摘要

       在本研究中，系统研究了氧化石墨烯 (GO) 纳米片对具有两种不同分子结构的四种典型 ARG（即环状（c）-和双链（ds）-ARG）的去除效率和机制。在 300 μg/mL GO 溶液中，四个 ARG 对 c-ARG 的平均去除率高达 3.11 个对数，对 ds-ARG 的平均去除率高达 2.88 个对数。吸附数据符合Freundlich等温线和准二级动力学模型。 c-ARGs 和 ds-ARGs 都可以在 15 分钟内获得表观吸附平衡，表明 GO 的有效去除。自由能参数表明去除过程是放热和自发的。遗传分子结构的结构差异可能是去除差异的原因。此外，还研究了包含初始 ARG 浓度、pH 值和离子种类的几个去除因素。拉曼光谱、漫反射红外傅立叶变换光谱 (DRIFTs) 和电化学分析结果表明，GO 对 ARGs 的吸附主要归因于 GO 纳米片的含氧基团和 π 键系统，导致与芳香族化合物的化学结合。核酸和强 π 堆积相互作用。此外，对真实水样进行了详细的验证测试，可以从天然水样中去除 80% 的 ARG。因此，将 GO 纳米片作为一种新型吸附剂用于有效处理 ARG 污染水将具有巨大的潜力。

       In this study, removal efficiency and mechanism of four typical ARGs with two different molecular structures (i.e., cyclic (c)- and double-stranded (ds)-ARGs) by graphene oxide (GO) nanosheet were systematically investigated. The average removal of four ARGs was as high as 3.11 logs toward c-ARGs and 2.88 logs toward ds-ARGs at 300 μg/mL GO solution. The data of adsorption were fitted well with Freundlich isotherm and pseudo-second-order kinetic model. The apparent adsorption equilibrium can be obtained within 15 mins for both c-ARGs and ds-ARGs, indicating the effective removal by GO. The free-energy parameters demonstrated that the removal processes were exothermic and spontaneous. The structural differences of genetic molecular structures can be responsible for the removal discrepancy. Moreover, several removal factors containing initial ARGs concentration, pH and ion species were also investigated. The results of Raman spectra, Diffuse Reflectance Infrared Fourier Transform spectroscopy (DRIFTs) and electrochemical analysis indicated that the adsorption of ARGs by GO was mainly attributed to the oxygen containing groups and π-bonding system of GO nanosheet, which resulted in chemical binding with aromatic nucleic acid and strongly π-stacking interactions. Furthermore, a detailed verification test of real water samples was conducted and 80% of the ARGs can be removed from a natural water sample. As a result, it would be great potential to apply GO nanosheet as a novel adsorbent for effective treatment of ARG-contaminated waters.

https://www.sciencedirect.com/science/article/abs/pii/S1385894716315182