Due to the low water solubility of polybromi- nated diphenyl ethers, organic solvent is usually added into the oxidation system to enhance the removal efficiency. In this study the photocatalytic degradation of decabr...Due to the low water solubility of polybromi- nated diphenyl ethers, organic solvent is usually added into the oxidation system to enhance the removal efficiency. In this study the photocatalytic degradation of decabromodi- phenyl ether （BDE209）, a type ofpolybrominated diphenyl ether used throughout the world, in pure water without the addition of organic solvent was investigated. In the pure water system, BDE209 was not dissolved but dispersed as nano-scale particles with a mean diameter of 166 nm. Most of BDE209 （〉 98%） were removed within 4 h and the final debromination ratio was greater than 80%. Although the addition of organic solvent （tetrahydrofuran, THF） could lead to a relatively high BDE209 degradation rate, the final debromination ratio （〈 50%） was much lower than that in pure water system. Major oxidation inter- mediates of tetrahydrofuran, including tetrahydro-2-fura- nol and y-butyrolactone, were detected indicating the engagement of THF in the BDE209 degradation process. The photocatalytic degradation of BDE209 in the pure water system followed first-order kinetics. The BDE209 degradation rate constant increased from 0.0011 to 0.0023 min-1 as the pH increased from 3 to 9.展开更多
A rapid, inexpensive and laboratory friendly method was developed for analysis of off-flavor/odor compounds in fresh and salt water using gas chromatography with chemical ionization-tandem mass spectrometry. Off-flavo...A rapid, inexpensive and laboratory friendly method was developed for analysis of off-flavor/odor compounds in fresh and salt water using gas chromatography with chemical ionization-tandem mass spectrometry. Off-flavor/odor compounds, included geosmin, 2- methylisobomeol （MIB）, 2-isobutyl-3-methyoxypyrazine （IBMP）, and 2-isopropyl-3-methoxypyrazine （IPMP）. Using this method, a single sample can be extracted within minutes using only 1 mL of organic solvent. The ion transitions for IPMP, IBMP, MIB, and geosmin were 153 〉 121, 167 〉 125, 152 〉 95, and 165 〉 109, respectively. The linearity of this method for analyzing MIB ranged from 4 to 200ng·L^-1, and from 0.8 to 200ng·L^-1 for the other analytes. Method recoveries ranged from 97% to 111% and percent relative standard deviations ranged from 3% to 9%, indicating that the method is accurate, precise, and reliable.展开更多
文摘Due to the low water solubility of polybromi- nated diphenyl ethers, organic solvent is usually added into the oxidation system to enhance the removal efficiency. In this study the photocatalytic degradation of decabromodi- phenyl ether （BDE209）, a type ofpolybrominated diphenyl ether used throughout the world, in pure water without the addition of organic solvent was investigated. In the pure water system, BDE209 was not dissolved but dispersed as nano-scale particles with a mean diameter of 166 nm. Most of BDE209 （〉 98%） were removed within 4 h and the final debromination ratio was greater than 80%. Although the addition of organic solvent （tetrahydrofuran, THF） could lead to a relatively high BDE209 degradation rate, the final debromination ratio （〈 50%） was much lower than that in pure water system. Major oxidation inter- mediates of tetrahydrofuran, including tetrahydro-2-fura- nol and y-butyrolactone, were detected indicating the engagement of THF in the BDE209 degradation process. The photocatalytic degradation of BDE209 in the pure water system followed first-order kinetics. The BDE209 degradation rate constant increased from 0.0011 to 0.0023 min-1 as the pH increased from 3 to 9.
文摘A rapid, inexpensive and laboratory friendly method was developed for analysis of off-flavor/odor compounds in fresh and salt water using gas chromatography with chemical ionization-tandem mass spectrometry. Off-flavor/odor compounds, included geosmin, 2- methylisobomeol （MIB）, 2-isobutyl-3-methyoxypyrazine （IBMP）, and 2-isopropyl-3-methoxypyrazine （IPMP）. Using this method, a single sample can be extracted within minutes using only 1 mL of organic solvent. The ion transitions for IPMP, IBMP, MIB, and geosmin were 153 〉 121, 167 〉 125, 152 〉 95, and 165 〉 109, respectively. The linearity of this method for analyzing MIB ranged from 4 to 200ng·L^-1, and from 0.8 to 200ng·L^-1 for the other analytes. Method recoveries ranged from 97% to 111% and percent relative standard deviations ranged from 3% to 9%, indicating that the method is accurate, precise, and reliable.
