Ribeiro, RuiRodrigues, Raquel OliveiraSilva, AdriánTavares, Pedro B.Carvalho, Ana MariaFigueiredo, JoséFaria, JoaquimGomes, Helder2018-01-312018-01-312018-01-312018-01-312017Ribeiro, Rui; Rodrigues, Raquel Oliveira; Silva, Adrián M.T.; Tavares, Pedro B.; Carvalho, Ana M.C.; Figueiredo, José L.; Faria, Joaquim; Gomes, Helder (2017). Hybrid magnetic graphitic nanocomposites towards catalytic wet peroxide oxidation of the liquid effluent from a mechanical biological treatment plant for municipal solid waste. Applied Catalysis B: Environmental. ISSN 0926-3373. 219, p. 645-6570926-3373http://hdl.handle.net/10198/15377Magnetite, nickel and cobalt ferrites were prepared and encapsulated within graphitic shells, resulting in three hybrid magnetic graphitic nanocomposites. Screening experiments with a 4-nitrophenol aqueous model system (5 g L −1 ) allowed to select the best performing catalyst, which was object of additional studies with the liquid effluent resulting from a mechanical biological treatment plant for municipal solid waste. Due to its high content in bicarbonates (14350 mg L −1 ) and chlorides (2833 mg L −1 ), controlling the initial pH was a crucial step to maximize the performance of the catalytic wet peroxide oxidation (CWPO) treatment. The catalyst load was 0.5 g L −1 , a very low dosage when compared to the high chemical oxygen demand (COD) of the effluent − 9206 mg L −1 . At the optimum operating pH (i.e., pH = 6), ca. 95% of the aromaticity was converted and ca. 55% of COD and total organic carbon (TOC) of the liquid effluent was removed. The biodegradability of the liquid effluent was enhanced during the treatment by CWPO, as reflected by the 2-fold increase of the five-day biochemical oxygen demand (BOD 5 ) to COD ratio (BOD 5 /COD), namely from 0.21 (indicating non-biodegradability) to 0.42 (suggesting biodegradability of the treated wastewater). In addition, the treated water revealed no toxicity against selected bacteria. Lastly, a magnetic separation system was designed for in-situ catalyst recovery after the CWPO reaction stage. The high catalyst stability was demonstrated through five reaction/separation sequential experiments in the same vessel with consecutive catalyst reuse.engCore-shell nanocompositesHeterogeneous Fenton-like processMagnetic separationMechanical biological treatmentProcess waterjournal article10.1016/j.apcatb.2017.08.013