Effect of partial delignification of kenaf bast fibers for radiation graft copolymerization

Malaysian kenaf bast fiber was treated by acidic chlorite to be applied for a trunk polymer radiation‐induced graft copolymerization. The delignification conditions such as temperature, reaction time, and sodium chlorite (NaClO₂) loading were optimized from the viewpoints of density, tensile strength, and reactivity of grafting. It was found that delignification condition at 80°C for 6 h with 0.5% NaClO₂ gave 91% of lignin removal from the kenaf bast fibers. In this case, the density, fineness, and tensile strength of the kenaf fiber decreased about 46, 44, and 87%, respectively. Reactivity of grafting was evaluated using 4‐chloromethyl styrene to obtain widely available precursor materials. The partial delignified kenaf with residual lignin less than 2% resulted in degree of grafting of 134%, which is enough for precursor materials. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effects of freezing pretreatment and hygroscopicity of fluidizing particles on drying characteristics of carrots in fluidized bed under reduced pressure

Abstract

A method for low-temperature drying with high drying rate was developed for heat-sensitive foods and agricultural products. A freezing pretreatment was combined with fluidized bed drying under reduced pressure. Cylindrical carrot samples were frozen and then placed without thawing in a fluidized bed of hygroscopic porous silica gel particles that adsorbed water from the sample during the drying process. The effects of the freezing pretreatment and hygroscopicity of fluidizing particles on the drying characteristics of carrots were examined. A higher drying rate was achieved when carrots samples were subjected to freezing pretreatment than without it. At 12?kPa, the volume change was smaller in carrots subjected to freezing pretreatment than in untreated samples. A larger amount of water was absorbed during rehydration by carrots dried at 12?kPa than at 101?kPa within 120?min. The properties of dried carrots were affected not only by freezing pretreatment but also by the pressure applied during the drying process.     

An Additional Insight into the Correlation between the Distribution Ratios and the Aqueous Acidity of the TODGA System

Abstract

Extraction of Eu(III) and Am(III) from HNO₃ into the organic solvents using N,N,N′,N′‐tetraoctyl‐diglycolamide (TODGA) was investigated in order to study the detailed extraction reaction. The chemical species: 1:2 for metal:TODGA complex is present in polar diluents. On the other hand, the metal complexes need three or more TODGA molecules to remain stable in non‐polar diluents. The HNO₃ concentration dependence on the distribution ratio suggests that HNO₃ participates in the metal extraction. Infrared spectra indicate that the carbonyl oxygen coordinates with Eu(III), and luminescence lifetimes suggest that there are no water molecules in the inner coordination sphere of the extracted Eu‐complex.     

Production of FAME from acid oil model using immobilized <Emphasis Type="Italic">Candida antarctica</Emphasis> lipase

Acid oil is a by-product in the neutralization step of vegetable oil refining and is an alternative source of biodiesel fuel. A model substrate of acid oil, which is composed of TAG and FFA, was used in experiments on the conversion to FAME by immobilized Candida antarctica lipase. FFA in the mixture of TAG/FFA were efficiently esterified with methanol (MeOH), but the water generated by the esterification significantly inhibited methanolysis of TAG. We thus attempted to convert a mixture of TAG/FFA to FAME by a two-step process comprising methyl esterification of FFA and methanolysis of TAG by immobilized C. antarctica lipase. The first reaction was conducted at 30°C in a mixture of TAG/FFA (1∶1, wt/wt) and 10 wt% MeOH using 0.5 wt% immobilized lipase, resulting in efficient esterification of FFA. The reaction mixture after 24 h was composed of 49.1 wt% TAG, 1.3 wt% FFA, 49.1 wt% FAME, and negligible amounts of DAG and MAG (<0.5 wt%). The reaction mixture was then dehydrated and used as a substrate for the second reaction, which was conducted at 30°C in a solution of the dehydrated mixture and 5.5 wt% MeOH using 6 wt% immobilized lipase. The activity of the lipase increased gradually when the reaction was repeated by transferring the enzyme to a fresh substrate mixture. The activity reached a maximum after 6 cycles, and the content of FAME achieved was >98.5 wt% after a 24-h reaction. The immobilized lipase was very stable in the first-and second-step reactions and could be used for >100 d without significant loss of activity.     

Active sites of Cu-ZSM-5 for the decomposition of acrylonitrile

The catalytic decomposition of acrylonitrile (AN) over Cu-ZSM-5 prepared with various Cu loadings was investigated. AN conversion, during which the nitrogen atoms in AN were mainly converted to N₂, increased as Cu loading increased. N₂ selectivities as high as 90–95% were attained. X-ray diffraction measurements (XRD) and temperature-programmed reduction by H₂ (H₂-TPR) showed the existence of bulk CuO in Cu-ZSM-5 with a Cu loading of 6.4 wt% and the existence of highly dispersed CuO in Cu-ZSM-5 with a Cu loading of 3.3 wt%. Electron spin resonance measurements revealed that Cu-ZSM-5 contains three forms of isolated Cu²⁺ ions (square-planar, square-pyramidal, and distorted square-pyramidal). The H₂-TPR results suggested that in Cu-ZSM-5 with a Cu loading of 2.9 wt% and below, Cu⁺ existed even after oxidizing pretreatment. The activity of AN decomposition over Cu/SiO₂ suggested that CuO could form N₂, but, independent of the CuO dispersion, nitrogen oxides (NO_x) were formed above 350 °C. Cu⁺ and the square-pyramidal and distorted square-pyramidal forms of Cu²⁺ showed low activity for AN decomposition. Temperature-programmed desorption of NH₃ suggested that N₂ formation from NH₃ proceeded on Cu²⁺, resulting in the formation of Cu⁺. The Cu⁺ ions were oxidized to Cu²⁺ at around 300 °C. Thus, high N₂ selectivity over Cu-ZSM-5 with a wide range of temperature was probably attained by the reaction over the square-planar Cu²⁺, which can be reversibly reduced and oxidized.     

Effect of zeolite in surface discharge plasma on the decomposition of toluene

Toluene was decomposed in a surface discharge plasma reactor packed with various zeolites. The positioning effect of the zeolite bed was also investigated Reactor-B, in which the zeolite bed was located upstream, performed much better than Reactor-A, in which the zeolite bed was located downstream. Furthermore, the decomposition efficiency in Reactor-B increased with the capacity for toluene adsorption on zeolite, while that in Reactor-A did not. The toluene adsorbed in micropores was not decomposed effectively by direct electron impact, but was decomposed by active oxygen species generated in the plasma zone on the zeolite surface. A good correlation was also observed between toluene decomposition and ozone consumption in the downward-type reactor.     

Characterization of alternative plasticizers in poly(vinyl chloride) sheets for blood containers

This study aimed to optimize the ratio of dioctyl 4‐cyclohexene‐1,2‐dicarboxylate (DOTH) and di‐isononyl‐cyclohexane‐1,2‐dicarboxylate (DINCH^®) for use as plasticizers in poly(vinyl chloride) (PVC) sheets. We also evaluated the biological safety of DOTH for its potential to be part of a safe PVC‐based blood container. The suppression of hemolysis in mannitol‐adenine‐phosphate / red cell concentrates (MAP/RCC) with DOTH/(DINCH^®‐PVC) sheets and the elution of plasticizers from the sheets increased with higher DOTH compositions. The properties of the PVC sheet containing DOTH and DINCH^® in the ratio of 25:33 parts against PVC 100 parts as a weight were almost identical to the PVC sheet made of di(2‐ethylhexyl) phthalate. From a subchronic toxicity test, DOTH did not show any adverse effects on all organs, including the testes, epididymis, liver, and kidneys. The no‐observed‐adverse‐effect level was 300 mg/kg body weight/day in a rat. These results suggest that DOTH/DINCH^® (25:33) is a promising candidate for the replacement of di(2‐ethylhexyl) phthalate in blood containers. J. VINYL ADDIT. TECHNOL., 22:520–528, 2016. © 2015 Society of Plastics Engineers     

Characterization of anisotropic gas permeability and thermomechanical properties of highly textured porous alumina

Porous alumina with a highly textured microstructure was fabricated by pulse electric current sintering (PECS) using alumina platelets. Highly oriented porous alumina with a porosity of 3%–50% was obtained by a pressure-controlled method of PECS. The properties of the highly textured porous alumina were measured in two directions. The nitrogen gas permeance and thermal conductivity at room temperature were higher in the direction along the platelet length due to the higher continuity of pores and the connectivity of alumina platelets, respectively. The anisotropy of the thermal conductivity at room temperature was investigated and explained by the effect of grain size of platelets as well as morphology and orientation of pores. The bending strength was higher with the loading direction along the platelet thickness. The thermal shock strength was clearly different in the two directions. The difference in the thermal shock strength was investigated by the measurement of properties and thermal stress analysis.     

Separation of Ru(III), Rh(III) and Pd(II) from nitric acid solutions using ion-exchange resins bearing carboxylic betaine

To understand the adsorption properties of a styrene–divinylbenzene copolymer functionalized with N,N,N-trimethylglycine, AMP03, the adsorption behaviours for platinoid ions (Ru(III), Rh(III) and Pd(II)) were examined. Furthermore, we performed adsorption experiments using sample solutions by adding triethylamine, thiourea and N,N,N-trimethylglycine. Based on the adsorption data obtained in this study, we performed chromatographic experiments. The results indicated that all platinoid ions in the feed solution completely adsorbed on AMP03, and almost 80% of the adsorbed platinoid ions were recovered. These results show that AMP03 has the potential to recover Ru(III), Rh(III) and Pd(II) from high-level liquid waste.