改性锰矿的除砷性能研究

Study on the adsorption performance of modified manganese ore for the removal of arsenic

利用共沉淀-煅烧法对天然锰矿进行改性,研究了铁锰摩尔比(Fe/Mn)、pH、温度、共存离子对改性锰矿除砷效果的影响。采用X射线荧光光谱(XRF)、傅立叶红外光谱(FTIR)、扫描电镜(SEM)对其进行表征,探究改性锰矿除砷机理。结果表明:(1)Fe/Mn为12∶1时对As(Ⅲ)有最大去除率(88.63%),4∶1时对As(Ⅴ)有最大去除率(84.25%)。(2)弱酸性、中性及弱碱性的溶液反应环境有助于改性锰矿对砷的吸附。(3)Ca2+促进砷吸附,HCO3-抑制砷吸附。(4)改性锰矿对砷的吸附过程符合Langmuir吸附等温方程和二级动力学方程。(5)可利用Na2CO3溶液对改性锰矿进行再生解吸,再生5次后的改性锰矿对As(Ⅲ)和As(Ⅴ)的去除率分别为81.27%、75.99%。

Natural manganese ore was modified by coprecipitation-calcination method,the effects of ironmanganese molar ratio(Fe/Mn),pH,temperature and coexisting ions on the removal of arsenic by modified manganese ore were discussed.The arsenic removal mechanism of modified manganese ore was investigated by the characterization of X-ray fluorescence(XRF),Fourier transform infrared spectroscopy(FTIR)and scanning electron microscopy(SEM).The results showed that:(1)the removal rates of As(Ⅲ)(88.63%)and As(Ⅴ)(84.25%)were maximum when Fe/Mn were 12∶1 and 4∶1,respectively.(2)The reaction environment of weakly acidic,neutral and weakly alkaline solutions contributed to the adsorption of arsenic by modified manganese ore.(3)Ca2+ promoted the adsorption of arsenic while HCO3- had a negative effect.(4)The adsorption of arsenic by modified manganese ore was conformed to the Langmuir adsorption isotherm equation and secondary kinetic equation.(5)Na2CO3 solution could be used for regeneration and desorption of modified manganese ore.After five times of regeneration,the removal rates of As(Ⅲ)and As(Ⅴ)were 81.27% and 75.99%,respectively.