| 铁改性杭锦土吸附剂对水中砷的去除研究 |
| |
| 引用本文： | 蔡金水,康得军,杨天学,龚天成,陈其晓,赵颖,吕伟.铁改性杭锦土吸附剂对水中砷的去除研究[J].环境科学研究,2021,34(2):346-355. |
| |
| 作者姓名： | 蔡金水 康得军 杨天学 龚天成 陈其晓 赵颖 吕伟 |
| |
| 作者单位： | 1.福州大学土木工程学院, 福建 福州 350108 |
| |
| 基金项目： | 国家重点研发计划项目（No.2020YFC1807703）；中央级公益性科研院所基本科研业务专项（No.2019YSKY-010） |
| |
| 摘 要： | 为提高天然杭锦土对水溶液中砷的吸附性能，采用氯化铁（FeCl3·6H2O）浸渍天然黏土矿物杭锦土（HJ），制备表面负载铁氧化物的铁改性杭锦土除砷吸附剂（FHJ）.通过比表面积（BET）和扫描电镜（SEM）分析技术对材料进行表征以观察其微观形貌特点，通过X射线光电子能谱分析（XPS）和傅里叶红外光谱（FTIR）技术测定材料组成及化学基团，以初步探究材料吸附除砷机理.通过批试验考察FHJ投加量、初始pH、共存离子及腐殖酸浓度对FHJ除砷效能的影响.结果表明:①当铁负载比在0~50wt%范围内时，FHJ对溶液中As（Ⅴ）吸附容量随着铁负载比的增加而增加，最佳铁负载比为33wt%，此时铁与杭锦土的理论质量比为1:3.②BET分析结果表明经铁改性后，杭锦土比表面积显著增加，由71.14 m2/g增至158.50 m2/g；SEM分析显示，经改性后杭锦土表面形貌发生明显变化，结合Mapping图表明铁被有效负载到杭锦土表面.③批试验结果表明，As（Ⅴ）去除率随着FHJ投加量的增加而升高；溶液pH对As（Ⅴ）去除率有较大的影响，pH的降低有利于FHJ对砷酸盐的吸附.④FHJ除砷性能受溶液中共存离子CO32-、SiO32-影响较大，但受Cl-、SO42-、NO3-及腐殖酸影响程度比较小.⑤吸附动力学过程符合准二级动力学模型，Freundlich等温吸附模型可更好地描述FHJ吸附除砷行为（R2=0.999）.⑥XPS分析结果显示，铁氧化物主要以FeOOH和Fe2O3的形态负载于杭锦土表面，FTIR表明FeOOH的羟基基团同As（Ⅴ）发生吸附作用，在FHJ除砷过程中，化学吸附是主要的吸附除砷机理.研究显示，铁改性杭锦土除砷效果良好，具有一定的应用潜力.
|
| 关 键 词： | 杭锦土 改性 吸附 除砷 机理 |
| 收稿时间： | 2020/2/17 0:00:00 |
| 修稿时间： | 2020/6/10 0:00:00 |
Removal of Arsenic from Water by Iron Modified Hangjin Clay Adsorbent |
| |
| Affiliation: | 1.College of Civil Engineering, Fuzhou University, Fuzhou 350108, China2.State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China3.Jinjiang Science and Education Park of Fuzhou University, Jinjiang 362251, China4.China Environmental Resources Technology Co., Ltd. (CERT), Beijing 100012, China |
| |
| Abstract: | In order to enhance the adsorption performance of natural Hangjin clay for arsenic in water, ferric chloride (FeCl3·6H2O) is used to prepare an iron-modified Hangjin clay adsorbent (FHJ) with surface-loaded iron oxides. The adsorbent is characterized by the BET surface area analysis, scanning electron microscopy (SEM) to observe its microscopic morphology, and X-ray photoelectron spectroscopy (XPS) and Fourier infrared spectroscopy (FTIR) to determine the composition and chemical groups and to explore the mechanism of arsenic removal. The effects of adsorbent dosage, solution pH, co-existing ions and humic acid on the arsenic removal efficiency of FHJ are investigated through batch experiments. The results show that:(1) When the iron loading ratio is in the range of 0-50wt%, the adsorption capacity of As(Ⅴ) increase with the increase of the iron loading ratio. The optimal iron loading ratio is 33wt%, the theoretical mass ratio of iron to Hangjin clay is 1:3. (2) BET analysis results show that the specific surface area of Hangjin clay increases significantly from 71.14 m2/g to 158.50 m2/g after iron modification. SEM analysis manifests that the surface morphology of Hangjin clay has changed obviously after modification, and that iron is effectively loaded on the surface of Hangjin clay. (3) The batch experimental results show that arsenic removal rate increases with the increase of the amount of FHJ dosage, while the pH of the solution has a great effect on the removal rate of arsenic, and the decrease of solution pH is favorable for the adsorption of arsenate by FHJ. (4) The arsenic removal performance is greatly affected by CO32- and SiO32-, but less affected by Cl-, SO42-, NO3- and humic acid. (5) The adsorption kinetics process complies with the quasi-second-order kinetic model and the Freundlich isothermal adsorption model describes arsenic adsorption well (R2=0.999). (6) XPS analysis results indicate that iron oxides are mainly supported on the surface of Hangjin clay in the form of FeOOH and Fe2O3. FTIR demonstrates that As(Ⅴ) is adsorbed by the hydroxyl group of FeOOH. Chemisorption is the main mechanism during the process of arsenic removal by FHJ. The research suggests that iron-modified Hangjin clay exhibits excellent arsenic removal effect and has certain application potential. |
| |
| Keywords: | Hangjin clay modification adsorption arsenic removal mechanism |
|
| 点击此处可从《环境科学研究》浏览原始摘要信息 |
|
点击此处可从《环境科学研究》下载全文 |
|
