A circular economy approach for phosphorus removal using algae biochar
Journal Publication ResearchOnline@JCUAbstract
In this study, a potential circular economy approach for macroalgae (Ulva ohnoi) was investigated considering the crucial stages of biorefinery. Important stages, such as drying of biomass, production of biochar (pyrolysis), and application of biochar for phosphorus removal were studied and reported. It is important to note that drying macroalgae biomass from an average wet basis moisture content of ca. 70–85% to a moisture content suitable for thermal conversion, ca. 10%, is a challenging task. The physicochemical properties of biomass as well as biochar were characterized and were correlated with their capacity to adsorb phosphorus (P). The initial thermal analysis of macroalgae biomass revealed that the major weight loss occurred between 150 and 550 °C. The kinetics of the pyrolysis process indicate the requirement of higher apparent activation energy in between 232 and 836 kJ mol−1. An increase in the pore diameter, surface area, and pore volume in the biochar was noticed when the temperature of the pyrolysis process was increased. The highest P adsorption (78 mg-P/ g biochar) during the batch experiments was noticed with biochar obtained at 700 °C and can be due to the availability of alkali and alkaline earth metals. The kinetic study for P adsorption was described well by a pseudo second-order model. Biochar produced from macroalgae biomass can be considered as environmentally beneficial and low-cost adsorbent for phosphorus recovery. The biochar after adsorption may be used in agriculture as a slow release fertiliser due to significant amount of brushite.
Journal
Cleaner and Circular Bioeconomy
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1
ISBN/ISSN
2772-8013
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Pages Count
9
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Publisher
Elsevier
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DOI
10.1016/j.clcb.2022.100005