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The superior ability of graphene has attracted much interest in both its development and application in various field. Graphene has been developed as material for a precursor for fabricating transparent conductive films, absorbents for environmental application, filler or additive in bioplastics, and many other applications. Graphene can be generated from carbon-based materials such as wood charcoal, sawdust, coconut shells, bagasse, rice husk, old tires, polymer-based waste, and cellulose. In this research, graphene is synthesized via Hummers route using carbon of sugarcane bagasse as raw materials. Parameter such as various addition of KMnO4 (5,10,15 gr) is observed. The characterization of the graphene such as X-Ray Diffraction (XRD), Fourier transform infra-red (FTIR) and scanning electron microscope (SEM) were used to investigate the different implication of the parameter applied during the production process. The results show that the graphene-like materials exhibit similar characteristics as published in previous works in term of crystalline structures, morphology, and its chemical bonding characteristics which can be used for diverse application as demonstrates by graphene derived from graphite exfoliation followed by reduction.

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TiO2 nanoparticles, a semiconductor photocatalyst is widely used in various applications especially for water treatment. The common problems for the application are separating the nanoparticles from the water body and recovering it to be reused. This research was conducted to investigate the aggregation and sedimentation properties of TiO2 nanoparticles via chemical addition. The experiment was carried out for 5 hours by varying the pH, ionic strength, and the addition of organic matter such as rhodamine B, methylene orange, and humic acid. The results indicate that pH and ionic strength greatly affect the TiO2 sedimentation process. Sedimentation can be formed properly when the solution is at pH 1 and 14, this happens because pH is close to the isoelectric point. Meanwhile, ionic strength with a concentration of 0.1 M gave the most optimal results in TiO2 sedimentation. In the presence of ionic strength with the appropriate concentration, the thickness of the electrical double layer particles can be reduced so the attractive force increases and sedimentation occur. Meanwhile, in the presence of organic matter, rhodamine B, methylene orange, and humic acid did not significantly affect the formation of TiO2 sedimentation.Keywords: titanium dioxide, sedimentation, ionic strength, isoelectric point, water treatment

Since the water splitting breakthrough using semiconductor reported in 1972, titanium dioxide (TiO2) has been extensively investigated as a promising material used in broad range of research areas. TiO2 is a transition metal oxide semiconductor with three distinct polymorph crystalline structures. With that alone TiO2 established remarkable performance as photocatalyst for organic photodegradation in the irradiation of UV. However, improvement on the light absorption properties that support the excellent photocatalytic activity still needs to be pursued for wider environmental application. In this book chapter, the limitations of TiO2 as photocatalyst were discussed especially in the industrial wastewater treatment application. The strategies in overcoming the limitation by TiO2 morphology and surface modification were also presented. The modified TiO2 nanomaterials proves to have excellent photocatalytic activity in dyes (Rhodamine B, Methyl Orange and Methylene Blue) as representative of organic pollutant degradation and Cu (II) reduction as representative of inorganic pollutant.