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MOF-based Electrochemical Sensors for Glucose
Published in Ram K. Gupta, Tahir Rasheed, Tuan Anh Nguyen, Muhammad Bilal, Metal-Organic Frameworks-Based Hybrid Materials for Environmental Sensing and Monitoring, 2022
Ummama Saeed, Rafia Batool, Dilshad Hussain, Saadat Majeed, Muhammad Najam-ul-Haq, Batool Fatima
Metal-organic frameworks contain metal ionic groups and linkers and because of these structures they are also known as organic-inorganic hybrid networks (Figure 22.1). They have different surface areas for micro, mesoporous and microporous materials. Microporous materials have a pore size of 2 nm, for example, zeolites and MOFs. Mesoporous materials have pore sizes fluctuating from 2 nm to 50 nm, for example, oxides of titanium, zirconium, and tin, sometimes silica and alumina are also reported [14]. Macro-porous materials have cavities with pore sizes of more than 50 nm [15]. Organic linkers and inorganic metal ions have the pre-decided agreement of inorganic metal atoms bounded by organic moieties which results in the formation of repeating units and greater surface area of the MOFs [16]. Ligands are used as organic units in which selection of ligand and metal is significant to find out the properties of the metal-organic frameworks. MOFs have well-organized composition, turnability, porousness, flexibility in network structure, and maximum surface area [17]. The nano porosity of the MOFs makes them leading materials over that of metal oxides and other zeolites in which an oxygen atom is replaced by the organic linker which binds with the inorganic ions and is considered to self-assemble into the one-,two-, and three dimensional MOFs [12]. Strong bonding between the metal ions and organic parts is responsible for their 1,2 and 3-dimensional crystalline structure.
Significance of Metal-Organic Frameworks Consisting of Porous Materials
Published in Anish Khan, Mohammad Jawaid, Abdullah Mohammed Ahmed Asiri, Wei Ni, Mohammed Muzibur Rahman, Metal-Organic Framework Nanocomposites, 2020
R. Kumar, Abdullah Arul Marcel Moshi, S.R. Sundara Bharathi, C. Dhanasekaran, S. Sivaganesan, P. Senthamaraikannan, S.S. Saravanakumar, Anish Khan
Microporous materials are used in valuable applications like redox catalysts, in the petroleum industry, and in the synthesis of chemical items for different kinds of shape-selective transformation and detachment processes. They create the fundamentals of new environment-friendly technologies which involve cheaper and more efficient conditions for performing chemical reactions. Transition metals modified microporous molecular filters with alumino silicate and aluminophosphate frameworks accelerate a wide range of artificially effective oxidizing transformations with impurity-free oxidants like hydrogen peroxide under comparably light conditions, providing the advantage of recovering and recycling complex structures. MOFs are utilized in a significant number of applications in waste treatment activities including detachment of heavy metals and radio active species, ammonia, various kinds of phosphates, and harmful gases from soil, water, and air because they have unique structural and physicochemical characteristics. In earlier times, silica-aluminum-based zeolite microporous materials were mainly used. In recent times, several types of microporous materials are being produced with the aid of metal oxides, metal phosphates, and inorganic-organic hydride materials [31].
Mesoporous Electrodes for Supercapacitors
Published in Inamuddin, Rajender Boddula, Mohammad Faraz Ahmer, Abdullah M. Asiri, Morphology Design Paradigms for Supercapacitors, 2019
Godlisten N. Shao, Talam E. Kibona
As it has been highlighted above, porous carbon plays a crucial role in electrochemical energy storage. The facilitation of energy storage mechanisms depends on the textural properties of the porous carbon. Microporous materials possess a pore diameter less than 2 nm, while the nanomaterials with the pore size ranging between 2 and 50 nm are mesoporous. Microporous nanomaterials exhibit high surface area, thus increasing sites for ion adsorption and high specific capacitance. In contrast, mesoporous nanomaterials exhibit moderate surface area but large pore size. The large pore sizes enhance specific capacitances by increasing the transfer of ions, thus decreasing the transfer resistances. Hence, the present chapter deals with mesoporous electrode for supercapacitors.
Thermocatalytic pyrolysis of agriculture waste biomass for the production of renewable fuels and chemicals
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Uplabdhi Tyagi, Neeru Anand, Arinjay Jain
The above-discussed studies conclude that the thermochemical pyrolysis of biomass requires an effective catalyst; however, the cited literature utilizes catalysts which are non-tuneable, less effective, and have low regeneration and high decomposition rate during pyrolysis. However, such catalysts can be re-activated but require harsh temperature and pressure conditions. This degrades the quality and selectivity of the pyrolytic products and increases the quantity of char during pyrolysis. Therefore, the present study proposes the utilization of meso and microporous catalysts which exhibit uniform channels and cavities, high adsorption capacity, advantageous electronic properties, and active sites with different strengths. Also, the synthesized mesoporous and microporous catalysts offer a number of catalytically relevant features such as high thermal and hydrothermal stability, large surface area, uniform pores and voids, large pore size, and pore volume.
Pb(II) removal and its adsorption from aqueous solution using zinc oxide/graphene oxide composite
Published in Chemical Engineering Communications, 2021
Siti Zu Nurain Ahmad, Wan Norharyati Wan Salleh, Norhaniza Yusof, Mohd Zamri Mohd Yusop, Rafidah Hamdan, Nor Asikin Awang, Nor Hafiza Ismail, Norafiqah Rosman, Norazlianie Sazali, Ahmad Fauzi Ismail
Figure 3 shows the image of the surface and EDX spectra of the synthesized GO and ZnO/GO. From the image, the GO was revealed to have a rough surface with uneven plane and some cavities throughout the whole surface (Samuel et al. 2018). Meanwhile, for ZnO/GO, there was an abundant amount of round-shape particles attached on top of the GO sheets (Sharma and Jha 2017). These round-shape particles were thought to be the successful modification of ZnO on top of the GO; they were distributed inside the boundary and border of the GO sheet, which indicated that the incorporation of ZnO and GO was achieved (Liu et al. 2018a). This was supported by the emergence of new peak of Zn –O stretching on FTIR spectra of the newly synthesized ZnO/GO materials (as shown later). The new peak confirmed the successful interaction occurred between ZnO and also GO. The numerous amount of ZnO particles have caused an increase in the cavities and porosities of the adsorbents, which results in an increase in surface area for the Pb(II) ion to adsorb. Microporous materials (pore size <2 nm) refining the selectivity of adsorption and separation, while macroporous materials (pore size >50 nm) and mesoporous materials (pore size between 2–50 nm) allowed different sizes of materials to pass through (Miaralipour et al. 2018). Thus, the adsorption capacity for cationic heavy metals Pb(II) ion was enhanced by the generous number of ZnO surrounding the GO, elevating the surface area.
Characterization of coal gasification slag-based activated carbon and its potential application in lead removal
Published in Environmental Technology, 2018
Figure 2(a) revealed the effect of KOH/CGS ratio on the N2 adsorption–desorption isotherms. The maximum adsorption amount was obtained at a ratio of 3.0, which is in line with the result for surface area. Samples presented similar isotherms which can be classified as type I according to the International Union of Pure and Applied Chemistry (IUPAC) classification. A steep increase of the adsorption amount at low pressure indicated the adsorption or condensation in the micropores. A plateau without any notable hysteresis at the middle branch of the isotherm indicated a well-developed microporous and mesoporous structure in a sample. The amount of adsorption increased abruptly near the saturation pressure and might be caused by active capillary condensation [16]. This kind of adsorption isotherm is typical for microporous materials with small amounts of mesopores. In addition, the PSDs of the samples shown in Figure 2(b) showed narrow peaks at pore width around 1.2–3.8 nm. Therefore, a ratio of 3.0 was chosen for the following experiments.