N-Acetyl-l-cysteine-functionalized lignin (CFL) was synthesized via UV-initiated thiol–ene click reaction. The structure and morphology of CFL were characterized by FT-IR, ¹H NMR, and SEM. Influences of the pH, dosage, contact time, concentration, and temperature on metal ions adsorption onto CFL were analyzed. Because of the introduction of more adsorption sites, the maximum adsorption capacities of CFL for Cu(II) and Pb(II) could reach 68.7 and 55.5 mg/g, which were 12.5 and 7.6 times that of raw lignin, respectively. The results from adsorption kinetics and isotherms suggest that the metal ions were adsorbed onto CFL by a monolayer chemisorption mechanism. The chemical interactions between CFL and metal ions through chelation were studied and confirmed by FT-IR and XPS analysis. The feasible construction of CFL through UV-initiated reaction has proven to be a promising “clickable” method in synthesizing lignin-based functional materials with designed modules and enhanced adsorption abilities for metal ions removal.

中文翻译：

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巯基合成半胱氨酸功能化木质素，以增强对Cu（II）和Pb（II）的吸附

N-乙酰基-1-半胱氨酸官能化的木质素（CFL）是通过UV引发的硫醇-烯点击反应合成的。FT-IR表征了CFL的结构和形态，¹1 H NMR和SEM。分析了pH，剂量，接触时间，浓度和温度对金属离子吸附到CFL上的影响。由于引入了更多的吸附位，CFL对Cu（II）和Pb（II）的最大吸附容量可以达到68.7和55.5 mg / g，分别是粗木质素的12.5和7.6倍。吸附动力学和等温线的结果表明，金属离子是通过单层化学吸附机制吸附到CFL上的。研究了CFL和金属离子通过螯合的化学相互作用，并通过FT-IR和XPS分析证实。通过UV引发的反应构建CFL的可行方法已被证明是合成具有设计模块和增强的金属离子吸附能力的木质素基功能材料的有前途的“可点击”方法。