This study provides insight into the decolorization strategy for crude glycerol obtained from biodiesel production using waste cooking oil as raw material. A sequential procedure that includes physico-chemical treatment and adsorption using activated carbon from oil palm biomass was investigated. The results evidenced decolorization and enrichment of glycerol go hand in hand during the treatment, achieving >89% color removal and > 98% increase in glycerol content, turning the glycerol into a clear (colorless) solution. This is attributed to the complete removal of methanol, free fatty acids, and triglycerides, as well as 85% removal of water, and 93% removal of potassium. Properties of the resultant glycerol met the quality standard of BS 2621:1979. The economic aspects of the proposed methods are examined to fully construct a predesign budgetary estimation according to chemical engineering principles. The starting capital is proportionate to the number of physical assets to acquire where both entail a considerable cost at USD 13,200. Having the benefit of sizeable scale production, it reasonably reduces the operating cost per unit product. As productivity sets at 33 m3 per annum, the annual operating costs amount to USD 79,902 in glycerol decolorization. This is translatable to USD 5.38 per liter glycerol, which is ~69% lower compared to using commercial activated carbon.
This study investigated an innovative strategy of incorporating surfactants into alkaline-catalyzed glycerol pretreatment and enzymatic hydrolysis to improve lignocellulosic biomass (LCB) conversion efficiency. Results revealed that adding 40 mg/g PEG 4000 to the pretreatment at 195 °C obtained the highest glucose yield (84.6%). This yield was comparable to that achieved without surfactants at a higher temperature (240 °C), indicating a reduction of 18.8% in the required heat input. Subsequently, Triton X-100 addition during enzymatic hydrolysis of PEG 4000-assisted pretreated substrate increased glucose yields to 92.1% at 6 FPU/g enzyme loading. High-solid fed-batch semi-simultaneous saccharification and co-fermentation using this dual surfactant strategy gave 56.4 g/L ethanol and a positive net energy gain of 1.4 MJ/kg. Significantly, dual assistance with surfactants rendered 56.3% enzyme cost savings compared to controls without surfactants. Therefore, the proposed surfactant dual-assisted promising approach opens the gateway to economically viable enzyme-mediated LCB biorefinery.