Sorption treatment of water from chromium using biochar material

Abstract

Sorption treatment of wastewater from chromium compounds is a current and actively developing area of research. However, there is a lack of sorbents combining high efficiency and economic affordability with the possibility of application in industrial conditions. In this work, the sorption properties of biochar material “EcoChar,” obtained as a result of fast pyrolysis of agricultural poultry waste, were studied in relation to the removal of trivalent chromium ions, and the basic thermodynamic parameters of the process, which is the type of strong chemisorption, were determined. Based on the IR spectra of the sorbent material, the formation of chelate complexes by hydrolyzed chromium ions with the involvement of carboxylic groups and simple ether bonds is suggested. Using the Langmuir model, the values of sorption capacity of sorbent were found as, 68.8 ± 0,2 mg Cr(III)/g and 87.5 ± 0,3 mg Cr(III)/g at 298 and 318 K, respectively. These values, which are much higher than those of their corresponding waste material counterparts, make the use of this biochar as an adsorbent advantageous for the removal of Cr(III) containing compounds from acidic wastewater.

Keywords:

• Biochar
• chromium
• «EcoChar»
• equilibrium constant
• Gibbs energy
• wastewater treatment