Study On Preparation Of Pig Bone Char And Its Enhanced Anaerobic Fermentation Of Corn Straw

Improper treatment of dead livestock and poultry is not conducive to the development of animal husbandry in the direction of high quality,but also hinders the process of ecological civilization construction.The resource utilization of dead livestock and poultry is very important.Preparation of biochar is an effective treatment method,and biochar as an additive can improve the performance of anaerobic fermentation.The preparation of pig bone char from dead pigs has a broad prospect as an additive for anaerobic fermentation.In this paper,pig bone char was prepared by KOH activation method with pig bone as raw material,which was used as additive to mediate anaerobic fermentation to enhance its gas production characteristics.The conclusions are as follows:(1)Pig bone char with large specific surface area and rich functional groups was obtained by specific surface area,functional groups and electrical conductivity.In the experiment,the process parameters which directly affect the physicochemical properties of pig bone char,such as activation temperature,activation time,pickling times and impregnation ratio,were selected as experimental factors.Nine groups of orthogonal experimental groups were designed at three levels,and the specific surface area,functional groups and electrical conductivity of nine groups of pig bone char were tested and analyzed.The results of specific surface area showed that the specific surface area and pore volume of all experimental groups were higher than that of raw materials,and the average pore size of experimental group was lower than that of raw materials.When the activation temperature is 600?,the activation time is 30 min,the impregnation ratio is 2,and the pickling time is one time,the specific surface area of pig bone charcoal is the highest,145.89 m2/g,which is 55.37 times higher than the raw material.The pore structure of pig bone char is mainly distributed in the range of 2?10 nm,and the peak value is about 2 nm,which belongs to mesoporous materials.Through the analysis of Fourier transform infrared spectroscopy,it was found that pig bone charcoal contains P-O,C-O-C,C=C,C=O and-OH functional groups.The results of range analysis showed that the factors affecting the specific surface area were as follows:impregnation ratio>pickling times>activation time>activation temperature.The order of influencing factors on the conductivity of bone char is:impregnation ratio>activation temperature>pickling times>activation time.(2)Pig bone char was prepared by orthogonal experiment as an additive for anaerobic fermentation of corn straw.The experimental group added pig bone char could promote anaerobic fermentation of corn straw.The peak of methane production was advanced,the average methane concentration was increased,and the cumulative methane production was 68%higher than that of the blank control group.In the anaerobic fermentation experiment,corn straw was used as raw material,sludge was used as inoculum,the fermentation period was 28 days,and the amount of pig bone charcoal was 10%,The results showed that the experimental group with pig bone char could promote the anaerobic fermentation of corn straw.When the preparation conditions of pig bone char were activation temperature 700?,impregnation ratio 2,pickling times twice and activation time 90 min,the daily methane peak value of anaerobic fermentation of corn straw was 4 days earlier than that of the blank control group;The average methane content was 49.97%,which was 25.36%higher than that of the blank control group;the cumulative methane production was 164.54 mL/g VS,which was 68%higher than that of the blank control group.(3)The modified Gompertz equation was used to analyze the kinetics of anaerobic fermentation of corn straw with pig bone char,kinetic analysis showed that the delay period of methane production in the experimental group with pig bone char was shorter than that in the blank control group.The correlation coefficient R2 of fitting is greater than 0.98,and the fitting effect is very good.The lag time of methanogenesis was 3.05?5.42 days in the experimental group and 6.09 days in the blank control group;The delayed period of methanogenesis in the experimental group with pig bone char was 0.67?3.04 days shorter than that in the blank control group.