Tomato waste biochar in the framework of circular economy

Tomato pomace was slowly pyrolyzed at 350 and 550 degrees C (under an N-2 flow of 50 L/h) at a rate of 6 degrees C/min and a res-idence time of 1:30 h to produce two biochars named B350 and B550, respectively. In addition, the two biochars were chemically activated with Kappa Omicron Eta (at a ratio of 1:10 w/v) at 800 degrees C to produce two new materials named BA350 and BA550. The four biochars produced were characterized physically and chemically (pH, yield, calorific value). They were also analyzed by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (B.E.T), elemental analysis (EA), and thermogravimetric analysis (TGA). The results showed that as the pyrolysis temperature increased (350 to 550 degrees C), the specific surface area (SSA) increased. The latter was also significantly increased by the activation process. EA showed a variation in the mineral content of the produced biochars, resulting in a different content of the biochars after activation. The parameters studied showed that biochars from tomato waste could be used as an organic amend-ment to improve soil fertility in agricultural. In addition, because of their ability to absorb water, they could be used as a water reservoir in soils in arid areas.