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ABSTRACT:Macroreticular chelating resins (RCSNHs) containing amidoxime groups were prepared from chloromethylstyrene--divinylbenzene copolymer beads (RCSs). The RCSs were synthesized by a suspension polymerization in the presence of cyclohexane as a diluent. The introduction of nitrite groups to the RCS could be effectively carried out by treatment with KCN using 18-Crown-6 as a phase transfer catalyst. The products were treated with hydroxylamine in methanol to obtain RCSNH. The influence of macroreticular structure and degree of crosslinking on the adsorption ability of the RCSNH for metal ions was investigated. The RCSNH was prepared from RCS synthesized using 10 mo!% of DVB and 120 vol% of cyclohexane and it showed the highest adsorption ability for Ag+, UO,2 +, and Cu2+. The adsorption ability was greatly affected by macroreticular structure. RCSNHs have high physical stability and resistance against acid solution. Therefore the RCSNHs will be very effective for the recovery and separation of metal ions.KEY WORDS Amidoxime Group/ Chelating Resin/ Recovery of Uranium / Macroreticular / Adsorption of Metal Ion / We prepared and studied many kinds of macroreticular chelating resins containing various ligands and reported that they are more practical than gel-type resins for the removal and recovery of heavy metal ions from industrial waste. 1 -5 We also reported that the chelating resins containing amidoxime groups prepared from acryronitrile-divinylbenzene (DVB) copolymer beads were most effective for recovery of uranium from seawater. 6 -11 Later, chelating adsorbents containing amidoxime groups prepared from polyacryronitrile have been widely investigated by many workers. 12 -17 However, study on adsorbents containing amidoxime groups prepared from other polymer matrices such as polystyrene is rarely reported. 13 · 18 ticular chelating resins (RCSNHs) containing amidoxime groups from chloromethylstyrene (CMS)-DVB copolymer beads (RCSs), and investigated influence of macropore and degree of crosslinking of the resins on the adsorption ability for metal ions. EXPERIMENT AL Preparation of Macroreticular Chelating Resins (RCSNHs)In this article, the macroreticular chelating resins containing amidoxime groups were prepared by the route in Scheme 1. RCSs were synthesized by a suspension polymerization in the presence of cyclohexane as a diluent. Nitrile groups were introduced to the RCS by reaction of RCS (I g) with KCN (0.8 g) in In the present work, we prepared macrore- 120Polym.

A benzoylchitosan was synthesized as a membrane material for separation of benzene/cyclohexane mixtures. When the benzoylchitosan membrane was applied to the permeation and separation of benzene/cyclohexane mixtures in pervaporation, both the permeation rate and benzene concentration in the permeate increased with increasing benzene concentration in the feed, and thus this membrane showed benzene permselectivity. Characteristics of permeation and separation of benzene/cyclohexane mixtures through the benzoylchitosan membrane were analyzed by the solution‐diffusion model. It was found that the benzene permselectivity was dependent on both the sorption selectivity and diffusion selectivity but was significantly governed by the latter. Also a tentative model for the benzene permselectivity is discussed.

SUMMARY: Benzoylcellulose (BzCell) membranes with different degrees of benzoylation were synthesized for the separation of benzene/cyclohexane (Bz/Chx) mixtures. A BzCell membrane with a degree benzoylation of 2 showed high benzene-permselectivity for Bz/Chx mixtures in pervaporation. The permeation rate of the BzCell membrane increases, but the benzene-permselectivity decreases, with increasing benzene concentration in the feed mixture. This increase in the permeation rate is due to an increase in the swelling of the membrane, whereas the benzene-permselectivity was attributed to a decrease in the sorption selectivity. With increasing benzoylation of the BzCells, the permeation rate increases significantly, but the benzene-permselectivity decreases slightly. These results can be explained by the degree of swelling, the density, and the contact angle of the BzCell membranes.