Departamento de Química, Universidade Estadual do Ceará, Fortaleza, Ceará, 60.714-903, Brazil.
Laboratório de Materiais Poliméricos e Biossorventes, Universidade Federal de São Carlos, Araras, 13600-970, Brazil.
Environ Sci Pollut Res Int. 2021 Apr;28(15):18941-18952. doi: 10.1007/s11356-020-07635-5. Epub 2020 Jan 14.
Plant-based biomass (CFB (carnauba fruit biomass)) obtained from the fruit exocarp of the species Copernicia prunifera (Mill.) H.E. Moore (carnauba) was evaluated for its viability as an adsorbent of potentially toxic metals in aqueous medium. The CFB was characterized by powder X-ray spectroscopy (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and zeta potential to investigate the morphology of the biosorbent and its interaction with water soluble metal ions of Pb and Cd. The biomass presents an amorphous structure, with negative zeta potential (- 2.59 mV), and the presence of functional groups such as O-H, C-O-C, C-H, and C=O. The removal potential of Pb(II) and Cd(II) was performed in a batch system, and monoelement solutions were tested to assess the effects of adsorbent dose and initial metal ion concentration, pH at the point of zero charge (pH), sorption kinetics, and adsorption capacity. The most appropriate adsorbent concentration was 5 g/L, and sorption studies were carried out at pH 5.0 (pH = 4.68), in which the surface of the adsorbent shows negative charges and favors the adsorption of metal ions. Kinetic studies showed that the pseudo-second order model best fit the experimental data, and equilibrium was reached at 120 min of contact time. The experimental sorption capacity (SC) for Pb and Cd was around 28 and 34 mg/g, respectively, and six different non-linear isotherm models were used to describe the sorption phenomena, among them, four with 2 parameters, i.e., Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich (DR), respectively, and two with 3 parameters, namely, SIPS and Hill. The non-linear Temkin and Freundlich isotherm models best fit the experimental data for Pb(II) and Cd(II), respectively. According to the Langmuir model, Q was 26 mg/g and 58 mg/g for Pb(II) and Cd(II), respectively, indicating the efficiency of CFB as a new alternative to conventional methods for the removal of potentially toxic metals from aqueous medium.
从物种 Copernicia prunifera (Mill.) H.E. Moore 的果实外果皮中获得的基于植物的生物质 (CFB (巴西棕榈果实生物质)) 被评估为在含水介质中吸附潜在有毒金属的能力。通过粉末 X 射线光谱 (XRD)、扫描电子显微镜 (SEM)、傅里叶变换红外光谱 (FTIR) 和 ζ 电位对 CFB 进行了表征，以研究生物吸附剂的形态及其与水溶性金属离子 Pb 和 Cd 的相互作用。生物质呈现无定形结构，ζ 电位为负 (-2.59 mV)，并且存在 O-H、C-O-C、C-H 和 C=O 等官能团。在分批系统中进行了 Pb(II) 和 Cd(II) 的去除潜力测试，并测试了单元素溶液以评估吸附剂剂量和初始金属离子浓度、零电荷点 (pH)、吸附动力学和吸附容量的影响。最合适的吸附剂浓度为 5 g/L，并且在 pH 5.0 (pH = 4.68) 下进行了吸附研究，其中吸附剂表面带负电荷，有利于金属离子的吸附。动力学研究表明，准二级模型最适合实验数据，接触时间为 120 分钟时达到平衡。Pb 和 Cd 的实验吸附容量 (SC) 分别约为 28 和 34 mg/g，使用六种不同的非线性等温线模型来描述吸附现象，其中四种具有 2 个参数，即 Langmuir、Freundlich、Temkin 和 Dubinin-Radushkevich (DR)，另外两种具有 3 个参数，即 SIPS 和 Hill。非线性 Temkin 和 Freundlich 等温线模型分别最适合 Pb(II) 和 Cd(II) 的实验数据。根据 Langmuir 模型，Pb(II) 和 Cd(II) 的 Q 值分别为 26 mg/g 和 58 mg/g，表明 CFB 作为从含水介质中去除潜在有毒金属的传统方法的新替代方法具有效率。
