Durán Esperanza, Bueno Salvador, Hermosín M Carmen, Cox Lucía, Gámiz Beatriz
Instituto de Recursos Naturales y Agrobiología (IRNAS), CSIC, Avda. Reina Mercedes n°10, 41012 Sevilla, Spain.
Fundación Innovarcilla, Pol. Ind. El Cruce. C. Los Alamillos, n° 25, 23710 Bailén, Jaén, Spain.
Sci Total Environ. 2019 Jul 1;672:743-751. doi: 10.1016/j.scitotenv.2019.04.014. Epub 2019 Apr 3.
A local low value bentonite from Southern Spain (Raw Bentonite), previously decarbonated (Bent), was modified to improve its pesticide adsorption capacity with Fe, hexadecyltrimethylammonium (HDTMA) and the biopolymer chitosan (CH). Adsorption of pesticides on powdered samples showed that Fe and HDTMA were appropriate modifiers for this purpose. The modification was optimized by saturation with Fe (Bent-Fe) and hexadecyltrimethylammonium (Bent-HDTMA) and the obtained adsorbents were characterized by several physicochemical techniques (X-ray diffraction, thermogravimetric analysis, X-ray fluorescence, physisorption of N). Their adsorption capacity to remove three widely used pesticides in Andalusian crops (terbuthylazine, tebuconazole and MCPA) from water was assessed and compared with the commercial organoclay Cloisite® 10A (Clo10). The modified bentonites adsorbed the selected pesticides in a percentage ranging from 30 to 100%, whereas sorption on Clo10 ranged from 30 to 90%. For their possible use as filtering beds, Bent-HDTMA, Bent-Fe and Clo10 were granulated by using three different binders (colophony resin and carnauba and bee waxes) at three different mixing ratios and the water resistance and pesticide adsorption of the granules were measured. Results showed that the granulation process did not alter the pesticide adsorption capacity of the powdered modified bentonites, and both waxes granules (carnauba and bee wax) showed better behavior than resin granules. In this work, we succeeded in the preparation of granulated adsorbents derived from a low cost material with similar behavior against a high purity smectite (precursor of Cloisite® 10A). This raises an alternative for this waste material to be used in filter systems for removing pesticides from contaminated water.
来自西班牙南部的一种当地低价值膨润土（原膨润土），之前已脱碳（膨润土），用铁、十六烷基三甲基氯化铵（HDTMA）和生物聚合物壳聚糖（CH）进行改性，以提高其农药吸附能力。农药在粉末样品上的吸附表明，铁和HDTMA是用于此目的的合适改性剂。通过用铁（膨润土 - 铁）和十六烷基三甲基氯化铵（膨润土 - HDTMA）饱和对改性进行了优化，并且通过几种物理化学技术（X射线衍射、热重分析、X射线荧光、N的物理吸附）对所得吸附剂进行了表征。评估了它们从水中去除安达卢西亚作物中广泛使用的三种农药（特丁津、戊唑醇和灭草松）的吸附能力，并与商业有机粘土Cloisite® 10A（Clo10）进行了比较。改性膨润土对所选农药的吸附百分比范围为30%至100%，而在Clo10上的吸附范围为30%至90%。为了它们可能用作过滤床，使用三种不同的粘合剂（松香树脂、巴西棕榈蜡和蜂蜡）以三种不同的混合比例将膨润土 - HDTMA、膨润土 - 铁和Clo10制成颗粒，并测量了颗粒的耐水性和农药吸附性。结果表明，造粒过程没有改变粉末状改性膨润土的农药吸附能力，并且两种蜡颗粒（巴西棕榈蜡和蜂蜡）表现出比树脂颗粒更好的性能。在这项工作中，我们成功地制备了由低成本材料衍生的颗粒状吸附剂，其性能与高纯度蒙脱石（Cloisite® 10A的前体）相似。这为这种废料用于从受污染水中去除农药的过滤系统提供了一种替代方案。
