【摘要】 采用室内实验方法,研究了农药的初始浓度以及水中存在的腐植酸、盐类物质对双草醚钠盐水解作用的影响。结果表明,相同介质中,不同初始浓度双草醚钠盐的水解速率有差异,在实验浓度范围内,随着双草醚钠盐初始浓度的增加水解越明显。在pH值为3时,棕色和白色容量瓶中1 mg.L-1的半衰期为693 h;10 mg.L-1时分别为60.3和83.5 h;20 mg.L-1时则分别为55.5和74.5h。还可以看出,双草醚钠盐在水环境中的水解速率除受农药初始浓度的制约外,还受到反应容器的材料性质的影响。腐植酸可以加快双草醚钠盐的水解反应速率,并且腐植酸浓度越大,越能促进水解。腐植酸浓度从0到1 000 mg.L-1,双草醚钠盐的水解速率增加了110%。NaCl浓度由0增至1 mol.L-1,双草醚钠盐的水解速率常数K值下降了61%。可见水体中溶解盐的存在在一定的程度上抑制了双草醚钠盐的水解,而且随其浓度越大,水解速率越小。研究结果对受农药污染水体的治理有一定的指导意义。更多还原

【Abstract】 Bispyribac-sodium,sodium 2,6-bis[(4,6-dimethoxy-2-pyrimidinyl)oxy]benzoate,is a selective,systemic post-emergence herbicide,absorbed by foliage and roots.It is not only used to control grasses,sedges and broad-leaved weeds,especially Echinochloa spp.,in direct-seeded rice,at rates of 15~45 g·hm-2,and also used to stunt growth of weeds in non-crop situations.The influences of the initial concentration,humus and brine on hydrolysis of bispyribac-sodium were studied.The hydrolysis of bispyribac-sodium was obtained at 298 K and pH 3.The result showed that humus could promote the hydrolysis,and with the humus concentration increasing from 0 to 1 000 mg·L-1,the hydrolysis rate constant K values of bispyribac-sodium increased 110%.Brine could inhibit the hydrolysis of bispyribac-sodium,with the salinity concentration increasing from 0 to 1 mol·L-1,the hydrolysis rate constant K values of bispyribac-sodium decreased 61% approximately.In addition,the initial concentration of bispyribac-sodium also influenced its degradation rate,the lower the initial concentration,the slower the degradation rate of bispyribac-sodium.The herbicide bispyribac-sodium was not stable in acid solutions.These results provided the theoretical basis for environmental effects of bispyribac-sodium更多还原