有机改性硅藻土对甲基橙、酸性绿两种阴离子的吸附实验研究

An experimental study on the adsorption of methyl orange and acid green ions on organic modified diatomite

阳离子表面活性剂十六烷基三甲基溴化铵可以有效对天然硅藻土进行有机改性,获得有机改性硅藻土。有机改性硅藻土对富含甲基橙、酸性绿溶液的吸附实验研究结果表明,在相同条件下,改性硅藻土对甲基橙的吸附效果比较好,对酸性绿的吸附效果不是很理想,但也远远高于硅藻土原土对这两种阴离子的吸附效果。在室温条件下,当甲基橙溶液的浓度为20mg/L时,改性硅藻土投加量为0.2g、pH值为4、吸附时间为80min,改性硅藻土对其的吸附效果较好;在室温条件下,当染料酸性绿溶液的浓度为20mg/L时,改性硅藻土投加量为0.15g、pH值为4、吸附时间为80min,改性硅藻土对其的吸附效果较好;两种阴离子的吸附过程均符合Freundlich模型。基于n值对比分析,改性硅藻土对甲基橙的吸附属于优惠吸附,而对酸性绿的吸附属于非优惠吸附。

Organic modified diatomite（ORD）is successfully obtained from theorganic modification process of natural diatomite byhexadecy ltrimethyl ammonium bromide（CTAB）which works asa kind of cationic surfactant.The experimental results of ORD＇s absorption capacity of methyl orange and acid green solution showed that：under the same condition,the effect of ORD＇sadsorption of acid green was not as ideal as its absorption effect of methyl orange,yet ORD＇s absorption capacity of these two negative ions was still much higher than the natural diatomite＇s.At the room temperature,the highest adsorption capacity of methyl orange was obtainedwhilethe concentration of methyl orange solutionwas 20mg/L and 0.2g of modified diatomite was added at pH=4within 80min;at the room temperature,the relatively higher adsorption capacity of acid green was obtainedwhilethe concentration of acid green solutionwas 20mg/L and 0.15 g of modified diatomite was added at pH=4within 80 min.Both of the absorption process of these two negative ions were in accordance with Freundlichisothermal adsorptionmodel.By comparing the value of n,the authors found that ORD＇s adsorption of methyl orange was favorable adsorption,while that of acid green was unfavorable absorption.