竹基N、P共掺杂活性炭的制备及其镧离子吸附性能  

Preparation of Bamboo-based N,P Co-doped Activated Carbon and Its Lanthanum Ion Adsorption Performance

作　　者：王贵龙 刘艳艳 江荣源 李思敏 林冠烽[1] 卢贝丽 黄彪[1] 陈燕丹[1] WANG Gui-long;LIU Yan-yan;JIANG Rong-yuan;LI Si-min;LIN Guan-feng;LU Bei-li;HUANG Biao;CHEN Yan-dan(College of Material Engineering,Fujian Agriculture and Forestry University,Fuzhou 350002,China)

机构地区：[1]福建农林大学材料工程学院,福州350002

出　　处：《环境科学》2023年第12期6823-6832,共10页Environmental Science

基　　金：福建省自然科学基金项目(2021J01108);国家自然科学基金项目(31870561,32171726);福建省林业科技推广项目(2022TG18)。

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La^(3+).分析了活化温度和pH值对La^(3+)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La^(3+)吸附量的关键.其中,石墨氮可以提供La^(3+)—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La^(3+)提供活性位点.La^(3+)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La^(3+)/Na^(+)和La^(3+)/Ca^(2+)共存体系中对La^(3+)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%.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 La^(3+)in aqueous solutions.The effects of activation temperature and pH value on the adsorption performance of La^(3+)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 La^(3+).Among them,graphitic nitrogen could provide interactions between La^(3+)-π bonds,and C-P=O and C/P-O-P could provide active sites for the adsorption of La^(3+)through complexation and electrostatic interaction.The adsorption of La^(3+)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 La^(3+)in the La^(3+)/Na^(+)and La^(3+)/Ca^(2+)coexistence systems reached 93.49% and 82.49%,respectively.Additionally,the removal efficiency remained above 54% after five successive adsorption-desorption cycle experiments.

关 键 词：竹基活性炭 N、P共掺杂 磷酸氢二铵 活化 一步热解 

分 类 号：X131[环境科学与工程—环境科学]