TY  - JOUR
A1  - Reza, M. Toufiq
A1  - Rottler, Erwin
A1  - Herklotz, Laureen
A1  - Wirth, Benjamin
T1  - Hydrothermal carbonization (HTC) of wheat straw: Influence of feedwater pH prepared by acetic acid and potassium hydroxide
JF  - Bioresource technology : biomass, bioenergy, biowastes, conversion technologies, biotransformation, production technologies
N2  - In this study, influence of feedwater pH (2-12) was studied for hydrothermal carbonization (HTC) of wheat straw at 200 and 260 degrees C. Acetic acid and KOH were used as acidic and basic medium, respectively. Hydrochars were characterized by elemental and fiber analyses, SEM, surface area, pore volume and size, and ATR-FTIR, while HTC process liquids were analyzed by HPLC and GC. Both hydrochar and HTC process liquid qualities vary with feedwater pH. At acidic pH, cellulose and elemental carbon increase in hydrochar, while hemicellulose and pseudo-lignin decrease. Hydrochars produced at pH 2 feedwater has 2.7 times larger surface area than that produced at pH 12. It also has the largest pore volume (1.1 x 10(-1) ml g(-1)) and pore size (20.2 nm). Organic acids were increasing, while sugars were decreasing in case of basic feedwater, however, phenolic compounds were present only at 260 degrees C and their concentrations were increasing in basic feedwater. (C) 2015 Elsevier Ltd. All rights reserved.
KW  - Hydrothermal carbonization
KW  - HTC biochar
KW  - pH
KW  - Fiber analysis
KW  - Pore analysis
Y1  - 2015
U6  - https://doi.org/10.1016/j.biortech.2015.02.024
SN  - 0960-8524
SN  - 1873-2976
VL  - 182
SP  - 336
EP  - 344
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Reza, M. Toufiq
A1  - Rottler, Erwin
A1  - Tölle, Rainer
A1  - Werner, Maja
A1  - Ramm, Patrice
A1  - Mumme, Jan
T1  - Production, characterization, and biogas application of magnetic hydrochar from cellulose
JF  - Bioresource technology : biomass, bioenergy, biowastes, conversion technologies, biotransformation, production technologies
N2  - Hydrothermal carbonization (HTC) produces carbon-rich nano-micro size particles. In this study, magnetic hydrochar (MHC) was prepared from model compound cellulose by simply adding ferrites during HTC. The effects of ferrites on HTC were evaluated by characterizing solid MHC and corresponding process liquid. Additionally, magnetic stability of MHC was tested by magnetic susceptibility method. Finally, MHC was used as support media for anaerobic films in anaerobic digestion (AD). Ash-free mass yield was around 50% less in MHC than hydrochar produced without ferrites at any certain HTC reaction condition, where organic part of MHC is mainly carbon. In fact, amorphous hydrochar was growing on the surface of inorganic ferrites. MHC maintained magnetic susceptibility regardless of reaction time at reaction temperature 250 degrees C. Pronounced inhibitory effects of magnetic hydrochar occurred during start-up of AD but diminished with prolong AD times. Visible biofilms were observed on the MHC by laser scanning microscope after AD. (C) 2015 Elsevier Ltd. All rights reserved.
KW  - Cellulose
KW  - Hydrothermal carbonization
KW  - Magnetic hydrochar
KW  - Magnetic susceptibility
KW  - Anaerobic digestion
Y1  - 2015
U6  - https://doi.org/10.1016/j.biortech.2015.03.044
SN  - 0960-8524
SN  - 1873-2976
VL  - 186
SP  - 34
EP  - 43
PB  - Elsevier
CY  - Oxford
ER  -