Trachyspermum ammi Mediated Green Synthesis of NiO Nanoparticles: Dual Role in Photocatalytic Degradation and Anti-bacterial Efficacy

Nowadays, there is a lot of discussion in science about green chemistry of nanomaterials, from synthesis to various environmental applications. Herein, we describe a simple, environmentally friendly, economically feasible, free of additives, phytosynthetic methodology for the synthesis of cubic phased NiO nanoparticles using the seed extract of Trachyspermum ammi (also known as Ajwain), which acts as a capping and reducing agent that helps in reducing nickel sulphate (NiSO4.6 H2O) to NiO via co-precipitation method. Various spectroscopic techniques were involved in investigating the phase, morphology, functional groups, crystallinity, size, elemental confirmation, optical property with band gap of the green synthesised NiO Nanoparticles. Moreover, green NiO nanoparticles displayed excellent degradation efficiency for the reduction of industrial pollutant, Allura red and possible mechanism were also suggested. Nearly 91.73% of the Allura red was degraded using the synthesised NiO nanoparticles within 90 min when exposed to UV-light. Moreover, the used nanoparticles were renewed and again their photocatalytic performance was assessed for three consecutive cycles. In addition to photocatalytic activity, the green NiO nanoparticles revealed the considerable anti-bacterial activity against Staphylococcus aureus and Escherichia coli and the dead percentage was calculated as 92.56% and 94.33% respectively. In this work, green NiO nanoparticles was involved as a dual functioning agent for effective photocatalytic and anti-bacterial studies.