Adsorption of Cr(VI) from aqueous solutions by HNO3-purified and chemically activated pyrolytic tire char

作者：Makrigianni Vassiliki; Giannakas Aris; Bairamis Feidias; Papadaki Maria; Konstaninou Ioannis

来源：Journal of Dispersion Science and Technology, 2017, 38(7): 992-1002.

DOI：10.1080/01932691.2016.1216862

• Acid treatment
• activation
• Cr(VI)
• pyrolytic char
• tires

Pyrolytic tire char adsorbents either demineralized by nitric acid (purified char, PC) or activated with KOH-calcination (activated char, AC) were used for Cr(VI) removal from aquatic solutions and studied by adsorption kinetics, isotherms, and thermodynamics. Adsorbent's physicochemical characteristics were studied by several techniques such as X-ray diffraction, porosimetry, scanning electron microscopy, elemental analysis, and Boehm titration. For PC, acid treatment leads partially to a mesoporous structure while for AC, KOH activation creates also a microporosity enhancing the specific surface area at 443m(2)g(-1). Cr(VI) adsorption onto both adsorbents followed better second-order kinetics and Langmuir isotherm models and it was exothermic (H<0) and spontaneous (G<0). The maximum Cr(VI) adsorption capacity for AC and PC was 114 and 79.47mgg(-1), respectively, at pH=4. The present work reveals that AC and PC can be efficient sorbents for the removal of heavy metal ions, contributing both positively to wastewater treatment and waste tire pyrolysis plants.
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• 出版日期2017