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Recovery of Pentachlorophenol from Aqueous Solution via Silicone Rubber Membrane

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Advances in Chemical Engineering and Science 2012年第3期2卷 372-378页

作者： Jun Sawai Ko-Ichi Sahara Tamotsu Minami mikio kikuchi Faculty of Applied Bioscience Kanagawa Institute of Technology Atsugi Japan

Although pentachlorophenol (PCP) has been widely employed as a biocide for over 60 years, its production and use are currently severely curtailed in many countries due to its extreme toxicity. In recent years, the contamination of both soil and surface waters by PCP has become a concern. In this study the permeation characteristics of PCP penetrating silicone rubber membranes (SRM) were studied, in order to determine the feasibility of separation of PCP from water via the permeation and chemical desorption (PCD) method. It was found that efficient separation and recovery of PCP could be obtained using an acidic feed solution and an alkaline recovery solution. The permeation rate of PCP into the SRM was optimized when the feed solution was maintained at a pH of 4 or lower. The SRM thickness did not significantly affect the permeation rate, indicating that the rate determining step for the process is the initial movement of the PCP into the SRM. The activation energy for the penetration process was determined to be quite high, and thus thermal controls will play an important role in the recovery of PCP by this method. The membrane distribution coefficient (mc) for PCP moving into SRM was large and showed a strong correlation to permeation rates reported previously, confirming that PCD is a suitable technique for the separation and recovery of PCP from aqueous solution.

关键词： Persistent Organic Pollutants (POPs) Soil Pollution Membrane Separation Polymer Membrane Partition Coefficient

Disinfection Treatment of Heated Scallop-Shell Powder on Biofilm of <i>Escherichia coli</i>ATCC 25922 Surrogated for <i>E. coli</i>O157:H7

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Journal of Biomaterials and Nanobiotechnology 2013年第4期4卷 10-19页

作者： Miki Kubo Yori Ohshima Fumio Irie mikio kikuchi Jun Sawai Faculty of Applied Bioscience Kanagawa Institute of Kanagawa Atsugi Japan

The ability of heated scallop-shell powder (HSSP) to disinfect Escherichia coli ATCC 25922 biofilm was investigated. On account of its cryotolerance and cell surface characteristics, the E. coli strain is reportedly a useful surrogate for E. coli O157: H7 in surface attachment studies. In this study, an E. coli ATCC 25922 biofilm was formed on a glass plate, and immersed in a slurry of HSSP. Following treatment, the disinfection ability of the HSSP toward the biofilm was non-destructively and quantitatively measured by conductimetric assay. The disinfection efficacy increased with HSSP concentration and treatment time. HSSP treatment (10 mg/mL, pH 12.5) for 20 min completely eliminated biofilm bioactivity (approximately 108 CFU/cm2 in non-treated biofilms). In contrast, treatment with NaOH solution at the same pH, and treatment with sodium hypochlorite (200 mg/mL) reduced the activity by approximately one to three log10. Fluorescence microscopy confirmed that no viable cells remained on the plate following HSSP treatment (10 mg/mL). Although alkaline and sodium hypochlorite treatments removed cells from the biofilm, under these treatments, many viable cells remained on the plate. To elucidate the mechanism of HSSP activity against E. coli ATCC 25922, the active oxygen generated from the HSSP slurry was examined by chemiluminescence analysis. The luminescence intensity increased with increasing concentration of HSSP slurry. The results suggested that, besides being alkaline, HSSP generates active oxygen species with sporicidal activity. Thus, HSSP treatment could also be effective for controlling biofilms of the toxic strain E. coli O157: H7, implicated in food poisoning.

关键词： Scallop-Shell Powder Biofilm Escherichia coli Conductimetric Assay Fluorescence Microscopy Active Oxygen Alkali

Separation and Recovery of Iodine from Aqueous Solution by Permeation and Chemical Desorption (PCD) Using a Silicone Rubber Membrane

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Advances in Chemical Engineering and Science 2012年第4期2卷 508-513页

作者： Jun Sawai Hitomi Tomizuka Naoki Hatanaka Tamotsu Minami mikio kikuchi Toshimitsu Ishii Faculty of Applied Bioscience Kanagawa Institute of Technology Atsugi Kanagawa Japan Godo Shigen Sangyo Co. Ltd. Nanaido Chosei-mura Chosei-gun Chiba Japan

New technologies for iodine separation and recovery are required to decrease environmental pollution and improve iodine production. Separation and recovery of iodine (I2) in aqueous solution was achieved using permeation and chemical desorption (PCD) with a silicone rubber membrane (SRM). The SRM separated an aqueous feed solution from an alkaline or reducing recovery solution such as a mixture of sodium hydrate and sodium sulfate. The I2 crossed the membrane from the aqueous feed solution into the recovery solution, where it was converted into iodide (I–). Iodide in the recovery solution did not return to the feed solution across the SRM. An acidic feed solution promoted a high recovery of iodine. The permeation process followed first-order kinetics, allowing the overall mass-transfer coefficient and parameters related to permeation of I2 through the SRM to be determined. Permeability of I2 increased with temperature, and the apparent activation energy (Ea) for penetration of I2 through the SRM was determined. The value of Ea for I2 was of the same order of magnitude as those for phenols and anilines. The large membrane/aqueous distribution coefficient for I2 indicated that I2 had a high affinity toward the SRM. These results indicate that the PCD method is effective and powerful for separation and recovery of iodine from aqueous solutions.

关键词： Membrane Separation Permeation and Chemical Desorption (PCD) Method Diffusion Coefficient Membrane/Aqueous Distribution Coefficient Polydimethylsiloxane

Perianal tuberculosis: A case report and review of the literature

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World Journal of Clinical Cases 2015年第9期3卷 848-852页

作者： Sayaka Tago Yuji Hirai Yusuke Ainoda Takahiro Fujita mikio Takamori Ken kikuchi Department of Infectious Diseases Tokyo Women’s Medical University Department of Pulmonary Medicine Tokyo Metropolitan Tama Medical Center

Tuberculosis(TB) is still a major health problem worldwide. We present a rare case of an immunocompetent patient with perianal TB. A 38-year-old man visited a clinic with pain, swelling, and redness in the perineum. He had been persistently coughing for the past 6 mo. The abscess had formed a fistula to the perianal region, indicating perianal abscess. Mycobacterium tuberculosis was found in sputum and perianal abscess. Surgical drainage was performed, and oral anti-tuberculous drugs were administered for 6 mo. The patient's clinical course was favorable. On review of the literature on 58 cases of perianal TB, we found that the duration of persistent perianal lesion was much longer in patients without active pulmonary TB(APTB) than in those with APTB(66.4 mo vs 8.3 mo; confidence interval, 0.0760-0.9620, P = 0.0380). Thus, in cases of non-healing or recurrent perianal lesions, TB should be considered.

关键词： Tuberculosis Abscess Ulcer Hemorrhoids Fistula