Abstract
The effectiveness of nanoscale zero-valent iron (nZVI) to remove heavy metals from water is reduced by its low durability, poor mechanical strength, and tendency to form aggregates. A composite of zeolite and nanoscale zero-valent iron (Z-nZVI) overcomes these problems and shows good potential to remove Pb from water. FTIR spectra support nZVI loading onto the zeolite and reduced Fe0 oxidation in the Z-nZVI composite. Scanning electron micrographs show aggregation was eliminated and transmission electron micrographs show well-dispersed nZVI in chain-like structures within the zeolite matrix. The mean surface area of the composite was 80.37m2/g, much greater than zeolite (1.03m2/g) or nZVI (12.25m2/g) alone, as determined by BET-N2 measurement. More than 96% of the Pb(II) was removed from 100mL of solution containing 100mg Pb(II)/L within 140min of mixing with 0.1g Z-nZVI. Tests with solution containing 1000mg Pb(II)/L suggested that the capacity of the Z-nZVI is about 806mg Pb(II)/g. Energy-dispersive X-ray spectroscopy showed the presence of Fe in the composite; X-ray diffraction confirmed formation and immobilization of Fe0 and subsequent sorption and reduction of some of the Pb(II) to Pb0. The low quantity of Pb(II) recovered in water-soluble and Ca(NO3)2-extractable fractions indicate low bioavailability of the Pb(II) removed by the composite. Results support the potential use of the Z-nZVI composite in permeable reactive barriers.
Original language | English (US) |
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Pages (from-to) | 54-60 |
Number of pages | 7 |
Journal | Chemical Engineering Journal |
Volume | 217 |
DOIs | |
State | Published - Feb 1 2013 |
Externally published | Yes |
Keywords
- Composite
- Heavy metals
- Nanoscale
- Zeolite
- Zero-valent iron
ASJC Scopus subject areas
- General Chemistry
- Environmental Chemistry
- General Chemical Engineering
- Industrial and Manufacturing Engineering