The study of non-linear kinetics and adsorption isotherm models for Acid Red 18 from aqueous solutions by magnetite nanoparticles and magnetite nanoparticles modified by sodium alginate

2016 ◽  
Vol 74 (5) ◽  
pp. 1235-1242 ◽  
Author(s):  
Zohre Berizi ◽  
Seyed Yaser Hashemi ◽  
Mahdi Hadi ◽  
Ali Azari ◽  
Amir Hosein Mahvi
Keyword(s):  
Adsorption Isotherm ◽  
Sodium Alginate ◽  
Magnetite Nanoparticles ◽  
Linear Models ◽  
Freundlich Isotherm ◽  
Precipitation Method ◽  
Isotherm Models ◽  
Residual Concentration ◽  
Adsorption Isotherm Models ◽  
Non Linear

Azo dyes are widely used in various industries. These substances produce toxic byproducts in aquatic environments in addition to their mutagenic and carcinogenic potential effects. In this study, the effect of magnetite nanoparticles and magnetite nanoparticles modified by sodium alginate in batch systems and nonlinear kinetic and adsorption isotherm models were investigated. Magnetite nanoparticles were synthesized by chemical co-precipitation method and then modified and used as adsorbent to adsorb Acid Red 18. After determining the optimum pH and adsorbent dose, non-equilibrium models for kinetic adsorption were tested with concentrations (25–100 mg/L) and at eight different periods of time (1–15 min) and the pseudo-first-order and pseudo-second-order non-linear models were used to describe the results. For adsorption isotherm, a contact time of 120 min was studied in different concentrations (25–100 mg/L) and the residual concentration of Acid Red 18 was obtained. The results are described by non-linear Langmuir, Freundlich and Dubinin–Radushkevich isotherm models. The optimum amounts of pH for magnetite nanoparticles and for modified ones were 3 and 5, respectively, the efficiencies were 0.75 and 0.2 g/L, respectively. According to the results sodium alginate has a high performance in adsorption of Acid Red 18. Adjusted correlation coefficients and chi-square test showed that Freundlich isotherm and then Langmuir isotherm can well describe the experimental results. In Freundlich, the value of (Kf) was 3.231 (L/g) for magnetite nanoparticles and 21.615 (L/g) for modified adsorbent. In Langmuir, the value of (qm) was 16.259 (mg/g) for magnetite nanoparticles and 73.464 (mg/g) for modified adsorbent. Comparing the Langmuir maximum calculated adsorption capacity indicated that modified adsorbent can adsorb the pollutants 6.5 times more than the other one.

scholarly journals Comparative analysis of linear and nonlinear equilibrium models for the removal of metronidazole by tea waste activated carbon

2020 ◽  
Vol 82 (7) ◽  
pp. 1484-1494
Author(s):  
Peter Emmanuel Ebili ◽  
Manase Auta ◽  
Kehinde Shola Obayomi ◽  
Joseph Onyebuchi Okafor ◽  
Muibat Diekola Yahya ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Adsorption Isotherm ◽  
Active Sites ◽  
Linear Models ◽  
Physical Adsorption ◽  
Freundlich Isotherm ◽  
Cost Effective ◽  
Chi Square ◽  
Tea Waste ◽  
Non Linear

Abstract Tea waste was carbonized at 400 °C for 45 min and modified with potassium hydroxide (KOH), to enhance the active sites for the adsorption of antibiotics. The developed tea waste activated carbon (TWAC) was used as a novel eco-friendly and cost-effective adsorbent for metronidazole (MZN) removal from aqueous solution. The textural and surface properties of the adsorbent were determined using Brunauer-Emmett-Teller (BET) and FT-Raman analysis. The BET surface was found to have increased from 24.670 to 349.585 after carbonization and KOH modification. The batch experimental parameters were optimized and equilibrium time was found to be 75 min. Linear and non-linear models were carried out on the adsorption isotherm and kinetics to determine the best fit for the adsorption data. The adsorption equilibrium data were well fitted by the Freundlich isotherm and pseudo-second order models, with higher regression correlation (R2) and smaller chi-square (χ2), as predicted by the non-linear model. The thermodynamic results revealed the adsorption of MZN as spontaneous, physical, and consistently exothermic in character. The activation energy value of 7.610 kJ/mol further revealed that the adsorption process is dominated majorly by physical adsorption. The removal of MZN onto TWAC was best described by the non-linear adsorption isotherm and kinetics model.

scholarly journals Determination of Adsorption Isotherm Models for the Biosorption of Chromium Using Cherry Leaves (Muntingia calabura L.)

2014 ◽  
Vol 25 ◽  
pp. 12-17
Author(s):  
R. Aathithya ◽  
J. Rajani Sowparnika ◽  
V. Balakrishnan
Keyword(s):  
Heavy Metal ◽  
Adsorption Isotherm ◽  
Freundlich Isotherm ◽  
Isotherm Models ◽  
Major Threat ◽  
Chromium Vi ◽  
Adsorption Affinity ◽  
Adsorption Isotherm Models ◽  
Muntingia Calabura

Contaminations of industrial metals into the river possess major threat to environment. Chromium is a heavy metal which has the wide applications in tannery and electroplating industries. Above the permitted level of Chromium(VI) into surface water leads to severe health hazards. Therefore, biosorption is a technology used for the sorption of heavy metal. In this present study adsorption isotherm models was studied for the biosorption of chromium by cherry leaves. From the adsorption isotherms it was found that the experimental data fits well with the Langmuir isotherm than the Freundlich isotherm. The monolayer capacity Qm was fond to be 11.98 mg/l and the adsorption affinity was found to be positive which indicates the efficient biosorption of chromium

scholarly journals Adsorption of UV254 in Kerian River water onto ZeliacTM: Analysis using linear and non-linear forms of isotherm models

2017 ◽  
Vol 19 (1) ◽  
pp. 74-81 ◽  
Keyword(s):  
River Water ◽  
Function Analysis ◽  
Low Cost ◽  
Error Function ◽  
Linear Regression Analysis ◽  
Freundlich Isotherm ◽  
Linear Analysis ◽  
Isotherm Models ◽  
Freundlich Isotherms ◽  
Non Linear

<p>The composite media, Zeliac<sup>TM</sup> was developed with the initial aim to provide low cost adsorbent with promising adsorption capacity. This study was conducted to investigate the removal of UV absorbance at 254 nm (UV<sub>254</sub>) in Kerian river water using Zeliac<sup>TM</sup> as the media. Batch experiments study was carried out to determine the optimum removal of UV<sub>254</sub> by Zeliac<sup>TM</sup>. The experimental data were fitted to Langmuir and Freundlich isotherms to investigate the adsorption mechanism. The results from batch study exhibit that Zeliac<sup>TM</sup> is capable to remove 74.4% UV<sub>254</sub> at the dosage of 7g/100 ml. Linear isotherm analysis suggests that the best fitting linear line is Freundlich isotherm with R<sup>2</sup> values of 0.9294 indicating multilayer adsorption. Similarly, non-linear regression analysis reveals that the adsorption of UV<sub>254</sub> by Zeliac<sup>TM</sup> is attributed by physisorption. The non-linear Freundlich isotherm gives a better fit to the adsorption of UV<sub>254</sub> than Langmuir isotherm with R<sup>2</sup> values of 0.9488. The results are supported with low values of X<sup>2</sup>, ARE, HYBRID and MPSED from the error function analysis.&nbsp; Additionally, it is noted that the linear analysis overestimates the constant parameters’ values for Freundlich isotherm, which cause larger errors as estimated by the error function analysis. Hence, non-linear analysis is more appropriate in explaining the batch experiment data.</p>

scholarly journals Biosorption potentials of acid modified Saccharum bengalense for removal of methyl violet from aqueous solutions

2017 ◽  
Vol 23 (3) ◽  
pp. 399-409 ◽  
Author(s):  
Muhammad Din ◽  
Kiran Ijaz ◽  
Khalida Naseem
Keyword(s):  
Experimental Data ◽  
Adsorption Isotherm ◽  
Aqueous Medium ◽  
Methyl Violet ◽  
Isotherm Models ◽  
Langmuir Adsorption ◽  
First Order ◽  
Adsorption Isotherm Models ◽  
Intra Particle Diffusion ◽  
Pseudo Second Order

In the present work, Saccharum bengalense (SB) was treated with sulfuric acid to enhance its efficiency. Methyl violet (MV), a cationic dye, was removed from aqueous medium using acid modified S. bengalense (A-SB). Different parameters like adsorbent dosage, stirring speed, temperature, contact time and effect of initial concentration of dye on rate of adsorption of dye from aqueous medium was studied. Experimental data obtained from adsorption of MV was analyzed by applying pseudo first order, pseudo second order and intra-particle diffusion models and it was found that the data best follows the pseudosecond order kinetics. Thermodynamic parameters indicate that adsorption reaction was spontaneous, feasible and endothermic in nature. Different adsorption isotherm models, like Langmuir, Freundlich, Dubinin-Radushkevich (D-R) and Temkin, were used to study the mechanism of adsorption process and experimental data was well fitted by the Langmuir adsorption isotherm.

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