pH 4와 10에서의 3가 비소와 Two-Line Ferrihydrite의 표면반응에 대한 X선 흡수 분광 연구 = X-ray Absorption Spectroscopy Study on Surface Interaction of Arsenite onto Two-Line Ferrihydrite at pHs 4 and 10

국문 초록 (Abstract)

본 연구에서는 자연에서 산출빈도가 높은 3가 비소(아비산염)와 two-line ferrihydrite와의 표면흡착 반응의 기작을 살펴보기 위하여 3가 비소를 흡착시킨 two-line ferrihydrite에 대한 X선 흡수분광 분석을 수행하였다. 연구에 사용된 two-line ferrihydrite는 실험실에서 합성하여 사용하였으며, 산성과 염기성 환경에서의 표면반응 기작을 비교하기 위하여 pH 4와 10에서 연구를 수행하였다. 또한 각 pH 조건별 3가 비소의 흡착농도에 따른 표면반응의 차이를 비교 평가하였다. X선 흡수분광 분석결과에서 얻은 EXAFS영역에서의 비소 3가에 대한 구조 변수들을 살펴보면 As-O 배위수는 3.1~3.3개, 거리는 1.74~1.79 Å으로 two-line ferrihydrite 표면에 흡착된 As(III) complex의 구조 단위체가 AsO3임이 확인되었다. As(Ⅲ)-Fe쌍은 주로 안정된 형태의 bidentate binuclear corner-sharing (2C)의 결합구조를 갖는 것으로 나타났으며, bidentate mononuclear edge-sharin g(2E)와 2C가 혼합된 결합구조도 공존하는 것으로 조사되었다. pH 4에서는 흡착 농도에 따라 다른 표면구조를 가지는 반면, pH 10에서는 흡착 농도에 상관없이 동일한 표면구조를 보이는 것으로 나타났다. 이러한 결과는 3가 비소와 two-line ferrihydrite의 표면반응은 pH와 농도에 의해서 영향을 받는다는 거시적인(macroscopic) 흡착실험 연구결과가 미시적인(microscopic) X선 흡수분광 결과에 의해서 해석될 수 있음을 의미한다.

다국어 초록 (Multilingual Abstract)

X-ray absorption spectroscopy (XAS) study was conducted using arsenite-sorbed two-line ferrihydrite to investigate the mechanism of surface interactions between two-line ferrihydrite and As(III) (arsenite) which are ubiquitous in nature. The two-line ferrihydrite used was synthesized in the laboratory and the study was undertaken at pHs 4 and 10 to compare the difference in mechanisms of surface interaction between acidic and alkaline environments. The effect of arsenite-adsorbed concentrations on surface complexation was investigated at each pH condition as well. From the results of XAS analyses, the structural parameters of arsenite in the EXAFS revealed that the coordination number and distanceof As-O were 3.1~3.3 and 1.74~1.79 Å, respectively, which indicate that the unit structure of arsenite complex formed on the surface of two-line ferrihydrite is AsO3. The dominant structures of As(III)-Fe complex were examined to be bidentate binuclear corner-sharing (2C) and the mixture of bidentate mononuclear edge sharing (2E) and 2C appeared as well. At pH 4, arsenite complex showed different structures on the surface of two-line ferrihydrite, depending on the adsorbed concentrations. At pH 10, on the contrary, the surface structures of arsenite complexes were interpreted to be almost identical, irrespective of the adsorbed concentrations of arsenite. Consequently, this microscopic XAS results support the results of macroscopic adsorption experiments in which the surface interaction between arsenite and two-line ferrihydrite is significantly influenced by pH conditions as well as arsenite concentrations.

참고문헌 (Reference)

1 고경석, "황산염처리 산화철피복모래의 비소 흡착능 평가 연구" 445-448, 2006

2 김순오, "침철석(goethite)과 비소의 흡착반응" 한국광물학회 22 (22): 177-189, 2009

3 정현수, "자철석의 비소에 대한 흡착특성 연구" 한국광물학회 21 (21): 423-432, 2008

4 김순오, "영가철을 이용한 광미 용출액으로부터 비소 제거에 관한 연구" 149-149, 2006

5 고일원, "비소의 적철석 표면 흡착에 토양유기물이 미치는 영향: 화학종 모델링과 흡착 기작" 대한자원환경지질학회 38 (38): 23-31, 2005

6 정영일, "비소의 Two-Line Ferrihydrite에 대한 흡착반응" 한국광물학회 21 (21): 227-237, 2008

7 정영일, "비소의 Two-Line Ferrihydrite에 대한 흡착반응" 한국광물학회 21 (21): 227-237, 2008

8 김순오, "비소와 영가철 및 철(수)산화물과의 표면반응에 대한 X선 흡수분광 예비연구" 안동대학교 131-134, 2007

9 이우춘, "레피도크로사이트(lepidocrocite) 표면의 비소 흡착 특성 규명" 대한자원환경지질학회 42 (42): 95-105, 2009

10 고일원, "나노 크기 적철석 입자 피복 모래를 이용한 비소 3가 와 비소 5가의 제거" 한국지하수토양환경학회 9 (9): 63-69, 2004

11 Manceau, A, "The mechanism of anion adsorption on iron oxides: Evidence for the bonding of arsenate tetrahedral on free Fe(O, OH)6 edges" 59 : 3647-3653, 1995

12 Sherman, D.M, "Surface complexaton of arsenic(V) to iron(III) (hydr)oxides: Structural mechanism from ab initio molecular geometries and EXAFS spectroscopy" 67 : 4223-4230, 2003

13 Waychunas, G.A., "Surface chemistry of ferrihydrite: Part I. EXAFS studies of the geometry of coprecipitated and adsorbed arsenate" 57 : 2251-2269, 1993

14 Fuller, C.C., "Surface chemistry of ferrihydrite: Part 2. Kinetics of arsenate adsorption and coprecipitation" 57 : 2271-2282, 1993

15 Soon-Oh Kim, "Removal of Arsenic from Leachate of Tailing using Laboratory-synthesized Zerovalent Iron" 한국응용생명화학회 50 (50): 6-12, 2007

16 Ankudinov, A.L, "Real space multiple scattering calculation and interpretation of X-ray absorption near edge structure" 58 : 7565-7576, 1998

17 Farquhar, M.L, "Mechanisms of arsenic uptake from aqueous solution by interaction with goethite, lepidocrocite, mackinawitee, and pyrite: An X-ray absorption spectroscopy" 36 : 1757-1762, 2002

18 김순오, "Long-term evaluation of the feasibility of zerovalent iron for the removal of arsenic and heavy metals from tailing-leachate" 지질과학기술 공동학회 382-384, 2007

19 Schwertmann U, "Iron oxides in the laboratory: preparation and characterization" Wiley-VCH Publishers 103-112, 2000

20 Morin, G, "Extended x-ray absorption fine structure analysis of arsenite and arsenate adsorption on maghemite" 42 : 2361-2366, 2008

21 Ona-Nguema, G, "EXAFS analysis of arsenite adsorption onto two-line ferrihydrite, hematite, goethite, and lepidocrocite" 39 : 9147-9155, 2005

22 Dixit, S, "Comparison of arsenic (V) and arsenic(III) sorption onto iron oxide minerals: implications for arsenic mobility" 37 : 4182-4189, 2003

23 Raven, K.P., "Arsenite and arsenate adsorption on ferrihydrite: Kinetics, equilibrium, and adsorption envelopes" 32 : 344-349, 1998

24 Manning, B.A, "Arsenic(III) and arsenic(V) reactions with zerovalent iron corrosion products" 36 : 5455-5461, 2002

25 Masue, Y, "Arsenate and arsenite adsorption and desorption behavior on coprecipitated aluminum:iron hydroxides" 41 : 837-842, 2007

26 Jung, Y.I, "Application of zerovalent iron for the removal of arsenic from leachate of tailing" 52-, 2007

27 Wilkie, J.A, "Adsorption of arsenic onto hydrous ferric oxide: effects of adsorbate/adsorbent ratios and co-occurring solutes" 107 : 97-110, 1996

28 Ravel, B, "ATHENA, ARTEMIS, HEPHAESTUS: data analysis for X-ray absorp tion spectroscopy using IFEFFIT" 12 : 537-541, 2005