摘要
目前,国内外污水处理工艺主要以厌氧-缺氧-好氧(A2/O)处理工艺为主,A2/O工艺是一种典型的除磷脱氮工艺,特点是厌氧、缺氧和好氧三段功能明确,界线分明,可根据进水条件和出水要求,人为地创造和控制三段的时空比例和运转条件,只要碳源充足,便可根据需要达到比较高的脱氮效率。然而,传统A2/O工艺存在以下两个缺点:(1)由于厌氧区居前,回流污泥中的硝酸盐对厌氧区产生不利影响;(2)由于缺氧区位于系统中部,反硝化在碳源分配上居于不利地位,影响了系统的脱氮效果。而当发生偷排、漏排等引起的水质冲击时,A2/O工艺很难在短时间内使水质达到排放要求。电解法处理废水具有效率高、适应性强、无二次污染等特点,在处理有机废水方面优势明显。电化学氧化法是通过电极表面的电催化作用在电极上产生强氧化性物质使有机类化合物氧化降解。由产生强氧化性物质的途径和种类决定,该方法可分为直接和间接电化学氧化两类:(1)直接电化学氧化法通过在阳极表面产生金属过氧化物来实现有机类化合物的氧化降解。电极电解水生成羟基自由基(·OH),·OH与金属氧化物(MOx)结合,形成金属过氧化物。金属过氧化物在有机类化合物降解过程中能够抑制钝化层的形成,促进降解的进行。(2)间接电化学氧化法利用电化学反应过程中产生的氧化剂或短寿命中间物使污染物转化成无害物质。通过电化学氧化可以将H_(2)O生成O_(3)或者·OH,这种方法几乎没有污染,但是O3的生成效率强烈依赖于所用的阳极材料和臭氧反应器,在降解有机污染物时电流效率低,能耗大,因而较少直接应用于实际废水的处理中。二氧化铅(PbO_(2))被认为是一种很有前途的阳极材料,对有机废水的电化学降解具有优异的活性。然而,由于和基底的结合能力较差,PbO_(2)电极稳定性较差,溶解析出铅离子会对
Lead dioxide(PbO_(2))has been regarded as a promising anodic material with superior activity for electrochemical degradation of the organic waste water.However,the PbO_(2)electrode usually suffers from poor stability and the leached lead ions can cause even more serious pollution to the environment.In this work,to enhance the stability of the PbO_(2)electrode,a 10.0μm ofα-PbO_(2)thin film is deposited into the Ti/SnO_(2)-Sb_(2)O_(3)/β-PbO_(2)electrode.Theα-PbO_(2)layer can not only increase the lattice matching between the SnO_(2)-Sb_(2)O_(3)and theβ-PbO_(2)layer but also decrease the internal stress between two different films.With the addition ofα-PbO_(2)thin film,the Ti/SnO_(2)-Sb_(2)O_(3)/α-PbO_(2)/β-PbO_(2)modified electrode shows almost the same electrocatalytic activity as the Ti/SnO_(2)-Sb_(2)O_(3)/β-PbO_(2)electrode,but the stability is greatly improved.In the electrochemical oxidation of toluene diamine(TDA),the modified electrode with theα-PbO_(2)film could stay at a current density of 2.0 A/cm 2 for as long as 750 min in a 4.0 mol/L H 2SO 4 solution,which was 1.56 times longer than that of the Ti/SnO_(2)-Sb_(2)O_(3)/β-PbO_(2)electrode.The degradation pathway of TDA was also studied in detail.This work reports a facil and promising way to stabilize the modified PbO_(2)electrode for electrochemical degradation of organic pollutants.
作者
刘继成
杨仁凯
陈贵生
孙思
韩晓宇
田洁
李晓林
LIU Jicheng;YANG Renkai;CHEN Guisheng;SUN Si;HAN Xiaoyu;TIAN Jie;LI Xiaolin(Chongqing Water Group Co.,Ltd.,Chongqing 400015,China;College of Chemistry and Chemical Engineering,Chongqing University,Chongqing 401331,China;Chongqing Three Gorges Water Service Co.,Ltd.,Chongqing 401122,China;College of Chemistry and Chemical Engineering,Southwest University,Chongqing 400715,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2023年第8期9-14,共6页
Materials Reports
