摘要
为提高纳米硫化亚铁的稳定性及其对水体Cr(Ⅵ)的还原特征,本文通过化学共沉淀法制备抗坏血酸改性纳米硫化亚铁(VC-nFeS)并阐明其对水体Cr(Ⅵ)的还原特性与机制.实验结果表明,VC-nFeS对水中的Cr(Ⅵ)具有优良的还原效果,当pH为7.0,温度为25℃,材料中还原成分FeS与废水中Cr(Ⅵ)的物质的量比为1.5∶1时,还原率可达到99%以上.VC-nFeS投加量、反应温度、初始pH值等因素都会影响Cr(Ⅵ)还原,增加投加量和提高反应温度都能够提高还原速率,酸性和中性环境更有利于Cr(Ⅵ)的还原.VC-nFeS还原Cr(Ⅵ)的过程符合伪二级动力学反应模型,主要以化学吸附为主.等温吸附实验结果表明,两者之间的反应过程用Langmuir模型拟合程度较好,该材料在25℃条件下的最大吸附容量为595.24 mg·g^(-1).扫描电镜(SEM)和Zeta电位测定结果表明,加入抗坏血酸改性能够有效分散纳米硫化亚铁.X射线衍射图谱(XRD)和红外光谱图(FTIR)结果显示,抗坏血酸改性处理能够提高纳米硫化亚铁的稳定性,并减少材料表面氧化.另外,产物表征结合水体实验结果表明反应产物主要是Cr(OH)3、Cr(Ⅲ)-Fe(Ⅲ)络合物和Cr_(2)O_(3).
In order to improve the stability of nano-FeS and its reduction characteristics of Cr(Ⅵ)for the solutions,ascorbic acid modified nano-FeS(VC-nFeS)was synthesized by chemical coprecipitation method,and the reduction mechanisms was also discussed.The results indicated that the reduction rate of VC-nFeS could reach more than 99%,when the pH was 7.0 and the temperature was 25℃,and dosage(molar ratio)of the reducing component FeS and the Cr(Ⅵ)concentration was 1.5∶1.The reduction rate increased with increasing dosage and increasing reaction temperature,acidic and neutral environment was more conducive to the reduction of hexavalent chromium.The process of Cr(Ⅵ)reduction by VC-FeS conformed to the pseudo-secondary kinetic reaction model,and its mechanism was mainly included chemical adsorption.Isothermal adsorption experiment showed that the reaction process and the Langmuir model,the maximum adsorption capacity of the material at 25℃was 595.24 mg·g^(-1).Scanning electron microscope(SEM)and Zeta potential results showed that ascorbic acid modification could effectively disperse nano ferrous sulfide,X-ray diffraction atlas(XRD)and infrared spectroscopy(FTIR)showed that ascorbate modification could improve the stability of nano ferrous sulfide,and reduced the surface oxidation of the material.In addition,the product characterization combined with the water experiment results showed that the reaction products are mainly Cr(OH)3、Cr(Ⅲ)-Fe(Ⅲ)complex and Cr_(2)O_(3).
作者
何梦婷
肖荣波
黄飞
王鹏
王韵泽
罗树华
杨洁鑫
徐美丽
HE Mengting;XIAO Rongbo;HUANG Fei;WANG Peng;WANG Yunze;LUO Shuhua;YANG Jiexin;XU Meili(School of Environmental Science and Engineering,Guangdong University of Technology,Guangzhou 511400;Guangzhou Nanyang International School,Guangzhou 510900)
出处
《环境科学学报》
CAS
CSCD
北大核心
2023年第2期61-72,共12页
Acta Scientiae Circumstantiae
基金
广东省重点领域研发计划项目(No.2019B110207001,2020B1111370001)。
