Influence of different pyrolysis temperature on the characteristics of forestry waste biochar for sodium adsorption.

Soil salinization is a major problem affecting agriculture globally. One approach to restore saline soil is through the application of biochar which is great at adsorbing salt ions and thus amending salt-affected soils. Biochar produced using forestry wastes (Gigantochloa levis and Melaleuca cajuputi) were pyrolyzed at 300, 450 and 600 ℃ for 2 h. Proximate and ultimate analyses were done followed with physical and chemical analyses of the biochar and their raw materials before undergoing the sodium adsorption study. The fixed carbon was observed to increase from 9.636 to 72.919% (G. levis) and 9.473–69.950% (M. cajuputi) upon carbonization of the raw materials. These values correlated with the increasing C content of the samples, which also resulted in lower H/C value especially for G-600 and M-600 samples. It was found that biochar aromaticity and stability increased with increasing temperature. In addition, field emission scanning electron microscopy (FESEM) elucidated that higher pyrolysis temperature increased the porosity and surface area. The pH observed to increase from 5.36 to 7.97 (G. levis) and 4.19–9.05 (M. cajuputi) following higher pyrolysis temperature. From the analyses conducted, the biochar produced was identified to have a potential for sodium adsorption. [ABSTRACT FROM AUTHOR]