The effect of increasing surface area of graphite electrode on the performance of dual chamber Microbial Fuel Cells (MFC) was observed. The surface area of graphite electrode (anode and cathode) that was using in this experiment was 29.5cm2 and 44.5cm2 for the A and B reactor, respectively. The anode chamber contained mixed microorganism culture from real wastewater of textile industry and the cathode chamber contained 0.1M potassium permanganate electrolyte solution. The salt bridge was required to stabilize the charge between the anode and cathode chambers, and the electrodes attached to the anode and cathode chambers as the electron catcher. Both, the A and B reactor were observed for 72 hours of running time. The voltage and power density were found to increase with the increase in surface area of the graphite electrode. The highest power density was 93.93mWm-2 and 197.23mWm-2 that obtained at 36 hours and 48 hours on the A and B reactor, respectively. At the end of experiment, these MFCs system could also reduce COD by 28.6% and 15.6% on A and B reactor, respectively.

Effect of aeration treatment on Methylene Blue (MB) removal using TiO2-Zeolite has been investigated. The TiO2-Zeolite was prepared by mixing activated zeolite and TiO2 in absolute ethanol. This composite was characterized using Fourier Transform Infrared (FT-IR) and X-Ray Diffraction (XRD). The MB removal was monitored spectrophotometrically. The effect of contact time, composite mass, and aeration treatment on MB removal was observed. Characterization results showed that there was interaction between TiO2 and SiO/AlO of zeolite. The observation of aeration treatment using oxygen exhibited significant improving on MB removal.

The effect of residence time of graphitisation on thermal conductivity of molded graphite has been examined. The examination has been conducted by varying residence time of graphitisation of molded carbon with petroleum coke as raw material and coal tar pitch. Graphitisation has been conducted by heating molded graphite at 2500 °C in argon atmosphere with residention time of 10, 30 and 90 minutes. Graphitisation degree, density, shrinking mass and porosity of molded graphite were examined and so was its thermal conductivity. The result showed that the decrease of porosity and the increase of graphitisation degree due to the increasing of residention time of graphitisation will increase the thermal conductivity of graphite. Molded graphite graphitisized with residence time for 90 minutes residention time gave thermal conductivity of 2.134 Watt/mK and graphitization degree 0.718.

Abstrak (60, 75, 90, 105, 120, and 135 minutes, respectively) and initial concentration (10, 20, 40, 60, 80, 90, and 100 ppm, respectively)

Telah dilakukan sintesis silika gel dari abu ampas tebu yang berasal dari pabrik gula Madukismo Yogyakarta, menggunakan natrium hidroksida dan larutan pembentuk gel asam klorida. Tujuan penelitian ini adalah untuk mengetahui kesetimbangan isotermis adsorpsi dan efektifitas desorpsi silika gel terhadap paraquat diklorida. Sintesis dilakukan dengan pengabuan ampas tebu pada temperatur 700°C selama 4 jam. Abu ampas tebu dilarutkan dengan larutan natrium hidroksida untuk menghasilkan natrium silikat, sedangkan pembentukan gel dilakukan melalui penambahan HCl. Hasil penelitian yang didapat menunjukkan bahwa silika gel hasil sintesis memiliki luas permukaan 43,442 m2/g, volum pori 0,151 cc/g, dan diameter pori 15,223 Å. Kesetimbangan isotermis adsorpsi dimungkinkan mengikuti model kesetimbangan Freundlich dengan nilai R2 = 0,994. Persamaan kesetimbangan Freundlich silika gel hasil sintesis adalah qe (0,2) = 3,11 Ce 3,388. Efektifitas desorpsi diperoleh dengan menggunakan agen pendesorpsi NaOH.