| 引用本文: | 梁梦思,曹耀武,孙伟浩,杨晨,郭清海.机械化学法合成羟基插层Mg/Fe型层状双氢氧化物[J].材料科学与工艺,2021,29(3):33-41.DOI:10.11951/j.issn.1005-0299.20200030. |
| LIANG Mengsi,CAO Yaowu,SUN Weihao,YANG Chen,GUO Qinghai.Hydroxyl-intercalated Mg-Fe-LDH synthesized by a mechanochemical method[J].Materials Science and Technology,2021,29(3):33-41.DOI:10.11951/j.issn.1005-0299.20200030. |
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| 机械化学法合成羟基插层Mg/Fe型层状双氢氧化物 |
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梁梦思1,2,曹耀武1,2,孙伟浩1,2,杨晨1,2,郭清海1,2
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(1.生物地质与环境地质国家重点实验室(中国地质大学(武汉)),武汉430074); 2.中国地质大学(武汉) 环境学院,武汉 430074)
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| 摘要: |
| Mg/Fe型层状双氢氧化物(LDH)是一类可有效去除水中有害组分(特别是有害阴离子)的无机吸附材料。常用的共沉淀法在合成层状双氢氧化物过程中容易产生大量碱性废水,且合成产物通常结晶度较低。本文利用改进的机械化学合成法,选取MgO和无定形态的Fe(OH)3作为反应前驱物,成功制备出了羟基(—OH)插层的Mg/Fe型层状双氢氧化物(Mg-Fe-OH-LDH)。通过对合成产物的XRD、SEM、FT-IR及比表面积分析,探究了研磨时间、研磨条件及晶化时间等实验参数对产物晶体结构的影响。结果表明:在前期机械研磨过程中对MgO和无定形态的Fe(OH)3混合物进行强烈的撞击和搅拌,可以诱发化学反应并合成目标产物,使用高能行星球磨仪研磨仅1.5 h即可生成高纯度的Mg-Fe-OH-LDH；晶化过程加快后期合成产物的晶粒发育,晶化48 h后的Mg-Fe-OH-LDH晶粒呈规整的薄片型,孔隙发育,且层间主要为羟基和水分子,化学结构式为Mg2.96Fe(OH)8.94·0.942H2O,比表面积为42.8 m2/g；在25 ℃条件下,对磷酸根和刚果红的单分子层最大吸附量分别为64.44和97.61 mg/g。综上,通过该方法可经济、高效地大批量生产Mg-Fe-OH-LDH,同时避免了掺杂可能产生二次污染的其他阴离子组分,有望应用于大规模的水污染处理。 |
| 关键词: Mg/Fe型层状双氢氧化物 机械化学法 晶化 前驱物 吸附 |
| DOI：10.11951/j.issn.1005-0299.20200030 |
| 分类号:TB333 |
| 文献标识码:A |
| 基金项目:国家自然科学基金资助项目(41772370,41861134028,41572335). |
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| Hydroxyl-intercalated Mg-Fe-LDH synthesized by a mechanochemical method |
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LIANG Mengsi1,2, CAO Yaowu1,2, SUN Weihao1,2, YANG Chen1,2, GUO Qinghai1,2
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(1.State Key Laboratory of Biogeology and Environmental Geology (China University of Geosciences(Wuhan)), Wuhan 430074,China;2.School of Environmental Studies, China University of Geosciences(Wuhan), Wuhan 430074,China)
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| Abstract: |
| Mg-Fe-layered double hydroxide(Mg-Fe-LDH)is an inorganic compound capable of effectively removing harmful constituents (especially harmful anions) from water. The commonly used co-precipitation method always produces a large amount of alkaline wastewater during the synthesis of LDH, and the products usually feature a low crystallization as well. In this study, an improved mechanochemical method was used to synthesize hydroxyl-intercalated Mg-Fe-LDH (i.e. Mg-Fe-OH-LDH) by selecting MgO and amorphous Fe(OH)3 as reaction precursors. The products were characterized using XRD, SEM, FT-IR and specific surface area measurement to investigate the effects of experimental synthetic conditions, including milling time, milling equipment and crystallization time, on their crystal structures. Results show that a strong collision and stir of the mixture of MgO and amorphous Fe(OH)3 in the early milling process could stimulate the occurrence of the expected chemical reaction, resulting in the synthesis of the target product. Highly pure Mg-Fe-OH-LDHs could be generated via milling in 1.5 h with a high-energy planetary ball mill. The later stage of the crystallization process which speeded up the further growth of the formed crystal particles. After 48 h of crystallization, the obtained Mg-Fe-OH-LDH crystals were regularly lamellar, pore-developed, and intercalated primarily by hydroxyls and water molecules with a chemical formula of Mg2.96Fe(OH)8.94·0.942H2O.The BET surface area was 42.8 m2/g, and the maximum monolayer adsorption capacity for phosphate and Congo red was 64.44 mg/g and 97.61 mg/g at 25 ℃, respectively. Based on the proposed method, Mg-Fe-OH-LDH can be produced in large quantities economically and efficiently, while avoiding the doping of other anion components that may cause secondary pollution, and is expected to be applied to large-scale water pollution treatment. |
| Key words: Mg-Fe-LDH mechanochemical method crystallization precursors adsorption capacity |
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