Use of Ca–alginate as a novel support for TiO2 immobilization in methylene blue decolorisation

2009 ◽  
Vol 60 (4) ◽  
pp. 1081-1087 ◽  
Author(s):  
Juliana Q. Albarelli ◽  
Diego T. Santos ◽  
Sharon Murphy ◽  
Michael Oelgemöller
Keyword(s):  
Methylene Blue ◽  
Alginate Bead ◽  
Industrial Process ◽  
Degradation Efficiency ◽  
Great Promise ◽  
Destructive Effect ◽  
Gel Beads ◽  
Tio2 Gel ◽  
Ca Alginate ◽  
Tio2 Immobilization

This study provides a preliminary contribution to the development of an industrial process for the UV/TiO2 water treatment by introducing a novel support for TiO2 immobilization. For the following study, Methylene Blue (MB) was chosen as the model dye to evaluate this novel immobilization system. The results showed that TiO2 immobilized in a Ca–alginate bead retained its photoactivity during all of the experiments and the TiO2-gel beads presented good stability in water for maintaining its shape after several uses. When a proportion of 10% (v/v) of these beads was used, the configuration system demonstrated an improved mass transfer and consequently enhanced degradation efficiency. Experiments were also performed using ‘recycled’ beads. The results showed an increase in the degradation efficiency when the beads were reused, with an eventual ‘self-destructive’ effect. These studies showed great promise regarding the recyclable reagents with a reduction in waste at no greater cost or reduction in efficiency. Therefore, the potential of TiO2-gel beads as a simple and environmentally friendly catalyst for continuous use was developed.

Removal of methylene blue and Lead (II) via PVA/SA double cross-linked network gel beads loaded Fe3O4@KHA nanoparticles

2021 ◽  
Author(s):  
Niu Yuhua ◽  
Han Xingxing ◽  
Song Jie ◽  
Huang Liangxian
Keyword(s):  
Methylene Blue ◽  
Polyvinyl Alcohol ◽  
Sodium Alginate ◽  
Potassium Humate ◽  
Gel Beads ◽  
Ferroferric Oxide ◽  
Double Cross

Novel magnetic gel beads were successfully fabricated via polyvinyl alcohol (PVA) and sodium alginate (SA) double cross-linked network loaded ferroferric oxide@potassium humate (Fe3O4@KHA) nanoparticles. PVA/SA/Fe3O4@KHA gel beads were found to...

Swelling Behavior and Drug Release of Polymer Coated Nano Iron Oxide Embedded Hydroxyapatite

2019 ◽  
Vol 829 ◽  
pp. 108-113
Author(s):  
Yoshiyuki Yokogawa ◽  
Rina Ohkura ◽  
Yoko Inoue ◽  
Atsumasa Shishido ◽  
Ereath Beeran Ansar ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Elevated Temperature ◽  
Ambient Temperature ◽  
Polyelectrolyte Complex ◽  
Elevated Temperatures ◽  
Release Behavior ◽  
Swelling Properties ◽  
Gel Beads ◽  
Calcium Alginate Gel ◽  
Ca Alginate

Spherical calcium-alginate gel beads containing HAIO, iron oxide (IO) nanoparticles embedded on hydroxapatite (HA), were prepared along with and poly (N-isopropylacrylamide) (PNIPAAM) or chitosan. These spheres, HAIO, HAIO-PNIPAAM and HAIO-chitosan spheres, were used as carriers of 5-fluorouracil (5-FU), one of the drugs for cancer chemical therapy, and the 5-FU release behavior in PBS solution was investigated at ambient and elevated temperatures using U-V spectrometry. The amount of the released 5-FU from the HAIO spheres was somewhat higher than that from HAIO-PNIPAAM and HAIO-chitosan spheres at ambient temperature. At elevated temperature, HAIO spheres showed an increase in quantity of released 5-FU. The amount of released 5-FU from HAIO-PNIPAAM spheres was almost the same, and that from HAIO-chitosan spheres was reduced compared to those at ambient temperature. These spheres, HAIO, HAIO-PNIPAAM and HAIO-chitosan spheres, show the similar swelling properties at elevated temperature. However, the combinations of Ca-alginate - PNIPAAM or Ca-alginate - chitosan may produce the different structures, which are core-shell network for HAIO-PNIPAAM spheres and or a polyelectrolyte complex for HAIO-chitosan spheres, leading to a different release behavior of 5-FU.

Treatment of pesticide rinsate towards reuse by photosensitized Fenton-like process

2010 ◽  
Vol 62 (6) ◽  
pp. 1424-1431 ◽  
Author(s):  
W. S. Kuo ◽  
Y. Y. Ho
Keyword(s):  
Molecular Structure ◽  
Molecular Weight ◽  
Methylene Blue ◽  
Hydroxyl Radicals ◽  
Catalytic Effect ◽  
Degradation Efficiency ◽  
Alizarin Red S ◽  
Alizarin Red ◽  
Complete Destruction ◽  
Quinone Structure

A Fenton-like process with combination of dye has been used to enhance the treatment of carbofuran (2,3-dihydro-2,2-dimethylbenzofuran -7-yl methylcarbamate) pesticide rinsate. Results showed that as compared to Fenton-like process, this photosensitization Fenton-like process improved the degradation efficiency of carbofuran rinsate significantly. Among the conditions studied, the optimum dosage for the complete destruction of carbofuran molecular structure was found under a [H2O2]0/[Fe3 + ]0 ratio of 30–35 and a [Dye]0/[Fe3 + ]0 ratio of 2%, respectively, after an irradiance of 500 W/m2 for 20 min. As a result, the COD degradation efficiency of rinsate could be promoted from 37.1 to 61.2% and 66.0% by an addition of methylene blue (MB) and alizarin red S (ARS), respectively. Nevertheless, ARS showed a much more effective acceleration effect on the mineralization and microtoxicity reduction of carbofuran than MB. A mineralization efficiency of 57.2% and a microtoxicity reduction of 90% could be achieved with the addition of ARS. Because of its quinone structure unit, the dye ARS could play a role like hydroquinone to recycle Fe2 +  from Fe3 + , resulting in one more catalytic effect on the reduction of Fe3 +  and thus the mineralization and microtoxicity reduction of carbofuran was greatly promoted in the presence of ARS. In addition, it was found that carbofuran molecules could be decomposed quickly to lower-molecular-weight intermediates and even mineralized by attacking of hydroxyl radicals. Carbofuran was found to be decomposed to carbofuran phenol, 3-oxo carbofuran phenol, and 3-hydroxyl carbofuran phenol initially, and then further be degraded to smaller molecules, such as NO3−, CH3COOH, (COOH)2 and CO2. Accordingly, it was believed that the Fenton-like process along with the aid of a photosensitizer, such as ARS, under an appropriate ratio could be a feasible and potential technology for the treatment of pesticide rinsate.

Synthesis and characterization of anatase TiO2 nanolayer coating on Ni–Cu–Zn ferrite powders for magnetic photocatalyst

2010 ◽  
Vol 25 (1) ◽  
pp. 134-140 ◽  
Author(s):  
Yen-Pei Fu ◽  
Wen-Ku Chang ◽  
Hsin-Chao Wang ◽  
Chung-Wen Liu ◽  
Cheng-Hsiung Lin
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Degradation ◽  
Sol Gel ◽  
Titanium Isopropoxide ◽  
Degradation Efficiency ◽  
Ferrite Powder ◽  
Order Kinetic ◽  
Magnetic Photocatalyst ◽  
The Core ◽  
Zn Ferrite

In the current research, we successfully prepared TiO2/Ni–Cu–Zn ferrite composite powder for magnetic photocatalyst. The core Ni–Cu–Zn ferrite powder was synthesized using the steel pickling liquor and the waste solution of electroplating as the starting materials. The shell TiO2 nanocrystal was prepared by sol-gel hydrolysis precipitation of titanium isopropoxide [Ti(OC3H7)4] on the Ni–Cu–Zn ferrite powder followed by heat treatment. From transmission electron microscopy (TEM) image, the thickness of the titania shell was found to be approximately 5 nm. The core of Ni–Cu–Zn ferrite is spherical or elliptical shape, and the particle size of the core is in the range of 70–110 nm. The magnetic Ni–Cu–Zn ferrite nanopowder is uniformly encapsulated in a titania layer forming core-shell structure of TiO2/Ni–Cu–Zn ferrite powder. The degradation efficiency for methylene blue (MB) increases with magnetic photocatalyst (TiO2/Ni–Cu–Zn ferrite powder) content. When the magnetic photocatalyst content is 0.40 g in 150 mL of MB, the photocatalytic activity reached the largest value. With a further increase in the content of magnetic photocatalyst, the degradation efficiency slightly decreased. This occurs because the ultraviolet (UV) illumination is covered by catalysts, which were suspended in the methylene blue solution and resulted in the inhibition in the photocatalytic reaction. The photocatalytic degradation result for the relationship between MB concentration and illumination revealed a pseudo first-order kinetic model of the degradation with the limiting rate constant of 1.717 mg/L·min and equilibrium adsorption constant 0.0627 L/mg. Furthermore, the Langmuir–Hinshelwood model can be used to describe the degradation reaction, which suggests that the rate-determining step is surface reaction rather than adsorption is in photocatalytic degradation.

scholarly journals Enhanced photocatalytic and biological observations of green synthesized AC, AC/Ag and AC/Ag/TiO2 nanocomposites

2021 ◽  
Author(s):  
M AMALANATHAN ◽  
C. Parvathiraja ◽  
Asma A. Alothman ◽  
Saikh M. Wabaidur ◽  
Mohammad Ataul Islam
Keyword(s):  
Methylene Blue ◽  
Antibacterial Activity ◽  
Activated Carbon ◽  
Electron Microscope ◽  
Active Sites ◽  
Waste Water Treatment ◽  
Degradation Efficiency ◽  
Morphological Properties ◽  
X Ray ◽  
Flower Extract

Abstract In this study, AC/Ag/TiO2 nanocomposite was successfully synthesized by hydrothermal method using jasmine flower extract. The reactions of reduction, stabilization and capping was executed from the biomolecules of jasmine flower extract. The decoration of activated carbon and noble metal to the metal oxide enhanced the properties in all ways. As the modified structural, optical and morphological properties of as prepared nanocomposite was characterized using various techniques such as, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-Visible spectroscopy, Scanning electron microscope (SEM) with Energy dispersive X-ray spectroscopy (EDX), and Transmission electron microscope (TEM). The photocatalytic activities under sunlight were evaluated by the degradation of methylene blue (MB). Antibacterial activity was tested against E-coli and S. aureus. The characterization results show that AC/Ag/TiO2 nanocomposite is crystalline, needle like morphology and highly optically active catalyst. The investigated AC/Ag/TiO2 nanocomposite shows 96% maximum degradation efficiency at the end of 120 minutes undervisible light irradiation. The degradation efficiency and antibacterial activity is readily higher than that of commercial TiO2. The plasmonic support to the activated carbon and titanium nanoparticles creates large surface area, active sites and accelerated the free radical generation. These characteristics demonstrated that the prepared AC/Ag/TiO2 nanocomposite material is highly suitable for the decomposition of methylene blue and waste water treatment.

scholarly journals Microwave Combustion Synthesis, Structural and Morphological Properties of Mg-doped CoFe2O4 Nano-Magnetic Photocatalyst

2019 ◽  
Vol 8 (12S) ◽  
pp. 1072-1075
Keyword(s):  
Methylene Blue ◽  
Degradation Efficiency ◽  
Morphological Properties ◽  
Optimal Conditions ◽  
Magnetic Photocatalyst ◽  
Microwave Assisted ◽  
Microwave Combustion ◽  
Nano Catalyst ◽  
Microwave Assisted Method ◽  
Mg Doped

In the present study, pure and Mg-doped CoFe2O4 nano-magnetic photocatalyst was rapidly prepared based on a microwave-assisted method. Magnetic nano-catalyst are potent heterogeneous photocatalysts for degradation of methylene blue (MB) and promising alternatives to conventional catalysts used in wastewater treatments. Powder XRD, FTIR, HRSEM, EDS, and VSM were performed to identify the structure of Mg-doped CoFe2O4 . The optimal conditions for maximum degradation efficiency were confirmed. The degradation efficiency was also reported to be 87.85% under optimal conditions. Finally, nano-magnetic photocatalyst could be reused for six further runs without remarkable changes in catalytic efficiencies; after six runs, adequate reusability and chemical stability were observed

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