Document Type : Research Paper
Department of Soil Science,Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
Department of Biosystem Engineering, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
Biochar is a recalcitrant substance that is produced through the pyrolysis process. This study was accomplished in Ahvaz city, located in the central part of Khuzestan Province. To produce biochar, the biomass of Prosopis farcta pyrolyzed with a temperature of 400°C to 800°C using the heating rate of 3 to 7 °C/min. Afterward, the electrical conductivity, cation exchange capacity, pH, specific surface area, and organic carbon of biochar were recorded by employing the standard methods. The optimization of pyrolysis factors such as temperature and heating rate is accomplished by using the Response Surface technique. Based on the results obtained, the temperature of the process was the most effective variable on the biochar characteristics. Besides, the temperature has a more substantial effect on biochar´s structure than the heating rate. Also, the modeling results indicate that with enhancing the pyrolysis temperature, both of the EC/pH of produced biochar enhanced mainly due to the concentration effect and reduction of acidic functional groups. With strengthening the pyrolysis temperature and heating rate, organic carbon and the specific surface area of biochar enhanced while the cation exchange capacity decreased. According to the obtained results, the best model was found to be a quadratic model. In addition, the model for EC parameter with the P-value of 0.0004 had the lowest effect in comparison with other studied pyrolysis factors. In general, the conditions of the pyrolysis process have a remarkable impact on the biochar characteristics; therefore, determine the effectiveness of biochar as an organic amendment. To the best of the author's knowledge, the present work is the first report assessing the effect of heating rate/ temperature on the biochar characteristics produced from Prosopis farcta in the world.