Preparation Of Caragana Biochar And Its Composting Application

In order to understand the effect of carbonization temperature and moisture content of raw materials on the performance of Caragana biochar,the biochars were prepared by pyrolysis at 300,400,500,and600 ℃ with different water contents(carbonization for 1 h).The charcoal yield,industrial composition,specific surface area,and other basic characteristics of the biochar were analyzed by infrared spectroscopy and elemental analysis.The pore structure of the biochar was also analyzed based on low-temperature nitrogen adsorption.The FHH model calculates the pore fractal dimension,and predicts the Caragana biochar atom cluster model based on the H / C atomic ratio.After screening the Caragana biochar,the carbonization process is selected as follows: carbonization temperature is 600 At ℃,the biochar prepared at a moisture content of 0.23% of Caragana korshinskii was tested for aerobic composting of chicken manure,in order to study the effect of different biochar additions of Caragana korshinskii on the nutrient transformation during the composting process.Chicken manure and wheat straw powder were used as compost raw materials,and caragana biochar with mass fractions of 0%,3%,6%,9%,12% and 15% was added for aerobic composting.,8,19,26,33,and 40 d.The results of pyrolysis carbonization test of Caragana korshinskii showed that under the same moisture content of raw materials,as the carbonization temperature increased,the charcoal yield and volatile matter of Caragana korshinskii gradually decreased,and the ash and fixed carbon gradually increased.At the same carbonization temperature,with the increase of the moisture content of the raw materials,the carbon yield and fixed carbon of Caragana korshinskii charcoal decreased gradually;the ash and volatile matter gradually increased.Regardless of the raw material,the industrial composition tends to be stable when the carbonization temperature is greater than 400 ° C.At a carbonization temperature of600 ℃ and a raw material moisture content of 0.23%,the prepared biochar has the most abundant porosity,with micropores and total pore volumes reaching 0.0649 and 0.1030 cm3 · g-1,respectively;under the same raw material moisture content conditions As the carbonization temperature increased,the relative C content of Caragana biochar increased,and the ratios of H / C,O / C,and(O + N)/ C gradually decreased,indicating the polarity and affinity of Caragana biochar.The water is reduced and the aroma of biochar is enhanced.Therefore,as the carbonization temperature increased,Caragana biochar was more and more stable.Through infrared spectrum analysis of Caragana biochar,it was found that during the carbonization process,the functional groups on the surface of Caragana biochar gradually decreased until it disappeared,forming an aromatic Organic matter based on charcoal.However,when the raw material contains more water,it will reduce the aroma of the biochar,which is not conducive to the condensation reaction of the carbonization process.The biochar prepared at 300 ~ 400 ℃ is mainly mesoporous and macroporous,and its adsorption isotherm The line is similar to the type Ⅱ isotherm and does not have a hysteresis curve.The pore structure is composed of flat slit holes,cracks and tapered holes.The biochar prepared at 500 ~ 600 ℃is mainly a microporous structure,and its adsorption isotherm The line is between type Ⅰ and type Ⅱ,the hysteresis curve is the closest to H4 type;the correlation coefficients of the FHH model fitting curves of Caragana biochar prepared at different carbonization temperatures are close to 1,indicating the pore structure of Caragana biochar It has good fractal characteristics.At the same time,the fractal dimension D of Caragana biochar prepared under different carbonization temperatures satisfies 2≤D≤3,which can well characterize the complexity and heterogeneity of the pore structure.The research results can provide a theoretical basis for the resource utilization of Caragana korshinskii and the popularization and application of Caragana korshinskii in agricultural production and ecological restoration.Based on the H / C atom ratio study of the molecular size of aromatic clusters in Caragana biochar,it was found that as the carbonization temperature increased,Caragana biochar gradually thickened and circulated and aromatized,thereby quantitatively expressing Caragana biochar.Carbon thick cyclization,aromatization degree.The aerobic composting test results in chicken manure showed that compared with the control group CK,the addition of Caragana biochar can shorten the compost heating period by 1 ~ 2 d,extend the staying period of the compost high temperature period by 2 ~ 4 d,and increase the water retention capacity of the compost.;And it is conducive to the adsorption of ammonia during high temperature composting,reducing nitrogen loss and improving compost quality.After the composting was completed,the addition of Caragana biochar could increase the total nitrogen mass fraction by 5.59% to 27.38%.Regardless of whether or not biochar was added,the total phosphorus and total potassium in each treatment increased rapidly with the composting process.Adding Caragana biochar to chicken manure and wheat straw compost can accelerate the composting process and reduce the volatilization loss of ammonia.Caragana biochar is an effective composting additive,and the suitable addition ratio of Caragana biochar is between9% and 12%.