Green synthesized Fe nanoparticle assisted biomass hydrolysis for bioenergy production: process parameters optimization through combined RSM and ANN based approach

Abstract

Bioenergy plays a crucial role in addressing the global energy crisis. The utilization of agricultural byproducts for biofuel production through fermentation is well-established. Among various pretreatment methods, breaking lignin and cellulose bonds under heat and pressure to release sugar moieties is the most predominant approach. This study focuses on enhancing sugar yield through the most economical, energy-efficient, and time-saving pretreatment of the highly underrated agricultural residue, cocoa pod shell (CPS), using green-synthesized FeO nanoparticles derived from CPS extract. The synthesized nanoparticles, ranging from 25 nm to 31 nm in size, exhibited an EDS spectrum confirming the atomic composition of C (30.01%), Fe (6.09%), O (59.76%), N (2.36%), P (0.79%), Cl (0.53%), and K (0.46%). FTIR analysis revealed the presence of O-H, C-H, C-Cl, and O = C = O stretching, indicating effective nanoparticle capping. The novel ex-situ hydrolysis process, coupled with induction heating, yielded 356.04 g/L of total sugars and 60.28 g/L of reducing sugars using 10% w/v biomass and 4% acid within just 30 min. RSM and ANN modeling were employed for process validation, yielding R² values of 0.91 and 0.92 for total and reducing sugars, respectively, while ANN modeling achieved R² values of 0.96 and 0.97. This energy-efficient hydrolysis process achieved a significant sugar yield in less time while requiring minimal raw material. It presents a scalable and reliable approach to the industries, providing a promising direction for biofuel production.