碳点修饰磷酸钴微米花对水中四环素的吸附

Adsorption of tetracycline in water onto carbon-dots modified cobalt phosphate micro-flower

抗生素废水的肆意排放对人类健康和生态环境产生潜在的威胁.吸附技术被认为是处理此类污染物最有效的方法之一.本研究通过简单的共沉淀法制备碳点修饰的磷酸钴微米花复合材料(CDs-CoPi),并用其吸附去除水溶液中四环素(TC).采用XRD、XPS、FT-IR、SEM等手段对CDs-CoPi的晶相、结构、形貌和元素组成等进行表征分析.结果表明,CDs均匀地负载在CoPi微米花的表面,CDs-CoPi的比表面积显著提高,对TC的吸附性能显著增强,CDs16-CoPi(CDs质量分数为16%)显示出最优异的吸附性能.CDs16-CoPi对TC的吸附过程符合伪二阶动力学模型.等温吸附规律可用Langmuir模型很好地描述,最大单分子层吸附容量可达34.7 mg/g.CDs-CoPi对TC的吸附性能提升主要归因于CDs表面含氧官能团的贡献.

The indiscriminate discharge of antibiotic wastewater poses a huge threat to human health and the ecological environment.Adsorption technology is considered to be one of the effective ways to deal with such contaminants.Here,carbon dot modified cobalt phosphate micro-flower composites(CDs/CoPi)were prepared through a facile co-precipitation method for adsorption removal of tetracycline(TC)from aqueous solution.The crystal phase,structure,morphology and element composition of the CDs/CoPi composite were analyzed by a series of characterization methods such as XRD,XPS,FT-IR and SEM.The results show that the CDs were uniformly deposited on the surfaces of CoPi microflowers in the composite which can improve the specific surface area of CoPi and effectively improve its adsorption performance of TC.The CDs/CoPi composites as adsorbents exhibit enhanced adsorption behavior for TC in comparison of pure CoPi,in which the CDs16-CoPi(with the CDs mass content of 16%)shows the highest adsorption activity.The corresponding adsorption kinetics was fitted well with the pseudo-second-order kinetic model.Meanwhile,the adsorption isotherm research showed that the measured experimental data are in accord with the Langmuir model,and the maximum single-layer adsorption capacity of the CDs16-CoPi composite was calculated to be(34.7 mg/g).The increased adsorption performance of CDs/CoPi can attribute to the rich oxygen-containing groups on the surface of CDs.