Analysis of Adsorbed Methane Gas Structure and Mullikan Charges

2014 ◽  
Vol 962-965 ◽  
pp. 1118-1122
Author(s):  
Hua Ping Yang ◽  
Ming Li
Keyword(s):  
Adsorption Process ◽  
Adsorption Equilibrium ◽  
Dft Method ◽  
Model Structure ◽  
Dispersion Forces ◽  
Methane Gas ◽  
Adsorbed Methane ◽  
Molecule Model ◽  
Equilibrium Geometries ◽  
Basic Sets

The methane molecule model, the coal molecule model and the absorption model of coal and methane have been thoroughly investigated using the DFT method,Van der Walls force radius as boundary conditions as well. The investigations focuses on optimizing the three types of model structure. Meanwhile, adsorption equilibrium geometries with 6-311G++ basic sets have been established. Through the model analysis of the changes in the structure and Millikan charge from free state to the adsorption states, the results indicate that the adsorption process of methane gas on the coal in the Van der Walls force mainly dispersion forces and induction force, methane molecules are polarized in the adsorption process, the electric dipole moment.

The Absorption Energy and Equilibrium Structure Analysis of CH4 on Coal Molecules

2013 ◽  
Vol 807-809 ◽  
pp. 2366-2370
Author(s):  
Hua Ping Yang ◽  
Ming Li ◽  
Zheng Xin Yan ◽  
Dong Zhi Yan
Keyword(s):  
Structure Analysis ◽  
Dft Method ◽  
Equilibrium Structure ◽  
Atomic Charges ◽  
Absorption Model ◽  
Absorption Energy ◽  
Molecule Model ◽  
Basic Sets

The coal molecule model and the absorption model of coal and methane were established according to Van der Walls force. The coal molecule model and the absorption model of coal and methane were optimized and obtained absorption energy and equilibrium structure with the DFT method with 6-311G++ basic sets. The effects of coal molecule on the absorption position, absorption energy and absorption distance of CH4 were presented by analyzing the Mulliken atomic charges of coal molecules.

Mercury Removal from Wastewater by Steamed Hoof Powder

1999 ◽  
Vol 40 (7) ◽  
pp. 109-116 ◽  
Author(s):  
M. H. Ansari ◽  
A. M. Deshkar ◽  
P. S. Kelkar ◽  
D. M. Dharmadhikari ◽  
M. Z. Hasan ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Adsorption Capacity ◽  
Adsorption Process ◽  
Adsorption Equilibrium ◽  
Light Metal ◽  
Mercury Removal ◽  
High Adsorption ◽  
Surface Sites ◽  
Ph Values ◽  
High Adsorption Capacity

Steamed Hoof Powder (SHP), size < 53μ, was observed to have high adsorption capacity for Hg(II) with >95% removal from a solution containing 100 mg/L of Hg(II) with only 0.1% (W/V) concentration of SHP. The SHP has good settling properties and gives clear and odour free effluent. Studies indicate that pH values between 2 and 10 have no effect on the adsorption of Hg(II) on SHP. Light metal ions like Na+, K+, Ca2+ and Mg2+ up to concentrations of 500 mg/L and heavy metals like Cu2+, Zn2+, Cd2+, Co2+, Pb2+, Ni2+, Mn2+, Cr3+, Cr6+, Fe2+ and Fe3+ up to concentrations of 100 mg/L do not interfere with the adsorption process. Anions like sulphate, acetate and phosphate up to concentrations of 200 mg/L do not interfere. Chloride interferes in the adsorption process when Hg(II) concentration is above 9.7 mg/L. The adsorption equilibrium was established within two hours. Studies indicate that adsorption occurs on the surface sites of the adsorbent.

A Comprehensive Computational Study on OCH+-Rg (Rg = He, Ne, Ar, Kr, Xe) Complexes

2003 ◽  
Vol 68 (3) ◽  
pp. 489-508 ◽  
Author(s):  
Yinghong Sheng ◽  
Jerzy Leszczynski
Keyword(s):  
Computational Study ◽  
Relativistic Effects ◽  
Dft Method ◽  
Basis Set ◽  
Rare Gas ◽  
Geometrical Parameters ◽  
Minor Effect ◽  
Dissociation Energies ◽  
Equilibrium Geometries

The equilibrium geometries, harmonic vibrational frenquencies, and the dissociation energies of the OCH+-Rg (Rg = He, Ne, Ar, Kr, and Xe) complexes were calculated at the DFT, MP2, MP4, CCSD, and CCSD(T) levels of theory. In the lighter OCH+-Rg (Rg = He, Ne, Ar) rare gas complexes, the DFT and MP4 methods tend to produce longer Rg-H+ distance than the CCSD(T) level value, and the CCSD-calculated Rg-H+ bond lengths are slightly shorter. DFT method is not reliable to study weak interaction in the OCH+-He and OCH+-Ne complexes. A qualitative result can be obtained for OCH+-Ar complex by using the DFT method; however, a higher-level method using a larger basis set is required for the quantitative predictions. For heavier atom (Kr, Xe)-containing complexes, only the CCSD method predicted longer Rg-H+ distance than that obtained at the CCSD(T) level. The DFT method can be applied to obtain the semiquantitative results. The relativistic effects are expected to have minor effect on the geometrical parameters, the H+-C stretching mode, and the dissociation energy. However, the dissociation energies are sensitive to the quality of the basis set. The nature of interaction between the OCH+ ion and Rg atoms was also analyzed in terms of the interaction energy components.

Pseudo-Second-Order Kinetics for the Adsorption of Uranyl Ion onto Peat at Different pH Value

2010 ◽  
Vol 113-116 ◽  
pp. 33-36
Author(s):  
Zhi Rong Liu ◽  
Qin Qin Tao ◽  
Chuan Xi Wen
Keyword(s):  
Contact Time ◽  
Adsorption Process ◽  
Adsorption Equilibrium ◽  
Ph Value ◽  
Second Order ◽  
Uranyl Ions ◽  
Batch Tests ◽  
Effects Of Ph ◽  
Pseudo Second Order

Batch tests were used to investigate the effects of pH and contact time on the adsorption capability of peat. The results indicate that adsorption of uranyl ions on peat increase with increasing pH from 1 to 5. However it takes longer contact time to reach the adsorption equilibrium with increase of pH from 1 to 5. The adsorption process can be described by type 1 of the pseudo-second-order kinetics excellently.

Adsorption of Phenol on Natural Sediment from Liaohe River, China

2011 ◽  
Vol 356-360 ◽  
pp. 252-258
Author(s):  
Ying Zhang ◽  
Jian Xu ◽  
Yuan Zhang ◽  
Lei Li ◽  
Jiang Ying Zhang
Keyword(s):  
Ionic Strength ◽  
River Sediment ◽  
Adsorption Process ◽  
Adsorption Equilibrium ◽  
Intraparticle Diffusion ◽  
Natural Sediment ◽  
Phenol Adsorption ◽  
Intraparticle Diffusion Model ◽  
Liaohe River ◽  
Ph Dependent

In this study, the adsorption behavior of phenol onto natural sediments from Liaohe River was studied. The effect of pH, temperature, ionic strength, and surfactants on the adsorption process was also investigated. Results showed that it took 48 h for the phenol to achieve adsorption equilibrium on sediment. Kinetic analysis indicated that the process fit well with the intraparticle diffusion model. The phenol adsorption process was pH dependent with the maximum adsorption at pH 4.58. With respect to the Freundlich and Langmuir models, the DR isotherm can describe the adsorption process better. Thermodynamic parameters revealed that phenol adsorption was physisorption. The coexistent salt and surfactants at relatively higher concentrations inhibited the phenol adsorption on Liaohe River sediment.

Thermodynamics of Cr(VI) Adsorption on Thiourea Chelating Ion Exchange Fiber

2014 ◽  
Vol 894 ◽  
pp. 121-124 ◽  
Author(s):  
Yan Qiang Jian ◽  
Ming Yu Li ◽  
Qing Xuan Zeng
Keyword(s):  
Ion Exchange ◽  
Adsorption Process ◽  
Adsorption Equilibrium ◽  
Polypropylene Fiber ◽  
Equation Model ◽  
Batch Adsorption ◽  
Equilibrium Data ◽  
Endothermic Process ◽  
Adsorption Equilibrium Data ◽  
Ion Exchange Fiber

A chelating ion exchange fiber containing thioureido groups for the removal of Cr (VI) has been prepared from chloramethylated styrene grafted polypropylene fiber (2.96 mmol/g Cl) reacted with thiourea, batch adsorption experiments are adopted to investigate its adsorption equilibrium properties, Adsorption isotherms at various temperatures were obtained. Langmuir linear equation model can well describe the adsorption equilibrium data suggesting that the adsorption process involves both chemisorption and physisorption. The values of thermodynamic parameters, including ΔH, ΔGand ΔS, indicate that the adsorption of Cr (VI) is a spontaneous, entropy-driven and endothermic process.

Adsorption and recovery of nonylphenol ethoxylate on a crosslinked β-cyclodextrin-carboxymethylcellulose polymer

2010 ◽  
Vol 61 (9) ◽  
pp. 2293-2301 ◽  
Author(s):  
Danielle Bonenfant ◽  
Patrick Niquette ◽  
Murielle Mimeault ◽  
Robert Hausler
Keyword(s):  
Adsorption Capacity ◽  
Atmospheric Pressure ◽  
Active Sites ◽  
Adsorption Process ◽  
Adsorption Equilibrium ◽  
Physical Adsorption ◽  
Polymer Network ◽  
Homogeneous Distribution ◽  
Nonylphenol Ethoxylate ◽  
Monolayer Coverage

A study of adsorption/recovery of nonylphenol 9 mole ethoxylate (NP9EO) on a crosslinked β-cyclodextrin-carboxymethylcellulose (β-CD-CMC) polymer was carried out by ultraviolet-visible (UV-vis) and Fourier transform infrared (FTIR) spectroscopies. The adsorption was performed in mixtures containing 500 mg of the β-CD-CMC polymer and aqueous NP9EO solutions at concentrations 12–82 mg/L, whereas the recovery of NP9EO was effectuated by shaking the β-CD-CMC polymer loaded with methanol. The assays were made at 25°C and atmospheric pressure under agitation. The results have shown that the adsorption is a rapid process and the β-CD-CMC polymer exhibits a high NP9EO adsorption capacity of 83–92 w% (1.1–6.8 mg NP9EO/g β-CD-CMC polymer) dependent of the initial NP9EO concentration in liquid phase. This adsorption may involve the formation of an inclusion complex β-CD-NP9EO and a physical adsorption in the polymer network. The adsorption equilibrium measurements, which were analyzed using the Langmuir isotherm, have indicated a monolayer coverage and the homogeneous distribution of active sites at the surface of the β-CD-CMC polymer. Moreover, the negative value obtained for the free energy change (−13.2 kJ/mol) has indicated that the adsorption process is spontaneous. In parallel, the β-CD-CMC polymer exhibited a high NP9EO recovery efficiency of 97 w% that may occur through a decrease of binding strength between β-CD-CMC polymer and NP9EO. Together, these results suggest that the β-CD-CMC polymer could constitute a good adsorbent for removing nonylphenol ethoxylates from wastewater due to its high adsorption capacity and non-toxic character of β-CD and CMC to environment.

scholarly journals Equilibrium and Kinetic study of lead and copper ions adsorption on Chitosan-grafted-poly acrylic acid synthesized by Surface-initiated Atomic Transfer Polymerization

2018 ◽  
Author(s):  
Carlos Grande ◽  
William Vallejo ◽  
Fabio Zuluaga
Keyword(s):  
Acrylic Acid ◽  
Adsorption Process ◽  
Adsorption Equilibrium ◽  
Copper Ions ◽  
Surface Adsorption ◽  
Toxic Metal ◽  
Maximum Adsorption Capacity ◽  
Equilibrium Studies ◽  
Adsorption Capacities ◽  
Poly Acrylic Acid

In this work, we synthesized chitosan grafted-poly acrylic acid (CS-g-PA) through surface-initiated atom transfer radical polymerization (SI-ATRP). We also studied the adsorption process of copper and lead ions onto CS-g-PA surface. Adsorption equilibrium studies indicated pH 4.0 as the best pH for the adsorption process, while the maximum adsorption capacity for Pb2+ ions was 98 mg*g-1 and for Cu2+ was 164 mg*g-1, higher adsorption capacities than chitosan alone (CS), where Pb2+ was only 14.8 mg*g-1and Cu2+ was 140 mg*g-1, respectively. Furthermore, the adsorption studies indicated that Langmuir model describes all the experimental data. All these results suggest that the new CS-g-PA polymers had potential as adsorbent for hazardous and toxic metal ions produced by different industries.

scholarly journals Oyster Shell Waste (Crassostrea Gigas) as A Cheap Adsorbent for Adsorption Of Methylene Blue Dyes: Equilibrium and Kinetics Studies

2021 ◽  
Vol 1 (4) ◽  
pp. 95-102
Author(s):  
Muhammad Muhammad ◽  
Meriatna Meriatna ◽  
Nia Afriani ◽  
Rizka Mulyawan
Keyword(s):  
Methylene Blue ◽  
Correlation Coefficient ◽  
Crassostrea Gigas ◽  
Adsorption Process ◽  
Adsorption Equilibrium ◽  
Oyster Shell ◽  
Second Order ◽  
Order Model ◽  
Pseudo Second Order ◽  
Shell Powder

In this study, Oyster (Crassostrea gigas) shell powder which contains calcium carbonate (CaCO3) was converted into calcium oxide (CaO). The Oyster shell powder that had been activated was utilized for the adsorption of the methylene blue (MB) dyeing material, which is one of waste water concerns. Oyster shells were crushed and sieved into 100 mesh sized powder and then calcinated at a temperature of 600℃ and 800℃ both for 4 hours period. To determine the adsorption equilibrium, methylene blue (MB) solution was used with varying concentration from 10 to 50 mg/L in which the adsorbent weighing 3 g was put into a conical flash and shaken until the adsorption equilibrium was reached. As for the adsorption kinetics, 250 mL MB solution was used with initial concentrations of 10, 20 and 30 mg/L, with an adsorbent weight of 3 g and a solution at pH 11 for each concentration. The evaluation of the experimental data from the adsorption process is well explained by the Freundlich equation, with the correlation coefficient value (R2) found to be 0.9999, where the value of the adsorption intensity (n) is close to unity; this shows that the adsorption is multilayer or in other words the adsorption energy is heterogeneous. The kinetics study also shows that pseudo second-order model is the most applicable to the adsorption process. From the pseudo-second-order model, with the correlation coefficient between 0.9984 - 0.9999 can explain that the methylene blue (MB) adsorption process is chemically based sorption or in other words termed as chemisorption.

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