Ozan

Hey, I attached react and a surface data file that I have used in that react folder. This model should give me results of precipitation, dissolution, adsorbed/desorbed species related to co2 concentration in the system. However, except calcite (which has a significantly higher kinetic rate constant), I can not see any change in the other minerals in terms of mg. I tried using longer time intervals, still change in other minerals are 0 mg. I expected to see dissolution of albite, illite (which I see very small change) and precipitation of kaolinite and quartz. I would be happy if you could let me know if this problem is due to very small kinetic constants or am I building it wrong. I would appreciate any other advice related to the model (if there is any better way to assign minerals or species etc). Here is the link for the kinetic constants if you would like to check if I put them in a correct way https://pubs.usgs.gov/of/2004/1068/pdf/OFR_2004_1068.pdf . Thanks, Ozan kinetic_model.rea illitecationexchange.sdat

Thank you! RETURN worked! Ozan

I am trying to use the rate law attached in GWB react. I tried to define a custom rate law and wrote a script. However, calculated rate is not correct and does not change through time. I would be happy if you could help me with this. The script I wrote is below. Here is the publication I used for rate law https://pubs.usgs.gov/of/2004/1068/ . I would also be happy if you could let me know if there is any way to put three different k and E values without defining a custom rate law. Thank you! LET kacid = 5.012 * 10^(-1) * 10^(-4) LET kneut = 1.549 * 10^(-6) * 10^(-4) LET kbase = 3.311 * 10^(-4) * 10^(-4) LET Eacid = 14.4 * 10^(3) LET Eneut = 23.5 * 10^(3) LET Ebase = 35.4 * 10^(3) LET nacid = 1 LET nbase = 1 LET m1 = 1 LET m2 = 1 LET m3 = 1 x = kacid * EXP ((-Eacid / 8.314) * ((1/TK)-(1/298.15))) * (activity("H+")^(nacid)) * (1-(QoverK)^(m1))^(m1) y = kneut * EXP ((-Eneut / 8.314) * ((1/TK)-(1/298.15))) * (1-(QoverK)^(m2))^(m2) z = kbase * EXP ((-Ebase / 8.314) * ((1/TK)-(1/298.15))) * (activity("H+")^(nbase)) * (1-(QoverK)^(m3))^(m3) rate = surface * (x + y + z)

Hey, I am trying to built a sorption database according to minerals and elements that I am interested in. I encounter so many surface complexation models such as; Constant Capacitance (CC), CD-MUSIC (CDM), Diffuse Double Layer (DDL), Extended Constant Capacitance (ECC), Ion Exchange (Iex), Non-electrostatic (NE), Triple Layer (TL), 1pK-Basic Stern (1pK-BS). I know that (from GWB Essentials) GWB can use two-layer surface complexation which includes constant capacitance, constant potential and Ion Exchange. My question is about DDL which is also double layer and I guess it is equal to constant potential. Is constant potential or DDL is a different model? Also, constant potential does not consider electrostatic interactions and NE also does not consider electrostatic interactions. So, is constant potential and NE are same models? I guess GWB does not model TL or CDM, could you please confirm that and give me more information if GWB can model any other surface complexation model. I am lost under many different names. I also checked out the book for these information but I couldn't find more. Here is the website I am using to find out the sorption data and these models (and explanation of models); https://www.hzdr.de/db/RES3T.login Thanks! Ozan