Study on Desorption of Ethanol-Loaded Activated Carbon by Microwave Irradiation under Vacuum Condition

2011 ◽  
Vol 396-398 ◽  
pp. 1825-1831
Author(s):  
Quan Li Feng ◽  
Ming Lei Lian ◽  
Lin Zhuang Ma ◽  
Xue Qian Wang ◽  
Ping Ning

The ideal adsorbed solution (IAS) theory has an advantage that no restriction exists for the type of pure component isotherm. One can choose the isotherm that fits the experimental data best. However, the theory requires a lot of numerical calculation, including numerical integration. This study shows that IAS needs very accurate values of numerical integration when the D-R equation is used as a single component isotherm. The error of numerical integration should be set to be no larger than 10-7. Otherwise the error of numerical calculation will occur, which may increase prediction deviation.

2011 ◽  
Vol 396-398 ◽  
pp. 1809-1812
Author(s):  
Quan Li Feng ◽  
Ming Lei Lian ◽  
Xue Qian Wang ◽  
Ping Ning

The ideal adsorbed solution (IAS) theory has an advantage that no restriction exists for the type of pure component isotherm. One can choose the isotherm that fits the experimental data best. However, the theory requires a lot of numerical calculation, including numerical integration. This study shows that IAS needs very accurate values of numerical integration when the D-R equation is used as a single component isotherm. The error of numerical integration should be set to be no larger than 10-7. Otherwise the error of numerical calculation will occur, which may increase prediction deviation.


2020 ◽  
Vol 27 (3) ◽  
pp. 403-413
Author(s):  
Władysław Kamiński ◽  
Krzysztof Kuśmierek ◽  
Andrzej Świątkowski ◽  
Elwira Tomczak

AbstractThe paper examines single- and multicomponent adsorption onto granular activated carbon. The quantities adsorbed in the study were determined using HPLC with UV detection. The experimental data were analysed using the Langmuir, the Freundlich and the Sips adsorption isotherms. With a single component being adsorbed, high coefficients of determination and low mean square errors indicated that the Sips isotherm fitted the adsorption equilibrium well. Further experiments were carried out using aqueous solutions containing two or three adsorbed components in different proportions. For these solutions, the literature methods of predicting multicomponent equilibrium using single-component data did not yield positive results. Assuming that in the investigated range of concentrations no competitive adsorption occurred, the authors propose a method for calculating the equilibrium concentrations in the liquid phase using the equations obtained for individual components. The results achieved correspond very well to the experimental data.


Author(s):  
Roberto D’Amato ◽  
Anna Donnadio ◽  
Mariolino Carta ◽  
Claudio Sangregorio ◽  
Riccardo Vivani ◽  
...  

Reaction of cerium ammonium nitrate and tetrafluoroterephthalic acid in water afforded two new metal-organic frameworks with UiO-66 [F4_UiO-66(Ce)] and MIL-140 [F4_MIL-140A(Ce)] topologies. The two compounds can be obtained in the same experimental conditions, just by varying the amount of acetic acid used as crystallization modulator in the synthesis. Both F4_UiO-66(Ce) and F4_MIL-140A(Ce) feature pores with size < 8 Å, which classifies them as ultramicroporous. Combination of X-ray photoelectron spectroscopy and magnetic susceptibility measurements revealed that both compounds contain a small amount of Ce(III), which is preferentially accumulated near the surface of the crystallites. The CO<sub>2</sub> sorption properties of F4_UiO-66(Ce) and F4_MIL-140A(Ce) were investigated, finding that they perform better than their Zr-based analogues. F4_MIL-140A(Ce) displays an unusual S-shaped isotherm with steep uptake increase at pressure < 0.2 bar at 298 K. This makes F4_MIL-140A(Ce) exceptionally selective for CO<sub>2</sub> over N<sub>2</sub>: the calculated selectivity, according to the ideal adsorbed solution theory for a 0.15:0.85 mixture at 1 bar and 293 K, is higher than 1900, amongst the highest ever reported for metal-organic frameworks. The calculated isosteric heat of CO<sub>2 </sub>adsorption is in the range of 38-40 kJ mol<sup>-1</sup>, indicating a strong physisorptive character.


2006 ◽  
Vol 62 (6) ◽  
pp. 1025-1030 ◽  
Author(s):  
Razvan Caracas ◽  
Renata M. Wentzcovitch

Density functional theory is used to determine the possible crystal structure of the CaSiO3 perovskites and their evolution under pressure. The ideal cubic perovskite is considered as a starting point for studying several possible lower-symmetry distorted structures. The theoretical lattice parameters and the atomic coordinates for all the structures are determined, and the results are discussed with respect to experimental data.


2006 ◽  
Vol 53 (11) ◽  
pp. 251-260 ◽  
Author(s):  
H. Tsuno ◽  
M. Kawamura ◽  
T. Oya

An expanded-bed anaerobic reactor with granular activated carbon (GAC) medium has been developed to treat wastewaters that contain a high concentration of inhibitory and/or refractory organic compounds as well as readily degradable organic compounds. The process is characterised by a combination of two removal mechanisms; adsorption on GAC and biological degradation by microorganisms grown on GAC. Applicability of the reactor to treatment of phenol, chloroacetaldehyde (CAA), pentachlorophenol (PCP) and tetrachloroethylene (PCE) was discussed based on experimental data. All chemicals focused on here were removed well and stably at a removal efficiency of more than 98% even during starting operation and shock load operation. Chemicals in influent that exceeded biological degradation capacity was initially adsorbed on GAC and then gradually degraded, and hence the adsorptive capacity of GAC was regenerated biologically. These results proved that a biological activated carbon anaerobic reactor was effective for treatment of wastewater containing hazardous chemicals, especially for strongly absorbable chemicals, as well as readily degradable organic compounds at high concentration.


2017 ◽  
Vol 19 (4) ◽  
pp. 59-64 ◽  
Author(s):  
Dorota Downarowicz ◽  
Katarzyna Ziętarska

Abstract The study examined the adsorption of propan-1-ol (1PN) vapour on Sorbonorit 4 (S4) activated carbon in cyclic Electrothermal Temperature Swing Adsorption (ETSA) process. Dynamic adsorption capacity and breakthrough time were determined based on column studies. Thomas model was used to describe experimental breakthrough curves. Adsorption isotherms for 1PN vapour on S4 activated carbon were tested at 293 to 413 K. The experimental data were examined by using three multi-temperature isotherm models: Toth, Sips and hybrid Langmuir-Sips. Results indicate that S4 activated carbon is a heterogeneous adsorbent and the hybrid Langmuir-Sips model provides the best-fit experimental data. The energy requirement for 1PN electrothermal desorption from S4 bed (ca. 170–200 kJ/mol) was about 3 to 3.5 times larger than the isosteric heat of adsorption (56.8 kJ/mol), which was calculated using Toth adsorption isotherm.


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