摘要
利用尿素和乙二胺四乙酸钠盐通过一步法低温固相裂解合成了二维纳米碳氮材料(2-D CNx),实现了对水中重金属离子的吸附去除。系统地研究了2-D CNx对水中重金属离子Cd2+、Pb2+和Cu2+的吸附性能,其吸附动力学过程均符合准二级动力学模型,吸附等温线更符合Langmuir模型。结果表明:Cd2+、Cu2+和Pb2+的初始浓度均为40 mg·L-1,在25℃下,达到平衡时吸附量分别达到了79.4、58.5、72.8 mg·g-1;2-D CNx在比较广泛的pH范围(3.0~9.0)内对重金属离子都具有比较好的吸附效果;吸附剂在吸附柱过滤穿透实验中表现出很好的吸附效果和可重复利用性,且具有良好的机械稳定性。进一步的机理分析探明,吸附主要基于材料表面的羟基和重金属离子交换及氨基与重金属离子的络合协同作用。
2-D CNx nanosheets were synthesized successfully via one-step solid-phase pyolysis of urea and EDTA at low temperature, and they were used to remove heavy metal ions from water. Batch adsorption experiments were conducted to systematically investigate the removal performance of Cd2+, Pb2+ and Cu2+. The results showed that the kinetics of heavy metal ions removal by 2-D CNx nanosheets followed the pesudosecond-order model, and the adsorption isotherms process followed Langmuir model. At the initial concentration of 40 mg·L-1 for Cd2+, Pb2+ or Cu2+, their maximum adsorption capacities on 2-D CNx nanosheets were 79.4,58.5, 72.8 mg·g-1 when the temperature was 25 ℃, respectively. The 2-D CNx nanosheets had a high adsorption performance in a wide pH range of 3.0~9.0. Further, the column sorption test indicated that the adsorbents presented good adsorption effect, mechanical stability and reusability. The adsorption mechanism of heavy metals ions onto 2-D CNx nanosheets was mainly controlled by the ion exchange between carboxyl groups and the complexation between amino groups and heavy metal ions.
作者
张开胜
蔡兴国
孔令涛
刘锦淮
ZHANG Kaisheng;CAI Xingguo;KONG Lingtao;LIU linhuai(Nano-Materials and Environmental Detection Lab,Institute of Intelligent Machines,Chinese Academy of Sciences,Hefei 230031,China)
出处
《环境工程学报》
CAS
CSCD
北大核心
2020年第4期884-895,共12页
Chinese Journal of Environmental Engineering
基金
国家自然科学基金资助项目(21976182,61573334)
中国-斯里兰卡水技术研究与示范联合中心项目
中国科学院中国-斯里兰卡联合科教中心
安徽省重点研究与开发计划项目(1704a0802136)
安徽省科技重大专项(18030801104,17030901069)
国家重大科学研究计划纳米专项(2011CB933700)
中国科学院重点部署项目(KFZD-SW-309)。
关键词
二维纳米材料
氮化碳
纳米吸附剂
吸附
重金属离子
two-dimensional nanomaterials
carbon nitride
nano-adsorbents
adsorption
heavy metal ions
