Department of Chemistry and Center for Research in Energy and Environment, Missouri University of Science and Technology, Rolla, MO, 65409, USA; Center for Single Nanoparticle, Single Cell, Single Molecule Monitoring, Missouri University of Science and Technology, Rolla, MO, 65409, USA.
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
Chemosphere. 2021 Jan;262:127940. doi: 10.1016/j.chemosphere.2020.127940. Epub 2020 Aug 9.
Sodium hydroxide treated rice hulls were investigated to preconcentrate, remove, and recover metal ions including Be, Al, Cr, Co, Ni, Cu, Zn, Sr, Ag, Cd, Ba, and Pb in both batch mode and column mode. Sodium hydroxide treatment significantly improved the removal efficiency for all metal ions of interest compared to the untreated rice hull. The removal kinetics were extremely fast for Co, Ni, Cu, Zn, Sr, Cd, and Ba, which made the treated rice hull a promising economic green adsorbent to preconcentrate, remove, and recover low-level metal ions in column mode at relatively high throughput. The principal removal mechanism is believed to be the electrostatic attraction between the negatively charged rice hulls and the positively charged metal ions. pH had a drastic impact on the removal for different metal ions and a pH of 5 worked best for most of the metal ions of interest. Processed rice hulls provide an economic alternative to costly resins that are currently commercially available products designed for metal ion preconcentration for trace metal analysis, and more importantly, for toxic heavy metal removal and recovery from the environment.
氢氧化钠处理的稻壳被用于在批处理和柱处理模式下预浓缩、去除和回收包括铍、铝、铬、钴、镍、铜、锌、锶、银、镉、钡和铅在内的金属离子。与未经处理的稻壳相比，氢氧化钠处理显著提高了所有目标金属离子的去除效率。对于钴、镍、铜、锌、锶、镉和钡，去除动力学非常快，这使得处理后的稻壳成为一种很有前途的经济型绿色吸附剂，可在相对较高的流量下通过柱处理模式预浓缩、去除和回收低浓度的金属离子。主要的去除机制被认为是带负电荷的稻壳与带正电荷的金属离子之间的静电吸引。pH 值对不同金属离子的去除有很大的影响，pH 值为 5 时对大多数目标金属离子效果最佳。处理后的稻壳为目前市售的昂贵树脂提供了一种经济替代方案，这些树脂专门用于痕量金属分析中的金属离子预浓缩，更重要的是，用于从环境中去除和回收有毒重金属。
