Towards biochar and hydrochar engineering-influence of process conditions on surface physical and chemical properties, thermal stability, nutrient availability, toxicity and wettability

Diéguez Alonso, Alba
Funke, Axel
Anca-Couce, Andrés
Rombolà, Alessandro Girolamo
Ojeda Castro, Franklin Gerardo
Bachmann, Jörg
Behrendt, Frank

Open PDF

Open link

Publication date

January 2018

DOI

10.3390/en11030496

Publisher

MDPI AG

Abstract

The impact of conversion process parameters in pyrolysis (maximum temperature, inert gas flow rate) and hydrothermal carbonization (maximum temperature, residence time and post-washing) on biochar and hydrochar properties is investigated. Pine wood (PW) and corn digestate (CD), with low and high inorganic species content respectively, are used as feedstock. CD biochars show lower H/C ratios, thermal recalcitrance and total specific surface area than PW biochars, but higher mesoporosity. CD and PW biochars present higher naphthalene and phenanthrene contents, respectively, which may indicate different reaction pathways. High temperatures (>500 °C) lead to lower PAH (polycyclic aromatic hydrocarbons) content (<12 mg/kg) and higher specific su...