一步法制备桉木废弃物基磁性活性炭的磁性、孔结构和表面特性调控机制

Eucalyptus wood processing generates a large amount of residues. Magnetic activated carbon has the characteristics of fast magnetic separation recovery and separation. Magnetic activated carbon will be prepared from Eucalyptus residues magnetization with different kinds of magnetization agents and activation with chemicals under different conditions such as carbonization activation temperature, time, pressure and so on. The performance such as adsorption properties, pore structure, microcrystal structure, chemical composition, surface morphology, surface chemistry and magnetic properties of the produced activated carbon will be characterized by The iodine value, methylene blue adsorption, phenol adsorption and N2 adsorption, XRD, XPS, SEM, TEM, FTIR, Raman spectroscopy, vibrating sample magnetometer(VSM). The relationship between the chemical composition, magnetic properties, pore structure, surface properties of activated carbon and magnetization agents, activating agents and activation conditions will be established. The magnetic properties production, change rule and regulation mechanism as well as synergy mechanism of pore adjustment between activating agents and magnetization agents will be revealed. The pyrolysis characteristics and reaction mechanism of Eucalyptus residues after added a magnetization agent or activating agent will be analyzed by methods such as pyrolysis gas chromatography mass spectrometry(Py-GC/MS), thermogravimetric analysis (TG) coupled with Fourier transform infared spectrometry(FTIR), thermogravimetric analysis(TG) and differential thermal analysis(DTA), differential scanning calorimetry(DSC) etc. The research results will provide the technical and theoretical basis for the resource utilization of Eucalyptus residues, and it will also promote the high value utilization of agricultural and forestry waste biomass resources, which has both academic value and economic significance.

桉树木材生产产生大量废弃物。磁性活性炭具有快速磁选回收分离特点。本项目拟在桉木废弃物添加不同赋磁剂、活化剂，在不同的炭化活化温度、时间、压力等条件下一步制备磁性活性炭；采用碘值、亚甲基蓝吸附值、苯酚吸附值和氮气吸附、XRD、XPS、SEM、TEM、FTIR、拉曼光谱、振动样品磁强计(VSM)测定技术表征不同条件制备的活性炭的吸附性能、孔隙结构、微晶结构、化学组成、表面形貌、表面化学和磁性，建立活性炭的物质组成、磁性、孔结构、表面特性与赋磁剂、活化剂和活化条件之间的联系，揭示磁性产生的机理、变化规律和调控机制以及活化剂和赋磁剂的协同调孔机制；用热解气相色谱质谱联用、热重红外光谱联用、热重分析和差热分析、差示扫描量热等方法分析桉木废弃物添加赋磁剂、活化剂后的热解特性和反应机理。研究结果为桉木废弃物资源化利用提供技术和理论依据，也将促进农林废弃物生物质的资源化高值化利用，既有学术价值又有经济意义

桉树木材生产产生大量废弃物。磁性活性炭具有快速磁选回收分离特点。本项目在桉木屑添加FeCl3、FeCl2等赋磁剂, ZnCl2、K2CO3、KOH等活化剂一定温度、时间等条件下一步制备磁性活性炭(MAC)；采用碘值、亚甲基蓝吸附值、苯酚吸附值和氮气吸附、XRD、XPS、SEM、TEM、FTIR、拉曼光谱、VSM表征MAC的吸附性能、孔结构、化学组成和磁性，建立MAC的物质组成、磁性、孔结构、表面特性与赋磁剂、活化剂和活化条件之间的联系，揭示磁性产生的机理、变化规律和调控机制以及活化剂和赋磁剂的协同调孔机制。结果表明：FeCl3、FeCl2等赋磁剂, ZnCl2、KCO3、KOH等活化剂相结合，在一定的温度、时间等条件下可以一步制备出性能优良的MAC，制备的MAC可用于吸附有机色素或者催化光解有机色素污染物；MAC的磁性、孔结构可通过调节磁化剂、活化剂种类及其与桉木屑的比例，加热温度和时间等条件来调节，引入磁性物质会减少MAC的孔隙体积，增加活化剂量、提高温度延长时间能增加MAC孔隙体积；形成的磁性物质有Fe2O3、Fe3O4、Fe3C和Fe等，且在不同温度条件下得到的磁性物质和磁性不同。如以K2CO3为活化剂、FeCl3为赋磁剂，在MAC调孔调磁时发现：在氯化铁与桉木屑的质量比为0.5 (mFeCl3:mES=0.5)，碳酸钾与桉木屑的质量比为3.5（mK2CO3:mES=3.5），炭化活化时间为3h时，随着炭化活化温度从500℃升高到700℃时，比饱和磁化强度Ms从30.27emu/g升高到174.82emu/g，SBET从496.74m2/g升高的1271.90m2/g；在炭化活化温度为750℃，时间为3h，mK2CO3:mES=3时，随mFeCl3:mES= 0.25、0.5、0.75、1、1.25、1.5变化，制备的MAC SBET从1619.05m2/g降到714.40m2/g，Ms从39.10emu/g升到169.30emu/g (mFeCl3:mES=1) 又降到101.60emu/g (mFeCl3:mES=1.5)；MAC的磁性物质主要为Fe3O4，也有Fe和Fe3C，在炭化活化温度高于750℃时，Fe3C生成。研究结果为桉木废弃物资源化利用提供技术和理论依据，也将促进农林废弃物生物质的资源化高值化利用，既有学术价值又有经济意义.