Optimisation of a concentration measurement sensor for nano sized zero valent iron using numerical simulation

The concentration of nano sized zero valent iron (nZVI) is an important criterion for the in-situ remediation of ground water contaminations. To measure the magnetic susceptibility of nZVI, two specified cylindrical coils with the desired measuring range and the corresponding post-processing algorithm (PPA) are presented to determine the concentration change of nZVI during the remediation process. To accurately calculate the concentration of nZVI, numerical simulations are required to evaluate the actual magnetic susceptibility of nZVI filled in the column and the change of the self-inductance of each coil because of nZVI. To improve the efficiency of the presented algorithm, an optimal frequency for the measurement is determined by taking into account the equivalent capacitance of the coil and the cable. Moreover, two special boundary conditions for the efficient calculation of the parasitic capacitances are presented. Finally, two experiments have been performed to verify the developed sensor and the measurement method.