Pyrolysis And Activation Of Edible Fungi Residue And The Adsorption To OFL In Water

As the largest producer and consumer of edible fungi in the world,China produces millions of tons of edible fungi residues every year.These edible fungi residues,which can not be used reasonably,have brought great harm to the environment.In this study,edible fungi residues were pyrolyzed and activated by KOH in a high temperature tubular furnace.Their pyrolysis performance at different pyrolysis temperatures and activation performance under different activation conditions were investigated.The activated carbon obtained under the optimal conditions was used to adsorb ofloxacin in water,so as to realize the resource utilization of edible fungi residues.The main experiments and conclusions include:(1)Effect of pyrolysis temperature on three-phase products.It was found that the increase of the final pyrolysis temperature was beneficial to the preparation of hydrogen-rich gas.The maximum gas yield was 489 L·kg-1 when the final pyrolysis temperature was 900℃.Among all gas,H2 accounted for 55.55%,CO 31.93%and CH4 8.52%.Besides,choose the final pyrolysis temperature as 600℃ is more conducive to the formation of liquid phase,and the liquid yield is 27.38%.Considering the preparation of solid fuels,the final pyrolysis temperature at 500℃is favorable for the formation of solid fuels with high calorific value and high yield.Under this condition,the yield of carbon is 51.23%,and the calorific value is 20.66 MJ·kg-1.(2)Biochar prepared under 600℃,heating rate of 20℃·min-1 and reaction time of 1 h is used as the material of activation by KOH.The effects of different activation temperature,KOH/C ratio and activation time on the properties of activated carbon were investigated.The results of SEM analysis,methylene blue adsorption and iodine adsorption show that the effects of activation temperature,KOH/C ratio and activation time on the adsorption efficiency of activated carbon are inverted U-shaped distribution.The activated carbon prepared at the conditions of KOH/C ratio=1,activation time 1 h and activation temperature at 800℃ has the highest specific surface area.The yield of activated carbon is 31.20%,the specific surface area is 2095.77 m2·g-1,the methylene blue adsorption value is 615.32 mg·g-1,and the iodine adsorption value is 1563.90 mg·g-1.The activated carbon prepared under this condition was selected to adsorb antibiotics in water in the next step.(3)The effects of different adsorption parameters(adsorption temperature,solution PH and initial concentration)on the adsorption of ofloxacin in water were investigated.The results showed that the effect of PH on adsorption was normal distribution,and the adsorption capacity was highest under the neutral condition of PH=7;The increase of adsorption temperature promotes the adsorption of ofloxacin;Similarly,the adsorption capacity is proportional to the initial concentration.The higher the initial concentration is,the greater the adsorption capacity per unit mass of activated carbon goes.When under the condition of 55℃,PH=7 and initial concentration is 150 mg·L-1,the edible fungi residues activated carbon has the best adsorption capacity for ofloxacin in water.At this time,the adsorption value of ofloxacin reaches 321.40 mg·g-1.Meanwhile,the adsorption kinetics,adsorption isotherm and thermodynamics of ofloxacin on edible fungi residues activated carbon were studied.The adsorption of ofloxacin by edible fungi residue activated carbon is a spontaneous endothermic process,more in line with the Freundlich kinetic model,and is a multi-layer adsorption process.