Hydrothermal synthesis of spent coffee grounds carbon dots as photosynthesis enhancer on black behi pechay ( Brassica chinesis L.) / Rajie A. Medina, Crizzel Fe M. Dela Cruz, and Antonette G. Ramirez .--

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Medina, Rajie A [author ]

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TextPublication details: Manila: Technological University of the Philippines, 2024.Description: 103pages: 29cm. +1 CD-ROM (4 3/4in.)Content type:

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BTH RB 37 M43 2024

Dissertation note: College of Science .-- Bachelor of Applied Science in Laboratory Technology: Technological University of the Philippines, 2024. Summary: The researchers aimed to provide low-cost, environmentally friendly, and long-lasting ways of producing Carbon Quantum Dots (CQDs) by utilizing hydrothermal synthesis for the evaluation of their antimicrobial activities and optical properties. The leaf and bark extract of the mangrove (Rhizophora stylosa Griff.) plant was used in this study to produce carbon quantum dots using the hydrothermal method, and CQDs were characterized using UV-vis, FTIR, SEM, EDX, DLS, and an application for the optical property using Spectrofluorophotometer. The result revealed that the characterization demonstrates the effective synthesis of CQDs. UV-Vis spectroscopy occurred at wavelengths of 383 nm and 417 nm for the CQD-L and CQD-B series. Fourier Infrared spectroscopy revealed different peaks, including O-H stretching on Pure-B, Pure-L, CQD-B, and CQD-L, and N-H stretching on both CQD-B and CQD-L. Scanning Electron Microscopy (SEM) revealed a homogeneous and scattered appearance, with a smooth texture and an aggregated structure manifested as spherical-shaped, and also, rough, appearing round, clustered, and heterogeneous of CQD-L, and CQD-B respectively. Energy Dispersive X-ray Spectroscopy (EDX), for CQD-L had 56.6% content of carbon, whereas the CQD-B had a composition of carbon of 38.0%. Dynamic Light Scattering (DLS) hydrodynamic size yielded 749.7±51.11 d.nm and 542.5±72.48 d.nm, with polydispersity indexes of 0.4290.042 and 0.5560.102, and zeta potentials of -11.20.416 mV and -32.7-1.68Mv of CQD-L and CQD-B, respectively. Spectrofluorophotometer indicated a blue color for CQD-B and a red color for CQD-L, which are both parallel to the ultraviolet-visible spectrum. The phytochemical components connected with the mangrove (Rhizophora stylosa Griff.) plant have been successfully utilized to create Carbon Quantum Dots (CQDs). Only pure mangrove bark extract revealed antibacterial activity against S. aureus in an antimicrobial experiment, with an antimicrobial index (AI) of 0.8, but the remaining samples showed no antimicrobial action against E. coli, S. aureus, as well as C. albicans. As a result, for antibacterial tests, the pure bark was vulnerable to gram-positive bacteria. Keywords: Carbon Quantum Dots (CQDs), Hydrothermal method, Phytochemical components

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Holdings
Item type	Current library	Shelving location	Call number	Copy number	Status	Notes	Date due	Barcode
Bachelor's Thesis COS	TUP Manila Library	Thesis Section-2nd floor	BTH RB 37 M43 2024 (Browse shelf(Opens below))	c.1.	Not for loan	For library use only		BTH0004995

Thesis (undergraduate)

College of Science .-- Bachelor of Applied Science in Laboratory Technology: Technological University of the Philippines, 2024.

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The researchers aimed to provide low-cost, environmentally friendly, and long-lasting
ways of producing Carbon Quantum Dots (CQDs) by utilizing hydrothermal synthesis for
the evaluation of their antimicrobial activities and optical properties. The leaf and bark
extract of the mangrove (Rhizophora stylosa Griff.) plant was used in this study to produce
carbon quantum dots using the hydrothermal method, and CQDs were characterized using
UV-vis, FTIR, SEM, EDX, DLS, and an application for the optical property using
Spectrofluorophotometer. The result revealed that the characterization demonstrates the
effective synthesis of CQDs. UV-Vis spectroscopy occurred at wavelengths of 383 nm and
417 nm for the CQD-L and CQD-B series. Fourier Infrared spectroscopy revealed different
peaks, including O-H stretching on Pure-B, Pure-L, CQD-B, and CQD-L, and N-H
stretching on both CQD-B and CQD-L. Scanning Electron Microscopy (SEM) revealed a
homogeneous and scattered appearance, with a smooth texture and an aggregated structure
manifested as spherical-shaped, and also, rough, appearing round, clustered, and
heterogeneous of CQD-L, and CQD-B respectively. Energy Dispersive X-ray
Spectroscopy (EDX), for CQD-L had 56.6% content of carbon, whereas the CQD-B had a
composition of carbon of 38.0%. Dynamic Light Scattering (DLS) hydrodynamic size
yielded 749.7±51.11 d.nm and 542.5±72.48 d.nm, with polydispersity indexes of
0.4290.042 and 0.5560.102, and zeta potentials of -11.20.416 mV and -32.7-1.68Mv of
CQD-L and CQD-B, respectively. Spectrofluorophotometer indicated a blue color for
CQD-B and a red color for CQD-L, which are both parallel to the ultraviolet-visible
spectrum. The phytochemical components connected with the mangrove (Rhizophora
stylosa Griff.) plant have been successfully utilized to create Carbon Quantum Dots
(CQDs). Only pure mangrove bark extract revealed antibacterial activity against S. aureus
in an antimicrobial experiment, with an antimicrobial index (AI) of 0.8, but the remaining
samples showed no antimicrobial action against E. coli, S. aureus, as well as C. albicans.
As a result, for antibacterial tests, the pure bark was vulnerable to gram-positive bacteria.

Keywords: Carbon Quantum Dots (CQDs), Hydrothermal method, Phytochemical
components

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