scholarly journals Improving Thermal Stability and Hydrophobicity of Rutile-TiO2 Nanoparticles for Oil-Impregnated Paper Application

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7964
Author(s):  
Mohammed Mahmood Katun ◽  
Rudo Kadzutu-Sithole ◽  
Nosipho Moloto ◽  
Cuthbert Nyamupangedengu ◽  
Chandima Gomes

Thermal stress and moisture absorption can cause a synergetic negative impact on kraft paper. Among various approaches for improving the dielectric properties of kraft paper, nanotechnology has had promising results. However, the hydrophilicity of most metal oxide nanoparticles renders nanomodified kraft paper more vulnerable to thermal stress and moisture, thereby inducing degradation. In nanomodified kraft paper research, the use of TiO2 nanoparticles has yielded the most promising results. The major shortfall, however, is the hydrophilicity of TiO2. This work investigated surface modifications of rutile-TiO2 nanoparticles (NPs) for improved hydrophobicity and thermal stability. Rutile-TiO2 NPs is a nontoxic metal oxide that can withstand high temperature and is stable in chemical reactions. Two cases of surfactants were used—alkyl ketene dimer (AKD) and alkenyl succinic anhydride (ASA). The intention was to increase heat resistance and reduce the surface free energy of the rutile-TiO2 NPs. The impacts of the surface modifiers on the rutile-TiO2 NPs were characterised using FT-IR, muffle furnace, analytical weight balance, and TGA. It was discovered that new functional groups were formed on the modified NPs examined through FT-IR spectra. This indicates new chemical bonds, introduced through the surface modification. The unmodified rutile-TiO2 NPs absorbed moisture, increasing their mass by 3.88%, compared with the modified nanoparticles, which released moisture instead. TGA analysis revealed that AKD- and ASA-modified rutile-TiO2 needed higher temperatures than the unmodified rutile-TiO2 to markedly decompose. AKD, however, gave better performance than ASA in that regard. As an example, those modified with 5% AKD sustained a 45% higher temperature than the pure TiO2 nanoparticles. Furthermore, in both cases of the surfactants, the higher the percent of surfactant content was, the more thermally stable the nanoparticles became. This work demonstrates the possibility of fabricating rutile-TiO2 NPs to give improved hydrophobicity and thermal stability for possible dielectric applications such as in kraft paper for power transformer insulation.

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 165
Author(s):  
Sandip Madhukar Deshmukh ◽  
Mohaseen S. Tamboli ◽  
Hamid Shaikh ◽  
Santosh B. Babar ◽  
Dipak P. Hiwarale ◽  
...  

In the present work, we have reported a facile and large-scale synthesis of TiO2 nanoparticles (NPs) through urea-assisted thermal decomposition of titanium oxysulphate. We have successfully synthesized TiO2 NPs by using this effective route with different weight ratios of titanium oxysulphate: urea. The structures and properties of TiO2 NPs were confirmed by scanning electron microscope) (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), fourier transform infrared spectroscopy (FT-IR), ultra violet–visible spectroscopy (UV-vis), and photoluminescence (Pl) techniques. XRD demonstrated that TiO2 NPs holds of anatase crystal phase with crystallizing size 14–19 nm even after heating at 600 °C. TGA, SEM, and TEM images reveal urea’s role, which controls the size, morphology, and aggregation of TiO2 NPs during the thermal decomposition. These TiO2 NPs were employed for photodegradation of Methyl Orange (MO) in the presence of ultraviolet (UV) radiation. An interesting find was that the TiO2 NPs exhibited better photocatalytic activity and excellent recycling stability over several photodegradation cycles. Furthermore, the present method has a great perspective to be used as an efficient method for large-scale synthesis of TiO2 NPs.


Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 94 ◽  
Author(s):  
Laura Corredor ◽  
Maen Husein ◽  
Brij Maini

Recent studies revealed higher polymer flooding performance upon adding metal oxide nanoparticles (NPs) to acrylamide-based polymers during heavy oil recovery. The current study considers the effect of TiO2, Al2O3, in-situ prepared Fe(OH)3 and surface-modified SiO2 NPs on the performance of xanthan gum (XG) solutions to enhance heavy oil recovery. Surface modification of the SiO2 NPs was achieved by chemical grafting with 3-(methacryloyloxy)propyl]trimethoxysilane (MPS) and octyltriethoxysilane (OTES). The nanopolymer sols were characterized by their rheological properties and ζ-potential measurements. The efficiency of the nanopolymer sols in displacing oil was assessed using a linear sand-pack at 25 °C and two salinities (0.3 wt % and 1.0 wt % NaCl). The ζ-potential measurements showed that the NP dispersions in deionized (DI) water are unstable, but their colloidal stability improved in presence of XG. The addition of unmodified and modified SiO2 NPs increased the viscosity of the XG solution at all salinities. However, the high XG adsorption onto the surface of Fe(OH)3, Al2O3, and TiO2 NPs reduced the viscosity of the XG solution. Also, the NPs increased the cumulative oil recovery between 3% and 9%, and between 1% and 5% at 0 wt % and 0.3 wt % NaCl, respectively. At 1.0 wt % NaCl, the NPs reduced oil recovery by XG solution between 5% and 12%, except for Fe(OH)3 and TiO2 NPs. These NPs increased the oil recovery between 2% and 3% by virtue of reduced polymer adsorption caused by the alkalinity of the Fe(OH)3 and TiO2 nanopolymer sols.


Author(s):  
Jassim Mohamed Hamed AL-Kurdhani ◽  
Huajun Wang ◽  
Taha Seham Ismail

Two important types of metal oxide nanoparticle catalysts Copper (II) oxide (CuO) and Cerium oxide (CeO2) are prepared by a suitable method which was traditional precipitation (PT) method at calcination temperature of 400oC for 5h and used for the synthesis of glycerol carbonate GC (C4H6O4) from the direct reaction by the carbonylation of Glycerol GL (C3H8O3) with Carbone Dioxide. The precipitation (PT) was an important route for the preparation of nanoparticles catalyst. The effects of performance of (CuO and CeO2) nanoparticle catalysts on the conversion of glycerol GL, yield of glycerol carbonate GC, selectivity of glycerol carbonate are researched. XRD, XPS, BET, FT-IR, CO2-TPD, H2-TPR are used for the characterization of the prepared catalysts. Comparing the optimal performance between them under reaction conditions were 150 oC, 4MPa (40 bar.), 5h, and both CuO and CeO2 catalyst amount 37.6 % (based on ratio of glycerol weight) by using 2-pyridinecarbonitrate (C6H4N2) as dehydrating agent and dimethylformamide (DMF), (C3H7NO) as solvent. The glycerol conversion (XGL), glycerol carbonate yield (YGC) and glycerol carbonate selectivity (SGC) over 0.7g CuO are 57.151%, 47.524%, and 83.156%, respectively, and glycerol carbonate yield over 0.7 CeO2 is 36.2185% or 35.076%, and the yield of GC could reach as high as 78.234% over 1.73g CeO2, the both catalysts could be easily regenerated by washing with methanol and water after a reaction and then dried at 60 oC overnight after that calcination at 400 oC for 5h without loss of activity after five recycling times, In addition to, the (ICP- MS) results confirmed that the leaching of CuO and CeO2 was below the detection limit.


2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Mohamed E. I. Badawy ◽  
Mahmoud A. M. El-Nouby ◽  
Abd El-Salam M. Marei

The present study aims to prepare two new types of chitosan-metal oxide nanoparticles (Ch-MO NPs), namely, chitosan-copper oxide nanoparticles (Ch-CuO NPs) and chitosan-zinc oxide nanoparticles (Ch-ZnO NPs), using sol-gel precipitation mechanism, and test them new as adsorbent materials for extraction and clean-up of different pesticides from water. The design of core-shell was implemented by metal oxide core with chitosan as a hard shell after crosslinking mechanism by glutaraldehyde and then epichlorohydrin. The characterizations of the prepared nanoparticles were investigated using Fourier transform infrared spectrometry (FT-IR), zeta potential, scanning electron microscopy (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD). FT-IR confirmed the interaction between chitosan, metal oxide, and crosslinking mechanism. SEM and TEM explained that the nanoparticles have a spherical morphology and nanosize of 93.74 and 97.95 nm for Ch-CuO NPs and Ch-ZnO NPs, respectively. Factorial experimental design was applied to study the effect of pH, concentration of pesticide, agitation time, and temperature on the efficiency of adsorption of pesticides from water samples. The results indicated that optimum conditions were pH of 7, temperature of 25°C, and agitation time of 25 min. The SPE cartridges were then packed with Ch-MO NPs, and seven pesticides of abamectin, diazinon, fenamiphos, imidacloprid, lambda-cyhalothrin, methomyl, and thiophanate-methyl were extracted from water samples and determined by HPLC. The extraction efficiency of Ch-ZnO NPs was higher than Ch-CuO NPs, but both removed a larger amount of most of tested pesticides than the standard ODS cartridge (C18). The results showed that this method achieves rapid and simple extraction in small quantities of adsorbents (Ch-MO NPs) and solvents. In addition, the method is highly sensitive to pesticides and has a high recovery rate.


Change in lifestyle of humans in this present generation with huge dependence on packaging materials has encouraged several studies on development of new variety of packaging materials. Emphasis on replacement of existing non-biodegradable packaging materials with biodegradable materials paved the way for the use of biopolymers. Lack of properties, such as thermal stability and mechanical strength in biopolymers led to the development of biopolymer nanocomposites by adding metal/metal oxide nanoparticles as fillers into the biopolymers. Metal/metal oxide nanoparticles improve mechanical/tensile strength, thermal stability as well as antimicrobial properties of the binding and receiving polymer matrix. Bio-mediated synthesis of metal/metal oxide nanoparticles result in the development of novel packaging materials at a low cost and without releasing hazardous wastes into the environments. Novel packaging materials with metal/metal oxide nanoparticles as additives are capable of increasing the shelf life of food, in certain cases they act as indicators of quality food inside the package. Summarily, this present chapter focuses on bio-mediated synthesis of various metal/metal oxide nanoparticles and their applications in food packaging.


2018 ◽  
Vol 54 (1A) ◽  
pp. 292
Author(s):  
Long Giang Bach

This paper presents the preparation of polystyrene functionalized TiO2 nanoparticles using the reversible addition fragmentation chain transfer (RAFT) polymerization. The surface of TiO2 NPs with an average particle size of about 5 nm was modified by S-benzyl S’-trimethoxysilylpropyltrithiocarbonate in order to obtain the RAFT agent functionalized TiO2 NPs (TiO2-RAFT). Subsequently, styrene was radically polymerized through the immobilized RAFT agent on the silica surface, in the presence of 2,2’-azobisisobutylnitrile (AIBN) as an initiator, to achieve the TiO2-g-PS nanocomposite. The characteristics of the as-synthesized nanocomposite were determined using FT-IR, EDX, XPS, TGA, XRD, TEM and SEM analyses.


Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1076 ◽  
Author(s):  
Pedro Rivero ◽  
Juan Maeztu ◽  
Calos Berlanga ◽  
Adrian Miguel ◽  
José Palacio ◽  
...  

In this work, layers of a sol-gel hybrid matrix doped with metal oxide nanoparticles (TiO2 NPs) have been deposited on flat samples of AA6061-T6 aluminum alloy using the dip-coating technique, with the aim of obtaining coatings with better anti-corrosive and hydrophobic properties. Two different organic modified silica alkoxides, namely 3-(glycidyloxypropyl)trimethoxysilane (GPTMS) and methyltriethoxysilane (MTEOS), have been used for an adequate entrapment of the metal oxide nanoparticles. In addition, a fluorinated metal-alkoxide precursor has also been added to the hybrid matrix in order to improve the hydrophobic behavior. The experimental results corroborate that the presence of these TiO2 NPs play an important role in the development of the sol-gel hybrid coatings. The water contact angle (WCA) measurements, as well as pencil hardness tests indicate that TiO2 NPs make a considerable increase in the resultant hydrophobicity possible, with better mechanical properties of the coatings. The coating thickness has been measured by cross-section scanning electron microscopy (SEM). In addition, a glow discharge optical emission spectroscopy (GD-OES) analysis has been carried out in order to corroborate the adequate entrapment of the TiO2 NPs into the sol-gel coatings. Finally, potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) have been performed in order to evaluate the corrosion resistance of the coatings. All the results provide insights into the efficacy of the developed sol-gel hybrid coatings for anticorrosive purposes with good mechanical properties.


2020 ◽  
Vol 10 (17) ◽  
pp. 5864
Author(s):  
Lucía Blanco-Covián ◽  
José Ramón Campello-García ◽  
María Carmen Blanco-López ◽  
Manuel Miranda-Martínez

This study explores the potential antibiofouling capacity of coatings based on mixes of poly vinyl alcohol (PVA)-glutaraldehyde (GA) incorporating additions of metal and metal oxide nanoparticles (TiO2, ZnO, CuO, AgNPs and Ag-TiO2NPs). Such a kind of hybrid polymer-nanoparticle mix (PVA/GA/ nanoparticles (NPs)) was uniformly applied by spin coating on the surface of a laboratory raceway and tested in freshwater loaded with green algae communities. The results showed PVA/GA was a convenient carrier for the nanoparticles tested. Image analysis of the coatings showed that Ag-TiO2 nanoparticles exhibited a significant improvement of the antibiofouling effect when compared with that of AgNPs and TiO2-NPs. The effect of the Ag-TiO2 NPs loaded coating about four times better than that of ZnO-NPs. A consistent experimental methodology was developed to test the antibiofouling capacity of the coatings and the hybrid coatings developed have demonstrated promising results as environmentally friendly antibiofouling materials.


2019 ◽  
Vol 6 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Asli Baysal ◽  
Hasan Saygin ◽  
Gul Sirin Ustabasi

Background: The enormous properties of metal oxide nanoparticles make it possible to use these nanoparticles in a wide range of products. As their usage and application continue to expand, environmental health concerns have been raised. In order to understand the behavior and effect of metal oxide nanoparticles in the environment, comprehensive and comparable physicochemical and toxicological data on the environmental matrix are required. However, the behavior and effect of nanoparticles in the real environmental matrix, e.g. sea water, are still unknown. Methods: In this study, the effects of zinc oxide (ZnO) and titanium dioxide (TiO2 ) nanoparticles on the bacteria (gram positive-Bacillus subtilis, Staphylococcus aureus/gram-negative Escherichia coli, and Pseudomonas aeruginosa) in sea water were investigated. Furthermore, to better understand the behavior of the toxicity, surface chemistry, sedimentation, dissolution, particle size, and zeta potential of the nanoparticles dispersed in the sea water matrices were investigated using Fourier-transform infrared spectrometry (FTIR), ultraviolet–visible (UV-VIS) spectrophotometry, graphite furnace atomic absorption spectrometer (GFAAS), and dynamic light scattering (DLS), respectively. Results: The environmental matrix had a significant influence on physicochemical behavior of the tested nanoparticles. Besides, the inhibition of tested bacteria was observed against ZnO and TiO2 nanoparticles in the presence of sea water, while there was no inhibition in the controlled condition. Conclusion: The results demonstrate that surface chemistry with exposure to the sea water can have a significant role on the physicochemical properties of nanoparticles and their toxicity.


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