Candra Purnawan

Visible light photoelectrocatalytic degradation of rhodamine B using a dye-sensitised TiO2 electrode

Titanium dioxide is a promising catalyst for application in the photodegradation of organic pollutants in water due to its powerful oxidising property and long-term photostability. This study presents the production of titanium dioxide using the sol-gel process, dye sensitisation of the TiO2 electrode, and the performance of that cell. Sensitisation of titanium dioxide was performed using a dye, i.e., Fe(II)-polypyridyl complexes. The photoelectrocatalytic degradation of rhodamine B (RB) using ITO/TiO2/dye as electrode was investigated via a series of potentials, from +1.0 V to −1.0 V, and at various pH and NaCl concentration values (ITO is indium tin oxide conductive glass). The photoelectrocatalytic degradation of RB was performed with a visible light lamp. The change in the absorbance of RB with various potentials indicated that the absorbance of RB in solution systems with the sensitised TiO2 electrodes decreased with increasing anodic potential bias. The degradation cell exhibited better performance when the positive anodic bias was applied. The pH values of RB in solution systems also influence the photoelectrodegradation process because of the different RB species present. NaCl concentration also affects the activity of RB photoelectrocatalytic degradation due to changes in the ionic strength character of the electrolyte.

Photocatalytic and Photoelectrocatalytic Degradation of Methyl Violet Using Graphite/PbTiO3 Composite

Photocatalytic and photoelectrocatalytic degradation of Methyl Violet dye using Graphite/PbTiO 3 composites has been conducted. The purposes of this research were to synthesis the Graphite/PbTiO 3 composite electrode and determine its effectiveness on Methyl Violet degradation. Synthesis of Graphite/PbTiO 3 composite was successfully performed via sol-gel method by mixing graphite powder, titanium tetra isopropoxide precursor solution (TTIP) and Pb(NO 3 ) 2 . The Graphite/PbTiO 3 composites were characterized using X-Ray Diffraction (XRD), Fourier Transform-Infra Red (FT-IR) and Scanning Electron Microscopy (SEM). The XRD diffractogram and IR spectrum of Graphite/PbTiO 3 composite revealed all characteristic peak of graphite and PbTiO 3 . Photocatalytic degradation process showed that Graphite/PbTiO 3 composite decreased concentrations of Methyl Violet up to 92.20%. While photoelectrocatalytic degradation processed for 30 minutes at neutral pH and 10 V voltage degraded the Methyl Violet until 94%.

The Effects of plasticizers and palmitic acid toward the properties of the carrageenan Film

Varied plasticizers and palmitic acid additive have been added in the carrageenan film. The film was made by mixing of the carrageenan and plasticizers (glycerol, polyethylene glycol, polyvinyl alcohol) with composition of 92:3, 90:6, 87:9, 84:12, 81:15(%w/w) and in the presence of palmitic acid as additive with 1%, 2%, 3%, 4%, 5% of total weight. Casting method was used for the film molding and drying at 60oC with the oven for 12 hours. To investigate the effects of plasticizers and additive, some mechanical tests on film were performed. The test result concludes that plasticizers in the film decreased the tensile strength and increased the elongation break of the carrageenan film. The additive of palmitic acid decreased the tensile strength of the carrageenan film and also decreased the-the water absorbance of the film. The highest tensile strength of films made was with the formulation of carrageenan: PEG with composition of 92:3 (% w/w). The highest elongation break of the film was for carrageenan:PVA with the composition of 81: 15 (%w/w) and carrageenan:palmitic acid:PEG with the composition of 92: 3: 1 (%w/w). The lowest water absorption of the film was achieved for carrageenan:PVA:palmitic acid with the composition of 87: 3: 5 (%w/w).

Development of inorganic composite material based TiO2 for environmental application

Syntheses of various materials, for green energy nanotechnology applications have special attention to develop emerging areas, such as environmental as well as energy materials. Various approaches for preparing nanostructured photocatalysts, such as titanium dioxide, nickel oxide, lead oxide and their composites, was introduced. The use of nanomaterials as photocatalysts water detoxification by visible light photocatalyst of an inorganic composite as well as dye-sensitized photoreduction was also discussed. The enhancement of selective photocatalyst system was gain by the use of photocatalyst composite materials and applied potential bias on the system. The photoelectrocatalytic degradation of rhodamine B (RB) and Remazol Yellow FG (RY) as water contaminant using the thin film of modified TiO2 as the electrode was investigated via a series of potentials, and various pH. The result showed that the anodic potential bias influenced the degradation rate of water contaminant and exhibited better performance by the positive anodic bias was applied. The pH conditions influence the active dye structure whereas it will interact with inorganic semiconductor photocatalyst. Using dye- sensitized TiO2 system (DSTs), we have applied this system to build water decolorization as a novelty environmental remediation system.