Abstract

The natural Polygonum cognatum (P. cognatum) was utilized as a selective biosorbent for the biosorption of methylene blue (MB) from dye mixtures (MB/RhB and MB/MO), separately. P. cognatum was characterized by using SEM–EDX, FT-IR, TGA, BET surface area and zeta measurement techniques. The effects of diverse parameters on the biosorption were investigated, and the kinetic and isotherm models were applied to obtain data to exhibit the biosorption mechanism. The characterization results showed that P. cognatum had various functional groups and also roughness, irregularity and cavities on the structure with the BET surface area of 57.65 m²/g. P. cognatum biosorbed the MB selectively with an attractive efficiency from MB/RhB and MB/MO mixtures and the maximum biosorption capacity of P. cognatum was calculated as 426.39 mg g⁻¹ for MB at pH ~ 5. The selective biosorption could be ascribed to the electrostatic and weak interactions between smaller cationic dye (MB) and negatively charged biosorbent surface with a zeta potential value of − 26.30 mV at pH 5. The pseudo-second order kinetic and Langmuir isotherm models have well-defined the biosorption process. Moreover, P. cognatum showed high biosorption (97.54%) and desorption (100%) efficiencies after ten repeated cycles for MB biosorption. P. cognatum with a high biosorption capacity could be a reusable biosorbent for the selective MB biosorption from dye mixtures.

Graphical abstract

Polygonum cognatum (P. cognatum) selectively biosorbed MB over RhB and MO from the dye mixtures with the maximum biosorption capacity of 426.39 mg g⁻¹. The selective biosorption could be attributed to the electrostatic and weak interactions between smaller cationic dye (MB) and negatively charged biosorbent surface. P. cognatum showed highly reusability after ten repeated cycles for MB biosorption.

中文翻译：

---

高度可重复使用的植物基生物吸附剂，可从水性介质中的染料混合物中选择性地进行亚甲基蓝生物吸附

摘要

天然何首乌（P. cognatum）被用作选择性生物吸附剂，分别用于从染料混合物（MB / RhB和MB / MO）生物吸附亚甲基蓝（MB）。通过使用SEM-EDX，FT-IR，TGA，BET表面积和zeta测量技术对白兰地酒进行了表征。研究了各种参数对生物吸附的影响，并应用动力学和等温线模型获得数据以展示生物吸附机理。表征结果表明，白果假单胞菌具有各种官能团，并且在BET表面积为57.65m ² / g的结构上还具有粗糙度，不规则性和空洞。白兰地在MB〜RhB和MB / MO混合物中有选择性地吸附了MB，并产生了诱人的吸附效率，算出pH〜5时MB对银的最大生物吸附量为426.39 mg g ^-1。以及较小的阳离子染料（MB）与带负电的生物吸附剂表面之间的弱相互作用，在pH 5时zeta电位值为− 26.30 mV。伪二级动力学模型和Langmuir等温线模型已很好地定义了生物吸附过程。此外，在十个重复的MB生物吸附循环后，白兰地衣菌显示出高的生物吸附（97.54％）和解吸（100％）效率。白兰地 具有高生物吸附能力的吸附剂可能是一种可重复使用的生物吸附剂，用于从染料混合物中选择性进行MB生物吸附。

图形概要

何首乌（P. cognatum）从染料混合物中选择性地吸附了RhB和MO上的MB，最大吸附量为426.39 mg g ^-1。选择性生物吸附可归因于较小的阳离子染料（MB）与带负电荷的生物吸附剂表面之间的静电相互作用和弱相互作用。在十个重复的MB生物吸附循环后，干邑假单胞菌显示出高度的可重复使用性。