Method for producing zero-valent metals in filtering media

A method for producing microparticles and/or nanoparticles and/or coverings containing at least one zero-valent metal inside a filtering medium, comprising the following steps:

• step 201) providing a second aqueous solution of at least one inorganic reducing agent;
• step 202) providing the filtering medium containing at least one metal or salt of the at least one metal, in a dissolved phase and/or a solid phase, and/or containing a fluid inside the filtering medium, static or flowing, having a non-zero concentration of the at least one metal present as the dissolved phase and/or the solid phase;
• step 203) introducing the second aqueous solution inside the filtering medium;
• step 204) allowing or inducing a mixing, inside the filtering medium, of the second aqueous solution with the at least one metal present in the filtering medium or in the fluid contained in the filtering medium, in order to produce the microparticles and/or the nanoparticles and/or the coverings containing the at least one zero-valent metal directly inside the filtering medium, thus modifying mechanical and/or electrical and/or chemical and/or chemical-physical and/or microbiological and/or hydrodynamic properties and/or geochemical and/or geotechnical and/or thermal and/or morphological and/or superficial properties of the filtering medium.

A method for remediation and/or a treatment of a filtering medium, wherein the filtering medium is a contaminated filtering medium and/or a remediation and/or a treatment of a contaminated fluid present inside the filtering medium, comprising the steps of:

• step 300) providing a first aqueous solution of at least one metal or a salt of the at least one metal;
• step 301) providing a second aqueous solution of at least one inorganic reducing agent;
• step 302) preparing the contaminated filtering medium for an introduction of the first aqueous solution of the step 300 and the second aqueous solution of the step 301;
• step 303a) introducing the first aqueous solution into the contaminated filtering medium;
• step 303b) introducing the second aqueous solution into the contaminated filtering medium;
• wherein amounts of the first aqueous solution of the step 303a and the second aqueous solution of the step 303b are in a predetermined mutual ratio;
• step 304) allowing or inducing a mixing, inside the contaminated filtering medium, of the first aqueous solution and a mixing, inside the contaminated filtering medium, of the second aqueous solution in order to produce microparticles and/or nanoparticles and/or coverings containing at least one zero-valent metal directly inside the contaminated filtering medium and/or to induce a reduction to a zero-valent, form of metals present on a surface of the filtering medium and/or the microparticles and/or the nanoparticles and/or the coverings containing the at least one zero-valent metal part of a solid matrix of the filtering medium and/or microparticles and/or the nanoparticles and/or the coverings containing the at least one zero-valent metal contained inside the fluid;
• step 305) allowing or inducing a contact between contaminants and the microparticles and/or the nanoparticles and/or the coverings containing the at least one zero-valent metal to induce a degradation, a transformation and/or an immobilization of the contaminants.