Because seashells, which are a waste product in the seafood industry, are not recycled, several studies have investigated effective uses for discarded shells. Herein we report the Cd2＋ ion adsorption performances of ground scallop and pearl shells. The effects of the specific surface area and the crystallite size on the adsorption capacities of Cd2＋ ions were estimated. We found that ground seashells have potential to adsorb Cd2＋ ions.
We measured the removal ratio of Cd2＋ ions using ground shell particles with close to the same specific surface area. The removal ratio of the pearl shells（aragonite form, 9.0 m2/g）and the scallop shells（calcite form, 12.3 m2/g）was 84 ％ and 23 ％, respectively. The pearl shells with low crystallite size exhibited excellent adsorption performance compared to the scallop shells and reagent calcium carbonate. When the aragonite particles were immersed in aqueous solutions including Cd2＋ ions, the ions were easily fixed as cadmium carbonate. On the other hand, the adsorbed amount was positively correlated with the specific surface area of the calcite particles. The adsorbed amount of Cd2＋ ions for aragonite and calcite shell particles depended strongly on the crystallinity and the specific surface area of shells, respectively.
We measured the rest potentials（corrosion potentials）of different metals over 30 days at 50 ℃, 70 ℃, and 90 ℃, while immersed in mother liquors of varying compositions. The metals used for the test pieces were S31600，S31254，S32053，N08354 and N06022 from which evaporators are fabricated. Within those solutions having a composition used in salt production, the effects of the concentration and temperature of the mother liquor on the rest potentials were small and the effects of the concentration of dissolved oxygen（DO）and copper ions in the mother liquor became larger with an increase in the concentration of DO and copper ions. A similar tendency was indicated for the metals used in this study. Thus, to effectively protect metals from corrosion, the concentration of the DO and copper ions in the mother liquor should be controlled. On the other hand, when the DO concentration is greatly reduced, the effects of the copper ions on the rest potentials were small. Thus, it has been suggested that the copper ions accelerate the redox reactions caused by DO.
For dealing with poorly water-soluble drugs having large particles, we studied the effective utilization of sodium chloride（NaCl）. Ibuprofen, which was used as the model drug, was ground with NaCl by means of a planetary ball mill. The average particle size of the pulverized ibuprofen samples was reduced from 39.3 ± 0.7 μm to 1.2 ± 0.2 μm, while the span value was maintained at the low level of 2.7 ± 1.0. The crystal form of ibuprofen remained unchanged after grinding with NaCl, referring to the Powder X-Ray Diffraction（PXRD）results. Moreover, the dissolution rate of ibuprofen was enhanced after ball milling with NaCl, indicating that NaCl could act as an agglomeration inhibitor. This study demonstrated that NaCl offered a potential approach to future studies in pulverizing drugs that are huge in particle size and poorly soluble in water.
The osmotic heat engine（OHE）is a closed-loop pressure-retarded osmosis（PRO）process with a thermally regenerable draw solution（DS）. To obtain the high power density of OHE, high water permeable semi-permeable membranes and DS with high osmotic pressure are necessary. In this study, we investigated the performance of ultrafiltration（UF）membranes as a semi-permeable membrane for an OHE system using polyelectrolyte solution as DS. The osmotic-driven water flux of UF membranes was evaluated using several membranes with different molecular weight cut-off（MWCO）and several polyelectrolytes with different molecular weights（MW）as model DS. High potential of UF membranes as semi-permeable membranes for OHE was shown in the combination with solute of sufficiently larger MW than MWCO of UF membranes.
We investigated the temperature dependence of the membrane properties of poly（vinyl alcohol）（PVA）-based ion-exchange membranes（IEMs）: an anion-exchange membrane（PVA-AEM）and a cation-exchange membrane（PVA-CEM）to measure the water content, transport number and membrane resistance of the IEMs at various temperatures（from 10 to 50 ℃）. The water content of the IEMs was higher than that of commercial IEMs: Neosepta® CMX and AMX, especially at high temperatures. The transport numbers of PVA-CEM and PVA-AEM at 10 ℃ were 0.97 and 0.98, respectively, almost the same as that of the commercial IEMs. The transport numbers of the IEMs as well as the commercial IEMs decreased with increasing temperature; however, PVA-CEM and PVA-AEM still had relative high transport numbers, 0.90 and 0.92, respectively, at 50 ℃. The membrane resistance of PVA-CEM and PVA-AEM were lower than that of CMX and AMX, respectively, at all the measured temperatures.
Reverse electrodialysis（RED）systems are an emerging technology that can generate electric power from seawater and river water using ion exchange membranes. However, recent literature suggested that when a salty solution includes divalent ions in addition to monovalent ions, resulting RED performance dramatically decreases1）. In this study, in order to investigate the degree of performance reduction in the RED due to divalent ions, we have evaluated the membrane potential（OCV）and the membrane resistance（Rm）using a mixed solution of NaCl and MgSO4 with commercial ion exchange membranes（AMX/CMX）. Consequently, about 6 ％ of OCV of both AMX and CMX decreased, and Rm of only CMX increased twice when the molar fraction of MgSO4 was 10 ％. Because these combinational effects will influence the resulting RED performance, the obtained knowledge is useful for practical RED applications using natural feed water.
The objective of this study was to investigate depth heterogeneity of ESPA2 thin-film composite reverse osmosis（RO）membrane in terms of elemental composition and carboxy group distribution. It was found that the O/N ratio is highest at the surface of the polyamide active layer. It was also found that the concentration of deprotonated carboxy group, which was indirectly quantified by measuring ionically associated Ag＋, was highest at the surface of the polyamide active layer and decreased with increased distance from the surface. These results demonstrated that the polyamide active layer of ESPA2 RO membrane has a depth heterogeneous structure.
The size-exclusion chromatography（SEC）column and a novel collagen coated beads column are applied to separation and detection of the adiponectin multimers by high performance liquid chromatography（HPLC）.
Adiponectin, an adipocyte-specific secretory protein, exists in blood as multimers. The multimers are broadly categorized as low, middle and high molecular weight（LMW, MMW and HMW）forms. An enzyme-linked immunosorbent assay（ELISA）system is used widely as an analytical method for the adiponectin multimers. Although the system is used for quantification of total amount of adiponectin molecules in each fraction（LMW, MNW and HMW）, they have no applicability to analysis of the individual multimers. For a better understanding of the biological activity of adiponectin, a method that separates and detects the individual adiponectin multimers is required. In this work, the separation of the multimers was made by HPLC with TSK-gel G4000SW as an SEC column. Moreover, a novel column packed with collagen coated beads was applied to the separation of the multimers. As a result of the use of standard material of adiponectin, the SEC column method detected 4 broad peaks within 30 min under optimum separation conditions. In the case of the use of the collagen column, 5 peaks are detected within 60 min. These results suggest that the developed methods can be used for separation analysis of the individual adiponectin multimers.
This paper examined permselectivity coefficients for Li＋/Co2＋ in electrodialysis through a mono polar cation-exchange membrane, SELEMION CMV, and a monovalent selective cation-exchange membrane, NEOSEPTA CIMS. In the electrodialysis with mono polar membrane, lithium and cobalt ions competitively were transported through the membrane under the wide range of equivalent molar fraction of lithium. The permselectivity coefficient for Li＋/Co2＋ ranged from 0.1 to 0.4. On the other hand, for the monovalent selective cation-exchange membrane, the permeation of cobalt ions to lithium ions greatly decreased, so the permselectivity coefficient was remarkably high, and ranged from 3 to 29 under the conditions studied. These results indicated that a monovalent selective cation-exchange membrane is effective for selective permeation of lithium.