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 (pHPZC), sorption kinetics, and adsorption capacity. The most appropriate adsorbent concentration was 5 g/L, and sorption studies were carried out at pH 5.0 (pHPZC = 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 (SCexp) 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, Qmax 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.

中文翻译：

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巴西棕榈（Copernicia prunifera）棕榈树生物质作为水介质中Pb（II）和Cd（II）的吸附剂。

评估了从Copernicia prunifera（Mill。）HE Moore（巴西棕榈）物种的外果皮获得的植物基生物量（CFB（巴西棕榈果生物量））在水介质中作为潜在有毒金属的吸附剂的可行性。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Zeta电位对CFB进行了表征，以研究生物吸附剂的形态及其与Pb和Pb的水溶性金属离子的相互作用光盘。生物质呈现出具有负的ζ电势（-2.59 mV）的无定形结构，并且存在诸如OH，COC，CH和C = O的官能团。Pb（II）和Cd（II）的去除潜力在间歇系统中进行，测试了单质溶液和单元素溶液，以评估吸附剂剂量和初始金属离子浓度，零电荷点的pH（pHPZC），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，在pH 5.0（pHPZC = 4.68）下进行吸附研究，其中吸附剂表面显示负电荷，有利于金属离子的吸附。动力学研究表明，伪二级模型最适合实验数据，在接触时间120分钟时达到平衡。铅和镉的实验吸附容量（SCexp）分别约为28和34 mg / g，并使用六个不同的非线性等温线模型来描述吸附现象，其中四个具有2个参数，即Langmuir， Freundlich，Temkin和Dubinin-Radushkevich（DR），分别具有两个带有3个参数的参数，即SIPS和Hill。非线性Temkin和Freundlich等温模型分别最适合Pb（II）和Cd（II）的实验数据。根据Langmuir模型，Pb（II）和Cd（II）的Qmax分别为26 mg / g和58 mg / g，表明CFB作为传统方法去除潜在有毒金属的新方法的效率水性介质。