Microwave treatment of naphthenic acids in water.
Naphthenic acids (NAs) are natural constituents of bitumen and crude oil. These compounds are concentrated as part of the oil sands process water (OSPW) during petroleum refining and separation from oil sands. NAs are considered among the major water contaminants in OSPW due to their toxicity and environmental recalcitrance. A laboratory scale microwave system was developed and experiments were conducted to determine the efficiency of NA degradation during microwave treatment. The effects of water source and quality (deionized lab water and river water) and of TiO(2) catalyst in the degradation process were also investigated. Degradation kinetic parameters for both total NAs and individual z-family were calculated. The microwave system degraded OSPW NAs and commercial Fluka NAs in river water in the presence of TiO(2) rapidly, producing half-life values of 3.32 and 3.61 hours, respectively. Toxicity assessments of the NA samples pre-and post-treatment indicated that the microwave system reduced overall toxicity of water containing Fluka NAs from high (5 min. IC(50) v/v = 15.85%) to moderate (5 min. IC(50) v/v = 36.45%) toxicity levels. However, a slight increase in toxicity was noted post-treatment in OSPW NAs.
Mishra
Sabyasachi
S
College of Agricultural Engineering & Post Harvest Technology, Central Agricultural University, Gangtok, Sikkim, India.
Meda
Venkatesh
V
Dalai
Ajay K
AK
Headley
John V
JV
Peru
Kerry M
KM
McMartin
Dena W
DW
D002264:Carboxylic Acids / Q000737:chemistry / Q000302:isolation & purification* / Q000633:toxicity; D002384:Catalysis; D006207:Half-Life; D007220:Industrial Waste; D007700:Kinetics; D008872:Microwaves; D010578:Petroleum; D014025:Titanium / Q000737:chemistry; D014867:Water / Q000737:chemistry*; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*
D002264:Carboxylic Acids; D007220:Industrial Waste; D010578:Petroleum; D014867:Water; C009495:titanium dioxide; D014025:Titanium; C046170:naphthenic acid