State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
Sci Total Environ. 2021 Apr 15;765:144427. doi: 10.1016/j.scitotenv.2020.144427. Epub 2021 Jan 5.
A series of actinia-shaped lignin-based adsorbents (LNAEs) featuring lignin (LN) as the core and grafted poly(acrylic acid) (PAA) as the tentacle were designed and fabricated. Two fluoroquinolones (FQs) with similar molecular structures, ofloxacin (OFL) and ciprofloxacin (CIP), were used as targets to study the selective adsorption performance of LNAEs associated with the structural effects of the LN-based adsorbents in FQs binary aqueous system. The adsorption of the two FQs by LNAEs complied with the competitive Langmuir isothermal model, and showed selective removal of CIP over OFL due to the additional negative charge-assisted hydrogen bond (CAHB) formed between the carboxyl group of LNAEs and the secondary amino group of CIP, in addition to the effects of electrostatic attraction and normal hydrogen bonds, according to quantitative studies and density functional theory analysis. A binary nonlinear model based on phenomenological theory was applied to study the effects of PAA branched-chain length and distribution on the selective adsorption performance of the LN-based adsorbents. Accordingly, the branched-chain distribution played a more important role and higher distribution density of branched PAA could expose more adsorption sites on LNAEs' surface and improve the adsorptive selectivity. This study offers a well understanding of the structure-activity relationship of the surface grafting-modified adsorbents in binary pollutant systems and fundamental guidance for the exploitation and design of novel and efficient adsorbents.
一系列具有 actinia 形状的木质素基吸附剂（LNAEs）被设计和制造，其特点是以木质素（LN）为核心，接枝聚（丙烯酸）（PAA）为触手。选择两种具有相似分子结构的氟喹诺酮类（FQs），氧氟沙星（OFL）和环丙沙星（CIP），作为目标物，研究与 LN 基吸附剂结构效应相关的在 FQs 二元水体系中 LNAEs 的选择性吸附性能。两种 FQs 通过 LNAEs 的吸附符合竞争 Langmuir 等温模型，并且由于 LNAEs 的羧基与 CIP 的仲氨基之间形成了额外的负电荷辅助氢键（CAHB），除了静电吸引和正常氢键的影响之外，LNAEs 对 CIP 表现出选择性去除 OFL 的作用，根据定量研究和密度泛函理论分析。应用基于唯象理论的二元非线性模型研究了 PAA 支链长度和分布对 LN 基吸附剂选择性吸附性能的影响。因此，支链分布起着更重要的作用，较高的支化 PAA 分布密度可以在 LNAEs 表面暴露更多的吸附位点，并提高吸附选择性。这项研究深入了解了二元污染物体系中表面接枝改性吸附剂的结构-活性关系，并为新型高效吸附剂的开发和设计提供了基础指导。
