I am modeling cadmium transportation in consideration of reactions-adsorption and precipitation/dissolution in a column packed with fly ash and bentonite mixture. For this purpose, I performed batch experiments about cadmium to know surface complexation properties and tracer experiments to know hydrogeological parameters-seepage velocity and dispersion coefficient- using lithium bromide. First to consider the adsorption properties of cadmium on the mixture I used SURFACE_SPECIES and SURFACE. The column experiment of bromine was simulated using TRANSPORT. And then, I combined two models of surface complexatoin and conservative transport to simulate non-conservative transport of cadmium. However, I found some problems about my results and had questions about them. 1. To define SURFACE, are SURFACE and their total mass also divided by 10 if I divided column to 10 cells? 2. In the case of my experiments, the removal rate of cadmium was very low in a range of 5~200mg/L. So I changed reaction constants (log_K) of SURFACE_SPECIES to negative values. Is it caused any problem? 3. I performed breakthrough experiment for a single ion of cadmium. But the BTC showed the shooting result that appears in multi-ion (I mean the concentration near the breakthrough is over the initial concentration). I think that result was caused by the other ions that were defined for PHASES. How can I remove such a phenomenon? 4. I included surface complexation to account for the retardation of cadmium in a column. So I expected that cadmium flowed out more slowly in the low concentration. Though I changed the initial concentrations from 50mg/L to 5mg/L, the breakthrough times are much the same. Why did the results appear? I attach input files to e-mail. I know they may be very clumsy and improper. I believe you will give me a proper advice. _____________________________________________________________________ 예쁜 편지지에 메일을 보내세요 - 야후! 메일 http://mail.yahoo.co.kr 신차,중고차,직거래 매물이 한자리에 - 야후! 자동차 http://autos.yahoo.co.kr/autos/
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