| As beta-blockers, atenolol, propranolol and nadolol have been used for a long time in North America. Also previous studies indicated that these three beta-blockers were detected in aquatic environmental waters at &mgr;g L -1 level and were hard to remove by traditional technologies effectively. Gamma radiation, which has been known as Advanced Oxidation Process (AOP), can perform an effective degradation of beta-blockers. The figure-of-merit electric energy per order (EE/O) has been proven a good indicator to evaluate the performance of AOPs. In this study, we conducted gamma radiation experiment to perform a destruction of beta-blockers. EE/O has been calculated to the removal of beta-blockers from distilled water, both individually and as mixtures. EE/O of atenolol, nadolol and propranolol provided by calculated results are 340.41, 190.38 and 346.20 (kWh/m3/order), respectively. In most cases the EE/O of given beta-blocker mixed with increased a little. However, when three compounds are mixed, EE/O of all beta-blockers will increase dramatically by 280%–580%. We also related EE/O values in the study to the energy footprints and corresponding carbon footprints in multiple ways. Comparison shows that in some cases removal of two beta-blockers' mixture is more economical than treating them separately. For the three compounds' mixture, every 10% incremental of removal percentage will cause nearly 33% higher energy footprints. |
