摘要
用空气阴极代替锡阴极在Na_2CO_3-Na_2B_4O_7介质中电解合成过硼酸钠.电解结果表明，在阴极电流密度为30～50mA·cm^(-2)时，阴极电流效率为65％～54％．X射线衍射表明结晶产物为NaBO_2·H_2O_2·3H_2O.恒电流计时电位法测定Na_2B_4O_7-H_2O_2和Na_2CO_3-H_2O_2体系电位与时间关系.从iτ^(1/2)～i关系求得过氧化氢与硼酸离子的络合速度常数为7.21×10~3L·s^(-1)·mol^(-1)，过硼酸离子的离解速度常数为2.14×10~2s^(-1).Na_2CO_3-H_2O_2体系的ιτ^(1/2)与i无关，表明过碳酸离子离解速度很大.
Air cathode instead of tin cathode is used to synthesize electrochemically sodium perborate in Na_2CO_3-Na_2B_4O_7 medium.The electrolysis result indicates that the cathode current efficiency is 65%～54%,the corresponding cathode current density being 30～50mA·cm^(-2).X-ray diffraction indicates that the crystal product is NaBO_2·H_2O_2·3H_2O.Constant current chronopo-tentiometry is used to determine the relation between time and potential in Na_2B_4O_7-H_2O_2 medium and in Na_2CO_3-H_2O_2 medium.The rate constant for the complexation of hydrogen peroxide and borate ion and the dissociation rate constant of perborate ion are 7.21×10~3 L·s-l·mol^(-1)and 2.14×10~2s^(-l)respectively,which are calculated from the relati on between iτ^(1/2)and i in Na_2B_4O_7-H_2O_2 medium.The iτ^(1/2)is independent of i in Na_2CO_3-H_2O_2 medium,which indicates that the dissociation rate of percarbonate ion is very fast.
出处
《化工学报》
EI
CAS
CSCD
北大核心
1996年第6期712-717,共6页
CIESC Journal
关键词
过硼酸钠
电解
氧还原
空气阴极
阴极
sodium perborate,electrosynthesis,current efficiency,oxygen reduction,dissociation rate constant
