scholarly journals Characterization and photocatalytic activity of ZnO nanoflowers synthesized using Bridelia retusa leaf extract

2021 ◽  
Author(s):  
Ramesh Vinayagam ◽  
Shraddha Pai ◽  
Thivaharan Varadavenkatesan ◽  
Arivalagan Pugazhendhi ◽  
Raja Selvaraj
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Leaf Extract ◽  
Solar Irradiation ◽  
Bandgap Energy ◽  
Absorption Bands ◽  
First Order Kinetics ◽  
Bet Analysis ◽  
Bridelia Retusa

AbstractIn the current work, the leaf extract of Bridelia retusa was used for the first time to synthesize zinc oxide nanoparticles (ZnONPs). A zinc nanoparticle-specific 364-nm peak was discerned via UV–Vis studies with a typical bandgap energy of 3.41 eV. FE-SEM micrographs revealed flower-shaped structure of the ZnONPs. EDS analysis corroborated the presence of zinc and oxygen. XRD spectrum established the wurtzite structure, sized at 11.06 nm. The mesoporous texture (4.89 nm) of the nanoparticles was deduced from BET analysis, proving a higher specific surface area than commercial ZnONPs. FTIR spectroscopy resulted in absorption bands typical for ZnONPs. Within a span of 165 min, under solar irradiation, the ZnONPs facilitated the photocatalytic degradation of Rhodamine B dye upto 94.74%. Exhibiting pseudo-first-order kinetics, the process had a degradation constant of 0.0109 min−1. It was concluded that numerous factors led to the high degradation efficiency. High values of bandgap energy and specific surface area, along with the mesoporous and crystalline nature of the ZnONPs led to the observed effect. The ZnONPs were also stabilized by the phytochemicals in the B. retusa leaves. The study is thus able to successfully demonstrate the huge potential in the field of environmental nanoremediation. The viability of using ZnONPs as solar photocatalysts for treating dye-laden industrial wastewater was thus attested.

scholarly journals Tuning the Morphological Properties of Cellulose Aerogels: An Investigation of Salt-Mediated Preparation

2021 ◽  
Author(s):  
Prakash Parajuli ◽  
Sanjit Acharya ◽  
Julia Shamshina ◽  
Noureddine Abidi
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Earth Metal ◽  
Morphological Properties ◽  
Cellulose Solution ◽  
Bet Analysis ◽  
Sol Gel Transition ◽  
Gel Transition

Abstract In this study, alkali and alkaline earth metal chlorides with different cationic radii (LiCl, NaCl, and KCl, MgCl2, and CaCl2) were used to gain insight into the behavior of cellulose solutions in the presence of salts. The specific focus of the study was evaluation of the effect of salts’ addition on the sol-gel transition of the cellulose solutions and on their ability to form monoliths, as well as evaluation of the morphology (e.g., specific surface area, pore characteristics, and microstructure) of aerocelluloses prepared from these solutions. The effect of the salt addition on the sol-gel transition of cellulose solutions was studied using rheology, and morphology of resultant aerogels was evaluated by Scanning Electron Microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis, while the salt influence on the aerocelluloses’ crystalline structure and thermal stability was evaluated using powder X-Ray Diffraction (pXRD) and Thermogravimetric Analysis (TGA), respectively. The study revealed that the effect of salts’ addition was dependent on the component ions and their concentration. The addition of salts in the amount below certain concentration limit significantly improved the ability of the cellulose solutions to form monoliths and reduced the sol-gel transition time. Salts of lower cationic radii had a greater effect on gelation. However, excessive amount of salts resulted in the formation of fragile monoliths or no formation of gels at all. Analysis of surface morphology demonstrated that the addition of salts resulted in a significant increase in porosity and specific surface area, with salts of lower cationic radii leading to aerogels with much larger (~1.5 and 1.6-fold for LiCl and MgCl2, respectively) specific surface area compared to aerocelluloses prepared with no added salt. Thus, by adding the appropriate salt into the cellulose solution prior to gelation, the properties of aerocelluloses that control material’s performance (specific surface area, density, and porosity) could be tailored for a specific application.

Microstructural and porosimetry analysis of Ag-TiO2intercalated kaolin and diatomite as nanocomposite ceramic materials

Clay Minerals ◽  
2018 ◽  
Vol 53 (4) ◽  
pp. 665-674 ◽  
Author(s):  
Emmanuel Ajenifuja ◽  
Abimbola P.I. Popoola ◽  
Kabir O. Oyedotun ◽  
Olawale Popoola
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Ceramic Materials ◽  
Mineral Particle ◽  
Scanning Calorimetry ◽  
Sintered Ceramic ◽  
Morphological Studies ◽  
Bet Specific Surface Area ◽  
Bet Analysis

ABSTRACTKaolin and diatomite are abundant and widely available geological materials that may immobilize or stabilize functional chemical species on their surfaces for various applications. Acid-treated kaolin and diatomite were intercalated with photocatalyst Ag-TiO2nanoparticles using the sol–gel technique to prepare nanocomposite ceramic materials. The nanocomposites were sintered between 900°C and 1000°C to induce thermal reactions and to enhance nanoparticle–substrate attachment. Chemical and thermal characterizations of the acid-treated materials and intercalated nanocomposites were performed with energy-dispersive X-ray (EDX) analysis and differential scanning calorimetry (DSC), respectively. The Brunauer–Emmett–Teller (BET)-specific surface area and scanning electron microscopy (SEM) were employed for physical and microstructural characterization of the nanocomposites, respectively. Morphological studies revealed a uniform distribution of Ag-TiO2nanocrystallites in pores and on mineral particle surfaces. The BET analysis showed remarkable surface and grain modification by sintering. Decreases in the BET-specific surface area were observed for the sintered ceramic nanocomposite, Ag-TiO2-kaolin (20.244 to 5.446 m2/g) and Ag-TiO2-diatomite (19.582 to 10.148 m2/g).

Photocatalytic Efficiency for Dye Decolorization of the UV/TiO2, UV/TiO2 + In2O3 and UV/TiO2-In2O3 Systems

2013 ◽  
Vol 831 ◽  
pp. 263-266
Author(s):  
Chung Hsin Wu ◽  
Chao Yin Kuo ◽  
Chih Hao Lai ◽  
Wei Yang Chung
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Dye Decolorization ◽  
X Ray Diffraction ◽  
First Order ◽  
First Order Kinetics ◽  
Vis Spectroscopy ◽  
Reactive Red 2

This study explored the decolorization of C.I. Reactive Red 2 (RR2) by the ultraviolet (UV)/TiO2, UV/TiO2 + In2O3, and UV/TiO2-In2O3 systems. The TiO2-In2O3 was generated by the sol-gel method and TiO2 + In2O3 was created by mixing TiO2 and In2O3 powders. The surface properties of TiO2, In2O3, and TiO2-In2O3 were analyzed by X-ray diffraction, a specific surface area analyzer, UV-vis spectroscopy, and scanning electron microscopy. The specific surface area of TiO2, In2O3, and TiO2-In2O3 was 29.5, 44.6, and 35.7 m2/g, respectively; additionally, the band gap of TiO2, In2O3, and TiO2-In2O3 was 2.95, 2.64, and 2.91 eV; respectively. The decolorization rate constant fit pseudo-first-order kinetics and that of the UV/TiO2, UV/TiO2 + In2O3, and UV/TiO2-In2O3 systems was 0.0023, 0.0031, and 0.0072 min-1; respectively.

scholarly journals Simultaneous deposition of Au nanoparticles during flame synthesis of TiO2 and SiO2

2003 ◽  
Vol 18 (1) ◽  
pp. 115-120 ◽  
Author(s):  
L. Mädler ◽  
W. J. Stark ◽  
S. E. Pratsinis
Keyword(s):  
Metal Oxide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Au Nanoparticles ◽  
Visible Region ◽  
Gold Deposits ◽  
Absorption Bands ◽  
Oxide Support ◽  
Metal Oxide Support

Nanostructured gold/titania and gold/silica particles with up to 4 wt% Au were made by a single-step process in a spray flame reactor. Gold(III)-chloride hydrate and titania- or silica-based metalorganic precursors were mixed in a liquid fuel solution, keeping concentrations in the flame and overall combustion enthalpy constant. The powders were characterized by x-ray diffraction, transmission electron microscopy, Brunauer–Emmett–Teller, and ultraviolet–visible analysis. The titania or silica specific surface area and the crystalline structure of titania were not affected by the presence of gold in the flame. Furthermore the size of the gold deposits was independent of the metal oxide support (TiO2 or SiO2) and its specific surface area (100 and 320 m2/g, respectively). The gold nanoparticles were nonagglomerated, spherical, mostly single crystalline, and well dispersed on the metal oxide support. Depending on the Au weight fraction (1, 2, and 4 wt%) the Au nanoparticles' mass mean diameter was 3, 7, and 15 nm, respectively, on both titania and silica. The particles showed surface plasmon absorption bands in the ultraviolet–visible region, which is typical for nano-sized gold. This absorption band was red shifted in the case of the titania support, while no shift occurred with the silica support.

scholarly journals Combination of mesoporous titanium dioxide with MoS2 nanosheets for high photocatalytic activity

2017 ◽  
Vol 19 (2) ◽  
pp. 56-60 ◽  
Author(s):  
Loghman Karimi
Keyword(s):  
Electron Microscopy ◽  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Dye Degradation ◽  
Hydrothermal Process ◽  
Bet Analysis ◽  
Mesoporous Titanium Dioxide

Abstract This study presents a facile approach for the preparation of MoS2 nanosheet decorated by porous titanium dioxide with effective photocatalytic activity. Mesoporous titanium dioxide nanostructures first synthesized by a hydrothermal process using titanium (III) chloride and then the MoS2/TiO2 were prepared through mixing of MoS2 nanosheet with mesoporous titanium dioxide under ultrasonic irradiation. The synthesized nanocomposite was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), and Brunauer-Emmett-Teller (BET) analysis. The results showed that the nanocomposite has mesoporous structure with specific surface area of 176.4 m2/g and pore diameter of 20 nm. The as-prepared MoS2/TiO2 nanocomposites exhibited outstanding photocatalytic activity for dye degradation under sunlight irradiation, which could be attributed to synergistic effect between the molybdenum disulfide nanosheet and mesoporous titanium dioxide. The photocatalytic performance achieved is about 2.2 times higher than that of mesoporous TiO2 alone. It is believed that the extended light absorption ability and the large specific surface area of the 2D MoS2 nanosheets in the nanocomposite, leading to the enhanced photocatalytic degradation activity.

Sol-gel Synthesis of a Novel χSm2Ti2O7/HZSM-5 Composite Photocatalyst for the Promoted Activity on RBR X-3B Degradation

2017 ◽  
Vol 14 (1) ◽  
pp. 17-25
Author(s):  
Wenjie Zhang ◽  
Jiao Yang ◽  
Ling Du
Keyword(s):  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
Bandgap Energy ◽  
Powder Materials ◽  
Sol Gel Synthesis ◽  
Adsorption Desorption

Background: Pyrochloro structured Sm2Ti2O7 has photocatalytic activity on degradation of organic substances and on hydrogen evolution from water. Powder materials usually encounter the obstacle of separating from treated water. HZSM-5 zeolite is a kind of porous structured material with large surface area. Its role as a support for Sm2Ti2O7 is interesting. Methods: The supported Sm2Ti2O7 was synthesized using sol-gel method. The composite χSm2Ti2O7/HZSM-5 was characterized by XRD, SEM, TEM, FT-IR/FIR, UV-Vis DRS, N2 adsorption- desorption and XPS measurements. Photocatalytic degradation of Reactive Brilliant Red X-3B (RBR X-3B) was measured to evaluate the activity of the composite. Results: Sm2Ti2O7 is in the pyrochlore phase after loading on the surface of HZSM-5 zeolite. The crystal cell of pyrochlore Sm2Ti2O7 continuously expanses with decreasing Sm2Ti2O7 loading content in the composite. Bandgap energy of Sm2Ti2O7 is enlarged after supporting. The specific surface area of Sm2Ti2O7 was enlarged from 9.8 m2/g to 93 m2/g after loading. Both of the adsorption capacity and photocatalytic activity of the χSm2Ti2O7/HZSM-5 are greater than those of pure Sm2Ti2O7. After 120 min of irradiation, 73.1% of the initial RBR X-3B molecules are decomposed on 70%Sm2Ti2O7/HZSM-5, and only 27.7% of the dye is decomposed on the bare Sm2Ti2O7. Conclusion: Sm2Ti2O7 crystal growth is constrained after loading due to dispersion of Sm2Ti2O7 on the surface of HZSM-5. The specific surface area of Sm2Ti2O7 is significantly enlarged after loading. All the supported samples have greatly enhanced photocatalytic activity as compared to the bare Sm2Ti2O7.

Synthesis, Characterisation, and Photocatalytic Behaviour of Mesoporous ZnS Nanoparticles Prepared Using By-Product Templating

2017 ◽  
Vol 70 (10) ◽  
pp. 1099 ◽  
Author(s):  
Hosein B. Motejadded Emrooz ◽  
Ali R. Rahmani ◽  
Francisco J. Gotor
Keyword(s):  
Electron Microscopy ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Diffuse Reflectance Spectroscopy ◽  
High Surface ◽  
Ultrasonic Waves ◽  
Soft Template ◽  
Bandgap Energy ◽  
Zns Nanoparticles

High surface area mesoporous ZnS nanoparticles (MZN) were obtained with the aid of the by-product of the synthesising reaction. This by-product, namely NaNO3, can be considered as a soft template responsible for the formation of pores. Ethanol and water were chosen as the synthesis media. Ultrasonic waves were used as an accelerator for the synthesis of MZNs. Photocatalytic activities of the synthesised samples for the degradation of methylene blue (MB) were investigated under ultraviolet irradiation. Synthesised specimens were characterised using field emission scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, diffuse reflectance spectroscopy, N2-physisorption, and FT-IR spectroscopy. Results indicated that the synthesis media has a pronounced effect on the surface properties of the final porous particles by several mechanisms. The specific surface area of the MZN samples synthesised in water and ethanol were determined to be 53 and 201 m2 g−1, respectively. The difference in the specific surface area was attributed to the weak solvation of S2− ions (Na2S·5H2O in ethanol) and also to the by-product of the synthesis reaction. The photocatalytic behaviour of the mesoporous ZnS nanoparticles synthesised in these two media were investigated and the results have been interpreted with the aid of effective surface area, pore volume, and bandgap energy of the specimens.

Highly Efficient Photodegradation of MO Dye by TiO2 Nanoparticles

2014 ◽  
Vol 989-994 ◽  
pp. 527-530
Author(s):  
Xin Zuo Fang ◽  
Li Sheng Gao
Keyword(s):  
Crystal Structure ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Small Diameter ◽  
Solar Irradiation ◽  
Solar Light ◽  
Thermal Method ◽  
Highly Efficient ◽  
Good Dispersion

use the sol-thermal method to synthesis nanoparticle TiO2 which is well developed, small diameter and good dispersion. XRD and BET methods were used to analyze the crystal structure and specific surface area. Under nature solar light, the photodegradation activity of TiO2is tested. The results show that the TiO2sample displayed better photodegradation activity than P25 under solar irradiation.

scholarly journals Modificação das propriedades da poliamida 12 pela incorporação de carbonato de cálcio nanoparticulado

2020 ◽  
Author(s):  
◽  
R. M. S. Teotonio
Keyword(s):  
Impact Strength ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Flexural Modulus ◽  
Mechanical And Thermal Properties ◽  
Scanning Calorimetry ◽  
Crystallinity Degree ◽  
Bet Analysis ◽  
The Matrix

Polyamide 12 (PA12) was modified by incorporating calcium carbonate nanoparticles (NPCC) to analyze the effect of the filler content on the mechanical and thermal properties of the final nanocomposites. Compositions containing 0.1, 0.2, 0.5, 1, 5 and 10 wt% of Socal 312 and 10 wt% of Socal U1S2 were analyzed. Furthermore, extruded and non-extruded PA12 were compared. NPCC was characterized through BET analysis (Brunauer, Emmett and Teller), which confirmed that Socal 312 had a specific surface area superior to Socal U1S2. Scanning electron microscopy revealed a tendency of the particles to agglomerate at 1 wt% NPCC and higher. However, all samples showed good distribution of the filler throughout the matrix. Differential Scanning Calorimetry (DSC) analyses did not show differences in the melting temperature of the compositions. Crystallization temperature tends to increase as the amount of filler in the matrix increases. Crystallinity degree showed differences only when comparing extruded and non-extruded PA12, the same occurs with Socal 312 in relation to Socal U1S2 containing 10 wt% of filler. Thermogravimetric analysis (TGA) showed that for contents from 0.5 wt% NPCC, increasing NPCC content reduces the thermal stability of the material. Muffle calcination tests confirmed the residues content obtained with TGA at 5 wt% NPCC higher, and evidenced good distribution of the filler along the specimen. Tensile and flexural strength and tensile and flexural modulus started increasing at 1 wt% NPCC and HDT started increasing at 0.2 wt% NPCC, showing the reinforcing effect of nanofiller and the increase in stiffness of the materials. Impact strength at 23 °C decreased at 0.5 wt% NPCC. Impact strength at -40 °C reduced only with addition of 10 wt% NPCC. Strain at break, toughness and impact strength at 23 °C showed reduction in extruded PA12 when compared to non-extruded PA12, possibly because extrusion favors the increase in crystallinity, as verified in the DSC analysis. Socal U1S2 also showed differences in relation to Socal 312 in strain at break, flexural modulus and HDT, probably due to its lower specific surface area in relation to Socal 312. Therefore, the incorporation of 1 wt% NPCC in PA12, already allows to obtain a nanocomposite with greater mechanical strength compared to neat PA12, which can be a feasible alternative for applications where an increase in mechanical properties is desired

Preparation of Fe/γ-Al2O3 Catalyst by Ultrasonic Infiltration and Catalytic Degradation of Formaldehyde Wastewater

2012 ◽  
Vol 518-523 ◽  
pp. 3053-3056
Author(s):  
Dan Wu ◽  
Xian Peng Zheng ◽  
Yan Li ◽  
Qin Wei
Keyword(s):  
Specific Surface ◽  
Catalytic Oxidation ◽  
Surface Area ◽  
Specific Surface Area ◽  
Energy Dispersive Spectrometer ◽  
Chemical Oxidation ◽  
Catalytic Degradation ◽  
X Ray Diffraction ◽  
Bet Analysis

γ-Al2O3 was used as carrier and Fe/γ-Al2O3 catalyst were prepared by wet impregnation and ultrasonic infiltration method and characterized by specific surface area and pore distribution (BET), scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and x-ray diffraction (XRD). Specific surface area of Fe/γ-Al2O3 catalyst was 224.93m2/g from BET analysis. Active component of catalyst was attached on the surface of carrier from the characterization of SEM and EDS. The prepared catalyst was used for the catalytic degradation of formaldehyde wastewater. The results indicated that the efficiency of H2O2/Fe/γ-Al2O3 catalytic oxidation was better than Fe/γ-Al2O3 catalytic oxidation and H2O2chemical oxidation.

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