Complex interplay between colloidal stability, transport, chemical reactivity and magnetic separability of polyelectrolyte-functionalized nanoscale zero-valent iron particles (nZVI) toward their environmental engineering application
Wei Ming Ng, JitKang Lim
Abstract
The dual reactive and magnetic functionalities of nanoscale zero-valent iron (nZVI) have made it to become one of the most intensively studied nanomaterials for environmental engineering application. These nanoiron particles possess high reactivity due to their high specific surface area and strong reducing power for different kind of contaminants. However, the rapid agglomeration of nZVI to form large clusters due to the strong magnetic dipole-dipole interaction results in poor colloidal stability, reduced mobility and low reactivity. Surface functionalization with polyelectrolyte is often proposed to provide stabilization for the nanoparticles via electrosteric repulsion. This paper discusses the effect of surface functionalization on performance of nZVI as a result of complex interplay between the colloidal stability, mobility, reactivity and magnetic separability for environmental application. We illustrate the role of the polyelectrolytes in controlling interparticle and environmental interaction of the nZVI and highlight the associated challenges encountered in the field application of nZVI.