Jb. Brower et al., COMPARISON OF ION-EXCHANGE RESINS AND BIOSORBENTS FOR THE REMOVAL OF HEAVY-METALS FROM PLATING FACTORY WASTE-WATER, Environmental science & technology, 31(10), 1997, pp. 2910-2914
The NCP (Neurospora crassa gene expressed in the periplasmic space) is
a recombinant Escherichia coli expressing the Neurospora crassa metal
lothionein gene within the periplasmic space. The, NCP has been shown
to remove heavy metals from solutions containing low concentration of
heavy metals. In this study, the ability of NCP to remove heavy metals
from wastewater was compared to the commercial sorbents Duolite GT-73
, IRC-718, and BIG-FIX. Three process wastewater streams, acid/alkali,
chromate, and cyanide, were tested at their original pH and near neut
ral pH. In addition to other contaminants, the wastewaters contained m
etals including Cd, Cu, Ni, and Ag. NCP was most efficient in removing
the heavy metals from wastewaters at near neutral pH. Chromium remova
l per gram of IRC-718 at pH 2.05 was an order of magnitude higher than
any other sorbent in either pH-unadjusted or pH-adjusted samples. Duo
lite GT-73, IRC-718, and BIG-FIX had similar efficiency in removing he
avy metals from the pH-adjusted wastewater. When the sorbents were tes
ted for removal of part per billion levels of Cd-109, NCP demonstrated
the highest percent removal. These results suggest potential treatmen
t strategies for metal-contaminated wastewaters involving pH adjustmen
t and primary treatment with a commercial sorbent followed by polishin
g with NCP.