Preparation of activated carbons from wood waste including northern hardwood pins-fines and wood dust was conducted and then compared through the following methods: physical pyrolysis and CO2 activation, vacuum pyrolysis and CO2 activation, CO2 gasification, and vacuum CO2 gasification processes. Experimental results show that chars and activated carbons with high surface area and pore volume are produced from wood waste through a vacuum CO2 pyrolysis/gasification process. The effects of operation variables of vacuum pyrolysis/gasification on the properties of chars and activated carbons were investigated to identify and optimize the temperature, heating time, and heating rate. The optimized vacuum CO2 gasification conditions were found to be a temperature of 800 °C, a heating rate of 20 °C/min, and a holding time of 2 h respectively. The prepared wood-chars and activated carbons were characterized by nitrogen physisorption, scanning electron microscopy (SEM). Fourier transform infrared (FTIR) spectra determined any changes in the surface functional groups produced during different preparation stages.

    Abstract 
    Graphic abstract
    1 Introduction
    2 Materials and methods
        2.1 Materials
        2.2 Preparation of charsactivated carbon
        2.3 Characterization of the prepared activated carbons
    3 Results and discussion
        3.1 Thermogravimetric analysis (TGA)
        3.2 Fourier transform infrared spectroscopy (FTIR)
        3.3 Main gaseous products during different thermal treatment processes
        3.4 Yield of chars and activated carbons
        3.5 Effects of process conditions on AC yield, surface area and micropore structures
        3.6 Morphologies of char and AC samples
    4 Conclusions
    Acknowledgements 
    References

• Qiangu Yan(Ligwood LLC, Madison)
• Jinghao Li(Forest Products Laboratory, USDA Forest Service, One Gifford Pinchot Drive)
• Zhiyong Cai(Forest Products Laboratory, USDA Forest Service, One Gifford Pinchot Drive)