Wu Ling, Qi Shuang, Zhang Tingwei, Jin Yongcan, Xiao Huining
Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing 210037, China.
Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing 210037, China; International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China.
Carbohydr Polym. 2024 Apr 15;330:121832. doi: 10.1016/j.carbpol.2024.121832. Epub 2024 Jan 19.
In this work, new N, O-codoped chitosan-derived carbon adsorbents (CKC-x, x refer to the calcination temperature) were synthesized over a simple process of chitosan-KOH aerogel production and simultaneous carbonization/activation of the aerogel. CKC-700 was characterized by sheet-like morphology (even containing a portion of carbon nano-sheet of 3 nm thickness), high porosity and specific surface area (1702.1 m/g), and pyridinic/pyrrolic/graphitic N groups. The simultaneous carbonization/activation of chitosan-KOH aerogel prepared by top-down coagulation of chitosan aqueous solution by KOH aqueous solution rendered these beneficial characteristics. CKC-700 exhibited a superior adsorption capacity for Rhodamine B (RhB) to other chitosan-derived carbon adsorbents, and the maximum adsorption capacity for RhB of 594 mg/g was achieved at 55 °C. CKC-700 also possessed reasonable reusability for the removal of RhB, and the removal efficiency was still above 95 % in the fifth cycle. The effects of adsorption temperature and time, adsorbent dose, organic dye concentration, and solution pH on the adsorption capacity of CKC-700 were studied. Moreover, the adsorption isotherm, kinetics, thermodynamics, and the adsorption mechanism of RhB on CKC-700 were discussed. In addition, CKC-700 also showed favorable adsorption performance for methylene blue (441 mg/g), methyl orange (457 mg/g), and congo red (500 mg/g) at around 25 °C.
在本工作中，通过壳聚糖 - 氢氧化钾气凝胶制备以及气凝胶同时碳化/活化的简单过程，合成了新型氮、氧共掺杂的壳聚糖基碳吸附剂（CKC - x，x表示煅烧温度）。CKC - 700具有片状形态（甚至包含一部分厚度为3nm的碳纳米片）、高孔隙率和比表面积（1702.1m²/g）以及吡啶型/吡咯型/石墨型氮基团。壳聚糖水溶液与氢氧化钾水溶液通过自上而下的凝聚法制备壳聚糖 - 氢氧化钾气凝胶并同时进行碳化/活化，赋予了这些有益特性。CKC - 700对罗丹明B（RhB）的吸附能力优于其他壳聚糖基碳吸附剂，在55°C下对RhB的最大吸附容量达到594mg/g。CKC - 700对RhB的去除还具有合理的可重复使用性，在第五个循环中去除效率仍高于95%。研究了吸附温度、时间、吸附剂用量、有机染料浓度和溶液pH对CKC - 700吸附容量的影响。此外，还讨论了CKC - 700对RhB的吸附等温线、动力学、热力学以及吸附机理。此外，在约25°C时，CKC - 700对亚甲基蓝（441mg/g）、甲基橙（457mg/g）和刚果红（500mg/g）也表现出良好的吸附性能。
