Chemistry Department, Sciences and Technology School, University of Évora, Rua Romão Ramalho 59, 7000-671 Évora, Portugal; MARE-Marine and Environmental Sciences Centre, Institute for Advanced Studies and Research, University of Évora, Rua Romão Ramalho 59, 7000-671 Évora, Portugal.
Chemistry Department, Sciences and Technology School, University of Évora, Rua Romão Ramalho 59, 7000-671 Évora, Portugal.
J Hazard Mater. 2017 Feb 5;323(Pt A):575-583. doi: 10.1016/j.jhazmat.2016.05.091. Epub 2016 Jun 1.
Pharmaceutical residues presence in the environment is among nowadays top emergent environmental issues. For removal of such pollutants, adsorption is a generally efficient process that can be complementary to conventional treatment. Research of cheap, widely available adsorbents may make this process economically attractive. The aim of the present work was to evaluate the capacity of two clay materials (exfoliated vermiculite, LECA) to adsorb gemfibrozil, mefenamic acid and naproxen in lab-scale batch assays. Results show that both adsorbents are able to remove the pharmaceuticals from aqueous medium. Although vermiculite exhibited higher adsorption capacities per unit mass of adsorbent, LECA yielded higher absolute removals of the pharmaceuticals due to the larger mass of adsorbent. Quantum chemistry calculations predicted that the forms of binding of the three molecules to the vermiculite surface are essentially identical, but the adsorption isotherm of naproxen differs substantially from the other two's. The linear forms of the latter impose limits at lower concentrations to the removal efficiencies of these pharmaceuticals by vermiculite, thereby electing LECA as more efficient. Notwithstanding, vermiculite's high specific adsorption capacity and also its much faster adsorption kinetics suggest that there may be some benefits in combining both materials as a composite adsorbent solution.
药品残留存在于环境中是当今最主要的环境问题之一。为了去除这些污染物，吸附是一种通常有效的方法，可以作为传统处理方法的补充。研究廉价、广泛可用的吸附剂可以使这一过程在经济上具有吸引力。本工作的目的是评估两种粘土材料（膨胀蛭石、LECA）在实验室规模批式实验中吸附吉非贝齐、甲芬那酸和萘普生的能力。结果表明，两种吸附剂都能从水溶液中去除这些药物。虽然蛭石表现出更高的单位质量吸附剂的吸附容量，但由于吸附剂的质量较大，LECA 对药物的绝对去除率更高。量子化学计算预测，这三种分子与蛭石表面的结合形式基本相同，但萘普生的吸附等温线与其他两种药物的吸附等温线有很大的不同。后两者的线性形式在较低浓度下限制了蛭石对这些药物的去除效率，因此 LECA 更为有效。然而，蛭石具有较高的比吸附容量，以及更快的吸附动力学，这表明将这两种材料组合成一种复合吸附剂溶液可能会有一些好处。
