Editor-in-Chief: Yoshiyuki Yamashita (Tokyo University of Agriculture and Technology)
Associate Editors-in-Chiefs:
Hiroyuki Honda (Nagoya University)
Takao Tsukada (Tohoku University)

Editors
Tomohiro Akiyama (Hokkaido University)
Georges Belfort (Rensselaer Polytechnic Institute)
Jun Fukai (Kyushu University)
Yutaka Genchi (National Institute of Advanced Industrial Science and Technology (AIST))
Takayuki Hirai (Osaka University)
Masahiko Hirao (The University of Tokyo)
In-Beum Lee (Pohang University of Science and Technology (POSTEC))
Eiji Iritani (Nagoya University)
Hideo Kameyama (Tokyo University of Agriculture and Technology)
Masahiro Kino-oka (Osaka University)
Toshinori Kojima (Seikei University)
Shin Mukai (Hokkaido University)
Akinori Muto (Okayama University)
Nobuyoshi Nakagawa (Gunma University)
Satoru Nishiyama (Kobe University)
Hiroyasu Ogino (Osaka Prefecture University)
Naoto Ohmura (Kobe University)
Mitsuhiro Ohta (Muroran Institute of Technology)
Hiroshi Ooshima (Osaka City University)
Noriaki Sano (Kyoto University)
Manabu Shimada (Hiroshima University)
Masahiro Shishido (Yamagata University)
Shigeki Takishima (Hiroshima University)
Richard Lee Smith, Jr. (Tohoku University)
Yoshifumi Tsuge (Kyushu University)
Da-Ming Wang (National Taiwan University)

Editorial office:
The Society of Chemical Engineers, Japan
Kyoritsu Building, 4-6-19, Kohinata, Bunkyo-ku
Tokyo 112-0006, Japan
journal@scej.org

AIMS AND SCOPE:

Journal of Chemical Engineering of Japan, an official publication of the Society of Chemical Engineers, Japan, is dedicated to providing timely original research results in the broad field of chemical engineering ranging from fundamental principles to practical applications. Subject areas of this journal are listed below. Research works presented in the journal are considered to have significant and lasting value in chemical engineering.

Physical Properties and Physical Chemistry
Transport Phenomena and Fluid Engineering
Particle Engineering
Separation Engineering
Thermal Engineering
Chemical Reaction Engineering
Process Systems Engineering and Safety
Biochemical Food and Medical Engineering
Micro and Nano Systems
Materials Engineering and Interfacial Phenomena
Energy
Environment
Engineering Education

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Experiments have been carried out in a transparent dished bottom stirred tank with a diameter T of 0.48 m and liquid level of 0.6T. The power consumption and mixing performance of a coaxial mixer consisting of a wall-scraping anchor and different inner dispersion impellers (Rushton turbine, 45° pitched blade turbine and CBY) operating in inner impeller-only, co- and counter-rotating modes have been experimentally characterized in viscous Non-Newtonian fluids (2% and 3% w/w CMC solutions) with different rheology behaviors. The results show that, for the co-rotating modes, the power consumption of the anchor could decrease up to 5% of that for the anchor rotating-only mode, whereas for the counter-rotating dispersion modes, it could increase to two times of that for the anchor rotating-only. However, the power consumption of the inner impellers is almost independent of the anchor rotation. We propose new correlations to give better fitted power curves between the generalized Reynolds number and the power number by considering not only the impeller geometry and the characteristic speed, but also the speed ratio. For each coaxial mixer, one reasonable power curve can be generated for different experimental speed ratios and different rotation modes. Impellers in co-rotating mode are more efficient than the inner impeller-only and the counter-rotating modes in the mixing of non-Newtonian fluids. Among the above three dispersion impellers, the power consumption of the CBY-anchor combination is the lowest compared with those for the other two combinations giving the similar mixing performance.

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Bentonites contain a large amount of nano-porous and nano-structured montmorillonite, which is the dominant clay mineral determining the swelling properties of bentonites. In this study, bentonites are categorized into three types, namely swelling (Na-montmorillonite), nonswelling-swelling (Ca,Na-montmorillonite), and nonswelling (Ca-montmorillonite). Soda activation with the optimum parameters also increases the swelling properties of bentonites. The instrumental and experimental analyses for specifying bentonite for each application include pH, Methylene Blue (M.B.) test, Cation Exchange Capacity (C.E.C.) measurements; Swell, M.B., sediment, and colloid indices, dry screen analysis (granulometric analysis), XRD (X-ray diffraction), XRF (X-ray fluorescence). pH results showed higher values for swelling bentonites (group 3) and these values increased after soda activation. The values of C.E.C., M.B. test, and indices are normally higher for group 3 than for group 2 (nonswelling-swelling type). These values were directly related with the amount of clay minerals (montmorillonites) in dry screen analysis. Finally, swelling and non-swelling effects on bentonite particles play an important role in their applications. Swelling bentonites like ES3 are good for applications such as barriers, drilling mud, and plethorapy. Group 2 (nonswelling-swelling) such as S2, G1, and GH1 are good bentonites for use as a filtering agent in juice industries due to being lower voluminous material than that of production with group 3. For pharmaceutical applications, in addition to the swelling index, sediment and colloid indices must be considered.

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Separation of protein by using colloidal gas aphrons (CGAs) is a promising method for removing organic materials from an aqueous solution. In this study, the continuous separation of lysozyme was carried out in a flotation column by using a CGA. The mechanism of adsorption of lysozyme on the CGA and the mass transfer from lysozyme to CGA were investigated. It was found that the adsorption of lysozyme on the CGA followed the Langmuir adsorption isotherm at a lysozyme volumetric flow rate of 2.37 mL/s. In the study of mass transfer, the overall mass transfer coefficient increased with the lysozyme and CGA volumetric flow rates, but decreased with increasing column height. The percentage of protein recovery increased with the lysozyme and CGA volumetric flow rates, column height, and residence time.

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An anodic alumina supported silver catalyst (1.7 Ag/Al₂O₃) was synthesized to investigate the selective catalytic reduction (SCR) of NO under an electrically heating pattern. It was found that less than 1 min was required to heat the catalyst from room temperature to 450°C. Comparing with a common furnace heating pattern, similar de-NO_x activity was achieved. According to the electrically heating tests, the NOx conversion of 1.7 Ag/Al₂O₃ remained above 80% for 15 h at 450°C (F/W = 65000 mL/(g · h)), which proved that it was commendable to apply this type of catalyst to C₃H₆-SCR of NO. Additionally, the promotional effect of hydrogen additive is also discussed under the electrically heating pattern. In the presence of 2000 ppm of hydrogen, the 1.7 Ag/Al₂O₃ reached 80% NO_x conversion within a few seconds at 300°C, while the activity was very low at 300°C without hydrogen; such a high conversion was maintained for 15 h.

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Tar and char are by-products in the supercritical water gasification of biomass, and they reduce the carbon gasification efficiency of the process. The compound 5-hydroxymethylfurfural (5-HMF), a well-known dehydration product of glucose, is suspected to be a chief intermediate in the polymerization pathway that results in the formation of tar and char. In this study, mixtures of glucose and 5-HMF were used as a feedstock; 5-HMF at concentrations of 0.01 to 0.05 M was added to 1.5 wt% (0.083 M) glucose. The reaction occurred under subcritical conditions (i.e., 350°C and 25 MPa). The gas and char formation rates were observed and compared with those in the case of pure glucose. The experimental results show no significant change in the gas and char yields, even though the 5-HMF concentration was increased by a factor of up to 5; this is an unexpected result. An n-th order kinetic model was developed to describe the gasification and polymerization pathways of glucose under subcritical conditions. The main intermediates for gas and char formation remain as TOC (a lumped liquid product).

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The kinetics of the solid-state conversion and crystallization of metal tetrabicycloporphyrins (M-CPs) to metal tetrabenzoporphyrins complexes (M-TBPs) were analyzed by using the Avrami-type equation, and the value of the indices (n) was found to depend on the central atom in M-CP: n = 3 for M = H (TBP), n = 2 for M = Zn, and n = 3 at low temperatures and n = 2 at high temperatures for M = Ni. The heat of crystallization was similar for the M-TBPs, but the activation energy of crystallization varied with the type of central atom. For Ni-TBP and Zn-TBP, metastable phases were first forms, which were then converted into a stable phase, while no such metastable phase was formed in the case of TBP. In addition, the crystallization behavior of TBP was different from that in the thin film state (reported previous study). The crystallization onset temperature varied with the heating rate, although the true temperatures obtained by extrapolating the different heating rates data to zero heating rate were the same. Finally, from the PXRD data, the crystal grains of M-TBPs were found to grow isotropically in the three different directions.

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The objective of our study is to investigate the effect of melt crystallization on inorganic hydrate for purification of crystals including impurity. Melt crystallization is widely applied in the chemical and food industry to purify organic crystals by separating impurities inside the crystals. The target crystals are mainly organic crystals; however, some inorganic crystals are considered for purification by melt crystallization, because of having lower melting point as hydrate crystals. Therefore, we prepared hydrate crystals including impurities and carried out melt crystallization to investigate the purification mechanism on inorganic crystals. Aluminum nitrate nonahydrate was selected as purification target and strontium nitrate was selected as liquid impurity. As solid impurity, we selected barium nitrate. In conclusion, liquid impurity in target crystals was removed by sweating and washing with melt. Moreover, it was considered that the purification mechanism differs depending on the state of the impurity, and melt crystallization is an effective tool for purification the inorganic hydrate crystals.

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The effect of HCl treatment on the porous properties of carbon cryogels synthesized from resorcinol and formaldehyde (RF) is investigated in this work. The treated and untreated carbon cryogels were analyzed with a nitrogen adsorption-desorption apparatus, scanning electron microscope (SEM) and high performance liquid chromatograph (HPLC). The results show that the HCl treatment can enlarge the micropore diameter which is advantageous to electric double layer capacitors, and can broaden the mesopore diameter, which is advantageous to mesoporous carbon supports of catalysts. The micropore volume, mesopore volume and weight loss of the carbon cryogel are not significantly changed by the HCl treatment. Moreover, SEM images and HPLC chromatograms support that the HCl treatment can promote the Ostwald ripening effect for RF carbon cryogels.

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In the industrial crystallization process, it is known that impurities in the mother liquor inhibit the crystal growth or decrease the crystal purity. It is important to investigate the influence of each impurity on the crystal growth and the crystal purity in the presence of admixture impurities assuming a real process. In this study, the influences of impurities on the crystal growth and the crystal purity have been simultaneously evaluated for the growth of crystalline particles in a real process solution in which admixture impurities are present. An operation method is proposed in order to increase the productivity while maintaining a certain crystal purity. The crystal growth rate is increased by masking Ca²⁺, an impurity that inhibits the crystal growth, EDTA to the real industrial process solution. This means that the initial supersaturation σ_i necessary to achieve a certain crystal growth rate can be lowered. Moreover, when the same crystal growth rate is established in two systems, the crystal purity in both systems is found to be very similar. It is found that Ca²⁺ has no influence on the crystal purity, even though Ca²⁺ inhibits the crystal growth rate. This study makes it clear that the driving force of the crystal growth, required for maintaining a certain crystal purity, can be lowered by preventing impurities from inhibiting the crystal growth. Therefore, the proposed operation method can be used in order to improve the productivity while maintaining a certain crystal purity when the crystalline particles are produced in the presence of admixture impurities.

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The pulping industry generates great quantities of wastewaters (WW), where a small amount of black liquor accounts for more than 90% of its entire manufacturing process load in organics. Treatment of the black liquor from pulping manufacture in ThaiNguyen province (Vietnam) by catalytic wet oxidation (CWO) under mild reaction conditions (150–180°C, 15 bar) using solid wastes containing iron oxide as heterogeneous catalysts is communicated herein. These solid wastes have been found to be active in the oxidation of pollutants in the black liquor and show a high application potential in CWO processes for the treatment of this kind of industrial wastewater.

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