Page 25 - AJWEP-22-5

Heterogeneous catalysts for biodiesel production

processed at 500°C retain more organic content (59.57%
References 245 246 247 194 248 249 250 251 252 216 247 253 254 oxygen). The presence of multiple active components
(potassium, calcium, and magnesium) in catalysts, such
as S. indicum (potassium: 29.64%, calcium: 33.80%,
and magnesium: 9.68%) suggests potential synergistic
Oxygen 19.88 - - 35.34 - 41.55 - 37.20 46.74 36.72 59.57 - 37.00 effects in catalytic applications. Carbon content varies

substantially (1.91 – 29.16%) in Citrus sinensis peel and
pawpaw peel, showing higher values, which may affect
Carbon - - - 12.02 - 9.18 - - 16.71 29.16 12.19 - 4.07 the surface area and porosity. The data underscores
the importance of pre-cursor selection and processing
conditions in tailoring catalyst composition for specific
Phosphorus - - - - - 1.91 - 0.64 3.04 1.19 - - catalysts demonstrate the potential for sustainable catalyst
biodiesel production requirements. These waste-derived
development by valorizing agricultural byproducts.

Silicon - - 3.54 3.87 10.03 3.06 3.79 - 8.51 0.00 - 11.32 4.33 4.3. Hydrothermal process
One popular technique for preparing catalysts is the
hydrothermal process. To produce differences in crystal
Composition (%) Aluminum - - 0.94 - - - 0.25 - 0.44 - - - - example, zinc oxide nanorods with a mean width of
shape, the solution must be heated and mixed. As an
38 nm and a length of 230 nm are produced when a zinc
nitrate solution is heated. Materials that are normally
Table 7. Composition of various solid base catalysts derived from waste biomass
insoluble under normal circumstances can be dissolved
Magnesium 4.66 4.41 4.63 3.61 4.77 2.02 4.52 1.30 0.86 1.00 5.92 9.68 2.61 and recovered using a process called hydrothermal
synthesis. Quick processing, excellent yields,
255
affordability, and ecological responsibility are just a
few of the benefits that make this approach popular.
256
Calcium 7.09 21.08 18.02 - 30.28 2.71 7.4 5.01 5.13 2.86 10.09 33.80 2.85 Because of the increased surface contact between the
solvent and the soluble particles; the final product
of hydrothermal treatment closely resembles the
Potassium 68.37 56.71 65.45 45.16 53.25 36.54 20.2 8.95 19.05 23.89 9.87 29.64 49.13 original stoichiometric composition. Greater reaction
temperatures promote mass transfer and molecular
diffusion rates by decreasing the solvent’s viscosity
and increasing particle solubility. This produces
257
Sodium - 14.78 0.70 - 1.67 1.85 0.4 - - 0.00 - 1.42 - extremely crystalline nanoparticles that are very pure
and have a limited size distribution, frequently obviating
the need for further calcination. Particle size, shape,
Calcination condition 700°C, 4h 700°C, 4h 900°C, 3h 500°C, 4h 700°C, 4h 700°C, 3h 700°C, 4h Burnt 550°C, 2h 600°C, 4h 500°C, 2h 550°C, 2h 550°C, 2h crystal structure, pressure, and reaction duration are just
a few of the catalyst parameters that may be precisely
controlled using this method.
258
A number of researchers have effectively
manufactured catalysts using the hydrothermal
technique. Continuous hydrothermal synthesis, for
instance, has been used to create nanoparticles modified
by oleic and decanoic acids. This approach has produced
Source of catalyst Musa spp. peduncle Carica papaya stem Sweet potato leaves Ripe-unripe plantain ash Tectona grandis leaves Potato peel Poovan banana pseudostem Citrus sinensis peel Heteropanax fragrans Pawpaw peel Moringa leaves Sesamum indicum ACP-550 positive results for other researchers. 259-262

4.4. Impregnation process
Heterogeneous catalysts can be prepared through
the impregnation process, which involves applying

Volume 22 Issue 5 (2025) 19 a solution to a catalyst support that contains metal.
doi: 10.36922/AJWEP025130095