铜基氮碳微球对废水中盐酸四环素的吸附性能

Adsorption of tetracycline in wastewater by copper-based nitrogen-carbon microspheres

以水溶性低相对分子质量壳聚糖(0.1000 g)为碳源和氮源,Cu(NO_(3))_(2)·3H_(2)O(0.2174、0.2899、0.6522 g)为铜源,采用一步水热法制备了3种铜基氮碳微球Cu-x/NC(x=1、2、3),通过SEM、FTIR、XRD、Raman光谱和BET对Cu-x/NC进行了表征,通过静态吸附实验考察了Cu-x/NC对盐酸四环素(TC)的吸附性能,并测定了吸附动力学、吸附等温线和吸附热力学参数,测试了Cu-x/NC抗离子干扰、pH稳定性和循环吸附性能。结果表明,Cu-x/NC呈规整的球形结构,表面有含氧和含氮基团,并均匀分布着Cu元素;在25℃吸附温度和24h吸附时间的条件下,Cu-2/NC(5 mg)表现出吸附TC的最大平衡吸附容量(1993.42 mg/g);Cu-2/NC吸附TC符合Langmuir等温线模型和准二级动力学模型,吸附过程是自发、吸热过程;TC溶液中存在NaCl不会降低Cu-2/NC吸附TC的平衡吸附容量,TC溶液在p H=5.5时对吸附最有利;7次循环吸附测试中,Cu-2/NC对TC表现出较为稳定的去除率(95.84%~86.67%);Cu-2/NC吸附TC依靠的主要作用力有氢键、Cu阳离子桥、电子供体-受体相互作用以及静电作用。

Three copper-based nitrogen-carbon microspheres Cu-x/NC(x=1,2,3)were successfully synthesized by a one-step hydrothermal method using water-soluble low relative molecular mass chitosan(0.1000 g)as carbon and nitrogen sources,copper nitrate trihydrate(0.2174,0.2899,0.6522 g)as copper sources,characterized by SEM,FTIR,XRD,Raman spectroscopy and BET,and then evaluated via static adsorption experiments for their tetracycline hydrochloride(TC)adsorption performance,of which the adsorption kinetics,adsorption isotherms and thermodynamic parameters as well as the resistance to ion interference,pH stability and cyclic adsorption performance were further analyzed.The results showed that Cu-x/NC exhibited a regular spherical structure with oxygen-containing and nitrogen-containing groups on the surface and a uniform distribution of Cu elements.Cu-2/NC(5 mg)exhibited the maximum adsorption capacity for TC(1993.42 mg/g)at 25℃for 24 h,and followed the Langmuir isotherm model and pseudo-second-order kinetic model,with a spontaneous and endothermic adsorption process.The presence of NaCl in TC solution didn't reduce the equilibrium adsorption capacity of Cu-2/NC toward TC,and TC solution at pH=5.5 was most favorable for adsorption.In the 7-cycle adsorption tests,Cu-2/NC showed a relatively stable removal rate to TC(95.84%~86.67%).The main driving force for TC adsorption by Cu-2/NC was attributed to hydrogen bond,Cu cation bonding bridge,electron donor-acceptor interaction and electrostatic interactions.