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首页> 外文期刊>International Journal of Environmental Science and Technology >Empirical and mechanistic evaluation of sodium exchange isotherms on natural mineral and organic adsorbents and organically functionalized nanoparticles
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Empirical and mechanistic evaluation of sodium exchange isotherms on natural mineral and organic adsorbents and organically functionalized nanoparticles

机译：对天然矿物质和有机吸附剂以及有机功能化的纳米颗粒进行钠交换等温线的经验和机理评估

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This study was conducted to evaluate the efficiency of low-cost adsorbents including bentonite, kaolinite and zeolite saturated with calcium and potassium, potato and wheat residues, and three metal oxide nanoparticles functionalized with an acidic extract of potato residues in improving the quality of sodic waters. The optimization of factors such as pH, contact time, and adsorbent dosage was investigated using a solution containing sodium, calcium, magnesium, and potassium. The optimal pH and contact time were 7.0 and 24 h, respectively. The optimal dosage for using functionalized nanoparticles was 0.1 g and for using other adsorbents was 1.0 g. The sodium exchange isotherms were conducted in binary sodium-calcium and sodium-potassium and quaternary sodium-calcium-magnesium-potassium systems. Zeolite saturated with potassium was the most effective adsorbent in removing sodium from aqueous solutions with an average removal efficiency of 69.2 and 66.5 % in binary and quaternary systems, respectively. Freundlich and Langmuir equations fitted well to experimental data in both binary and quaternary systems. Cation selectivity coefficients calculated based on the Gaines-Thomas convention varied with changing pH and adsorbent dosage. Graphical and statistical evaluations confirmed that the mechanistic cation exchange model using average Gaines-Thomas selectivity coefficients in geochemical PHREEQC program was able to successfully simulate the sodium exchange on different adsorbents in both systems. The Gaines-Thomas selectivity coefficient values greater than unity and as a consequence, the negative values of the Gibbs free energy change of adsorption indicated that sodium exchange reactions in the presence of different adsorbents used is this study were exergonic and spontaneous.
机译：进行这项研究的目的是评估低成本吸附剂（包括膨润土，高岭石和沸石，并用钙和钾，马铃薯和小麦残留物饱和）以及三种用马铃薯残留物酸性提取物功能化的金属氧化物纳米颗粒在改善苏打水质量方面的效率。 。使用含有钠，钙，镁和钾的溶液研究了诸如pH，接触时间和吸附剂用量等因素的优化。最佳pH和接触时间分别为7.0和24小时。使用官能化纳米颗粒的最佳剂量为0.1 g，使用其他吸附剂的最佳剂量为1.0 g。钠交换等温线在二元钠钙和钠钾以及季钠钙镁镁钾体系中进行。钾饱和的沸石是从水溶液中去除钠的最有效的吸附剂，在二元和四元体系中的平均去除效率分别为69.2％和66.5％。 Freundlich和Langmuir方程非常适合二元和四元系统中的实验数据。根据Gaines-Thomas惯例计算的阳离子选择性系数随pH和吸附剂剂量的变化而变化。图形和统计评估证实，在地球化学PHREEQC程序中使用平均Gaines-Thomas选择性系数的机械阳离子交换模型能够成功模拟两个系统中不同吸附剂上的钠交换。 Gaines-Thomas选择性系数值大于1，因此，吉布斯吸附自由能变化的负值表明，在本研究中使用的不同吸附剂存在下，钠交换反应是强力的和自发的。

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