Production Factors Controlling the Physical Characteristics of Biochar Derived from Phytoremediation Willow for Agricultural Applications

Ashleigh J. Fletcher, Malcolm A. Smith, Andreas Heinemeyer, Richard Lord, Christopher J. Ennis, Edward Matthew Hodgson, Kerrie Farrar

Research output: Contribution to journalArticlepeer-review

31 Citations (SciVal)
15 Downloads (Pure)


Willow, a leading bioenergy feedstock, may be planted for bioremediation and has been used, more recently, as the biomass feedstock in the manufacture of biochar for agricultural applications. Here, we present a detailed study of the physical and chemical factors affecting willow char properties, where the feedstock is a by-product of bioremediation, potentially transferring pollutants such as heavy metals to the wood feed. Biochar samples were produced via pyrolysis of short-rotation coppice willow, grown on contaminated land, using several treatment times at heat treatment temperatures (HTTs) in the range 350–650 °C, under a constant flow of argon, set at either 100 or 500 mL min−1. The samples were analysed for yield, elemental analysis and structural characteristics, including surface area and pore size distribution, surface functionality and metal content. All chars obtained have high fixed carbon contents but vary in surface characteristics with a marked increase in basic character with increasing HTT, ascribed to the removal of surface oxygen moieties. Results indicate a minimum pyrolysis temperature of 450 °C is required to produce a defined mesoporous structure, as required to facilitate oxygen transport, HTT ≥ 550 °C produces total surface area of >170 m2 g−1 and, more importantly, an appreciable external surface area suitable for microbial colonisation. The data show that selection and optimisation of char properties is possible; however, the interplay of factors may mean some compromise is required.
Original languageEnglish
Pages (from-to)371-380
Number of pages10
JournalBioenergy Research
Issue number1
Early online date29 Sept 2013
Publication statusPublished - 01 Mar 2014


  • Biomass
  • Carbon sequestration
  • Energy crop
  • Heavy metals
  • Pyrolysis
  • Surface texture


Dive into the research topics of 'Production Factors Controlling the Physical Characteristics of Biochar Derived from Phytoremediation Willow for Agricultural Applications'. Together they form a unique fingerprint.

Cite this