In this paper,ZnSO4-impregnated biochar(PRZn)was subjected to high temperature(60℃ and 90℃)abiotic aging for six months.The characteristics of biochar properties after aging were determined by elemental analyzer,specific surface area analyzer,X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy.The effect of aging on the adsorption performance of Pb2+was comparatively studied with aged biochars and pristine biochars.The results indicated the free radicals(methyl radicals)generated by high temperature aging process led to the increasing of oxygen-containing functional groups content on the surface of biochars.The specific surface area of biochars pyrolyzed under 500℃ was greatly increased after aging(from 24.67m2/g to 85.51m2/g),while Zn oxides introduced from modification process were transformed from crystal structures to organic bound forms.The adsorption capacity of Pb2+was increased from 31.18mg/g to 47.70mg/g because of aging processes.However,a slight decrease of oxygen functional groups and Pb2+adsorption capacity(36.05mg/g decreased to 31.92mg/g)was observed for biochars pyrolyzed under 700℃ after ageing at high temperature(90℃),mainly because a self-quenching effect of reactive substances at high ageing temperature and a stable structure for biochar pyrolyzed at 700℃.Findings of this study can provide new insights to the long-term utilization of modified biochar in lead-contaminated soil.
关键词
Zn改性生物炭/Pb吸附/非生物化学老化/长期利用/自由基
Key words
Zn modified biochars/adsorption of Pb2+/abiotic aging/long-term utilization/free radicals
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