Zh. Li et al., Enhanced reduction of chromate and PCE by palletized surfactant-modified zeolite/zerovalent iron, ENV SCI TEC, 33(23), 1999, pp. 4326-4330
Citations number
24
Categorie Soggetti
Environment/Ecology,"Environmental Engineering & Energy
The current research focuses on enhanced removal of chromate and perchloroe
thylene from contaminated water by a combination of a reduction material (r
epresented by zerovalent iron, ZVI) and a sorption material (represented by
surfactant-modified zeolite, SMZ). Natural zeolite and ZVI were homogenize
d and pelletized to maintain favorable hydraulic properties while minimizin
g material segregation due to bulk density differences. The zeolite/ZVI pel
lets were modified with the cationic surfactant hexadecyltrimethylammonium
bromide to increase contaminant sorption and, thus, the contaminant concent
ration on the solid surface. Results of chromate sorption/reduction indicat
e that the chromate sorption capacity of pelletized SMZ/ZVI is at least 1 o
rder of magnitude higher than that of zeolite/ NI pellets. Compared to SMZ
pellets, the chromate removal capacity of SMZ/ZVI pellets in a 24-h period
is about 80% higher, due to the combined effects of sorption by SMZ and red
uction by ZVI. The chromate and PCE degradation rates with and without surf
actant modification were determined separately. The pseudo-first-order redu
ction constant increased by a factor of 3 for PCE and by a factor of 9 for
chromate following surfactant modification. The enhanced contaminant reduct
ion capacity of SMZ/ZVI pellets may lead to a decrease in the amount of mat
erial required to achieve a given level of contaminant removal.