不同结晶度纳米黄铁矿对亚甲基蓝吸附性能分析

Adsorption Properties of Synthetic Nano-Pyrite with Different Crystallinity for Methylene Blue

采用湿式机械化学合成法结合热处理工艺制备出不同结晶度的黄铁矿纳米颗粒,研究其对亚甲基蓝的吸附性能。利用FESEM、XRD、BET等手段对制备纳米黄铁矿的形貌、晶体结构和比表面积进行表征。考察了结晶度、亚甲基蓝初始浓度、初始pH值、干扰离子、溶解氧等对黄铁矿吸附性能的影响。结果表明,随煅烧温度的提高,黄铁矿纳米颗粒的结晶度和吸附性能分别呈现上升和下降的趋势。随亚甲基蓝初始浓度上升,FeS_(2)吸附量逐步上升并达到稳定。不同结晶度黄铁矿的最佳吸附pH值环境存在差异,随黄铁矿结晶度提升,材料最佳吸附pH值环境由酸性变为碱性。性质稳定干扰离子对吸附过程的影响较小,而碳酸根离子可使溶液保持较强的碱性环境,使材料的吸附性能提升。体系溶解氧含量通过影响黄铁矿表面氧化程度,进而产生负离子位来提高材料吸附性能。合成FeS_(2)的吸附数据与Langmuir吸附模型拟合良好,低结晶度材料符合准二级动力学模型,高结晶度材料符合准一级动力学模型。总体而言,机械化学合成的黄铁矿纳米颗粒能够高效去除水中的亚甲基蓝,具有良好的应用前景。

Pyrite nanoparticles with different crystallinity were prepared by wet mechanochemical synthesis combined with heat treatment,and their adsorption properties for methylene blue were studied.The morphology,crystal structure and specific surface area of the prepared nano-pyrite were characterized by FESEM,XRD and BET.The effects of crystallinity,initial concentration of methylene blue,initial pH,interfering ions and dissolved oxygen on the adsorption capacity of pyrite were investigated.The results showed that the crystallinity and adsorption capacity of pyrite nanoparticles increased and decreased with the increase of calcination temperature,respectively.The adsorption capacity of FeS_(2) increased gradually with the increase of initial concentration of methylene blue and eventually reached a stable value.The optimal pH environment for adsorption of pyrite with different crystallinity is different.With the increase of pyrite crystallinity,the optimal pH environment for pyrite adsorption changes from acidic to alkaline.The stable interfere ions have little influence on that adsorption process,and carbonate ions can keep the solution a strong alkaline environment and improve the adsorption performance of the pyrite.The dissolved oxygen content in the system can affect the oxidation degree of pyrite surface and produce negative ion sites,thus improving the adsorption performance of the pyrite.The adsorption data of synthesized FeS_(2) fitted well with Langmuir adsorption model.The adsorption kinetics of FeS_(2) with low crystallinity followed pseudo second order model,while that with high crystallinity followed pseudo first order model.In general,the mechanochemical synthesis of pyrite nanoparticles can effectively remove methylene blue from water,and has a good application prospect.