scholarly journals Studies of Dye Sensitisation Kinetics and Sorption Isotherms of Direct Red 23 on Titania

2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
Peter J. Holliman ◽  
Beatriz Vaca Velasco ◽  
Ian Butler ◽  
Maarten Wijdekop ◽  
David A. Worsley
Keyword(s):  
Sorption Isotherms ◽  
Freundlich Isotherm ◽  
Zero Point ◽  
Sorption Kinetics ◽  
X Ray Diffraction ◽  
Dye Sensitization ◽  
Sorption Data ◽  
Charge Analysis ◽  
Uptake Data ◽  
Kinetics And Isotherms

Sorption kinetics and isotherms have been measured for a commercial dye (Direct Red 23) on different samples of powdered Titania, and the data were analysed to better understand the dye sensitization process for dye sensitised solar cells (DSSCs). For the sorption kinetics, the data show rapid initial sorption (<1 hour) followed by slower rate of increasing uptake between 1 and 24 hours. While higher initial concentrations of dye correspond to higher sorption overall, less dye is absorbed from higher initial dye concentrations when considered as percentage uptake. The correlation between the sorption data and model isotherms has been considered with time. The Langmuir model shows better correlations compared to the Freundlich isotherm. The dye uptake data has also been correlated with Titania characterization data (X-ray diffraction, scanning electron microscopy, BET and zero point charge analysis). Kinetic data show significantly better fits to second-order models compared to first order. This suggests that chemisorption is taking place and that the interaction between the dye sorbate and the Titania sorbent involves electron sharing to form an ester bond.

scholarly journals Sorption of Ni(II) and Cr(III) ions by the Chironomus yoshimatsui larvae from wastewater

2018 ◽  
Vol 15 (1) ◽  
pp. 6062-6069
Author(s):  
Keon Sang Ryoo
Keyword(s):  
Freundlich Isotherm ◽  
Sorption Kinetics ◽  
Isotherm Model ◽  
Sorption Data ◽  
First Order ◽  
Batch System ◽  
Survival Capacity ◽  
Langmuir Isotherm Model ◽  
Treatment Technologies ◽  
Kinetics Of

In this study, Chironomus yoshimatsui larvae were applied to remove Ni(II) and Cr(III) ions from wastewater. The sorption studies were carried out using laboratory-reared C. y. larvae. It was found that C. y. larvae are very susceptible to Cr(III) as compared to Ni(II). The survival capacity of C. y. larvae was sharply reduced when exposed to even low Cr(III) concentration. Sorption isotherm and kinetics of C. y. larvae for Ni(II) were determined by means of controlled experiments in a batch system. It was observed that sorpyion efficiency of Ni(II) was largely concentration dependent and more effective at lower concentration. At each equilibrium, Ni(II) was removed up to roughly 44∼80 %. Sorption data were better fitted to the Langmuir isotherm model because of its correlation coefficient R2 value greater than that of the Freundlich isotherm model. The sorption kinetics by C. y. larvae for Ni(II) was well described a pseudo-first-order rate expression. C. y. larvae have enormous potential for application in wastewater treatment technologies because they are widespread and abundant all around the world and can be easily kept in culture.

scholarly journals Engineering Functionalized Chitosan-Based Sorbent Material: Characterization and Sorption of Toxic Elements

2019 ◽  
Vol 9 (23) ◽  
pp. 5138 ◽  
Author(s):  
Adnan Khan ◽  
Nisar Ali ◽  
Muhammad Bilal ◽  
Sumeet Malik ◽  
Syed Badshah ◽  
...  
Keyword(s):  
Experimental Data ◽  
Sorption Isotherms ◽  
Analytical Techniques ◽  
Aqueous Environment ◽  
X Ray Diffraction ◽  
Sorption Data ◽  
Regression Methods ◽  
Sorbent Material ◽  
Lead And Cadmium ◽  
Cadmium And Lead

The present study reports the engineering of functionalized chitosan (CH)-based biosorbent material. Herein, a two-step reaction was performed to chemically modify the CH using 1,4-bis(3-aminopropyl) piperazine to incorporate nitrogen basic centers for cations sorption from the aqueous environment. The resultant functionalized chitosan-based sorbent material was designated as CH-ANP and characterized using various analytical techniques, including elemental analysis, Fourier-transform infrared spectroscopy (FTIR), 13C NMR (in solid-state), X-ray diffraction, and thermal analysis. Then, the newly engineered CH-ANP was employed for the removal of copper, lead, and cadmium in the aqueous medium. Langmuir sorption isotherm analysis revealed that the highest sorption abilities achieved were 2.82, 1.96, and 1.60 mmol g−1 for copper, cadmium, and lead, respectively. Linear and nonlinear regression methods were deployed on the sorption data to study the behavior of the Langmuir, the Freundlich, and the Temkin sorption isotherms. Among the four different forms, the Langmuir isotherm type 1 fit well to the experimental data as compared to the other models. It also showed the lowest values of error, and a higher correlation coefficient than the Freundlich and Temkin models; thus it was the best fit with the experimental data compared to the latter two models. In conclusion, the findings suggest that chemically modified novel materials with enhanced Lewis basic centers are useful and promising candidates for the sorption of various toxic cations in aqueous solution.

Coating Iron Oxides on Kaolinite for the Adsorption of Fluoride

2012 ◽  
Vol 479-481 ◽  
pp. 250-254
Author(s):  
Wen Jun Xiang
Keyword(s):  
Iron Oxides ◽  
Freundlich Isotherm ◽  
Zero Point ◽  
Bet Surface Area ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fluoride Adsorption ◽  
Adsorption Data ◽  
Co Precipitation

Iron oxides-coated kaolinite (Fe-Kaolinite) was prepared by co-precipitation and indentified using X-ray diffraction (XRD). Moreover, the surface properties and fluoride adsorption characteristics of Fe-Kaolinite were investigated and compared with those of kaolinite. Compared to kaolinite, the BET surface area and surface fractal dimension of Fe-Kaolinite increased significantly. The pH at zero point of charge (pHZPC) of kaolinite and Fe-Kaolinite was 3.16 and 6.24, respectively. In the suspensions of pH 6.0, the fitted maximum adsorption capacity (qmax) for fluoride of kaolinite and Fe-Kaolinite was 1.32 and 5.86 mg/g, respectively. The adsorption data for fluoride by Fe-Kaolinite could be fitted using Freundlich isotherm (R2 =0.987), and Langmuir isotherm was very suitable for describing the fluoride adsorption of kaolinite (R2 =0.991).

scholarly journals Sorption and wetting properties of pectin edible films

2012 ◽  
Vol 30 (No. 5) ◽  
pp. 446-455 ◽  
Author(s):  
S. Galus ◽  
A. Turska ◽  
A. Lenart
Keyword(s):  
Water Vapour ◽  
Sorption Isotherms ◽  
Sorption Kinetics ◽  
Edible Films ◽  
Glycerol Concentration ◽  
Water Vapour Sorption ◽  
Vapour Sorption ◽  
Vapour Adsorption ◽  
Water Vapour Adsorption ◽  
Kinetics And Isotherms

The water vapour sorption kinetics and isotherms of pectin films prepared by the casting method were determined. The measurement of water vapour sorption kinetics was conducted using a saturated sodium chloride solution to obtain constant relative humidity of the environment (75.3%). The measurement was carried out at the temperature of 25&deg;C over a 24 h period. The water vapour adsorption rate was the highest in the first hours of the process. The exponential equation fitted well the experimental data of water vapour adsorption with time. Glycerol concentration in the analysed films affected the increasing water vapour adsorption. The water vapour sorption isotherms were analysed using the saturated salt solutions with water activity from 0.113 to 0.901 for 3 months at 25&deg;C. The sorption isotherms curves had a sigmoidal shape for all films. Glycerol content affected water vapour adsorption during 3 months. Peleg&rsquo;s equation was appropriate for the mathematical description of the sorption isotherms. The microstructure of pectin films showed different internal arrangement as a function of the film composition. &nbsp;

scholarly journals Sulfamethoxazole sorption in eutrophic Regolithic Neosol

2018 ◽  
Vol 22 (7) ◽  
pp. 506-510
Author(s):  
Márcia A. M. F. de Barros ◽  
Antônio C. D. Antonino ◽  
Alexandre R. P. Schuler ◽  
José R. de S. Lima ◽  
Manuella V. S. Gondim ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Organic Matter ◽  
High Performance ◽  
Sorption Isotherms ◽  
Sorption Kinetics ◽  
Sorption Experiment ◽  
Batch Method ◽  
Order Model ◽  
Analytical Curve ◽  
Kinetics And Isotherms

ABSTRACT This study aimed to evaluate sulfamethoxazole sorption kinetics and isotherms using batch method. The experiment was carried out in typic eutrophic Regolithic Neosol (0-20 and 20-60 cm layers) located in the private reserve of the Riacho do Papagaio farm, in São João, PE, Brazil. The tests were carried out under laboratory conditions at 24 ºC and sulfamethoxazole concentration was determined by high-performance liquid chromatography. The sorption experiment through the batch method used sulfamethoxazole solutions with concentrations of 10-3, 5.10-4, 10-4, 5.10-5, 10-5 and 5.10-6 mol L-1 to obtain the analytical curve. For this soil, sulfamethoxazole sorption kinetics was best described by a second-order model and the sorption isotherms were linear. Sulfamethoxazole predominantly interacts with organic matter in this type of soil. The results obtained in this study show that the antibiotic sulfamethoxazole exhibits low adsorption, posing a higher risk of contamination to the groundwaters in this region at pH ≈ 7.

Preparation of xanthated bentonite and its removal behavior for Pb(II) ions

2010 ◽  
Vol 61 (5) ◽  
pp. 1235-1243 ◽  
Author(s):  
Y. F. He ◽  
F. R. Li ◽  
R. M. Wang ◽  
F. Y. Li ◽  
Y. Wang ◽  
...  
Keyword(s):  
Adsorption Mechanism ◽  
Removal Rate ◽  
Freundlich Isotherm ◽  
Particle Size Analysis ◽  
Lead Ions ◽  
Size Analysis ◽  
Optimum Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir

Xanthate was successfully grafted onto bentonite by a relatively simple solution reaction. The obtained xanthated bentonite (XBent) was characterized by FT-IR spectrophotometer, thermogravimetric analysis (TG), particle size analysis, x-ray diffraction (XRD) and scanning electron microscopy (SEM). XBent acting as a type of environmentally friendly adsorbent was applied to remove lead ions from aqueous solutions. The optimum conditions were as follows: [Pb2 + ] = 500 mg L−1, [XBent] = 2 g L−1, pH = 5.0; oscillating 60 min under 200 rpm at 25°C. The removal rate of lead was up to 99.9%. It was found that the lead(II) ions—XBent adsorption isotherm model fitted well to the Freundlich isotherm. The adsorption mechanism was also investigated by SEM and XRD, which concluded that lead ions were complexed or chelated with XBent. XBent appears to have potential to be used later in water treatment as a type of inorganic polymer reagent.

scholarly journals The Removal of Methylene Blue Dye from Aqueous Solutions Using Activated and Non-Activated Bentonites

2003 ◽  
Vol 21 (5) ◽  
pp. 451-462 ◽  
Author(s):  
Sameer Al-Asheh ◽  
Fawzi Banat ◽  
Leena Abu-Aitah
Keyword(s):  
Methylene Blue ◽  
Ph Value ◽  
Sodium Dodecyl ◽  
Freundlich Isotherm ◽  
Blue Dye ◽  
Batch Adsorption ◽  
Ionic Surfactant ◽  
Methylene Blue Dye ◽  
X Ray Diffraction ◽  
Initial Ph

An improvement in the adsorption capacity of naturally available bentonite towards water pollutants such as Methylene Blue dye (MBD) is certainly needed. For this purpose, sodium bentonite was activated by two methods: (1) treatment with sodium dodecyl sulphate (SDS) as an ionic surfactant and (2) thermal treatment in an oven operated at 850°C. Batch adsorption tests were carried out on removing MBD from aqueous solution using the above-mentioned bentonites. It was found that the effectiveness of bentonites towards MBD removal was in the following order: thermal-bentonite > SDS-bentonite > natural bentonite. X-Ray diffraction analysis showed that an increase in the microscopic bentonite platelets on treatment with SDS was the reason behind the higher uptake of MBD. An increase in sorbent concentration or initial pH value of the solutions resulted in a greater removal of MBD from the solution. An increase in temperature led to an increase in MBD uptake by the bentonites studied in this work. The Freundlich isotherm model was employed and found to represent the experimental data well.

Experimental and computational investigations of TiIrB: a new ternary boride with Ti1+x Rh2−x+y Ir3−y B3-type structure

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jan P. Scheifers ◽  
Kate A. Gibson ◽  
Boniface P. T. Fokwa
Keyword(s):  
Density Functional ◽  
Ternary Phase ◽  
Structure Type ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
Arc Melting ◽  
Ternary Boride ◽  
Charge Analysis ◽  
First Time ◽  
Bader Charge Analysis

Abstract A new ternary phase, TiIrB, was synthesized by arc-melting of the elements and characterized by powder X-ray diffraction. The compound crystallizes in the orthorhombic Ti1+x Rh2−x+y Ir3−y B3 structure type, space group Pbam (no. 55) with the lattice parameters a = 8.655(2), b = 15.020(2), and c = 3.2271(4) Å. Density Functional Theory (DFT) calculations were carried out to understand the electronic structure, including a Bader charge analysis. The charge distribution of TiIrB in the Ti1+x Rh2−x+y Ir3−y B3-type phase has been evaluated for the first time, and the results indicate that more electron density is transferred to the boron atoms in the zigzag B4 units than to isolated boron atoms.

Acid Hydrolysis Lignin as a Sorbent for Naphthalene

2001 ◽  
Vol 36 (4) ◽  
pp. 719-735 ◽  
Author(s):  
Angela Keane ◽  
Subhasis Ghoshal
Keyword(s):  
Organic Matter ◽  
Acid Hydrolysis ◽  
Waste Product ◽  
Freundlich Isotherm ◽  
Packed Bed ◽  
Hydrolysis Lignin ◽  
Sorptive Capacity ◽  
Sorption Data ◽  
Large Pressure ◽  
Acid Hydrolysis Lignin

Abstract Lignin, a major polymeric constituent of woody plant tissue, is an abundant source of natural organic matter available as a waste product from the pulp and paper and the fuel ethanol industries. In this study, the sorptive capacity of acid hydrolysis lignin for naphthalene, a representative nonpolar hydrophobic organic compound (HOC), was investigated. When powdered lignin is mixed with distilled water, dissolved and/or colloidal organic matter leaches into the aqueous phase imparting a cloudy yellowish colour. A washing and filtering protocol was developed for pretreating the lignin employed in the sorption studies. Results from batch sorption experiments showed that acid hydrolysis lignin has a strong affinity for naphthalene. The Freundlich isotherm coefficients obtained indicate that the sorption isotherm for naphthalene on hydrolysis lignin is nearly linear. A modified Freundlich equation was employed in order to compare sorption data for HOCs on lignin and activated carbon through the use of unit equivalent coefficients. The results presented in this research and in the literature suggest that the two sorbents are comparable in terms of sorption coefficients. It was determined that acid hydrolysis lignin is unsuitable for use in a packed bed since pumping a naphthalene solution through a column packed with lignin caused the wet lignin to become significantly hardened over time, resulting in a large pressure drop across the system.

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