Preparation of titanium dioxide nanoparticles from electrocoagulated sludge using sacrificial titanium electrodes.
ABSTRACT A comprehensive investigation of electrocoagulation using sacrificial titanium (Ti) electrodes in wastewater was carried out. The effects of specific process variables, such as initial pH, mixing, current density, initial organic loading, and ionic/electrolyte strength were first optimized to produce recyclable Ti-based sludge. The sludge was incinerated at 600 degrees C to produce functional TiO(2) photocatalyst. X-ray diffraction analysis revealed that TiO(2) produced at optimum electrocoagulation conditions was mostly anatase structure. The specific surface area of the synthesized TiO(2) photocatalyst was higher than that of the commercially available and widely used Degussa P-25 TiO(2). Furthermore, energy dispersive X-ray and X-ray photoelectron spectroscopy analyses showed that in additional to titanium and oxygen, this photocatalyst is also composed of carbon and phosphorus. These elements were mainly doped as a substitute site for the oxygen atom. Transmission electron microscopy images exhibited sharply edged nanorods, round nanoparticles, and nanotubes with nonuniform shapes showing some structural defects. Photodecomposition of gaseous acetaldehyde by this photocatalyst was also conducted under UV and visible light irradiation to study the photocatalytic properties of the doped TiO(2) photocatalyst. While no photocatalytic activity was observed under visible light irradiation, this doped TiO(2) photocatalyst exhibited high photocatalytic activity under UV light.
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ABSTRACT: The objective of this study is to investigate the feasibility of solar powered electrocoagulation (SPEC) for wastewater treatment using aluminium electrodes. Optimisation of various operating parameters such as pH, voltage/current, electrodes gap, pollutant concentration etc. were first performed using direct electrical current. SPEC reactor was designed by connecting with photovoltaic panel (PV) either directly or through a set of batteries and charge control system. SPEC process system was sensitive to variation of solar radiation when connected directly with PV panels. SPEC reactor operated for five different times in a day (4 April 2010) yielded highest organics removal of 85% for UV abs and turbidity removal of 87% at midday (10:00 AM–2:00 PM) under optimum operating conditions. Use of batteries and charge controller with PV panels provided more consistent and efficient performance for the SPEC reactor. The variation in organics and turbidity removal was within the range of 10% for experiments conducted on three different times in a day (9 April 2010) with highest removals at 10:30 AM in the morning. This study indicates that, SPEC is a potential alternative for small scale decentralised water and wastewater purification system.Desalination and water treatment 01/2011; 32:381-388. · 0.85 Impact Factor
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ABSTRACT: The fouling study of crossflow microfiltration (MF) was comparatively studied with feedwater containing kaolin suspension with and without electrocoagulation (EC) pre-treatment. An acrylonitrile butadiene styrene (ABS) MF membrane of pore size 0.4 μm was used in this study. The experiments were carried out at three different concentration of kaolin (100, 400 and 800 mg/l) and with three different crossflow velocities of 0.5, 1 and 1.5 l/min. When the feedwater was pre-treated by EC, the fouling was found to follow standard law of filtration. Besides the standard filtration law, the fouling mechanism also followed the classical cake filtration model due to formation of a secondary membrane.Desalination and Water Treatment - DESALIN WATER TREAT. 01/2012; 43:253-259.