Intensified degradation of pharmaceutical effluents by novel aerobic iron-swarf activated molecular oxygen in the presence of ascorbic acid

摘要

An intensified degradation of antibiotics-based pharmaceutical effluent using novel green and clean technology-based process was proposed, in which molecular oxygen was activated by iron swarf in the presence of non-toxic ascorbic acid. In this process, molecular oxygen present in air has been used as oxidant in the place of conventional hydrogen peroxide and an ecofriendly ascorbic acid has been used as reductant to reduce less reactive Fe(III) to desired Fe(II). The degradation was performed in air-lift reactor and purpose of air-lift reactor not only facilitates better mass transfer but also supplies the oxidant for reaction. Three different effluents (having different properties) were collected and named SAM1, SAM2 and SAM3. The various parameters that influencing degradation were studied and the optimal values of reaction time (180 min), dosage of ascorbic acid (600, 500 and 400 mg/L for SAM1, SAM2 and SAM3, respectively), reaction temperature (35 degrees C) and optimal pattern of iron addition (multiple additions) were determined. Under this optimal condition, the proposed treatment produced more promising results (COD reduction of 92.1%, 81.2% and 71.4%, respectively) and the degradation follows second-order kinetics. The ecotoxicity study showed that, the treated effluents were less toxic than the parent pollutant. Thus, this work clearly shows that, the proposed methodology is not only cost-effective but also a green and clean technology, without compromising the rate of degradation.