Far infrared radiated energy proficient rapid one pot green hydrolysis of waste watermelon peel: optimization and heterogeneous kinetics of glucose synthesis
For the first time, a one pot green hydrolysis of waste watermelon (Citrullus lanatus) peel (WWP) was optimized for a maximum glucose yield employing a heterogeneous Amberlyst 15 catalyst. The effects of energy proficient far infrared radiation (FIRR) on intensification of pretreatment and subsequent solvent free hydrolysis reactions in the one pot system have been maximized. The optimal process variables for pretreatment and consequent hydrolysis were 20 min and 10 min batch times, 70 degC and 60 degC reactor temperatures, and 5 and 10 (w/w) water to WWP ratios, respectively. Optimal 2.5 (w/w) NH4OH loading and 2.5 wt% catalyst concentration for pretreatment and hydrolysis under FIRR resulted in a maximum glucose yield (89.87 mol% which was superior to that obtained (59.86 mol% using a conventional thermal source. In comparison with pseudo homogeneous and Langmuir Hinshelwood models, the Eley Rideal model described the hydrolysis kinetics more accurately. Significantly, a higher hydrolysis activation energy (92.02 kJ mol 1) in the conventional system compared to the FIRR mode (activation energy, 59.69 kJ mol 1) clearly demonstrated the superior energy efficiency of the FIRR system. The energy proficient fast hydrolysis process is expected to be sustainable and applicable to similar lignocellulosic biomasses.