Abstract A monolayer model extended to two energy levels (monolayer model 2) has been developed to fit the adsorption isotherms of acid blue 9 on Spirulina platensis (Sp LEB-52). These isotherms were obtained at different values of pH and different temperatures. The adsorption isotherm modeling was based on a statistical physics approach. The evolutions of stereographic and energetic parameters involved in the model equation were presented in this work. The obtained values of nd1 and nd2 are always higher than unity, indicating that the adsorption of acid blue 9 molecules on Sp LEB-52 is a multimolecular adsorption. The highest adsorption capacity (Qs = 1251.8 mg g−1) is signaled at pH = 4 and T = 298.15 K. Furthermore, we have used the monolayer model 2 as local isotherm to determine the adsorption energy distribution (AED) and the pore size distribution (PSD). The adsorption energy values corresponding to active sites of type 1 and type 2 are, respectively, in the intervals [10.5 − 27.5 kJ mol−1] and [15 − 25 kJ mol−1]. Obtained PSDs indicate that acid blue 9 molecules are adsorbed on macro-pores of Sp LEB-52.

中文翻译：

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基于统计物理方法对钝顶螺旋藻（LEB-52 株）吸附酸性蓝 9 的立体和能量研究

摘要 已经开发了扩展到两个能级的单层模型（单层模型 2）来拟合钝顶​​螺旋藻 (Sp LEB-52) 上酸性蓝 9 的吸附等温线。这些等温线是在不同的 pH 值和不同的温度下获得的。吸附等温线模型基于统计物理方法。在这项工作中介绍了模型方程中涉及的立体和能量参数的演变。得到的nd1和nd2值始终大于1，说明酸性蓝9分子在Sp LEB-52上的吸附是多分子吸附。最高吸附容量（Qs = 1251.8 mg g-1）在 pH = 4 和 T = 298.15 K 时发出信号。此外，我们使用单层模型 2 作为局部等温线来确定吸附能分布 (AED) 和孔径分布 (PSD)。对应于类型 1 和类型 2 活性位点的吸附能值分别在 [10.5 - 27.5 kJ mol-1] 和 [15 - 25 kJ mol-1] 区间内。得到的PSDs表明酸性蓝9分子吸附在Sp LEB-52的大孔上。