A green biochar/iron oxide composite for methylene blue removal

Ping Zhang, David O'Connor, Yinan Wang, Lin Jiang, Tianxiang Xia, Liuwei Wang, Daniel C.W. Tsang, Yong Sik Ok, Deyi Hou

Research output: Journal article publicationJournal articleAcademic researchpeer-review

353 Citations (Scopus)


Adsorbents that effectively remove dye substances from industrial effluents are needed for the protection of human health and the natural environment. However, adsorbent manufacture is associated with secondary environmental impacts. In this study, a green biochar/iron oxide composite was produced using a facile approach involving banana peel extract and FeSO4. The modified biochar's capacity to adsorb methylene blue (MB) was considerably enhanced (Langmuir Qmax of 862 mg/g for MB when C0 = 500 mg/L, pH = 6.1, T =313 K) compared to the unmodified banana peel biochar, and exhibited good performance for a wide range of pH values (pH 2.05–9.21). The Langmuir isotherm model and pseudo second-order kinetic model accurately describe the adsorption process. The material properties and corresponding adsorption mechanisms were investigated by various experimental techniques. Enhanced MB adsorption by the biochar/iron oxide composite is attributed to increased electronic attraction to MB molecules, as evidenced by XPS analysis. High adsorption capacity was retained after 5 regeneration cycles. This study suggests that biochar can be modified by a green synthesis approach to produce biochar/iron oxide composite with good MB removal capacity.

Original languageEnglish
Article number121286
JournalJournal of Hazardous Materials
Publication statusPublished - 15 Feb 2020


  • Dye adsorption
  • Engineered biochar
  • Green synthesis
  • Methylene blue
  • Modified biochar

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis


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