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วารสารเครือข่ายญี่ปุ่นศึกษา, 12, 2, 33-46

Characteristics of the cadmium adsorption and desorption of a chelating resin CR11 was studied. The Langmuir adsorption model modified for the competitive adsorption of cadmium ion and hydrogen ion was applied to describe the effect of pH on the cadmium adsorption of the chelating resin. The adsorption model well described the experimental data and the maximum adsorption capacity and the adsorption constants of cadmium ion and hydrogen ion were determined. The cadmium desorption efficiency form the chelating resin by an eluent(HCI solution) could also be predicted by the adsorption model. The cadmium removal from the eluent by electrolysis was examined for the reuse of the eluent in the regeneration process of chelating resin. The experimental data well followed the pseudo-first order kinetic model and the kinetic constant was determined. The kinetic constant increased with the increase of electric current up to 0.13 A.

タンパク質を原料とした生物分解性凝集剤の開発を目的として，0.1 M塩酸エタノール溶液でエチルエステル化した卵白アルブミン（EtOA）の凝集剤としての性能を，珪藻土懸濁液をモデル系とした比濁法と沈降天秤法によって，ポリ塩化アルミニウム（PAC）と比較評価した．EtOAを珪藻土に対して1 wt%以上添加することにより高い凝集効果が得られ，凝集体の初期沈降速度は最大0.005 m・s－1であった．凝集体沈降速度はpH 7-10でpHの増加とともに0.003 m・s－1まで低下したが，pH 4-10でPACより高い凝集効果を示した．

水苔由来の腐植物質であるピートモスの重金属吸着剤への利用を目的としてカドミウムと鉛に対する吸着特性について検討した．金属結合サイトである酸性基（カルボキシル基とフェノール性水酸基）の数と解離定数を電位差滴定によって決定した後に，カドミウムおよび鉛吸着実験の結果を酸性基への水素イオンと金属イオンの結合反応に基づく吸着モデルを用いて解析し，ピートモスへの2価金属イオンの吸着がBidentate型であることを明らかにした．ピートモスには約1.5 mmol・g-1の酸性基が存在し，2価金属イオンに対する吸着容量は約0.75 mmol・g-1であった．また，カドミウムおよび鉛イオンの吸着速度過程が擬二次速度式に従うことを示した．

A fundamental study about the selective foam separation of protein mixture was carried out. A solution containing two proteins, Ovalbumin (OA) and Lysozyme (LZ), and an anionic surfactant, Sodium Dodecyle Sulfate (SDS), was adjusted to pH 6.0 which refered to an intermediate state between the isoelectric points of the proteins. The solution was processed by continuous foam separation. The results showed that a proper addition of SDS greatly improved the selective recovery of LZ to OA. The experimental data were well explained by a simple model that most of cationic protein molecules (LZ) are associated with SDS and the adsorption of all the species including LZ-SDS complexes are subjected to Langmuir adsorption isotherm. The results also showed that one of the Langmuir parameters, which means a kind of lyophillic property of adsorbed material, of LZ-SDS complexes was extremely large as compared with that of primary protein.

Adsorption of Water-Soluble Proteins onto Bubbles in Continuous Foam Separation (title on the journal), The enriching mechanism of water-soluble proteins in continuous foam separation was studied. The liquid flow rate and the protein concentration in foam phase were measured at various heights from the interphase between bulk liquid and foam layer, and the intrinsic values at the interface were estimated by the extrapolation method to determine the accurate adsorption density on bubble surface. Ovalbumin (OA) and hemoglobin (HB) were used as the soluble proteins. The solution pHs were varied from 3.5, 4.6 and 6.0 for OA and from 6.0, 6.8 and 8.0 for HB. The experimental isotherms for OA and HB were compared to the Langmuir isotherm, and the two adsorption parameters of the equilibrium constant, K, and the saturated density, γ, at each pH were determined. Both γ values obtained for OA and HB showed maxima at their isoelectric point (i.e.p., pH 4.6 for OA and pH 6.8 for HB). Assuming that OA and HB molecules are spherical in shape and they are adsorbed on bubble surface in a closed packed structure at the saturated condition, the calculated diameters for OA and HB molecules were quite similar to the literature values. The variation in γ for both OA and HB were discussed qualitatively relating to the net charge of protein molecule.