studies were performed. The experimental design results showed that M = 10 g L−1), D = 0.595 mm and A = 200 rpm were the more adequate conditions for MB adsorption. Based on the kinetic study, it was found that the adsorption process was fast, being the equilibrium was attained at about 5 min, with 90% of color removal. The isotherm was properly represented by the Sips model, and the maximum adsorption capacity was 31.7 mg g−1. In brief, it was demonstrated that ouricuri fiber is an alternative biosorbent to remove MB from aqueous media, taking into account the process efficiency and economic viewpoint.

scholarly journals Phenol adsorption from wastewater using cashew nut shells as adsorbent

2018 ◽  
Vol 7 (3) ◽  
pp. 966
Author(s):  
Kartik Kulkarni ◽  
Varsha Sudheer ◽  
C R Girish
Keyword(s):  
Agricultural Waste ◽  
Freundlich Isotherm ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Multilayer Adsorption ◽  
Phenol Adsorption ◽  
Cashew Nut ◽  
Experimental Parameters ◽  
Order Kinetic Model

The potential of agricultural waste cashew nut shells as an adsorbent for removing phenol from wastewater is presented in this paper. The adsorbent was treated with 3M sulphuric acid in order to improve the properties. The experimental parameters such as adsorbent dosage, concentration and temperature were optimized with response surface methodology (RSM). The isotherm data were tested with different isotherm models and it obeyed Freundlich Isotherm showing the multilayer adsorption. The kinetic data satisfied pseudo-first order kinetic model. The maximum adsorption capacity was calculated to be 35.08 mg/g proving the capability of cashew nut shells for removing phenol from wastewater.  

scholarly journals Effective Removal of Malachite Green from Aqueous Solutions Using Magnetic Nanocomposite: Synthesis, Characterization, and Equilibrium Study

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Ali Q. Alorabi
Keyword(s):  
Surface Area ◽  
Malachite Green ◽  
Chemical Activation ◽  
Aqueous Media ◽  
Kinetic Studies ◽  
Cost Effective ◽  
Magnetic Nanocomposite ◽  
Bet Surface Area ◽  
Isotherm Models ◽  
Order Kinetic

In this work, magnetized activated Juniperus procera leaves (Fe3O4@AJPL) were successfully prepared via chemical activation of JPL and in situ coprecipitation with Fe3O4. A Fe3O4@AJPL nanocomposite was successfully applied for the elimination of malachite green (MG) dye from aqueous media. The prepared Fe3O4@AJPL adsorbent was characterized by SEM, EDX, TEM, XRD, FTIR, TGA, and BET surface area analyses. The BET surface area and pore size of the Fe3O4@AJPL nanocomposite were found to be 38.44 m2/g and 10.6 nm, respectively. The XRD and FTIR results indicated the formation of a Fe3O4@AJPL nanocomposite. Different parameters, such as pH of the solution (3–8), adsorbent dosage (10–100 mg), temperature (25–45°C), contact time (5-240 min), and initial MG concentrations (20–350 mg/L), for the elimination of the MG dye using Fe3O4@AJPL were optimized and found to be 7, 50 mg, 45°C, 120 min, and 150 mg/L, respectively. The nonlinear isotherm and kinetic studies exhibited a better fitting to second-order kinetic and Langmuir isotherm models, with a maximum monolayer adsorption capacity of 318.3 mg/g at 45°C, which was highly superior to the previously reported magnetic nanocomposite adsorbents. EDX analyses confirmed the presence of nitrogen on the Fe3O4@AJPL surface after MG adsorption. The calculated thermodynamic factors indicated endothermic and spontaneous processes. The desorption of MG dye from Fe3O4@AJPL was performed using a solution of 90% ethanol. Finally, it could be concluded that the designed Fe3O4@AJPL magnetic nanocomposite will be a cost-effective and promising adsorbent for the elimination of MG from aqueous media.

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