Phosphorus speciation and release kinetics of swine manure biochar under various pyrolysis temperatures

Xinqiang Liang, Yi Jin, Miaomiao He, Christophe Niyungeko, Jin Zhang, Chunlong Liu, Guangming Tian, Yuji Arai

Research output: Contribution to journalArticlepeer-review


Converting swine manure to biochar is an effective way to recycle valuable nutrients, but there are few reports on its feasibility as a phosphorus (P) source. The objective of this study was to clarify the unique nature, including P speciation, of manure biochar products under various pyrolysis temperatures. We used solution 31P nuclear magnetic resonance and P K-edge X-ray adsorption near-edge spectroscopy (P XANES) to characterize P species in swine manure biochar. For every 100 °C increment starting from 300 °C, the P content in manure biochar increased by 2.16 to 3.37 g kg−1. However, above 400 °C, organic P species did not appear anymore, and only inorganic P, including orthophosphate and pyrophosphate, existed. P K-edge XANES spectra further showed all biochar samples had higher percentages of Ca3 (PO4)2 and NaP2O7, and lower percentages of FePO4, AlPO4, and inositol hexaphosphate compared to manure. Interestingly, percentages of Ca3(PO4)2, FePO4, and AlPO4 in MB400 (indicating manure pyrolysed at 400 °C) were comparable with those in MB700 while the percentage of NaP2O7 was higher in MB400. Phosphorus release from MB400 maintained a relatively high level at 0.33 g kg−1 during the whole 300-h observation period. These results suggest that with a suitable pyrolysis temperature, it was feasible for manure biochar to be a P source alternative. [Figure not available: see fulltext.].

Original languageEnglish (US)
Pages (from-to)25780-25788
Number of pages9
JournalEnvironmental Science and Pollution Research
Issue number26
StatePublished - Sep 1 2018


  • Biochar
  • K-edge XANE
  • Manure
  • Phosphorus
  • Pyrolysis temperature

ASJC Scopus subject areas

  • Environmental Chemistry
  • Pollution
  • Health, Toxicology and Mutagenesis

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