Toxicity evaluation of process water from hydrothermal carbonization of sugarcane industry by-products

Abstract

Hydrothermal carbonization (HTC) is a thermochemical process carried out in an aqueous medium. It is capable of converting biomass into a solid, carbon-rich material (hydrochar), and producing a liquid phase (process water) which contains the unreactive feedstock and/or chemical intermediates from the carbonization reaction. The aim of this study was to evaluate the characteristics of process water generated by HTC from vinasse and sugarcane bagasse produced by sugarcane industry and to evaluate its toxicity to both marine (using Artemia salina as a model organism) and the terrestrial environment (through seed germination studies of maize, lettuce, and tomato). The experiments showed that concentrated process water completely inhibited germination of maize, lettuce, and tomato seeds. On the other hand, diluted process water was able to stimulate seedlings of maize and tomato and enhance root and shoot growth. For Artemia, the LC indicated that the process water is practically non-toxic; however, morphological changes, especially damages to the digestive tube and antennas of Artemia, were observed for the concentration of 1000 mg C L.

Process Waters from Hydrothermal Carbonization of Sludge: Characteristics and Possible Valorization Pathways

“…However, it has also been reported that HTC process waters contain some compounds, such as phenols, organic acids and furans, which may, on the other hand, have some toxic effects on the development of plants. Recently, the toxicity of HTC process waters from sugarcane bagasse and vinasse to both the marine and terrestrial environment was evaluated by Fregolente et al [ 118 ]. The authors showed that the terrestrial inhibition and the germination delay is species-dependent: concentrated process waters inhibited the seed germination process of maize, lettuce and tomato seeds.…”

Biochar as an Eco-Friendly and Economical Adsorbent for the Removal of Colorants (Dyes) from Aqueous Environment: A Review

“…• C and extremely high pressures of 10 bars or more [62][63][64][65][66]. At such high temperatures and pressure, the pH of the solution decreases due to the increase in production of oxonium ion.…”

“…The biochar produced from regular pyrolysis varies in many aspects from the biochar produced by hydrothermal carbonization; hence, the product obtained from hydrothermal carbonization is called as hydrochar rather than biochar. Hydrochar and biochar vary in properties and conditions in which they are prepared [68], but they are essentially composed of the same chemical constituents and are prepared from the same raw material [64,65].…”

Insights on Molecular Characteristics of Hydrochars by 13C-NMR and Off-Line TMAH-GC/MS and Assessment of Their Potential Use as Plant Growth Promoters

“…The solid material from pyrolysis is called biochar while the solid product generated in HTC is defined as hydrochar. The HTC process also generates a liquid product named process water, which has been used as fertilizer [ 1 , 4 ] or recycled in new HTC process (recirculation) [ 5 , 6 , 7 ]. The solid products from HTC and pyrolysis can be destined for different purposes as solid fuel [ 8 , 9 ], adsorbents [ 10 ], catalysis [ 11 ], batteries and supercapacitors [ 12 ], among others [ 2 , 13 ].…”