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科学通报  2011 

酸性体系中纳米镍对2,4-二氯苯酚降解性能的研究

, PP. 1308-1316

Keywords: 纳米镍粉,2,4-二氯苯酚,吸附,降解,酸性体系

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Abstract:

纳米金属对有机氯化合物具有较好的脱氯降解效果,但在反应过程中其表面易形成氧化层覆盖,并大量吸附目标反应物导致降解不完全,而酸性体系可避免氧化层的形成.对工业羰基法生产的纳米镍超细粉进行了扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)、能量色散谱仪(EDS)等微观结构观测与表征,并就酸性体系中羰基纳米镍对2,4-二氯苯酚的脱氯降解性能进行了实验研究.结果表明,实验所用纳米镍的颗粒粒径为10~20nm,表面有一较薄的NiO层,其存在将对2,4-二氯苯酚的脱氯降解性能产生较大影响.经酸洗活化处理,并在酸性条件(pH3~4)下反应,可使2,4-二氯苯酚大量降解,并在4h内达到100%的去除率.反应溶液中可检测到2-氯酚、4-氯酚、苯酚等降解产物的出现,以苯酚为主.反应过程中因消耗质子需要定期补加酸量,以维持体系适当的酸度,酸不仅起到调节pH的作用,更是作为一种反应物参与反应,从而极大地促进了脱氯降解反应进程.酸性体系中纳米镍对氯代有机物的脱氯降解反应为二级反应,其反应速率随温度的升高而升高,在3种不同温度(298,306,316K)条件下,其脱氯降解反应速率常数k分别为0.02,0.2和0.3(gLh)-1.

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