scholarly journals Isotherm, Kinetics and Thermodynamic Studies of Hexavalent Chromium Adsorption by Using Dead Biomass of Eichhornia crassipes

2020 ◽  
Vol 36 (05) ◽  
pp. 915-922
Author(s):  
Sunil Kumar ◽  
Rajesh Dhankhar
Keyword(s):  
Hexavalent Chromium ◽  
Eichhornia Crassipes ◽  
Freundlich Isotherm ◽  
Particle Diffusion ◽  
Dead Biomass ◽  
Intra Particle Diffusion ◽  
Pseudo Second Order ◽  
Chromium Adsorption ◽  
Kinetics And Thermodynamic

This study examined the utilization of Raw Eichhornia crassipes (REC) biomass to exclude the hexavalent chromium heavy metal from synthetic liquid for determination of sorption isotherm, kinetics and thermodynamic parameters of adsorption during the batch experiment process. The effect of adsorbent doses, agitation time and temperature on sorption capacity was studied. The plot qt versus t1/2 determined the intra-particle diffusion effect, which was not passing from the origin of plot indicated that apart from intra-particle diffusion some other mechanism also involved in this study. Freundlich isotherm better fitted as compared to Langmuir isotherm in the present study. The kinetics study show that pseudo-second-order better followed by REC adsorbent. At 293 K temperature, Δ Go negative value suggested that process favoured the sorption and spontaneous in nature, but at higher temperatures, positive values Δ Go confirmed the non-spontaneous nature of adsorption. It is concluded that Eichhornia crassipes dead biomass has the potential to treat wastewaters as an adsorbent.

scholarly journals Guidelines for general adsorption kinetics modeling

2020 ◽  
Vol 74 (1) ◽  
pp. 65-70
Author(s):  
Bojana Obradovic
Keyword(s):  
Adsorption Kinetics ◽  
Scale Up ◽  
Second Order ◽  
Particle Diffusion ◽  
Analysis And Evaluation ◽  
Inappropriate Use ◽  
Adsorption Processes ◽  
Intra Particle Diffusion ◽  
Elovich Equation ◽  
Pseudo Second Order

Adsorption processes are widely used in different technological areas and industry sectors, thus continuously attracting attention in the scientific research and publications. Design and scale-up of these processes are essentially based on the knowledge and understanding of the adsorption kinetics and mechanism. Adsorption kinetics is usually modeled by using several well-known models including the pseudo-first and pseudo-second order models, the Elovich equation, and the intra-particle diffusion based models. However, in the scientific literature there are a significant number of cases with the inappropriate use of these models, utilization of erroneous expressions, and incorrect interpretation of the obtained results. This paper is especially focused on applications of the pseudo-second order, intra-particle diffusion and the Weber-Morris models, which are illustrated with typical examples. Finally, general recommendations for selection of the appropriate kinetic model and model assumptions, data regression analysis, and evaluation and presentation of the obtained results are outlined.

Removal of fluoride from aqueous solution by adsorption onto Kanuma mud

2010 ◽  
Vol 62 (8) ◽  
pp. 1888-1897 ◽  
Author(s):  
Nan Chen ◽  
Zhenya Zhang ◽  
Chuanping Feng ◽  
Miao Li ◽  
Rongzhi Chen ◽  
...  
Keyword(s):  
Adsorption Process ◽  
Fluoride Concentration ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
Solution Ph ◽  
Intra Particle Diffusion ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Solid Liquid Interface ◽  
Solid Liquid

Kanuma mud, a geomaterial, is used as an adsorbent for the removal of fluoride from water. The influences of contact time, solution pH, adsorbent dosage, initial fluoride concentration and co-existing ions were investigated by batch equilibration studies. The rate of adsorption was rapid with equilibrium being attained after about 2 h, and the maximum removal of fluoride was obtained at pH 5.0–8.0. The Freundlich isotherm model was found to represent the measured adsorption data well. The negative value of the thermodynamic parameter ΔG suggests the adsorption of fluoride by Kanuma mud was spontaneous, the endothermic nature of adsorption was confirmed by the positive ΔH value. The negative ΔS value for adsorbent denoted decreased randomness at the solid/liquid interface. The adsorption process using Kanuma mud followed the pseudo-second-order kinetic model. Fluoride uptake by the Kanuma mud was a complex process and intra-particle diffusion played a major role in the adsorption process. It was found that adsorbed fluoride could be easily desorbed by washing the adsorbent with a solution of pH 12. This indicates the material could be easily recycled.

Application of the intra-particle diffusion model for activated carbon fibers in an aqueous medium

2012 ◽  
Vol 1373 ◽  
Author(s):  
Teresa Ramírez-Rodríguez ◽  
Fray de Landa Castillo-Alvarado
Keyword(s):  
Activated Carbon ◽  
Diffusion Model ◽  
Carbon Fibers ◽  
Aqueous Media ◽  
Particle Diffusion ◽  
Activated Carbon Fibers ◽  
Kinetics Of Adsorption ◽  
Intra Particle Diffusion ◽  
Pseudo Second Order ◽  
Kinetics Of

ABSTRACTThe intra-particle diffusion model (IPD), proposed by Weber and Morris has been applied to the analysis of the kinetics of adsorption on activated carbon fibers with phosphate groups in the removal of cadmium ions in aqueous media. It is evident that the removal of cadmium ion kinetic model of pseudo-second order provides a better fit than the model of pseudo-first order and the intra-particle diffusion model provides the best to the sample compared activating solution: grams fibers of 1:3.

scholarly journals Development of Cerium Oxide/Corncob Nanocomposite: A Cost-Effective and Eco-Friendly Adsorbent for the Removal of Heavy Metals

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4464
Author(s):  
Sidra Gran ◽  
Rukhsanda Aziz ◽  
Muhammad Tariq Rafiq ◽  
Maryam Abbasi ◽  
Abdul Qayyum ◽  
...  
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Contact Time ◽  
Cost Effective ◽  
Particle Diffusion ◽  
Order Kinetic ◽  
Removal Of Heavy Metals ◽  
Intra Particle Diffusion ◽  
Order Kinetic Model ◽  
Pseudo Second Order

This research aims to assess the efficiency of the synthesized corncob as a cost-effective and eco-friendly adsorbent for the removal of heavy metals. Therefore, to carry out the intended research project, initially, the corncob was doped with nanoparticles to increase its efficiency or adsorption capacity. The prepared adsorbent was evaluated for the adsorption of cadmium (Cd) and chromium (Cr) from aqueous media with the batch experiment method. Factors that affect the adsorption process are pH, initial concentration, contact time and adsorbent dose. The analysis of Cd and Cr was performed by using atomic absorption spectrometry (AAS), while the characterization of the adsorbent was performed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results showed that there is a significant difference before and after corncob activation and doping with CeO2 nanoparticles. The maximum removal for both Cd and Cr was at a basic pH with a contact time of 60 min at 120 rpm, which is 95% for Cd and 88% for Cr, respectively. To analyze the experimental data, a pseudo-first-order kinetic model, pseudo-second-order kinetic model, and intra-particle diffusion model were used. The kinetic adsorption studies confirmed that the experimental data were best fitted with the pseudo-second-order kinetic model (R2 = 0.989) and intra-particle diffusion model (R2 = 0.979). This work demonstrates that the cerium oxide/corncob nanocomposite is an inexpensive and environmentally friendly adsorbent for the removal of Cd and Cr from wastewater.

scholarly journals Adsorption of Crystal Violet Dye onto Tamarind Seed Powder

2010 ◽  
Vol 7 (3) ◽  
pp. 975-984 ◽  
Author(s):  
Himanshu Patel ◽  
R. T. Vashi
Keyword(s):  
Crystal Violet ◽  
Adsorption Mechanism ◽  
Freundlich Isotherm ◽  
Tamarind Seed ◽  
Crystal Violet Dye ◽  
Adsorption Data ◽  
Equilibrium Data ◽  
Intra Particle Diffusion ◽  
Pseudo Second Order ◽  
Shell Powder

The present investigation describes adsorption of crystal violet dye from its aqueous solution onto tamarind (Tamarindus indica) fruit shell powder. Initial concentration, agitation speed and pH with various temperature have been studied, in which pH was found to be most effective. The adsorption data were mathematically analyzed using adsorption isotherm like Freundlich and Langmuir isotherm to study adsorption mechanism of crystal violet onto this seed powder. Freundlich isotherm was found to be most applicable. The equilibrium data were applied to intra-particle diffusion and adsorption kinetics. The reaction was found to be pseudo second order.

Kinetics and Thermodynamics of Adsorption of Cr(VI) on Nano Magnetic NiFe Particles in an Aqueous Solution

2015 ◽  
Vol 1120-1121 ◽  
pp. 286-290
Author(s):  
Lin Zhang ◽  
Kai Ge liu ◽  
Zhao Wen Zhang ◽  
Yan Liu
Keyword(s):  
Aqueous Solution ◽  
Mass Transfer ◽  
Freundlich Isotherm ◽  
Particle Diffusion ◽  
Order Kinetic ◽  
Nano Materials ◽  
Pseudo Second Order ◽  
Internal Particle ◽  
Diffusion Mass ◽  
Adsorption Quantity

Magnetic nano materials were known as high adsorption properties Nano-structural Ni2.33Fe alloy was successfully prepared by hydrothermal method and was used to remove CrO42- ions from aqueous solution. The results show that the equilibrium adsorption quantity increased with the increase of initial CrO42- concentration and pseudo-second-order kinetic models were successfully used for fitting the kinetic data. Webb Maurice diffusion model shows adsorption was controlled by external mass transfer followed by internal particle diffusion mass transfer. And the fitting degree of the Langmuir isotherm and the experimental data was quite high. And the Freundlich isotherm also fitted well.

scholarly journals The Biosorption Features of Cr (VI) Ions by Dried Biomass of a Facultative Anaerobic Bacillus cereus Strain Pf-1

2019 ◽  
pp. 1-14
Author(s):  
Paul Fabrice Nguema ◽  
Zejiao Luo ◽  
Zachari Mohamadou Mounir ◽  
Lian Jing Jing
Keyword(s):  
Bacillus Cereus ◽  
Particle Diffusion ◽  
Order Kinetic ◽  
Biosorption Process ◽  
Rate Determining Step ◽  
Biosorption Mechanism ◽  
Intra Particle Diffusion ◽  
Pseudo Second Order ◽  
Ionic Nature ◽  
Langmuir And Freundlich Models

Many studies were undertaken on the biosorption potential of different kinds of biomaterials. However, there is a paucity of data regarding the biosorption mechanism of Cr (VI) using dried cells. In our study, the removal of Cr (VI) from aqueous solution was investigated in a batch system by the dried biomass of a chromium-resistant bacterium isolated from activated sludge samples. Equilibrium and kinetic experiments were undertaken at various initial metal concentration, pH, and biosorbent dosage. Bacillus cereus biomass was characterized using Energy-Dispersive X-ray (EDX), Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). Biosorption process was found to be pH dependent. The optimum pH was found to be 2.0. The Langmuir and Freundlich were considered to identify the isotherm that could better describe the equilibrium adsorption of Cr (VI) onto the biomass. Langmuir and Freundlich models fitted our experimental data. The suitability of the pseudo-first order and pseudo-second order kinetic models for the biosorption of Cr (VI) onto Bacillus cereus was also performed. The mechanism for the adsorption was studied by fitting the kinetic data with the Boyd plot and intra-particle diffusion model. External mass transfer was found to be the rate-determining step. Based on the ionic nature of the metal, the intra-particle diffusion and extent of film diffusion varied. 

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.

Scandium adsorption from sulfuric-chloride solutions with activated carbons

2019 ◽  
pp. 49-55
Author(s):  
Wai Moe Aung ◽  
M. V. Marchenko ◽  
I. D. Troshkina
Keyword(s):  
Correlation Coefficient ◽  
Diffusion Model ◽  
Activated Carbons ◽  
Second Order ◽  
Model Description ◽  
Particle Diffusion ◽  
Diffusion Region ◽  
Chloride Solutions ◽  
Intra Particle Diffusion ◽  
Pseudo Second Order

The study covers scandium adsorption in batch conditions by VSK, DAS and PFT activated carbon grades (Russia) of different origin (сoconut shell, аnthracite, thermoset waste, respectively) from sulfuric acid-chloride solutions (pH = 2) simulating the composition of the underground leaching solutions of polymetallic ores. It was found that scandium adsorption by DAS and VSK carbons proceeds with the highest distribution coefficients (133 and 45.8 cm3/g, respectively). Isotherms of scandium adsorption with these carbons are linear and described by the Henry equation with constants 133 ± 21 and 46 ± 7 cm3/g, respectively. A limited solution volume method was used to obtain the integral kinetic curves of scandium adsorption. Their linearization according to the kinetic models of the pseudo-first, pseudo-second order, the Elovich model and the Weber–Morris intra-particle diffusion model indicates that the kinetics of scandium adsorption with VSK carbon having a higher correlation coefficient (0.999) is described using the pseudo-second order model. Description of the kinetic data obtained during the adsorption of scandium with DAS carbon showed that for all the models used the correlation coefficient is low (<0.939), while the highest value is observed when using the intra-particle diffusion model. It was suggested that the scandium adsorption process occurs in the mixed diffusion region. The possibility of scandium elution from VSK and DAS carbons with sodium carbonate solution (10 %) was studied in batch conditions, where the degree of scandium desorption in two stages of elution was 84.0 and 90.4 %, respectively.

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