Development of ferrite/metal vanadate composite photocatalysts for organic compounds degradation

การพัฒนาตัวเร่งปฏิกิริยาด้วยแสงของวัสดุผสมเฟอร์ไรต์และโลหะวานาเดตสำหรับการย่อยสลายสารประกอบอินทรีย์

Name: Umaporn Lamdab

Classification :.DDC: 669.96142

LCSH: Organic compounds

LCSH: Photocatalysis

LCSH: Manganese

LCSH: Metals

LCSH: Ferrite

Abstract: In this thesis, we investigated the synthesis, characterization, adsorption and photocatalytic properties of bismuth vanadate, indium vanadate, manganese ferrite and composites, such the relationships are brought out via four main parts including: The first part aims to study efficiency of InVO4/BiVO4 composite films on the photocatalytic activity of methylene blue (MB) degradation. A simple doctor blading coating technique was employed for the fabrication of InVO4, BiVO4 and InVO4/BiVO4 films. The thickness of the as-prepared samples was varied to one, two and three layers. In this research, the photocatalytic experiment demonstrated that the photocatalytic activities of 3-layered InVO4/BiVO4 composite films were enhanced significantly compared to pure InVO4 and BiVO4 films, and the 3-layered 0.2InVO4/0.8BiVO4 composite films showed the highest degradation rate with almost 70% removal of MB concentration of 2 x 10-5 M under visible light irradiation for 120 min. The second part aims to study the effect of pH of synthesizing method on adsorption capability of rhodamine B (RhB) over MnFe2O4. In this study, MnFe2O4 nanoparticles were prepared using a co-precipitation method at five different pH values of 9.0, 9.5, 10.0, 10.5 and 11.0. The adsorption behaviors on Rhodamine B (RhB) by MnFe2O4 nanoparticles prepared at different pH values were investigated. It was found that, via a pH-controlled process, MnFe2O4 nanoparticles prepared at pH 10.5 showed the highest RhB removal efficiency. The results indicated that the large pore size and surface charge of MnFe2O4 nanoparticles improved the adsorption capacities for RhB. The isotherm data showed that the Langmuir maximum adsorption capacity of the MnFe2O4 nanoparticles prepared at pH 10.5 for RhB was 9.30 mg g-1. Kinetic data was fitted to pseudo-second order kinetic model and revealed that equilibrium was reached within 60 min. The third part aims to investigate the efficiency of a new magnetic MnFe2O4/SiO2/BiVO4 composite for degradation of RhB solution in the presence of visible light. The structure, morphology, and properties of these composites, as well as the photocatalytic activity of the composites for the degradation of RhB, were investigated. The efficiency of the photocatalytic process using MnFe2O4/SiO2/BiVO4 composite in RhB solution concentration of 2 x 10-5 M the degradation reached to 73.29%. Furthermore, the kinetics of the rate of this pollutant degradation followed pseudo-second-order kinetics (R2 > 0.99). The findings suggested that after five cycles, the photocatalytic efficiency did not decrease significantly from the first to the last cycle. Based on the results obtained in the present study, the composite catalyst could be effectively separated for reuse by simply applying an external magnetic field. The final part aims to understand the application of magnetic nanocomposites as a catalyst to remove dye pollutants. The MnFe2O4/SiO2/InVO4 composite were successfully fabricated via a hydrothermal method. The magnetization saturation and coercivity values of MnFe2O4/SiO2/InVO4 composite are 18.50 emu g-1 and 86.87 Oe so that the composite microspheres could be effectively separated from the suspension by an external magnetic field. The photocatalytic performance was assessed by RhB (conc. of 2 x 10-5 M) degradation under visible light irradiation. The optimum MnFe2O4/SiO2/InVO4 composite showed a higher (52.74%) photocatalytic activity than other samples. Moreover, the prepared composite showed good stability and recyclability which are beneficial for its practical application.

Chiang Mai University Library

Address: CHIANG MAI

Email: cmulibref@cmu.ac.th

Name: Wiyong Kangwansupamonkon

Role: Chairman

Name: Natda wetchakun

Role: Member

Name: Sumet Sakulsermsuk

Role: Member

Name: Chanokporn Chaiwong

Role: Member

Name: Anucha Watcharapasorn

Role: Member

Created: 2018

Modified: 2020-01-09

Issued: 2020-01-09

วิทยานิพนธ์/Thesis

application/pdf

CallNumber: Th 669.96142 U48D

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degree

Descipline: Materials Science

Grantor: Chiang Mai University

©copyrights Chiang Mai University

ลำดับที่.	ชื่อแฟ้มข้อมูล	ขนาดแฟ้มข้อมูล	จำนวนเข้าถึง	วัน-เวลาเข้าถึงล่าสุด
1	mat80518upld_full.pdf	13.22 MB	15	2026-05-26 18:16:01

ใช้เวลา

0.043626 วินาที