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BACKGROUND: The importance of potable water is immeasurable and its contamination by pollutants is a serious environmental problem. Rhodamine B (RhB), one such pollutant, is highly toxic to various organisms and may cause long-term undesirable effects when improperly disposed of. Thus, development of an efficient treatment technique is necessary. Among the new oxidation methods, heterogeneous photocatalysis is an emerging pollutant destructive technology. RESULTS: The photocatalytic activities of copper (Cu) and zinc (Zn) aluminate spinels (CuAl 2 O 4 and ZnAl 2 O 4 ) was evaluated.Chemical and physical properties were considered, and ZnAl 2 O 4 showed higher RhB degradation efficiency (73.90% in only 10 min) than CuAl 2 O 4 (51.95% in 10 min), reaching up to 100% in 30 min. According to results, a further RhB catalytic degradation pathway by ZnAl 2 O 4 was monitored by UV-visible spectrometry and ultra-high performance liquid chromatography coupled to diode array detection (UHPLC-DAD) analysis. When applied to wastewater from gemstone beneficiation, containing elevated RhB concentration, the ZnAl 2 O 4 caused 88% color removal in 120 min and its pollutant removal rate was 18 times greater than the commonly used ZnO.CONCLUSION: The superior performance of ZnAl 2 O 4 can be attributed to better pore properties, responsible for providing more active sites. These identified reactive oxygen species (ROS)-induced interactions and the species demonstrated that degradation occurs due to generation of O 2•and h + . Thus, ZnAl 2 O 4 proved to be an efficient photocatalyst for quick RhB pollutant degradation with promising potential for real wastewater treatment applications. CONCLUSIONBoth Cu and Zn aluminate spinels presented elevated catalytic performance, but when compared, ZnAl 2 O 4 presented higher J Chem Technol Biotechnol 2020; 95: 791-797

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Real hospital wastewater was effectively treated by a promising technology based on degradation reaction catalyzed by Fe0 under microwave irradiation in this work. Fe0 powders were synthesized and characterized by different techniques, resulting in a single-phase sample with spherical particles. Optimum experimental conditions were determined by a central composite rotatable design combined with a response surface methodology, resulting in 96.8% of chemical oxygen demand reduction and 100% organic carbon removal, after applying MW power of 780 W and Fe0 dosage of 0.36 g L−1 for 60 min. Amongst the several organic compounds identified in the wastewater sample, diclofenac and ibuprofen were present in higher concentrations; therefore, they were set as target pollutants. Both compounds were completely degraded in 35 min of reaction time. Their plausible degradation pathways were investigated and proposed. Overall, the method developed in this work effectively removed high concentrations of pharmaceuticals in hospital wastewater.

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