Sorption, kinetics and thermodynamics of phosphate sorption onto soybean stover derived biochar

Rajasekar Karunanithi, Yong Sik Ok, Rajarathnam Dharmarajan, Mahtab Ahmad, Balaji Seshadri, Nanthi Bolan, Ravi Naidu

Research output: Contribution to journalArticlepeer-review

48 Citations (Scopus)


Phosphorus (P) is one of the main sources of eutrophication of water bodies creating ecological problems. Biochar prepared from agricultural waste materials can be used as a potential adsorbent for removing P from waste streams. In the present investigation biochar produced from soybean stover pyrolysed at 700 °C was tested for aqueous P removal in a batch type reactor at different temperatures and solution pHs. The sorption process was evaluated through various isotherms, kinetics models and thermodynamic parameters. It was observed that with an equilibrium time of 24 h, up to 95% of P was removed from water at a temperature of 40 °C at pH 5.5. The sorption experimental data were studied through both Langmuir and Freundlich models and the Langmuir adsorption maximum (Qm) values were 90.90 and 75.75 mg/g at pH 5.5 and 8.5, respectively while the Freundlich equilibrium constant (Kf) values were 4.67 and 4.36 mg/g at pH 5.5 and 8.5, respectively. The rate of adsorption confirmed to follow pseudo-second order kinetics with a better correlation. The thermodynamic parameters predicted that the adsorption process is an endothermic and spontaneous process.

Original languageEnglish
Pages (from-to)113-125
Number of pages13
JournalEnvironmental Technology and Innovation
Publication statusPublished - 2017 Nov
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2017


  • Biochar
  • Kinetics
  • Phosphorus
  • Sorption
  • Thermodynamics

ASJC Scopus subject areas

  • General Environmental Science
  • Soil Science
  • Plant Science


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