Quality Improvement of Molasses by Activated Carbon Prepared from Fly Ash as Waste Driven out of Boiler in The Sugar Factory

Abstract

The sugar industry generates significant byproducts, particularly bagasse fly ash and molasses. This study added value to these residues by converting fly ash from boiler stacks (600–800°C) into activated carbon through physical activation at 700°C and 900°C for 0–200 min. The efficiency of the produced activated carbon was evaluated by measuring the residual weight after burning, iodine adsorption, and surface area. The results showed that the optimal condition was activation at 900°C for 80 minutes, which yielded a product with 83% residual weight, increased iodine adsorption capacity from 92 mg/g to 329 mg/g, and increased surface area from 16.2702±0.0177 m²/g to 80.2001±0.0375 m²/g. The produced activated carbon was tested for its efficiency in reducing the color value of molasses, studying factors of quantity, temperature, and time. The most suitable condition was found to be using 25% activated carbon by mass at 83°C for 68 minutes, which reduced the color value from 208,139±2335 ICU to 125,896 ICU, representing a 40% color reduction efficiency. Other molasses properties also improved: the concentration of soluble solids increased from 70.81±0.15% to 80.24% enhancing quality and reducing transportation costs, pH decreased from 4.79±0.01 to 4.49 while lower pH promoted sucrose hydrolysis beneficial for ethanol fermentation without affecting total sugar, total sugar content remained above the standard from 50.72±0.48% to 51.71% as a result of increased concentration, and turbidity decreased from 33.66±1.31 ICU to 25.35 ICU consistent with reduced sulfate ash (≤11%). This research demonstrates the potential for adding value to sugar industry byproducts and presents an environmentally friendly waste management approach by converting fly ash into efficient activated carbon for improving molasses properties.