Nanocrystalline cellulose derived from melon seed shell (Citrullus colocynthis L.) for reduction and stabilization of silver nanoparticles: Synthesis and catalytic activity

Melon seed shells (MSS) are a hazard to the environment as they host disease vectors. To alleviate the effect, we explored melon seed shells (MSS) as a new source of nanocrystalline cellulose (NCC) with reducing- and stabilizing capacity for the synthesis of silver nanoparticles (AgNPs). The isolation of NCC from discarded MSS served the dual purpose of a reducing- and stabilizing agent in the synthesis of AgNPs. The isolated needle-like crystals (MSS-NCC) had a mean length 204 nm, width 7 nm and aspect ratio 30. The NCC had crystallinity index of 94% with surface rich in -OH and -COOH functionality. The obtained AgNPs covered the surface of the MSS-NCC and catalysed the reduction of nitrobenzene to aniline using NaBH4. The process of the reduction monitored via UV-vis spectroscopy was completed within 12 min. with a rate constant 0.04 min(-1) as revealed by the kinetic study.

Automated summary

Melon seed shells were explored as a new source of nanocrystalline cellulose (NCC) for the synthesis of silver nanoparticles (AgNPs), and were found to have reducing capability. The isolated crystals (MSS-NCC) had a high crystallinity index and were rich in functional groups on the surface. The AgNPs synthesized using MSS-NCC as a reducing agent showed efficient catalytic activity in reducing nitrobenzene to aniline.