Glucose hydrochar consists of linked phenol, furan, arene, alkyl, and ketone structures revealed by advanced solid-state nuclear magnetic resonance.

The molecular structure of hydrochars produced from C-enriched glucose under various conditions has been elucidated based on advanced one- and two-dimensional (2D) H-C and C-C solid-state nuclear magnetic resonance (NMR) with spectral editing. Regardless of synthesis conditions, hydrochars consist mostly of oxygen-substituted arene rings (including diphenols) and furans connected by alkyl linkers rich in ketones. Cross-linking nonprotonated and methyne (C-H) alkyl carbons have been identified through spectrally edited 2D NMR.

Measurement of the reaction enthalpy of CO in aqueous solutions with thermographic and gravimetric methods.

In this work, a new concept for the approximate determination of the reaction enthalpy of the reaction between CO and monoethanolamine (MEA) in aqueous solution was developed. For this purpose, a CO gas stream was flowed into aqueous MEA solutions with different concentrations of 1 wt%, 2.5 wt% and 7.

Evaluation of the Char Formation During the Hydrothermal Treatment of Wooden Balls.

With wooden balls, a visualization of the hydrothermal carbonization to show the progress of the conversion to char is presented. In the present study, the balls represent the particles of biomass to investigate the differences in conversion outside and inside of biomass particles, during hydrothermal carbonization. A special focus is on hydrochar and pyrochar formation.

Multivariate and multi-interface insights into carbon and energy recovery and conversion characteristics of hydrothermal carbonization of biomass waste from duck farm.

High lipid, high nitrogen duck manure (DM) with high lipid, high lignocellulosic litter materials (LM) are the main wet biomass wastes from duck farms and both are naturally abundant carbon resources. The synthesis of duck farming biomass waste into carbon-rich materials for high value utilization by hydrothermal carbonization (HTC), which can directly treat wet biomass, has not been investigated. In this study, the physicochemical properties of hydrochar derived from co-HTC of DM and LM and its carbon and energy recovery patterns were systematically investigated under multivariate conditions of raw materials ratios, solids contents, temperatures and residence times.

Challenges of Green Production of 2,5-Furandicarboxylic Acid from Bio-Derived 5-Hydroxymethylfurfural: Overcoming Deactivation by Concomitant Amino Acids.

The oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is highly attractive as FDCA is considered as substitute for the petrochemically derived terephthalic acid. There are only few reports on the direct use of unrefined HMF solutions from biomass resources and the influence of remaining constituents on the catalytic processes. In this work, the oxidation of HMF in a solution as obtained from hydrolysis and dehydration of saccharides in chicory roots was investigated without intermediate purification steps.

Effect of residence time during hydrothermal carbonization of biogas digestate on the combustion characteristics of hydrochar and the biogas production of process water.

The biogas digestate from anaerobic digestion of cow manure and energy crops was treated by hydrothermal carbonization (HTC) at 210 °C for 0.5 to 5 h to understand the effect of HTC residence time on the combustion characteristics of hydrochar and the biogas production of process water. The increase in HTC residence time slightly reduced the higher heating values (16.

Hydrothermal Conversion of Spent Sugar Beets into High-Value Platform Molecules.

The growing importance of bio-based products, combined with the desire to decrease the production of wastes, boosts the necessity to use wastes as raw materials for bio-based products. A waste material with a large potential is spent sugar beets, which are mainly used as animal feeds or fertilizers. After hydrothermal treatment, the produced chars exhibited an H/C ratio of 1.

Nitrogen-Containing Hydrochar: The Influence of Nitrogen-Containing Compounds on the Hydrochar Formation.

Hydrothermal carbonization (HTC) of fructose and urea containing solutions was conducted at 180 °C to study the influence of nitrogen-containing compounds on conversion and product properties. The concentration of fructose was fixed, while the concentration of urea was gradually increased to study its influence on the formation of nitrogen-containing hydrochar (N-HC). The degradation of urea has an important influence on the HTC of fructose.

Hydrothermal carbonization coupled with anaerobic digestion for the valorization of the organic fraction of municipal solid waste.

Hydrothermal carbonization (HTC) was evaluated as a promising treatment to enhance the biomethane potential during anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW). The OFMSW was carbonized at different conditions and HTC products were tested for biomethane potential into AD. Results proved that the use of HTC liquid and slurry into AD led to an increase in biomethane production up to 37% and 363%, respectively, compared to OFMSW.

Structural Effects of Cellulose on Hydrolysis and Carbonization Behavior during Hydrothermal Treatment.

This study aims to investigate how the morphology of cellulose influences the hydrolysis and carbonization during hydrothermal treatment at temperatures between 180 and 240 °C. The morphology of cellulose, especially different crystallinities and degrees of polymerization, is represented by microcrystalline cellulose and α-cellulose. Kinetic analysis is considered a tool to allow the determination of the mechanisms of the two types of cellulose during the hydrothermal process.

Porous carbons derived from hydrothermally treated biogas digestate.

Porous carbons from digestate-derived hydrochar were produced, characterized and their performance to reclaim phosphate from water was evaluated as a preliminary approach to demonstrate their practical application. In a first step, the digestate was converted into hydrochars through hydrothermal carbonization by using two different pH conditions: 8.3 (native conditions) and 3.

Towards the Properties of Different Biomass-Derived Proteins via Various Extraction Methods.

This study selected three representative protein-rich biomass-brewer's spent grain (BSG), pasture grass (PG), and cyanobacteria (; AP) for protein extraction with different extraction methods (alkaline treatment, aqueous extraction, and subcritical water extraction). The yield, purity, molecular weight, oil-water interfacial tension, and thermal stability of the obtained proteins derived from different biomass and extraction methods were comprehensively characterized and compared. In the view of protein yield and purity, alkaline treatment was found optimal for BSG (21.

Steam Explosion Conditions Highly Influence the Biogas Yield of Rice Straw.

Straws are agricultural residues that can be used to produce biomethane by anaerobic digestion. The methane yield of rice straw is lower than other straws. Steam explosion was investigated as a pretreatment to increase methane production.

Hydrothermal carbonization of biogas digestate: Effect of digestate origin and process conditions.

Hydrothermal carbonization (HTC) solids were produced in a 250-ml batch reactor from three different digestates at varying temperatures (170, 190, 210, 230, and 250 °C) and 2 and 5 h reaction time. Three potential feedstocks of biogas plants were tested: organic household waste, cow manure, and energy crops. The proximate composition, elemental composition, heating values, and thermal stability of the HTC solids were characterized.

Phosphorus recovered from digestate by hydrothermal processes with struvite crystallization and its potential as a fertilizer.

Phosphorus (P) recovery from digestate has attracted considerable interest. In this study, hydrothermal processes in combination with struvite crystallization were performed to promote P solubilization and capture from digestate; its potential as a phosphate-based fertilizer was also investigated. Hydrothermal treatment with HCl and HO showed good results for the solubilization of organic and slightly soluble P, and achieved the lowest input energy need (768 kWhkg).

Influence of the pH Value on the Hydrothermal Degradation of Fructose.

The hydrothermal treatment of sugars features a promising technology for the production of fine and platform chemicals from renewable resources. In this work the hydrothermal decomposition of fructose was studied in a buffered medium at a pH range between 2.2 and 8.

Experimental and thermodynamic studies of phosphate behavior during the hydrothermal carbonization of sewage sludge.

Recovered phosphate from sewage sludge is becoming a key product in the fertilizer market. This study investigates the fate of phosphate during the hydrothermal carbonization of digested sewage sludge to support the development of an economic and sustainable solution for dealing with sewage sludge for phosphate recovery. The solid products from the hydrothermal carbonization of digested sewage sludge in a batch reactor (180, 220, and 260 °C; 1, 2, and 4 h; digested sewage sludge-to-water ratios of 0.

Conductive Carbon Materials from the Hydrothermal Carbonization of Vineyard Residues for the Application in Electrochemical Double-Layer Capacitors (EDLCs) and Direct Carbon Fuel Cells (DCFCs).

This study investigates the production of bio-based carbon materials for energy storage and conversion devices based on two different vineyard residues (pruning, pomace) and cellulose as a model biomass. Three different char categories were produced via pyrolysis at 900 °C for 2 h (biochars, BC), hydrothermal carbonization (HTC) (at 220, 240 or 260 °C) with different reaction times (60, 120 or 300 min) (hydrochars, HC), or HTC plus pyrolysis (pyrolyzed hydrochars, PHC). Physicochemical, structural, and electrical properties of the chars were assessed by elemental and proximate analysis, gas adsorption surface analysis with N and CO, compression ratio, bulk density, and electrical conductivity (EC) measurements.

Hydrothermal carbonization of dry toilet residues as an added-value strategy - Investigation of process parameters.

Human faeces from a dry toilet are converted via hydrothermal carbonization to obtain a sterilized carbonaceous material. During this process the original material undergoes consecutively hydrolysis, water elimination and polymerization reactions. Consequently, the oxygen content is reduced, leading to a material with a better dewaterability and an attractive higher heating value (HHV = 22-28 MJ kg).

One stage olive mill waste streams valorisation via hydrothermal carbonisation.

An olive waste stream mixture, coming from a three phase-continuous centrifugation olive oil mill industry, with a typical wet basis mass composition of olive pulp 39 wt%, kernels 5 wt% and olive mill waste water 56 wt%, was subjected to hydrothermal carbonisation (HTC) at 180, 220 and 250 °C for a 3-hour residence time in a 2-litre stainless steel electrically heated batch reactor. The raw feedstock and corresponding hydrochars were characterised in terms of proximate and ultimate analyses, higher heating values and energy properties. Results showed an increase in carbonisation of samples with increasing HTC severity and an energy densification ratio up to 142% (at 250 °C).

Biobased Functional Carbon Materials: Production, Characterization, and Applications-A Review.

Even though research on porous carbon materials from biomass dates back to at least hundred years, it is still an extremely relevant topic. These materials can be found in applications that range from those that are widely known, such as water treatment, to others that are newer and indispensable for the transition towards environmentally friendly technologies, such as lithium- and sodium-ion batteries. This review summarizes some of the most relevant research that has been published concerning production technologies, insights on the chemical reaction mechanisms, characterization techniques, as well as some examples of the applications and the properties that the carbon materials must fulfil to be used in those applications.

Microwave digestion-assisted HFO/biochar adsorption to recover phosphorus from swine manure.

A sustainable management option for dealing with waste straw is to pyrolyze it to create biochar, which can then be used as a sorbent in pollution treatments, such as the recovery of phosphorus (P) from swine manure. However, the inability to directly capture soluble organic P (OP) and sparingly soluble P and the low selectivity of biochar remain key issues in this process. To overcome these, we investigated a microwave (MW) digestion pretreatment with a HFO/biochar adsorption process.

Polyethylene imine modified hydrochar adsorption for chromium (VI) and nickel (II) removal from aqueous solution.

An adsorbent hydrochar was synthesized from corn cobs and modified with polyethylene imine (PEI). The hydrochars before and after modification were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis. FTIR and XPS revealed that the PEI was grafted onto the hydrochar via ether and imine bonds formed with glutaraldehyde.

Effects of different biofilm carriers on biogas production during anaerobic digestion of corn straw.

This study investigated the performance of anaerobic digestion systems using four types of fibrous biofilm carriers, a polypropylene, a polyester, a polyamide, and a polyurethane fiber material. The biogas and methane production, pH, chemical oxygen demand, total solids content, volatile solids content, residual coenzyme F, and microbial community compositions were determined during the experimental runs. Furthermore, scanning electron microscopy was employed to identify the microbial consortium and examine their attachment onto the surface of the four fibrous biofilm carriers.

Wastewater treatment--adsorption of organic micropollutants on activated HTC-carbon derived from sewage sludge.

Organic micropollutants (MPs), in particular xenobiotics and their transformation products, have been detected in the aquatic environment and the main sources of these MPs are wastewater treatment plants. Therefore, an additional cleaning step is necessary. The use of activated carbon (AC) is one approach to providing this additional cleaning.