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Showing papers on "Thermogravimetric analysis published in 2021"


Journal ArticleDOI
TL;DR: In this paper, the authors synthesized polymer gel beads based on functionalized iron oxide (Fe3O4), activated charcoal (AC) particles with β-cyclodextrin (CD) and sodium alginate (SA) polymer (Fe 3O4/CD/AC/SA), by a simple, reproducible and inexpensive method.

112 citations


Journal ArticleDOI
TL;DR: In this article, a chitosan-montmorillonite/polyaniline (CH-Mt/PANI) nanocomposite was synthesized by the intercalation of CH into Mt through ion-exchange process followed by the impregnation of aniline.

110 citations


Journal ArticleDOI
TL;DR: Kinetics, equilibrium and thermodynamic process were discussed in detailed, suggesting the endothermic and spontaneous process of the adsorption of MO dye on the exterior of films can be applied on large scale applications and can be easily adjustable in the water purification assemblies.

94 citations


Journal ArticleDOI
01 Aug 2021-Polymers
TL;DR: In this article, the effect of chemical treatments used on cellulose natural fiber-reinforced thermoplastic and thermosetting polymer composites has been reviewed and the TGA data are useful as guidance in determining the purity and composition of the composites' structures, drying and the ignition temperatures of materials.
Abstract: Natural fiber such as bamboo fiber, oil palm empty fruit bunch (OPEFB) fiber, kenaf fiber, and sugar palm fiber-reinforced polymer composites are being increasingly developed for lightweight structures with high specific strength in the automotive, marine, aerospace, and construction industries with significant economic benefits, sustainability, and environmental benefits. The plant-based natural fibers are hydrophilic, which is incompatible with hydrophobic polymer matrices. This leads to a reduction of their interfacial bonding and to the poor thermal stability performance of the resulting fiber-reinforced polymer composite. Based on the literature, the effect of chemical treatment of natural fiber-reinforced polymer composites had significantly influenced the thermogravimetric analysis (TGA) together with the thermal stability performance of the composite structure. In this review, the effect of chemical treatments used on cellulose natural fiber-reinforced thermoplastic and thermosetting polymer composites has been reviewed. From the present review, the TGA data are useful as guidance in determining the purity and composition of the composites’ structures, drying, and the ignition temperatures of materials. Knowing the stability temperatures of compounds based on their weight, changes in the temperature dependence is another factor to consider regarding the effectiveness of chemical treatments for the purpose of synergizing the chemical bonding between the natural fiber with polymer matrix or with the synthetic fibers.

90 citations


Journal ArticleDOI
10 Jan 2021-Polymers
TL;DR: In this article, two different types of hybrid porous organic polymers (POPs), polyhedral oligomeric silsesquioxane tetraphenylpyrazine (POSS-TPP), were successfully synthesized through the Friedel−Crafts polymerization of tetraphhenyl pyrazine, respectively, with octavinylsilsesquioxanes (OVS) as node building blocks, in the presence of anhydrous FeCl3 as a catalyst and 1,2-dichloroethane at 60 °C.
Abstract: In this study, two different types of hybrid porous organic polymers (POPs), polyhedral oligomeric silsesquioxane tetraphenylpyrazine (POSS-TPP) and tetraphenylethene (POSS-TPE), were successfully synthesized through the Friedel−Crafts polymerization of tetraphenylpyrazine (TPP) and tetraphenylethene (TPE), respectively, with octavinylsilsesquioxane (OVS) as node building blocks, in the presence of anhydrous FeCl3 as a catalyst and 1,2-dichloroethane at 60 °C. Based on N2 adsorption and thermogravimetric analyses, the resulting hybrid porous materials displayed high surface areas (270 m2/g for POSS-TPP and 741 m2/g for POSS-TPE) and outstanding thermal stabilities. Furthermore, as-prepared POSS-TPP exhibited a high carbon dioxide capacity (1.63 mmol/g at 298 K and 2.88 mmol/g at 273 K) with an excellent high adsorption capacity for iodine, reaching up to 363 mg/g, compared with the POSS-TPE (309 mg/g).

73 citations


Journal ArticleDOI
15 Mar 2021-Energy
TL;DR: In this paper, the physicochemical compatibility between CA-SA eutectic PCM and silica fume (SF) was studied by fourier transform infrared (FTIR), X-ray powder diffraction (XRD) and scanning electron microscope (SEM) techniques.

70 citations


Journal ArticleDOI
TL;DR: The synthetized nanocomposite can be a suitable new absorbent for ibuprofen and paracetamol removal from aqueous solutions due to its high adsorbing capacity and it can be separated by an external magnetic field.

68 citations


Journal ArticleDOI
TL;DR: In this paper, four different fluorescent hybrid microporous polymers (HPPs) derived from cubic octavinylsilsquioxane (OVS) through Heck coupling with brominated anthracene (An-Br2), triphenyltriazine (TPT-Br3), bicarbazole (Car-Br4), and tetraphenylethene (TPE-br4) were confirmed using Fourier transform infrared spectroscopy and solid-state NMR spectrograms.

66 citations


Journal ArticleDOI
TL;DR: Cellulose nanocrystals were produced from cotton using ultrasound treatment to enhance the structural and thermal properties and crystallinity of CNCs has been increased due to the combined effect.

65 citations


Journal ArticleDOI
27 Apr 2021
TL;DR: In this article, the authors presented a comprehensive TGA study to determine the influence of different particle size of the three key materials including graphene, graphene oxide and graphite on their thermal parameters such as carbon decomposition range and its temperature of maximum mass change rate.
Abstract: Thermogravimetric analysis (TGA) has been recognized as a simple and reliable analytical tool for characterization of industrially manufactured graphene powders. Thermal properties of graphene are dependent on many parameters such as particle size, number of layers, defects and presence of oxygen groups to improve the reliability of this method for quality control of graphene materials, therefore it is important to explore the influence of these parameters. This paper presents a comprehensive TGA study to determine the influence of different particle size of the three key materials including graphene, graphene oxide and graphite on their thermal parameters such as carbon decomposition range and its temperature of maximum mass change rate (Tmax). Results showed that Tmax values derived from the TGA-DTG carbon combustion peaks of these materials increasing from GO (558–616 °C), to graphene (659–713 °C) and followed by graphite (841–949 °C) The Tmax values derived from their respective DTG carbon combustion peaks increased as their particle size increased (28.6–120.2 µm for GO, 7.6–73.4 for graphene and 24.2–148.8 µm for graphite). The linear relationship between the Tmax values and the particle size of graphene and their key impurities (graphite and GO) confirmed in this study endows the use of TGA technique with more confidence to evaluate bulk graphene-related materials (GRMs) at low-cost, rapid, reliable and simple diagnostic tool for improved quality control of industrially manufactured GRMs including detection of “fake” graphene.

62 citations


Journal ArticleDOI
TL;DR: In this paper, the performance of nano-enhanced phase changing materials (nano-PCMs) in terms of their thermal storage properties is investigated for renewable energy-based thermal systems such as solar thermal collectors.

Journal ArticleDOI
TL;DR: In this article, a graphene oxide-manganese dioxide (GO-MnO2) nanocomposite was synthesized using a hydrothermal method to reduce pollution load of wastewater.
Abstract: The presence of anionic and cationic dyes in wastewater has highlighted a great necessity to develop new and effective approaches for their simultaneous removal. Herein, graphene oxide-manganese dioxide (GO-MnO2) nanocomposite was synthesized using a hydrothermal method to reduce pollution load of wastewater. In this stidy, synthesized material was utilized as adsorbent for the removal of cationic methylene blue (MB) and anionic methyl orange (MO) dyes from aqueous solution that act as model organic pollutants. The morphology, chemical structure, thermal stability, and other properties of the synthesized adsorbent were characterized using Field emmision scanning electron microscopy, Powder X-ray differaction, Raman spectroscopy, Fourier transform infrared spectra, Energy dispersive spectroscopy, Thermogravimetric analysis, and Brunauer-Emmett-Teller surface area techniques. The kinetics results showed the removal efficiency of 50.48% and 85.35% within the starting 5 min for both MO and MB, respectively, and fitted well to a pseudo-second-order kinetics model. The isotherms adsorption results fitted well to the Langmuir isotherm model, confirming the monolayer adsorption and give maximum adsorption capacities 149.253 and 178.253 mg/g for MO and MB, respectively. GO-MnO2 showed a good reusability and gave > 90% removal efficiencies after seven continuous cycles. Lastly, the simultaneous adsorption performance of the adsorbent for both dyes ggave 100% removal efficiency. All these results give a direct visual impression of the fast kinetics efficiency and high adsorption capacity for real wastewater treatment application.

Journal ArticleDOI
11 Mar 2021-Langmuir
TL;DR: In this paper, a single-step hydrothermal strategy was used to synthesize heteroatom-doped fluorescent carbon quantum dots (C-dots), which could serve as an antioxidant.
Abstract: This work presents the facile synthesis of heteroatom-doped fluorescent carbon quantum dots (C-dots), which could serve as an antioxidant. Herein, nitrogen, phosphorous, and sulfur codoped carbon dots (NPSC-dots) have been synthesized by a single-step hydrothermal strategy. Owing to the radical scavenging activity of the NPSC-dots, they were tested against several methods as well as in practical applications. The antioxidant ability of the NPSC-dots was efficiently utilized on plastic films by coating with these NPSC-dots. For the very first time, NPSC-dots were immobilized onto nonpolar plastic films (polypropylene) via photochemical covalent grafting to extend the shelf life of food items or storage without affecting the quality of plastic films. The NPSC-dot-coated PP film with negligible deterioration of transparency was extensively studied using scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR) analysis, X-ray photoelectron spectroscopy (XPS), contact angle measurement, and thermogravimetric analysis (TGA). The fluorescent character, antioxidant ability, and durability under different solvent systems of the coated film were examined. Also, the coated films were extensively and rigorously evaluated against simulated drastic environmental conditions to ensure the durability and antifogging application.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the thermal behavior, kinetics and thermodynamics of sewage sludge (SS) and low-density polyethylene (LDPE) and their blends during co-pyrolysis.
Abstract: This study investigates, for the first time, the thermal behaviors, kinetics and thermodynamics of sewage sludge (SS) and low-density polyethylene (LDPE) and their blends during co-pyrolysis. SS and LDPE co-pyrolysis were examined through thermogravimetric analysis (TGA) using different mixtures and multiple heating rates method. A positive interaction caused by the co-pyrolysis of SS and LDPE has been confirmed by the improved weight loss rate and devolatilization. Discrepancies between theoretical and experimental TGA/DTG curves as a measurement of the extent of synergic effect proved the existence of chemical interactions during the co-pyrolysis between the SS and LDPE blends of 1:1 and 1:2 ratios. The activation energy and reaction order for raw materials and their blends were studied by Coats-Redfern model. SS and LDPE blend of 1:1 ratio was optimal as it decreased the activation energy. Meanwhile, kinetics and thermodynamics were obtained from Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO) and Starink methods. Where the activation energies (76.73–355.83 kJ/mol), Gibbs free energy (116.92–123.04 kJ/mol) and lower difference of enthalpy (ΔH=∼6 kJ/mol) showed a promising potential to convert abundant and low-cost bio-solid wastes into bioenergy. This study provides a theoretical groundwork for co-pyrolysis of SS and LDPE.

Journal ArticleDOI
TL;DR: In this article, two types of meso/microporous carbon materials were successfully synthesized through carbonization and potassium hydroxide (KOH) activation for two different kinds of hyper-crosslinked polymers of TPE-CPOP1 and TPECPOP2, which were synthesized by using Friedel-Crafts reaction of tetraphenylethene (TPE) with or without cyanuric chloride in the presence of AlCl3 as a catalyst.
Abstract: In this study, we successfully synthesized two types of meso/microporous carbon materials through the carbonization and potassium hydroxide (KOH) activation for two different kinds of hyper-crosslinked polymers of TPE-CPOP1 and TPE-CPOP2, which were synthesized by using Friedel-Crafts reaction of tetraphenylethene (TPE) monomer with or without cyanuric chloride in the presence of AlCl3 as a catalyst The resultant porous carbon materials exhibited the high specific area (up to 1100 m2 g-1), total pore volume, good thermal stability, and amorphous character based on thermogravimetric (TGA), N2 adsoprtion/desorption, and powder X-ray diffraction (PXRD) analyses The as-prepared TPE-CPOP1 after thermal treatment at 800 °C (TPE-CPOP1-800) displayed excellent CO2 uptake performance (174 mmol g-1 at 298 K and 319 mmol g-1 at 273 K) Furthermore, this material possesses a high specific capacitance of 453 F g-1 at 5 mV s-1 comparable to others porous carbon materials with excellent columbic efficiencies for 10,000 cycle at 20 A g-1

Journal ArticleDOI
TL;DR: In this paper, a shape-stabilized phase change materials (SSPCMs) made from polyethylene glycol (PEG) and diatom-based biomass were reported.



Posted ContentDOI
TL;DR: In this article, a chitosan polymer was magnetized by coating with magnetite Fe2O3 nanoparticles, and the resultant material was then employed as a separable and efficient adsorptive agent to remove acid blue 113 (AB113) dye from aqueous solution.
Abstract: A chitosan polymer was magnetized by coating with magnetite Fe2O3 nanoparticles, and the resultant material (C-Fe2O3) was first characterized through scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy, transmission electron microscopy, atomic force microscopy, thermogravimetric, X-ray diffractometry, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller, and point of zero charge analyses. C-Fe2O3 was then employed as a separable and efficient adsorptive agent to remove acid blue 113 (AB113) dye from aqueous solution. The removal efficiency was optimized at different environmental parameter values (pH 3–11, C-Fe2O3 dose: 0.1–1 g/L, initial AB113 dye concentration: 10–100 mg/L, adsorption time: 0–300 min, and temperature: 15–45 °C). Under optimum conditions, an AB113 dye removal efficiency of 99.68% was achieved. In addition, the effect of the presence of NaCl, NaNO3, Na2CO3, and MgSO4 ions on the AB113 dye removal efficiency could be ranked as NaCl > NaNO3 > MgSO4 > Na2CO3. The statistical analysis using the coefficient of determination, root mean square error, chi-square test, sum of squared errors, and average relative error showed that the Freundlich and pseudo-second-order equations were the best mathematical models for fitting the isothermal and kinetics data. Further kinetics analyses showed that the adsorption of AB113 molecules on C-Fe2O3 active sites was dominated by the intraparticle diffusion process. Thermodynamic parameters indicated that the AB113 dye adsorption process was favorable, endothermic, and spontaneous. Furthermore, an increase in temperature had a positive impact on AB113 dye removal. The regeneration study confirmed the excellent shelf life of C-Fe2O3, with only a slight loss in the removal efficiency (< 7%) being detected after six operational cycles of AB113 dye adsorption. Compared with other adsorbents, C-Fe2O3 was more effective for the adsorption of AB113 dye, with an adsorption uptake up to 128 mg/g.

Journal ArticleDOI
01 Jan 2021
TL;DR: In this article, mesoporous silica nanoparticles (MSN) were synthesized using rice husk (RH) as the raw material via sol-gel pathway using cetyltrimethylammonium bromide (CTAB) as structure directing agent.
Abstract: Mesoporous silica nanoparticles (MSN) were synthesized using rice husk (RH) as the raw material via sol-gel pathway using cetyltrimethylammonium bromide (CTAB) as the structure directing agent. Silica nanoparticles were successfully functionalized with 3-aminopropyl triethoxysilane (APTES) via in-situ and post functionalization methods. Synthesized nanoparticles were characterized by X-Ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) surface area analysis. The amorphous silica nanoparticles were of 50–60 ​nm in diameter with a surface area of 150 ​m2/g, pore volume of 0.237 ​cm3/g and average pore size of 3.62 ​nm. Morphology and textural parameters were changed upon functionalization. The equilibrium adsorption capacity of MSN-A (4.94 ​mg/g) to adsorb 10 ​mg/L methylene blue (MB), was higher than in amine functionalized silica nanoparticles. The influence of experimental factors such as pH, adsorbent dosage, and initial MB concentration on adsorption of MB to MSN-A were studied. The equilibrium data for MB adsorption on mesoporous silica nanoparticles well fitted to Langmuir equation, with a maximum monolayer capacity of 19.26 ​mg/g. The adsorption of MB could be best described by the pseudo-second order model. The results indicate that MSN-A is a potential mesoporous material fabricated by cheap natural resources to remove MB from aqueous solutions.

Journal ArticleDOI
TL;DR: In this paper, nano-ZnO nanoparticles were embedded with the commercial grade paraffin and samples were prepared to find its improvement for using them as thermal energy storage elements.

Journal ArticleDOI
TL;DR: In this article, the removal efficiency of the obtained adsorbents was tested using indigo carmine (IC) at different pH, as a model dye, in both distilled water and textile wastewater.
Abstract: Activated carbons have been prepared from rice husk (RH) and coffee husk (CH) using ZnCl2 as activating agent. These materials were characterized by thermogravimetric and elemental analysis, infrared spectroscopy (FTIR), the point of zero charge (PZC), scanning electron microscopy (SEM), and nitrogen adsorption. The removal efficiency of the obtained adsorbents was tested using indigo carmine (IC) at different pH, as a model dye, in both distilled water and textile wastewater. The results showed that the dye adsorption on the natural adsorbents and the activated carbons was favorable at acidic pH (3.0). Moreover, the best IC removal in both matrices was reached by the material prepared from CH and activated with ZnCl2 (CH-ZnCl2). This result correlated well with the higher value PZC (7.1), large specific surface area, and porosity characteristics. Additionally, the dye adsorption on the CH-ZnCl2 surface was improved using the smaller particle size and the optimal dose of adsorbent; the adsorptions obtained were much better than those of a commercial activated carbon. Furthermore, the isotherms study showed the adsorption to be monolayer type according to Langmuir and Redlich-Peterson equations. The adsorption kinetics followed a pseudo-second-order kinetic model, and intra-particle diffusion showed that IC adsorption on the surface is faster than inside CH-ZnCl2. The thermodynamic parameters suggest that the IC adsorption is a physical process, which is spontaneous and endothermic. According to density functional theory calculations and experimental FTIR analysis, oxygenated groups and aromatic rings are relevant during the IC adsorption through hydrogen bonds and π-π interactions.

Journal ArticleDOI
TL;DR: In this article, the structure and morphology of the composites were analyzed by means of characterization, such as X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscope (SEM), transmission electron microscopic (TEM), Xray photoelectron spectroscopy (XPS), thermogravimetric (TG) analysis, and Raman.
Abstract: Copper manganese oxide-graphene (CuMn2O4-RGO) composite was prepared by sol-gel method and then synthesized by physical grinding, which was further applied to electrode materials for supercapacitors. The structure and morphology of the composites were analyzed by means of characterization, such as X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscope (SEM), transmission electron microscopic (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric (TG) analysis, and Raman. The electrochemical tests including cyclic voltammetry (CV), galvanostatic charge-discharge, electrochemical impedance spectroscopy (EIS) and cyclic life were used to investigate electrochemical properties of CuMn2O4-RGO so as to optimize its composition. Through the comparison of electrochemical properties at different mass ratios, current densities and scan rates, it was found that when the mass ratio was m (CuMn2O4): m (RGO) =1:1, the as-prepared CuMn2O4-RGO exhibited the excellent electrochemical properties. The capacitance reached 342 F g−1 at the current density of 1.0 A g−1, which was significantly higher than that of pure CuMn2O4 and RGO. The higher capacitance performance can be comparable with the reported literature value. Meanwhile, the energy density of CuMn2O4-RGO (1:1) is significantly higher than that of CuMn2O4 and RGO. Therefore, CuMn2O4-RGO (1:1) composite has a good prospect as electrode material for supercapacitor.

Journal ArticleDOI
TL;DR: In this article, the physical and chemical characteristics of arhar stalk activated carbon scanning electron microscopic, x ray diffraction, thermogravimetric analysis, fourier transform analysis and pore size distribution analysis were performed.

Journal ArticleDOI
06 Jan 2021-Polymer
TL;DR: In this paper, the phase change materials (PCM) are used for the storage of latent thermal energy (LTES), but their low thermal conductivity values and liquid leakage on the transition phase of process limits their application.

Journal ArticleDOI
TL;DR: In this article, a natural compound-based hydrogel adsorbent was developed to remove diclofenac as a model pharmaceutical from water, and the results revealed that the adsorption tends to be of the monolayer type and homogeneous, as the results were in better accordance with the Langmuir model than the Freundlich model.
Abstract: This work aimed at developing a natural compound-based hydrogel adsorbent to remove diclofenac as a model pharmaceutical from water. First, graphene oxide–chitosan (GO–CTS) and amine graphene oxide–chitosan (AGO–CTS) hydrogel adsorbents were synthesized via a facile mechanical mixing method. The synthesized materials were characterized through Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning and transmission electron microscopy (SEM and TEM), Raman spectroscopy, and thermogravimetric analysis (TGA) techniques. In the second stage, adsorption experiments were conducted to determine the best GO to CTS ratio and find the optimized adsorption parameters, including the initial drug concentration, adsorbent dosage, pH, and temperature. The results showed that the optimal GO to CTS mass ratio is 2 : 5 and thus the same ratio was selected as the AGO to CTS mass ratio to understand the effect of amine-functionalization on removal efficiency. The optimal adsorption parameters were determined to be pH of 5, Ci of 100 ppm and dosage of 1.5 g L−1, where 90.42% and 97.06% removal was achieved for optimal GO–CTS and AGO–CTS hydrogel adsorbents, respectively. Langmuir and Freundlich isotherms models were employed to investigate the adsorption behavior of diclofenac onto the synthesized hydrogels. The results revealed that the adsorption tends to be of the monolayer type and homogeneous, as the results were in better accordance with the Langmuir model than the Freundlich model. The thermodynamics of adsorption demonstrated that the adsorption is exothermic, exhibiting higher removal efficiency at lower temperatures. Furthermore, Gibb's free energy change of adsorption (ΔG) suggested that the adsorption is spontaneous, being more spontaneous for AGO–CTS than GO–CTS hydrogels. Finally, the regeneration ability of the hydrogel adsorbents was studied in five consecutive cycles. The adsorbent maintained its efficiency at a relatively high level for three cycles but a considerable decrease was observed between the third and the fourth cycle, indicating that the hydrogels were recoverable for three cycles.

Journal ArticleDOI
01 Jun 2021
TL;DR: In this article, the photocatalytic activities of g-C3N4/TiO2 nanocomposites to remove fluoride under simulated visible light were evaluated, and the results showed that the fluoride removal rate of the prepared g-c3n4/tiO2 was about three times higher than pure g-n4 due to the rapid charge transfer and the efficient separation of photogenerated electron-hole pairs in heterojunctions between g-nc3n 4 and TiO2.
Abstract: As a highly active photocatalyst, g-C3N4/TiO2 heterojunction nanocomposites were in situ synthesized by hydro-thermal method and calcination using melamine as precursors. The morphology and chemical structure of the prepared photocatalysts were characterized by X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), SEM, UV-vis, and photoluminescence analysis (PLA). At last, the photocatalytic activities of g-C3N4/TiO2 nanocomposites to remove fluoride under simulated visible light were evaluated. Results showed that the fluoride removal rate of the prepared g-C3N4/TiO2 was about three times than pure g-C3N4 due to the rapid charge transfer and the efficient separation of photogenerated electron-hole pairs in heterojunctions between g-C3N4 and TiO2. Heterojunction g-C3N4/TiO2 display the excellent fluoride removal rate due to the rapid charge transfer and efficient separation of electron-hole pairs.

Journal ArticleDOI
TL;DR: In this paper, a facile and green synthesis of carbon quantum dots (C-dots) from dill leaves by a single-step hydrothermal method was presented, which could serve as initiators for polymerization.
Abstract: The current work presents a facile and green synthesis of carbon quantum dots (C-dots), which could serve as initiators for polymerization. Herein, C-dots have been synthesized from an easily available green herb, dill leaves, by a single-step hydrothermal method. These C-dots were efficiently utilized as initiators for the photopolymerization of the polymer poly(norepinephrine) (PNE) for the first time. The photopolymerization is discussed by a factorial design, and the optimized synthesis conditions were evaluated by a third-order regression model of three reaction parameters: monomer concentration, C-dots concentration, and UV exposure time. The sign convention of the factorial design mode indicated that monomer concentration and time of exposure are the most important factors for polymerization. The photopolymerized poly(norepinephrine) was extensively studied using Fourier transform infrared (FTIR) analysis, X-ray photoelectron spectroscopy (XPS), mass spectra, scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle measurement, and thermogravimetric analysis (TGA). UV-assisted deposition of PNE on six different types of substrates was performed, and their water contact angle and surface morphology were studied to evaluate the coating. This UV-triggered polymerization technique was further applied to fabricate sandwich-like composite catalyst MXene/poly(norepinephrine)/copper nanoparticles. This catalyst displayed good performance in the reduction of 4-NP (4-nitrophenol) at ambient temperature, and the first-order rate constant of the catalysis was 9.39 × 10-3 s-1. The reusability of the catalyst was evaluated in terms of the conversion factor. After 10 catalytic cycles, the conversion to catalyze 4-NP was still greater than 91%. The catalytic performance was also evaluated in the continuous flow condition through a membrane, fabricated from a cellulose filter paper coated with MXene/poly(norepinephrine)/copper nanoparticles. This composite catalyst not only offers a practical mode for the catalytic reaction of MXene-based materials but also lays down the foundation for the development of new catalysts.

Journal ArticleDOI
TL;DR: In this paper, the non-isothermal oxidation behavior of (Hf-Ta-Zr-Nb) high entropy carbide powders was compared and studied from room temperature to 1300°C using thermogravimetric analysis and differential scanning calorimetry.

Journal ArticleDOI
TL;DR: In this paper, a composite based on gelatin recovered from chromium tanned leather waste and carbon nanotubes showed an adsorption capacity of around 20.57 µm/g−1.
Abstract: Diclofenac is an emerging contaminant belonging to the class of pharmaceutical and personal care products, and its presence in drinking water has been reported in several studies nowadays. The adsorption technique has been highlighted due to its operational simplicity, removal efficiency, and low cost, allowing the use of materials of residual origin. Gelatin has favorable characteristics for the production of adsorbent composites, and it can also be obtained from solid wastes from the tannery industry. Thus, this work aimed to produce composite beads based on gelatin recovered from leather wastes tanned with chromium(III) and the addition of carbon nanotubes, to remove diclofenac sodium. For comparison purposes, a composite based on commercial gelatin and carbon nanotubes was also produced. The composite beads were produced using the drip emulsification method. Equilibrium and kinetic tests were performed, and the materials were characterized by Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), Fourier Transform Infrared (FTIR) Spectroscopy, X-ray diffraction (XRD), Point of zero charge (pHpzc), and Swelling and Water retention capacities. The composite based on gelatin recovered from chromium tanned leather waste and carbon nanotubes showed an adsorption capacity of around 20.57 mg g−1, close to the estimated value for commercial gelatin and carbon nanotubes, that was 26.97 mg g−1. The Freundlich model showed a better fit to the experimental equilibrium data. In adsorption kinetics, the Pseudo-second order model better described the kinetic behavior of removing diclofenac sodium by composite beads.