School of Materials Science and Engineering, North University of China, NO. 3 Xueyuan Road, Taiyuan, Shanxi 030051, China; Shanxi Electric Power Research Institute, NO. 6 Qingnian Road, Taiyuan, Shanxi 030001, China.
School of Materials Science and Engineering, North University of China, NO. 3 Xueyuan Road, Taiyuan, Shanxi 030051, China.
Int J Biol Macromol. 2019 Nov 1;140:1167-1174. doi: 10.1016/j.ijbiomac.2019.08.230. Epub 2019 Aug 28.
Low-cost natural polymer lignin has been widely used to remove heavy metal ions from polluted water. But it still has some shortcomings, such as poor removal performance, and weak selective adsorption. Thus, in this study, the lignin prepared by Mannich reaction with black liquor was activated with triethylenetetramine (TETA) to achieve a novel adsorbent with high adsorption rates and a strong selectivity for specific oxygen-containing anions. The adsorption capacity of activated lignin (a-CL) on three oxygen-containing anions (i.e. As(V), P(V) and Cr(VI)) was investigated systematically. The adsorption mechanism of a-CL was elucidated theoretically by the density functional theory (DFT) method. Under the same conditions, the selectivity toward oxygen-containing anions by a-CL followed P(V) < Cr(VI) < As(V). Both FT-IR and DFT simulation results revealed that the hydrogen bond between HAsO and N dominated the remarkable selectivity of As (V), yielding a maximum adsorption capacity as high as 62.5 mg g. Moreover, the adsorption was very fast with a calculated large adsorption kinetic constant. The removal of As(V) reached 100% within 60 min. The As(V) adsorption kinetics and the adsorption isotherms followed the pseudo-second-order and the Langmuir model. This study provides a way for highly selecting removal of As(VI) from polluted water with the lignin.
低成本的天然高分子木质素已被广泛用于从受污染的水中去除重金属离子。但它仍存在一些缺点，如去除性能差、选择性吸附能力弱。因此，在这项研究中，木质素通过曼尼希反应与黑液制备，然后用三亚乙基四胺（TETA）进行活化，以获得一种对特定含氧阴离子具有高吸附率和强选择性的新型吸附剂。系统研究了活化木质素（a-CL）对三种含氧阴离子（即 As(V)、P(V) 和 Cr(VI))的吸附性能。通过密度泛函理论（DFT）方法从理论上阐明了 a-CL 的吸附机理。在相同条件下，a-CL 对含氧阴离子的选择性为 P(V) < Cr(VI) < As(V)。FT-IR 和 DFT 模拟结果均表明，HAsO 与 N 之间的氢键主导了 As(V)的显著选择性，使其最大吸附容量高达 62.5mg/g。此外，吸附速度非常快，计算出的吸附动力学常数很大。在 60min 内，As(V)的去除率达到 100%。As(V)的吸附动力学和吸附等温线遵循准二级和朗缪尔模型。这项研究为木质素从受污染的水中高选择性去除 As(VI)提供了一种方法。
