摘要
为了证实添加零价铁对两性高岭土的吸附Cr(VI)的增强作用,并探究外界条件对其吸附效果的影响,将零价铁(ZVI)以1%(质量分数)的比例与0%、10%、20%和40%两性(BS-14,十四烷基二甲基甜菜碱)修饰高岭土混合,形成高岭土(CK)、CK+1%ZVI、10%BS+1%ZVI、20%BS+1%ZVI、40%BS+1%ZVI五组混合样品。批处理法研究不同BS+ZVI样品对Cr(VI)的等温吸附特征,并探讨不同添加比例、温度和离子强度对Cr(VI)吸附的影响。结果表明:BS+ZVI样品对Cr(VI)的吸附为接近线性的优惠吸附,吸附能力表现为40%BS+1%ZVI> 20%BS+1%ZVI> 10%BS+1%ZVI> CK+1%ZVI> CK。在15~40℃范围内,BS+ZVI样品对Cr(VI)的吸附量均随着温度的升高而增大,表现为增温正效应。离子强度在0.01~0.5 mol·L~(-1)范围内,随着离子强度的增大,各BS+ZVI样品对Cr(VI)的吸附量均逐渐降低。40℃和0.01 mol·L~(-1)背景离子条件下,添加1%ZVI对40%BS高岭土吸附Cr(VI)的促进作用最强。
To prove the enhancement role of adding zero-valent iron in Cr(VI) adsorption by amphoteric modified bentonite and explore the effect of external conditions on its adsorption effect,ZVI(Zero-valent iron) is added into 0%,10%,20% and 40% BS-14(Tetradecyl dimethyl betaine) modified kaolins with the mass ratio of 1%,and kaolin(CK),CK+1%ZVI(kaolin with 1%ZVI),10%BS+1%ZVI,20%BS+1%ZVI,40%BS+1%ZVI are prepared as the tested samples.Batch method is used to analyze the adsorption characteristics of Cr(VI) by different BS+ZVI samples,and the effect of different adding proportion,temperature and ionic strength on Cr(VI) adsorption is compared.The results indicate that the adsorption capacity of BS+ZVI samples to Cr(VI) is close to linear preferential adsorption,and the adsorption capacity is 40%BS+1%ZVI > 20%BS+1%ZVI > 10%BS+1%ZVI > CK+1%ZVI > CK;within the scope of 15~40 ℃,the adsorption amount of Cr(VI) on different BS+ZVI samples increases with the rising of temperature,and the adsorption shows positive warming effect;when the ionic strength is within the range of 0.01~0.5 mol/L,the adsorption amount of each BS+ZVI sample to Cr(VI) decreases gradually with increasesing ionic strength;at 40 ℃ and 0.01 mol/L ion background conditions,adding 1% ZVI into 40%BS kaolin could maximally promote the Cr(VI) adsorption.
引文
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