Preparation Of Mango Bark Biochar And Its Adsorption Properties For Pyridine And Quinoline

Biochar refers to a carbon material with high carbon content and rich pore structure produced by pyrolysisof biomass under anaerobic or anoxic conditions.At present,the relationship between the preparation of biochar,structural characteristics and adsorption performance has become one of the hotspots in environmental studies.This article introduced the research advance on the preparation,structural characteristics and adsorption mechanism of biochar.Toward this end,based on the mango bark as the representative of agricultural waste,mango bark biochar was prepared by high temperature hydrothermal method and tube furnace pyrolysis method under a wide range of temperatures?300⁷00?,refered as H300^H700 and B300^B700?.The adsorption mechanism of pyridine and quinoline was studied on different biochars.In addition,the modification of biochar by Fe₂O₃ was studied,and the influencing factors of adsorption process were discussed,which provided the basis for the preparation of high performance adsorbent.The major results are presented as follows.?1?The preparation of biochar of mango bark.The mango bark biochar was prepared by the method of muffle furnace high temperature hydrothermal and tube furnace pyrolysis,and the adsorption performance of pyridine and quinoline on the two kinds of biochars was compared.Meanwhile,the effects of different carbonization temperature?300?400?500?600?700??on the adsorption process were studied.The results showed that the two kinds of biochars has some influedce on the the adsorption of pyridine and quinoline,and as the temperature rises,the smaller the effect.At the same time,the adsorption capacity of biochar was affected by pyrolysis temperature,and the adsorption capacity of pyridine and quinoline was the strongest at pyrolysis temperature of 700 ?,whose adsorption capacity were 32.110 mg/g and 33.130 mg/g respectively.Adsorption capacity has a decline when elevated reaction temperature and pH value increases.?2?Study on adsorption mechanism of pyridine and quinoline on biochar of mango bark.It was revealed that adsorption mechanism of pyridine and quinoline on biochar prepared under low pyrolysis temperature is dominated by portioning and adsorption of the biochar under high pyrolysis temperature is adsorption-dominant.The adsorption kinetics fitted well with Pseudo-second-order equation for both pyridine and quinoline,and adsorption behavior of pyridine and quinoline on the biochars can be described well by both Langmuir and Freundlich model,which illustrated that the adsorption of pyridine and quinoline on mango bark biochars is controlled by various adsorption mechanisms.?3?Modification of biochar by Fe₂O₃ nanoparticles.The specific surface area of biochar increased from 32.980 m2/g to 281.440 m2/g after modification,which greatly improved the adsorption of pyridine and quinoline.After modification,the adsorption capacity increased from 19.290 mg/g to 24.440 mg/g for pyridine and from 20.440 mg/g to 33.330 mg/g for quinoline.And the mechanism studies by Weber and Morris model show that the adsorption of pyridine on Fe₂O₃ modified biochar is controlled by the intraparticle-diffusion.