How feasible is packing oxidants for their use in treatment of contaminated sites

Protection of different active ingredients is recognized as quite an old practice (in 1931 gelatine microspheres
were obtained by coacervation process) and it quickly developed, with applications in pharmaceutical,
textile and food industries, and lately for products applied in agriculture. Coating or encapsulating different
chemicals implies placing an external “shell”, with protective role, on a core of active ingredient. The final
product is a micro-particle, under the form of individual core-shell micro-capsule or a matrix, with more
active particulates embodied in. Many physical and chemical techniques have been used for packing
ingredients, which were, in most of the cases, chemical substances amenable to be consumed / selfdepleted before being active for a specific role. For application in environmental technologies a major
challenge is raised by the high chemical reactivity of reagents, especially oxidants, often used for the synthesis
or chemical transformation of the potential shell materials. Still, some oxidants were reported to have been
packed (Sodium Persulfate or Percarbonate, Potassium Permanganate, too), and the final products were
particles in the range of hundreds ìm – cm, which released the oxidant in interval of hours - days. Obtaining
microcapsules in the range of micrometric size (< 100 ìm), with slow regent release is an additional
challenge. More preparation methods were experimentally developed (e.g. in-situ polymerization,
coacervation or double layer coating) for Potassium Permanganate coating. Better results are obtained
when using physical methods, although the economical feasibility is questionable even when using the
most cost-efficient methods.