College of Chemistry, Jilin University, 130026 Changchun, PR China.
Talanta. 2012 May 15;93:350-7. doi: 10.1016/j.talanta.2012.02.051. Epub 2012 Mar 1.
In this work, graphene oxide (GO) was firstly prepared, following by element analysis. Glutaraldehyde cross-linked chitosan (GCCS) and chitosan/graphene oxide (CSGO) composite with three different amounts of GO (5 wt%, 10 wt% and 15 wt%) were also prepared for the adsorption of Au(III) and Pd(II) in aqueous solution. The properties of the adsorbents were investigated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and surface area analysis. Batch adsorption studies were carried out. The adsorption of Au(III) and Pd(II) onto CSGO composites was optimum at pH 3.0-5.0 for Au(III) and pH 3.0-4.0 for Pd(II), which was much wider than that of GCCS. The adsorption isotherms obeyed the Langmuir isotherm models for the adsorption of Au(III) and Pd(II). Chitosan with 5 wt% graphene oxide (CSGO(5)) composite had the largest adsorption capacity for Au(III) and Pd(II) compared with the other prepared adsorbents, where the maximum adsorption capacity were 1076.649 mg/g for Au(III) and 216.920 mg/g for Pd(II), respectively. The adsorption kinetics of Au(III) and Pd(II) onto CSGO(5) followed a pseudo-second-order kinetic model, indicating that the chemical adsorption was the rate-limiting step. Thermodynamic parameters, such as Gibbs energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°), were calculated, showing that the adsorption of Au(III) and Pd(II) onto CSGO(5) were spontaneous, endothermic and feasible. The desorption studies of Au(III) and Pd(II) onto CSGO(5) showed that CSGO(5) can be used repeatedly without significantly changing its adsorption capacity and desorption percentage after 3 cycles. Besides CSGO(5) was successfully applied for the determination and separation of Au(III) and Pd(II) in ore samples.
在这项工作中，首先制备了氧化石墨烯（GO），随后进行了元素分析。还制备了戊二醛交联壳聚糖（GCCS）和三种不同 GO 含量（5wt%、10wt%和 15wt%）的壳聚糖/氧化石墨烯（CSGO）复合材料，用于吸附水溶液中的 Au(III)和 Pd(II)。通过傅里叶变换红外光谱（FT-IR）、X 射线衍射（XRD）和表面积分析研究了吸附剂的性质。进行了批量吸附研究。对于 Au(III)，CSGO 复合材料对 Au(III)和 Pd(II)的吸附最佳 pH 值为 3.0-5.0，对于 Pd(II)，最佳 pH 值为 3.0-4.0，比 GCCS 宽得多。吸附等温线符合 Langmuir 等温线模型，用于吸附 Au(III)和 Pd(II)。与其他制备的吸附剂相比，壳聚糖负载 5wt%氧化石墨烯（CSGO(5))复合材料对 Au(III)和 Pd(II)的吸附容量最大，最大吸附容量分别为 1076.649mg/g 和 216.920mg/g。Au(III)和 Pd(II)在 CSGO(5)上的吸附动力学符合准二级动力学模型，表明化学吸附是限速步骤。计算了热力学参数，如吉布斯自由能（ΔG°）、焓（ΔH°）和熵（ΔS°），表明 CSGO(5)对 Au(III)和 Pd(II)的吸附是自发的、吸热的和可行的。Au(III)和 Pd(II)在 CSGO(5)上的解吸研究表明，CSGO(5)在 3 次循环后，其吸附容量和解吸百分比没有明显变化，可重复使用。此外，CSGO(5)成功应用于矿石样品中 Au(III)和 Pd(II)的测定和分离。
