School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan, China; Engineering Research Center of Biomass Materials, Ministry of Education, Mianyang 621010, Sichuan, China.
School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan, China; Engineering Research Center of Biomass Materials, Ministry of Education, Mianyang 621010, Sichuan, China.
J Hazard Mater. 2021 Feb 15;404(Pt A):124151. doi: 10.1016/j.jhazmat.2020.124151. Epub 2020 Sep 30.
Premna microphylla turcz leaves (PMTL) is a resource-rich, biodegradable, renewable biomass. Here, a microsphere adsorbent was prepared from PMTL by a self-crosslinking method without any addition of chemical cross-linking agent, and characterized by SEM, FTIR, and XPS. The influence of preparation methods and conditions on the properties of the microspheres was studied and the self-crosslinking mechanism was analyzed. The effects of temperature, pH, contact time, uranium concentration, and adsorbent dosage on its adsorption performance toward to uranium were systematically explored. The results showed that PMTL endogenous pectin binding with endogenous Ca, Mg and other metal ions to form an 'egg box' structure might be the mechanism of its self-crosslinking to form microspheres. The adsorption isotherms fitted well by the Freundlich model and the experimental maximum adsorption capacity of microspheres was 346.65 mg·g at pH of 5, and kinetics data correlated well with the pseudo-second order model. The adsorption mechanism might be the coordination bonding between the uranium and oxygen-containing groups (hydroxyl and carboxyl groups), and the ion exchange between the uranium and metal ions (mainly Ca and Mg). The PMTL microspheres are promising in treating uranium-containing wastewater in a more cost-effective and environmentally friendly manner.
苘麻叶（PMTL）是一种资源丰富、可生物降解、可再生的生物质。本研究采用自交联法，无需添加任何化学交联剂，从 PMTL 制备了一种微球吸附剂，并通过 SEM、FTIR 和 XPS 对其进行了表征。研究了制备方法和条件对微球性能的影响，并分析了自交联机制。系统研究了温度、pH 值、接触时间、铀浓度和吸附剂用量对其吸附铀性能的影响。结果表明，苘麻叶内源性果胶与内源性 Ca、Mg 等金属离子结合形成“蛋盒”结构可能是其自交联形成微球的机制。吸附等温线很好地符合 Freundlich 模型，微球的实验最大吸附容量在 pH 值为 5 时为 346.65mg·g，动力学数据与准二级模型很好地相关。吸附机制可能是铀与含氧基团（羟基和羧基）之间的配位键合，以及铀与金属离子（主要是 Ca 和 Mg）之间的离子交换。PMTL 微球有望以更具成本效益和环保的方式处理含铀废水。
