Zero-valent @entity68 (ZVI) as a permeable barrier material for degradation of chlorinated organic compounds has been extensively studied recently. One of the focal areas in ZVI studies is to increase the contaminant reduction rate. In this research, batch tests were performed to evaluate the synergistic effect of sorbed cationic surfactants on degradation of @entity3321 ( @entity11240 ). Sorption of cationic surfactants on ZVI was a function of hydrophobic chain length of the surfactanttail group. Minimal counterion sorption indicated that the sorbed surfactant molecules form a patchy monolayer on ZVI. Both @entity11240 and @entity4965 ( @entity4966 ) degradation by ZVI with and without sorbed surfactant followed pseudo-first-order reaction kinetics. In general, the @entity11240 degradation rate increases as the chain length of sorbed surfactant increases. Compared to unmodified ZVI, both apparent rate constants of @entity11240 degradation and @entity4966 accumulation increased by an order of magnitude when ZVI was modified by @entity69590 . The rate of @entity11240 degradation by ZVI modified to lower surfactant loading was relatively higher than that by ZVI modified to higher surfactant loading. It was speculated that longer chain length will result in better admicelle formations, and thus, promote @entity11240 partition and increase @entity11240 surface concentration or surface admicelle catalysis, while low surfactant loading makes significant amounts of surface reduction sites still available. The @entity11240 reduction rate constants were not affected by solution ionic strength, but high initial solution pH, buffered by @entity1043 and @entity4388 , significantly reduced the @entity11240 degradation rate.

Synergistic effect of cationic surfactants on XXXX degradation by zero-valent @entity68 .

@entity4388 :: ('MESH:D017693', 'Chemical') :: ['sodium bicarbonate'] @entity4966 :: ('CHEBI:16602', 'Chemical') :: ['TCE'] @entity3321 :: ('MESH:D013750', 'Chemical') :: ['perchloroethylene'] @entity11240 :: ('CHEBI:17300', 'Chemical') :: ['PCE'] @entity69590 :: ('CHEBI:39561', 'Chemical') :: ['hexadecyltrimethylammonium'] @entity1043 :: ('MESH:C005686', 'Chemical') :: ['sodium carbonate'] @entity4965 :: ('MESH:D014241', 'Chemical') :: ['trichloroethylene'] @entity68 :: ('MESH:D007501', 'Chemical') :: ['iron']
@entity3321 :: (MESH:D013750,Chemical) :: ['perchloroethylene']
