Papers by Keyword: Chemisorption

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Authors: Rika Wulandari, Jumina, Dwi Siswanta
Abstract: The adsorption of Remazol by CEMPCRP was studied as a function of pH, contact time and concentration. All experiments were carried out using the batch method. The initial and final RBBR concentration were determinated using UV-Vis spectrometer at λ = 592.3 nm. The result showed that the optimum condition of RBBR adsorption were at pH 10, contact time 360 min, and concentration of 300 mg/L. This adsorption followed the Lagergren (first pseudo order) and Langmuir isotherm adsorption model. The adsorption capacity was obtained 6.51 x 10-5 mol/L and the mechanism is a chemisorption (ΔG = 28.92 kJ/mol) that occurs in the monolayer.
Authors: M.A. Olutoye, F. Aberuagba, J.O. Odigure
Authors: Arturo I. Martinez
Abstract: Density functional theory calculations of hydrogen storage capacity for different organometallic structures have been carried out. Complexes involving Sc, Ti and V bound to C4H4, C5H5, C5F5 and B3N3H6 molecules have been considered, and all present a hydrogen storage capability limited by the 18-electron rule. In order to stabilize the complexes, which the 18-electron rule is not completed, additional ligands are considered, namely -H, -CH3, -NH2, -OH and -F. These ligands affect the H2-metal bond; particularly the back donation effect from the metal atom to the * antibonding state of H2 and then its H2 storage capacity.
Authors: Ji Qiao Zhang, Gan Yun Huang, Xi Qiao Feng, Shou Wen Yu
Abstract: An energy-based model is presented to predict the deflection and resonance frequency shift of a microcantilever induced by chemisorption. The chemisorption of oxygen on Si(100) surface is taken as a representative example. The connection between the continuum-level cantilever responses (e.g. static deflection, resonance frequency) and the molecular-level interactions (covalent bond interactions) are established. The mechanical behavior of the cantilever on the density of adsorbed atoms/molecules and the property of the substrate is investigated. This study is helpful for designing microcantilever-based sensors which have many technologically important applications
Authors: Zheng Hao Fei, Wei Zhong Shi, Zhong Tang Liu, Jian Chen, Rong Xing, Yun Lan Gu, Gen Cheng Zhang
Abstract: Functional groups modified into adsorption resins were designed based on semiempirical molecular orbital theory, and the newly adsorption resin (named FZH01 modified with phthalic anhydride) having both the lower LUMO level and the higher HOMO level was prepared. The static adsorption and static desorption characteristics for gallic acid in aqueous solution onto FZH01, NDA150 and GAC at the temperature range of 288~318K were studied with bottle point method to confirm the existence of chemisorption between adsorbate and adsorbents modified, which was interpreted by the approximate orbital energy level of several adsorbents and gallic acid calculated with the semiempirical molecular orbital method PM3. The result shows that chemical interaction will be in existence in the adsorption system of gallic acid in aqueous solutions with FZH01 as like that of GAC at the proper temperature. The adsorption capacities of gallic acid in aqueous solutions with the adsorption resins modified with 2-carboxylbenzoyl increase greatly and mechanism for adsorbing gallic acid in aqueous solution was investigated.
Authors: D. Mostefa, B. Fortin, F. Raoult, M. Sarret, G. Rossé, O. Bonnaud
Authors: Ru Song Li, Bin He, Peng Xu, Feng Tao Zhao
Abstract: Chemisorption of CO molecule on the (001) surface of δ-Pu using the generalized gradient approximation of the density functional theory with the Perdew-Burke-Ernzerhof exchange-correlation functional has been investigated without spin-orbit coupling at the non-spin-polarized level to better understand the interaction and chemical reaction of CO with Pu surface. Band structure and density of states before and after CO molecule chemisorption on the bridge position of the (001) surface have been compared and analyzed. The result shows that s and p states of CO molecule hybrid with Pu 6d states. Chemisorption energy for this adsorption site and repulsion energy between CO molecules are 0.615046eV and 0.96768eV, respectively.Key words: density functional;chemisorption;energy band;density of states;repulsion energy
Authors: A. Catellani, G. Cicero, M.C. Righi, C.A. Pignedoli
Abstract: We review some recent investigations on prototypical SiC-based interfaces, as obtained from first-principles molecular dynamics. We discuss the interface with vacuum, and the role played by surface reconstruction in SiC homoepitaxy, and adatom diffusion. Then we move to the description of a buried, highly mismatched semiconductor interface, the one which occurs between SiC and Si, its natural substrate for growth: in this case, the mechanism governing the creation of a network of dislocations at the SiC/Si interface is presented, along with a microscopic description of the dislocation core. Finally, we describe a template solid/liquid interface, water on SiC: based on the predicted structure of SiC surfaces covered with water molecules, we propose (i) a way of nanopatterning cubic SiC(001) for the attachment of biomolecules and (ii) experiments to reveal the local geometry of adsorbed water.
Authors: Patcharin Racho, Kusuma Namseethan
Abstract: This is a preliminary study for hardness removal via modified starch combined with an ultrafiltration process that provides on high effluence quality and low cost, footprint and environmental impact treatment. This studied on potential of chemisorption process using modified starch as absorbents for hardness removal. Four modified tapioca starches were selected for evaluation that includes of oxidize starch, di-starch phosphate, hydroxyphophyl starch and phosphate monoester as well as non-modified tapioca starch too. Phosphate monoester starch achieved the highest efficiency about 98.2% of hardness removal within the adsorption capacity about 18 mg-hardness removed/g-starch. The modified starch had capable to reduced total hardness from 350.5 mg/L as CaCO3 to 6.3 mg/L as CaCO3 from water. However, the modified starch is an organic matter its can be contaminates in water. Then, a coagulation-flocculation processes were applied for starch colloidal destabilization and flocs by aluminum chloride (PAC) and cationic polymer for starch separation. After that process, turbidity was less than 1 NTU in the effluents. However, the total dissolved solids were increased that may be cause of some starch was solutes. These should be having a future treatment for particulate removal and cutoff the soluble starch in water likes an ultrafiltration process.
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