Optimal condition of fenton's reagent to enhance the alcohol production from palm oil mill effluent (POME)

Abstract

Application of Fenton's reaction for a proper hydrolysis step is an essential and important step in obtaining a higher level of readily biodegradable sugars from palm oil mill effluent (POME) for improving the alcohol production by using immobilized Clostridium acetobutylicum. The objective of this research was, therefore, to investigate the optimum condition of Fenton's reaction in terms of COD: H 2 O 2 ratios (w/w) and H 2 O 2 : Fe 2+ ratios (molar ratio) used to oxidize carbohydrate and high molecular organic compounds into simple sugars, which are further fermented into alcohol. The experiments were carried out at H 2 O 2 : Fe 2+ ratios (molar ratios) of 5, 10, 20, 30 and 40 and the COD: H 2 O 2 ratios (w/w) of 50, 70, 100 and 130 (initial COD about 50,000 mg/L). The total sugar concentrations and organic compounds biodegradability (BOD 5 /COD ratios) were also used for investigating suitable conditions for Fenton's reaction. The concentration of Fenton's reagent at H 2 O 2 :Fe 2+ and COD:H 2 O 2 ratio of 20 and 130 was identified as the optimum operating condition for the highest simple sugars of about 0.865% and BOD 5 /COD ratios of 0.539. The alcohol productions were carried out in the continuous stirred tank reactors (CSTR) under an anaerobic continuous immobilization system. At a hydraulic retention time of 12 hours and POME pH of 4.8, the maximum total ABE concentration of 495 mg/L and the ABE yield of 0.236 grams of ABE produced/ gram of reducing sugars were achieved at the mixed polyvinyl alcohol (PVA) and palm oil ash (POA) ratio of 10: 3.