ABSTRACT

In this study, a novel composite aerogel of Nicandra physaloides(L.) Gaertn seed, gum/graphene oxide (NPG/GO), was prepared by using a vacuum freeze drying method for methylene blue (MB) adsorption. The techniques, including Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), were adopted for studying the structure and surface characteristics of NPG/GO, with thermogravimetric analysis (TGA) being adopted for testing thermal properties. The effects of pH value, initial dye concentration, temperature and adsorbent dosage on adsorption performance were elaborately analysed. The adsorption kinetic studies showed that the process of adsorption follows Langmuir isotherm and a pseudo-second-order kinetic model. When the mass ratio of NPG to GO was 1.25:1, the adsorption capacity was the highest. According to Langmuir isotherm, the maximum adsorption capacity of 408.16 mg/g was higher than that of NPG. The specific surface area and average pore diameter of NPG/GO was measured as 2.70 m²/g and 4.8 nm, respectively. Thermodynamic analysis revealed that the adsorption process of methylene blue on NPG/GO was a spontaneous and endothermic process. In general, the prepared nanocomposites were excellent candidates for adsorption and removal process because of simple synthesis, low cost, high efficiency, non-toxicity, environment protection and degradability.

摘要

在这项研究中，Nicandra physaloides(L.) Gaertn的新型复合气凝胶种子树胶/氧化石墨烯 (NPG/GO) 采用真空冷冻干燥法制备亚甲基蓝 (MB) 吸附。采用 Brunauer-Emmett-Teller (BET)、扫描电子显微镜 (SEM) 和傅里叶变换红外光谱 (FTIR) 等技术研究 NPG/GO 的结构和表面特性，并采用热重分析 (TGA)用于测试热性能。详细分析了pH值、染料初始浓度、温度和吸附剂用量对吸附性能的影响。吸附动力学研究表明，吸附过程遵循朗缪尔等温线和准二级动力学模型。当NPG与GO的质量比为1.25:1时，吸附量最高。根据朗缪尔等温线，408.16 mg/g的最大吸附量高于NPG。NPG/GO的比表面积和平均孔径为2.70 m² /g 和 4.8 nm，分别。热力学分析表明，亚甲基蓝在 NPG/GO 上的吸附过程是一个自发的吸热过程。总的来说，制备的纳米复合材料具有合成简单、成本低、效率高、无毒、环保和可降解等优点，是吸附和去除工艺的理想选择。