scholarly journals Adsorption of Para Substituted Anilines from Cyclohexane Solution on Sepiolite

1987 ◽  
Vol 4 (1-2) ◽  
pp. 79-85 ◽  
Author(s):  
E. Gonzalez-Pradas ◽  
A. Valverde-Garcia ◽  
M. Villaranca-Sanchez ◽  
F. Del ◽  
Rey Bueno
Keyword(s):  
Experimental Data ◽  
Adsorption Isotherms ◽  
Equilibrium Constants ◽  
Langmuir Equation ◽  
Substituted Anilines ◽  
Surface Areas ◽  
Adsorption Capacities ◽  
Adsorption Processes ◽  
Data Points ◽  
Apparent Equilibrium

The adsorption processes of different para-substituted anilines from cyclohexane solution on natural sepiolite have been studied. The adsorption isotherms may be classified as type L-2 of the Giles classification in the p-bromoaniline and p-toluidine cases, and as type H-2 in the p-acetylaniline case. The experimental data points have been fitted to the Langmuir equation and the adsorption capacities, surface areas available to the amine molecules and apparent equilibrium constants have been calculated. The apparent thermodynamic magnitudes corresponding to the adsorption processes have also been determined.

scholarly journals Removal of trace arsenic to below drinking water standards using a Mn–Fe binary oxide

RSC Advances ◽  
2017 ◽  
Vol 7 (3) ◽  
pp. 1490-1497 ◽  
Author(s):  
Jiefei Li ◽  
Hiroki Gyoten ◽  
Akinari Sonoda ◽  
Qi Feng ◽  
Mei Xue
Keyword(s):  
Drinking Water ◽  
Adsorption Isotherms ◽  
Langmuir Equation ◽  
Binary Oxide ◽  
Drinking Water Standards ◽  
Adsorption Capacities

The adsorption isotherms for As(iii) and As(v) followed the Langmuir equation, the saturation adsorption capacities (qm) by MF4/6-12 were evaluated as 50 mg g−1for both As(iii) and As(v).

Absorption Behavior of Methanol Vapor on the Silica Gels

2020 ◽  
Vol 1003 ◽  
pp. 156-162
Author(s):  
Ke Le Yan ◽  
Yu Lin ◽  
Wang Qian
Keyword(s):  
Experimental Data ◽  
Adsorption Equilibrium ◽  
Langmuir Equation ◽  
Silica Gels ◽  
Equilibrium Equations ◽  
Methanol Vapor ◽  
Freundlich Equation ◽  
Adsorption Capacities ◽  
Adsorption Data ◽  
The Rich

The adsorption behavior of methanol vapor onto three commercial silica gels named SG-1, SG-2 and SG-3 were investigated in this paper. The experimental results showed that SG-1 has the rich microporous, and the larger surface area and microporous volume than SG-2 and SG-3. The equilibrium adsorption data showed that the adsorption capacities of SG-1 was superior to SG-2 and SG-3 for lower concentration of methanol (<150 g/m3). However, SG-2 had higher adsorption capacities than SG-1 and SG-3 for higher concentration of methanol resulting from the condensation in mesopore channels. Three kinds of adsorption equilibrium equations including Langmuir equation, Freundlich equation and Dubinin-Astakov (D-A) equation were used to fit the methanol vapor adsorption isotherms. The results indicated that the experimental data can be well-fitted by D-A equation.

Identifying Physico-Chemical Laws from the Robotically Collected Data

2019 ◽  
Author(s):  
Liwei Cao ◽  
Danilo Russo ◽  
Vassilios S. Vassiliadis ◽  
Alexei Lapkin
Keyword(s):  
Experimental Data ◽  
Numerical Models ◽  
Predictor Variable ◽  
Physical Models ◽  
Training Data ◽  
Mixed Integer ◽  
Physico Chemical ◽  
Data Points ◽  
Future Work ◽  
The Relationship

<p>A mixed-integer nonlinear programming (MINLP) formulation for symbolic regression was proposed to identify physical models from noisy experimental data. The formulation was tested using numerical models and was found to be more efficient than the previous literature example with respect to the number of predictor variables and training data points. The globally optimal search was extended to identify physical models and to cope with noise in the experimental data predictor variable. The methodology was coupled with the collection of experimental data in an automated fashion, and was proven to be successful in identifying the correct physical models describing the relationship between the shear stress and shear rate for both Newtonian and non-Newtonian fluids, and simple kinetic laws of reactions. Future work will focus on addressing the limitations of the formulation presented in this work, by extending it to be able to address larger complex physical models.</p><p><br></p>

Comparative study of isotherm parameters of lead biosorption by two wastes of olive-oil production

2015 ◽  
Vol 72 (5) ◽  
pp. 711-720 ◽  
Author(s):  
G. Blázquez ◽  
A. Ronda ◽  
M. A. Martín-Lara ◽  
A. Pérez ◽  
M. Calero
Keyword(s):  
Experimental Data ◽  
Olive Tree ◽  
Langmuir Equation ◽  
Equilibrium Isotherm ◽  
Chemical Treatments ◽  
Olive Stone ◽  
Loss Of Mass ◽  
Best Fit ◽  
Tree Pruning ◽  
Effectiveness Coefficient

Batch isotherm studies were carried out on a laboratory scale: (i) to investigate the effectiveness to remove lead of two wastes (olive stone (OS) and olive tree pruning (OTP)), untreated and chemically treated; and (ii) to examine the applicability of various adsorption isotherms to fit the experimental data. Results from tests were analyzed using seven equilibrium isotherm correlations (Langmuir, Freundlich, Dubinin–Radushkevich, Temkin, Redlich–Peterson, Sips, and Toth equations). The sum of the squares of the errors was determined for each isotherm and the Langmuir equation provided the best fit. Chemical treatments increased the biosorption properties of these materials. The maximum biosorption capacities were: 6.33, 49.13, 14.83, and 38.93 mg g−1 for untreated OS, HNO3-OS, H2SO4-OS, and NaOH-OS, respectively, and 26.72, 86.40, 72.78, and 123.80 mg g−1 for untreated OTP, HNO3-OTP, H2SO4-OTP, and NaOH-OTP, respectively. Finally, the loss of mass for each waste (13.9, 14.3, and 36.8% for HNO3-OS, H2SO4-OS, and NaOH-OS and 35.1, 27.5, and 46.7% for HNO3-OTP, H2SO4-OTP, and NaOH-OTP, respectively) was taken into account and an effectiveness coefficient was determined for each adsorbent material.

Organic-free large-pore-sized γ-alumina for the removal of three azo dyes from aqueous solution

2021 ◽  
Vol 11 (9) ◽  
pp. 1534-1545
Author(s):  
Xuhui Wang ◽  
Jianchuan Sun ◽  
Shuaiqi Chen ◽  
Shuai Ren ◽  
Awang Gao ◽  
...  
Keyword(s):  
Dye Adsorption ◽  
Specific Area ◽  
Kinetics Study ◽  
Order Model ◽  
Surface Areas ◽  
Adsorption Capacities ◽  
Direct Blue ◽  
Calculation Results ◽  
Specific Surface Areas ◽  
Adsorption Rates

A series of γ-alumina with different pore sizes (5.7 nm–21.6 nm) and similar specific surface areas were synthesized via an organic-free method and their adsorption rates and capacities for Congo red (CR), direct blue 78 (DB78) and direct green 26 (DG26) were investigated. The kinetics study reveals that the dye adsorptions of all γ-alumina samples fit the pseudo-2nd-order model. For CR, its k2 and the pore size of absorbent are in a linear relationship at low dye concentrations. Both of the experimental results and Langmuir isotherm calculation results suggest that the dye adsorption capacities of the γ-alumina prepared in our lab are much higher than those of other γ-alumina reported in literatures. GA-1 with the largest specific area of surface and largest size of pores exhibits a CR adsorption capacity up to 4213.6 mg/g. In addition, initial dye adsorption rates of the γ-alumina prepared in-house are much higher than that of the γ-alumina prepared with the commercially available alumina under the same conditions.

scholarly journals Equilibrium Modeling of Astaxanthin Extraction from Haematococcus pluvialis

2021 ◽  
Vol 21 (3) ◽  
pp. 554
Author(s):  
Putri Restu Dewati ◽  
Rochmadi Rochmadi ◽  
Abdul Rohman ◽  
Avido Yuliestyan ◽  
Arief Budiman
Keyword(s):  
Experimental Data ◽  
High Performance ◽  
Haematococcus Pluvialis ◽  
Equilibrium Constants ◽  
Extraction Methods ◽  
Single Step ◽  
Equilibrium Models ◽  
Extraction Equilibrium ◽  
Assisted Extraction ◽  
Solid Liquid

Astaxanthin is a natural antioxidant, and the highest content of this compound is found in Haematococcus pluvialis microalgae. Microwave-assisted extraction (MAE) is one of the environmentally friendly extraction methods and has many advantages. This study aims to investigate the extraction of astaxanthin through the MAE method using various solvents. Several equilibrium models were proposed to describe this solid-liquid equilibrium. The solid-liquid extraction equilibrium parameters were determined by minimizing the sum of squares of errors (SSE), in which equilibrium constants were needed for scaling up purposes. Previously, the microalgae were pretreated with HCl to soften their cell walls in order to improve the extraction recovery. In this study, dichloromethane, acetone, methanol, and ethanol were used as the solvents for extraction. The astaxanthin concentration was determined by high-performance liquid chromatography (HPLC) and spectrophotometry. Astaxanthin was found to attain equilibrium at 57.42% recovery in a single-step extraction. Thus, several steps were required in sequence to obtain an optimum recovery. The experimental data were fitted to three equilibrium models, namely, Henry, Freundlich, and Langmuir models. The experimental data were well fitted to all the models for the extraction in dichloromethane, methanol, ethanol and acetone, as evident from the almost same SSE value for each model.

scholarly journals A Comparative Study of COD Removal Efficacy from Pharmaceutical Wastewater by Areca Nut Husk Produced and Commercially Available Activated Carbons

2021 ◽  
pp. 47-56
Author(s):  
Sharmin Akter ◽  
Ferdousi Sultana ◽  
Md. Rakibul Kabir ◽  
Partha Pratim Brahma ◽  
Atkeeya Tasneem ◽  
...  
Keyword(s):  
Experimental Data ◽  
Activated Carbon ◽  
Organic Contaminants ◽  
Activated Carbons ◽  
Low Cost ◽  
Oxygen Demand ◽  
Areca Nut ◽  
Pharmaceutical Wastewater ◽  
Adsorption Processes ◽  
Pharmaceutical Industries

Pharmaceutical industries in Bangladesh are considered as one major industrial as well as environmental pollution problems which discharge a significant amount of organic contaminants in the environment hence require advanced treatment technologies to decontaminate pharmaceutical wastewater. In the present investigation, areca nut husk treated activated carbon (ANHC) was used as an adsorbent to remove chemical oxygen demand (COD) from pharmaceutical effluent as well as a comparative adsorption efficiency with commercial activated carbon (CAC) was performed.  The batch experiments were carried out in a laboratory scale. The materials also evaluated for different adsorbent dosages and contact times. The experiment revealed a removal percentage up to 70% for ANHC and 90% for CAC for 3g of adsorbents in 180 min. The adsorption processes were satisfactorily described by pseudo-second-order (PSO) kinetic model which shows a better fitting with the maximum regression coefficient for both adsorbents. The results show that Langmuir model best described the experimental data with a highest correlation coefficient (R2=0.9856 for ANHC and 0.9993 for CAC) compared to Freundlich model and the experimental data showed asorption capacity of 36.549 and 64.935 mg/g for ANHC and CAC, correspondingly. According to the adsorption studies, the results revealed that COD adsorption process followed by the monolayer chemisorption mechanisms. The results revealed that ANHC adsorbent is potentially low cost and environmental friendly adsorbent for the removal of organic matter from pharmaceutical effluent.

scholarly journals Adsorption Equilibrium of 1, 1-Dichloro-1-fluoroethane (HCFC-141b) on a Hydrophobic Zeolite

1998 ◽  
Vol 16 (2) ◽  
pp. 67-75 ◽  
Author(s):  
Wen-Tien Tsai ◽  
Ching-Yuan Chang ◽  
Chih-Yin Ho
Keyword(s):  
Experimental Data ◽  
Free Energy ◽  
Thermodynamic Properties ◽  
Adsorption Isotherms ◽  
Ozone Depletion ◽  
Adsorption Equilibrium ◽  
Stratospheric Ozone ◽  
Stratospheric Ozone Depletion ◽  
Equilibrium Isotherms ◽  
Entropy Of Adsorption

Of the major replacements for chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) are now accepted as being prime contributors to stratospheric ozone depletion. As a consequence, the development of adsorbents capable of adsorbing and recovering specific HCFCs has received great attention. This paper describes an investigation of the adsorption equilibrium of 1, 1-dichloro-1-fluoroethane (HCFC-141b) vapour on a commercial hydrophobic zeolite. The corresponding Henry, Freundlich and Dubinin–Radushkevich (D–R) equilibrium isotherms have been determined and found to correlate well with the experimental data. Based on the Henry adsorption isotherms obtained at 283, 303 and 313 K. thermodynamic properties such as the enthalpy, free energy and entropy of adsorption have been computed for the adsorption of HCFC-141b vapour on the adsorbent. The results obtained could be useful in the application of HCFC adsorption on the hydrophobic zeolite studied.

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