School of Chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran.
Department of Chemical Engineering, Tarbiat Modares University, Tehran, Iran.
J Environ Health Sci Eng. 2014 Dec 12;12(1):148. doi: 10.1186/s40201-014-0148-9. eCollection 2014.
The adsorption equilibria of toluene from aqueous solutions on natural and modified diatomite were examined at different operation parameters such as pH, contact time, initial toluene concentration was evaluated and optimum experimental conditions were identified. The surface area and morphology of the nanoparticles were characterized by SEM, BET, XRD, FTIR and EDX analysis. It was found that in order to obtain the highest possible removal of toluene, the experiments can be carried out at pH 6, temperature 25°C, an agitation speed of 200 rpm, an initial toluene concentration of 150 mg/L, a centrifugal rate of 4000 rpm, adsorbent dosage = 0.1 g and a process time of 90 min. The results of this work show that the maximum percentage removal of toluene from aqueous solution in the optimum conditions for NONMD was 96.91% (145.36 mg/g). Furthermore, under same conditions, the maximum adsorption of natural diatomite was 71.45% (107.18 mg/g). Both adsorption kinetic and isotherm experiments were carried out. The experimental data showed that the adsorption follows the Langmuir model and Freundlich model on natural and modified diatomite respectively. The kinetics results were found to conform well to pseudo-second order kinetics model with good correlation. Thus, this study demonstrated that the modified diatomite could be used as potential adsorbent for removal of toluene from aqueous solution.
考察了不同操作参数（如 pH 值、接触时间、初始甲苯浓度等）下天然和改性硅藻土从水溶液中吸附甲苯的吸附平衡。通过 SEM、BET、XRD、FTIR 和 EDX 分析对纳米颗粒的表面积和形貌进行了表征。结果表明，为了获得尽可能高的甲苯去除率，可以在 pH 值为 6、温度为 25°C、搅拌速度为 200 rpm、初始甲苯浓度为 150 mg/L、离心速度为 4000 rpm、吸附剂用量为 0.1 g 和处理时间为 90 min 的条件下进行实验。研究结果表明，在最佳条件下，NONMD 从水溶液中去除甲苯的最大百分比为 96.91%（145.36 mg/g）。此外，在相同条件下，天然硅藻土的最大吸附量为 71.45%（107.18 mg/g）。进行了吸附动力学和等温线实验。实验数据表明，吸附分别遵循天然和改性硅藻土上的朗缪尔模型和弗伦德利希模型。动力学结果与准二级动力学模型吻合较好，相关性较好。因此，本研究表明改性硅藻土可用作从水溶液中去除甲苯的潜在吸附剂。
