高钙煤气化渣和燃烧渣对模拟废水中Pb^(2+) 的脱除作用对比研究  

Comparative Study on Removal of Pb^(2+)from Simulated Wastewater by High Calcium Coal Gasification Slag and Coal Combustion Slag

作　　者：吕飞勇 初茉[1] 袁旖璠 孙星博 刘彦妤 王浩阳 LYU Feiyong;CHU Mo;YUAN Yifan;SUN Xingbo;LIU Yanyu;WANG Haoyang(School of Chemical and Environmental Engineering,China University of Mining and Technology(Beijing),100083 Beijing,China)

机构地区：[1]中国矿业大学(北京)化学与环境工程学院,北京100083

出　　处：《煤炭转化》2022年第6期46-53,共8页Coal Conversion

基　　金：国家重点研发项目(2019YFC1904304);国家自然科学基金资助项目(51974323).

摘　　要：以高钙煤气化渣和煤燃烧渣为原料开展对Pb^(2+)脱除的对比实验研究,考察了接触时间(0 h~72 h)、灰渣投加量(0.05 g~0.20 g)、Pb^(2+)溶液初始pH值(2.5~6.0)对Pb^(2+)脱除的影响,分析了钙元素在Pb^(2+)脱除过程中的作用,并对比分析了两类灰渣的脱除机制。结果表明:Pb^(2+)初始质量浓度为100 mg/L、模拟废水体积为50 mL、接触时间为24 h、灰渣投加量为0.20 g、Pb^(2+)溶液初始pH值为5时,灰渣对Pb^(2+)脱除效果最优,燃煤渣和气化渣对Pb^(2+)的脱除率分别高达94.5%和99.5%;燃煤渣脱除Pb^(2+)的过程包括灰渣水解产OH-,析出Pb(OH)_(2)晶粒,吸收空气中CO_(2)转变为碱式碳酸铅[Pb_(3)(CO_(3))_(2)(OH)_(2)]并最终絮凝沉淀三个阶段,属于化学沉淀作用;气化渣脱除Pb^(2+)的过程除了化学沉淀作用外,灰渣中多孔残碳颗粒的物理吸附也起到了促进作用。高钙灰渣应用于重金属污染废水的治理是实现其资源化、增值化利用的有效途径之一。High calcium coal gasification slags and coal combustion slags were used as raw materials to carry out an experimental study on the removal of Pb^(2+)in simulated wastewater.The influence of contact time(0 h-72 h),dosage of sags(0.05 g-0.20 g),initial pH value of Pb^(2+)solution(2.5-6.0)on the removal capacity of Pb^(2+)was investigated.The effect of calcium element on the removal process was analyzed,and the removal mechanisms of two kinds of slags were compared.The results show that under the condition of initial concentration of Pb^(2+)is 100 mg/L,volume of wastewater is 50 mL,contact time is 24 h,dosage of slags is 0.20 g and initial pH value of Pb^(2+)solution is 5,the removal efficiency of Pb^(2+)by slag is the highest.The removal rates of Pb^(2+)by coal combustion slag and gasification slag are up to 94.5%and 99.5%.The process of Pb^(2+)removal from coal combustion slags includes three stages:hydrolysis of slag to produce OH-,precipitation of Pb(OH)_(2) grains,absorption of CO_(2) in air to transform into basic lead carbonate[Pb_(3)(CO_(3))_(2)(OH)_(2)]and finally flocculation and precipitation,which belongs to chemical precipitation.In addition to chemical precipitation,physical adsorption of porous residual carbon particles in slags also plays an important role in removing Pb^(2+).The application of high calcium slags in the treatment of heavy metal polluted wastewater is expected to be an effective way for its value-added utilization.

关 键 词：高钙 煤气化渣 燃煤渣 Pb^(2+) 脱除作用 

分 类 号：TQ536.4[化学工程—煤化学工程] X703[环境科学与工程—环境工程]