TY - JOUR

T1 - Upcycling Waste to Wealth

T2 - CuO-SiO₂/reduced graphene nanocomposite from pomegranate peels for one-pot low-temperature conversion of waste oils into valuable fatty acid monomers

AU - Mahran, Shahenda

AU - Centeno, Maria

AU - Attia, Attia

AU - Saha, Basu

PY - 2025/8/27

Y1 - 2025/8/27

N2 - The utilisation of heterogeneous catalysts in producing fatty acid monomers can minimise the separation cost and hence reduce the price of the fatty acid monomers. This study reports for the first time a novel, environmentally benign, highly active copper oxide-silica oxide/reduced graphene oxide (CuO-SiO2/RGO), heterogeneous nano-catalyst derived from waste pomegranate peels, for the one-pot, low-temperature synthesis of fatty acid monomers from high-acid-value waste vegetable oil (WVO). The synthesised nano-catalyst was extensively characterised using XRD, FT-IR, TEM, SEM, EDX and TGA-DTA. Further, it was utilised to synthesise fatty acid-rich oleic phenoxypropyl acrylate (OPA) monomer from high acid value WVO via a single-step reaction. The process parameters for the synthesis of OPA monomer using CuO-SiO2/RGO catalyst have been optimised using response surface methodology (RSM) and found to be 8.5:1 reactant molar ratio, 3.5% (w/w) catalyst loading, 54 ºC temperature, and 9.5 h reaction time, where the highest OPA monomer yield was 95.73% under optimum conditions. The CuO-SiO2/RGO exhibited stable catalytic performance after regeneration with an OPA yield of 93.1±0.37% after five consecutive runs. The plausible reaction mechanism unveiled that the direct synthesis of OPA monomer from high acid value WVO occurred through both transesterification and esterification reactions simultaneously on the surface of CuO and SiO2 catalyst supported on RGO sheets. The adaptation of waste pomegranate peels into a high-value CuO-SiO2/RGO nano-catalyst offers a new direction for clean, one-pot and low-temperature production of sustainable fatty acid monomers from high-acid-value WVO.

AB - The utilisation of heterogeneous catalysts in producing fatty acid monomers can minimise the separation cost and hence reduce the price of the fatty acid monomers. This study reports for the first time a novel, environmentally benign, highly active copper oxide-silica oxide/reduced graphene oxide (CuO-SiO2/RGO), heterogeneous nano-catalyst derived from waste pomegranate peels, for the one-pot, low-temperature synthesis of fatty acid monomers from high-acid-value waste vegetable oil (WVO). The synthesised nano-catalyst was extensively characterised using XRD, FT-IR, TEM, SEM, EDX and TGA-DTA. Further, it was utilised to synthesise fatty acid-rich oleic phenoxypropyl acrylate (OPA) monomer from high acid value WVO via a single-step reaction. The process parameters for the synthesis of OPA monomer using CuO-SiO2/RGO catalyst have been optimised using response surface methodology (RSM) and found to be 8.5:1 reactant molar ratio, 3.5% (w/w) catalyst loading, 54 ºC temperature, and 9.5 h reaction time, where the highest OPA monomer yield was 95.73% under optimum conditions. The CuO-SiO2/RGO exhibited stable catalytic performance after regeneration with an OPA yield of 93.1±0.37% after five consecutive runs. The plausible reaction mechanism unveiled that the direct synthesis of OPA monomer from high acid value WVO occurred through both transesterification and esterification reactions simultaneously on the surface of CuO and SiO2 catalyst supported on RGO sheets. The adaptation of waste pomegranate peels into a high-value CuO-SiO2/RGO nano-catalyst offers a new direction for clean, one-pot and low-temperature production of sustainable fatty acid monomers from high-acid-value WVO.

KW - Waste vegetable oil valorisation

KW - Response surface methodology

KW - green nano-catalyst

KW - fatty acid-rich monomer

KW - waste pomegranate peels

U2 - 10.1016/j.fuproc.2025.108314

DO - 10.1016/j.fuproc.2025.108314

M3 - Journal article

VL - 277

JO - Fuel Processing Technology

JF - Fuel Processing Technology

SN - 0378-3820

M1 - 108314

ER -