Catalytic torrefaction effect on waste wood boards for sustainable biochar production and environmental remediation.

Wood boards used in construction are generally treated with toxic chemicals, making them unsuitable for further use and causing environmental pollution. This study evaluates the possibility of using catalytic torrefaction as a pretreatment to improve wood pyrolysis and combustion for greener biochar production. Waste beech boards were impregnated with different K2CO3 solutions (0-0.012 M), then torrefied between 5 and 60 min at 275 °C. The ICP-AES showed that the board's surface held more potassium than the core. Torrefaction coupled with potassium decreased the C-O and -OH stretches. Thermogravimetric analysis of torrefied wood showed that the board's internal heating degraded the core more than the surface. The exothermic reactions made potassium's catalytic action more efficient in the core. Interactions between the potassium content and torrefaction duration decreased the pyrolysis' maximum devolatilization temperature. During combustion, potassium decreased the ignition temperature by up to 9% and 3% at the surface and core, respectively, while the torrefaction increased it. The catalytic torrefaction significantly decreased the devolatilization peak during combustion, thus making the wood's combustion similar to that of coal, having only the char oxidation step. These findings highlight the advantages and challenges of waste wood's catalytic-torrefaction for biochar production to reduce environmental pollution.

A review of biowaste remediation and valorization for environmental sustainability: Artificial intelligence approach.

Biowaste remediation and valorization for environmental sustainability focuses on prevention rather than cleanup of waste generation by applying the fundamental recovery concept through biowaste-to-bioenergy conversion systems - an appropriate approach in a circular bioeconomy. Biomass waste (biowaste) is discarded organic materials made of biomass (e.g., agriculture waste and algal residue). Biowaste is widely studied as one of the potential feedstocks in the biowaste valorization process due to its being abundantly available. In terms of practical implementations, feedstock variability from biowaste, conversion costs and supply chain stability prevent the widespread usage of bioenergy products. Biowaste remediation and valorization have used artificial intelligence (AI), a newly developed idea, to overcome these difficulties. This report analyzed 118 works that applied various AI algorithms to biowaste remediation and valorization-related research published between 2007 and 2022. Four common AI types are utilized in biowaste remediation and valorization: neural networks, Bayesian networks, decision tree, and multivariate regression. The neural network is the most frequent AI for prediction models, the Bayesian network is utilized for probabilistic graphical models, and the decision tree is trusted for providing tools to assist decision-making. Meanwhile, multivariate regression is employed to identify the relationship between experimental variables. AI is a remarkably effective tool in predicting data, which is reportedly better than the conventional approach owing to its characteristics of time-saving and high accuracy. The challenge and future work in biowaste remediation and valorization are briefly discussed to maximize the model's performance.

Highly Branched Tannin-Tris(2-aminoethyl)amine-Urea Wood Adhesives.

Condensed tannin copolymerized with hyperbranched tris(2-aminoethyl)amine-urea formed by amine-amido deamination yields a particleboard thermosetting adhesive without any aldehydes satisfying the requirements of relevant standards for the particleboard internal bond strength. The tannin-triamine-urea cures well at 180 °C, a relatively low temperature for today's particleboard hot pressing. As aldehydes were not used, the formaldehyde emission was found to be zero, not even in traces due to the heating of wood. The effect is ascribed to the presence of many reactive sites, such as amide, amino, and phenolic groups belonging to the three reagents used. The tannin appears to function as an additional cross-linking agent, almost a nucleating agent, for the triamine-urea hyperbranched oligomers. Chemical analysis by MALDI ToF and 13C NMR has shown that the predominant cross-linking reaction is that of the substitution of the tannin phenolic hydroxyls by the amino groups of the triamine. The reaction of tannin with the still-free amide groups of urea is rather rare, but it may occur with the rarer tannin flavonoid units in which the heterocyclic ring is opened. Due to the temperature gradient between the surfaces and the board core in the particleboard during hot pressing, the type and the relative balance of covalent and ionic bonds in the resin structure may differ in the surfaces and the board core.

Furanic Polymerization Causes the Change, Conservation and Recovery of Thermally-Treated Wood Hydrophobicity before and after Moist Conditions Exposure.

The Whilhelmy method of contact angle, wood thermal properties (TG/DTG), infrared spectroscopy, etc. was used to define the hydrophobicity of heat-treated beech and fir wood at increasing temperatures between 120 °C and 300 °C. By exposure to wet conditions during 1 week, the hydrophobic character obtained by the heat treatment remains constant heat-treated. Heat induced wood hydrophobation, was shown by CP MAS 13C NMR and MALDI ToF mass spectrometry to be mainly caused by furanic moieties produced from heat-induced hemicelluloses degradation. This is caused by the acid environment generated by the hydrolysis of the hemicelluloses acetyl groups. Furfural polymerizes to linear and branched oligomers and finally to water repellent, insoluble furanic resins. The water repellent, black colored, cross-linked polymerized furanic network is present throughout the heat-treated wood. Wood darkening as well as its water repellency due to increasing proportions of black colored furanic resins increase as a function of the increase with treating temperature, becoming particularly evident in the 200 to 300 °C treating temperature range.

Pyrolysis kinetics of potassium-impregnated rubberwood analyzed by evolutionary computation.

To explore the catalytic effect of potassium on pyrolysis characteristics of biomass, the rubberwood is pyrolyzed by a thermogravimetric analyzer. The samples are impregnated by three concentrations of potassium carbonate (0.004 M, 0.008 M, and 0.012 M). The pyrolysis kinetics is analyzed by an independent parallel reaction (IPR) model to describe the catalytic effect on the four-pseudo components model in the rubberwood. The particle swarm optimization (PSO) is adopted to optimize the fit quality between the established kinetic models and experimental data. It is found that the pyrolysis of rubberwood impregnated with 0.012 M concentration of K2CO3 can reduce the activation energy of cellulose from 223.86 to 204.14 kJ mol-1, whereas there is no obvious effect on the activation energies of hemicelluloses and lignin. The starting temperature and ending temperature of cellulose thermodegradation also move toward lower temperatures, indicating that the addition of potassium enhances the degradation of cellulose.

Evaluation of thermally modified Grevillea robusta heartwood as an alternative to shortage of wood resource in Kenya: Characterisation of physicochemical properties and improvement of bio-resistance.

Heat treatment of Grevillea robusta, a tropical wood species of low natural durability, was carried-out under inert conditions to improve its decay resistance. Resistance of heat treated samples was evaluated by malt agar block tests after three months of exposure to several wood rotting fungi. Also resistance of heat treated wood against termites was tested in the laboratory and in the field. Results showed that durability against fungi and termites was greatly improved after treatment. There was a good correlation between decay resistance and mass loss due to thermal treatment. Microscopic, FTIR and (13)C MAS NMR analysis were performed to characterize wood chemical and anatomical modifications that occur after treatment to understand the reasons of the durability improvement.