چكيده به لاتين
With the fast development of nanotechnology, engineered nanomaterials will be inevitably released into the environment. One of the newest nanomaterials that have been used in widespread applications such as electronics, drug delivery, composites and etc. is called graphene oxide (GO). Increasing studies showed the toxicity of graphene oxide while exposed to the microbial community and human cells, which raise concerns over their fate and transport in the environments. Thus, in recent years, researchers have focused on the effect of these 2D nanomaterials in the environment. However, most of the conducted studies strictly investigate each factor independently without influencing other factors simultaneously.
One of the most important influential factors graphene oxides fate in the aqueous environment is the presence of solid particles such as clay minerals. In the present study, we will investigate the influential factors in the interaction of graphene oxide and clay minerals. The effect of pH, major cations (including monovalents like sodium and potassium, and divalents like calcium and magnesium), heavy metals and natural organic matters are studied through batch experiments by the means of measuring the UV-vis absorbance.
Our results show that the effect of pH on GO attachment on both clay minerals is fairly comparable in mild acidic solution. However, it is showed that there is a substantial decrease in the attachment of GO on kaolinite in mild alkaline solution, compared to montmorillonite. Regarding the major cations, the effect of divalent cations is much greater than the monovalents which is due to the bridging effect between clay mineral functional group and GO functional group. In addition, heavy metals indicate a severe effect on increasing the attachment of GO on clay minerals. For instance, 1mM of chromium could lead to the complete attachment of 40mg/l of GO on clay minerals. It is also shown that natural organic matters could only impact the attachment in presence of monovalents (sodium and potassium) and they are not able to hinder the attachment and overcome the strong chemical bonding caused by multivalents and/or heavy metals.
