Azadirachta indica leaf extract-derived NiS@Functionalized biochar catalyst: Efficient acetalization and enhanced reusability in photodegradation of tinidazole

Growing biodiesel production creates a significant volume of glycerol (Gly), a by-product that must be transformed into valuable compounds by developing novel and sustainable technologies. Solketal is one of several valuable compounds derived from residual Gly released during biodiesel synthesis. A green synthetic process followed by the co-precipitation method was used to fabricate NiS@Functionalized Biochar (NBS) using Azadrichta indica leaf extract. The nanocatalyst was extremely active for microwave-assisted solketal synthesis from Gly and acetone. A 99.7 ± 0.3 % conversion of Gly with 100 % solketal selectivity occurred under the optimum reaction conditions (catalyst loading 4 wt%, Gly to acetone molar ratio 1: 5, reaction time 6 min, and temperature 65 °C). The suggested reaction mechanism demonstrates the selective synthesis of solketal. The NBS catalyst showed excellent reusability up to six cycles, and after that, it was used for the photodegradation of tinidazole, where 89.14 % degradation efficiency was obtained within 110 min of sunlight irradiation. A narrow energy band gap (1.99 eV) and effective charge separation favor the photocatalytic activity of the reused catalyst. The environmental friendliness of the catalyst for the solketal synthesis process was examined by studying green metrics.