摘要
活性炭具有比表面积高、孔隙结构发达、表面官能团丰富、化学性质稳定等优点,是水处理中常用的吸附剂.吸附饱和的活性炭需从水中分离并进行再生处理以供重复利用.但传统分离方法耗时长、收率低、成本高,难以高效地将吸附饱和的活性炭从水中分离,在一定程度上限制了活性炭在水处理中的应用.通过对活性炭进行赋磁处理可制备得到吸附容量高、易于分离回收的磁性活性炭.同时,磁性活性炭具有良好的催化活性,可用于在高级氧化反应中高效降解水中有机污染物.因此,磁性活性炭在水处理领域具有广阔的应用前景.本工作主要介绍了磁性活性炭制备方法、微观结构和物化性质,综述了磁性活性炭在污水治理方面的研究进展,总结了磁性活性炭的吸附特性和再生方法,并对磁性活性炭在水处理中的发展趋势进行了展望.
Abstract
Activated carbon(AC)has the characteristics of high specific surface area,porosity,abundant surface functional groups and chemical stability,and these advantages make it a widely used adsorbent in water treatment.After being exhausted(saturated adsorption contaminants),the spent AC needs to be separated from aquatic systems and regenerated which is conductive to materials recycling.However,it is difficult to efficiently separate the powder AC saturated adsorption contaminants from aquatic systems by traditional separation methods(gravitational sedimentation,centrifugation,filtration,and flotation),and the disadvantages for these methods root in many aspects including time-consuming,high-cost,and low separation efficiency.These limit the wide application of activated carbon in the field of water treatment to some extent.Magnetic modification treatment on AC can provide a magnetic activated carbon(MAC)which possesses better performances reflecting in higher adsorption capacity,and can be easier,rapid and efficient separation through external magnetic fields.At the same time,MAC has good catalytic activity,which is useful for enhancing the capability of advanced oxidation process to efficiently degrade organic pollutants in aquatic systems.Therefore,MAC has broad application prospects in the field of water treatment.This work mainly introduces the preparation methods(co-precipitation method,thermochemical method,and mechanical milling method),microstructure and physicochemical properties(specific surface area,pore structure,magnetism,crystal and chemical structure,surface charge)of MAC.The research progress of MAC in wastewater treatment in recent years is reviewed,consisting of organic pollutant removal,heavy metal removal and other applications.The adsorption characteristics(adsorption isotherms and adsorption dynamics)and corresponding influencing factors(adsorption temperature,solution pH,and coexisting ions)are summarized in details.And the regeneration methods of AC are investigated comprehensively.In the end,the development and prospect of the application of MAC in water treatment are also discussed.
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