Use of recycle waste metal shavings as catalysts for advanced oxidation process applied to water treatment

Abstract

In the last decades, the great industrial and demographic development has led to an unsustainable increase in the consumption of energy and raw materials that negatively affects the environment. This entails an increase in waste and generated contamination, especially organic micropollutants that require specific treatments in addition to a high operating cost. Therefore, alternatives and low cost treatments are studied these days in order to eliminate them effectively and avoid potential risks to the environment and human health. Advanced Oxidation Processes (AOPs) are based on their ability to generate hydroxyl radicals (HO·). The combination of an oxidizing agent (e.g. H2O2), a catalyst (e.g. Fe (ll)) and energy (e.g., UV radiation) produce this species with a high oxidation potential, which is capable of oxidizing most compounds in a non-selectively way. In this project, we used metal-based catalysts for promoting Fenton-like reaction in acidic or neutral pH to wastewater treatment. It is used to complete mineralization of the pollutants or their degradation in more easily biodegradable substances. The intention is to develop an effective alternative for elimination of the organic contaminant of the effluents and to test the use of a low-cost abundant product (waste metal shavings from metalworking industry) from an economic and environmental point of view. Zero Valent Iron (ZVI) and waste metal shavings (WMS) from metalworking industry are used as a catalysts and Sulfamethoxazole (SMX) was selected as model emerging pollutant in synthetic water. It is studied the different variables to optimize this Fenton-like process as the conditions of the catalysts and their most optimal concentration. Fenton oxidation as a combination of waste metal shavings with H2O2 at acid pH to generate hydroxyl radicals is a potential alternative or a complementary solution to conventional wastewater treatment processes for industrial wastewater treatment. An advantage it is that the waste metal shaving can be used over without requiring regeneration or replacement and can be removed from the treated water by sedimentation or filtration.