Amorphous silica waste from a geothermal central as an adsorption agent of heavy metal ions for the regeneration of industrial pre-treated wastewater

Abstract

An industrial wastewater regeneration treatment was successfully designed taking advantage of the amorphous silica adsorption properties, generated as an industrial waste in a geothermal power plant located in the city of Mexicali, Baja California. A tertiary wastewater process for the removal of heavy metals from a pre-treated galvanic industry effluent was designed by using a suspension-filtering system, employing previously purified amorphous silica (99.40% by weight) as an adsorbent of metal ions.The use of the amorphous silica allows to eliminate monovalent and divalent metal ions; 61.19% of silver, 96.28% of Cadmium and up to 98% of zinc, copper, nickel and lead; present in a standard prepared sample solution and between 39.56% and 84.22% of nickel, copper and zinc in a pre - treated industrial sample, achieving a good effluent quality with optimal chemical-physical conditions for its use. Keywords: Amorphous silica, Adsorption agent, Water regeneration, Heavy metals, Geothermal central, Metal removal, Wastewater