| 竹基N、P共掺杂活性炭的制备及其镧离子吸附性能 |
| 摘要点击 2531 全文点击 710 投稿时间：2022-11-23 修订日期：2023-02-19 |
| 查看HTML全文
查看全文 查看/发表评论 下载PDF阅读器 |
| 中文关键词 竹基活性炭 N、P共掺杂 磷酸氢二铵 活化 一步热解 |
| 英文关键词 bamboo-based activated carbon N, P co-doping diammonium hydrogen phosphate activation one-step pyrolysis |
| DOI 10.13227/j.hjkx.20231236 |
|
| 中文摘要 |
| 采用磷酸氢二铵为活化剂和N、P源，竹屑为碳源，通过一步热解法制备N、P共掺杂活性炭，并将其用于高效去除水溶液中的La3+.分析了活化温度和pH值对La3+吸附性能的影响，并通过TG-IR、SEM-EDX、孔隙结构、XPS以及亲水性等探究其活化和吸附机制.结果表明，磷酸氢二铵在高温下容易分解产生氨气和磷酸，对物料起到活化作用，促进活性炭比表面积和孔隙容积的提高；作为N、P源，磷酸氢二铵的添加成功实现了活性炭的N、P共掺杂，而含N、P官能团的引入是提升La3+吸附量的关键.其中，石墨氮可以提供La3+—π键间的相互作用，C—P＝O和C/P—O—P可通过络合作用和静电作用为吸附La3+提供活性位点.La3+在N、P共掺杂活性炭上的吸附是吸热和自发的，吸附过程符合Langmuir等温式和二级动力学模型.在活化温度为900℃，pH=6的工艺条件下，N、P共掺杂活性炭的吸附量高达55.18 mg·g-1，比未掺杂样品高2.53倍，并且其在La3+/Na+和La3+/Ca2+共存体系中对La3+的吸附选择性分别达到93.49%和82.49%，经过5次连续的吸附-解吸循环实验去除效率仍高于54%. |
| 英文摘要 |
| Using diammonium hydrogen phosphate as an activator and N and P source and and bamboo chips as the carbon source, N, P co-doped activated carbon was prepared by one-step pyrolysis and used to efficiently remove La3+ in aqueous solutions. The effects of activation temperature and pH value on the adsorption performance of La3+ were analyzed, and the activation and adsorption mechanisms were explored using TG-IR, SEM-EDX, pore structure, XPS, and hydrophilicity. The results showed that diammonium hydrogen phosphate easily decomposed at a high temperature to produce ammonia and phosphoric acid, which activated the material and promoted the increase in the specific surface area and pore volume of the activated carbon. As an N and P source, the addition of diammonium hydrogen phosphate successfully achieved the N, P co-doping of activated carbon, and the introduction of N- and P-containing functional groups was the key to enhance the adsorption of La3+. Among them, graphitic nitrogen could provide interactions between La3+-π bonds, and C-P=O and C/P-O-P could provide active sites for the adsorption of La3+ through complexation and electrostatic interaction. The adsorption of La3+ on N, P co-doped activated carbons was endothermic and spontaneous, and the adsorption process conformed to the Langmuir isotherm and secondary kinetic model. Under the process conditions of an activation temperature of 900℃ and pH=6, the adsorption capacity of the N, P co-doped activated carbon was as high as 55.18 mg·g-1, which was 2.53 times higher than that of the undoped sample, and its adsorption selectivity for La3+ in the La3+/Na+and La3+/Ca2+ coexistence systems reached 93.49% and 82.49%, respectively. Additionally, the removal efficiency remained above 54% after five successive adsorption-desorption cycle experiments. |
|
|
|
