scholarly journals Catalase biosensor based on the PAni/cMWCNT support for peroxide sensing

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 476-490
Author(s):  
Angélica Domínguez-Aragón ◽  
Rocio B. Dominguez ◽  
María del Rosario Peralta-Pérez ◽  
Erasto Armando Zaragoza-Contreras
Keyword(s):  
Synergistic Effects ◽  
Direct Electron Transfer ◽  
High Surface ◽  
High Surface Area ◽  
Multiwalled Carbon ◽  
Detection Range ◽  
Carboxylic Groups ◽  
Average Recovery Rate ◽  
And Performance ◽  
Covalently Linked

Abstract Polymeric-based composites can contribute to enhancing the detection, stability, and performance of enzymatic biosensors, due to their high structural stability, conductivity, and biocompatibility. This work presents the fabrication of a nanocomposite of polyaniline (PAni)/gold nanoparticles (AuNP)/carboxylated multiwalled carbon nanotubes (cMWCNT) as functional support for covalently linked catalase (CAT) enzyme. PAni was electropolymerized on a screen-printed carbon electrode (SPCE) and decorated with AuNP to improve charge transfer properties. CAT was bonded through amide formation using the carboxylic groups of cMWCNT, resulting in PAni/AuNP/cMWCNT/CAT biosensor. The structural and electroactive characteristics of the nanocomposite were studied by SEM, FT-IR, and cyclic voltammetry. The optimal performance was achieved after CAT immobilization over PAni/AuNP/cMWCNT/nanocomposite, showing improved analytical features such as a fast amperometric response of 1.28 s, a wide detection range from 0.01 to 6.8 mM, a correlation coefficient (R 2) of 0.9921, a low detection limit of 2.34 µM, and an average recovery rate of 99.6% when evaluated in milk samples. Additionally, the bioelectrode showed excellent selectivity and retained bioactivity after 30 days of storage. Such remarkable performance proved the synergistic effects of both the high surface area of the cMWCNT and AuNP and the inherent PAni electroactivity, yielding direct electron transfer from CAT.

scholarly journals Solid State Electronic Sensors for Detection of Carbon Dioxide

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3848 ◽  
Author(s):  
Ami Hannon ◽  
Jing Li
Keyword(s):  
Carbon Dioxide ◽  
Iron Oxide ◽  
High Surface ◽  
High Surface Area ◽  
Multiwall Carbon Nanotubes ◽  
High Sensitivity ◽  
Space Applications ◽  
Detection Range ◽  
Ultra Low Power ◽  
Compact Size

Detection of carbon dioxide (CO2) is very important for environmental, health, safety and space applications. We have studied novel multiwall carbon nanotubes (MWCNTs) and an iron oxide (Fe2O3) nanocomposite based chemiresistive sensor for detection of CO2 at room temperature. The sensor has been miniaturized to a chip size (1 cm × 2 cm). Good sensing performance was observed with a wide detection range of CO2 concentrations (100–6000 ppm). Structural properties of the sensing materials were characterized using Field-Emission Scanning Electron Microscopy, Fourier-Transform Infrared and Raman spectroscopies. The greatly improved sensitivity of the composite materials to CO2 can be attributed to the formation of a depletion layer at the p-n junction in an MWCNT/iron oxide heterostructure, and new CO2 gas molecules adhere to the high surface area of MWCNTs due to the concentration gradient. The test results showed that the CO2 sensor possesses fast response, compact size, ultra-low power consumption, high sensitivity and wide dynamic detection range.

Rich N/O/S co-doped porous carbon with a high surface area from silkworm cocoons for superior supercapacitors

2019 ◽  
Vol 43 (48) ◽  
pp. 19372-19378 ◽  
Author(s):  
Jianyu Huang ◽  
Simin Liu ◽  
Zifang Peng ◽  
Zhuoxian Shao ◽  
Yuanyuan Zhang ◽  
...  
Keyword(s):  
Surface Area ◽  
Porous Carbon ◽  
Electrode Materials ◽  
Synergistic Effects ◽  
High Surface ◽  
High Surface Area ◽  
Porous Carbons ◽  
Co Doped

The synergistic effects of high surface area and abundant heteroatoms make porous carbons superior electrode materials.

scholarly journals Carbon-Based Catalysts for Biodiesel Production—A Review

2020 ◽  
Vol 10 (3) ◽  
pp. 918 ◽  
Author(s):  
Jack Clohessy ◽  
Witold Kwapinski
Keyword(s):  
Heterogeneous Catalysts ◽  
Catalyst Activity ◽  
High Surface ◽  
High Surface Area ◽  
Acid Catalyst ◽  
Biodiesel Production ◽  
Catalyst Characterization ◽  
Synthesis Methods ◽  
And Performance ◽  
Carbon Based

In recent years, a new class of superior heterogeneous acid catalyst for biodiesel production has emerged. These catalysts offer advantages over their predecessors such as high surface area, elevated acid site density, enhanced catalyst activity, good operation stability and relevant economic affordability in an environmentally friendly frame. This review was concerned with carbon-based solid acid (CBAS) catalysts derived from both carbohydrate and pyrolysis products. A series of CBASs with various origins such as D-glucose, sucrose, starch, cellulose and vegetable oil asphalt, converted to char and sulphonated, have been explored as potential heterogeneous catalysts. Catalyst preparation and synthesis methods were briefly summarized. Catalyst characterization and performance for biofuels related reactions were elucidated, identifying potential research applications. Three catalysts in particular were identified as having potential for industrial application and requiring further research.

scholarly journals Enzymatic Bioreactors: An Electrochemical Perspective

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1232
Author(s):  
Simin Arshi ◽  
Mehran Nozari-Asbemarz ◽  
Edmond Magner
Keyword(s):  
Direct Electron Transfer ◽  
High Surface ◽  
High Surface Area ◽  
Enzyme Engineering ◽  
Future Perspective ◽  
Enzymatic System ◽  
Reaction Conditions ◽  
Flow Reactors ◽  
Recent Developments ◽  
Enzyme Cascades

Biocatalysts provide a number of advantages such as high selectivity, the ability to operate under mild reaction conditions and availability from renewable resources that are of interest in the development of bioreactors for applications in the pharmaceutical and other sectors. The use of oxidoreductases in biocatalytic reactors is primarily focused on the use of NAD(P)-dependent enzymes, with the recycling of the cofactor occurring via an additional enzymatic system. The use of electrochemically based systems has been limited. This review focuses on the development of electrochemically based biocatalytic reactors. The mechanisms of mediated and direct electron transfer together with methods of immobilising enzymes are briefly reviewed. The use of electrochemically based batch and flow reactors is reviewed in detail with a focus on recent developments in the use of high surface area electrodes, enzyme engineering and enzyme cascades. A future perspective on electrochemically based bioreactors is presented.

Transport in Stochastic Fibrous Networks

2000 ◽  
Vol 123 (1) ◽  
pp. 12-19 ◽  
Author(s):  
X. Cheng ◽  
A. M. Sastry ◽  
B. E. Layton
Keyword(s):  
Volume Fraction ◽  
High Surface ◽  
High Surface Area ◽  
Statistical Technique ◽  
Porous Structures ◽  
Fibrous Materials ◽  
Aspect Ratios ◽  
And Performance ◽  
2D Network ◽  
Key Questions

Some fundamental issues concerning the design and performance of stochastic porous structures are examined, stemming from application of advanced fibrous electrode substrates in NiMH automotive cells. These electrodes must resist corrosion and local failures under hundreds of charge/discharge cycles. Such fibrous materials can be effectively used as substrates for chemical reactions because of their combinations of high surface area and high conductivity. Key questions concerning the relationships among connectivity and conductivity, scale and variability in material response are addressed. Two techniques are developed and compared for use in predicting these materials’ conductivity. The first approach uses a statistical technique in conjunction with an adaptation of classic micromechanical models. The second approach uses the statistical generation technique, followed by an exact calculation of 2D network conductivity. The two techniques are compared with one another and with classic results. Several important conclusions about the design of these materials are presented, including the importance of use of fibers with aspect ratios greater than at least 50, the weak effect of moderate alignment for unidirectional conductivity, and the weak power-law behavior of conductivity versus volume fraction over the range of possible behaviors.

scholarly journals Synthesis, Characterization and Performance of Low-Cost Unconventional Adsorbents Derived from Waste Materials

2020 ◽  
Vol 10 (6) ◽  
pp. 7243-7256 ◽  
Keyword(s):  
Adsorption Mechanism ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Kinetic Studies ◽  
Maximum Adsorption Capacity ◽  
Batch Experiments ◽  
Adsorbate Concentration ◽  
Optimum Ph ◽  
And Performance

Adsorption of the solute on solid is an equilibrium operation. The nature of adsorbent affects the efficiency of the operation. High surface area per unit volume is the essential attribute of a good adsorbent. Isotherm and kinetic studies are carried out to understand the adsorption mechanism. Many investigators have carried out batch experiments to study the effect of various parameters like initial adsorbate concentration, pH, particle size, and adsorbent dose. The use of adsorbents derived from low-cost materials makes this operation acceptable in industries. Regeneration of adsorbent can reduce the problem of disposal of used adsorbent material. Optimum values of affecting parameters can be determined from batch experiments. The isotherm and kinetic constants can be determined from batch experiments. These investigations give us an idea about the nature of adsorbent, maximum adsorption capacity, the order of adsorption, and optimum pH. This review sheds light on investigations on adsorbents derived from unconventional adsorbents and their characterization and performance evaluation.

Investigation of BTEX Adsorption on Carbon Nanotubes Cartridges from Air Samples

2019 ◽  
Vol 889 ◽  
pp. 216-222 ◽  
Author(s):  
Huu Quynh Anh Le ◽  
Dinh Tuan Phan
Keyword(s):  
Carbon Nanotubes ◽  
Adsorption Capacity ◽  
Flow Rate ◽  
Gas Flow ◽  
High Surface ◽  
High Surface Area ◽  
Operating Conditions ◽  
Multiwalled Carbon ◽  
Air Samples ◽  
Environmental Treatment

The volatile organic compounds (VOCs) contribute to serious air pollution problems in Viet Nam. Many studies have investigated in air quality monitoring and treatment, in order to determine the average concentrations of Benzene, Toluene, Ethylbenzene and Xylene (BTEX). Carbon nanotubes (CNTs) have been widely used as adsorbent in environmental treatment, especially for VOCs. This paper aims to determine the adsorption capacity of multiwalled carbon nanotubes for removal of BTEX from air samples. In preliminary study, the effects of various parameters during adsorption experiments were monitored such as flow rate, temperature and BTEX concentrations in air samples. The equipment for BTEX removal was developed by our research team consisting of filter columns, air sample bags, adsorption cartridge. The air samples containing BTEX were conducted directly through a cartridge packed with adsorbent. The adsorption experiments were carried out under various operating conditions such as temperature (30 - 40°C), gas concentration (0,57 - 4,77 mg/L) and the gas flow rate (10 - 90 mL/min). In addition, isotherm studies of CNTs for BTEX removal were achieved by using Langmuir and Freundlich models. The results showed that the experimental parameters were optimized at a flow rate of 30 mL/min and an ambient temperature at 30°C. The adsorption capacity of CNTs increased proportionally with BTEX concentrations. The specific affinity of CNTs for BTEX from air samples was in order of X > E > T > B. The experimental isotherm data were well-fit with the Langmuir model for Benzene and Xylene removal, and the Freundlich model for Toluene and Ethylbenzene adsorption. The CNTs presented highly potential application for BTEX adsorption thanks to their microporous structure and high surface area.

FACILE FUNCTIONALIZATION OF sp2 CARBON ALLOTROPES WITH A BIOBASED JANUS MOLECULE

2017 ◽  
Vol 90 (2) ◽  
pp. 285-307 ◽  
Author(s):  
M. Galimberti ◽  
V. Barbera ◽  
S. Guerra ◽  
A. Bernardi
Keyword(s):  
Carbon Materials ◽  
Mechanical Energy ◽  
High Surface ◽  
High Surface Area ◽  
Appreciable Effect ◽  
Multiwalled Carbon ◽  
Carbon Allotrope ◽  
Carbon Allotropes ◽  
Vulcanization Kinetics ◽  
Appreciable Reduction

ABSTRACT A simple, versatile, sustainable, not expensive method for the functionalization of sp2 carbon allotropes, both nano-sized and nano-structured, without altering their bulk crystalline organization, is presented. Carbon materials available at the commercial scale were used: furnace carbon black (CB), nano-sized graphite with high surface area, and multiwalled carbon nanotubes. A bio-sourced molecule, 2-(2,5-dimethyl-1H-pyrrol-1-yl)-1,3-propanediol (serinol pyrrole), was used for the functionalization. Serinol pyrrole (SP) was obtained from serinol through a reaction with atomic efficiency of about 82%, performed in the absence of solvents or catalysts. Synthesis of serinol pyrrole was performed as well on carbon allotropes as the solid support. Adducts of serinol pyrrole with a carbon allotrope were prepared with the help of either thermal or mechanical energy. Functionalization yield was in all cases larger than 90%. With such adducts, stable dispersions in water and in NR latex were prepared. A few layers of graphene were isolated from the water dispersions, and NR-based composites precipitated from the latex revealed very even distribution of fine graphitic particles. Composites were prepared, based on NR, IR, and BR as the rubbers and CB and silica as the fillers, with different amounts of CB–SP adduct, and were cross-linked with a sulfur-based system without observing appreciable effect of functionalization on vulcanization kinetics. The CB–SP adduct led to appreciable reduction of the Payne effect.

scholarly journals Mesoporous Graphitic Carbon Nitrides Decorated with Cu Nanoparticles: Efficient Photocatalysts for Degradation of Tartrazine Yellow Dye

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 636 ◽  
Author(s):  
Tao Zhang ◽  
Isis Souza ◽  
Jiahe Xu ◽  
Vitor Almeida ◽  
Tewodros Asefa
Keyword(s):  
Silica Nanoparticles ◽  
Surface Area ◽  
Synergistic Effects ◽  
High Surface ◽  
High Surface Area ◽  
Graphitic Carbon ◽  
Charge Carriers ◽  
High Porosity ◽  
Cu Nanoparticles ◽  
Excellent Photocatalytic Activity

A series of mesoporous graphitic carbon nitride (mpg-C3N4) materials are synthesized by directly pyrolyzing melamine containing many embedded silica nanoparticles templates, and then etching the silica templates from the carbonized products. The mass ratio of melamine-to-silica templates and the size of the silica nanoparticles are found to dictate whether or not mpg-C3N4 with large surface area and high porosity form. The surfaces of the mpg-C3N4 materials are then decorated with copper (Cu) nanoparticles, resulting in Cu-decorated mpg-C3N4 composite materials that show excellent photocatalytic activity for degradation of tartrazine yellow dye. The materials’ excellent photocatalytic performance is attributed to their high surface area and the synergistic effects created in them by mpg-C3N4 and Cu nanoparticles, including the Cu nanoparticles’ greater ability to separate photogenerated charge carriers from mpg-C3N4.

Atomic Layer Deposition on Quantities of Multiwalled Carbon Nanotubes

2007 ◽  
Vol 1054 ◽  
Author(s):  
Andrew S. Cavanagh ◽  
Christopher A. Wilson ◽  
Alan W. Weimer ◽  
Steven M. George
Keyword(s):  
Carbon Nanotubes ◽  
Atomic Layer Deposition ◽  
Multiwalled Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
High Surface ◽  
High Surface Area ◽  
Atomic Layer ◽  
Multiwalled Carbon ◽  
Transmission Electron ◽  
Layer Deposition

ABSTRACTAtomic layer deposition (ALD) was performed on quantities of multiwalled carbon nanotubes (MWCNTs) in a rotary reactor. Because of nucleation difficulties, Al2O3 ALD grew as nanospheres on the MWCNTs. After a NO2 nucleation treatment, Al2O3 ALD films grew conformally and noncovalently functionalized the surface of the MWCNT. This Al2O3 ALD film served as a platform for the growth of W ALD metal. The uncoated and ALD-coated MWCNTs were characterized with transmission electron microscopy and x-ray photoelectron spectroscopy. This study demonstrates that ALD can be performed on quantities of very high surface area MWCNT substrates.

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