Study of Static Adsorption Capacity of ACF for Xenon at 201 K

The static adsorption performances of a series of active carbon fiber(ACF)for xenon at 201 K were measured with a model ASAP2010M specific surface area and aperture distribution instrument by changing the working gas of instrument from N 2 to Xenon. Compared with grain active carbon(GAC): (1) the adsorption performance of Viscose based ACF(VACF) adsorbents is better than that of GAC; (2) owing to the difference of aperture distribution, the adsorption performance of ACF with different radicales is different under the same experiment conditions though the specific surface area is similar; (3) there is no definite relationship between adsorption performance and specific surface area; (4) the VACF A2 is the superior xenon adsorbent at the experimental temperature.

Adsorption Capacity for Phosphorus Comparison among Activated Alumina, Silica Sand and Anthracite Coal

Experimental researches on adsorptive capacity of activated alumina, silica sand and anthracite coal for phosphorus were conducted. Results showed that performances of three filter media were all in line with Langmuir isotherm, and activated alumina adsorptive performance was much better than silica sand and an-thracite coal for phosphorus removal. The adsorptive capacity of activated alumina, silica sand and anthracite coal for phosphorus was 3333μg/g, 49μg/g and 100μg/g respectively. Activated alumina displayed adsorp-tive function well for phosphorus, because its inner porosity, specific surface area and surface isoelectric pH value were all higher than those of other two filter media. While activated alumina was used as filter material in water treatment process, phosphorus would be removed strongly because of adsorptive characteristic of activated alumina.

Combined control of fluid adsorption capacity and initial permeability on coal permeability

The variations of strain and permeability of coal were systematically studied through the physical simulation of N2 and water injection.The effects of fluid adsorption capacity and initial permeability on strain,permeability and the dominant effect of pore pressure were discussed.The adsorption strain and strain rate of coal during water injection are significantly higher than those during N2 injection.An edge of free adsorption exists in the early phase of N2 and water injection,which is related to fluid saturation.Within this boundary,the strain rate and pore pressure are independent.Moreover,the injec-tion time of initial stage accounts for about 20%of the total injection time,but the strain accounts for 70%of the total strain.For water injection,this boundary is about half of water saturation of coal.Besides,the influence of pore pressure on permeability is complex,which is controlled by adsorption capacity and initial permeability of coal.When the initial permeability is large enough,the effect of adsorption strain on permeability is relatively weak,and the promoting effect of pore pressure on fluid migration is dominant.Therefore,the permeability increases with increasing pore pressure.When the initial permeability is relatively low,the pore pressure may have a dominant role in promoting fluid migration for the fluid with weak adsorption capacity.However,for the fluid with strong adsorption capacity,the adsorption strain caused by pore pressure may play a leading role,and the permeability reduces first and then ascends with increasing pore pressure.

Investigation of methane adsorption on chlorite by grand canonical Monte Carlo simulations

In this paper, the methane adsorption behaviours in slit-like chlorite nanopores were investigated using the grand canonical Monte Carlo simulation method, and the influences of the pore sizes, temperatures, water, and compositions on methane adsorption on chlorite were discussed. Our investigation revealed that the isosteric heat of adsorption of methane in slit-like chlorite nanopores decreased with an increase in pore size and was less than 42 kJ/mol, suggesting that methane adsorbed on chlorite through physical adsorption. The methane excess adsorp- tion capacity increased with the increase in the pore size in micropores and decreased with the increase in the pore size in mesopores. The methane excess adsorption capacity in chlorite pores increased with an increase in pressure or decrease in pore size. With an increase in temperature, the isosteric heats of adsorption of methane decreased and the methane adsorption sites on chlorite changed from lower- energy adsorption sites to higher-energy sites, leading to the reduction in the methane excess adsorption capacity. Water molecules in chlorite pores occupied the pore wall in a directional manner, which may be related to the van der Waals and Coulomb force interactions and the hydrogen bonding interaction. It was also found that water molecules existed as aggregates. With increasing water content, the water molecules occupied the adsorption sites and adsorption space of the methane, leading to a reduction in the methane excess adsorption capacity. The excess adsorption capacity of gas on chlorite decreased in the following order： carbon dioxide 〉 methane 〉 nitrogen. If the mole fraction of nitrogen or carbon dioxide in the binary gas mixture increased, the mole fraction of methane decreased, methane adsorption sites changed, and methane adsorption space was reduced, resulting in the decrease in the methane excess adsorption capacity.

Facile In Situ Fabrication of Nanostructured Graphene–CuO Hybrid with Hydrogen Sulfide Removal Capacity

A simple and scalable synthetic approach for one-step synthesis of graphene–Cu O(TRGC) nanocomposite by an in situ thermo-annealing method has been developed.Using graphene oxide(GO) and copper hydroxide as a precursors reagent,the reduction of GO and the uniform deposition of in situ formed Cu O nanoparticles on graphene was simultaneously achieved.The method employed no solvents,toxic-reducing agents,or organic modifiers.The resulting nanostructured hybrid exhibited improved H2 S sorption capacity of 1.5 mmol H2S/g-sorbent(3 g S/100 g-sorbent).Due to its highly dispersed sub-20 nm Cu O nanoparticles and large specific surface area,TRGC nanocomposite exhibits tremendous potential for energy and environment applications.

Adsorption of Anthraquinone Dyes from Aqueous Solutions by Penicillium Terrestre

Penicillium terrestre was used for removing four anthraquinone dyes from aqueous solution. The experiments were performed in Erlenmeyer flasks and spore suspension was used for inoculation. The results show that the mechanism of dye removal by penicillium terrestre is biosorption and the growing pellets exhibit higher adsorptive capacity than the resting or dead ones. The maximum removals of disperse blue 2BLN, reactive brilliant blue KN-R, acid anthraquinone blue and bromamine acid at the concentration of 120 mg/L by biosorptionof growing pellets are 10096, 100%, 96% and 91%, respectively. The 100.0% and 91.4% KN-R removals are achieved respectively at the much higher concentration of 250 and 400 mg/L. 2.5 g/L glucose is sufficient for 100% KN-R removal by growing pellets. Salinity （NaCl） increase from 0 to 2% （W/ V） moderately accelerates both mycelium growth and KN-R removal.

Impact of Montmorillonite and Calcite on Release and Adsorption of Cyanobacterial Fatty Acids at Ambient Temperature

Minerals might act as important sorbents of sedimentary organic matter and reduce biodegradation, which favors the formation of hydrocarbon source rocks in the earth＇s history. Since most organic matter is degraded during the sinking process, at ambient temperature, it is important to investigate the adsorption capacity of different minerals during this process, to assess the organic loss from primary productivity to sedimentary organic matter. In this study, montmorillonite and calcite have been selected to study the impact of different minerals on the release, adsorption, and deposition of cyanobacterial （Synechococcus elonpata） fatty acids （FAs） at ambient temperature. Gas chromatography （GC）, gas chromatography-mass spectrometry （GC-MS） have been utilized to detect the variation in fatty acids. Primary results suggest that minerals have a different impact on dissolved organic matter. Montmorillonite can specifically enhance the release of fatty acids from cyanobacterial cells by lowering the pH values of the solution. The adsorption of the dissolved organic matter by montmoriilonite will also be enhanced under a lower pH value. Conjunction of fatty acids with montmoriilonite to form a complex will favor the sinking and preservation of these organics. Selective adsorption is observed among fatty acids with different carbon numbers. In contrast, calcite does not show any impact on the release and adsorption of organic matter even though it is reportedly capable of acting as a catalyst during the transformation of organic matter at high temperature. The primary data bridge a link between primary productivity and sedimentary organic matter, suggesting the relative importance of claystones in the formation of hydrocarbon source rocks in the earth＇s history.

Lysozyme adsorption to cation exchanger derivatized by sequential modification of poly(ethylenimine)-Sepharose with succinic anhydride and ethanolamine: Effect of p H and ionic strength

In our previous work, a series of polyethylenimine(PEI)-derived cation exchangers were synthesized using PEIgrafted resin FF-PEI-L740(ionic capacity, 740 mmol·L^-1) as the basic resin to study lysozyme adsorption and chromatographic behavior. It was found that the resin with an ionic capacity of 630 mmol·L^-1(FF-PEI-CR630)possessed high adsorption performance towards lysozyme at 0–100 mmol·L^-1 Na Cl. Therefore, in this work,FF-PEI-CR630 was selected to study the influences of pH and ionic strength(IS) on protein adsorption and chromatographic behavior towards lysozyme. The increase of lysozyme adsorption capacity in the pH range of 6 to 10 was observed. However, the uptake rate decreased in the pH range of 6 to 8 and then remained essentially unchanged from pH 8 to pH 10. Increasing IS led to decreased protein adsorption capacity and increased uptake rate in different pH ranges. Besides, FF-PEI-CR630 maintained dynamic binding capacity as high as over150 mg·ml^-1 at pH 8–10 without NaCl. The research has thus provided insight into the selection of proper pH and IS conditions for protein purification by using FF-PEI-CR630.

Implications from γ-globulin adsorption onto cation exchangers fabricated by sequential alginate grafting and sulfonation

Our previous work proved that high adsorption capacity and uptake rate of lysozyme were achieved on alginate(Alg)-grafted re sin with an ionic capacity(IC) of 240 mmol·L^(-1)(Alg-FF-240).Moreover,the salt-tolerant feature of Alg-FF-230 was improved by using sequential alginate grafting and sulfonation strategy.Inspired by the enhanced adsorption performance of lysozyme,we have herein proposed to investigate the static and dynamic adsorption behaviors of γ-globulin on a series of Alg-grafted resins with different grafting densities and sulfonation degrees.The adsorption ca pacity of γ-globulin decreased with increa sing alginate-grafting density(IC) from 160 to 230 mmol·L^(-1) at 0 mmol·L^(-1) NaCl because of the steric hindrance caused by the alginate-grafting layer.Effects of ionic strength(IS) indicated that the adsorption capacities of the resins with the IC value of 230-370 mmol·L^(-1) were much higher than CM Sepharose FF at 50-100 mmol·L^(-1) NaCl,and the uptake rate of Alg-FF-230 was about twice as much as that of CM Sepharose FF.This work demonstrated the important effects of alginate-grafting layer and IS in γ-globulin adsorption behavior,which would be helpful in the design of Alggrafted resins and the selection of proper IS condition for protein purification.

Modelling and experimental investigation of effects of moisture and operating parameters during the adsorption of CO2 onto polyaspartamide

Parametric effect of moisture and influence of operating variables on the adsorption behaviour of polyaspartamide during CO2 capture was investigated in this study using experimental and modelling approach. Individual effects of operating conditions (e.g. pressure, temperature and gas flow rates) as well as the effect of moisture on the adsorption capacity of polyaspartamide were methodically investigated using Dubinin-Raduskevich model. Results from the investigations reveal that the presence of moisture in the flue gas had an incremental effect on the adsorption capacity of polyaspartamide;thereby showcasing the potential of polyaspartamide as a suitable hydrophilic material for CO2 capture in power plants. In addition, pressure, temperature and gas flow rates at 200 kPa, 403 K, and 1.5 mL/s, respectively, sig? nificantly influenced the CO2 adsorption capacity of polyaspartamide. Physisorption and chemisorption both governed the adsorption process while equilibrium studies at different temperatures showed that Langmuir isotherm could adequately describe the adsorption behaviour of the material with best fit with R^2>0.95.

An Adsorption Kinetic Model for Sulfur Dioxide Adsorption by ZL50 Activated Carbon

A semi-empirical adsorption kinetic model was proposed with the time compensation method to describe the chemisorption of SO2 in flue gas by carbon adsorbents for flue gas purification.The change in adsorption capacity and adsorption rate with time at different water vapor concentrations and different SO2 concentrations was studied.The model was in good agreement with experimental data.The surface reaction was probably the rate controlling step in the early stage for SO2 adsorption by ZL50 activated carbon.The parameters m and n in the nth order adsorption kinetic model were related to the magnitude of the time compensation and adsorption driving force,respectively.The change of parameter n with water vapor concentrations and sulfur dioxide concentrations was studied and some physical implications were given.The sum of square errors was less than 1.0 and the average absolute percentage deviations ranged from 0.5 to 3.2.The kinetic model was compared with other models in the literature.

Effects of Pre-oxidation Conditions on Adsorption Performance of Activated Carbon Fibers

In order to investigate the effects of pre-oxidation conditions on adsorption performance of activated carbon fibers ( ACFs) ,electrospun polyacrylonitrile ( PAN) fiber webs were adopted as precursors for preparing ACFs. Firstly,the webs were stabilized under different pre-oxidation conditions; secondly,the pre-oxidative fibers were chemically activated by high temperature treatment in nitrogen. Pre-oxidation temperature,heating rate,and treatment time are the main factors on affecting the adsorption performance of the ACFs. Scanning electron microscope ( SEM) , differential scanning calorimeter ( DSC ) ,and Fourier transform infrared spectroscopy ( FTIR ) were used to characterize the structure and property of the pre-oxidative fibers,and the dynamic benzene adsorption capacity of benzene of ACFs was measured. The results indicate that the moderate pre-oxidation condition is necessary to prepare the ACFs with better adsorption capacity,and the optimal oxidation conditions are to increase from room temperature to 230 ℃ with a heating rate of 0. 75 ℃·min - 1 ,held at the peak temperature for 30 min.

Study on the adsorption of Cr( Ⅵ) onto landfill liners containing granular activated carbon or bentonite activated by acid

The adsorption capacity of landfill liners containing granular activated carbon (GAC), or bentonite activated by acid, for Cr(VI) was investigated by batch testing. The results show that both GAC and activated bentonite could be used as sorptive amendments for trapping Cr(VI) in landfill liners. The Cr(VI) sorption to GAC and activated bentonite is much greater than Cr(VI) sorption to natural clay. The adsorption capacity of Cr(VI) onto all the soils increases with increasing temperature; adsorption capacity is also significantly influenced by soil-solid concentration. As the soil-solid concentration increases the adsorption capacity first decreases logarithmically, but then stabilizes when the soil-solid concentration exceeds a critical value (e.g. 400 g/L). Permeability tests were conducted in the laboratory. The results indicate that the hydraulic conductivity of landfill liners containing GAC or activated bentonite can meet the engineering requirement of 1 nm/s. One-dimensional transport simulations for Cr(VI) were performed to evaluate the effect of GAC and activated bentonite on landfill liners. The results of the simulations indicate that landfill liners containing GAC, or activated bentonite, significantly retard the transport of Cr(VI) relative to a conventional clay liner.

Adsorption of Ammonium and Heavy Metal Ions on Industrial Vermiculite from the Yuli Mine in Xinjiang, China

The present work discusses the mineralogy, saturated adsorption of ammonium and adsorption of heavy metal ions （Cu^2＋, Pb^2＋ and Zn^2＋） on industrial vermiculite samples from the Yuli Mine in Xinjiang Autonomous Region. The saturated adsorption capacity of ammonium and the affection factors of adsorption of Cu^2＋, Pb^2＋ and Zn^2＋ are discussed on the basis of the mineralogical characteristics of the industrial vermiculite samples. The saturated adsorption capacities of ammonium are between 56.02 and 98.42 mmol/100g. The time of adsorption equilibrium is about 30-60 min, and the pH values and concentration of the ion solution significantly affect the adsorption capacities of the heavy metal ions. The adsorption capabilities of the heavy metal ions on industrial vermiculite are almost the same in the low ion concentration solutions, characterized by a sequence of Zn^2＋〉Pb^2＋〉Cu^2＋ for adsorption capacity in solutions with relatively high ion concentration. The results have practical significance for the application of the industrial vermiculite to treating wastewater containing ammonium or heavy metal ions.

Adsorption Properties and Cost of Dicarboxylic Nanocellulose on Copper Ions for Wastewater Treatment

The accumulation of Cu^(2+)in water is a potential threat to human health and environment.Dicarboxylic nano-cellulose(DNC)with rich carboxyl groups was prepared through the NaIO_(4)–NaClO_(2) sequential oxidation meth-od to efficiently remove copper ions,and the Cu 2+adsorption properties and cost were studied.The maximum adsorption capacity reached 184.2 mg/g at pH 6 and an adsorbent dose of 5 g/L.Theoretically,the maximum adsorption capacities of monocarboxylic nanocellulose(MNC),DNC,and tricarboxylic nanocellulose(TNC)with carboxyl groups as the main adsorption sites were calculated to be 228.7,261.3,and 148.1 mg/g,respectively.The Cu^(2+)adsorption costs of MNC,DNC,and TNC were calculated and compared with those of powdered activated carbon(PAC).The Cu^(2+)adsorption capacity of DNC is higher than that of PAC,and the adsorption cost is close to or lower than that of PAC,demonstrating that the DNC prepared by sequential oxidation of NaIO_(4)–NaClO_(2) has competitive adsorption capacity and cost in the treatment of wastewater containing Cu^(2+).

Capacity Titration Technique for Determining the Solid Diffusion Coefficient of Intercalary Species within Insertion-host Materials

In this paper, the capacity titration technique （CT technique） was developed on basis of the RPG （ratio of potentio-charge capacity to galvano-charge capacity） method to continuously determine the solid diffusion coefficient D of the intercalary species within insertion-host materials with a small voltage region. The linear equations of D vs. q （value of ratio of the potentio-charge capacity to the galvano-charge capacity） were given in different range of q. By the CT technique,the Li^＋ solid diffusion coefficients D within LiMn2O4 at different voltages were determined. The results showed that the values of D varied from 3.447×10^-9 cm^2/s to 7.60×10^-11 cm^2/s in the voltage range of charge from 3.3V to 4.3V as a function of voltage with “W” shape.

Adsorption of Pb(II) onto Modified Rice Bran

In this study, the modified rice bran was tested to remove Pb(II) from water. Batch experiments were carried out to evaluate the adsorption characteristics of the modified rice bran for Pb(II) removal from aqueous solutions. The adsorption isotherms, thermodynamic parameters, kinetics, pH effect, and desorbability were examined. The results show that the maximum adsorption capacity of the modified rice bran was approximately 70.8 mg Pb(II)/g absorbent at temperature of 25℃ and at the initial Pb(II) concentration of 400 mg/L and pH 7.0. And the adsorption isotherm data could be well fitted by both Langmuir equation and Freundlich equation. Thermodynamic studies confirmed that the process was spontaneous and endothermic. The adsorbed amounts of Pb(II) tend to increase with the increase of pH. The adsorption kinetic data can be satisfactorily described by either of the power functions and simple Elovich equations. The desorbability of Pb(II) is about 15-20%, and it is relatively difficult for the adsorbed Pb(II) to be desorbed. The relatively low cost and high capabilities of the rice bran make it potentially attractive adsorbent for the removal of Pb(II) from wastewater.

Adsorption and Desorption of Phenol on XDA-1 Macroreticular Resin

The adsorption properties of phenol on XDA-1 resin were studied by chemical analysis and IR spectrometry.The statically saturated adsorption capacity,dynamic saturated adsorption capacity,apparent activation energy,thermodynamic parameters,and adsorption rate constants were measured at different temperatures.As a result,adsorption of phenol on the resin obeys the Freundlich formula.And phenol was recovered quantitatively when ethanol,acetone or 1.0 mol/L sodium hydroxide were used to desorb it from the column.