Ultrasound can be used to oxidize aqueous pollutants; however, due to economic reasons, higher oxidation/destruction rates are needed. This study reports enhancements of reaction rates by the addition of sodium chloride salt. Using 20 kHz ultrasound, large salt-induced enhancements are observed6-fold for chlorobenzene, 7-fold for p-ethylphenol, and 3-fold for phenol oxidation. The reaction rate enhancements are proportional to the diethyl ether−water partitioning coefficient of the pollutants. It appears that the majority of oxidation reactions occur in the bubble−bulk interface region. The addition of salt increases the ionic strength of the aqueous phase which drives the organic pollutants toward the bubble−bulk interface. A first order reaction rate equation is proposed which can represent the observed enhancement with a good accuracy. A new sonochemical-waste-oxidation process is proposed utilizing the salt-induced enhancement.

Ultrasound can be used to oxidize aqueous pollutants. However, due to economic reasons higher oxidation/destruction rates and higher energy efficiency are needed. Recent studies suggest that the higher ultrasound frequencies provide better oxidation rates than the conventional 20 kHz. Another area for improvement is reactor configuration. We have tested two new reactor configurations with proper focusing and reflection of ultrasound for maximum utilization. Reactor configuration plays an important role in the overall efficiency. In the new reactors, transducers and reaction mixture are separated by a polymer acoustic window which allows efficient transfer of ultrasound energy and not the heat from the transducer to the reaction mixture. One reactor at 640 kHz provides a 100% enhancement over the best reported rate for the oxidation of potassium iodide, on a per-Watt basis. Experiments conducted at varying initial KI concentrations show interesting behavior. Increasing the KI concentration by over eight fold merely increases the iodine production rate by two fold. This suggests that in the oxidation region surrounding the bubble, the KI concentration is much different than in the bulk. It is proposed that the hydrophobic bubble region has lower and near saturation KI concentration.

A major institution for the ethnic Han (Chinese) colonisation of Xinjiang is the Production and Construction Corps. Although quasi-military in origin, its military role is now eclipsed by its economic role. Traditionally it was primarily a collection of state farms, but in recent years its industrial enterprises have expanded. It has also played a role in imprisoning convicts from eastern China. Largely destroyed during the Cultural Revolution, it was actually abolished for a few years beginning in 1975. But the perceived need to project Chinese influence into the area, and to protect against ethnic unrest and Soviet pressures, persuaded the authorities that the Corps should be revived. Today the Corps has 2.8 million members, or 14 percent of Xinjiang’s population, and plays a significant role in the region’s economy.

No abstract

No abstract