Azo dyes are recalcitrant pollutants present in effluents of several industries. Due to their chemical stability, their degradation efficiency is not satisfactory by conventional technologies. Advanced oxidation processes, such as Fenton, can be applied for the removal of recalcitrant compounds. However, these methods are still costly. In this work, Fenton and precipitation treatments were combined for the removal (i.e., decolorization) of direct blue 1 (DB1), as an option to decrease operational costs. The individual treatments were studied separately using DB1 solutions 0.04 mmol L-1 to determine the effects of the parameters involved in each process. For the Fenton treatment, the c(Fe2+):c(H2O2) ratio that allowed the highest DB1 decolorization was 1:40. Regarding precipitation, the highest dye decolorization was achieved at a pH value of 6.0. Moreover, it was determined that a minimum c(DB1):c(Fe2+) ratio of 1:7.7 is needed to allow the decolorization of the dye by precipitation. Fenton assisted with precipitation tests were performed with DB1 solutions 0.09 mmol L-1 and using a c(DB1):c(Fe2+) ratio of 1:7.3 (which allows only partial precipitation of DB1). The results suggested that the dye can be treated by a Fenton process for 5 min and then precipitated to achieve the almost total decolorization of the dye (97.79 %). Azo dyes are recalcitrant pollutants present in effluents of several industries. Due to their chemical stability, their degradation efficiency is not satisfactory by conventional technologies. Advanced oxidation processes, such as Fenton, can be applied for the removal of recalcitrant compounds. However, these methods are still costly. In this work, Fenton and precipitation treatments were combined for the removal (i.e., decolorization) of direct blue 1 (DB1), as an option to decrease operational costs. The individual treatments were studied separately using DB1 solutions 0.04 mmol L-1 to determine the effects of the parameters involved in each process. For the Fenton treatment, the c(Fe2+):c(H2O2) ratio that allowed the highest DB1 decolorization was 1:40. Regarding precipitation, the highest dye decolorization was achieved at a pH value of 6.0. Moreover, it was determined that a minimum c(DB1):c(Fe2+) ratio of 1:7.7 is needed to allow the decolorization of the dye by precipitation. Fenton assisted with precipitation tests were performed with DB1 solutions 0.09 mmol L-1 and using a c(DB1):c(Fe2+) ratio of 1:7.3 (which allows only partial precipitation of DB1). The results suggested that the dye can be treated by a Fenton process for 5 min and then precipitated to achieve the almost total decolorization of the dye (97.79 %).

Meropenem (MER), a carbapenem, is considered a last-resort antibiotic. Its presence in water bodies, together with other antibiotics, has brought about environmental problems related to the destruction of natural microorganisms and the development of antibiotic-resistant bacteria. Herein, the degradation of MER by heterogeneous photocatalysis using TiO2 immobilized on fiberglass substrates is reported. Morphological characterization of the substrates was performed by Scanning Electron Microscopy (SEM). Three pH values (4.0, 5.7, and 7.9) were tested for the treatment of MER solutions (100 mg/L). The best rate constants and MER removals were obtained at pH 4.0 (0.032 min−1; 83.79%) and 5.7 (0.032 min−1; 83.48%). Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) removals of 25.80% and 29.60% were achieved for the treatment at a pH value of 5.7. The reuse and regeneration of the plates were also tested. The activity of the substrates was maintained until the fourth cycle of reuse, nonetheless, a decrease in MER removal was observed for the 5th cycle. After the fourth cycle of reuse, the activity of the substrates was recovered by a regeneration procedure involving a wash stage of the substrates with a 1% H2O2 solution in an ultrasonic bath.