摘要
为探索高效且快速去除水溶液中Cd^(2+)的方法,以二乙基二硫代氨基甲酸钠(DDTC)为改性剂,制得一种新型磁性螯合纳米材料(Fe_(3)O_(4)@SiO_(2)-DDTC)。通过X射线衍射(XRD)、扫描电镜(SEM)和傅里叶红外(FT-IR)等手段进行表征分析,并设计批量吸附试验。结果表明,Fe_(3)O_(4)@SiO_(2)-DDTC粒径为115~125 nm,饱和磁化强度为25.74 emu·g^(-1)。经DDTC改性后,Fe_(3)O_(4)@SiO_(2)-DDTC对Cd^(2+)的吸附能力得到有效提升,且在pH值4~8较宽范围内,可实现对Cd^(2+)的有效吸附。由于Cd^(2+)的吸附位位于Fe_(3)O_(4)@SiO_(2)-DDTC的最外层,Cd^(2+)的吸附脱附均较快,5 min内可达到吸附平衡量的82%,2 h后达到吸附平衡,符合准二级动力学模型。吸附等温线更符合Langmuir模型,在45℃条件下,Fe_(3)O_(4)@SiO_(2)-DDTC对Cd^(2+)的理论最大吸附量为45.52 mg·g^(-1)。材料对Cd^(2+)吸附是以单分子层化学吸附为主,并伴有物理吸附过程。材料的重复使用性能试验显示,经4次循环使用后,Fe_(3)O_(4)@SiO_(2)-DDTC对Cd^(2+)仍具有良好的吸附效果,表明其良好的重用性。本研究结果为磁性纳米材料在Cd废水处理方面的应用提供了理论依据。
To explore an efficient and rapid method for Cd^(2+) removal from aqueous solutions, a novel magnetic core-shell structure nanomaterials(Fe_(3)O_(4)@SiO_(2)-DDTC) was synthesized and modified with sodium diethyldithiocarbamate(DDTC). Fe_(3)O_(4)@SiO_(2)-DDTC composites was characterized using X-ray diffraction(XRD), scanning electron microscope(SEM) and Fourier transform infrared spectrometry(FT-IR). To investigate the adsorption properties of materials, batch adsorption experiments were designed. The results showed that the particle size of Fe_(3)O_(4)@SiO_(2)-DDTC was 115~125 nm, and the saturation magnetization was 25.74 emu·g^(-1). The adsorption ability of the material was significantly improved with DDTC modifying, and effective adsorption was achieved in a wide range of pH range of 4~8. As the adsorption site of Cd^(2+) was located in the outermost layer of Fe_(3)O_(4)@SiO_(2)-DDTC, the adsorption and desorption of Cd^(2+) were relatively fast, exceeding 80% of the adsorption equilibrium within 5 min, and reaching the adsorption equilibrium after 2 hours. The whole adsorption process conformed to the pseudo-second-order model. The adsorption isotherm was more consistent with the Langmiur model, with a maximum adsorption capacity of 45.52 mg·g^(-1)(45℃). The results of adsorption mechanism analysis showed that the adsorption process of Fe_(3)O_(4)@SiO_(2)-DDTC for Cd^(2+) removal was dominated by chemical adsorption, while accompanied by physical adsorption. After desorption and regeneration for 4 cycles with thiourea-nitric acid solution, Fe_(3)O_(4)@SiO_(2)-DDTC still had a good adsorption effect on Cd^(2+). Recycle tests showed that the material still had significant Cd^(2+) removal capability for four successive adsorption-desorption cycles, indicating that Fe_(3)O_(4)@SiO_(2)-DDTC had high reusability. The results of this study can provide a theoretical basis for the application of magnetic nanomaterials in cadmium wastewater treatment.
作者
郭晓婧
张志毅
郭掌珍
GUO Xiaojing;ZHANG Zhiyi;GUO Zhangzhen(College of Resources and Environment,Shanxi Agricultural University,Taigu,Shanxi 030801)
出处
《核农学报》
CAS
CSCD
北大核心
2021年第7期1707-1716,共10页
Journal of Nuclear Agricultural Sciences
基金
土壤环境与养分资源山西省重点实验开放基金项目(2017003)
山西省自然科学基金项目(2015011082)。
