CO2 CAPTURE BY BIOCHAR FROM MACADAMIA NUT SHELL

Abstract

The rapid development in the plantation area of macadamia trees has led to an
increase in the number of agricultural by-products, most importantly macadamia nut
shells, and may cause environmental concerns if not treated properly. One of the
methods to reduce the negative impact on the environment is to convert it into biochar
by pyrolysis for CO2 adsorption. Pyrolysis of macadamia nut shells was carried out by
Nabertherm at 600oC in an atmosphere containing pure N2. The results of SEM-EDS
analysis and N2 adsorption/desorption isotherms showed that the biochar structure was
highly porous, and the surface area of biochar was 127.44m2/g. The FTIR analysis results
showed that very few functional groups existed on the surface, suggesting that the CO2
adsorption onto this biochar would rather follow a physical capturing mechanism. The
application of biochar for CO2 adsorption was carried out in laboratory conditions of room
temperature and atmospheric pressure, CO2 flow rate of 5 liters /min, and achieved a
high and stable CO2 adsorption value at 1.1mmol/g. This result showed that macadamia
nut shells could be used for the production of cheap and environmentally friendly
absorbent.