Photocatalytic degradation of propanil and molinate over TiO2 suspensions

2002 ◽  
Vol 2 (5-6) ◽  
pp. 225-232 ◽  
Author(s):  
T.A. Albanis ◽  
I.K. Konstantinou ◽  
V.A. Sakkas

The light-induced degradation of propanil and molinate under simulated solar irradiation has been investigated in aqueous solutions containing TiO2 suspensions as photocatalysts. The study focuses on the identification of possible intermediate products and the determination of inorganic ions formed during the process, using several powerful analytical techniques such as gas chromatography mass-spectrometry (GC-MS) and ion chromatography (IC). The primary degradation of propanil and molinate has been a fast process with half-lives varying from 4.3 to 2.9 minutes respectively, and followed pseudo-first-order kinetics according to the Langmuir-Hinshelwood model. The stoichiometric transformation of organic chlorine into chloride ion and organic sulfur to sulfate ions was observed for propanil and molinate respectively, whereas oxidation of nitrogen to nitrate ions took place at delayed irradiation times for both herbicides. The mineralization of the organic carbon to CO2 after 240 min of irradiation was found to be ≥ 95% for both herbicides. Various organic intermediates detected during the treatment have been identified by GC/MS techniques. Based on this by-product identification, a possible multi-step degradation scheme was proposed for each herbicide including hydroxylation, dechlorination, dealkylation and oxidation steps that lead to the mineralization of the starting molecule.

2013 ◽  
Vol 781-784 ◽  
pp. 2129-2132 ◽  
Author(s):  
Yan Wen Gong ◽  
Xue Ni Cheng ◽  
Hong Xun Zhang

Nitrogen doping TiO2was prepared and used to degrade acrolein wastewater under simulated solar irradiation acrylic acid. The results showed that the removal of acrolein, hydroquinone and acrylic acid were 0.73, 0.64, 0.26 after 4 hour degradation by TiO2/UV system. The degradation of acrolein, hydroquinone and acrylic acid using TiO2/UV system followed pseudo first-order kinetics. It results indicated that this proposed method can be useful for the pretreatment acrolein wastewater.


2019 ◽  
Vol 85 (7) ◽  
pp. 16-21
Author(s):  
Liliya R. Mubarakova ◽  
German K. Budnikov

Sultones are cyclic esters of hydroxysulfonic acids, which are formed in the process of sulfonation of α-olefins with sulfur trioxide gas. More stable sultones may be present in the final product — an anionic surfactant — sodium α-olefin sulfonate (AOC-Na). AOC-Na is widely used in the production of household chemicals and cosmetic products, including liquid dishwashing detergents. Sultones are strong skin sensitizers, their level in AOC-Na should be strictly controlled and not exceed 5 ppm. Operational and strict control of the sultone content upon AOC-Na production allows timely adjustment at the stage of hydrolysis, which leads to a more complete disclosure of the sultone cycle with the formation of the corresponding olefin sulfonates and hydroxyalkanesulfonates. We propose a method for determining δ-hexadecansultone in liquid dishwashing detergents and sodium α-olefinsulfonates obtained on the basis of α-olefins of C14 – C16 fractions using GC/MS, which provides shortening of sample preparation and keeps the sensitivity with a detection limit of 0.02 mg/kg. The effect of various weakly polar and non-polar organic solvents used for Sultone extraction from AOC-Na and liquid detergent on liquid extraction based on the dispersion of the extractant in an alcohol/water phase is studied. When selecting the solvent we have shown that the use of diethyl ether provided the best extraction of the analyte. Determination of the analyte extraction recovery was performed using the reaction of hydrolysis of the extracted mixture. We specified the operating mode of the device which provided complete separation of the components of the analyzed compounds including the samples of liquid detergent for dishes being a multicomponent mixture of complex composition.


2011 ◽  
Vol 3 (1) ◽  
Author(s):  
Lies Indah Sutiknowati

There is an information how to identify hydrocarbon degrading bacteria for bioremediation of marine oil spill. We have Bioremediation treatment for degradation of oil spill on Pari island and need two kind of experiment there are tanks experiment (sampling 0 to 90 days) and semi enclosed system (sampling 0 to 150 days). Biostimulation with nutrients (N and P) was done to analyze biodegradation of hydrocarbon compounds. Experiment design using fertilizer Super IB and Linstar will stimulate bacteria can degrade oil, n-alkane, and alkane as poly aromatic hydrocarbon. The bacteria communities were monitored and analyzed by Denaturing Gradient Gel Electrophoresis (DGGE) and Clone Library; oil chemistry was analyzed by Gas Chromatography Mass Spectrometry (GCMS). DNA (deoxyribonucleic acid) was extracted from colonies of bacteria and sequence determination of the 16S rDNA was amplified by primers U515f and U1492r. Strains had been sequence and had similarity about 90-99% to their closest taxa by homology Blast search and few of them suspected as new species. The results showed that fertilizers gave a significant effect on alkane, PAH and oil degradation in tanks experiment but not in the field test. Dominant of the specific bacteria on this experiment were Alcanivorax, Marinobacter and Prosthecochloris. Keywords: Bioremediation, Biostimulation, DGGE, PAH, Pari Island


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