Chemical Engineering Department, Federal University of Pernambuco (UFPE), 1235 Prof. Moraes Rego Avenue, Cidade Universitária, Recife, Pernambuco, 50670-901, Brazil.
Center of Biosciences, Federal University of Pernambuco (UFPE), W/N Prof. Moraes Rego Avenue, Cidade Universitária, Recife, Pernambuco, 50670-420, Brazil.
Environ Sci Pollut Res Int. 2019 Oct;26(28):28593-28602. doi: 10.1007/s11356-018-3139-z. Epub 2018 Sep 10.
Graphene oxide (GO) was synthetized from graphite oxidation via the modified Hummers method. Afterwards, the GO was functionalized with diethylenetriamine (DETA) and FeCl to obtain the novel amino-iron oxide functionalized graphene (GO-NH-FeO). FTIR, XRD, SEM with EDX, and Raman spectroscopy were performed to characterize both GO and GO-NH-FeO. The GO-NH-FeO was then evaluated as adsorbent of the cationic dye Methylene Blue (MB); analysis of the point of zero net charge (pH) and pH effect showed that the GO-NH-FeO pH was 8.2; hence, the MB adsorption was higher at pH 12.0. Adsorption kinetics studies indicated that the system reached the equilibrium state after 5 min, with adsorption capacity at equilibrium (q) and kinetic constant (k) of 966.39 mg g and 3.17∙10 g mg min, respectively; moreover, the pseudo-second-order model was better fitted to the experimental data. Equilibrium studies showed maximum adsorption capacity of 1047.81 mg g; furthermore, Langmuir isotherm better fitted the adsorption. Recycling experiments showed that the GO-NH-FeO maintained the MB removal rate above 95% after 10 cycles. All the results showed sorbent high adsorption capacity and outstanding regeneration capability and evidenced the employment of novel GO-NH-FeO as a profitable adsorbent of textile dyes.
氧化石墨烯（GO）是通过改良的 Hummers 法从石墨氧化合成的。随后，GO 与二乙烯三胺（DETA）和 FeCl 反应，得到新型氨基氧化石墨烯（GO-NH-FeO）。采用傅里叶变换红外光谱（FTIR）、X 射线衍射（XRD）、扫描电子显微镜（SEM）和能谱（EDX）以及拉曼光谱对 GO 和 GO-NH-FeO 进行了表征。然后，将 GO-NH-FeO 用作阳离子染料亚甲蓝（MB）的吸附剂；零电荷点（pH）和 pH 效应分析表明，GO-NH-FeO 的 pH 值为 8.2；因此，MB 在 pH 12.0 时的吸附更高。吸附动力学研究表明，该体系在 5 分钟后达到平衡状态，平衡时的吸附容量（q）和动力学常数（k）分别为 966.39 mg/g 和 3.17∙10 g/mg·min；此外，伪二阶模型更符合实验数据。平衡研究表明最大吸附容量为 1047.81 mg/g；此外，Langmuir 等温线更好地拟合了吸附。循环实验表明，GO-NH-FeO 在 10 次循环后仍保持超过 95%的 MB 去除率。所有结果表明，该吸附剂具有高吸附容量和出色的再生能力，证明了新型 GO-NH-FeO 可作为一种有利的纺织染料吸附剂。
