Hybrid magnetic graphitic nanocomposites towards catalytic wet peroxide oxidation of the liquid effluent from a mechanical biological treatment plant for municipal solid waste

• Type: Article in International Scientific Journal
• Date: 2017

Authors

Rui S. Ribeiro (Author) FEUP; Raquel O. Rodrigues (Author) FEUP; Adrián M.T. Silva (Author) FEUP; Pedro B. Tavares (Author) Other; Ana M.C. Carvalho (Author) Other; José L. Figueiredo (Author) FEUP; Joaquim L. Faria (Author) FEUP; Helder T. Gomes (Author) Other

Journal

Title: Applied Catalysis B: Environmental

Vol. 219

Pages: 645-657

ISSN: 0926-3373

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 8 Citations

ISI Web of Science

Scopus - 14 Citations

Other information

Authenticus ID: P-00M-XKZ

DOI: 10.1016/j.apcatb.2017.08.013

Abstract (EN): Magnetite, 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 (BOD5) to COD ratio (BOD5/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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 13