Wastewater treatment with PTFE membrane bio-reactor | Author : Mai FURUKAWA, Ikki TATEISHI, Satoshi KANECO, Hideyuki KATSUMATA, Tohru SUZUKI, Yutaka HOMON, Ahmed H.A. DABWAN | Abstract | Full Text | Abstract :Recently, the introduction of separation membranes is progressing in the field of sewage and industrial wastewater treatment. The treatment methods with membrane separation have many advantages. Firstly, the sedimentation tank has not been required for the sake of gravity sedimentation. It is possible that the reaction tank become compact. Secondly, suspended solids (SS) can be almost completely removed, and it is possible to produce clarified treated water for which even bacteria and viruses can be almost completely removed. For this research, a new and novel separation polytetrafluoroethylene (PTFE) membrane has been produced, and the membrane has been applied to membrane bioreactor and membrane separation coagulation sedimentation treatments on an actual sludge treatment center. The experiment data was obtained through continuous operation during over approximately one year, and did show the similar good performance to a chlorinated polyethylene (CPE) membrane. As a result, the fouling resistance was considerably improved when using the flat PTFE membrane compared to the flat CPE membrane. |
| Effects of operational parameters on degradation of methyl orange dye over nanosized CdS photocatalyst under UV Radiation | Author : Fikadu Tsehaye, Om Prakash Yadav and Lokesh Yadav | Abstract | Full Text | Abstract :Nano-sized CdS has been prepared by aqueous chemical method using glycine as a capping and stabilizing agent. X-ray diffraction (XRD) analysis of as-synthesized material revealed hexagonal wurtzite structure of CdS with average crystallite size 48.1 nm. The observed FTIR spectra support the template role of glycine in controlling the size of CdS nanoparticles. Photo-catalytic efficiency of CdS nanoparticles was investigated under UV irradiation following degradation of methyl orange (MO), as a probe. Effect of some operational parameters such as photo-catalyst load, pH of solution and substrate (MO) initial concentration on the photo-catalytic degradation of the dye have been investigated. Using methyl orange initial concentration 300 mg/L, optimum photo-catalyst load 120 mg /L and pH 4.0, as high as 92 % degradation of methyl orange could be achieved under UV radiation. The photo-catalytic method developed here can be used for large scale treatment of water bodies contaminated with methyl orange dye. |
| Gamma ray attenuation technique to the measurement of moisture content profiles in porous building materials | Author : Ana Sofia GUIMARÃES and Isabel Martins RIBEIRO | Abstract | Full Text | Abstract :The knowledge of moisture transport in porous building materials and components is crucial to predict and avoid several pathologies and is essential to increase the durability. It is easy to know the amount of water that, for example, some material absorbs when in contact with water. However, it is very difficult to determine where the water is, the water transport process, the water movement, etc. Using the gamma ray attenuation technique, it is possible to determine the water content along a building material or component and obtained the water content profile in different moments. So, with this tool, several phenomena can be studied such as: the wetting and drying processes, the thermal performance, waterproof behavior, etc,. This paper presents the gamma ray attenuation technique, the way that the water content profiles can be obtained, some interesting water content profiles obtained for a material, monolithic and multilayered and the discussion of those results. |
| Evaluation of Carbon Nanotube Buckypaper as a Sorbent for Passive Sampling of Toluene | Author : Samantha L CONNELL, Evan L FLOYD and Claudiu T LUNGU | Abstract | Full Text | Abstract :Passive air sampling is a preferred method of air sampling for many applications. Traditionally, this method uses activated carbon as the sorbent and samples are analyzed by chemical or thermal desorption. This research explores the use of carbon nanotubes in the form of a buckypaper as a sorbent for passive sampling by comparing the mass uptake and percent yield to that of the 3M™ Organic Vapor Monitor 3500 over four time trials (30, 60, 120 and 240min) using toluene as the sorbate. A total of 48 samples were taken and results were analyzed using a gas chromatograph. The desorption efficiency and mass uptake rate of the carbon nanotube sorbents were similar to the 3M™ Organic Vapor Monitor 3500. Desorption efficiencies were 85.5 – 100.3% for 3M samplers and 89.5 – 95.5% for carbon nanotube sorbents. The mass of toluene collected at 30-minute and 120-minute time trials showed no significant differences (p = 0.37, 0.1, respectively) while 60min and 240min time trials were significantly different with fabricated sorbents collecting closer to the expected mass (p = 0.02, 0.04 respectively). Overall sampling capacity is lower in the 20mg carbon nanotube buckypapers compared to the 200mg activated carbon pad of the 3M™ OVM 3500 due to somewhat lower adsorption capacity and much lower sorbent mass. While the objective of this study was to explore the suitability of buckypaper sorbents for sampling exposures at low concentration for short durations, a larger mass buckypaper sorbent should provide a similar sampling capacity to standard passive samplers. |
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