Abstract:
This Master thesis presents the development and evaluation of a continuous microreactor system based on the Fe(II)/periodate process for the rapid degradation of organic dyes in industrial effluents, using Cibacron Green H3G as the model pollutant. Mechanistic investigations, employing selective scavengers and surfactant tests, demonstrated that periodate activation occurs primarily at the surface of nZVI, generating mainly Fe(IV) and IO₃• radicals, while hydroxyl radicals (•OH) are negligible under these conditions.
In continuous operation, the main operational parameters (periodate and dye flow rates, pH, Fe(II) dosage) were systematically optimized. An acidic pH (3) and an Fe(II) dosage of
0.05 mM proved optimal for maximizing pollutant conversion. High periodate flow rates enhanced degradation up to the point where residence time became limiting, indicating the need to balance oxidant dose and contact time to achieve maximum efficiency.
The influence of real water matrices (mineral water, river water, seawater, and secondary effluents from wastewater treatment plants) was analyzed: inhibition increased with matrix complexity, attributable to natural organic matter and competing ions. However, raising the periodate dose partially offset these inhibitory effects, demonstrating the process’s flexibility while underscoring the need for pretreatment or coupling strategies when treating highly loaded effluents
