Endang Tri Wahyuni

Synthesis of Silver Nanoparticles Using o-Hydroxybenzoic, p-Hydroxybenzoic, and o,p-Dihydroxybenzoic Acids as Reducing Agents

Synthesis of silver nanoparticles (AgNPs) by reduction of AgNO3 with o-hydroxybenzoic, p-hydroxybenzoic and o,p-dihydroxybenzoic acids as reducing agents was investigated. This research was conducted to determine the effect of the position and number of hydroxyl groups towards the size, shape and stability of the resulted AgNPs. Surface Plasmon Resonance (SPR) of AgNPs was characterized by UV/Vis spectrophotometer, the shape and size of AgNPs was determined by Transmission Electron Microscope (TEM). The results showed that the reducing agent that has substituents in the para position (p-hydroxybenzoic acid) has the higher reduction ability than the others. AgNPs were yielded by all types of reducing agents in alkaline system. Reducing agents which have greater number of substituents (o,p-dihydroxybenzoic acid) could produce AgNPs with smaller concentration of AgNO3 than the others. AgNPs that was produced by reducing agent having substituents on the para position (p-hydroxybenzoic acid) was more stable and smaller particle size, i.e. 34 ± 1.78 nm than reducing agent that has substituent on the ortho para positions (with particle size 45 + 3.67 nm) and ortho positions (with particle size 70 ± 4.96 nm).

Zeolite Loaded Alginate Membrane for CO 2 and CH 4 Separation

Natural zeolite-incorporated alginate membranes were subjected for the gas separation of CO2 and CH4. High concentration of CO2 as biogas product can decrease the combution heat. Therefore, the membrane permeability and selectivity of CO2 and CH4 were investigated. The zeolite-incorporated alginate membranes were prepared using solution technique. The effects of zeolite on the performance and the thickness of membranes for gas separation were analyzed. The membranes were characterized by Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM), Brunaur Emmet Teller (BET) and Barret Joyner Hallenda (BJH).The result of permeability and selectivity show that membrane can flow CO2 and resist CH4. CO2 permeability increased simultaneously with an increase of zeolite content in the polymer matrix. The thickness of membrane influenced the flux of CO2 gas. CO2 Permeability increased simultaneously with a decrease of membrane thickness. The membrane containing rasio of mass alginate:zeolite 10:2 and thickness of 0.1267 mm shows the best permeability. According BJH result, pore diameter of membrane is 3.64 Å, while kinetic diameter of CO2 is 3.30Å and kinetic diameter of CH4 is 3.80Å. This was explained performance of membrane was molecular sieving.

Conversion of Green House CO 2 Gas into Useful Hydrocarbon Gasses by Photoreduction Method over TiO 2 /SiO 2 from Volcanic Ash

In order to decrease CO2 level, converting the gas into hydrocarbon fuel gasses has been performed by using photoreduction method under TiO2/SiO2 photocatalysis. The silica (SiO2) for TiO2/SiO2 preparation was purified from volcanic ash, that mixed with TiO2 suspended in water. The photoreduction process of CO2 was carried out in a batch technique, by exposing CO2 and water vapor in the presence of TiO2/SiO2 photocatalyst with UV lamp for 24 h. The gasses produced from the photoreduction were determined by gas chromatography method. In the research, the effects of HCl and HNO3 as hydrogen ion supplier were also evaluated. The research results indicate that the photoreduction of CO2 with the water vapor over the photocatalyst of TiO2/SiO2-volcanic ash has successfully produced methane and ethylene as fuel gasses, while in the presence of TiO2 no ethylene was resulted. The methane produced by TiO2/SiO2 was observed to be larger than by TiO2 powder. The content of TiO2 in TiO2/SiO2 with low level strongly influenced the yield of the products. In contrast, the yield was independent on the TiO2 content in high level. The presence of the acids was found to increase the methane produced , and no ethylene was formed, but instead, methanol was resulted. The effect of HCl was higher than HNO3.

Preparation of TiO2 photocatalyst with the matrix of palm wood (Arenga pinnata) waste in the photodegradation of batik wastewater

The study aimed to the preparation of TiO2 photocatalyst with the matrix from palm wood waste whose has lignin and cellulose content. TiO2 photocatalyst with the matrix from the wastewater of palm wood waste (TiO2/pww) was used as photocatalyst in photodegradation of batik wastewater. TiO2 solid was dissolved in ethanol and aquadest, added with the powder of wood palm waste and stirred with a magnetic stirrer for 16 hours. Then separation was carried out using buchner and filtrate and residue were obtained. The filtrate was disposed and the residue was calcined with various temperatures for 3 hours. The temperatures in this research were 100 °C (TiO2/pww-100); 200°C (TiO2/pww-200); 300°C (TiO2/pww-300). Analysis and characterization of TiO2/wwp were conducted using X-ray diffraction (XRD) and spectrophotometer Fourier Transform Infra Red (FTIR) methods. Photocalalytic TiO2/wwp use the batch system in a reactor with UV light 40 watts, 220 volts and length wave 360 nm the plate magnetic stirrer. Liquid waste batik adds TiO2/wwp with time variation. At XRD analysis showed that the preparation of TiO2/pww could be done on the heating TiO2/pww temperature of 100°C and 200°C. At the temperature of 300°C, it was indicated that the lignocelluloses in palm wood waste were burned, meaning that few lignocelluloses remained. The result of FTIR analysis showed clearly that at the temperature of 300°C, a few spectrum of lignocelluloses remained in palm wood waste, while at a temperature of 100°C and 200°C, spectra of lignocelluloses of palm wood waste remained. The result of photocatalysis test indicated that TiO2/pww could reduce 40%, 72%, 81% and 64% COD for TiO2 (control), TiO2/pww-100, TiO2/pww-200 and TiO2/pww-300, respectively.

Distribution of Detergent Waste in the Environment and the Removal by Using Photocatalytic Degradation and Coagulation Methods

Aims: This study is aimed to determine the distribution of detergent contamination in the Code River and the ability to remove it from laundry wastewater samples by using photocatalytic degradation and co agulation methods. Place and Duration of Study:The study was located at the Code River close to Gadjah Mada University, Yogyakarta, and the research was conducted for 6 months (June November 2013). Methodology: The water samples used in this study consist of waste water (produced from laundry activities) and river water (before and after the outlet of laundry waste disposal). Analysis of anionic surfactant and phosphate were carried out by UV/visible spectrophotometric methods using methylene blue and ammonium molybdate, respectively as complexing agents. The surfactant removal was studied using photocatalytic degradation and that of phosphate by coagulation methods. The photocataltyic reaction was carried out in batch technique by irradiating the artificia l waste in the presence of TiO 2 OriginalResearch Article

SYNTHESIS AND CHARACTERIZATION OF MESOPOROUS ALUMINOSILICATES Al-MCM- 41 AND INVESTIGATION OF ITS THERMAL, HYDROTHERMAL AND ACIDITY STABILITY

The synthesis and characterization of mesoporous aluminosilicates Al-MCM-41 and the investigation of its thermal, hydrothermal and acidity stability have been done. Al-MCM-41 were synthesized by hydrothermal method to the mixture of sodium silicate as Si source, aluminium hydroxide as Al source, sodium hydroxide as a solvent, and cethyltrimethylammoniumbromide (CTAB) as structure directing agent. The reaction were carried out in alkaline condition (pH = 10.2) at 383 K for about 24 h, followed by calcination at 723 K for about 10 h. The synthesized crystals were characterized using FTIR spectroscopy, X-ray diffraction and N2 fisisorption methods. The result showed that Al-MCM-41 sample with hexagonal structure was formed, it has a good in thermal and acid stability, but the structure disintegrated in an alkaline solution (pH = 10) and in boiled water.