Kaoru Ohe

Degradation of methyl orange using short-wavelength UV irradiation with oxygen microbubbles

A novel wastewater treatment technique using 8 W low-pressure mercury lamps in the presence of uniform-sized microbubbles (diameter = 5.79 microm) was investigated for the decomposition of methyl orange as a model compound in aqueous solution. Photodegradation experiments were conducted with a BLB black light blue lamp (365 nm), a UV-C germicidal lamp (254 nm) and an ozone lamp (185 nm+254 nm) both with and without oxygen microbubbles. The results show that the oxygen microbubbles accelerated the decolorization rate of methyl orange under 185+254 nm irradiation. In contrast, the microbubbles under 365 and 254 nm irradiation were unaffected on the decolorization of methyl orange. It was found that the pseudo-zero order decolorization reaction constant in microbubble system is 2.1 times higher than that in conventional large bubble system. Total organic carbon (TOC) reduction rate of methyl orange was greatly enhanced by oxygen microbubble under 185+254 nm irradiation, however, TOC reduction rate by nitrogen microbubble was much slower than that with 185+254 nm irradiation only. Possible reaction mechanisms for the decolorization and mineralization of methyl orange both with oxygen and nitrogen mirobubbles were proposed in this study.

Cellulose aerogel regenerated from ionic liquid solution for immobilized metal affinity adsorption.

Surface morphology of cellulosic adsorbents is expected to influence the adsorption behavior of biomacromolecules. In the present study, cellulose aerogel regenerated from ionic liquid solution was prepared for use as a polymer support for protein adsorption. Iminodiacetic acid groups were introduced to the aerogel for immobilized metal affinity adsorption of proteins. A Cu(II)-immobilized iminodiacetic acid cellulose aerogel (Cu(II)-IDA-CA), which has a large specific surface area, showed a higher adsorption capacity than Cu(II)-immobilized iminodiacetic acid bacterial cellulose (Cu(II)-IDA-BC) and Cu(II)-immobilized iminodiacetic acid plant cellulose (Cu(II)-IDA-PC). In contrast, the Cu(II)-immobilized cellulosic adsorbents showed similar adsorption capacities for smaller amino acid and peptides. The results show that cellulose aerogels are useful as polymer supports with high protein adsorption capacities.

Adsorption of histidine-containing dipeptides on copper(II) immobilized chelating resin from saline solution.

Adsorption of histidine-containing dipeptides such as carnosine (Car) was investigated using copper(II) immobilized cation exchange resins. Adsorption of Car was enhanced using Cu(II) immobilized resins, on the basis of metal affinity interactions. In particular, iminodiacetic acid chelating resin with immobilized Cu(II) (Cu-IDA) can adsorb Car from saline water. Car was adsorbed on Cu-IDA even in the presence of 1000 mM of NaCl. Adsorption of various amino acids on Cu-IDA was compared under same conditions. Histidine and the histidine-containing dipeptides were selectively adsorbed on Cu-IDA over other amino acids, both in the absence and in the presence of NaCl. Therefore, immobilized metal affinity adsorption is an efficient method for recovering histidine-containing dipeptides from saline water.

Intercalation of 2-aminoethylamino-substituted β-cyclodextrin by γ-zirconium phosphate

The uptake of [6-(2-aminoethylamino)-6-deoxy]-β-cyclodextrin (cden) by γ-zirconium phosphate Zr(HPO4)2·2H2O has been studied at 25 °C. The intercalation behaviour of cden for the γ phosphate is in marked contrast to that observed previously with α-zirconium phosphate Zr(HPO4)2·H2O. The γ phosphate forms initially an intercalated phase in which the cden molecules are arranged as a bilayer of thickness 31.3 A with cavity axes parallel to the phosphate layers. With further increase in the amount of cden added, the thickness of the intercalant layer rapidly decreases to 24.7 A, with an accompanying appreciable decrease in the cden content.

Molecular assembly recognition process. Carbon number selective intercalation of amines by a layered zirconium phosphonate

The reaction of n-alkylamines CnH2n+1NH2(n= 1–10) with a partially phosphated zirconium carboxyethyl-phosphonate shows that only heptylamine (n= 7) is preferentially intercalated to form a bilayer, demonstrating a new class of host–guest process based on molecular assembly recognition.

Synthesis of Glycidyl Methacrylate-Divinylbenzene Microspheres with Aminoalcohol Groups and Their Adsorption Properties for Boron

New adsorbents (AP, AMP, AHMP and MG) were prepared by introducing the aminoalcohol groups such as 3-amino-1, 2-propanediol, 2-amino-2-methyl-1, 3-propanediol, 2-amino-2-hydroxymethyl-1, 3-propandiol and N-methyl-D (-) -glucamine, respectively, to glycidyl methacrylate-divinylbenzene microspheres (GD) in order to investigate the adsorption properties of boron. All experiments were carried out using a batch method. The amount of OH group introduced to microspheres is the following order: MG>AMP>AHMP>AP. The adsorption of boron showed maximums at pH 6-8 for all adsorbents. The adsorption capacity and the adsorption equilibrium constant were determined using the Langmuir equation. Their adsorption capacities for boron are the following order: AHMP>MG>AP>AMP. Although the amount of OH group introduced to AP is less than AMP, the adsorption capacity of AP is higher than AMP. This result suggests that boron prefers the five-membered chelating ring to the six-membered chelating ring. Boron adsorbed on AMP was easily desorbed using 1 mol·dm-3 hydrochloric acid.