典型溶质对732苯乙烯磺酸树脂γ-辐解的抑制及其界面动力学

THE INHIBITION OF THE GAMMA RADIOLYSIS OF THE 732 POLYSTYRENE SULFONIC ACID RESIN BY SOME TYPICAL SOLUTES AND THEIR INTERFACE KINETICS

本文研究了X^(-1),Ac^(-1),NO_(3)^(-1),C_(2)H_(5)OH等溶液对苯乙烯磺酸树脂的保护作用,其抑制磺酸基辐射水解的顺序为NO31>C_(2)H_(5)OH>Ac^(-1)>Cl^(-1),Br-1>Ⅰ^(-1)。溶液酸度显著影响卤素离子对磺酸树脂的保护效应,在酸性介质中Ⅰ-几能全部抑制水对树脂的附加辐解,但在中性溶液中,Ⅰ^(-1)只有相当小的抑制作用,且顺序为Br-1,Cl-1>Ⅰ^(-1)。推导了Y辐照下,树脂界面竞争动力学公式。假设激发水分子引起了树脂磺酸基团的辐射水解,求得了抑制剂与H1O*作用相对速率常数之比。k(NO_(3)-+H_(2)O*:kc(2H5 OH+H_(2)O*:k(AC-1+H_(2)O*:k(Cl-1,Br-1+H_(2)O*:k1-1+H_(2)O*=1:0.53:0.46:0.25:0.07.

The protective actions of concentrated solution of X^(-1),Ac-(?),NO_(3)^(-1),and C2H5OH on theγ-radiolysis of the 732 polystyrene sulfonic acid resin have been studied.All of these solutions can inhibit the y radiolysis of the polystyrene sulfonic acid resin.In neutral medium,the abilities of the solutes to inhibit the y radiolysis of the resin are given by the order:NO3-1>C_(2)H_(5)OH>Ac^(-1)>Cl^(-1),Br-1>I^(-1)The protective effect of the halide ion depends strongly on the pH of the solution(see Fig.2).In acid medium,I-1 can effectively inhibit the additional radiolysis of the resin caused by the presence of water,but in the neutral solution,its inhibition effect is rather small.On condition that the excited water molecule can hydrolyze the sulfonic acid group of the resin,the competition kinetic equation on the interface of the resin duringγirradiation can be derived.By plotting the reciprocal of the yield of SO-4 versus the concentration of the inhibitor,linear relationship is obtained(see Fig.3)and the relative rate constants of the reaction between inhibitor and H_(2)O are found as:=1:0.53:0.46:0.25:0.07It shows that the interfacial competitive reaction of the resin not only depends on the property of the inhibitor but is also related to the size of ions and their hydrophilic abilities.Various suggestions of the mechanisms of the inhibition have been discussed.Positive hole(i.e.,H_(2)O+)reaction with scavenger is alsor proposed.