Influence of MgO loading on the structure and catalytic performance of Pd/γ-Al2O3, part 2. Competitive adsorption properties of palladium cations on MgO/γ-Al2O3

1996 ◽  
Vol 59 (2) ◽  
pp. 375-380
Author(s):  
Caixia Qi ◽  
Tingfang Bai ◽  
Lidun An
Keyword(s):  
Competitive Adsorption ◽  
Catalytic Performance ◽  
Adsorption Properties

scholarly journals Interconnected Micro, Meso, and Macro Porous Activated Carbon from Bacterial Nanocellulose for Superior Adsorption Properties and Effective Catalytic Performance

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4063
Author(s):  
Arnon Khamkeaw ◽  
Tatdanai Asavamongkolkul ◽  
Tianpichet Perngyai ◽  
Bunjerd Jongsomjit ◽  
Muenduen Phisalaphong
Keyword(s):  
Activated Carbon ◽  
Reaction Temperature ◽  
Mass Transfer Rate ◽  
Catalyst Support ◽  
Catalytic Performance ◽  
Adsorption Properties ◽  
Bet Surface Area ◽  
Ethanol Conversion ◽  
Bacterial Nanocellulose ◽  
Effective Performance

The porous carbon (bacterial cellulose (BC)-activated carbon (AC)(BA)) prepared via two-step activation of bacterial nanocellulose by treatments with potassium hydroxide (KOH) and then phosphoric acid (H3PO4) solutions showed superior adsorption properties and effective performance as catalyst support. BC-AC(BA) had an open and interconnected multi-porous structure, consisting of micropores (0.23 cm3/g), mesopores (0.26 cm3/g), and macropores (4.40 cm3/g). The BET surface area and porosity were 833 m2/g and 91.2%, respectively. The methylene blue adsorption test demonstrated that BC-AC(BA) was superior in its mass transfer rate and adsorption capacities. Moreover, BC-AC(BA) modified by H3PO4 treatment showed a significant enhancement of catalytic performance for dehydration of ethanol. At the reaction temperature of 250–400 °C, 30P/BC-AC(BA) gave ethanol conversion at 88.4–100%, with ethylene selectivity of 82.6–100%, whereas, high selectivity for diethyl ether (DEE) at 75.2%, at ethanol conversion of 60.1%, was obtained at the reaction temperature of 200 °C.

Adsorption properties of CH4 and CO2 in quartz nanopores studied by molecular simulation

RSC Advances ◽  
2016 ◽  
Vol 6 (39) ◽  
pp. 32770-32778 ◽  
Author(s):  
Haoyang Sun ◽  
Wenchao Sun ◽  
Hui Zhao ◽  
Yange Sun ◽  
Dianrui Zhang ◽  
...  
Keyword(s):  
Molecular Simulation ◽  
Binary Mixtures ◽  
Adsorption Isotherms ◽  
Competitive Adsorption ◽  
Adsorption Properties ◽  
Density Distributions ◽  
Adsorption Density ◽  
Surface Hydroxylation

Competitive adsorption isotherms and adsorption density distributions of binary mixtures containing CH4 and CO2 in nanopores with 100% and 60% surface hydroxylation at 323 K.

DFT insights into the adsorption of NH3-SCR related small gases in Mn-MOF-74

2016 ◽  
Vol 18 (41) ◽  
pp. 28854-28863 ◽  
Author(s):  
Minhua Zhang ◽  
Xuewei Huang ◽  
Yifei Chen
Keyword(s):  
Competitive Adsorption ◽  
Adsorption Properties ◽  
Nh3 Scr

The adsorption properties of six NH3-SCR related small gases and the competitive adsorption of NH3, SO2 and NH3, H2O were investigated.

scholarly journals Bridging Adsorption Analytics and Catalytic Kinetics for Metal-Exchanged Zeolites

2020 ◽  
Author(s):  
Pengfei Xie ◽  
Tiancheng Pu ◽  
Gregory Aranovich ◽  
Jiawei Guo ◽  
Marc Donohue ◽  
...  
Keyword(s):  
Low Temperature ◽  
Active Sites ◽  
Molecular Spectroscopy ◽  
Catalytic Performance ◽  
Quantitative Information ◽  
Adsorption Properties ◽  
Structure Property ◽  
Atomic Structures ◽  
Structure Property Relationships ◽  
High Temperature Reaction

Abstract Metal-exchanged zeolites have been widely used in industrial catalysis and separation, but fundamental understanding of their structure-property relationships has remained challenging, largely due to the lack of quantitative information concerning the atomic structures and reaction-relevant adsorption properties of the embedded metal active sites. We report on the use of low-temperature chemisorption to titrate Cu-exchanged ZSM5. Quantitative descriptors of the atomic structures and adsorption properties of Cu-ZSM5 are established by combining atomistic simulation, DFT calculations, operando molecular spectroscopy, chemisorption and titration measurements. These descriptors are then applied to interpret the catalytic performance of Cu-ZSM5 for NO decomposition. Linear correlations are established to bridge the low-temperature adsorption analytics and high-temperature reaction kinetics, which are demonstrated to be generally applicable for understanding the structure-property relationships of metal exchanged zeolites and foregrounded for guiding the development of advanced catalytic materials.

Effect of Competitive Adsorbates on the Catalytic Activity of H3PMo12O40@C in the Oxidation of NMST to NMSBA

2020 ◽  
Vol 18 (3) ◽  
Author(s):  
Hua-jie Liu ◽  
Zhou-wen Fang ◽  
Xin-zhi Zhou ◽  
Xiang-li Long
Keyword(s):  
Acetic Acid ◽  
Catalytic Activity ◽  
Competitive Adsorption ◽  
Phosphomolybdic Acid ◽  
Catalytic Performance ◽  
Good Dispersion ◽  
Tem Characterization ◽  
Negative Effect ◽  
Impregnation Solution

AbstractThe effect of competitive adsorption on the catalytic performance of H3PMo12O40@C catalyst for producing 2-nitro-4-methylsulfonylbenzoic acid (NMSBA) from the oxidation of 2-nitro-4- methylsulfonyltoluene (NMST) by oxygen in acetic acid has been investigated. Six kinds of acids were added into the impregnation solution as competitive adsorbates for phosphomolybdic acid in the preparation of H3PMo12O40@C catalyst. H2SO4, HCl, HNO3, CH3COOH and H2C2O4 are beneficial to improving the catalytic activity of the H3PMo12O40@C catalyst. The corresponding optimum impregnation concentrations for H2SO4, HCl, HNO3, CH3COOH and H2C2O4 are 0.4, 0.3, 0.3, 1.0 and 0.3 mol L−1, respectively. The addition of H3PO4 exerts a negative effect on the catalytic capability of H3PMo12O40@C catalyst. The results of TEM characterization show that good dispersion of H3PMo12O40 on the surface of the H3PMo12O40@C catalyst is beneficial to ameliorating the catalytic ability of H3PMo12O40@C catalyst in the production of NMSBA from NMST by oxygen in acetic acid. The results of NH3-TPD indicate that the acidity of the H3PMo12O40@C also favors the improvement of the catalytic capability of H3PMo12O40@C in the oxidation of NMST to NMSBA.

The removal of Cu(II) and Pb(II) ions from aqueous solutions by temperature-sensitive hydrogels based on N-isopropylacrylamide and itaconic acid

2021 ◽  
pp. 1-19
Author(s):  
Bengi Özkahraman ◽  
Eren Yıldırım ◽  
Serkan Emik ◽  
Işıl Acar
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Kinetics ◽  
Itaconic Acid ◽  
Competitive Adsorption ◽  
Adsorption Properties ◽  
Temperature Sensitive ◽  
Order Model ◽  
Ion Removal ◽  
Adsorption Capacities ◽  
Pseudo Second Order

This study deals with the potential use of poly(N-isopropylacrylamide-co-itaconic acid) temperature-sensitive hydrogels as an adsorbent for the removal of Cu(II) and Pb(II) ions from aqueous solutions. For this aim, the adsorption properties of hydrogels were examined by adsorption capacities, adsorption isotherm, and adsorption kinetics experiments. To describe the adsorption characteristics of hydrogels, the obtained experimental data were evaluated by Langmuir, Freundlich, Redlich-Peterson, and Dubinin-Radushkevich isotherm models. Adsorption kinetics experiments were carried out not only in single systems but also in binary systems where both ions were at equal initial concentrations for competitive adsorption studies. To predict the behaviors of the competitive and non-competitive adsorption process of ions onto hydrogels, the experimental adsorption data were analyzed by the pseudo-first-order model and the pseudo-second-order model. According to non-competitive ion removal findings, the adsorption capacities followed order Cu(II) >  Pb(II) for all hydrogels, and the pseudo-second-order kinetic model explained the adsorption properties of the hydrogels. Competitive ion removal studies showed that all hydrogels were selective to Cu(II) ion. Furthermore, in the case of comparative investigations both of competitive Cu(II) and competitive Pb(II) removal by hydrogels, the metal ion removal capacity of N10 hydrogel was found as a bit higher than that of N7.5 and N5 in 48 h. That is, as the acidic group content increased in the hydrogel network, the adsorption capacity values also increased. In addition, the reusability of temperature-sensitive hydrogels seems possible without regeneration or after regenerating with acid, in case the temperature is increased above the LCST. Furthermore, even if it cannot be reused, these hydrogels that retain metal ions reach very small volumes by shrinking when the LSCT is exceeded, and thus they can be eliminated more easily than other conventional gels due to their small size. As a result, this temperature-sensitive hydrogel may propose as an alternative environmentally friendly adsorbent candidate for can be used for water purification and wastewater treatment.

scholarly journals Boosting the Catalytic Performance of Co/Mg/La Catalyst for Ammonia Synthesis by Selecting a Pre-Treatment Method

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 941
Author(s):  
Hubert Ronduda ◽  
Magdalena Zybert ◽  
Wojciech Patkowski ◽  
Andrzej Ostrowski ◽  
Przemysław Jodłowski ◽  
...  
Keyword(s):  
Ammonia Synthesis ◽  
Treatment Method ◽  
Catalytic Performance ◽  
Adsorption Properties ◽  
Detailed Characterization ◽  
Calcination Process ◽  
Catalytic Behavior ◽  
Characterization Methods ◽  
Pre Treatment ◽  
Catalytic Performances

The influence of the calcination process on the physicochemical properties and catalytic behavior of the Co/Mg/La catalysts for ammonia synthesis has been investigated. The catalysts were prepared using the different thermal pre-treatment methods prior to the activation, i.e., drying and calcination, and the respective activities for ammonia synthesis were assessed. It was found out that changing from air calcination prior to activation to direct activation of the co-precipitated species led to the different catalytic performances. The most favorable catalytic performance was achieved with Co/Mg/La prepared by calcination in air. Detailed characterization methods, employing e.g., XRPD, H2-TPD, N2-TPD, CO2-TPD, SEM, and TEM, showed that the superior catalytic behavior of this catalyst was attributed to its strong basicity and favorable adsorption properties toward hydrogen and nitrogen.

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