Gum arabic-assisted green synthesis of biocompatible MoS₂ nanoparticles for methylene blue photodegradation

The current work reports the gum arabic-mediated greener synthesis of MoS₂ nanoparticles (NPs) and its utilization for the solar light-assisted degradation of methylene blue. Furthermore, the safety analyses were performed on human-beneficial gut bacterium, L. delbrueckii, and human blood cells to confirm the biocompatibility of NPs synthesized. Antioxidant and antimicrobial activities were done to explore their usefulness for biological applications. Sonication and microwave treatment were used to obtain spherical 10-12 nm MoS₂ NPs as characterized using high-resolution transmission electron microscopy. FT-IR characterization revealed the occurrence of gum arabic on the NPs surface. The MoS₂ NPs exhibited ~ 98% MB degradation within 8 h under direct sunlight exposure. Moreover, the reusability studies have also been evaluated and free radical trapping experiments indicated that superoxide (•O₂^-) is the dominant active species of the reaction system. Furthermore, 98.89% MB degradation efficiency was observed within 150 min in the case of real textile industry MB effluent samples. Untreated MB inhibited the growth of L. delbrueckii on MRS agar plates, while growth was observed in the case of MoS₂ NPs-treated MB samples indicating safety of current MB degradation approach. MoS₂ NPs inhibited the growth of E. coli MTCC1698 and S. aureus MTCC 3160 with 26 mm and 21 mm zone of inhibition, respectively. Furthermore, MoS₂ NPs have shown antioxidant properties, resulting in 82.3 ± 0.43% of DPPH scavenging activity which was comparable to ascorbic acid (81.6 ± 0.6%), a standard antioxidant molecule. The NPs have not shown any hemolytic activity at 0.0625 and 0.125 mg/mL doses to human blood proving their biocompatible nature. Gum arabic-synthesized biocompatible MoS₂ NPs have good potential to treat MB released as waste from the textile industry and other biological applications.