Synthesis of Ag-doped TiO2 nanoparticles via sol-gel method for antibacterial air filter

การสังเคราะห์อนุภาคนาโนไทเทเนียมไดออกไซด์ที่มีการเจือโลหะเงินด้วยวิธีการโซลเจลเพื่อประยุกต์ใช้สำหรับแผ่นกรองอากาศยับยั้งแบคทีเรีย

Name: Siripond Phromma

keyword: Antibacterial air filter

; Ag doped titanium dioxide

; Dry and wet ball milling sol-gel method

; Photocatalytic activity

; Self-cleaning

; Antibacterial activity

Abstract: Titanium dioxide (TiO2) is well-known for its high antibacterial activity. The application of TiO2 for antibacterial air filter has been recognized but the limitation of photocatalytic reaction on dependency of UV light has still been a challenge. TiO2 modified with silver (Ag-TiO2) has attracted much attention and applied in a wide range of applications especially as an antibacterial agent in recent years. However, its low photocatalytic activity, antibacterial activity, and surface area limit the potential use and capabilities in antibacterial air filter. In this study, Ag-TiO2 were synthesized via dry and wet ball milling sol-gel method (DWBMS) and dip coated on commercial air filter to produce antibacterial air filter, which can be used under UV light and dark condition. First, synthesis of TiO2 nanoparticles (NPs) via DWBMS was conducted. The influences of various alcohol types used and varied calcination temperature were investigated. The results suggested the optimal synthesis conditions to be applied for the synthesis of Ag-TiO2 NPs in the next step. Methanol as a solvent was found to be the most suitable reagent for TiO2 synthesis with smallest particle size and narrow size distribution of 8.1±2.1 nm and highest photocatalytic efficiency of 8.5x10-4 min-1 compared to ethanol and isopropanol. Calcination temperature in the range of 300-800°C was observed. It was found that the calcination temperature plays an essential role for phase transition, crystallite size, particle size, and crystallinity of TiO2. The high amount of anatase phase mixed with brookite and rutile phases had a strong effect on the photocatalytic activity between 300 and 600°C while the crystallite and particle size of TiO2 had a dominant influence on the photocatalytic activity from 600 to 700°C. The highest photocatalytic activity with the kinetic constant rate of 1.70x10-3 min-1 was achieved with TiO2 calcined at 600 °C. Next, Ag-TiO2 NPs were synthesized via DWBMS with methanol as solvent, and calcination temperature of 600°C. Photocatalytic and antibacterial activities of Ag-TiO2 were determined by the effect concentration of Ag from 3% to 10% by mole of Ag. It was found that the optimal amount at 5%Ag-TiO2 showed the highest photocatalytic activity with the kinetic constant rate of 2.02x10-3 min-1. At last, the effect of dipping speed, binder concentration, and coating solution concentration were investigated to propose the optimal coating conditions. Then, the solution of synthesized 5% Ag-TiO2 was dip-coated on F9 air filter. The selected conditions were ; 0.50 mm/s dipping speed, 1%v/v PPG-4000 as binder, and 10%w/v of 5% Ag-TiO2. It was clearly seen that the coated air filter offered the bacterial reduction efficiency up to 99.99%, under both UV-light and dark conditions

Thammasat University. Thammasat University Library

Address: BANGKOK

Email: preserv@tu.ac.th

Name: Tippapust Eksangsri

Role: advisor

Name: Chaweewan Sapcharoenkun

Role: co-advisor

Created: 2017

Modified: 2022-02-01

Issued: 2022-02-01

วิทยานิพนธ์/Thesis

application/pdf

DOI: 10.14457/TU.the.2017.1748

eng

DegreeName: Master of Engineering

Level: Master's Degree

Descipline: Energy and Environmental Technology Management

Grantor: Thammasat University

©copyrights Thammasat University

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