Peak D, Ford RG, Sparks DL
Department of Plant and Soil Sciences, University of Delaware, 149 Townsend Hall, Newark, Delaware, 19717-1303
J Colloid Interface Sci. 1999 Oct 1;218(1):289-299. doi: 10.1006/jcis.1999.6405.
The mechanism of sulfate adsorption on goethite was investigated in situ using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Sulfate adsorption was investigated at ionic strengths between 0.005 and 0.1 M, reactant concentrations between 5 and 500 µM, and pH values between 3.5 and 9.0. It was determined that sulfate forms both outer-sphere and inner-sphere surface complexes on goethite at pH less than 6. At pH values greater than 6, sulfate adsorbs on goethite only as an outer-sphere complex. The relative amount of outer-sphere sulfate surface complexation increased with decreasing ionic strength. The spectrum of sulfate adsorbed on goethite was also compared to the infrared spectrum of synthetic schwertmannite, an iron(III) oxy-hydroxy-sulfate. It was determined that in situ spectra of both schwertmannite and adsorbed sulfate are quite similar, suggesting that a continuum of outer- and inner-sphere sulfate occurs in both cases. Copyright 1999 Academic Press.
利用衰减全反射傅里叶变换红外光谱（ATR-FTIR）原位研究了针铁矿对硫酸盐的吸附机制。在离子强度为0.005至0.1 M、反应物浓度为5至500 μM以及pH值为3.5至9.0的条件下研究了硫酸盐吸附情况。结果表明，在pH小于6时，硫酸盐在针铁矿上形成外层和内层表面络合物。在pH值大于6时，硫酸盐仅以外层络合物形式吸附在针铁矿上。外层硫酸盐表面络合的相对量随离子强度降低而增加。还将吸附在针铁矿上的硫酸盐光谱与合成施韦特曼石（一种铁（III）羟基硫酸盐）的红外光谱进行了比较。结果表明，施韦特曼石和吸附硫酸盐的原位光谱非常相似，表明在这两种情况下都存在外层和内层硫酸盐的连续体。版权所有1999年学术出版社。
