Water Hydrolysis Research Articles

Reaction pathways and kinetics of N-acetyl-d-glucosamine hydrolysis in sub- and supercritical water

Subcritical and supercritical water hydrolysis of N-acetyl-d-glucosamine (NAG) to value-added chemicals has been studied in detail.

Subcritical Water Process for Reducing Sugar Production from Biomass: Optimization and Kinetics

The competitive reactions of lignocellulose hydrolysis and monosaccharide degradation in the subcritical water (SCW) hydrolysis of coconut husk were investigated to optimize the reducing sugar yield. Optimization analysis was performed by response surface methodology (RSM) and kinetics studies. Parameters of process optimization were varied at 130-170 °C for 15-45 min. The reducing sugars were measured using the Dinitro salicylic acid method. The sugar yield increased when the temperature increased from 130 °C to 170 °C. The highest reduction sugar yield of 4.946 g/L was obtained at 183.6 °C for 4.8 min and 23.4 liquid/solid ratio (LSR). Kinetics studies were carried out at temperature variations of 150, 170, and 190 °C and pressures of 60, 80, and 100 bar for 5 to 60 min. The yield of reducing sugar decreased with increasing temperature. The kinetic model 2B is the best method to explain the competitive reaction kinetics of coconut husk hydrolysis. This research is an innovation to increase the reducing sugar to make the process more commercially viable. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Subcritical water hydrolysis of industrial cake leftovers for sugar production

Subcritical water hydrolysis of industrial cake leftovers for sugar production

Degradation of Plasticised Poly(lactide) Composites with Nanofibrillated Cellulose in Different Hydrothermal Environments

In this study, bionanocomposite films based on poly(lactide) (PLA) plasticised with poly(ethylene glycol) (PEG) (7.5 wt%) and reinforced with various contents of nanofibrillated cellulose (NFC) (1, 3, 5 wt%) were prepared. The hydrothermal degradation was investigated through immersion in several aqueous environments at temperatures of 8, 23, 58, and 70 °C as a function of time (7, 15, 30, 60, 90 days). The effect of water immersion on the physicochemical properties of the materials was assessed by monitoring the changes in the morphology, thermo-oxidative stability, thermal properties, and molar mass through field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and gel permeation chromatography (GPC). The hydrothermal degradation behaviour was not critically affected regardless of the nanofibrillated cellulose content. All the materials revealed certain integrity towards water immersion and hydrolysis effects at low temperatures (8 and 23 °C). The low hydrothermal degradation may be an advantage for using these PLA biocomposites in contact with water at ambient temperatures and limited exposure times. On the other hand, immersion in water at higher temperatures above the glass transition (58 and 70 °C), leads to a drastic deterioration of the properties of these PLA-based materials, in particular to the reduction of the molar mass and the disintegration into small pieces. This hydrothermal degradation behaviour can be considered a feasible option for the waste management of PLA/PEG/NFC bionanocomposites by deposition in hot aqueous environments.

Subcritical water pretreatment enhanced methane-rich biogas production from the anaerobic digestion of brewer’s spent grains

ABSTRACT This study evaluated the effectiveness of a semi-continuous flow-through subcritical water hydrolysis (SWH) pretreatment of brewer’s spent grains (BSG) for subsequent application in the anaerobic digestion (AD) process. BSG pretreatment was conducted at 160 °C and 15 MPa with a flow rate of 10 mL water min−1 and 15 g water g−1 BSG. The results revealed that SWH attacked the hemicellulose structure, releasing arabinose (46.54 mg g–1) and xylose (39.90 mg g–1) sugars, and proteins (34.89 mg g–1). The start-up of anaerobic reactors using pretreated BSG (747.71 L CH4 kg−1 TVS) increased the methane yield compared with the reactor without pretreatment (53.21 L CH4 kg−1 TVS). For the process with pretreatment, the generation of electricity (134 kWh t−1 BSG) and heat (604 MJ t−1) are responsible for the mitigation of 43.90 kg CO2 eq t−1 BSG. The adoption of SWH as an eco-friendly pretreatment of biomass for AD could be a technological route to increase methane-rich biogas and bioenergy production, supporting the circular economy transition by reducing the carbon footprint of the beer industry.

Subcritical Water Hydrolysis of Fresh and Waste Cooking Oils to Fatty Acids Followed by Esterification to Fatty Acid Methyl Esters: Detailed Characterization of Feedstocks and Products.

In this present work, the hydrolysis of a sample of rapeseed oil (RSO) and two waste cooking oil (WCO) samples in subcritical water has been carried out in a stirred batch stainless-steel reactor to produce fatty acids. Using RSO as a model triglyceride, the effects of reaction parameters on the yields of fatty acids were investigated to determine the optimum set of hydrolysis conditions to be a temperature of 300 °C, a reaction time of 60 min, and a vegetable oil-water mass ratio of 1:2. The set of optimum conditions was applied to the hydrolysis of the WCOs. Oleic acid was the dominant fatty acid with yields of 74.4 wt % from RSO and 57.5 and 72.4 wt % from the two WCOs, respectively, while palmitic acid was the second most abundant fatty acid with yields of up to 31 wt %. The feedstocks and fatty acid products were characterized by acid-base titration and thermogravimetric analysis (TGA). Thereafter, the hydrolysis products from the optimum conditions were esterified to their fatty acid methyl esters (FAMEs), which were further characterized by gas chromatography-mass spectrometry (GC/MS) and TGA. With RSO at the optimum hydrolysis conditions, acid-base titration gave a fatty acid yield of 97.2 wt %, while TGA gave 86 wt %. Under the same conditions, the yield of FAMEs from GC/MS analysis was 88.6 wt %, while TGA gave a FAMEs' yield of 91 wt %. This study showed that the simple TGA method provided detailed and complete characterization of lipid feedstocks and their conversion products. In addition, subcritical water hydrolysis can be used to valorize WCOs to fatty acids, with little or no extensive feedstock purification, for various applications including biodiesel production.

Simulation and Optimization of Lignocellulosic Biomass Wet- and Dry-Torrefaction Process for Energy, Fuels and Materials Production: A Review

This review deals with the simulation and optimization of the dry- and wet-torrefaction processes of lignocellulosic biomass. The torrefaction pretreatment regards the production of enhanced biofuels and other materials. Dry torrefaction is a mild pyrolytic treatment method under an oxidative or non-oxidative atmosphere and can improve lignocellulosic biomass solid residue heating properties by reducing its oxygen content. Wet torrefaction usually uses pure water in an autoclave and is also known as hydrothermal carbonization, hydrothermal torrefaction, hot water extraction, autohydrolysis, hydrothermolysis, hot compressed water treatment, water hydrolysis, aqueous fractionation, aqueous liquefaction or solvolysis/aquasolv, or pressure cooking. In the case of treatment with acid aquatic solutions, wet torrefaction is called acid-catalyzed wet torrefaction. Wet torrefaction produces fermentable monosaccharides and oligosaccharides as well as solid residue with enhanced higher heating value. The simulation and optimization of dry- and wet-torrefaction processes are usually achieved using kinetic/thermodynamic/thermochemical models, severity factors, response surface methodology models, artificial neural networks, multilayer perceptron neural networks, multivariate adaptive regression splines, mixed integer linear programming, Taguchi experimental design, particle swarm optimization, a model-free isoconversional approach, dynamic simulation modeling, and commercial simulation software. Simulation of the torrefaction process facilitates the optimization of the pretreatment conditions.

Hierarchical Cu2O/NiFeCo layered double hydroxide nanoarrays on copper foam obtained by a self-sacrificial templated route for a highly efficient oxygen evolution reaction

The design of highly active, economical and highly stable electrocatalysts for the oxygen evolution reaction (OER) is very important for realizing sustainable energy conversion. Herein, a Cu2O/NiFeCo layered double hydroxide electrode on a copper foam (CF) with a nanoarray structure (Cu2O/NiFeCo LDH/CF) is fabricated by using Cu(OH)2 on CF (Cu(OH)2/CF) as a self-sacrificial template. The prepared Cu2O/NiFeCo LDH/CF has a unique hierarchical nanostructure, high electrochemical active area and excellent integration of Cu2O and NiFeCo LDH, resulting in low overpotentials of 228 mV and 269 mV for current densities of 10 and 100 mA cm−2 in 1 M KOH, respectively, as well as an ultrasmall Tafel slope of 40 mV dec−1. In highly alkaline 6 M KOH, a overpotential of only 213 mV can deliver a current density of 100 mA cm−2. Moreover, the assembled water hydrolysis device operates stably for 50 h without a significant change in the potential in the strong alkaline solution. This high-efficiency OER performance and long-term stability make Cu2O/NiFeCo LDH/CF promising for practical applications.

Risk Assessment of Subcritical Water Hydrolysis (SWH) System for Sugar Recovery using Failure Modes and Effects Analysis (FMEA) Methods

The subcritical water hydrolysis (SWH) process has proven to be an effective method for sugar recovery from bakery waste. However, the natural principle of the process involving high pressure and temperature has made it a hazardous operation. Hence, failure mode and effect analysis (FMEA) has been applied to identify the potential failure modes in subcritical water hydrolysis (SWH) systems. The Risk Priority Number (RPN) approach was used to rate each potential problem during the SWH process. The reactor unit was found to have the highest potential for failure by RPN value of 800 with the 'failure effect analysis' on the potential reactor cap to explode due to the very high pressure inside the reactor that developed during SWH. The failure consequences may lead to injury or even death. As a result of the FMEA assessment approach and several corrective action plans, the failure risks of SWH can be reduced and managed effectively.

Integrated rice bran processing by supercritical CO2 extraction and subcritical water hydrolysis to obtain oil, fermentable sugars, and platform chemicals

Rice bran is rich in oil and constituted by a lignocellulosic structure, which is a potential raw material for its processing into several products. Therefore, the oil yield and composition of oil obtained from supercritical CO2 extraction were investigated to select a condition for using defatted rice bran for processing by subcritical water hydrolysis. The effects of temperature (230 °C and 260 °C) and solvent-to-feed mass ratio (50 and 100 g water/g defatted rice bran) on fermentable sugar yield (YFS) and hydrolysate composition were evaluated and discussed. Supercritical CO2 extraction at 40 °C and 20 MPa provided an oil yield of 17.19 wt% at 120 min. For defatted rice bran, the highest YFS (6.53 g sugars/100 g defatted rice bran) was obtained at 260 °C and 100 g water/g defatted rice bran.

Improvement of gaseous bioenergy production from spent coffee grounds Co-digestion with pulp wastewater by physical/chemical pretreatments

Two steps of hydrolysis and anaerobic biogas production processes was investigated in this study. In the first step, subcritical water (SBW) hydrolysis and chemical (acid/alkali) pretreatments were carried out to enhance hydrolysis efficiency by obtaining and analyzing the total volatile fatty acids (TVFA), chemical oxygen demand (COD), and total sugar productions from spent coffee grounds (SCG) hydrolysate. The subcritical water (SBW) hydrolysis under the condition of temperature 150 °C for 30 min can greatly improve the organic matter breakdown and reached the COD concentration of 1010 g/L which was 30% higher than the untreated raw SCG. For chemical pretreatments, it was found that the alkaline hydrolysis of SCG resulted in the greatest total sugar concentration of 181 g/L whereas the operation conditions were 2.0 M NaOH at 60 °C for 1 h. The peak of TVFA concentration 3725 mg/L was found at the acid hydrolysis of SCG with 1.0 M H2SO4 acid, 60 °C for 1 h. The optimal biomethane yield of 115 mL/g COD was obtained when 1.0 M H2SO4 acid hydrolysate co-digestion with pulp wastewater which increase methane yield production 8 times of raw pulp wastewater. The pretreatment process was confirmed in this study can significant improve the converting of the biowastes to bioenergy efficiency.

Oxygen-Sensitive Photo- and Radioluminescent Polyurethane Nanoparticles Modified with Octahedral Iodide Tungsten Clusters.

The development of cancer treatment techniques able to cure tumors located deep in the body is an urgent task for scientists and physicians. One of the most promising methods is X-ray-induced photodynamic therapy (X-PDT), since X-rays have unlimited penetration through tissues. In this work, octahedral iodide tungsten clusters, combining the properties of a scintillator and photosensitizer, are considered as a key component of nanosized polyurethane (pU) particles in the production of materials promising for X-PDT. Cluster-containing pU nanoparticles obtained here demonstrate bright photo- and X-ray-induced emission in both solid and water dispersion, great efficiency in the generation of singlet oxygen, and high sensitivity regarding photoluminescence intensity in relation to oxygen concentration. Additionally, incorporation of the cluster complex into the pU matrix greatly increases its stability against hydrolysis in water and under X-rays.

Potential of subcritical water hydrolyzed soybean husk as an alternative biosorbent to uptake basic Red 9 dye from aqueous solutions

Bioethanol produced from lignocellulosic sources still faces problems related to the feasibility of this technological route. Within the biorefinery concept and clean technology, subcritical water hydrolysis (SWH) is efficient for dissociating lignocellulosic biomass. The solid co-products can be used for other applications to become SWH a more feasible process. The potential use of subcritical water hydrolyzed soybean husks (SWHSH) as a biosorbent to remove basic Red 9 dye (BR9) from aqueous solutions was evaluated in this study. SWHSH was efficient in the uptake of BR9, mainly at a pH of 8.0. The Langmuir model satisfied the biosorption equilibrium profile with a biosorption capacity of 56.8 mg g−1. The thermodynamic parameters indicate that the biosorption is spontaneous, with the ΔG0 ranging from − 22.08 to − 24.88 kJ mol1, with an endothermic nature (ΔH0 = 5.59 kJ mol−1). The biosorption equilibrium was in 60 min for all the initial concentrations studied. The Linear Driving Force (LDF) model fitted the data well, furnishing diffusivity values from 1.41 to 2.00 × 10−8 cm2 s−1. Desorption was also possible under acid conditions, and SWHSH could be effectively used 3 times. Last, the fixed-bed biosorption showed that the SWHSH could remove the BR 9 dye up to 180 min without regeneration, presenting a biosorption capacity of 46.1 mg g1 for 900 mL of treated effluent with an initial concentration of 200 mg L1. The characterization and biosorption results indicate that the BR9 tends to be adsorbed by physical forces, possibly by hydrogen bonds, electrostatic interaction, ππ interaction, and cation-π interaction. Overall, the SWHSH demonstrated potential application as a biosorbent for the removal of BR9.

Direct Observation of Adhesion and Mechanical Behavior of a Single Poly(lactic-co-glycolic acid) (PLGA) Fiber Using an In Situ Technique for Tissue Engineering.

Nanometer- and submicrometer-sized fiber have been used as scaffolds for tissue engineering, because of their fundamental load-bearing properties in synergy with mechano-transduction. This study investigates a single biodegradable poly(lactic-co-glycolic acid) (PLGA) fiber's load-displacement behavior utilizing the nanoindentation technique coupled with a high-resolution in situ imaging system. It is demonstrated that a maximum force of ∼3 μN in the radial direction and displacement of at least 150% of fiber diameter should be applied to acquire the fiber's macroscopic mechanical properties for tissue engineering. The adhesion behavior of a single fiber is captured using a high-resolution camera. The digital image correlation (DIC) technique is adopted to quantify the adhesion force (∼25 μN) between the fiber and the tip. Adhesion force has also been quantified for the fiber after immersing in phosphate-buffered saline (PBS) to mimic the bioenvironment. A 4-fold increase in adhesion force after PBS treatment was observed due to water penetration and hydrolysis on the fiber's surface. A high similarity between mechanical properties of a single fiber and native tissues (elastic modulus of 10-25 kPa) and superior adhesion force (25-107.25 μN) was observed, which is excellent for promoting cell-matrix communication. Overall, this study examines the mechanics of a single fiber using innovative indentation and imaging processing techniques, disclosing its profound and striking roles in tissue engineering.

Interactive Performance of Wheat Nitrogen Fertilization and Inoculation with Growth-Promoting Bacteria

The exploitation of plant growth-promoting rhizobacteria (PGPR) emerges as an important strategy for fixing atmospheric nitrogen (N) and making it available to plants. Correspondingly, the purpose of this study was to evaluate the inoculation with Azospirillum brasilense via foliar with distinct N doses (40, 20, and 0 kg/ha) for different wheat cultivars (Sossego, Toruk, and Quartzo). The experiment was conducted during the 2020 harvest at the State University of Rio Grande do Sul, Cachoeira do Sul, Brazil. A completely randomized design (CRD) in a 3x6 factorial scheme with four replications was applied. Yield components and grain yield were established. Furthermore, the physicochemical characterization of wheat siliqua biomass was executed based on subcritical water hydrolysis (SWH). Gluten and mass analysis was established. Appropriately, the grain yield was up to 3197.05 kg/ ha for the Sossego cultivar with the N dose of 40 kg/ ha. Up to 0.84 g reducing sugars/ 100 g wheat siliqua was obtained based on the SWH. Finally, this study promoted N management as a key factor in increasing grain yield. This scenario reports the importance of the association of PGPRs as a fundamental promoter of N for plants to express their maximum potential.

MOF-Like 3D Graphene-Based Catalytic Membrane Fabricated by One-Step Laser Scribing for Robust Water Purification and Green Energy Production

HighlightsA novel multifunctional three-dimensional graphene-metal frame film for the combination of water purification and hydrolysis hydrogen production, which has excellent purification efficiency and extremely low energy consumption. A “green” one-step laser scribing technology without any organic solvent in the whole preparation process. Metal nanoparticles as the active site can be loaded in a graphene film and wrapped by graphene, preventing undesirable aggregation and increasing catalytic active sites.

Water Induced Structural Transformations in Flexible Two-Dimensional Layered Conductive Metal–Organic Frameworks

The flexible and ever-changing layered structure of electrically conductive 2D metal–organic frameworks (MOFs) poses a formidable challenge for establishing any structure–application relationships. Here, we employ a combined quantum mechanics and classical molecular dynamics (MD) approach allowing large-scale/long-time simulations of the dynamics of both dry and hydrated systems to investigate the intrinsic flexibility and dynamical motions of layered 2D MOFs and its effect on their physical and chemical properties. The Co3(HHTP)2 and Cu3(HHTP)2 [HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene] MOFs as two representatives of the layered family of MOFs are studied in great details with a focus on their experimentally observed differential framework stabilities in aqueous solutions. Our MD simulations reproduce structural properties of both MOFs as well as a higher tendency of the Co3(HHTP)2 MOF towards water attack and hydrolysis than its Cu3(HHTP)2 counterpart, in agreement with available experimental reports. The results show the presence of two distinctive metastable metal centers with (pseudo)planar vs (pseudo)tetrahedral configurations where the latter are more positively charged than the former and hence more susceptible to water nucleophilic attacks. The accurate ωB97M-v quantum-mechanical calculations show the higher tendency of the open Co2+ sites for coordination to water molecules than the open Cu2+ sites. Our multifaceted strategy paves the way towards simulation of realistic MOF-based materials and their interface with confined water molecules which is especially relevant to designing more robust water stable materials with desired properties and applications.

Bioactive peptides-derived from marine by-products: development, health benefits and potential application in biomedicine

Increased fisheries products have raised by-products that are discarded due to low economic value. In addition, marine by-products are still rich in protein and nutritional value that have biological activities and give benefits to human health. Meanwhile, there is raised pressure for sustainability practices in marine industries to reduce waste and minimize the detrimental effect on the environment. Thus, valorization by-products through bioactive peptide mining are crucial. This review focus on various ways to obtain bioactive peptides from marine by-products through protein hydrolysis, for instance chemical hydrolysis (acid and based), biochemical hydrolysis (autolysis and enzymatic hydrolysis), microbial fermentation, and subcritical water hydrolysis. Nevertheless, these processes have benefits and drawbacks which need to be considered. This review also addresses various biological activities that are favorable in pharmaceutical industries, including antioxidant, antihypertensive, anticancer, anti-obesity, and other beneficial bioactivities. In addition, some potential marine resources of Indonesia for the marine biopeptide from their by-product or undesired marine commodities would be addressed as well.

Controlling Reaction Routes in Noble‐Metal‐Catalyzed Conversion of Aryl Ethers

AbstractHydrogenolysis and hydrolysis of aryl ethers in the liquid phase are important reactions for accessing functionalized cyclic compounds from renewable feedstocks. On supported noble metals, hydrogenolysis is initiated by a hydrogen addition to the aromatic ring followed by C−O bond cleavage. In water, hydrolysis and hydrogenolysis proceed by partial hydrogenation of the aromatic ring prior to water or hydrogen insertion. The mechanisms are common for the studied metals, but the selectivity to hydrogenolysis increases in the order Pd<Rh<Ir<Ru≈Pt in decalin and water; the inverse was observed for the selectivity to hydrolysis in water. Hydrogenolysis selectivity correlates with the Gibbs free energy of hydrogen adsorption. Hydrogenolysis has the highest standard free energy of activation and a weak dependence on H2 pressure, thus, the selectivity to hydrogenolysis is maximized by increasing temperature and decreasing H2 pressure. Selectivity to C−O bond cleavage reaches >95 % in water and alkaline conditions.

Controlling Reaction Routes in Noble-Metal-Catalyzed Conversion of Aryl Ethers.

Hydrogenolysis and hydrolysis of aryl ethers in the liquid phase are important reactions for accessing functionalized cyclic compounds from renewable feedstocks. On supported noble metals, hydrogenolysis is initiated by a hydrogen addition to the aromatic ring followed by C−O bond cleavage. In water, hydrolysis and hydrogenolysis proceed by partial hydrogenation of the aromatic ring prior to water or hydrogen insertion. The mechanisms are common for the studied metals, but the selectivity to hydrogenolysis increases in the order Pd<Rh<Ir<Ru≈Pt in decalin and water; the inverse was observed for the selectivity to hydrolysis in water. Hydrogenolysis selectivity correlates with the Gibbs free energy of hydrogen adsorption. Hydrogenolysis has the highest standard free energy of activation and a weak dependence on H2 pressure, thus, the selectivity to hydrogenolysis is maximized by increasing temperature and decreasing H2 pressure. Selectivity to C−O bond cleavage reaches >95 % in water and alkaline conditions.