不同Mn/Fe比例天然含铁锰矿的As(Ⅲ)吸附性能与机制
As(Ⅲ)adsorption performance and mechanisms of natural Fe-bearing manganese ores with different Mn/Fe ratios
田周炀 1郑倩 1杜晓丽 2陈成 3李传维 3涂书新1
作者信息
- 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
- 折叠
摘要
水体中的砷主要以亚砷酸(As(Ⅲ))形态存在.金属氧化物常用于水体砷的去除,但其对As(Ⅲ)的亲和力较弱,导致水体砷很难去除,因此,寻求高效、廉价、绿色的除As(Ⅲ)材料具有显著的环境意义.天然含铁锰矿是一种高效的砷吸附剂,由于自然形成条件复杂,其不同含铁锰矿对As(Ⅲ)的去除性能存在较大差异.本研究以两种不同Mn/Fe比例的天然含铁锰矿(NFM-L、NFM-H)为研究对象,评估其对As(Ⅲ)的吸附性能,并结合XPS、XRD等光谱学表征手段探究其砷的去除机制.实验结果表明,NFM-L的Fe含量是NFM-H的5.61倍,其As(Ⅲ)的最大吸附量(24.82 mg·g-1)与吸附速率亦显著高于NFM-H(18.94 mg·g-1),NFM-L和NFM-H对As(Ⅲ)的等温吸附曲线更符合Freundlich模型.影响因子实验表明,溶液pH值对NFM-L的影响更大,共存离子H2PO4 能够显著抑制两种材料对As(Ⅲ)的吸附,但是材料粒径对As(Ⅲ)去除的影响较小.光谱学表征发现,两种矿物吸附砷后结构并未发生明显变化,但锰氧化物能将As(Ⅲ)氧化为As(Ⅴ),从而显著提高了铁锰矿对砷的吸附能力.
Abstract
Arsenic in water is mainly present in the form of arsenite(As(Ⅱ)).Metal oxides are commonly used for arsenic removal in water,but their affinity with As(Ⅲ)is weak,making it difficult to remove arsenic from water.Therefore,seeking efficient,inexpensive,and environmentally friendly As(Ⅱ)removal materials is of great environmental significance.Natural iron-manganese-containing minerals are efficient arsenic adsorbents,but different iron-manganese-containing minerals have significantly different As(Ⅱ)removal performances due to their complex natural formation conditions.In this study,two natural iron-manganese-containing minerals with different Mn/Fe ratios(NFM-L and NFM-H)were selected as research subjects to evaluate their adsorption performances for As(Ⅲ).XPS,XRD,and other spectroscopic characterization methods were used to explore the arsenic removal mechanism.The results showed that the Fe content of NFM-L was 5.61 times that of NFM-H,and its maximum adsorption capacity for As(Ⅲ)(24.82 mg·g-1)and adsorption rate were significantly higher than that of NFM-H(18.94 mg·g-1).And the isothermal adsorption curves for As(Ⅲ)by NFM-L and NFM-H were more consistent with the Freundlich model.The influence factor experiments showed that the solution pH had a greater impact on NFM-L,and the coexisting ion H2PO4-could significantly inhibit the adsorption of As(Ⅲ)by both materials,while material particle size had a smaller effect on As(Ⅲ)removal.Spectroscopic characterization showed that the structure of the two minerals did not change significantly after arsenic adsorption,but manganese oxide could oxidize As(Ⅲ)to As(Ⅴ),significantly enhancing the adsorption capacity of iron-manganese-containing minerals for arsenic.In conclusion,this study revealed the arsenic removal mechanism of natural iron-manganese-containing minerals,providing theoretical support for the exploration of efficient,inexpensive and environmentally friendly As(Ⅲ)removal materials and offering new ideas for the treatment of arsenic pollution in water environments.
关键词
天然含铁锰矿/As(Ⅲ)/Mn/Fe/氧化/吸附Key words
natural iron manganese ore/As(Ⅲ)/Mn/Fe/oxidation/adsorption引用本文复制引用
基金项目
国家自然科学基金(42277392)
国家重点研发计划(2018YFC1800305)
出版年
2024
NETL
NSTL
万方数据