为研究复杂三元体系中FA(fulvic acid,富里酸)对针铁矿吸附Cr(Ⅵ)的影响,探究FA对重金属Cr(Ⅵ)在环境中迁移转化的作用机理,通过改变FA的添加顺序及添加量,系统研究了FA存在时Cr(Ⅵ)在针铁矿上的吸附行为.结果表明:不添加FA时,离子强度增大促进了针铁矿对Cr(Ⅵ)的吸附;ρ(FA)为50 mg/L时,离子强度增加会抑制针铁矿对Cr(Ⅵ)的吸附.p H为6.98、离子强度为1.0 mol/L时,针铁矿对Cr(Ⅵ)的吸附量比不添加FA时高11.0%.p H为2.98时,添加FA后针铁矿对Cr(Ⅵ)的吸附量最大,比不添加FA时高31.9%.无论是否添加FA,升温均有利于针铁矿对Cr(Ⅵ)吸附,其吸附机理可能是氢键、偶极间力等作用.FA的添加顺序对Cr(Ⅵ)吸附量的影响表现为后添加FA〉先添加FA〉同时添加FA〉对照.研究显示,FA的存在能显著改变针铁矿对Cr(Ⅵ)的吸附行为.
In order to study the interaction process of fulvic acid on the adsorption of Cr( Ⅵ) onto goethite,and explore the fate and transport of Cr( Ⅵ) in the environment,the adsorption behaviors of Cr( Ⅵ) onto goethite and its competitive interaction with fulvicacid were investigated using a series of batch adsorption experiments. The results showed that without addition of FA,the adsorption of Cr( Ⅵ)increased with increasing ionic strength. Meanwhile,the adsorption of Cr( Ⅵ) was inhibited by the addition of FA( 50 mg/L) when ionic strength increased gradually( p H = 6. 98). The sorption capacity was 11% higher than that without addition of FA at the ionic strength of1. 0 mol/L. With the addition of FA,the maximum adsorption capacity of Cr( Ⅵ) onto goethite was 31. 9% higher than that without FA( p H = 2. 98). The increase of temperature was beneficial to the adsorption of Cr( Ⅵ). The possible mechanisms of adsorption were H-bonds and dipolar action force. The influences of different adding order of FA on goethite + chromium( Ⅵ) system was: later addition previous addition simultaneous addition no addition. The results indicated thatthe sorption behaviors of chromium( Ⅵ) on goethite were significantlyaffected by addition of FA.