Adsorption Pore Volume Research Articles

활성탄으로 코팅된 집진전극의 BTEX 흡착특성

This study was performed to provide the basic data for the function of BTEX removal for compact electrostatic precipitator which are applicable to indoor environment (or closed spaces). For this purpose, the adsorption equilibrium test was conducted for BTEX of activated carbon sheet (ACS) and activated carbon (AC), and the adsorption characteristics of AC and ACS were evaluated using the Langmuir constant which was obtained from the adsorption characteristics, adsorption capacity and regression calculation. The surface area and adsorption pore volume of ACS reduced by 70% and 86%, respectively, as compared to those of AC, and the adsorption capacities of BTEX also showed a similar level. Thus, it is considered that ACS applied electrostatic precipitator is able to remove dust and BTEX simultaneously.

A Highly Efficient Activated Carbon by Chemical Activation Method for Adsorption of Paraquat (Toxin)

The optimum condition for preparing a highly efficient activated carbon has been investigated in this work. The effects of different activation temperatures on the pore structure and surface morphology of highly efficient activated carbon (AC) derived from waste palm shell by chemical activation method using phosphoric acid as activating agent were studied. For activation, different activation temperatures in the range of 550 °C-650 °C were carried out. Activated carbon with well developed pore size were produced at activation temperature of 600 °C for 2 hours. At this temperature the Brunauer , Emmett and Teller (BET) surface areas are 1287 m2g-1, the total pore volume for adsorption and desorption are 0.742 cm3 g-1. Scanning Electron Microscope also confirmed the porosity of the highly efficient activated carbon. Finally it was tested in vitro to determine its adsorbing capacity for paraquat as a toxin. For optimum adsorption ability of activated carbon for paraquat, 0.9% NaCl solution is the most suitable solvent. The paraquat preferentially adsorbed onto the activated carbon in NaCl solution. The adsorption ability of the activated carbon (the amount adsorbed) for paraquat observed to be 99.9 mg g-1.

EFFICIENCY OF ACTIVATED CARBON REGENERATION AFTER THE LONG-TERM EXPLOITATION IN FILTERS FOR TAP WATER POST-TREATMENT

Predominately mesoporous structured activated carbon is the best sorbent for the natural organic matter extraction from water. Mesoporous activated carbons KAU, KAU-TF and BAU were used in the adsorption filters for tap water post-treatment for a long time (more than three years). Structural-adsorptive characteristics of these carbons were estimated in the paper. The spontaneous bioregeneration takes place on the activated carbon surface. It is caused by the biofilm formation during water filtration in non-sterile conditions. As a result of this process active carbon adsorption parameters are restored, namely the part of the AC unoccupied total specific surface area is 61,1-82,9 % of the initial value, the part of the unoccupied total adsorption pore volume is 59,0-87,2 %, whereas the value of unoccupied effective supermicro- and mesopores surface can be up to 69,3-98,2%. Active carbon samples treatment with sodium hydroxide leads to a partial release of the micropores adsorption volume especially in the lower carbon bed layers by water passing. Spontaneous activated carbon bioregeneration under filtration of ozonated tap water runs more efficiently than bioregeneration after a non-ozonated water filtration under the same organic matter load on the AC. Efficiency improving of spontaneous bioregeneration after a pre-ozonated tap water filtration is caused by the transformation of organic substances molecules into a form that is more accessible to the functioning of native biofilm.

The effect of polyethylene glycol molecular weight on characteristics of the porous structure of silica materials

The effect of poly(ethylene glycol) (PEG) chain length on textural properties had been investigated. It is shown that mesoporous and microporous silica materials can be prepared based on PEG and TEOS. At fixed molar concentration of polymer using the PEG-1300 mesoporous silica material is formed but when increasing molecular weight to 3000—microporous silica material. With further increasing of the molecular weight of PEG to 20000 the micropore volume and total adsorption pore volume remain almost unchanged, so starting with a specific length of the PEG macromolecule the effect of molecular weight on the texture of the formed SiO2 becomes negligible. Based on the approach taken and the results we proved the possibility of purposeful control of the texture of silica materials.

Adsorption of carbon dioxide and nitrogen on zeolite rho prepared by hydrothermal synthesis using 18-crown-6 ether

Zeolite rho was prepared by hydrothermal synthesis using an 18-crown-6 ether (18C6) as a structure-directing agent, and the effects of the calcination temperature for removal of 18C6 on the physicochemical properties and CO2-adsorption properties were investigated. CO2 adsorption on zeolite rho calcined at 150°C was lower than that on samples calcined at temperatures above 300°C. For samples calcined above 300°C, CO2 adsorption increased with increasing calcination temperature up to 400°C. It is thought that the pore volume for adsorption of CO2 increased as a result of 18C6 removal, resulting in increasing CO2 adsorption. A decrease in CO2 adsorption for calcination from 400°C to 500°C was observed. The particle size of zeolite rho increased with increasing 18C6 molar ratio. Particle sizes of 1.0–2.1μm and 1.4–2.6μm were found by field-emission scanning electron microscopy and dynamic light-scattering, respectively. The particle size is controlled in these regions by adjusting the 18C6 molar ratio. XRD showed that zeolite rho samples with 18C6 molar ratios of 0.25–1.5 had high crystallinity. The adsorbed amount of CO2 is almost constant, at 3.4mmol-CO2g−1, regardless of the 18C6 molar ratio. However, CO2 selectivity, which is the CO2/N2 adsorption ratio, decreased. The amount of CO2 adsorbed on zeolite rho is lower than that on zeolite NaX, but higher than that on SAPO-34. The CO2/N2 adsorption ratio for zeolite rho was higher than those for SAPO-34 and zeolite NaX.

Adsorption of Protein from Model Wine Solution by Different Bentonites

The adsorption of protein from model wine was investigated under different temperatures, pH values, contact times, and concentrations of ethanol, by certain bentonites. The results showed that ethanol molecules could broaden the protein molecules' channel to the interlayer of bentonite, and the maximum protein adsorption amount occurred under an ethanol concentration of 12% (by volume) and a pH value of 3.56. The increased single point Brunauer-Emmitt-Teller (BET) surface area (S BET) and adsorption pore volume ( V Ads) suggested a larger amount of active adsorption sites of the bentonite surface and a wider protein channel from the surface to the inner adsorption sites of bentonite, respectively. At the same time, higher methylene blue test (MBT) and swelling index (Sw) indicated that it was easy for the entrance of water and the absorbance of protein. Higher temperature was found favorable to eliminate more proteins and it took about 20 to 40min to arrive at the maximum adsorption.

Assessment of ordered and complementary pore volumes in polymer-templated mesoporous silicas and organosilicas

A method to determine the volumes of ordered mesopores and complementary small pores in polymer-templated ordered mesoporous silicas and organosilicas is proposed on the basis of the existing relation between the pore width and unit cell values obtained by the XRD structure modeling and the adsorption pore volume.

Use of Dubinin–Astakhov Equation to Describe Preloading Effect of Natural Organic Matter

This note presents a simple model to quantify the preloading effect of naturally occurring organic matter (NOM) in water on the adsorption capacity of activated carbon for a trace synthetic organic chemical (SOC). The model was developed from the Dubinin–Astakhov (DA) equation based on the assumption that the NOM preloading irreversibly reduced the limiting adsorption pore volume for the target SOC. Given that the DA-\in value equal to one, the model reduces to a form similar to the one obtained by modifying the Freundlich equation directly. By assuming that the reduction of the limiting adsorption pore volume was proportional to the volume of NOM adsorbed, the NOM preloading effect was correlated directly to the amount of total organic carbon preloaded on the carbon. The resulting model was then compared with the experimental data in the literature. This simple model may be useful for certain practical applications that require only the estimation of the NOM preloading effect on the adsorption capacity of a target SOC from natural water.

Effect of the pore sizes of nylon affinity membranes on γ-globulin adsorption

l-Phenylalanine was immobilized on nylon membranes with two pore diameters (0.45 μm and 1 μm), by activation with 1,4-butanediol diglycidyl ether, and the effect of pore size on the affinity adsorption of γ-globulin studied by batch and kinetic methods. Experiment shows that adsorption on both affinity membranes obeys the Freundlich model. The accessible pore volume for adsorption of proteins on the membrane with 0.45 μm diameter pores is less than for that with 1 μm diameter pores. The adsorption capacity of affinity membranes with 1 μm diameter pores is 2.5-fold that of membranes with 0.45 μm diameter pores. Feed-rate has a larger effect on affinity adsorption on the membrane with 0.45 μm diameter pores than on that with 1 μm diameter pores. Small pores on the affinity membrane do not cause broadening of the elution peak. It is concluded that affinity interaction and separation occur mainly in the large pores, and small pore size does not favor improvement of adsorption capacity. γ-Globulin 85.1% pure can be obtained in one step from human plasma by use of the affinity membrane with 0.45 μm diameter pores.