abstract
The study explores changes in biological conversion pathways of cheese whey due to supplementation of dark fermentation (DF), including additives such as fly ash (FA), biochar (BC), and geopolymer (GP) to improve the biohydrogen (bio-H2) production. Among these, FA (10 g/L) produced the highest bio-H2 giving 316.68 ml/g yield, showing an increase of 86 % compared to control. The promoting role of FA is attributed to strong buffering due to its high oxide and hydroxide contents, enhancing the system resistance against decrease in pH (drop from 6.5 to 4.79) compared to control that showed a significant drop in pH to 3.91 after 72 h. Detailed characterization of the additives using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray fluorescence (XRF), Brunauer, Emmett, Teller (BET) adsorption and analysis of metallic elements, electrical conductivity (EC), pH, volatile fatty acids (VFAs) and volatile solids (VS) removal, confirmed the release of Ca, Na, Mg, K, Fe, Mn, Ni, and Zn, leading to pH regulation and providing nutrients to promote metabolic activities of the microorganisms. Low bio-H2 production by the addition of GP is due to high EC (6.43 mS/m) achieved, leading to a shift in the conversion pathways from butyric acid production to acetate production.
keywords
BIO-HYDROGEN PRODUCTION; BIOMASS FLY-ASH; BIOHYDROGEN PRODUCTION; FOOD WASTE; ANAEROBIC-DIGESTION; INITIAL SUBSTRATE; OPTIMIZATION; BIOCHAR
subject category
Biochemistry & Molecular Biology; Chemistry; Polymer Science
authors
Nemati, B; Kamali, M; Aminabhavi, TM; Dewil, R; Tarelho, LAD; Alavi-Borazjani, SA; Gomes, HGMF; Costa, MEV; Capela, I
our authors
Helena Gomes
Junior Researcher
Maria Elisabete Jorge Vieira Costa
Collaborator
Mohammadreza Kamali
PhD StudentGroups
G2 - Photonic, Electronic and Magnetic Materials
G3 - Electrochemical Materials, Interfaces and Coatings
Projects
Collaboratory for Emerging Technologies, CoLab (EMERGING TECHNOLOGIES)
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
acknowledgements
The authors acknowledge Portuguese Foundation for Science and Technology (FCT) for financial support under the doctoral scholarship No. 2020.05304.BD for the first author. We also acknowledged the financial support of the FCT - Fundacao para a Ciencia e a Tecnologia I. P., under the project/grant UID/50006 + LA/P/0094/2020 (doi.org/10.54499/LA/P/0094/2020) . Thanks are also due to the financial support of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 (DOI 10.54499/UIDB/50011/2020) , UIDP/50011/2020 DOI 10. 54499/UIDP/50011/2020) & LA/P/0006/2020 (DOI 10.54499/LA/P/0006/2020) , financed by national funds through the FCT/MCTES (PIDDAC) . Thanks are also due to the financial support from the PDM program, KU Leuven.