Natural smectites bind aflatoxins from water effectively, but the complex chemical environment in the guts of mammals and other animals can limit binding of aflatoxins. Many efforts have been made to enhance the adsorption capacity and affinity of smectites for aflatoxins in the presence of biological compounds. The main objective of the present study was to modify smectite structures by pillaring and cation exchange to enhance aflatoxin B1 adsorption capacity and selectivity. Smectite was pillared with Al and Al-Fe polycations or saturated with Ca, Mg, Zn, or Li. Structural changes in smectites with or without heat treatment were determined using X-ray diffraction and Fourier-transform infrared spectroscopy. Equilibrium aflatoxin B1 adsorption to the smectites was measured in aqueous solution and in simulated gastric fluid. Pillaring with the polycations expanded smectites in the z-direction to 18.6 Å and the expansion was stable after heating at 500°C. Changes in the Al–OH–Al infrared bands in the stretching region supported the formation of pillared clays. Migration of Mg, Zn, and Li into the octahedral sites of the smectite was observed as Mg and Zn saturation yielded a d spacing of 15 Å at 200°C which collapsed to 9.6 Å at 400°C. The 14.6 Å peak of the Li-saturated smectite collapsed to 9.6 Å at 200°C while the 15 Å Ca-saturated smectite peak was stable up to 400°C. The unheated Al- and AlFe-pillared smectites adsorbed significantly more aflatoxin B1 from an aqueous suspension than did unpillared clay. In both water and simulated gastric fluid, heat treatment decreased aflatoxin B1 adsorption to pillared smectites, but heat treatment increased aflatoxin B1 adsorption to unpillared smectites. Without heat treatment, smectites saturated with divalent cations (Ca, Mg, Zn) adsorbed more aflatoxin B1 from an aqueous suspension than the smectite saturated with a monovalent cation (Li). Ca-saturated smectite showed the greatest aflatoxin B1 adsorption, 114 g kg^–1, from aqueous suspension after 400°C heat treatment. The Zn-, Mg-, and Li-saturated smectites showed maximum aflatoxin adsorption of 107, 93, and 90 g kg^–1, respectively, after 200°C heat treatment. From simulated gastric fluid with pepsin, the 200°C heated, Zn-saturated smectite had maximum aflatoxin B1 adsorption of 68 g kg^–1. Pillared smectites effectively adsorbed aflatoxin B1 from aqueous suspension, but Ca- and Zn-saturated smectites after heat treatment might improve the selectivity of smectites for aflatoxin B1 over pepsin and enhance the efficacy of smectite as a feed additive.

天然蒙脱石可有效结合水中的黄曲霉毒素，但哺乳动物和其他动物肠道中复杂的化学环境会限制黄曲霉毒素的结合。在生物化合物存在的情况下，已经做出许多努力来提高绿土对黄曲霉毒素的吸附能力和亲和力。本研究的主要目的是通过柱撑和阳离子交换来修饰蒙脱石结构，以提高黄曲霉毒素 B1 的吸附能力和选择性。蒙脱石由铝和铝-铁聚阳离子支撑，或被钙、镁、锌或锂饱和。使用 X 射线衍射和傅里叶变换红外光谱测定经过或未经热处理的蒙脱石的结构变化。在水溶液和模拟胃液中测量了对蒙脱石的平衡黄曲霉毒素 B1 吸附。z方向为 18.6 Å，在 500°C 加热后膨胀稳定。拉伸区域中 Al-OH-Al 红外波段的变化支持柱状粘土的形成。观察到 Mg、Zn 和 Li 迁移到蒙脱石的八面体位置，因为 Mg 和 Zn 饱和产生了d在 200°C 时间距为 15 Å，在 400°C 时收缩至 9.6 Å。Li 饱和蒙脱石的 14.6 Å 峰在 200°C 时坍塌至 9.6 Å，而 15 Å Ca 饱和蒙脱石峰在 400°C 时仍保持稳定。未加热的铝柱和铝铁柱的绿土从水悬浮液中吸附的黄曲霉毒素 B1 比无柱柱的粘土明显多。在水和模拟胃液中，热处理降低了黄曲霉毒素 B1 对柱状蒙脱石的吸附，但热处理增加了黄曲霉毒素 B1 对无柱状蒙脱石的吸附。在没有热处理的情况下，用二价阳离子（Ca、Mg、Zn）饱和的蒙脱石比用单价阳离子（Li）饱和的蒙脱石从水悬浮液中吸附更多的黄曲霉毒素 B1。Ca 饱和的蒙脱石显示出最大的黄曲霉毒素 B1 吸附，114 g kg ^–1, 400°C 热处理后的水悬浮液。锌、镁和锂饱和的蒙脱石在 200°C 热处理后分别显示出 107、93 和 90 g kg ^{–1 的}最大黄曲霉毒素吸附量。从含有胃蛋白酶的模拟胃液中，200°C 加热、锌饱和的蒙脱石具有 68 g kg ^{–1 的}最大黄曲霉毒素 B1 吸附量。柱状蒙脱石可有效吸附水悬浮液中的黄曲霉毒素 B1，但热处理后钙和锌饱和的蒙脱石可能会提高蒙脱石对黄曲霉毒素 B1 的选择性超过胃蛋白酶，并提高蒙脱石作为饲料添加剂的功效。