Transforming Tea Wastes into Carbon Dots Based nano Product for its Applications as Plant Bio Stimulant

Abstract

newlineCarbon nanotechnology offers sustainable solutions in many sectors, including newlineagriculture through eco-friendly and green synthesis of carbon dots (C-Dots) from waste newlinebiomass. The growing consumption of tea and its products leads to an abrupt rise in waste newlinethat is being generated from the tea industry, resulting in significant biomass loss and newlineenvironmental stress. In recent years, interest has been attracted on utilization of tea waste newlinebiomass, and very few works have been reported so far in this area. newlineInitial studies were conducted to prepare C-Dots from three different tea wastes, newlinenamely garden tea waste (GTW), tea processing waste (TPW) and spent tea waste (STW) newlinein a sustainable manner without the use of neither harmful corrosive acids nor energy newlineexpensive methods. The current study employs a two-step sequential process by combining newlinepyrolysis and ultra sonication, for synthesizing the C-Dots with higher recovery rate when newlinecompared to pyrolysis alone. Further, we established a cost-effective approach for newlineproducing stable carbon-dots based bio-stimulant nano formulation (C-Dots NF). In this, newlinesynthesized C-dots were developed into a nano emulsion for enhanced storability while in newlinetransit and wettability during foliar application over tea leaf surface. The nano emulsion newlinewas prepared by blending organic phase (clove oil) with polysorbate 80 surfactant and newlineaqueous phase dispersed with carbon dots. newlineA series of characterization techniques were utilized to investigate the newlinemorphological, functional and optical properties of C-Dots and C-Dots NF, followed by newlinefield investigations and biosafety studies to evaluate the effect of pristine C-Dots and newlineC-Dots NF over tea plantations and beneficial microorganism. newlineThe average size of C-Dots (2-5 nm) was measured using HRTEM. The Zeta newlinepotential value of C-Dots was -43 to -60 mV. C-Dots exhibited strong characteristics of UV newlineabsorption around 245nm and 300nm. Photoluminescence of C-dots was recorded for the newlineexcitation wavelength of 290nm. Highest intensity and waveleng