Effect of Pyrolysis Temperature on Characteristics of Biochars Derived from Marine Algae Biomass (Ulva Lactuca)

In this study, marine green algae biomass (Ulva lactuca) was used as raw material to obtain biochar, by pyrolysis. Three pyrolysis temperatures were uses (320, 450 and 550 °C), and some important physico-chemical characteristics of the obtained biochars were analyzed. Experimental results show that pyrolysis temperature significantly influences the number and nature of superficial functional groups, as well as the morphology of biochar surfaces. Consequently, biochars derived from marine algae biomass exhibits different biosorption capacities for metal ions from aqueous media. To demonstrate this, Zn(II) ions were selected, and the biosorption capacities obtained for an initial concentration of 160 mg/L increase in the order: 320 °C (17.41 mg/g) < 450 °C (25.22 mg/g) < 550 °C (36.64 mg/g). The results of this study are expected to highlight the most important factors that influence the efficiency of metal ions biosorption and allow the appropriate selection of the pyrolysis temperature.