川西平原还田秸秆DOM对矿物细颗粒吸附SMX的影响

为探明还田秸秆溶解性有机质（DOM）对矿物细颗粒吸附磺胺甲恶唑（SMX）的影响机理，研究了矿物细颗粒吸附SMX的动力学过程以及DOM对此过程的影响，比较分析了矿物颗粒吸附前后的傅里叶变换红外光谱（FI-IR）特征.结果表明，SMX在矿物表面的吸附动力学过程符合双室一级动力学模型，表明其吸附过程存在多域吸附或多点位吸附；DOM作用下蒙脱石、钠长石和方解石的吸附量不同程度得到提升，其增量分别为28.94，28.34，2.40μg/g，而3种矿物的模型拟合度均有所降低.通过红外光谱分析，吸附后的蒙脱石较吸附前在波数3700、1600与1000cm^-1附近的尖锐吸收峰和在波数3600~3000cm^-1的宽吸收带明显减弱，而与DOM作用下波谱基本一致，DOM作用下吸附量的提升与蒙脱石溶出Al³⁺与DOM结合使得吸附位点增加有关；钠长石在吸附前后红外光谱一致，而DOM作用下在波数1013、781和460cm^-1处的吸收峰明显减弱，表明DOM被吸附于钠长石表面，通过共吸附或累积方式增加了吸附量；方解石在吸附前后以及DOM作用下红外光谱基本一致，说明DOM对方解石无影响，吸附的增量则源于DOM对SMX的结合.

Effect of DOM derived from straw in West Sichuan plain on fine mineral particle adsorbing SMX

Effect mechanism of the dissolved organic matter (DOM) extracted from crop straw to adsorption processes of sulfamethoxazole (SMX) on the mineral fine particles was tracked. Under the effect of DOM, the adsorption kinetics of SMX on those particles were compared. The fourier transform infrared spectroscopy (FI-IR) characteristics of mineral particles in processes were analyzed. The adsorption kinetics of SMX on the minerals was well fitted by the two-compartment first order kinetic model, implying that the adsorption processes occurred with the adsorption of the multi-domains or multiple sites. Adsorption quantity of SMX with DOM on montmorillonite, albite and calcite, to a certain extent, had the increase of 28.94, 28.34 and 2.40μg/g. However, the fitting degrees of the two-compartment first order kinetic model were decreased. Base on the FI-IR analysis, the peak values of montmorillonite around 3700, 1600 and 1000cm^-1of the wave numbers and the wide range of 3600~3000cm^-1 were weakened. Moreover, the FI-IR characteristics with the DOM effect were similar. The relatively high capacity was related with the supplemental adsorption sites of montmorillonite because of the interaction between Al³⁺ and DOM. The spectral features of the albite in adsorption processes had slight fluctuation. However, the peak values in the DOM-albite-SMX adsorption system decreased significantly around the 1013, 781 and 460cm^-1 of wave numbers. The phenomenon indicated that the adsorbing capacity of albite increased constantly via the common and/or continuous adsorption. Moreover, the spectral characteristics of calcite in the interaction processes of calcite-SMX and DOM-calcite-SMX were analogous, implying little or no effect of DOM. Nevertheless, the increments in the complex matrices could be related to the combination between DOM and SMX.