Department of Chemistry, Quaid-i-Azam University, Islamabad, 45320, Pakistan.
Department of Chemistry, University of Wah, Quaid Avenue, Wah Cantt, 47040, Pakistan.
J Environ Manage. 2019 Jan 15;230:199-211. doi: 10.1016/j.jenvman.2018.09.061. Epub 2018 Oct 1.
Here in, we presented a facile one-step method for the synthesis of Graphene oxide-silver (GO-Ag) nanocomposite and its applications as a sorbent for the elimination of some toxic pollutants from aqueous medium, as an efficient catalyst in the individual as well as simultaneous reduction reactions of multiple compounds, and as an antibacterial agent for the destruction of some harmful microorganisms existent in wastewater. GO was prepared using a modified Hummers method and Ag nanoparticles were integrated on GO sheets by chemical reduction of Ag ions on the surfaces of GO sheets. The composition and morphology of the nanocomposite was extensively characterized with elemental dispersive X-ray analysis (EDX), Fourier transform infra-red (FT-IR) spectroscopy, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). The GO-Ag nanocomposite demonstrated remarkable adsorption capacities and recyclability for malachite green (MG) and ethyl violet (EV) dyes. Various experimental parameters affecting adsorptive behavior of nanocomposite like temperature, pH, time of contact between dye and adsorbent, and adsorbent dose were evaluated thoroughly. Experimental data was simulated with different adsorption isotherms and kinetic models to evaluate adsorption behavior of both dyes and results confirmed the adsorption of both the dyes to be followed by pseudo 2nd order kinetic model and Langmuir adsorption model. Moreover, adsorbent was regenerated in suitable media for both dyes without any loss in removal efficiency. The catalytic performance for the 2-nitroaniline (2-NA) reduction was investigated in detail. Most importantly, the prepared nanocomposite was found to have potential to adsorb multiple pollutants all together as well as to catalyze the simultaneous reduction of a mixture of dyes (MG, MO, and EV) and 2-NA. An additional advantage of the GO-Ag nanocomposite was its antibacterial activity acquired to the presence of Ag nanoparticles. Two bacterial strains (Gram-negative bacterium, E. coli and the Gram-positive bacterium, S. aureus) were used to test antibacterial activity of composite and the results confirmed the remarkable performance of the nanocomposite in destroying harmful pathogens.
在这里，我们提出了一种简便的一步法合成氧化石墨烯-银（GO-Ag）纳米复合材料，并将其应用于从水溶液中去除一些有毒污染物的吸附剂、作为单个和同时还原多种化合物的有效催化剂，以及作为破坏废水中存在的一些有害微生物的抗菌剂。GO 是通过改良的 Hummers 法制备的，Ag 纳米粒子通过化学还原 GO 片表面上的 Ag 离子集成在 GO 片上。纳米复合材料的组成和形态通过元素分散 X 射线分析（EDX）、傅里叶变换红外（FT-IR）光谱、透射电子显微镜（TEM）、场发射扫描电子显微镜（FESEM）、X 射线衍射（XRD）和热重分析（TGA）进行了广泛的表征。GO-Ag 纳米复合材料对孔雀石绿（MG）和乙基紫（EV）染料表现出显著的吸附能力和可回收性。详细评估了影响纳米复合材料吸附行为的各种实验参数，如温度、pH、染料与吸附剂接触时间和吸附剂剂量。实验数据通过不同的吸附等温线和动力学模型进行模拟，以评估两种染料的吸附行为，结果证实两种染料的吸附均遵循准二级动力学模型和 Langmuir 吸附模型。此外，在不降低去除效率的情况下，在合适的介质中对吸附剂进行了再生。详细研究了 2-硝基苯胺（2-NA）还原的催化性能。最重要的是，所制备的纳米复合材料具有同时吸附多种污染物和催化混合染料（MG、MO 和 EV）和 2-NA 同时还原的潜力。GO-Ag 纳米复合材料的另一个优点是由于存在 Ag 纳米粒子而获得的抗菌活性。使用两种细菌菌株（革兰氏阴性菌大肠杆菌和革兰氏阳性菌金黄色葡萄球菌）测试了复合的抗菌活性，结果证实了纳米复合材料在破坏有害病原体方面的卓越性能。
