不同铁锰比例天然锰矿的改性及对As(Ⅲ)吸附和氧化的行为与机制  

Adsorption/oxidation behavior and mechanism of As(Ⅲ) by modified natural manganese ores with different Fe/Mn ratios

作　　者：田周炀 郑倩 杜晓丽 李传维 陈成 涂书新[1] TIAN Zhouyang;ZHENG Qian;DU Xiaoli;LI Chuanwei;CHEN Cheng;TU Shuxin(College of Resources and Environment,Huazhong Agricultural University,Wuhan 430070,China;Wuhan Fund Environmental Protection Co.Ltd.,Wuhan 430000,China;BCEG Environmental Remediation Co.Ltd.,Beijing 100015,China)

机构地区：[1]华中农业大学资源与环境学院,武汉430070 [2]武汉芳笛环保股份有限公司,武汉430000 [3]北京建工环境修复股份有限公司,北京100015

出　　处：《环境工程学报》2023年第2期404-415,共12页Chinese Journal of Environmental Engineering

基　　金：国家自然科学基金面上项目(42277392);国家重点研发计划(2018YFC1800305)。

摘　　要：砷污染地下水和废水严重影响人体健康和生态环境,开发新型砷污染水体的修复材料具有重要意义。含铁锰矿来源广,具有较高的砷吸附容量和氧化特性,常用于吸附去除水体砷污染。但是,天然铁锰矿成分复杂,杂质含量多,对砷的吸附容量小,通常需要改性以提高其除砷性能。以不同铁锰含量比例的天然锰矿为材料,研究了水合肼改性法提高天然铁锰矿砷吸附容量的效果,采用批处理法研究了影响改性铁锰矿吸附砷的过程和影响因子,并结合XPS和FTIR等光谱学手段探究改性天然铁锰矿对As(Ⅲ)的去除机制。结果表明,两种不同铁锰比例的改性天然铁锰矿对砷的吸附容量分别为30.9 mg·g^(-1)和12 mg·g^(-1),远高于未改性的材料。改性后的材料对As(Ⅲ)的吸附过程符合二级动力学模型,等温吸附曲线符合Freundlich模型。影响因子结果表明,共存离子PO_(4)^(3-)、SiO_(3)^(2-)、CO_(3)^(2-)对不同铁锰比改性材料去除As(Ⅲ)均有抑制作用。4种材料的pHpzc均小于6。pH为1~9时,2种改性含铁锰矿As去除率在94%以上,而pH>9时,材料对砷的去除率显著降低。FT-IR分析发现,改性后材料的H—O—H和Mn—O特征峰增宽增强,谱线变得平滑,表明改性后材料表面部分杂质被溶解去除,暴露出更多的活性位点。XPS分析发现,改性后材料吸附As(Ⅲ)后低价态锰含量增加,而Fe^(2+)、Fe^(3+)所占百分含量变化不大,说明不同铁锰比改性材料在吸附As(Ⅲ)过程中Mn将As(Ⅲ)氧化为As(Ⅴ),Fe主要参与吸附反应。以上研究结果可为水体砷污染修复技术的开发提供参考。Arsenic-contaminated groundwater and wastewater seriously affect human health and ecological environment, and it is important to develop new remediation materials for arsenic-contaminated water bodies.Ferromanganese ore has a wide source, high arsenic adsorption capacity and oxidation characteristics, and is commonly used to adsorb and remove arsenic pollution from water bodies. However, natural ferromanganese ores have complex compositions, high impurity content and low adsorption capacity for arsenic, and usually need to be modified to improve their arsenic removal performance. In this study, natural manganese ores with different iron and manganese content ratios were used as materials to investigate the effect of hydrazine hydrate modification on arsenic adsorption capacity of natural ferromanganese ores. The process and influencing factors affecting arsenic adsorption of modified ferromanganese ores were studied by batch processing method, and the related removal mechanism of As(Ⅲ) was explored by XPS, FTIR and other spectroscopic means. The results showed that the arsenic adsorption capacities of two modified natural ferromanganese ores with different Fe/Mn ratios were 30.9 mg·g^(-1)and 12 mg·g^(-1), respectively, which were much higher than those of the unmodified materials. The adsorption process of As(Ⅲ) by the modified material conformed to the second-order kinetic model, and the isothermal adsorption curves were in accordance with the Freundlich model. The experimental results of influence factors showed that the coexisting ions of PO_(4)^(3-), SiO_(3)^(2-)and CO_(3)^(2-)all inhibited As(Ⅲ) removal by the modified materials with different iron manganese ratios. The pHpzc of all the four materials were lower than 6, and the As removal rates of the two modified materials were above 94% at pH 1~9, while decreased significantly at pH>9. FT-IR analysis showed that the H—O—H and Mn—O characteristic peaks of the modified materials were broadened and enhanced, and the spectral lines became smooth,

关 键 词：改性 天然铁锰矿 砷 吸附 氧化 

分 类 号：X703[环境科学与工程—环境工程]