Enzyme-assisted hydrothermal treatment of food waste for co-production of hydrochar and bio-oil.
Food waste was subjected to enzymatic hydrolysis prior to hydrothermal treatment to produce hydrochars and bio-oil. Pre-treatment of food waste with an enzyme ratio of 1:2:1 (carbohydrase:protease:lipase) proved to be effective in converting food waste to the two products with improved yields. The carbon contents and calorific values ranged from 43.7% to 65.4% and 17.4 to 26.9 MJ/kg for the hydrochars obtained with the enzyme-assisted pre-treatment, respectively while they varied from 38.2% to 53.5% and 15.0 to 21.7 MJ/kg, respectively for the hydrochars obtained with no pre-treatment. Moreover, the formation of carbonaceous microspheres with low concentrations of inorganic elements and diverse surface functional groups was observed in the case of enzyme-assisted food waste hydrochars. The enzymatic pre-treatment also facilitated the formation of the bio-oil with a narrow distribution of organic compounds and with the highest yield obtained at 350 °C.
Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Republic of Singapore.
Rajni
R
Kaushik
Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Republic of Singapore.
Ganesh K
GK
Parshetti
Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Republic of Singapore.
Zhengang
Z
Liu
Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Republic of Singapore. Electronic address: ceerbala@nus.edu.sg.
Rajasekhar
R
Balasubramanian
D002606:Charcoal / Q000737:chemistry*; D004798:Enzymes / Q000378:metabolism*; D005502:Food; D006868:Hydrolysis / Q000187:drug effects; D009821:Oils / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D012037:Refuse Disposal / Q000379:methods*; D012996:Solutions; D013696:Temperature; D013997:Time Factors; D014866:Waste Products; D014867:Water / Q000494:pharmacology*
D004798:Enzymes; D009821:Oils; D012996:Solutions; D014866:Waste Products; C540010:biochar; D014867:Water; D002606:Charcoal
Bio-oil; Enzymatic hydrolysis; Food waste; Hydrochar; Hydrothermal carbonization