scholarly journals Organoclay hybrid materials as precursors of porous ZnO/silica-clay heterostructures for photocatalytic applications

2016 ◽  
Vol 7 ◽  
pp. 1971-1982 ◽  
Author(s):  
Marwa Akkari ◽  
Pilar Aranda ◽  
Abdessalem Ben Haj Amara ◽  
Eduardo Ruiz-Hitzky
Keyword(s):  
Zno Nanoparticles ◽  
Organic Dyes ◽  
Water Solution ◽  
Layered Silicate ◽  
Ultrasound Irradiation ◽  
Pharmaceutical Drugs ◽  
Silica Substrate ◽  
Physico Chemical ◽  
Hydrolysis Of ◽  
Photocatalytic Applications

In this study, ZnO/SiO2-clay heterostructures were successfully synthesized by a facile two-step process applied to two types of clays: montmorillonite layered silicate and sepiolite microfibrous clay mineral. In the first step, intermediate silica–organoclay hybrid heterostructures were prepared following a colloidal route based on the controlled hydrolysis of tetramethoxysilane in the presence of the starting organoclay. Later on, pre-formed ZnO nanoparticles (NP) dispersed in 2-propanol were incorporated under ultrasound irradiation to the silica–organoclay hybrid heterostructures dispersed in 2-propanol, and finally, the resulting solids were calcinated to eliminate the organic matter and to produce ZnO nanoparticles (NP) homogeneously assembled to the clay–SiO2 framework. In the case of montmorillonite the resulting materials were identified as delaminated clays of ZnO/SiO2-clay composition, whereas for sepiolite, the resulting heterostructure is constituted by the assembling of ZnO NP to the sepiolite–silica substrate only affecting the external surface of the clay. The structural and morphological features of the prepared heterostructures were characterized by diverse physico-chemical techniques (such as XRD, FTIR, TEM, FE-SEM). The efficiency of these new porous ZnO/SiO2-clay heterostructures as potential photocatalysts in the degradation of organic dyes and the removal of pharmaceutical drugs in water solution was tested using methylene blue and ibuprofen compounds, respectively, as model of pollutants.

scholarly journals Experimental and Physico-Chemical Comparison of ZnO Nanoparticles’ Activity for Photocatalytic Applications in Wastewater Treatment

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 678
Author(s):  
Stefano Alberti ◽  
Irene Basciu ◽  
Marco Vocciante ◽  
Maurizio Ferretti
Keyword(s):  
Wastewater Treatment ◽  
Zno Nanoparticles ◽  
Energy Dispersive Spectrometer ◽  
Chemical Properties ◽  
X Ray Diffraction ◽  
Commercial Sample ◽  
Synthetic Process ◽  
Physico Chemical ◽  
Photocatalytic Applications ◽  
Reflectance Measurements

In this contribution, the photoactivity upon activation by simulated sunlight of zinc oxide (ZnO) obtained from two different synthetic pathways (Acetate and Nitrate) is investigated for water purification. Different reagents and processes were exploited to obtain ZnO nanoparticles. Products have been characterized by means of X-Ray Diffraction, Scanning Electron Microscopy along with Energy Dispersive Spectrometer, Dynamic Light Scattering, and Diffuse Reflectance Measurements, to highlight the different outcomes ascribable to each synthesis. A comparison of characteristics and performances was also carried out with respect to commercial ZnO. Nanoparticles of this semiconductor can be obtained as aggregates with different degrees of purity, porosity, and shape, and their physical-chemical properties have been addressed to the specific use in wastewater treatment, testing their effectiveness on the photocatalytic degradation of methylene blue (MB) as a model pollutant. Excluding the commercial sample, experimental results evidenced a better photocatalytic behavior for the ZnO Nitrate sample annealed at 500 °C, which was found to be pure and stable in water, suggesting that ZnO could be effectively exploited as a heterogeneous photocatalyst for the degradation of emerging pollutants in water, provided that thermal treatment is included in the synthetic process.

scholarly journals Silica Monolith for the Removal of Pollutants from Gas and Aqueous Phases

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1316
Author(s):  
Vanessa Miglio ◽  
Chiara Zaccone ◽  
Chiara Vittoni ◽  
Ilaria Braschi ◽  
Enrico Buscaroli ◽  
...  
Keyword(s):  
Rhodamine B ◽  
Water Solution ◽  
Synthesis Method ◽  
Textural Properties ◽  
Adsorption Properties ◽  
Water Soluble ◽  
Silica Monoliths ◽  
Physico Chemical ◽  
Gaseous Toluene ◽  
Mcm 41

This study focused on the application of mesoporous silica monoliths for the removal of organic pollutants. The physico-chemical textural and surface properties of the monoliths were investigated. The homogeneity of the textural properties along the entire length of the monoliths was assessed, as well as the reproducibility of the synthesis method. The adsorption properties of the monoliths for gaseous toluene, as a model of Volatile Organic Compounds (VOCs), were evaluated and compared to those of a reference meso-structured silica powder (MCM-41) of commercial origin. Silica monoliths adsorbed comparable amounts of toluene with respect to MCM-41, with better performances at low pressure. Finally, considering their potential application in water phase, the adsorption properties of monoliths toward Rhodamine B, selected as a model molecule of water soluble pollutants, were studied together with their stability in water. After 24 h of contact, the silica monoliths were able to adsorb up to the 70% of 1.5 × 10−2 mM Rhodamine B in water solution.

scholarly journals Physico-Chemical Characterization and Antimicrobial Properties of Hybrid Film Based on Saponite and Phloxine B

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 325
Author(s):  
Nitin Chandra teja Dadi ◽  
Matúš Dohál ◽  
Veronika Medvecká ◽  
Juraj Bujdák ◽  
Kamila Koči ◽  
...  
Keyword(s):  
Hybrid Film ◽  
Antimicrobial Properties ◽  
Chemical Characterization ◽  
Layered Silicate ◽  
Contact Angles ◽  
Exchange Capacity ◽  
Resistant Bacteria ◽  
Hybrid Films ◽  
Water Contact ◽  
Physico Chemical

This research was aimed at the preparation of a hybrid film based on a layered silicate saponite (Sap) with the immobilized photosensitizer phloxine B (PhB). Sap was selected because of its high cation exchange capacity, ability to exfoliate into nanolayers, and to modify different surfaces. The X-ray diffraction of the films confirmed the intercalation of both the surfactant and PhB molecules in the Sap film. The photosensitizer retained its photoactivity in the hybrid films, as shown by fluorescence spectra measurements. The water contact angles and the measurement of surface free energy demonstrated the hydrophilic nature of the hybrid films. Antimicrobial effectiveness, assessed by the photodynamic inactivation on hybrid films, was tested against a standard strain and against methicillin-resistant bacteria of Staphylococcus aureus (MRSA). One group of samples was irradiated (green LED light; 2.5 h) and compared to nonirradiated ones. S. aureus strains manifested a reduction in growth from 1-log10 to over 3-log10 compared to the control samples with Sap only, and defects in S. aureus cells were proven by scanning electron microscopy. The results proved the optimal photo-physical properties and anti-MRSA potential of this newly designed hybrid system that reflects recent progress in the modification of surfaces for various medical applications.

scholarly journals Ultrasound-irradiated synthesis of 3-mercaptopropyl trimethoxysilane-modified hydroxyapatite derived from fish-scale residues followed by ultrasound-assisted organic dyes removal

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Phitchan Sricharoen ◽  
Supalak Kongsri ◽  
Chunyapuk Kukusamude ◽  
Yonrapach Areerob ◽  
Prawit Nuengmatcha ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Textile Industry ◽  
Organic Dyes ◽  
Dye Adsorption ◽  
Ultrasound Irradiation ◽  
Coefficient Of Determination ◽  
Fish Scale ◽  
Transmission Electron ◽  
Endothermic Process ◽  
Langmuir Isotherm Model

AbstractWe report a novel method for the synthesis of 3-mercaptopropyl trimethoxysilane-modified hydroxyapatite (FHAP-SH) derived from fish-scale residues by using ultrasound irradiation. Scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy were used for the FHAP-SH characterization. Then, the organic dye adsorption on the FHAP-SH was monitored through an ultrasound process. After the dye removal optimization, significant improvements were observed in the maximum adsorption capacities for Congo Red (CR, 500 mg g−1), Coomassie Brilliant Blue G 250 (CB, 235 mg g−1), and Malachite Green (MG, 625 mg g−1). The adsorption behaviors of these dyes were fitted by using the Langmuir isotherm model with a high coefficient of determination values ranging from 0.9985 to 0.9969. The adsorption of the three dyes onto FHAP-SH was an endothermic process based on the adsorption thermodynamics model, while the adsorption kinetics analysis of the dyes presented a good alignment with the pseudo-second-order kinetics. The FHAP-SH exhibits a remarkably high adsorption capacity, is inexpensive, and fulfills the ecofriendly requirements of dye wastewater treatment, especially in the textile industry.

Breakthrough in hydrolysis of waste biomass by physico-chemical pretreatment processes for efficient anaerobic digestion

Chemosphere ◽  
2022 ◽  
pp. 133617
Author(s):  
Preethi ◽  
Rajesh Banu J ◽  
Sunita Varjani ◽  
Sivashanmugam P ◽  
Vinay Kumar Tyagi ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Waste Biomass ◽  
Chemical Pretreatment ◽  
Physico Chemical ◽  
Hydrolysis Of ◽  
Pretreatment Processes

Ferrite

2021 ◽  
Keyword(s):  
High Frequency ◽  
Biomedical Applications ◽  
Organic Dyes ◽  
High Tech ◽  
Hexagonal Ferrites ◽  
Wastewater Remediation ◽  
Structure Synthesis ◽  
Synthesis Properties ◽  
Photocatalytic Applications ◽  
Classification Structure

Ferrites are highly interesting high-tech materials. The book covers their classification, structure, synthesis, properties and applications. Emphasis is placed an biomedical applications, degradation of organic pollutants, high frequency applications, photocatalytic applications for wastewater remediation, solar cell applications, removal of organic dyes and drugs from aquatic systems, and the synthesis of hexagonal ferrites.

Detailed structural and optical studies of the microwave synthesized β-Bi2O3 nanostructured photocatalysts: Photocatalytic applications on anionic and cationic organic dyes

2021 ◽  
pp. 100629
Author(s):  
Kaviyapriya Kirubanithy ◽  
Jayaraj Santhosh Kumar ◽  
Rosalin Beura ◽  
Thangadurai Paramasivam
Keyword(s):  
Organic Dyes ◽  
Optical Studies ◽  
Photocatalytic Applications

scholarly journals ISOLATION AND ANALYSIS OF STEROIDAL SAPONINS FROM POLYGONATUM ODORATUM (MILL.) DRUCE

2021 ◽  
Vol 55 ◽  
pp. 135-140
Author(s):  
Cristina MOGOSAN ◽  
Ilioara ONIGA ◽  
Mircea TAMAS
Keyword(s):  
Thin Layer ◽  
Acid Hydrolysis ◽  
Thin Layer Chromatography ◽  
Biological Properties ◽  
Steroidal Saponins ◽  
Physico Chemical ◽  
Layer Chromatography ◽  
Hydrolysis Of

We isolated the steroidal saponins from the rhizomes of Polygonatum odoratum (Mill.) Druce with an efficiency of 4.50% which represents 7 fractions identified by thin-layer chromatography (TLC), of which 3 were furostanics and 4 spirostanics. After the acid hydrolysis of the saponins, one aglycone (sapogenine) was identified by TLC. Further, we have determined the physico-chemical and the biological properties of the isolated saponins.

scholarly journals On Photocatalytic Activity of Systems of Titania/(Fe (II, III))-Type in Aqueous Suspensions

2018 ◽  
Vol 17 (6) ◽  
pp. 521-527
Author(s):  
V. A. Gorbunova ◽  
L. M. Sliapniova
Keyword(s):  
Photocatalytic Activity ◽  
Oxidation Reaction ◽  
High Photocatalytic Activity ◽  
Organic Dye ◽  
Iron Ions ◽  
Physico Chemical ◽  
Photocatalytic System ◽  
Initial Suspension ◽  
Hydrolysis Of ◽  
Chemical Water

. The photocatalytic activity of three systems, promising for chemical water purification technologies, was experimentally compared, based on a combination of titanium dioxide/(Fe(II, III)), applying to the model oxidation reaction of methylorange organic dye in an aqueous medium. Herewith the cases of photocatalytic systems were investigated, which are based on: a) titania hydrosol obtained by hydrolysis of titanium isobutylate; b) a similar hydrosol with addition of Fe(III) ions; c) suspension of ilmenite powder based on FeTiO3. As a result of the investigation, the increase of the rate of destruction of methylorange by more than two times was found in the system with the introduction of a small amount of iron ions into initial suspension of the TiO2 hydrosol (at the obtaining a medium with the Fe3+ concentration up to 3.7 × 10–5 M). In the photocatalytic system, based on the suspension of pretreated (with suphation and calcination) ilmenite powder, enough high photocatalytic activity (the degree of methylorange decomposition up to 77 %) was measured but at a higher exposure than for the case of systems based on the TiO2 hydrosol. For the photocatalytic systems of the type being investigated, a possible mechanism of increasing their oxidative activity was briefly considered, which requires an additional physico-chemical analysis.

Lactose-free Dulce de leche: compositional characterization, browning and texture profile

2021 ◽  
pp. 1-5
Author(s):  
Caroline Barroso dos Anjos Pinto ◽  
Isis Rodrigues Toledo Renhe ◽  
Carolina Carvalho Ramos Viana ◽  
Ítalo Tuler Perrone ◽  
Luiz Fernando Cappa de Oliveira ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Chemical Characteristics ◽  
High Demand ◽  
Free Products ◽  
Texture Profile ◽  
Physico Chemical ◽  
Texture Parameters ◽  
Reaction Texture ◽  
Hydrolysis Of ◽  
Compositional Characterization

Abstract Our objective was to elaborate lactose-free Dulce de leche (DL) and evaluate the influence of the hydrolysis of this sugar on the attributes of the products. Fluid milk used was divided into two portions and, in one of them, enzymatic hydrolysis of lactose was carried through. Next, the homogenization of milk was performed at 20 MPa. Four different treatments were studied. The final products were evaluated in relation to their composition and physico-chemical characteristics. The main results show that the homogenized lactose-free DL obtained a higher concentration of free 5-Hydroxymethylfurfural (HMF) (133.77 ± 3.42 μmol l−1). Consequently, browning was more intense due to Maillard Reaction. Texture parameters were higher (1611.00 ± 598.78 g hardness and 19.52 ± 2.46 g gumminess) when compared to the homogenized traditional product (28.45 ± 1.16 μmol l−1 free HMF, 437.17 ± 279.3 g hardness, and 406.20 ± 311.69 g gumminess). Lactose-free products are in high demand by consumers; however, the results of this work highlight the challenges to properly control the browning and the texture parameters of DL.

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