The natural diatomite was treated with NaOH to obtain alkali-activated diatomite. The materials were systematically characterized by X-ray powder diffraction, X-ray fluorescence, Fourier transform infrared spectroscopic, scanning electron microscopy, and N2 adsorption–desorption. Meanwhile, the potential use of alkali-activated diatomite as adsorbent for the removal of basic fuchsin from aqueous solution was assessed by batch experiment. Results indicated that the structure and textural properties of diatomite were obviously changed via alkali activation, and then affecting its adsorption performance. The adsorption capacity of alkali-activated diatomite for basic fuchsin was higher than that of natural diatomite. In the case of alkali-activated diatomite, its adsorption capacity was increased with increasing the activation temperature, and the diatomite activated at 115°C (alkali-activated diatomite-115) exhibited the maximum adsorption capacity. The pseudo-first-order kinetics and the Sips isotherm model were preferable to describe the adsorption process of basic fuchsin on alkali-activated diatomite-115 and the thermodynamic parameters indicated that the adsorption process was endothermic and spontaneous.

中文翻译：

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碱性品红对碱活化硅藻土的吸附性能

用NaOH处理天然硅藻土，得到碱活化硅藻土。通过X射线粉末衍射、X射线荧光、傅里叶变换红外光谱、扫描电子显微镜和N2吸附-解吸系统地表征了材料。同时，通过批量实验评估了碱活化硅藻土作为吸附剂从水溶液中去除碱性品红的潜在用途。结果表明，碱活化会明显改变硅藻土的结构和质构特性，进而影响其吸附性能。碱活化硅藻土对碱性品红的吸附能力高于天然硅藻土。在碱活化硅藻土的情况下，其吸附能力随着活化温度的升高而增加，115℃活化的硅藻土（碱活化硅藻土-115）表现出最大的吸附能力。拟一级动力学和Sips等温线模型更适合描述碱性品红在碱活化硅藻土-115上的吸附过程，热力学参数表明吸附过程是吸热和自发的。