Details

Autor(en) / Beteiligte

• Godinho, D.
• Dias, D.
• Bernardo, M.
• Lapa, N.
• Fonseca, I.
• Lopes, H.
• Pinto, F.

Titel

Adding value to gasification and co-pyrolysis chars as removal agents of Cr3

Ist Teil von

• Journal of hazardous materials, 2017-01, Vol.321, p.173-182

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2017

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• [Display omitted] •Rice wastes and their blends are valorised through pyrolysis and gasification.•Chars are fully characterised and used in the removal of Cr3+ from liquid medium.•The gasification char presents a high performance on the removal of Cr3+.•The chars, namely from gasification, get a high added-value for the Cr3+ recovery. The present work aims to assess the efficiency of chars, obtained from the gasification and co-pyrolysis of rice wastes, as adsorbents of Cr3+ from aqueous solution. GC and PC chars, produced in the gasification and co-pyrolysis, respectively, of rice husk and polyethylene were studied. Cr3+ removal assays were optimised for the initial pH value, adsorbent mass, contact time and Cr3+ initial concentration. GC showed a better performance than PC with about 100% Cr3+ removal, due to the pH increase that caused Cr precipitation. Under pH conditions in which the adsorption prevailed (pH<5.5), GC presented the highest uptake capacity (21.1mg Cr3+ g−1 char) for the following initial conditions: 50mg Cr3+ L−1; pH 5; contact time: 24h;L/S ratio: 1000mLg−1. The pseudo-second order kinetic model showed the best adjustment to GC experimental data. Both the first and second order kinetic models fitted well to PC experimental data. The ion exchange was the dominant phenomenon on the Cr3+ adsorption by GC sample. Also, this char significantly reduced the ecotoxicity of Cr3+ solutions for the bacterium Vibrio fischeri. GC char proved to be an efficient material to remove Cr3+ from aqueous solution, without the need for further activation.