Laboratório de Tecnologia e Desenvolvimento de Compósitos e Materiais Poliméricos (LaCoPol), Universidade Federal de Pelotas (UFPel), Campus Capão do Leão s/n, 96010-900 Pelotas, RS, Brazil.
Laboratório de Sólidos Inorgânicos (Lasir), Universidade Federal de Pelotas (UFPel), Campus Capão do Leão s/n, 96010-900 Pelotas, RS, Brazil.
J Hazard Mater. 2021 Sep 15;418:126405. doi: 10.1016/j.jhazmat.2021.126405. Epub 2021 Jun 15.
Hydrogels are often claimed as optimal adsorbents for water treatment; however, their efficiency towards the removal of hydrophobic pollutants is still limited. As an alternative, hydrogels prepared from polymers functionalized with siliceous materials can overcome this issue. Here, a composite hydrogel (denoted as GEL-SBA15) was prepared using alginate grafted with mesoporous silica (SBA15) and poly(vinyl alcohol) for benzene and toluene adsorption from aqueous solutions. Adsorption studies demonstrated that a low dosage of GEL-SBA15 (10 mg) has a high adsorption capacity for benzene (1482.8 mg/g) and toluene (596.6 mg/g) under mild experimental conditions (pH 7.0, at 25 °C). Besides, the adsorption capacities of GEL-SBA15 for both pollutants were enhanced compared to the conventional hydrogel. Kinetic analysis showed that the adsorption of benzene and toluene follows a pseudo-second order model, while the experimental adsorption data were well-fitted by the Freundlich isotherm. According to this isotherm, the adsorption occurs via a collaborative process, and weak physical forces (π-π interactions, van der Waals and hydrophobic) are involved. Hence, the post-utilized GEL-SBA15 can be recycled and reused up to 6 times without losing adsorption performance. Although hydrogels are not common adsorbents for aromatic hydrocarbons, the results reported here rank GEL-SBA15 as a promising adsorbent for the removal of these pollutants from water.
水凝胶通常被认为是水处理的最佳吸附剂；然而，它们对疏水性污染物的去除效率仍然有限。作为替代方案，用功能化硅材料的聚合物制备的水凝胶可以克服这个问题。在这里，使用接枝有介孔硅（SBA15）的海藻酸钠和聚乙烯醇制备了一种复合水凝胶（表示为 GEL-SBA15），用于从水溶液中吸附苯和甲苯。吸附研究表明，在温和的实验条件下（pH 7.0，25°C），低剂量的 GEL-SBA15（10mg）对苯（1482.8mg/g）和甲苯（596.6mg/g）具有高吸附容量。此外，与传统水凝胶相比，GEL-SBA15 对两种污染物的吸附容量都有所提高。动力学分析表明，苯和甲苯的吸附遵循准二级动力学模型，而实验吸附数据很好地符合 Freundlich 等温线。根据该等温线，吸附是通过协同过程发生的，涉及较弱的物理力（π-π 相互作用、范德华力和疏水力）。因此，使用后的 GEL-SBA15 可以回收并重复使用多达 6 次而不会失去吸附性能。尽管水凝胶不是芳烃的常见吸附剂，但这里报道的结果将 GEL-SBA15 列为一种有前途的吸附剂，可用于从水中去除这些污染物。
