Reference concentration of colloids in C_ride

A discussion forum for users of the new HYDRUS 2D/3D. HYDRUS is a software package for simulating water, heat and solute movement in two- and three-dimensional variably saturated media. Happy Posting!
Post Reply
Dan Zhou
Posts: 3
Joined: Fri Mar 05, 2021 3:16 am
Location: China

Reference concentration of colloids in C_ride

Post by Dan Zhou » Thu Jan 13, 2022 12:06 pm

Hello everyone,

(1)In the C-ride mode, how to define the reference concentration of colloids Cc_ref and Sc_ref ? I do not know what specific value I should give.

(2)Do you think the solute sorption rate to the mobile colloid is equal to the immobile colloid? In my opinion, they are equal since the mobile colloid and immobile colloid actually are the same particle. But the parameters listed in Table 3 (Simunek, 2006) of Cd sorption rate to mobile and immobile colloids are different. What is your opinion?

Best wishes,

Dan

Jirka
Posts: 5374
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Reference concentration of colloids in C_ride

Post by Jirka » Thu Jan 13, 2022 8:05 pm

Ad 1: I do not have any guidance what those values should be. They depend on how the solute sorption rates to colloids were determined. These rates should obviously depend on the number of colloids in the system. I.e., solute sorption to colloids is faster if there is more colloids in the systems, and vice versa.

Ad 2: It may or it may not. Yes, both mobile and immobile colloids are likely the same. However, while the entire surface area of mobile colloids may be subject to sorption, a fraction of the surface area of immobile colloids may not be accessible to solute sorption, reducing the sorption rate.

J.

Dan Zhou
Posts: 3
Joined: Fri Mar 05, 2021 3:16 am
Location: China

Re: Reference concentration of colloids in C_ride

Post by Dan Zhou » Fri Jan 14, 2022 12:39 am

Many many thanks, Jirka. Your quick response is the greatest support to this community.

(1) OK.
(2) You are right, they can be different because the available surface area is different.

Best regards,

Dan

Post Reply