Synthesis of anion exchange/activated carbon fiber hybrid materials for aqueous adsorption of toxic hexavalent chromium

Zheng, Weihua

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https://hdl.handle.net/2142/29579 Copy

Description

Title

Synthesis of anion exchange/activated carbon fiber hybrid materials for aqueous adsorption of toxic hexavalent chromium

Author(s)

Zheng, Weihua

Issue Date

2012-02-01T00:56:24Z

Director of Research (if dissertation) or Advisor (if thesis)

Economy, James

Department of Study

Materials Science & Engineerng

Discipline

Materials Science & Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Activated Carbon
• anion exchange
• hexavalent chromium
• electrostatic adsorption
• surface reduction
• Point-of-Use application

Abstract

Hexavalent chromium, also known popularly as the “Erin Brockwich chemical”, has recently been identified as a carcinogen by ingestion. Unfortunately, it is present in drinking water supplies in United States. An effective, Point-of-Use (POU) based technology to remove Cr(VI) in tap water is urgently needed to protect human beings against this carcinogen. Due to the inadequate state-of-the-art technology for rapid, selective removal of Cr(VI), a unique hybrid activated carbon/anion exchange system (HACAX) has been developed for the first time in our group. HACAX was synthesized by methylation of PAN based Chemically Activated Carbon Fibers. The HACAX was characterized by BET, SEM, XPS,TGA and elemental analysis. The ion exchange property and adsorption performance towards Cr(VI) were also studied comprehensively. HACAX displays not only very high mesopore content with a surface area up to 1085 m2/g based on coating, but also good strong base ion exchange capacity up to 1.5 meq/gC and exceptionally fast kinetics due to multi-scale facilitated mass transfer. Compared with conventional activated carbon and ion exchange resin systems, HACAX has excellent adsorption capacity towards Cr(VI) even at natural pH and very low concentrations of Cr(VI); besides, HACAX has very fast kinetics and high selectivity which can remove Cr(VI) from 4 ppm down to ppb levels or below; moreover, this hybrid material is also able to convert Cr(VI) to non-toxic Cr(III) to prevent the leaking of Cr(VI). These results showed that HACAX is a unique and effective adsorbent for POU Cr(VI) removal and potentially other anion treatments.

Graduation Semester

2011-12

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http://hdl.handle.net/2142/29579

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Copyright 2011 Weihua Zheng

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