Algae-mediated copper nanocatalyst for aerobic oxidation and dye decolourization via sustainable wastewater treatment

In recent years, several physicochemical methods have been proposed for decolourising textile dyes; however, few have been adopted by the textile industry because of factors such as high cost, low efficiency, and limited applicability to a wide range of dyes. The current study focuses on synthesising algae-mediated Cu and CuO nanocatalysts (Alg-Cu and Alg-CuO) using natural waste materials from green algae. The synthesised Alg-CuO nanocatalyst was characterised and confirmed using SEM, TEM, UV, FT-IR, XRD, XPS, GC-MS, and TGA. An innovative and efficient technique for decolourising dyes through aerobic oxidation was implemented in industrial wastewater treatment. Various hydroxylamine substrates were successfully transformed into the desired aldehydes using an Alg-CuO nanocatalyst. In the process of aerobic oxidation, 2-(2-amino-ethyl)-aminoethanol can be converted into 2-(2-amino-ethyl)acetaldehyde, resulting in 96% product conversion within 4 min. In addition, the synthesised Alg-CuO nanocatalyst was used to investigate the dye decolourisation process using CBB G250 dye. The Alg-CuO nanocatalyst exhibited excellent decolourisation properties; for 20 min, 85% decolourisation of the CBB G250 dye was achieved. As a result, green synthesis is a viable medium for producing Alg-CuO nanocatalysts with high bond energies for dye decolourisation. Finally, the dye and Alg-CuO nanocatalyst was separated and reused for the following process. This method has been used for industrial wastewater treatment.