Benzene and MTBE removal by Fenton’s process using stabilized Nano Zero-Valent Iron particles

A bench-scale study was designed for removal of Methyl Tertio Butyl Ether (MTBE) and benzene from south of Tehran groundwater. The experiments were implemented on a one-dimensional soil column with similar chemical and physical conditions of the region. Fenton’s chemical oxidation with stabilized nano zero-valent iron particles (S-NZVI) as catalyst was used. For treatment of groundwater polluted with 2 mg L-1 MTBE and 1 mg L-1 benzene, optimum concentrations of H2O2 and S-NZVI were 1500 and 300 mg L-1, respectively. The optimum concentrations led to 78 % elimination of MTBE and 87 % of benzene. Hazardous by-products (acetone and tertio-butyl alcohol) concentrations were less than 0.1 mg L-1, which were considered to be negligible. The soil permeability was reduced to 30 % after removal process. To increase the system efficiency and reduce the consumption of iron, the reaction environment was acidified down to pH = 3.2 led to removal efficiency of 90 % and 96 % for MTBE and benzene, respectively. The scavengers (ions) reduced the system efficiency up to 15 %. This study indicates that theoretically the MTBE and benzene could be removed from groundwater using Fenton’s chemical oxidation with S-NZVI

Wet deposition of hydrocarbons in the city of Tehran-Iran

Air pollution in the city of Tehran has been a major problem for the past three decades. The direct effects of hydrocarbon contaminants in the air are particularly important such as their carcinogenic, mutagenic, and teratogenic effects which can be transported to other environments via dry and wet deposition. In the present study, rainwater samples were collected and analyzed for 16 polycyclic aromatic hydrocarbons (PAHs), benzene, toluene, ethyl benzene, and xylene (BTEX) as well as fuel fingerprints in two ranges of gasoline (C5–C11) and diesel fuel (C12–C20) using a gas chromatograph equipped with a flame ionization detector (GC/FID). Mean concentrations of ∑16 PAHs varied between 372 and 527 µg/L and for BTEX was between 87 and 188 µg/L with maximum of 36 µg/L for toluene. Both gasoline range hydrocarbons (GRH) and diesel range hydrocarbons (DRH) were also present in the collected rainwater at concentrations of 190 and 950 µg/L, respectively. Hydrocarbon transports from air to soil were determined in this wet deposition. Average hydrocarbon transportation for ∑PAHs, BTEX, GRH, and DRH was 2,747, 627, 1,152, and 5,733 µg/m2, respectively

Evaluation of Chlorinated Hydrocarbon Concentrations in Tehran’s Districts Drinking Water

In this study Tehran’s drinking water was evaluated for the presence of chlorinated hydrocarbons during spring and summer of 2009. Chlorinated hydrocarbons are an important class of environmental pollutants that cause adverse health effects on human’s kidney, liver and central nervous systems. In this study six water districts were selected for taking drinking water samples in the city of Tehran as well as one location outside the city limits. The samples were analyzed by GC/MS using EPA method 8260. The average concentrations of 1,1-dichloroethylene, 1,2 Dichloromethane, Tetra chloromethane, Trichloroethylene and tetra chloroethylene were determined during a 7 month period and the results were 0.04ppb, 0.52ppb, 0.01ppb, 0.24ppb, 0.03ppb respectively. The highest concentration of chlorinated hydrocarbon observed in Tehran’s drinking water was Trichloroethylene and the lowest concentration was Tetra chloromethane. Districts 5 and 6 showed the highest concentrations of chlorinated hydrocarbons in the city of Tehran