Sepiolite, a highly porous mineral, is becoming widely used as an alternative material in areas where sorptive, catalytic and rheological applications are required. High ion exchange capacity and high surface area and more importantly its relatively cheap price make it an attractive adsorbent. In this study, the adsorption of acid red 57 by natural mesoporous sepiolite has been examined in order to measure the ability of this mineral to remove coloured textile dyes from wastewater. For this purpose, a series of batch adsorption tests of acid red 57 from aqueous sepiolite solutions have been systematically investigated as a function of parameters such as pH, ionic strength and temperature. Adsorption equilibrium was reached within 1h. The removal of acid red 57 decreases with pH from 3 to 9 and temperature from 25 to 55 degrees C, whereas it increases with ionic strength from 0 to 0.5 mol L(-1). Adsorption isotherms of acid red on sepiolite were determined and correlated with common isotherm equations such as Langmuir and Freundlich models. It was found that the Langmuir model appears to fit the isotherm data better than the Freundlich model. The physical properties of this adsorbent were consistent with the parameters obtained from the isotherm equations. Approximately, 21.49% weight loss was observed. The surface area value of sepiolite was 342 m2 g(-1) at 105 degrees C, and it increased to 357 m2 g(-1) at 200 degrees C. Further increase in temperature caused channel plugging and crystal structure deformation, as a result the surface area values showed a decrease with temperature. The data obtained from adsorption isotherms at different temperatures have been used to calculate some thermodynamic quantities such as the Gibbs energy, heat and entropy of adsorption. The thermodynamic data indicate that acid red 57 adsorption onto sepiolite is characterized by physical adsorption. The dimensionless separation factor (RL) have shown that sepiolite can be used for removal of acid red 57 from aqueous solutions. The sorption capacity of the sepiolite is comparable to the other available adsorbents, and it is quite cheaper.

中文翻译：

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将酸性红57从水溶液中吸附到海泡石上。

海泡石是一种高度多孔的矿物，在需要吸收，催化和流变应用的领域中，正广泛用作替代材料。高离子交换容量和高表面积，更重要的是其相对便宜的价格使其成为有吸引力的吸附剂。在这项研究中，已经研究了天然介孔海泡石对酸性红57的吸附，以测量该矿物去除废水中有色纺织染料的能力。为此，已经对海泡石水溶液中的酸性红57进行了一系列分批吸附测试，该测试是根据pH，离子强度和温度等参数的函数进行的。1小时内达到吸附平衡。酸性红57的去除随着pH从3降低到9，温度从25到55摄氏度而降低，而随着离子强度从0到0.5 mol L（-1）增加。确定了酸性红在海泡石上的吸附等温线，并与常见的等温线方程式（例如Langmuir和Freundlich模型）相关。发现Langmuir模型似乎比Freundlich模型更适合等温线数据。该吸附剂的物理性质与从等温线方程获得的参数一致。观察到约21.49％的重量减轻。海泡石的表面积值在105摄氏度时为342 m2 g（-1），在200摄氏度时增至357 m2 g（-1）。温度的进一步升高导致通道堵塞和晶体结构变形，结果表面积值显示随温度降低。从不同温度下的吸附等温线获得的数据已用于计算一些热力学量，例如吉布斯能量，热和吸附熵。热力学数据表明，酸红57吸附在海泡石上的特征在于物理吸附。无因次分离系数（RL）表明，海泡石可用于从水溶液中去除酸性红57。海泡石的吸附能力与其他可用的吸附剂相当，并且便宜得多。无因次分离系数（RL）表明，海泡石可用于从水溶液中去除酸性红57。海泡石的吸附能力与其他可用的吸附剂相当，并且便宜得多。无因次分离系数（RL）表明，海泡石可用于从水溶液中去除酸性红57。海泡石的吸附能力与其他可用的吸附剂相当，并且便宜得多。