一种硫氧化菌对水泥砂浆的腐蚀机理

Corrosion mechanism of a type of thiooxidant on cement

以天津地区排污管道的腐蚀现象为背景,为了更好地防治地区污水管道的微生物腐蚀,提取本地现有微生物,针对不同的环境对其腐蚀机理进行了研究。试验共设计了4组方案,2种浸泡方式,分5段龄期进行观察。试验使用超景深显微镜和扫描电镜观察了试块的宏观和微观形貌,测量并记录质量和强度的变化规律以及使用XRD进行矿物组分分析,得出以下结论:通入硫化氢气体的试验组试块表面腐蚀速率更快,同龄期下表面粗糙程度更大,其质量与强度损失也更大;半浸组的强度损失大于全浸组,氧气充足较硫化氢气体的作用更为明显;通入硫化氢气体的试验试块内部会产生更多的CaSO_4,C-S-H凝胶结构破坏更为明显;硫氧化菌在没有硫化氢参与时,可以将污水中的含硫物质转化为SO_4^(2-)从而造成硫酸盐腐蚀,在有硫化氢参与时,菌液pH下降,在初期反应生成生物硫酸侵蚀试块表面造成酸腐蚀,达到一定深度后SO_4^(2-)渗入内部同时开始硫酸盐腐蚀,是一种复合作用机理,其腐蚀效果优于单纯的硫酸盐腐蚀。

Based on the corrosion phenomenon of sewage pipes in Tianjin area,the corrosion mechanism of sewage pipes in tianjin area was studied for the purpose of preventing and controlling the microbial corrosion of sewage pipes in tianjin area.The experiment designed 4 groups of plans,2 kinds of soaking methods,and observed by 5 phases of age.Experiments using super depth of field microscope and scanning electron microscope test block of macroscopic and microscopic morphology,measure and record the changing rule of the quality and intensity of mineral composition analysis and the use of XRD,the following conclusion pass into the experimental group of hydrogen sulfide gas block surface corrosion rate faster,more surface roughness under the same age stage,its quality and strength loss is larger.The intensity loss of the half leaching group was greater than that of the whole leaching group.More CaSO4 will be generated inside the experimental block with hydrogen sulfide gas,and the damage of C-S-H gel structure is more obvious.Sulfur oxidizing bacteria in not involved with hydrogen sulfide,sulfur-containing substance in the sewage can be transformed to SO4^2- resulting in sulfate corrosion,the hydrogen sulfide is involved,when bacteria liquid p H decline,the initial reaction generated biological sulfate erosion block surface caused by acid corrosion,after reaching a certain depth of infiltration of SO4^2- internal began to sulfate corrosion at the same time,it is a kind of compound mechanism of the corrosion effect is better than that of pure sulfate corrosion.