Heliyon (Sep 2023)

Phosphorus adsorption using chemical and metal chloride activated biochars: Isotherms, kinetics and mechanism study

  • Bijoy Biswas,
  • Tawsif Rahman,
  • Manish Sakhakarmy,
  • Hossein Jahromi,
  • Mohamed Eisa,
  • Jonas Baltrusaitis,
  • Jasmeet Lamba,
  • Allen Torbert,
  • Sushil Adhikari

Journal volume & issue
Vol. 9, no. 9
p. e19830

Abstract

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Efficient treatment of nutrient-rich wastewater is of paramount importance for protecting the ecosystem. In this work, an efficient, abundant, and eco-friendly adsorbent was derived from biochar and employed for phosphorus (P) adsorption. The key factors influencing the P removal efficiency of the activated biochar, including P concentration, pH, dosage, temperature, adsorption time, and influence of co-existing ion type, were investigated. Maximum P adsorption percentage (100%) was obtained with 10 mg/L and zinc chloride activated biochar (BC–Zn) compared to the other activated biochars. Results show that by increasing the P concentration from 5 to 200 mg/L, the phosphorus adsorption capacity increases from 0.13 to 10.4 mg/g biochar. Isotherms and kinetic studies further show that the P adsorption follows the Langmuir and quasi-second-order kinetic models. The mechanistic investigation demonstrated that P adsorption occurred by precipitation reaction. Furthermore, P desorption has been studied at different time intervals to understand the P release rate after adsorption.

Keywords