Carbon-based nanomaterial from dragon-fruit (Hylocereus polyrhizus) peel waste as a liquid supplement for the growth of chili plant (Capsicum annuum)

Abstract Organic wastes such as fruit peels can be reduced and recycled into nanomaterials in liquid forms as plant supplement to overcome the ever-growing waste problem. This study is aimed at synthesizing and characterizing carbon-based nanomaterials (CbNMs) from dragon-fruit ( Hylocereus polyrhizus ) peel waste, and investigating their effects as a liquid supplement for the growth of chili plants ( Capsicum annuum ) based on the stem height, leaf width, and number of leaves. The CbNMs are synthesized via the two-step low heating (TSLH) method and characterized using ultraviolet-visible (UV-Vis) spectrophotometer, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, photoluminescence (PL), and particle size analyzer (PSA). The CbNMs are then applied as a liquid supplement for the chili plants. The results of the UV-Vis characterization show a shouldering peak at a wavelength of 270 nm. The XRD test shows that the CbNMs are amorphous. The FTIR test shows the presence of the C = C functional group, which indicates the carbon content of the CbNMs. The PL test shows an emission peak at a wavelength of 505 nm, which indicates cyan luminescence as confirmed by exposing a violet/UV laser pointer towards the CbNMs. The PSA test shows that the dominant particle size distribution of the CbNMs is 239.1 nm. Finally, the chili plants supplemented with the liquid CbNMs have better growth than those without the the application of the liquid CbNMs.