Wang Qun, Zhang John P, Smith Timothy R, Hurst William E, Sulpizio Thomas
World Minerals Inc., 2500 Miguelito Road, Lompoc, CA 93436, USA.
Colloids Surf B Biointerfaces. 2005 Aug;44(2-3):110-6. doi: 10.1016/j.colsurfb.2005.06.005.
A synthetic, disposable adsorbent of crystalline calcium silicate hydrate, LRA product by Advanced Minerals Corp., has been found highly effective for endotoxin removal from aqueous solutions. Endotoxin removal by this adsorbent is greatly enhanced by the addition of an electrolyte, such as NaCl or Tris-HCl. The electrophoretic method has been used to study the mechanism of endotoxin adsorption. In many cases, adding the electrolyte increases the magnitude of negative zeta potential of the adsorbent in water, while endotoxin adsorption reduces the magnitude. It is hypothesized that ion-exchange between monovalent cations from the aqueous phase and Ca2+ ions near the surface of the adsorbent shift zeta potential of the adsorbent to the more negative direction. It is further hypothesized that endotoxins form cationic species through binding between its phosphate groups and Ca2+ ions dissolved from the adsorbent. The adsorption of endotoxins in the form of cationic species is enhanced by the increased negative zeta potential of the adsorbent when an electrolyte is added.
先进矿物公司生产的一种合成的一次性水合硅酸钙晶体吸附剂LRA产品，已被发现对从水溶液中去除内毒素非常有效。通过添加电解质（如氯化钠或三羟甲基氨基甲烷盐酸盐），这种吸附剂去除内毒素的效果会大大增强。电泳法已被用于研究内毒素吸附的机制。在许多情况下，添加电解质会增加吸附剂在水中的负ζ电位的幅度，而内毒素吸附则会降低该幅度。据推测，水相中的单价阳离子与吸附剂表面附近的Ca2+离子之间的离子交换会使吸附剂的ζ电位向更负的方向移动。进一步推测，内毒素通过其磷酸基团与从吸附剂溶解的Ca2+离子之间的结合形成阳离子物种。当添加电解质时，吸附剂增加的负ζ电位会增强阳离子形式的内毒素的吸附。
