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Existence of many functional groups on graphene oxide sheets offers potential applications for the removal of environmental pollutants such as heavy metals and dyes. Moreover, materials with aligned porosity in the micrometer range could further enhance the adsorption capability by providing more adsorption sites. In this paper, the performance of graphene oxide aerogel (GOA) prepared by ice segregation induced self-assembly method was investigated as an adsorbent to remove methylene blue (MB) from aqueous solutions. The adsorbent was characterized by XRD, FTIR, TEM, SEM, EDX, and BET. The results showed that GOA has extremely high adsorption capacity for removal of MB. The equilibrium of MB removal process by GOA was well described by the Langmuir isotherm model, with a maximum adsorption capacity of 416.6667 mg g -1 . The results of the thermodynamic investigations indicated that the adsorption reactions were spontaneous (DG°\ 0), endothermic (DH°[ 0) and the adsorption kinetics of MB on GOA was best fitted to the pseudo-second-order model.

This paper reports the application of graphene oxide aerogels (GOAs) for adsorption of lead(II) ions from aqueous solutions. The aerogels were fabricated from graphene oxide (GO) colloidal suspensions by unidirectional freeze drying method. The synthesized GO powders, as well as the aerogels, were thoroughly characterized by various techniques. The experimental data showed that the kinetic of adsorption followed a pseudo-second-order model with sharp lead(II) ions uptake within the first 90 min. Kinetic data analysis revealed that the adsorption process was controlled by film diffusion mechanism. The equilibrium data were best fitted to Langmuir model and the qmax was calculated to be as high as 158 mg/g. Thermodynamic analysis demonstrated that the adsorption process was spontaneous and endothermic with increased randomness at the solid-liquid interface. Experiments showed that almost all the adsorbed ions could desorb into the solution only by decreasing the solution pH below the isoelectric point of the adsorbent. In addition to abundant oxygen containing functional groups existing on the surface of GO sheets, high porosity and surface area of the aerogel are believed to be influential factors in the adsorption process.

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In this research, the effect of heating on the mechanical alloying process for synthesizing of titanium carbide was investigated. Raw materials containing pure titanium and graphite powders were milled in different times and temperature. In order to detect phases and properties of synthesized materials X-ray diffraction was applied. Physical properties including density and specific surface area along with microstructure were studied. Results showed that heating can accelerate the mechanical alloying process. By increasing the temperature during milling, production mechanism of titanium carbide changed from self-propagating high-temperature synthesis to gradual model. Changes of density confirmed this phenomenon too. Increasing the milling time leads to particle size and crystal of synthesized titanium carbides became finer down to nanometer scale. Because of higher effective time span of produced titanium carbide, increasing the temperature produces finer particle sizes of powders in similar milling time.