Synthesis of Cu-1,4-Benzene Dicarboxylate Metal-Organic Frameworks (Cu-BDC MOFs) from Plastic Waste and Its Application as Catalyst in Biodiesel Production

Abstract

The increasing of PET plastic waste causes various environmental problems because decomposing it is difficult to compose. This study aims to utilize PET plastic waste as a source of terephthalic acid organic linker in the solvothermal synthesis of Cu-1,4-Benzene Dicarboxylate metal-organic frameworks (Cu-BDC MOFs). Cu-BDC MOFs were characterized using FTIR, XRD, and SEM-EDX. The characterization results showed that the crystals of Cu-BDC MOFs had an irregular cubic morphology with an average crystal size of 67.96 nm. Furthermore, Cu-BDC MOFs were applied as catalysts for the esterification reaction to produce biodiesel from coconut oil. The conversion percentage of free fatty acids in the esterification process was 43.75 %, while in the transesterification process, it was 68.90 %. Analysis using GC-MS showed the presence of 8 peaks, with the largest percentage of areas identified as fatty acid methyl esters. The major components were methyl laurate (31.17 %), methyl myristate (18.77 %), methyl palmitate (12.50 %), methyl caprylate (10.76 %), methyl elaidate (10.07 %), methyl caprate (7.34 %), methyl stearate (5.67 %), and methyl linoleate (2.26 %). The quality of the biodiesel was tested, and the results were as follows: The density parameter was measured at 842.5 kg/m³, the viscosity measurement showed 2.9572 cSt, and the water content was found to be 0.09 %. Additionally, the acid number parameter was determined to be 0.2799 mg-KOH/g.

HIGHLIGHTS

• Cu-BDC MOFs are produced through the hydrolysis of PET waste using a solvothermal mixture of distilled water, ethanol, and DMF at 85 °C for 24 h.
• The micrograph of the synthesized Cu-BDC MOFs reveals a clustered topography of Cu-BDC MOFs crystals with irregular cubic (hexahedral) shapes.
• FTIR analysis of biodiesel displays distinctive peaks corresponding to the -C-H, -C=O, -CH₂, -CH₃, and -C-O functional groups.
• The GC-MS analysis of biodiesel from coconut oil shows the presence of 8 major peaks, namely methyl caprylate, methyl caprate, methyl laurate, methyl myristate, methyl palmitate, methyl linoleate, methyl elaidate, and methyl stearate, with the largest percent area.
• The quality test results of biodiesel indicate a density parameter of 842.5 kg/m³, a biodiesel viscosity measurement of 2.9572 cSt, a water content of 0.0898 %, and an acid number of 0.2799 mg-KOH/g.

GRAPHICAL ABSTRACT