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The process of the ozone dissolution with decomposition in a rotating packed bed (RPB) is studied for model establishment. The RPB, which provides a high gravitational force by adjusting the rotational speed, is taken as a novel ozone contactor because of its high mass-transfer coefficient. It has a high potential to improve the ozonation performance or reduce the ozone contactor volume by applying RPBs. The objective of this study is to investigate and model the dynamic ozone dissolution process with decomposition in a RPB with oxygen mass transfer. In addition, the empirical correlations between the system parameters (including liquid holdup, liquid film thickness, specific area of the gas-liquid interface a, and mass-transfer coefficient k L 0 ) and operating conditions are presented. Furthermore, the variations of gas and liquid ozone concentration profiles are predicted to illustrate the dynamic behavior of mass transfer in a RPB. The validity of the model is demonstrated by comparing the predicted results with experimental data, indicating good agreement. As a result, the present model is useful and referable for the proper description of ozone contacting in a RPB system. IntroductionOzone is widely used as an oxidant applied in the water treatment and disinfect ion. The mixture of gases composed of oxygen and ozone is transferred to water by injecting it through the gas-liquid contactor. The efficiency of the ozonation processes is usually dependent on the dissolved ozone concentration. In addition, the rate-limiting step in many ozonation processes is attributed to gas-liquid mass transfer. 1 This means that the performance of the ozonation treatment is generally restricted to the gas-liquid mass-transfer rate of ozone. Consequently, the promotion of a gas-liquid contactor with high mass-transfer efficiency is desired.The rotating packed beds (RPBs) were used as gasliquid contactors for the applications of adsorption, distillation, stripping, etc. 2,3 According to the previous studies, RPBs have higher gas-liquid mass-transfer coefficients, which is an important factor for evaluating the gas-liquid mass-transfer rate. RPBs are designed to generate high acceleration due to centrifugal force. The novel technology is also named "Higee". The volumetric gas-liquid mass-transfer coefficients achieved in the RPB are 1-2 orders of magnitude higher than those in a conventional packed bed. 4 Recently, the RPB has been introduced by Lin and Liu 5 as an ozonation contactor. Compared to the conventional ozone contactors such as bubble column reactors (BCRs) and mechanically stirred reactors (MSRs), there is a high potential to enhance the ozonation performance or reduce the contactor volume by using RPBs.The concentration of ozone is usually relatively low with respect to that of oxygen in the carrier gas. One of the advantages of ozone dissolution is its contribution to dissolved oxygen, which can be used in the biological

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Biosorption has been shown to be an eco-friendly approach to remove heavy metal ions. In this study, the photosynthetic bacteria Rhodobacter capsulatus was screened and found to have strong ability to adsorb Au(III). The maximum specific uptake of living cells was over 92.43 mg HAuCl(4)/g dry weight of cell in the logarithmic phase. Biosorpion ability would be enhanced by an acidic environment. As the main cations, during biosorption the quantity of Mg(2+) exchanged was more than Na(+). Biosorbed Au(III) could be reduced by carotenoid and enzymes embedded and/or excreted by R. capsulatus, which might be the mechanism of photosynthtic bacteria metal tolerance.