【摘要】 在实验室模拟了纸浆的工业次氯酸盐单段漂白过程,对该过程中二英(polychlorinated dibenzo-pdioxins and polychlorinated dibenzofurans,PCDD/Fs)的生成情况进行了研究,结果表明,次氯酸盐漂白过程中有少量PCDD/Fs生成,且产物以TCDF为主.在此基础上,研究了不同次氯酸钠用量和不同初始pH对PCDD/Fs的影响.结果显示,在较高次氯酸盐用量条件下PCDD/Fs浓度降低,说明高次氯酸钠用量对PCDD/Fs的生成有一定的抑制,或者对PCDD/Fs有降解作用;pH值对PCDD/Fs生成的影响主要表现在PCDD上,在中性和弱酸性条件下,高氯代PCDD的量有所增加,而TCDD减少.对草浆甲苯提取物和提取后纸浆次氯酸盐漂白产物对比发现,次氯酸盐漂白过程中PCDD/Fs的生成主要来源于可提取部分.因此,在工业次氯酸盐漂白过程中可以通过增加水洗次数的方法来减少漂白过程总有机氯化物的生成.更多还原

【Abstract】 Hypochlorite bleaching experiments in a laboratory scale were performed to investigate the change of PCDD / Fs during the hypochlorite bleaching process. The results indicated that small amount of PCDD / Fs were produced during the hypochlorite bleaching process,and TCDF was the dominant congener. Based on this,the effect of initial pH and hypochlorite dosage was investigated. high hypochlorite dosage lead to lower PCDD / Fs production, which indicated that either the formation of PCDD / Fs was inhibited,or PCDD / Fs were degraded at high hypochlorite dosage. The pH effect was mainly on the formation of PCDD. Under neutral and weak acid conditions,the content of higher chlorinated PCDD increased,but TCDD content decreased. Moreover,by comparing the toluene-extracted pulp and hypochlorite bleached pulp,it was found that the majority of PCDD / Fs were generated during toluene extraction. Therefore,increasing the washing times may be an effective way to reduce the formation of organic chlorine compounds during the industrial hypochlorite bleaching process.更多还原