Istituto di Chimica Agraria ed Ambientale, Universita Cattolica del Sacro Cuore, Piacenza, Italy.
J Environ Sci Health B. 2009 Aug;44(6):525-32. doi: 10.1080/03601230902997543.
Sorption of three pesticides (chlorpyrifos, metalaxyl and penconazole) has been measured on a commercial clay montmorillonite and on the same mineral modified with either of two cationic-surfactant micelles. Both micelle-clay complexes, commercial names Cloisite 20A and Cloisite 30B, showed a good capacity to sorb all three pesticides from water, whereas their sorption on the natural montmorillonite was not described by an isotherm. Modelling sorption on both micelle-clay complexes showed that the Freundlich sorption constant (K(F)) was higher for chlorpyrifos on Cloisite 20A (K(F) = 7.76) than on Cloisite 30B (K(F) = 5.91), whereas the sorption of metalaxyl was stronger on Cloisite 30B (K(F) = 1.07) than on Cloisite 20A (K(F) = 0.57). Moreover the micelle-clay complex Cloisite 20A also showed a good affinity for penconazole, the maximum quantity adsorbed (q(m)) of 6.33 mg g(-1) being 45% more than that on Cloisite 30B. Single-batch adsorption of each pesticide onto both micelle-clay complexes was studied using the Freundlich isotherm for chlorpyrifos and metalaxyl and the Langmuir isotherm for penconazole. The Cloisite 20A micelle-clay complex was predicted to require 23% less adsorbent to treat certain volumes of wastewater containing 30 mg L(-1) chlorpyrifos, 43% more to treat metalaxyl similarly and 57% less to treat penconazole compared with Cloisite 30B.
三种农药（毒死蜱、甲霜灵和丙环唑）在商业粘土蒙脱石和两种阳离子表面活性剂胶束改性的相同矿物上的吸附已被测量。两种胶束-粘土复合物，商品名 Cloisite 20A 和 Cloisite 30B，都显示出从水中吸附所有三种农药的良好能力，而它们在天然蒙脱石上的吸附不能用等温线来描述。对两种胶束-粘土复合物的吸附模型表明，毒死蜱在 Cloisite 20A 上的 Freundlich 吸附常数（K(F)）（K(F) = 7.76）高于 Cloisite 30B（K(F) = 5.91），而甲霜灵的吸附更强 Cloisite 30B（K(F) = 1.07）比 Cloisite 20A（K(F) = 0.57）。此外，胶束-粘土复合物 Cloisite 20A 对丙环唑也表现出良好的亲和力，最大吸附量（q(m)）为 6.33mg g(-1)，比 Cloisite 30B 多 45%。使用 Freundlich 等温线研究了每种农药在两种胶束-粘土复合物上的单次批量吸附，用于毒死蜱和甲霜灵，以及 Langmuir 等温线用于丙环唑。预测 Cloisite 20A 胶束-粘土复合物在处理含有 30mg L(-1)毒死蜱的特定体积废水时，需要的吸附剂减少 23%，处理甲霜灵时需要的吸附剂增加 43%，处理丙环唑时需要的吸附剂减少 57%，与 Cloisite 30B 相比。
