Korean Chemical Engineering Research, Vol.43, No.1, 60-65, February, 2005
표면처리 활성탄소섬유에 의한 U(VI)의 전기흡착
Electrosorption of U(VI) by Surface-Modified Activated Carbon Fiber
E-mail:
초록
연속적 전기흡착 셀에서 활성탄소섬유 부직포 전극을 사용하여 U(VI) 함유 폐액을 처리하였다. 더 낮은 전위에서 U(VI)의 전기흡착 효율을 높이기 위하여 ACFs를 화학약품으로 표면처리하고 그의 세공구조 및 관능기의 변화를 조사하였으며 처리조건이 U(VI)의 흡착에 미치는 영향을 고찰하였다. 표면처리한 모든 ACFs의 비표면적은 감소하였다. 중성염 및 염기성 용액으로 처리한 ACFs의 산성관능기는 감소했지만 산성 용액으로 처리한 ACFs의 산성관능기는 증가하였다. 산성관능기는 U(VI)의 흡착을 차단하여 산성용액 처리 ACFs 전극은 흡착용량이 크게 증가하여 -0.3 V의 낮은 전위에서도 처리하지 않은 ACFs 전극의 -0.9 V에 상응하는 결과를 얻었다. 이러한 결과는 ACFs 표면의 산성관능기 감소에 의한 이온의 차단효과(Shielding effect)가 줄어들 뿐만 아니라 음전위 가용에 의한 전기이중층 내에서의 OH-의 증가로 U(VI) 흡착이 효율적으로 진행되었기 때문이다.
The electrosorption of U(VI) from waste water was carried out by using activated carbon fiber(ACF) felt electrode in a continuous electrosorption cell. In order to enhance the electrosorption capacity at lower potential, ACF felt was chemically modified in acidic, basic and neutral solution. Pore structure and functional groups of chemically modified ACF were examined, and the effect of treatment conditions was studied for the adsorption of U(VI). Specific surface area of all ACFs decreases by this treatment. The amount of acidic functional groups decreases with basic and neutral salt treatment, while the amount increases a lot with acidic treatment. The electrosorption capacity of U(VI) decreases on using the acid treated electrode due to the shielding effect of acidic functional groups. Base treated electrode enhances the capacity due to the reduction of acidic functional groups. The electrosorption amount of U(VI) on the base treated electrode at .0.3 V corresponds to that of ACF electrode at .0.9 V. Such a good adsorption capacity was not only due to the reduction of shielding effect but also the increase of OH . in the electric double layer on ACF surface by the application of negative potential.
Keywords:Electrosorption;Activated Carbon Fiber;Uranium Ion(VI);Surface Modification;Electric Double Layer
- Carley-Macauy KW, Gutman RG, Radioactive Waste: Advanced management methods for medium Active Liquid Waste, Harwood Academic Pub (1981)
- Woodard FE, McMackins DE, Jansson REW, J. Electroanal. Chem., 214, 303 (1986)
- Oren Y, Soffer A, J. Appl. Electrochem., 13, 473 (1983)
- Jayson GG, Sangster JA, Thompson G, Wilkinson MC, Carbon, 25, 523 (1987)
- Oren Y, Soffer A, Electrochim. Acta, 28, 1649 (1983)
- Ryu SK, High Temp.-High Press., 22, 345 (1990)
- Marsh H, Heintz EA, Rodriguez-Reinoso F, "Introduction to Carbon Technologies", University of Alicante, 42-45 (1997)
- Park SJ, Park BJ, Ryu SK, Carbon, 37, 1223 (1999)
- Hong LI, Moshonov A, Muzzy JD, Polym. Compos., 12, 191 (1991)
- Drzal LT, Madhukar M, J. Mater. Sci., 28, 569 (1993)
- Brunauer S, Emmett PH, Tellet E, J. Am. Chem. Soc., 60, 309 (1938)
- Boehm HP, Carbon, 7, 715 (1969)
- Park SJ, Interfacial forces and field: theory and application, 1st ed, J. P. Hsu, Marcel Dekker, New York (1999)
- Shim JW, Park SJ, Ryu SK, Carbon, 39, 1635 (2001)
- Pittman CU, He GR, Wu B, Garner SD, Carbon, 35, 317 (1997)
- Kim HS, Ryu SK, Jung CH, Park KK, HWAHAK KONGHAK, 41(6), 744 (2003)
- Jung CH, "A Study on the Preparation of Activated Carbon Fibers and Their Radioactive Co(II) Adsorption Characteristics", Ph.D. Dissertation, ChungnamNational Univ., Deajeon, Korea (1994)
- Park SJ, Kim YM, Shin JS, J. Korean Ind. Eng. Chem., 14(1), 41 (2003)
- Takamura T, Awano H, Ura T, Ikezawa Y, "Effective Surface Treatment to IMprove the Li Doping and Undoping Characteristics of Carbon Fiber as a Li Secondary Battery Anode", 36th Battery Symposium, Japan, 92-92 (1995)