Environmental Technology & Innovation 19 (2020) 100808 Contents lists available at ScienceDirect Environmental Technology & Innovation journal homepage: www.elsevier.com/locate/eti Nonlinear sorption of phosphorus onto plant biomass-derived biochars at different pyrolysis temperatures Joseph Osafo Eduah a,b , Stephan Weck Henriksen b , Eric Kwesi Nartey a,∗ , Mark Kofi Abekoe a , Mathias Neumann Andersen c a Department of Soil Science, School of Agriculture, University of Ghana, P. O. Box LG 245, Legon, Ghana b Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350, Copenhagen, Denmark c Department of Agroecology and Environment, Aarhus University, Denmark article info Article history: Received 29 January 2020 Received in revised form 24 March 2020 Accepted 12 April 2020 Available online 18 April 2020 Keywords: Feedstock Biochar Pyrolysis temperature Sorption Phosphorus abstract Aside the characterization of feedstocks and biochars (BCs), the nonlinear sorption of phosphorus (P) onto corn cob (CC), rice husk (RH), cocoa pod husk (CP) and palm kernel shell (PK) BCs charred at 300, 450 and 650 ◦ C were investigated using series of batch experiments. Conversion of feedstock to BC resulted in a higher pH, C content, ash, fixed C, surface area (SA) and lower volatile matter, moisture, H, N, O and S contents. Increasing pyrolysis temperature proportionally decreased the polarity (O/C, O+N/C, and O+ N+ S/C), volatile matter, moisture content, readily labile organic C and potentially unstable C vis-à-vis an increased in C content, fixed C, stable C and aromaticity (H/C). The nonlinearity index (n) as well as P sorption capacity (K F ) increased with temperature and were highly dependent on BC properties. Significant linear relationships were observed between P sorption parameters (n and K F ) and O content, polarity, aromaticity, fixed C, stable C, readily labile organic C and SA. The low polarity and high aromaticity and SA resulted in the high nonlinear sorption of P at 650 ◦ C. Findings of this study provides insight into P sorption behaviour, thereby serving as a theoretical basis for biochar application either agronomically or environmentally. © 2020 Published by Elsevier B.V. 1. Introduction The release of carbon dioxide as a major greenhouse gas is considered a key negative effect associated with the burning of agricultural wastes by anthropogenic activities (Lehmann, 2007). Such occurrence is avoided through carbonization of agricultural wastes, producing biochar (BC) (Lehmann, 2007; Beesley et al., 2011). Biochar is the product of thermochemi- cal combustion of biomass (e.g. corn cob, cocoa pod and palm kernel shell) in limited or no oxygen environment (Lehmann et al., 2006). Biochar has received increasing interest as an approach to addressing the challenges of global climate change and also ensuring sustainable agricultural development (Lehmann et al., 2006; Subedi et al., 2016). Previous studies have shown that Biochar stores carbon (C) in soils for hundreds to thousands of years, potentially reducing greenhouse gas levels (Lehmann, 2007; Beesley et al., 2011). Aside carbon sequestration, the multi-functionality of BC is also related to improving soil fertility, wastewater treatment and metal immobilization (Uchimiya et al., 2010; Awad et al., 2012; Chen et al., 2011; Eduah et al., 2019). The interaction of BC with tropical and temperate soils is reported to improve soil ∗ Corresponding author. E-mail address: enartey@ug.edu.gh (E.K. Nartey). https://doi.org/10.1016/j.eti.2020.100808 2352-1864/© 2020 Published by Elsevier B.V.