Coupled differential equations MATLAB

Hello,

I want to solve a system with coupled differential equations. The model representation is given in the attached photo.

Basically one differential equation describes the mass balance of ions in liquid phase in the z-direction. The other differential equation describes the mass balance of ions in the solid phase in the x-direction.

This makes two differential equations in two different directions. I would like to know how to solve such a system on MATLAB.

P.S. the author this research paper mentioned that they first discretized the differential equations by the finite difference method into algebraic nonlinear equations. Any help along those lines would also be appreciated.

Thanks in advance.

[Torsten]

Look up "Method of Lines".