scholarly journals CO2 Adsorption on Modified Mesoporous Silicas: The Role of the Adsorption Sites

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2831
Author(s):  
Martin Ravutsov ◽  
Yavor Mitrev ◽  
Pavletta Shestakova ◽  
Hristina Lazarova ◽  
Svilen Simeonov ◽  
...  
Keyword(s):  
Co2 Adsorption ◽  
Structural Characteristics ◽  
Absorption Capacity ◽  
Mesoporous Silicas ◽  
Co2 Absorption ◽  
Adsorption Sites ◽  
Synthesis Procedure ◽  
Post Synthesis ◽  
Adsorption Desorption

The post-synthesis procedure for cyclic amine (morpholine and 1-methylpiperazine) modified mesoporous MCM-48 and SBA-15 silicas was developed. The procedure for preparation of the modified mesoporous materials does not affect the structural characteristics of the initial mesoporous silicas strongly. The initial and modified materials were characterized by XRD, N2 physisorption, thermal analysis, and solid-state NMR. The CO2 adsorption of the obtained materials was tested under dynamic and equilibrium conditions. The NMR data revealed the formation of different CO2 adsorbed forms. The materials exhibited high CO2 absorption capacity lying above the benchmark value of 2 mmol/g and stretching out to the outstanding 4.4 mmol/g in the case of 1-methylpiperazin modified MCM-48. The materials are reusable, and their CO2 adsorption capacities are slightly lower in three adsorption/desorption cycles.

scholarly journals Investigation of adsorption/desorption performance by aminopropyltriethoxysilane grafted onto different mesoporous silica for post-combustion CO2 capture

Clean Energy ◽  
2020 ◽  
Vol 4 (2) ◽  
pp. 120-131 ◽  
Author(s):  
Pailin Muchan ◽  
Chintana Saiwan ◽  
Manit Nithitanakul
Keyword(s):  
Adsorption Capacity ◽  
Flow Rate ◽  
Co2 Adsorption ◽  
Hexagonal Structure ◽  
Mesoporous Silicas ◽  
High Rate ◽  
Desorption Process ◽  
Carbon Dioxide Co2 ◽  
Adsorption Desorption ◽  
Interconnected Pore

Abstract Mesoporous silicas with hexagonal structure (MCM-41 and SBA-15) and cubical interconnected pore structure (KIT-6) were synthesized and modified with aminopropyltriethoxysilane (APTES) for using as adsorbents in carbon-dioxide (CO2)-adsorption application. The CO2-adsorption experiment was carried out at room temperature and atmospheric pressure using 15% CO2 with a flow rate of 20 mL/min and the desorption experiment was carried out at 100°C under N2 balance with a flow rate of 20 mL/min. The adsorption capacity and adsorption rate of all modified mesoporous silicas were enhanced due to the presence of primary amine in the structure, which was able to form a fast chemical reaction with CO2. All adsorbents showed good adsorption performance stability after using over five adsorption/desorption cycles. Due to the effect of the adsorbents’ porous structure on the adsorption/desorption process, an adsorbent with sufficient pore-size diameter and pore volume together with interconnected pore, KIT-6, represents a promising adsorbent that gave the optimum adsorption/desorption performance among others. It showed reasonable adsorption capacity with a high rate of adsorption. In addition, it could also be regenerated with 99.72% efficiency using 12.07 kJ/mmolCO2 of heat duty for regeneration.

scholarly journals Basicity determination of SBA-15 doped with different alkaline metals through CO2 adsorption and isopropanol decomposition

2020 ◽  
Vol 11 (2) ◽  
pp. 100-104
Author(s):  
Natalia Romina Reale ◽  
Maria Virginia Cagnoli
Keyword(s):  
Co2 Adsorption ◽  
Structural Characteristics ◽  
Textural Properties ◽  
Light Olefins ◽  
X Ray Diffraction ◽  
Alkaline Metals ◽  
Co2 Desorption ◽  
Isopropanol Decomposition

In order to increase the activity and selectivity towards to light olefins in the Fischer-Tropsch synthesis, new support for the role of iron (Fe) are presented. Thus, SBA-15 was synthetized and doped with different alkaline metals preserving the structural characteristics of the mesoporous solid. The samples were characterized by X-ray diffraction at low angles, N2 adsorption, atomic absorption spectroscopy, CO2 desorption at programmed temperature and isopropanol test. The alkaline metals (Li, K and Cs) introduction into the channels of the solid, generate basic sites of different strength that are not present in the SBA-15 without doping and do not produce significant changes in the structural and textural properties of the SBA-15, only a densification in the walls of the channels is evidenced. According to the alkaline metal used and through CO2 adsorption and isopropanol decomposition, it was possible to established the order by the total number of sites: Li >> K » Cs, and the force order for both types of sites (weak and intermediate): Li > Cs > K.

scholarly journals Cu(II) Ion Adsorption by Aniline Grafted Chitosan and Its Responsive Fluorescence Properties

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1052 ◽  
Author(s):  
Bahareh Vafakish ◽  
Lee D. Wilson
Keyword(s):  
Synergistic Effects ◽  
Fluorescence Emission ◽  
Water Security ◽  
Adsorption Properties ◽  
Metal Species ◽  
Adsorbent Regeneration ◽  
Adsorption Sites ◽  
Adsorption Desorption

The detection and removal of heavy metal species in aquatic environments is of continued interest to address ongoing efforts in water security. This study was focused on the preparation and characterization of aniline grafted chitosan (CS-Ac-An), and evaluation of its adsorption properties with Cu(II) under variable conditions. Materials characterization provides support for the grafting of aniline onto chitosan, where the kinetic and thermodynamic adsorption properties reveal a notably greater uptake (>20-fold) of Cu(II) relative to chitosan, where the adsorption capacity (Qm) of CS-Ac-An was 106.6 mg/g. Adsorbent regeneration was demonstrated over multiple adsorption-desorption cycles with good uptake efficiency. CS-Ac-An has a strong fluorescence emission that undergoes prominent quenching at part per billion levels in aqueous solution. The quenching process displays a linear response over variable Cu(II) concentration (0.05–5 mM) that affords reliable detection of low level Cu(II) levels by an in situ “turn-off” process. The tweezer-like chelation properties of CS-Ac-An with Cu(II) was characterized by complementary spectroscopic methods: IR, NMR, X-ray photoelectron (XPS), and scanning electron microscopy (SEM). The role of synergistic effects are inferred among two types of active adsorption sites: electron rich arene rings and amine groups of chitosan with Cu(II) species to afford a tweezer-like binding modality.

scholarly journals The role of nanotechnology on post-combustion CO2 absorption in process industries

2020 ◽  
Vol 15 (3) ◽  
pp. 361-367
Author(s):  
Ravinder Kumar ◽  
Rajesh Mangalapuri ◽  
Mohammad Hossein Ahmadi ◽  
Dai-Viet N Vo ◽  
Rajniesh Solanki ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Co2 Capture ◽  
Absorption Efficiency ◽  
Absorption Capacity ◽  
Co2 Absorption ◽  
Process Industries ◽  
Ccs Technologies ◽  
And Storage ◽  
Excessive Accumulation

Abstract At present, higher greenhouse gas (GHG) have triggered global efforts to reduce their level as much as possible for sustainable development. Carbon dioxide is one of the imperative anthropogenic emissions due to its increased excessive accumulation in the environment. Thus, serious attention is required to reduce the level of CO2 using advanced and efficient CO2 capture technologies. Carbon dioxide capture and storage (CCS) technologies may play an important role in this direction. At present, solvent-based sorbents are being utilized in CO2 capture for various industrial processes. In this category, the characters of non-materials are playing a crucial role to improve the CO2 absorption capacity of the process. This study is mainly focused on the role of nanotechnology in the post-combustion CO2 absorption process. The functions of nanomaterials and nanoparticles have been studied in the present work. Additionally, various challenges related to absorption efficiency using nanomaterials have been discussed. The study concludes that the higher thermal stability and exceptional properties of nanomaterials popularized them for use in CO2 capture processes.

Role of the Structural Characteristics of Dendrimers in the Manifestation of the Antiamyloid Properties

INEOS OPEN ◽  
2020 ◽  
Vol 3 ◽  
Author(s):  
S. A. Sorokina ◽  
◽  
Yu. Yu. Stroilova ◽  
V. I. Muronets ◽  
Z. B. Shifrina ◽  
...  
Keyword(s):  
Neurodegenerative Diseases ◽  
Structural Characteristics ◽  
Short Review ◽  
External Factors ◽  
Amyloid Aggregation ◽  
Amyloid Proteins ◽  
Molecular Parameters ◽  
Amyloid Aggregates ◽  
Aggregation Processes

Among the compounds able to efficiently inhibit the amyloid aggregation of proteins and decompose the amyloid aggregates that cause neurodegenerative diseases, of particular interest are dendrimers, which represent individual macromolecules with the hypercrosslinked architectures and given molecular parameters. This short review outlines the peculiarities of the antiamyloid activity of dendrimers and discusses the effect of dendrimer structures and external factors on their antiamyloid properties. The potential of application of dendrimers in further investigations on the aggregation processes of amyloid proteins as the compounds that exhibit the remarkable antiamyloid activity is evaluated.

СТРУКТУРА, МОДЕЛИ И СТРАТЕГИИ УЧАСТИЯ ГОРОДСКИХ СООБЩЕСТВ В КОНФЛИКТАХ

2020 ◽  
Vol 15 (2) ◽  
pp. 54
Author(s):  
А. И. Кольба ◽  
Н. В. Кольба
Keyword(s):  
Political Parties ◽  
Urban Communities ◽  
Municipal Government ◽  
Structural Characteristics ◽  
City Government ◽  
Expert Interviews ◽  
Competitive Strategies ◽  
Scientific Publications ◽  
The City

The article describes the structural characteristics of the urban communities of the city of Krasnodar and the related features that impact their participation in urban conflicts. This issue is considered in a number of scientific publications, but there is a need to expand the empirical base of such studies. On the base of expert interviews conducted with both city activists, their counterparty (representatives of the municipal government) and external observers (journalists), the parameters of urban communities functioning in the process of their interaction with other conflict actors are revealed. The communities characteristics such as the predominantly territorial principle of formation, the overlap of online and offline communications in their activities, the presence of a “core” with a relatively low number of permanent participants and others are determined. Their activities are dominated by neighborly and civilian models of participation in conflicts. The possibilities of realizing one’s own interests through political interactions (participation in elections, the activities of representative bodies of power, political parties) are not yet sufficiently understood. Urban communities, as a rule, operate within the framework of conventional forms of participation in solving urgent problems, although in some cases it is possible to use confrontational methods, in particular, protest ones. In this regard, the most often used compromise, with the desire for cooperation, a strategy of behavior in interaction with opponents. The limited activating role of conflicts in the activities of communities has been established. The weak manifestation of the civil and especially political component in their activities determines the preservation of a low level of political subjectivity. This factor restrains the growth of urban communities resources and the possibility of applying competitive strategies in interaction with city government and business.

Positive Role of Synthesis Method and Hard Template on the Catalytic Performance of SAPO-34 in Methanol to Olefin Reaction.

2020 ◽  
Vol 23 ◽  
Author(s):  
Sajjad Rimaz ◽  
Reza Katal
Keyword(s):  
Particle Size ◽  
Synthesis Method ◽  
Catalytic Performance ◽  
Hard Template ◽  
Structure Directing Agent ◽  
Positive Role ◽  
Methanol To Olefin ◽  
Dg Method ◽  
Synthesis Procedure

: In the present study, SAPO-34 particles were synthesized using hydrothermal (HT) and dry gel (DG) conversion methods in the presence of diethyl amine (DEA) as an organic structure directing agent (SDA). Carbon nanotubes (CNT) were used as hard template in the synthesis procedure to introduce transport pores into the structures of the synthesized samples. The synthesized samples were characterized with different methods to reveal effects of synthesis method and using hard template on their structure and catalytic performance in methanol to olefin reaction (MTO). DG conversion method results in smaller particle size in comparison with hydrothermal method, resulting in enhancing catalytic performance. On the other side, using CNT in the synthesis procedure with DG method results in more reduction in particle size and formation of hierarchical structure which drastically improves catalytic performance.

scholarly journals Thiophene-Based Compounds with Potential Anti-Inflammatory Activity

2021 ◽  
Vol 14 (7) ◽  
pp. 692
Author(s):  
Ryldene Marques Duarte da Cruz ◽  
Francisco Jaime Bezerra Mendonça-Junior ◽  
Natália Barbosa de Mélo ◽  
Luciana Scotti ◽  
Rodrigo Santos Aquino de Araújo ◽  
...  
Keyword(s):  
Inflammatory Diseases ◽  
Structural Characteristics ◽  
Tiaprofenic Acid ◽  
Inflammatory Activity ◽  
Drug Candidates ◽  
Biological Target ◽  
Inflammatory Drugs ◽  
Anti Inflammatory ◽  
Privileged Structures

Rheumatoid arthritis, arthrosis and gout, among other chronic inflammatory diseases are public health problems and represent major therapeutic challenges. Non-steroidal anti-inflammatory drugs (NSAIDs) are the most prescribed clinical treatments, despite their severe side effects and their exclusive action in improving symptoms, without effectively promoting the cure. However, recent advances in the fields of pharmacology, medicinal chemistry, and chemoinformatics have provided valuable information and opportunities for development of new anti-inflammatory drug candidates. For drug design and discovery, thiophene derivatives are privileged structures. Thiophene-based compounds, like the commercial drugs Tinoridine and Tiaprofenic acid, are known for their anti-inflammatory properties. The present review provides an update on the role of thiophene-based derivatives in inflammation. Studies on mechanisms of action, interactions with receptors (especially against cyclooxygenase (COX) and lipoxygenase (LOX)), and structure-activity relationships are also presented and discussed. The results demonstrate the importance of thiophene-based compounds as privileged structures for the design and discovery of novel anti-inflammatory agents. The studies reveal important structural characteristics. The presence of carboxylic acids, esters, amines, and amides, as well as methyl and methoxy groups, has been frequently described, and highlights the importance of these groups for anti-inflammatory activity and biological target recognition, especially for inhibition of COX and LOX enzymes.

scholarly journals Application of microwave radiation in the grafting of acidic sites on SBA-15 type material

2021 ◽  
Author(s):  
Maciej Trejda ◽  
Magdalena Drobnik ◽  
Ardian Nurwita
Keyword(s):  
Microwave Radiation ◽  
Thermal Analyses ◽  
Conventional Heating ◽  
Material Surface ◽  
Test Reaction ◽  
Study Materials ◽  
Mesoporous Support ◽  
Acidic Sites ◽  
Post Synthesis ◽  
Adsorption Desorption

AbstractMesoporous silica of SBA-15 type was modified for the first time with 3-(trihydroxysiyl)-1-propanesulfonic acid (TPS) by post-synthesis modification involving microwave or conventional heating in order to generate the Brønsted acidic centers on the material surface. The samples structure and composition were examined by low temperature N2 adsorption/desorption, XRD, HRTEM, elemental and thermal analyses. The surface properties were evaluated by esterification of acetic acid with n-hexanol used as the test reaction. A much higher efficiency of TPS species incorporation was reached with the application of microwave radiation for 1 h than conventional modification for 24 h. It was found that the structure of mesoporous support was preserved after modification using both methods applied in this study. Materials obtained with the use of microwave radiation showed a superior catalytic activity and high stability.

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