联合法赤泥的特性及其对水溶液中Pb(Ⅱ)的去除  

Characteristics of red mud in combined process and its performance on Pb(Ⅱ)removal in aqueous solution

作　　者：王笑 刘元元[1] 汪军[2] WANG Xiao;LIU Yuanyuan;WANG Jun(Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment,Ministry of Education,Chongqing University,Chongqing 400045,China;Chongqing Academy of Environmental Science,Chongqing 401147,China)

机构地区：[1]重庆大学,三峡库区生态环境教育部重点实验室,重庆400045 [2]重庆市环境科学研究院,重庆401147

出　　处：《环境工程学报》2020年第2期515-522,共8页Chinese Journal of Environmental Engineering

摘　　要：赤泥作为氧化铝冶炼过程中排出的一般工业固废,具有数量大、碱性强、粒径小、孔隙结构丰富等特征。采用XRF、XRD、SEM/EDX等分析手段,研究了赤泥的化学组成、矿物结构、粒度、比表面积、表面形貌、酸中和能力等特性。通过批实验观测了赤泥对水溶液中Pb(Ⅱ)的去除效果,并对Pb(Ⅱ)初始浓度、pH等影响因子对去除效果的影响展开了分析。结果表明,赤泥的主要化学成分为CaO、SiO2、Al2O3和Fe2O3,平均比表面积为43.8 m^2·g^-1;赤泥有很强的酸中和能力,对硝酸的中和能力约为1.875 mol·kg^-1。初始pH=4,且过程中不控制pH时,反应在10 min之内达到平衡,去除率为98%~100%,赤泥对Pb(Ⅱ)的去除能力可达到25.9 mg·g^-1。当pH=4时,赤泥对水溶液中Pb(Ⅱ)的去除反应在90~120 min时达到平衡,去除率为10%~45%,当初始浓度为1~100 mg·L^-1时,Pb(Ⅱ)初始浓度越高,Pb(Ⅱ)去除能力越强,去除率越低。当pH为7和10时,Pb(Ⅱ)去除率分别为92%和98%,残留Pb(Ⅱ)浓度小于污水综合排放标准中第一类污染物最高允许排放浓度1.0 mg·L^-1。通过分析可知,赤泥对Pb(Ⅱ)的去除符合拟二级动力学模型,吸附机理主要为化学吸附。As a general industrial solid waste discharged from the smelting process of alumina, bauxite residue(red mud) is characterized as large quantity, strong alkalinity, small particle size and rich pore structure.XRF,XRD, SEM/EDX and other analytical methods were used to study its chemical composition, mineral structure,particle size, specific surface area, surface morphology and acid neutralization ability. The batch experiments were conducted to study the Pb(Ⅱ) removal effect in aqueous solution by red mud, and the influences of Pb(Ⅱ)initial concentration and pH on the removal effect were analyzed. The results showed that the main chemical components of red mud were CaO, SiO2, Al2O3 and Fe2O3, and its average specific surface area was 43.8 m2·g^-1.Red mud had strong acid neutralization ability which was 1.875 mol·kg^-1 towards nitric acid. At the initial pH=4, the Pb(Ⅱ) absorption reaction reached equilibrium within 10 min when the pH was not controlled during the process, the corresponding Pb(Ⅱ) removal rate was 98%~100% with Pb(Ⅱ) removal ability of 25.9 mg·g^-1.At pH=4, the Pb(Ⅱ) removal reaction in aqueous solution reached equilibrium after 90~120 min, and the removal rate was 10%~45%. Among the Pb(Ⅱ) initial concentrations of 1~100 mg·L^-1, the higher the initial Pb(Ⅱ) concentration, the larger removal amount and the lower removal rate of Pb(Ⅱ). When pH values were 7 and 10, the Pb(Ⅱ) removal rates were 92% and 98%, respectively, and the residual Pb(Ⅱ) concentration was less than the maximum permissible discharge concentration of 1.0 mg·L^-1 for pollutant type I in comprehensive discharge standard. The Pb(Ⅱ) removal by red mud accorded with the quasi-secondary kinetic model, and the removal process was dominated by the chemisorption mechanism.

关 键 词：赤泥 碱性 重金属 铅离子 综合利用 

分 类 号：X705[环境科学与工程—环境工程]