TY - JOUR
T1 - Valorization of humins from food waste biorefinery for synthesis of biochar-supported Lewis acid catalysts
AU - Xiong, Xinni
AU - Yu, Iris K.M.
AU - Dutta, Shanta
AU - Mašek, Ondřej
AU - Tsang, Daniel C.W.
N1 - Funding Information:
The authors appreciate the financial support from the Hong Kong International Airport Environmental Fund (Phase 2), Hong Kong Research Grants Council (PolyU 15217818 ), and PolyU Project of Strategic Importance. We also acknowledge the assistance of the University Research Facility on Chemical and Environmental Analysis (URFCE) of PolyU.
Publisher Copyright:
© 2021 Elsevier B.V.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/6/25
Y1 - 2021/6/25
N2 - To close the carbon loop of biomass waste valorization, it is imperative to utilize the unavoidable by-products such as humins, a carbonaceous residue with complex and heterogeneous composition. In this study, starch-rich rice waste was effectively converted into value-added chemicals (e.g., 5-hydroxymethylfurfural) under microwave heating at 160 °C using AlCl3 as the catalyst. The solid by-products, i.e., humins, were then valorized as a raw material for fabricating biochar-supported Lewis acid catalysts. The humins were collected and pretreated by AlCl3 as the impregnation agent, followed by carbonization. Detailed characterization revealed several Al–O species on the biochar surface plausibly in the amorphous state. The oxygen-containing functional groups of humins might serve as anchoring sites for the Al species during impregnation. The humins-derived biochars exhibited good catalytic activity toward glucose-to-fructose isomerization, a common biorefinery reaction catalyzed by Lewis acids. A fructose yield of up to 14 Cmol% could be achieved under microwave heating at 160 °C for 20 min in water as the greenest solvent. Such catalytic performance was comparable with the previously reported Al-based catalysts derived from wood waste and graphene/graphitic oxide. This study herein highlights humins as a low-cost alternative source of carbon for the preparation of renewable solid catalysts, proposing a novel practice for recycling by-products from food waste valorization to foster circular economy and sustainable development.
AB - To close the carbon loop of biomass waste valorization, it is imperative to utilize the unavoidable by-products such as humins, a carbonaceous residue with complex and heterogeneous composition. In this study, starch-rich rice waste was effectively converted into value-added chemicals (e.g., 5-hydroxymethylfurfural) under microwave heating at 160 °C using AlCl3 as the catalyst. The solid by-products, i.e., humins, were then valorized as a raw material for fabricating biochar-supported Lewis acid catalysts. The humins were collected and pretreated by AlCl3 as the impregnation agent, followed by carbonization. Detailed characterization revealed several Al–O species on the biochar surface plausibly in the amorphous state. The oxygen-containing functional groups of humins might serve as anchoring sites for the Al species during impregnation. The humins-derived biochars exhibited good catalytic activity toward glucose-to-fructose isomerization, a common biorefinery reaction catalyzed by Lewis acids. A fructose yield of up to 14 Cmol% could be achieved under microwave heating at 160 °C for 20 min in water as the greenest solvent. Such catalytic performance was comparable with the previously reported Al-based catalysts derived from wood waste and graphene/graphitic oxide. This study herein highlights humins as a low-cost alternative source of carbon for the preparation of renewable solid catalysts, proposing a novel practice for recycling by-products from food waste valorization to foster circular economy and sustainable development.
KW - Biomass valorization
KW - Engineered biochar
KW - Food waste recycling
KW - Glucose isomerization
KW - Sustainable biorefinery
KW - Waste management
UR - http://www.scopus.com/inward/record.url?scp=85101345691&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2021.145851
DO - 10.1016/j.scitotenv.2021.145851
M3 - Journal article
AN - SCOPUS:85101345691
SN - 0048-9697
VL - 775
JO - Science of the Total Environment
JF - Science of the Total Environment
M1 - 145851
ER -