Advanced Materials Research Vol. 917

Abstract: Separate hydrolysis and fermentation (SHF) is the common process in producing ethanol from lignocellulosic biomass. Nowadays, simultaneous saccharification and fermentation (SSF) process has been seen as potential process for producing ethanol with shortens process time with higher yield of ethanol. Hence, in the current work, the utilization of empty fruit bunches (EFB) in SSF process was studied. In order to improve saccharification reactivity of EFB, hydrothermal pretreatment at 180 and 220 °C was used to pretreat EFB. The findings showed that SSF has the potential in producing ethanol from EFB.

Abstract: The production of biodiesel from crude palm oil (CPO) using microwave technique is investigated and has been compared with conventional heating. Two-step biodiesel production process is applied to maximize the highest biodiesel yield in short reaction time using microwave method. Sulfuric acid (H2SO4) as acid catalysts is used in pre-treatment of feedstock by esterification process followed by potassium hydroxide (KOH) as base catalyst for transesterification process with low methanol to oil ratio. The main purpose of the pre-treatment process is to reduce the free fatty acids (FFA) content of CPO from higher value of FFA content (>6.8%) to a minimum level for biodiesel production (<1%). Esterification and transesterification is carried out in fully instrumented and controlled microwave reactor system to get higher yield in shorter time. This two-step esterification and transesterification process showed that the maximum conversion of palm biodiesel obtained is 95.1% with the process conditions of methanol-to-oil molar ratio of 6:1, reaction temperature 65oC, reaction time 15min, and 2% (wt/wt) KOH amount using microwave method compared to conventional heating where the palm oil methyl ester (POME) yield obtained is 81% at the same conditions. The result showed that, the biodiesel production using microwave technique proved to be a fast and easy route to get high yields of biodiesel.

Abstract: This experiment was performed to determine the ability of the coagulation performance of rambutan seed in comparison to alum for potential use in turbidity removal in water and wastewater treatment industry. Experiments were conducted to find the optimum operating conditions for coagulation process such as coagulant dosage and pH and also suitable extracting solvent for the active agent (distilled water, NaCl and NaOH). 1 M NaCl was found to be an effective solvent for extracting the active coagulant agent in rambutan seed and gave about 99 % turbidity removal. The optimum rambutan seed dosages and pH was 100 mg/l and pH 3, resulting in > 90% turbidity removal. In order to reduce dependency on alum, 50% alum and 50% rambutan seed as coagulant combination was used in the order of alum first followed by rambutan seed. The highest turbidity removal of 99% was achieved compared to when using alum (91%) and seed (88%) alone. Rambutan seed coagulant exhibited faster sedimentation time due to bigger flocs formation and also smaller sludge volume than alum. The results suggest potential of using rambutan biomass as biocoagulant. Keywords: rambutan seed, alum, protein, natural coagulant, turbidity, solvent

Abstract: Centella asiatica (C. Asiatica) contains asiatic acid as one of bioactive constituent that has the commercial medicinal value such as anticancer and also possess wound healing property. The ball milling process was carried out at 0.5, 4 and 8 hours. The effects of ball milling at different times were characterized using particles size analysis (Photon Correlation Spectroscopy) and Fourier Transform infra red (FTIR) Spectroscopy. The surface morphology was characterized by Field-Emission Scanning Electron Microscope (FESEM). As a result, smallest particles size by mean 279.5 nm was produced at a longest milling time (8 hr) and FTIR spectra shows there is no obvious change in the structure of C. asiatica nanopowders as compared to the micropowders. Centella asiatica nanopowders shows good extraction yield of asiatic acid with 5.5 μg/ml of yield but poor inhibition of DPPH as compared to micropowders.

Abstract: A series of organic-inorganic hybrids were developed via intercalation process of primary, secondary and tertiary ammonium cations into different alkali and alkaline earth and transition metal cation forms of bentonite clay to be used as adsorbent materials for CO₂ capture under ambient temperature and slightly high pressure. The effect of the molar mass of amines on the structural characteristics, surface properties and CO₂ loading capacity of bentonite clay were investigated by X-ray diffraction, Brunauer-Emmett-Teller method and Magnetic Suspension Balance equipment, respectively. X-ray diffraction results revealed that the basal spacing of bentonite clay after modification with amines was increased with the molar mass of amine used, while BET results showed an inverse effect of the molar mass of amines on the surface area of the synthesized materials. The CO₂ loading capacity of the examined samples revealed that bentonite clay modified with monoethanolammonium cations retained higher CO₂ amount compared to those modified with di-and triethanolammonium cations. CO₂ adsorption isotherms on MEA⁺-Mg-MMT were conducted at 298, 323 and 348 K and different pressures. A decrease in CO₂ uptake with increasing temperature was observed, suggesting the exothermic nature of the adsorption process.

Abstract: Petroleum sludge was solidified in ordinary Portland cement, and the leachability test was performed based on American Nuclear Society 16.1 to produce leachate. The organic in solidified sludge was extracted by micro solid extraction to determine the organic in the sample. Organic in the leachate sample was detected by solid phase micro extraction by head space polydimethyl siloxane fiber using gas chromatography mass spectrometry. The targeted organic compounds in solid sample and leachate were quantified by the benzene, toluene, ethyl benzene, xylene, naphthalene and phenanthrene standards. The organic compounds in solidified sludge consist of aliphatic and ester acid with long carbon chain of Carbon 15 to Carbon 64. The aliphatic group in the leachate was found at the reduced rate of about tenfold of the solid sample. Derivative leachate products mainly composed of cyclic siloxane compounds. The metals leachability in the acidic medium depends on the metal hydroxide solubility value. High lead mobility in the acidic medium was due to its high solubility induced the highest effective diffusion coefficient of 1.59 x 10^-07cm²/s.

Abstract: Removal of CO₂ had been one of the main issues facing in worldwide. Intensive researches are still going on to effectively reduce CO₂ at low cost. Physical absorption is one of the well-established technologies used to removal CO₂ from other gases. The physical absorption process is simple; whereby it contains only one gas liquid contactor and a series of flash tank to regenerate solvent. The CO₂ will be absorbed in the physical solvent in the high pressure gas liquid contactor and flashed out in the medium and low pressure flash tank. The advantage of using physical solvent is that the CO₂ is absorbed without any chemical reaction involved, thus it can be flashed out easily by reducing the pressure, passing inert gas through the solvent and mild thermal regeneration. The physical absorption is the best operated at high pressure and low temperature as the solubility of CO₂ in the solvent is high at the particular condition. Researches carried out currently are focusing on solvent development, absorption and desorption process development and mathematical modeling.

Abstract: The solubility of carbon dioxide (CO₂) was measured in (0.2, 0.4, 0.6 & 1.2) molars of aqueous solutions of Piperazine (PZ) at three temperatures (30, 40 and 60) °C. The measurements were made over the pressure range of 5 to 60 bar. The results are presented as a function of pressure. It has been found that PZ gives significantly higher CO₂ loadings at higher pressures. The influence of pressure on solubility is found to be positive. However, solubility decreases with the increase of temperature and PZ concentration.

Abstract: Cu/TiO₂ photocatalysts with different metal loading were prepared via modified depositionprecipitation method with the intention to reduce the band gap for Orange II degradation and mineralization under visible light radiation. The photocatalysts were characterized using thermal gravimetric analysis, powder X-ray diffraction, diffuse reflectance UV-Visible spectroscopy and field-emission scanning electron microscopy. 10 wt% photocatalysts showed the best performance compared to the bare TiO₂.

Abstract: Photodegradation of 100 ppm diisopropanolamine (DIPA) was studied employing heterogeneous photo-Fenton system using iron modified TiO₂ photocatalyst. A series of Fe/TiO₂ photocatalysts were prepared via hydrolysis-hydrothermal and wet impregnation methods. Photocatalysts prepared using wet impregnation method was found to have similar activity under both UV and visible light. Addition of H₂O₂ during the photodegradation study obviously promoted the COD removal efficiency. When stoichiometric concentration of H₂O₂ was added, as high as 80% of COD was removed within 1.5 h reaction. Further modification is required to increase the photocatalyst performance in photodegradation of DIPA.