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Mesoporous Materials in Heterogeneous Catalysis
Published in Varun Rawat, Anirban Das, Chandra Mohan Srivastava, Heterogeneous Catalysis in Organic Transformations, 2022
Meenal Batra, Ashutosh Sharan Singh
Molecular pores or voids provide a confined environment than the bulk phase. These pores may be constrained or flexible depending upon the wall of molecular architecture and target molecule of consideration. Zeolites [1] are natural porous architectures and scientists have attempted to mimic such pores in an artificial system which may be synthesized either through coordinate bond between metal cations (acts as node) and judicial choice of an organic framework (known as linker) or through condensation of purely organic framework. The former is explored as metal–organic frameworks (MOFs) [2] and the latter is known as covalent organic frameworks (COFs) [3]. Depending upon the range of pore size, materials are classified as microporous, mesoporous and macroporous, respectively. Materials of pore size in the range of 2–50 nm are known as mesoporous materials. The word “Mesoporous” is of Greek origin, which signifies having a pore size of diameter in between micro (less than 2 nm) and macro (more than 50 nm) materials.
Porous Inorganic Nanomaterials for Drug Delivery
Published in Vladimir Torchilin, Handbook of Materials for Nanomedicine, 2020
Elshaimaa Sayed, Yasmine Alyassin, Aliyah Zaman, Ketan Ruparelia, Neenu Singh, Ming-Wei Chang, Zeeshan Ahmad
The International Union of Pure and Applied Chemistry (IUPAC) has used the term meso (in between) to characterize materials which have pores between the macropore and the micropore range (2–50 nm). Additionally, based on the nature of their porous network, IUPAC identifies mesoporous materials into ordered or disordered materials [32]. Mesoporous materials are emerging as attractive platforms for designing diverse types of drug delivery systems. For years, great efforts have been witnessed to develop mesoporous materials with varying chemical structures, porous architectures and functionalities [33, 34]. Various types of mesoporous materials have been employed as drug delivery matrices such as mesoporous silica [35–41], mesoporous carbon [42, 43], alumina [44, 45], zirconia [46], titanium oxide [47] and various composites [48, 49].
Mesoporous Silica: the Next Generation Energy Material
Published in Ranjusha Rajagopalan, Avinash Balakrishnan, Innovations in Engineered Porous Materials for Energy Generation and Storage Applications, 2018
Saika Ahmed, M. Yousuf Ali Mollah, M. Muhibur Rahman, Md. Abu Bin Hasan Susan
The usual method for creation of pores in mesoporous materials, or in specific, mesoporous silica is through the use of supramolecular aggregates like micellar array of surfactants as templates, known as ‘soft-templates’ while the method is termed ‘soft-templating method’. The surfactants in this case are referred to as ‘structure-directing agents’, since their structure and nature are crucial factors in templating the mesoporous materials. Such surfactants, when present in low concentrations in water, produce micellar aggregates; while in high concentrations, produce liquid-crystal like structures. Hydrothermal conditions are generally employed for the synthesis. Both acidic and basic conditions have been successfully used till date. The silica source, usually inorganic silicates are efficiently adsorbed on to the hydrophilic outward portion of the surfactant aggregates due to electrostatic interactions. The surfactant template is then removed by calcination at high temperature, leaving regular, ordered pores in the silica structure.
3D Printing of Shrimp Derived Chitosan with HAp as a Bio-Composite Scaffold
Published in Materials and Manufacturing Processes, 2022
N Pradeep, C Chandrasekhara Sastry, Lc Brandão, B.S. Meennakshi
The porosity level within the powder ensures interconnectivity across the scaffold. Hence, the porosity size (Ø) was quantified using Bruker Emmet-Teller (BET) analysis as shown in Fig. 8(b). Chitosan of 0.1 gm and Composite powder of 0.1 gm were analyzed for porosity volume and size using the BJH model by passing nitrogen gas. The adsorption level of the powder(s) determines the value as tabulated in Table 5. It was observed that the composite powder particles are mesoporous with avg. porosity diameter of 3.71 nm. Also, the chitosan powder reported having 23% increased porosity diameter. The decrease in porosity of the composite powder may be due to the increased agglomeration of the composite under the influence of N2 adsorption. The advantage of having such mesoporous materials extends to the strong loading of drugs for drug delivery application.[32]
Influence of Vanadium incorporated mesoporous silica on the decolorization of orange G under visible light irradiation
Published in Inorganic and Nano-Metal Chemistry, 2022
Mahesh Chandra, Muralasetti Nookaraju, Vijay Kumar Sharma, Ryali Somasekhar
In recent years, porous materials have been the focus of material scientists due to their applications in various fields specifically in heterogeneous catalysis [28–32]. During the past two decades substantial progress has been made in the field of mesoporous materials successfully [33,34]. Mesoporous materials have received attention owing of their potential applications in catalysis, separation, selective adsorption and preparing novel functional materials [35]. These applications are possible due to the extremely high surface area combined with large and uniform pore size of mesoporous materials and tenability of surface characteristics [36]. Furthermore, these materials have high thermal stability and adsorption capacity [36,37]. Being their suitability toward photocatalytic removal of hazardous dyes, several investigations have been reported on the role of mesoporous MCM-41 materials in the phenomenon of photocatalysis [38]. The material has flourished as a novel catalyst of its own kind than its analogs like MCM-48 (cubic), MCM-50 (lamellar) materials [39]. MCM-41 can promote the reaction process even with bulkier and sterically clouded molecules by incorporating a suitable surfactant of choice. Hence, these mesoporous materials have attracted the attention of the researchers to study its effective role in the liquid phase oxidation processes [40–45].
Synthesis, characterisation and electrochemical evaluation of a functionalised coating for mild steel corrosion protection
Published in Surface Engineering, 2019
Victoria Bustos-Terrones, Jorge Uruchurtu, Jesús J. Rochín-Medina, Karina Ramírez, Jesús G. Rangel-Peraza, Mario A. Romero-Romo, Yaneth Bustos-Terrones
Mesoporous materials have become an interesting field of study, in particular as controlled drug delivery systems because of their high potential for drug activity optimisation by keeping drug delivering stationary. SBA-15 is an ordered mesoporous material with a hexagonal packaging, with uniform size cylindrical pores (2–50 nm diameter), high specific surface area (around 1000 m2 g−1), large pore volume (up to 1 cm3 g−1), and chemical and thermal stability. Surface activity of SBA-15 has been attributed to the presence of different concentrations of silanol (–Si–OH) and siloxane groups (–Si–O–Si–) within the rods’ surface. Therefore, the adjustment of these parameters allows the control of the loading and release kinetics of a specific substance. Recently these materials have been of great interest, not only for medical applications (as drug delivery systems) [1-9], but also for other areas of science, such as biology [10], chemistry [11], physics [12], and electrochemistry [13,14]. Several research works have demonstrated that, when this material is used in drug delivery systems, mesoporous silica materials show an excellent response for the gradual release of the drug particles [5-7].