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Li P.,Advanced Material Technology Center
International Biodeterioration and Biodegradation | Year: 2013

Sewage sludge, with zero recycling rate, poses landfill problems as Semakau island, the dumping site, is rapidly occupied in within a short period of time. Dried sewage sludge was heated at different temperatures ranging from 200°C to 700°C over various heating times of 2-5h. The heated dried sludge (DS) was equilibrated with methylene blue (MB) solutions at different concentration to determine the optimum adsorption time, effect of different heating temperatures of sludge, effect of pH and effect of adsorbent concentration on the percentage of MB adsorbed. The results were compared to a commercial activated carbon (AC) in adsorbing the same MB concentration. The higher heating temperatures the more the DS was able to adsorb MB. DS, which was heated at 700°C, showed the highest percentage of MB adsorbed of 95%, compared to that of AC, which were 91.20% (Grade 17) and 97.99% (Grade 19), whenadsorbing the same initial MB concentration of 10μmoll-1. However, DS heated at 200°C for 5h (DS-200-5) was found to have a ratio of MB adsorbed per power consumption of 21.568 (μmoll-1kW), the highest ratio among the other sludge samples, making it the most cost effective type of sludge. Overall, DS was able to adsorb MB between 90% and 98% at a wide pH range of 3 Source


Tao Y.,Advanced Material Technology Center | Yin X.J.,Advanced Material Technology Center
Nanotechnology 2010: Bio Sensors, Instruments, Medical, Environment and Energy - Technical Proceedings of the 2010 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2010 | Year: 2010

Photocatalytic degradation of phenol was examined in slurry reactor with UV light irradiation using ZnO nanopowder as a photocatalyst. The effects of process parameters such as catalyst dosage, initial concentration of phenol, initial pH value of aqueous solutions and different anions on the degradation efficiencies of phenol were systematically investigated with high performance liquid chromatography (HPLC). The kinetic rate constants were evaluated by the changes in the phenol concentration and catalyst dosage. The degradation kinetics of phenol followed the pseudo first-order kinetics. Source


Tao Y.,Advanced Material Technology Center | Yin X.-J.,Advanced Material Technology Center
Sustainable Environment Research | Year: 2010

The removal of bacteria such as Escherichia coli from water using U VA radiation from fluorescent lamp, cold cathode lamp and light emitting diodes (LED) coupled with different kinds of nano-semiconductors such as ZnO and TiO2 as photocatalysts was studied. The effectiveness in removal of E. coli by UVA and UVC was also compared. The results showed that UVA cold cathode lamp had the highest removal efficiency. The contact time for an 80% removal for U VA cold cathode lamp was only 10 min whilst for the normal U VA fluorescent lamp and LEDs the contact time was 15 and 45 min, respectively. The effectiveness of different concentrations of nano-semiconductors as photocatalysts (0.01-1.0 g L-1) in the removal of E. coli was studied. The results showed that U VA cold cathode lamp coupled with 0.01 g L-1 TiO2 photocatalyst could be recommended in the removal of pathogens from water. The comparative studies on the effectiveness of different kinds of nano-semiconductors in the removal of pathogens from water were also carried out, and it was found that nanoscale ZnO is more effective than nanoscale TiO2. © 2010, Chinese Institute of Environmental Engineering. All rights reserved. Source


Tao Y.,Advanced Material Technology Center | Shan D.,Advanced Material Technology Center | Yin X.J.,Advanced Material Technology Center
International Journal of Photoenergy | Year: 2012

This study investigated the applicability of maghemite (-Fe2O3) nanoparticles for the selective removal of toxic heavy metals from electroplating wastewater. The maghemite nanoparticles of 60nm were synthesized using a coprecipitation method and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDX). Batch experiments were carried out for the removal of Pb2+ ions from aqueous solutions by maghemite nanoparticles. The effects of contact time, initial concentration of Pb 2+ ions, solution pH, and salinity on the amount of Pb2+ removed were investigated. The adsorption process was found to be highly pH dependent, which made the nanoparticles selectively adsorb this metal from wastewater. The adsorption of Pb 2+ reached equilibrium rapidly within 15min and the adsorption data were well fitted with the Langmuir isotherm. © Copyright 2012 Zuolian Cheng et al. Source

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