scholarly journals A Stochastic Model for Adsorption Kinetics

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Silvia Rodríguez-Narciso ◽  
Juan Antonio Lozano-Álvarez ◽  
Rogelio Salinas-Gutiérrez ◽  
Netzahualcóyotl Castañeda-Leyva
Keyword(s):  
Stochastic Model ◽  
Adsorption Kinetics ◽  
Pollutant Removal ◽  
Adsorption Parameters ◽  
Fluoride Ions ◽  
Removal Capacity ◽  
Direct Blue ◽  
Calcium Pectinate ◽  
Pseudo Second Order ◽  
Kinetics Of

A novel stochastic model is proposed to characterize the adsorption kinetics of pollutants including dyes (direct red 80 and direct blue 1), fluoride ions, and cadmium ions removed by calcium pectinate (Pec-Ca), aluminum xanthanate (Xant-Al), and reed leaves, respectively. The model is based on a transformation over time following the Ornstein–Uhlenbeck stochastic process, which explicitly includes the uncertainty involved in the adsorption process. The model includes stochastic versions of the pseudo-first-order (PFO), pseudo-second-order (PSO), and pseudo- n -order (PNO) models. It also allows the estimation of the adsorption parameters, including the maximum removal capacity ( q e ), the adsorption rate constant ( k n ), the reaction pseudoorder ( n ), and the variability σ 2 . The model fitted produced R 2 values similar to those of the nonstochastic versions of the PFO, PSO, and PNO models; however, the obtained values for each parameter indicate that the stochastic model better reproduces the experimental data. The q e values of the Pec-Ca-dye, Xant-Al-fluoride, and reed leaf-Cd+2 systems ranged from 2.0 to 9.7, 0.41 to 1.9, and 0.04 and 0.29 mg/g, respectively, whereas the values of k n ranged from 0.051 to 0.286, 0.743 to 75.73, and 0.756 to 8.861 (mg/g)1-n/min, respectively. These results suggest a variability in the parameters q e and k n inherent to the natures of the adsorbate and adsorbent. The obtained n values ranged from 1.13 to 2.02 for the Pec-Ca-dye system, 1.0–3.5 for the Xant-Al-fluoride system, and 1.8–3.8 for the reed leaf-Cd+2 system. These ranges indicate the flexibility of the stochastic model to obtain fractional n values, resulting in high R 2 values. The variability in each system was evaluated based on σ 2 . The developed model is the first to describe pollutant removal kinetics based on a stochastic differential equation.

Study on the Formaldehyde Adsorption Kinetics of Dry Waters

2014 ◽  
Vol 809-810 ◽  
pp. 907-911
Author(s):  
Jun Long Wang ◽  
Jie Hou ◽  
Ting Jiang ◽  
Yong Jun He ◽  
Yao Dong Liang
Keyword(s):  
Adsorption Kinetics ◽  
High Speed ◽  
Adsorption Process ◽  
Average Diameter ◽  
Adsorption Rate ◽  
Absorption Kinetics ◽  
Order Model ◽  
Pseudo Second Order ◽  
Kinetics Of ◽  
Formaldehyde Adsorption

Dry waters with an average diameter of 82 μm were prepared by a high speed mixed route. The formaldehyde absorption kinetics of dry waters was investigated by simulating indoor formaldehyde pollution in glass chamber. The results showed that pseudo-second order model could be used to simulate the adsorption process; the adsorption rate was highest in the initial 60 minutes; when the adsorption lasted for 180 minutes, the adsorption reached equilibrium.

Adsorption Kinetics of Pb2+ Ions Using Chitosan Nanoparticles

2013 ◽  
Vol 367 ◽  
pp. 45-49
Author(s):  
Ying Hong ◽  
Ze Hui Zhong ◽  
You Shi Liu
Keyword(s):  
Adsorption Kinetics ◽  
Chitosan Nanoparticles ◽  
Second Order ◽  
Isotherm Model ◽  
Order Model ◽  
Adsorption Characteristics ◽  
Pseudo Second Order ◽  
Kinetics Of ◽  
Second Order Model

Chitosan nanoparticles were prepared by crosslinkingusing TPP. SEM showed that chitosan nanoparticles were successfully obtained.The adsorption characteristics of chitosan nanoparticles were evaluated. Theresults demonstrated that chitosan nanoparticles were suitable for adsorbent toremoval Pb2+. The parameters for the adsorption of Pb2+by chitosan nanoparticles were also determined. It was shown that chitosannanoparticles were fit for Langmuir’s isotherm model and that the adsorptionkinetics of Pb2+ described by the pseudo-second-order model could bebest.

Kinetic and equilibrium studies of fluoride sorption onto surfactant-modified smectites

Clay Minerals ◽  
2012 ◽  
Vol 47 (4) ◽  
pp. 429-440 ◽  
Author(s):  
S. Gamoudi ◽  
N. Frini-Srasra ◽  
E. Srasra
Keyword(s):  
Aqueous Solution ◽  
Thermodynamic Parameters ◽  
Adsorption Kinetics ◽  
Equilibrium Constants ◽  
Second Order ◽  
Operating Conditions ◽  
Polluted Water ◽  
Isotherm Models ◽  
Fluoride Ions ◽  
Pseudo Second Order

AbstractThe use of organoclays as adsorbents in the remediation of polluted water has been the subject of many recent studies. In the present work, a Tunisian smectite modified with two cationic surfactants was used as an adsorbent to examine the adsorption kinetics, isotherms and thermodynamic parameters of fluoride ions from aqueous solution. Various pH values, initial concentrations and temperatures have been tested. Two simplified kinetic models, first-order and pseudo-second-order, were used to predict the adsorption rate constants. It was found that the adsorption kinetics of fluoride onto modified smectites at different operating conditions can best be described by the pseudo-second-order model. Adsorption isotherms and equilibrium adsorption capacities were determined by the fitting of the experimental data to well known isotherm models including those of Langmuir and Freundlich. The results showed that the Langmuir model appears to fit the adsorption better than the Freundlich adsorption model for the adsorption of fluoride ions onto modified smectites. The equilibrium constants were used to calculate thermodynamic parameters, such as the change of free energy, enthalpy and entropy. Results of this study demonstrated the effectiveness and feasibility of organoclays for the removal of fluoride ions from aqueous solution.

scholarly journals Removal Effect of Atrazine in Co-Solution with Bisphenol A or Humic Acid by Different Activated Carbons

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2558 ◽  
Author(s):  
Zhansheng Wu ◽  
Xinhui Wei ◽  
Yongtao Xue ◽  
Xiufang He ◽  
Xia Yang
Keyword(s):  
Humic Acid ◽  
Bisphenol A ◽  
Adsorption Kinetics ◽  
Competitive Adsorption ◽  
Activated Carbons ◽  
Second Order ◽  
Adsorption Behavior ◽  
Single Solution ◽  
Pseudo Second Order ◽  
Kinetics Of

Activated carbons (ACs) based on apricot shells (AS), wood (W), and walnut shells (WS) were applied to adsorb atrazine in co-solutions. To study the effect of Bisphenol A (BPA) on the adsorption behavior of atrazine, the adsorption performance of ACs for BPA in single solution was studied. The results demonstrated that the adsorption kinetics of BPA fitted the pseudo-second-order model, the adsorption isotherms of BPA followed the Langmuir model. Meanwhile, the adsorption kinetics of atrazine fitted the pseudo-second-order kinetics model and the isotherm was consistent with the Freundlich model both in single solution and co-solution. In addition, competitive adsorption was observed when atrazine coexisted with BPA or humic acid. For the adsorption capacity, the adsorption amount of ASAC, WAC, and WSAC for atrazine obviously decreased by 18.0%, 30.0%, and 30.3% in the presence of BPA, respectively, which was due to the π−π interactions, hydrophobic interactions, and H-bonds, resulting in the competitive adsorption between atrazine and BPA. This study contributes to the further understanding of the adsorption behavior for atrazine in co-solution.

Adsorption Kinetics of Zn(II) from Aqueous Solutions onto Epichlorohydrin Crosslinked Chitosan

2012 ◽  
Vol 463-464 ◽  
pp. 7-11 ◽  
Author(s):  
Ming Yan Dang ◽  
Hong Min Guo ◽  
Yan Kun Tan
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Kinetics ◽  
Ph Value ◽  
Crosslinking Agent ◽  
Second Order ◽  
Order Model ◽  
Pseudo Second Order ◽  
Crosslinked Chitosan ◽  
Kinetics Of ◽  
Second Order Model

Chitosan was crosslinked using epichlorohydrin as crosslinking agent to prepare crosslinked chitosan which was used as an adsorbent for the removal of Zn(II) from aqueous solutions. The adsorption prosperities of Zn(II) on crosslinked chitosan were studied, including the influence of pH value and the adsorption kinetics. The kinetics of adsorption was discussed using two kinetic models, the pseudo first-order and the pseudo second-order model. Results reveal that the crosslinked chitosan is suitable as adsorbent to remove Zn(II) from dilute solution. The rate parameters for the Zn(II) by crosslinked chitosan were also determined. It was shown that the adsorption kinetics of Zn(II) could be best described by the pseudo second-order model and the adsorption process may involve a physical adsorption.

Adsorption kinetics of Remazol Brilliant Blue R dye from liquid effluents by bovine bone charcoal

2020 ◽  
Vol 1 (1) ◽  
pp. 11717
Author(s):  
Lívia Katia Dos Santos Lima ◽  
Antônio Vilas Boas Quintiliano Júnior ◽  
André Henrique Zeferino ◽  
Ana Paula Duarte
Keyword(s):  
Activated Carbon ◽  
Adsorption Kinetics ◽  
Intraparticle Diffusion ◽  
Brilliant Blue ◽  
Bovine Bone ◽  
First Order ◽  
Remazol Brilliant Blue R ◽  
Pseudo Second Order ◽  
Pseudo First Order ◽  
Kinetics Of

The textile industry stands out for generating effluents with high levels of dyes, which have a high polluting potential. Among these dyes, the Remazol Brilliant Blue R azo dye, is one of the most used for dyeing wool and cotton, being released in excess on these effluents. Intended for the carcinogenic and mutagenic potential of this type of dyes, several researches are developed in search of economical technologies for their removal. An adsorption is a viable technique, since several materials can be used for this purpose. Bovine bone activated carbon, as it is a residue from the livestock industry that is easily obtained, has been studied as an adsorbent material in the removal of dyes. Therefore, the objective of this project was to evaluate the performance of the adsorption kinetics of the Remazol Brilliant Blue R dye from the effluents using bovine bone activated carbon. The experiments were carried out in batches, with solutions concentrations of 20, 50 and 100 ppm, and the mathematical models of pseudo-first order, pseudo-second order and intraparticle diffusion were adjusted to the experimental data. For concentrations of 20 and 50 ppm, the model that best fits was the pseudo-first order, while for the concentration of 100 ppm the pseudo-second order model obtained the best result with R2 of 0.992. The intraparticle diffusion model showed that the higher the concentration of the dye in solution, the greater the thickness of the boundary layer and that the intraparticle diffusion does not control the adsorption process in any of the study criteria.

Adorption and Kinetics Studies of Baritite on Cr (VI) from Aqueous Solutions

2011 ◽  
Vol 347-353 ◽  
pp. 281-284
Author(s):  
Peng Ge ◽  
Li Juan Wan ◽  
Ya Jing Xu
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Adsorption Kinetics ◽  
Natural Zeolite ◽  
Second Order ◽  
Order Model ◽  
Kinetics Studies ◽  
Pseudo Second Order ◽  
Kinetics Of

Among the investigated clays and minerals (kaolinite, natural zeolite, manual zeolite, bentonite, sepiolite, sepiolite amianthus, tremolite amianthus, vermiculite and baritite), the baritite clay was selected as the optimal adsorbent for aqueous Cr (VI). The Cr (VI) adsorption capacity on baritite clay reached as high as 39.01 mg∙g−1 at 20°C. Then the adsorption kinetics of Cr (VI) by the baritite clay were investigated in details. Results showed that the pseudo-second-order model was a suitable description for the adsorption kinetics and fitted well with the experimental data.

Fabrication and Methyl Blue Adsorption Kinetics of α-Fe2O3 Nanotubes by Electrospinning

2013 ◽  
Vol 699 ◽  
pp. 302-307
Author(s):  
Qiu Ju Wang ◽  
Rui Jiang Liu ◽  
Xiang Qian Shen ◽  
Ding Mei Wu ◽  
He Hao Li
Keyword(s):  
Adsorption Kinetics ◽  
Average Diameter ◽  
Methyl Blue ◽  
Order Kinetic ◽  
Calcination Process ◽  
Hematite Phase ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Xrd Patterns ◽  
Kinetics Of

The α-Fe2O3nanotubes were prepared by the eletrospinning and calcination process. The as-prepared α-Fe2O3nanotubes were characterized by XRD, SEM and BET. The XRD patterns show that the nanotubes with a pure hematite phase (α-Fe2O3) are obtained after calcination at 550 oC. The SEM morphologies and BET measurement demonstrate the nanotubes have an average diameter of 200-300 nm and a specific surface area of 15.1 m2/g. Their adsorption of methyl blue was studied with ultraviolet spectrophotometer (UV) to measure the concentration of methyl blue in aqueous solution, and the adsorption kinetics is basically in agreement with the pseudo-second-order kinetic model in the methyl blue concentration range of 100-300 mg/L.

Adsorption Kinetics of Nickel Etioporphyrin on VTB-Asphaltene in N-Pentane Solution

2013 ◽  
Vol 781-784 ◽  
pp. 24-29
Author(s):  
Fei Fei Chen ◽  
Zhi Ming Xu ◽  
Xue Wen Sun ◽  
Suo Qi Zhao
Keyword(s):  
Adsorption Kinetics ◽  
Oil Sands ◽  
Removal Rate ◽  
Adsorption Rate ◽  
Low Molecular Weight ◽  
Pseudo Second Order ◽  
Alkane Solvents ◽  
Solvent Deasphalting ◽  
Oil Sands Bitumen ◽  
Kinetics Of

It is important to find out how to strengthen the interaction between nickel porphyrins and asphaltene in the alkane solvents of the low molecular weight for raising the removal rate of nickel in the solvent deasphalting process. Therefore, the adsorption kinetics, which describes how the nickel etioporphyrins are adsorbed on asphaltene (the vacuum residue of Canadian oil sands bitumen (VTB)) in the n-pentane solvent, are investigated. The results show that a certain amount of nickel porphyrins is absorbed on the asphaltene of VTB, which means there is a certain adsorption between asphaltene and nickel porphyrins. The adsorption rate is affected by the dosage of asphaltene, the concentration of the n-pentane solution containing nickel porphyrins and the temperature. A comparison in the four kinds of kinetic models on the overall adsorption rate shows that adsorption process can be perfectly described by the pseudo second-order equation.

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