摘要:
为了验证各种典型吸附模型在非线性拟合和线性拟合的条件下,拟合结果是否相同这一问题,文章以沙粒对氨氮的吸附试验为例,对Langmuir和Freundlish吸附等温线模型以及准一级和准二级吸附动力学模型和附热力学Van't Hoff模型进行了相同试验数据条件下的非线性拟合和线性拟合。结果表明,两种吸附等温线模型和准一级动力学模型的线性拟合相关系数小于对应的非线性拟合相关系数,并且两种拟合所得参数的差距也较大;但是,在准二级吸附动力学模型和Van't Hoff模型中,情况又有所不同,表现出来线性拟合的相关系数大于等于非线性拟合的相关系数,并且两种拟合所得参数的相对误差小于1%,因此,可将其作为判定线性拟合结果是否合理的一个参考依据。综上所述,吸附模型的拟合应尽量采用非线性拟合,如若采用线性拟合,则有可能会带来较大的误差,从而影响吸附模型的精度。
关键词:
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吸附模型
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非线性拟合
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线性拟合
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砂粒
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氨氮
Abstract:
In order to verify whether the fitting results were same by nonlinear fitting and linear fitting about various typical adsorption models, the paper taken the experiment of sand adsorbing ammonia nitrogen. The Langmuir and Freundlish adsorption isotherm models, pseudo-first-order and pseudo-second-order adsorption kinetics models and Van't Hoff model of adsorption thermodynamics were fitted by nonlinear and linear fitting with the same experimental data.The results showed that the correlation coefficients of nonlinear fitting for Langmuir model, Freundlish model and pseudo-first-order kinetics model were greater than corresponding linear fitting and the parameters obtained by linear fitting were very different with the nonlinear fitting.But, the situation of fitting results for pseudo-second-order adsorption kinetics model and Van't Hoff model was different.The correlation coefficient of linear fitting was greater than or equal to nonlinear fitting correlation coefficient, and the relative errors of parameters obtained by nonlinear fitting and linear fitting were less than one percent.So it could be considered as a reference for adsorption models to determine whether linear fitting result is suitable.In summary, the nonlinear fitting is proposed to adsorption models processing.If adsorption models were fitted by linear fitting, it is likely to bring about a bigger error and influence the precision of the models.
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