Hiroshi Masamoto

Solvent effects on the electronic state of monolignol radicals as predicted by molecular orbital calculations

The spin and charge densities in three monolignol radicals were computed using the UB3LYP/6-31G* method of molecular orbital calculation. As well, the effects of solvents were simulated by using an SCI-PCM model. It was confirmed that an unpaired electron was localized at C1, C3, C5, C8, and O4 for all monolignol radicals. In solvents, the spin density decreased at O4 with increasing solvent polarity, but increased at C8. The atomic charges at all reactive atoms had a negative value and were obviously strengthened at O4 with increasing solvent polarity. These tendencies support the experimental results for radical coupling reactions of monolignols in various solvents; that is, that 8-O4′ linkages are produced much more often than 8-8′ linkages in nonpolar solvents.

Improvement of oxidation stability of biodiesel by an antioxidant component contained in spent coffee grounds

ABSTRACT In this work, biodiesel was produced from spent coffee grounds (SCG) oil extracted using n-hexane as a non-polar solvent, and acetone and 1-butanol as polar solvents, in order to simultaneously obtain SCG oil and antioxidant component. Moreover, oxidation stability and antioxidant capacity of SCG oil and their biodiesel production process were evaluated using the Rancimat method and oxygen radical absorbance capacity (ORAC) method, respectively. ORAC values of SCG oil from polar solvents and a non-polar solvent were 97–98 and 93–386 μmol-TE/g, respectively. Antioxidant activities of SCG oils from polar solvents were higher than those of SCG oil from non-polar solvent. However, these ORAC values were decreased by one third on raw oils during biodiesel production model experimental. These characteristics were utilized to develop an improved method of producing waste rapeseed biodiesel: (1) blending the SCG oil with rapeseed oil; (2) soaking powdered SCG in the reaction mixture during biodiesel production; and (3) adding active components extracted using methanol. In method (1), oxidation stability was improved such that 10 wt% of polar solvent extracted SCG oils increased the stability from 1 to 3 h. Also, oxidation stabilities in methods (2) and (3) were improved by soaking 40 wt% SCG and adding 1 wt% SCG extract, respectively.

Thermal Behavior of Used Alkaline Primary Button Batteries Disposed as General Waste

The thermal behavior of new (1.5 V) and used (0 V) primary LR1130 alkaline button batteries was investigated by thermogravimetric differential thermal analysis (TG/DTA). The anode (MnO2) and cathode (Zn) from the batteries were mixed with paper or plastic (1:1). Cellulose and polyethylene were used to represent paper and plastic, respectively. The thermal behavior of MnO2, Zn and the separator from both new and used batteries was comparable by TG/DTA using. There was no exo- or endothermic decomposition of Zn and minor exothermic decomposition of MnO2 from new and used batteries. MnO2 and Zn were markedly affected by the thermal decomposition of cellulose. However, cellulose mixed with MnO2 was more of a thermal hazard than when mixed with Zn. Moreover, MnO2 and Zn from both new and used batteries were also affected considerably by the thermal behavior of polyethylene. Therefore, the accidental disposal of used alkaline button batteries shows high potential to lead to an accident.

Reduction of the Cloud Point of Biodiesel by Combination of Various Factors

Optimization to reduce the cloud point of biodiesel fuel (BDF) was investigated by considering the combination of different kinds of alcohols for transesterification, catalyst type, and blending with castor BDF. Rapeseed oil (R), spent coffee oil (S), and jatropha oil (J) were used as raw materials. The cloud point of BDFs prepared with 1-butanol was found to be lower than that of those using methanol. H2SO4 was a more effective catalyst to reduce cloud point than NaOH. As for blending with castor BDF, the cloud point was decreased from −7 to −7.5 °C for a 25 wt% blend of castor BDF with R-BDF, from 10.2 to 8.0 ° C with S-BDF, and from 8.2 to 2.8 ° C with J-BDF with permissible increases of kinetic viscosities. From the above results, the optimized conditions of 1-butanol, H2SO4 and 25 wt% castor BDF were determined. Under these conditions, the cloud points were −7.5, 2.8 and −3.5 °C for R., S. and J. BDFs, respectively. This paper that the blend ratio of castor BDF was at 25 wt% or less, it was possible to suppress the increase in kinetic viscosity.

Treatment of Wastewater by Fluidized-Bed Bioreactor with Self-Coagulated Activated Sludge Granules Containing Vegetable Carrier.

植物性担体を包括造粒した活性汚泥粒子による流動層を用いて実廃水の長期連続処理運転を行った.粒子は特別に熟成された植物性担体を用いることにより約1日で造粒され, 運転開始にあたって予備操作を必要としなかった.また, この担体包括粒子は操作条件の急変などにより一たん破壊されても, 適当な操作により速やかに正常化することが確かめられた.処理水質は, リアクター出口での溶存酸素濃度が0～0.5mg・l-1と低い場合でも良好でありBOD容積負荷2.9kg-BOD・m-3・d-1までは処理水BOD5を20mg・l-1に維持できた.さらに, 本法は標準活性汚泥法や自己造粒粒子を用いるMRB法, AUSB法などに比較して, BOD-容積負荷, BOD-SS負荷および酸素消費などの点で優れた特性をもつことが判明した.

Activate sludge treatment of slacked lime pretreated formalin containing hospital waste.

石灰処理して無毒化した病院ホルマリン廃液のCOD値を活性汚泥法で低下させる実験を行った. (1) 円筒型ガラスビン(容量2l)中で試料1容と活性汚泥2容との混合液(COD 100～400mg/l, MLSS 3000～8400mg/l)を曝気すると,混合液のCOD値は1夜で60mg/l以下に減少した. (2) この曝気処理を1日, 1回, 3分の1回分方式で繰り返すと,経日的に活性汚泥は試料に馴致され, COD値の減少速度はしだいに速くなり,数日でほぼ最高値に達した. (3) 活性汚泥法による既設排水処理場(曝気槽170m3×2)に試料(COD 62,000 mg/l)201lを投入速度約3l/分で投入した場合,曝気槽出口のCOD値は1時間後に最高33mg/lに達したが,以後しだいに減少し,通常の運転時(雑排水のみの対照)と同じ20mg/l以下になった.放流水は無色透明で,そのCOD値は常に20mg/l以下であった. (4) 1日量108lの試料を隔日的に3回連続処理した場合も, COD値, SVI,透視度等は試料を投入しない対照とほとんど同じ良い値を示した. 以上のことから,病院ホルマリン廃液の石灰処理と活性汚泥法を組み合せた2段階式の浄化処理法の有効性が示された.