No abstract

The structure of graphite oxide and graphene oxide (GO) has been studied previously using various analyses and computer simulations. Although some oxygen functional groups (OFGs) are accepted as the main functionalities in GO, the structure of GO has remained elusive. In this regard, GO was produced using the modified Hummers method and was investigated using X-ray diffraction pattern, Fourier transform infrared analysis and Boehm titration method. Based on the obtained results, a modified model was proposed for GO based on the model of Lerf-Klinowski. OFGs include highly carboxyl groups and phenols with few epoxides, lactones and ketones agglomerated in some regions due to hydrogen bonding between functional groups. Trapped water molecules were shown between the GO sheets which strongly affected the distribution of OFGs and their aggregation by hydrogen bonding.

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The aim of this study was to investigate the effect of tartrate ion (C4H4O6 2-) on the extraction and separation of zinc and cadmium using D2EHPA extractant. The presence of tartrate ion in the solution caused the shift of the extraction curve of zinc and cadmium to the more alkaline pH; however, the shifting rate for the cadmium extraction curve was more significant. In the absence of tartrate ion, ΔpH50% value was equal to 0.65. If 0.2 M tartrate ion were added to the aqueous phase, ΔpH50% value would increase to 1.09. The FT-IR analysis of organic phase showed that tartrate ion absorbed the organic phase along with zinc and cadmium. "Slope analysis method" also showed that 0.25 M and 0.5 M tartrate ion participated in the zinc-tartrate and cadmium-tartrate complex formation, respectively; however, extraction number was changed with increasing the tartrate ion concentration.