摘要
水钠锰矿是表生环境中常见的氧化锰矿物之一,影响土壤溶液中硫化物的迁移、转化和归趋。本文考察了酸性水钠锰矿氧化硫化钠溶液的反应过程,采用分光光度法、离子色谱法分析S2-及其氧化产物的浓度和变化趋势,用XRD、SEM表征酸性水钠锰矿粉末反应前后的晶体结构和微观形貌,探讨了温度、pH值、矿物用量对S2-氧化速率的影响。结果表明,S2-的氧化产物主要为单质S,其氧化速率符合准一级动力学规律,且氧化速率随着温度升高、pH值降低和矿物用量增加而增大;酸性水钠锰矿首先被还原生成Mn(OH)2,Mn(OH)2在空气中与O2作用转化成Mn3O4,Mn3O4可进一步转化生成MnOOH。
As one of the common manganese oxide minerals in the supergene environment,birnessite affects the migration,transformation and environmental fate of sulfur in soil.In this study,the oxidation process of sodium sulfide by birnessite was investigated.The kinds and concentrations of oxidation products of sulfides in solution were determined by spectrophotometry and ion chromatography,and the crystal structures and micro-morphologies of solid oxidation products of sulfides were analyzed by XRD and SEM.The influence of temperature,pH value of solution and the amount of added birnessite on the oxidation rate of S2-was studied.It is observed that the main oxidation product of sulfides is elementary substance S,and the S2-oxidation rate follows a pseudo-first-order reaction.Oxidation rate increases with elevating reaction temperature,decreasing pH value of solution and the increase of the amount of added minerals.During the redox process,birnessite is reduced to Mn（OH）2,which can be oxidized into Mn3O4 by O2 in air,and Mn3O4 is further transformed into MnOOH.
出处
《岩石矿物学杂志》
CAS
CSCD
北大核心
2011年第6期1007-1013,共7页
Acta Petrologica et Mineralogica
基金
教育部博士点基金新教师项目(20070504053)
国家自然科学基金(41171375
20807019
40830527)
