Thermal treatment of poultry litter: Part I. Characterization by immediate analysis and gravimetric yield

Abstract

Producing biochar from poultry litter through slow pyrolysis is a farm-based, value added approach to recycle organic residues. Experiments were conducted to examine how heat treatments affected the final composition of carbonized and pyrolyzed material in relation to immediate analysis and gravimetric yield to assess agronomic performance value. These processes were carried out in porcelain containers containing samples of poultry litter and placed in a muffle furnace. The treatments corresponded to three temperatures: samples carbonized at 250 °C (CPL) and pyrolyzed at 350 and 450 °C (PPL). Samples were analyzed in relation to the volatile content, fixed carbon, ash, moisture, pH, electrical conductivity (EC), and zero charge point (ZCP). The PPL350 and PPL450 biochars had the highest ash contents and the lowest fixed carbon, moisture and gravimetric yields. The increase in temperatures used in the process resulted in higher pH and electrical conductivity values. In addition, the ZCP value, with the exception of CPL250, showed the presence of negative charges on the surface of the biochars.

Thermal treatment of poultry litter: Part II. Evaluation of structural and morphological characteristics

“…The pyrolysis of the raw material leads to a loss of mass in the form of volatile compounds that include the loss of hemicellulose, cellulose, and lignin, forming compounds with high carbon content, as can be seen in Part I of this paper (Fernandes et al, 2022). With the loss of these compounds, macro-, meso-, and micropores are formed, which increase the specific surface area of the biochar.…”

“…The raw material used to produce the biochar was broiler poultry litter collected at the State University of Paraíba experimental farm, in the municipality of Lagoa Seca (07º 09' 22.42" S; 35º 52' 09.64'' W). The preparation of the raw material and the thermal process used in this work with three temperatures of thermal degradation, 250, 350 and 450 °C, in triplicate, following a heating rate of 10 °C min -1 , as well as the carbonization procedure, were published in Part I of this research (Fernandes et al, 2022). CPL250 (poultry litter carbonized at 250 °C), PPL350, and PPL450 (poultry litter pyrolyzed at 350 and 450 °C, respectively), were analyzed by SEM, EDS, N 2 adsorption-desorption isotherms (surface area, pore volume, and diameter), and FTIR.…”