scholarly journals Kinetic, isotherm and thermodynamic studies with linear and non-linear fitting for cadmium(II) removal by black carbon of pine cone

2017 ◽  
Vol 76 (8) ◽  
pp. 2242-2253 ◽  
Author(s):  
Z. Yavari ◽  
M. Noroozifar
Keyword(s):  
Aqueous Solutions ◽  
Black Carbon ◽  
Adsorption Process ◽  
Order Kinetic ◽  
Cadmium Removal ◽  
Thermodynamic Studies ◽  
Linear Fitting ◽  
Pine Cone ◽  
Fitting Method ◽  
Non Linear

In this study, black carbon from pine cone (BCPC) and acidic-modified BCPC (MBCPC) powder as a popular agricultural waste in the southeast of Iran were used for cadmium removal from aqueous solutions. The effect of various factors, such as surface chemistry and dosage of adsorbent, contact time, size of particles, initial concentration of cadmium, temperature, and pH of aqueous solutions, was investigated. The results show cadmium removal with usage of the mentioned adsorbents increased after acidic modification. It was noteworthy in this work that the removal percentage of pollutant was above 90% for suggested biosorbents. The obtained experimental data for optimum conditions were selected to model the adsorption behavior of the materials with usage of six isotherm equations via non-linear fitting method and the residual root mean square error estimation for each model. The adsorption of cadmium preferably fitted Khan and Langmuir–Freundlich isotherms for BCPC and MBCPC adsorbents, respectively. The kinetic studies via linear fitting method proved the second-order kinetic was the applicable model for the adsorption process. Thermodynamic studies show the adsorption process of cadmium onto BCPC and MBCPC was spontaneous and endothermic.

The non-linear fitting method to analyze the measured M–S plots of bipolar passive films

2010 ◽  
Vol 55 (7) ◽  
pp. 2498-2504 ◽  
Author(s):  
Ruijing Jiang ◽  
Changfeng Chen ◽  
Shuqi Zheng
Keyword(s):  
Passive Films ◽  
Linear Fitting ◽  
Fitting Method ◽  
Non Linear

Experimental Analysis of the Wind Farm and Numerical Site Calibration

2007 ◽  
Author(s):  
T. Kamio ◽  
M. Iida ◽  
C. Arakawa
Keyword(s):  
Weibull Distribution ◽  
Complex Terrain ◽  
Wind Farm ◽  
Wind Data ◽  
Estimation Methods ◽  
Linear Fitting ◽  
Fitting Method ◽  
Non Linear ◽  
Wind Characteristics ◽  
The Difference

This paper mentions the difference of estimation methods for the Weibull distribution using the wind data that were measured at more than 300 locations to clarify the wind characteristics in a complex terrain. As the result, the Weibull distribution function is approximated the experimental wind data by the non-linear fitting method rather than the linear fitting method. Then the numerical site calibration with MASCOT which is the non-linear numerical wind prediction model and WaSP are run out on a complex terrain in Japan.

scholarly journals Lead and cadmium removal by adsorption process using hydroxyapatite porous materials

2020 ◽  
Vol 15 (1) ◽  
pp. 130-141 ◽  
Author(s):  
Amina Ramdani ◽  
Abdelkader Kadeche ◽  
Mehdi Adjdir ◽  
Zoubida Taleb ◽  
Djamila Ikhou ◽  
...  
Keyword(s):  
Porous Materials ◽  
Adsorption Process ◽  
Industrial Effluents ◽  
Order Kinetic ◽  
Cadmium Removal ◽  
Lead And Cadmium ◽  
Isotherm Adsorption ◽  
Order Kinetic Model ◽  
Removal Efficiencies ◽  
Time Required

Abstract This contribution is a comparison study between synthetic hydroxyapatite (Sy-HAP) and commercial hydroxyapatite (C-HAP) for the removal of Pb2+ and Cd2+ ions present in wastewater from industrial effluents. The obtained results show that the equilibrium time required for complete adsorption of Pb2+ and Cd2+ ions on C-HAP and Sy-HAP is 15 min for both. The obtained removal efficiencies for Sy-HAP are 95.52% and 90.91% for Pb2+ and Cd2+ ions, respectively. Whereas, C-Hap presents lower removal efficiencies of 86.53% and 81.43% for Pb2+ and Cd2+ ions, respectively. Maximum adsorption was observed at pH 5; at lower pH levels adsorption was less. The experimental kinetic data fitted with the second order kinetic model. Thermodynamically, the adsorption process was endothermic and spontaneous in nature. Isotherm adsorption studies indicated that Langmuir, Freundlich and Temkin are the most valid models to describe and evaluate the adsorption process. The EDX results also confirmed the presence of lead and cadmium in adsorbents after adsorption. Finally, the HAP porous materials possess great potential for the removal of Pb2+ and Cd2+ ions from aqueous solutions and wastewater from industrial effluents.

Novel Adsorbent Used for Cesium Removal from Aqueous Solutions

2017 ◽  
Vol 68 (3) ◽  
pp. 470-473
Author(s):  
Corneliu Mircea Davidescu ◽  
Andreea Gabor ◽  
Adina Negrea ◽  
Mihaela Ciopec ◽  
Petru Negrea ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Metal Ion ◽  
Nuclear Power ◽  
Adsorption Process ◽  
Magnesium Silicate ◽  
Polluted Water ◽  
Order Kinetic ◽  
Equilibrium Studies ◽  
Removal Process ◽  
Geological Formation

Cesium (Cs) removal from wastewater becomes an emerging issue after the Fukushima Daiichi Nuclear Power Plant disaster. Cs(I) is an metal ion present in high level radioactive waste and has to be removed for a better disposal in geological formation. The present study investigates the adsorption process of Cs(I) from aqueous solutions on an novel adsorbent material. The novelty of this material is that the solid support, magnesium silicate, is doped with a new extractant, thiourea dissolved in ethyl alcohol. In order to establish the adsorption capacities of the adsorbent material, it was used in the removal process of metal ions. Kinetically, the adsorption process of this metal ion has the best fit for the pseudo-second-order kinetic model. The removal process through adsorption is endothermic and spontaneous due to the thermodynamic studies. Equilibrium studies were also carried out for the Langmuir, Freundlich and Sips model. The new doped material proves to be favourable as adsorbent material in the removal of Cs(I) from polluted water.

scholarly journals Optimization, Equilibrium and Kinetic Modeling of Methylene Blue Removal from Aqueous Solutions Using Dry Bean Pods Husks Powder

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5673
Author(s):  
Giannin Mosoarca ◽  
Simona Popa ◽  
Cosmin Vancea ◽  
Sorina Boran
Keyword(s):  
Methylene Blue ◽  
Taguchi Method ◽  
Aqueous Solutions ◽  
Kinetic Modeling ◽  
Adsorption Process ◽  
Physical Adsorption ◽  
Dye Adsorption ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Dry Bean

In this research, dry bean pods husks (DBPH) were used as an adsorbent material after minimum processing (without chemical substances consumption and without thermal treatment) to remove methylene blue from aqueous solutions. The adsorbent surface characteristics were investigated using SEM and FTIR analysis. For maximum removal efficiency, several parameters that influence the dye adsorption were optimized using the Taguchi method. Equilibrium and kinetic modeling, along with thermodynamic studies, were conducted to elucidate the adsorption mechanism. Taguchi experimental design showed that the factor with the highest influence was the adsorbent dose, with a percent contribution established by the ANOVA analysis of 40.89%. Langmuir isotherm and pseudo-second order kinetic model characterizes the adsorption process. The maximum adsorption capacity, 121.16 (mg g−1), is higher than other similar adsorbents presented in scientific literature. Thermodynamic parameters indicate a spontaneous, favorable and endothermic adsorption process, and their values show that physical adsorption is involved in the process. The obtained results, and the fact that adsorbent material is inexpensive and easily available, indicate that DBPH powder represents an effective absorbent for treating waters containing methylene blue. Additionally, the Taguchi method is very suitable to optimize the process.

scholarly journals Removing lead ions from aqueous solutions by the thiosemicarbazide grafted multi-walled carbon nanotubes

2017 ◽  
Vol 76 (2) ◽  
pp. 302-310 ◽  
Author(s):  
Ying Zhou ◽  
Jingang Yu ◽  
Xinyu Jiang
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solutions ◽  
Adsorption Process ◽  
Lead Ions ◽  
Maximum Adsorption Capacity ◽  
Gravimetric Analysis ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

A novel multi-walled carbon nanotubes (MWCNTs) material functionalized with thiosemicarbazide was synthesized successfully and used to remove lead ions from aqueous solutions. The technologies of Fourier Transform Infrared Spectroscopy, scanning electron microscopy and thermal gravimetric analysis were used to characterize the structure and properties of thiosemicarbazide grafted MWCNTs. The adsorption conditions, such as pH, contact time and temperature, were investigated. The results showed pH affected the adsorption process greatly, and the adsorption process reached equilibrium within 60 min. The maximum adsorption capacity was 42.01 mg/g. The adsorption process fitted well with the pseudo-second-order kinetic model and the Langmuir model. The thermodynamic parameters indicated the adsorption process was endothermic and spontaneous in nature.

scholarly journals Activated Olive Stones as a Low-Cost and Environmentally Friendly Adsorbent for Removing Cephalosporin C from Aqueous Solutions

2021 ◽  
Vol 18 (9) ◽  
pp. 4489
Author(s):  
Gerardo León ◽  
Francisco Saura ◽  
Asunción María Hidalgo ◽  
Beatriz Miguel
Keyword(s):  
Activated Carbon ◽  
Aqueous Solutions ◽  
Adsorption Process ◽  
Low Cost ◽  
Physical Nature ◽  
Freundlich Isotherm ◽  
Mass Transfer Process ◽  
Order Kinetic ◽  
Cephalosporin C ◽  
Olive Stones

In this paper, we describe the removal of cephalosporin C (CPC) from aqueous solutions by adsorption onto activated olive stones (AOS) in a stirred tank. For comparative purposes, several experiments of adsorption onto commercial granular activated carbon were carried out. A quantum study of the different species of cephalosporin C that, depending on the pH, exist in aqueous solution pointed to a favorable mass transfer process during adsorption. Activated olive stones were characterized by SEM, EDX and IR techniques and their pHzc was determined. A 10−3 M HCl cephalosporin C solution has been selected for the adsorption experiments because at the pH of that solution both electrostatic and hydrogen bond interactions are expected to be established between the adsorbate and the adsorbent. The adsorption process is best described by the Freundlich isotherm model and the pseudo-second-order kinetic model, while the adsorption mechanism is mainly controlled by film diffusion. Under the conditions studied, the adsorption process is of a physical nature, endothermic and spontaneous. Comparison of the adsorption results obtained in this paper with those of other authors shows that the efficiency of AOS is 20% of that of activated carbon but 65% higher than that of the XAD-2 adsorbent. Considering its low price, abundance, easy accessibility and eco-compatibility, the use of activated olive stones as adsorbents for the removal of emerging pollutants from aqueous solutions represents an interesting possibility from both the economic and the environmental points of view.

scholarly journals Preparation, Characterization and Application of a Home–made Graphene for the Removal of Congo Red From Aqueous Solutions

2021 ◽  
Author(s):  
Temilolu J. Popoola ◽  
Afamefuna E. Okoronkwo ◽  
Olugbenga O. Oluwasina ◽  
Matthew A. Adebayo
Keyword(s):  
Aqueous Solutions ◽  
Congo Red ◽  
Adsorption Process ◽  
Textile Wastewater ◽  
Order Kinetic ◽  
Adsorption Parameters ◽  
X Ray ◽  
Intraparticle Diffusion Model ◽  
Equilibrium Data ◽  
Textile Wastewater Treatment

Abstract Ethylene diaminetetraacetic acid (EDTA) functionalized graphene was synthesized from Nigerian coal using a chemical exfoliation method and the graphene was applied for the removal of Congo red dye from aqueous solutions. The synthesized coal graphene and the raw coal were characterized using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) spectroscopy, Scanning electron microscopy and Energy (SEM)–Energy dispersive X-ray (EDX) spectroscopy. The SEM data revealed surface roughness which is enhanced in the prepared graphene while the EDX revealed an increase in carbon, the main constituent of graphene, from about 26% in the raw coal to about 80% in the prepared graphene. Various adsorption parameters, such as pH, contact time, concentration of Congo red and temperature, were varied for the removal of the dye using raw coal and the synthesized coal graphene. The Liu isotherm gave the best fit of the equilibrium data than the Langmuir, Freundlich and Dubinin-Radushkevich models. The maximum adsorption capacities of the raw coal and synthesized coal graphene at 25 °C are 109.1 mg/g and 129.0 mg/g, respectively. The Avrami fractional order kinetic model was the best model for description of the kinetic data. The model had the lowest values of standard deviation than the pseudo-first order and pseudo-second order models. The adsorption process of the two materials occurred via two stages as proved by intraparticle diffusion model. The adsorption process of the Congo red removal was spontaneous, feasible and endothermic. The study conclusively revealed the graphene nanomaterial to be a viable adsorbent for textile wastewater treatment.

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