Wood Waste Research Articles

Aromatic rich biofuel production via catalytic co‐pyrolysis of paulownia wood and polypropylene waste

AbstractThermo‐catalytic co‐pyrolysis of paulownia wood and polypropylene mixture were carried out in a fixed bed horizontal reactor system. The biochar obtained from pyrolysis of paulownia wood was activated by steam at 700°C. Activated biochar supported magnesium oxide, nickel oxide and cobalt oxide catalysts were prepared by incipient miosture impregnation and were used to upgrade the bio‐oil. Catalytic pyrolysis reduced the amount of bio‐oil compared with non‐catalytic pyrolysis (59.5% of bio‐oil). The results indicate that the production of aromatic compounds increased from 40.35% to 65.93, 62.12 and 61.56% using Ni, Co and Mg catalysts, respectively. For all three catalysts, the production of furan compounds decreased. It was found that bio‐char based catalysts are suitable for use in the co‐pyrolysis process to improvement the biofuel production.

Encouraging Invasive Acacia Control Strategies by Repurposing Their Wood Biomass Waste for Pulp and Paper Production

Concerns on the expanding infestation of several Acacia species in the southern Mediterranean European countries have triggered an ever-growing requirement for costly targeted control actions. Valorizing biomass waste produced could help promote and better finance these actions. For that purpose, wood wastes from invasive control actions were tested regarding their pulp and paper potential, aiming to entice cellulose industries to partake in future conservation actions. Wood waste from the five most pervasive Acacia species was studied (Acacia dealbata Link, Acacia longifolia Willd, Acacia mearnsii De Wild, Acacia melanoxylon R.Br, and Acacia saligna Labill) regarding physical and chemical characteristics, and a central composite design was used to optimize alkali charge and reaction temperature on pulping yield and delignification. Bleached kraft pulps were produced with each species’ optimized conditions and for an equitable mixture of all species. Optimized pulp yields (52.6%–53.5%) and pulp polymerization degree (2867–3690) of Acacia species were higher than those of Eucalyptus globulus Labill (used as reference). Optimized bleached pulps were refined and fiber, pulp, and handsheet properties determined. Acacia dealbata and A. longifolia presented high specific wood consumption and lower handsheet strength properties, pointing to overall lower pulping potential, while A. melanoxylon and A. mearnsii characteristics were equal to or higher than those of E. globulus. A. saligna pulp and handsheet characteristics appear more suited for tissue paper. The Acacia mixture achieved acceptable characteristics, enabling the indiscriminate use of Acacia wood regardless of the species. As a shortcoming, the Acacia pulps showed the worst optical characteristics, with brightness dropping substantially with beating (64%–76%) when compared to E. globulus (81%).

Preparation and performance research of ecological concrete using waste wood

To mitigate environmental damage from mineral aggregate extraction, bio-based materials have garnered research interest as potential replacements for natural mineral aggregates. This work utilized waste wood as filler to prepare lightweight foam concrete with thermal insulation, low-temperature and corrosion resistance properties. The feasibility of using wood aggregate-based foam concrete (WFC) was explored in terms of dry density, softening coefficient, compressive strength, thermal conductivity, chloride ion permeability, freezing resistance, and sulfate attack resistance. Results showed that simultaneous addition of waste wood aggregate (WA) and foam effectively reduced WFC bulk weight and thermal conductivity while enhancing water resistance. However, the porous morphology of WA and foam caused the reduction of mechanical properties. In terms of durability, the addition of WA can increase the energy absorption capacity when WFC is subjected to expansion stress, reduce the damage to the structure, and have an inhibiting effect on the cracking of WFC caused by sulfate attack and freeze-thaw cycles. Nevertheless, WA's high water absorption loosened the matrix in WFC's interfacial transition zone (ITZ), increasing harmful pores and negatively affecting durability. In addition, in order to predict the mechanical properties of WFC and the resistance to sulfate attack, this study established a function model for the relationship between the compressive strength (Maintenance specimens of the same age and Specimen of sulfate attack) and the WA dosage. In conclusion, The use of waste wood for the preparation of WFC is more advantageous and sustainable than conventional foam concrete for the insulation of precast walls and coastal structures.

Integrated biorefinery approach for utilization of wood waste into levulinic acid and 2-Phenylethanol production under mild treatment conditions

In a bid to explore the on-site biorefinery approach for conversion of forestry residues, lignocellulosic biomass into value-added products was studied. The bark white pine wood was subjected to the microwave technique of fast and slow hydrolysis under varying acid and biomass concentrations to produce levulinic acid (LA). The HCl (2% v/v) and plant biomass (1% w/v) were identified as the optimum conditions for fast wood hydrolysis (270 ºC for 12 sec), which led to maximum LA yield of 446.68 g/kgPB. The proposed sustainable approach is mild, quick, and utilized a very low concentration of the HCl for the production of LA. The hydrolysate was used as a medium for Kluyveromyces marxianus growth to produce 2-phenylethanol (2-PE). K. marxianus used 74–95% of furfural from hydrolysate as a co-substrate to grow. The proposed model of the integrated biorefinery is an affordable on-site approach of using forest waste into localized solutions to produce LA and 2-PE.

Syngas composition analysis for waste to methanol production: Techno-economic assessment using machine learning and Aspen plus

The yield of methanol is heavily influenced by the composition of the syngas which varies from waste type and gasification conditions. This study uniquely explores machine learning (ML) and artificial neural network (ANN) algorithms with shapley additive values (SHAP) analysis to predict syngas compositions and interpret the complexities of waste gasification. Aspen Plus is then utilized to investigate the impact of syngas compositions on the economics of methanol production. Among the different ML models, gradient boosting regression achieved remarkable accuracy in predicting carbon monoxide and carbon dioxide, while ANN excelled in predicting nitrogen and hydrogen based on the coefficient of determination (>0.95). The feature importance analysis demonstrated the gasification agent type as the most important feature. Steam gasification of waste sawdust, straw, and wood chips showed the highest methanol yield. Economic analysis indicated the lowest levelized cost of methanol (LCMeOH) to be 1195.79 USD/MT which further decreased to 933.97 USD/MT upon hydrogen addition. Uncertainty analysis using Monte Carlo method showed the possible minimum LCMeOH to be 254.05 USD/MT. This study provides a comprehensive picture of the economic viability of waste-to-methanol production and provides an important reference for stakeholders on a global scale to quickly assess the feasibility of waste-to-energy projects.

Effect of crystalline admixture on shrinkage and alkali-silica reaction of biochar-cementitious composites

This study investigated effects of crystalline admixture (CA) on shrinkage and alkali-silica reaction behaviours of cementitious composites. Addition of 1-1.5 wt% superabsorbent polymer (SAP) completely mitigated autogenous shrinkage while slightly increasing the 120-day total shrinkage of the SP-cement composite by 5.7%, resulting in the highest apparent porosity. 1-1.5 wt% CA addition did not affect the autogenous shrinkage while slightly reducing the 120-day total shrinkage by 10.1%. The combination of CA and waste wood biochar (WWB) reduced autogenous shrinkage by 24.23% and 120-day total shrinkage by 23.6%, resulting in the lowest apparent porosity. The formation of hydration products in the WWB pores and on WWB surface densified the cementitious matrix, leading to a reduction in water evaporation. Furthermore, for specimens exposed to 1M NaOH solution at 80 °C, CA addition significantly reduced the 120-day expansion by 50.6%, while the combination of CA and WWB addition reduced the 120-day expansion by 42.9%.

Experimental study on the preparation of wood aggregate recycled concrete using waste wood and recycled fine aggregate from construction and demolition wastes

As a renewable resource, wood has the advantages of a high strength-weight ratio, high yield and excellent thermal insulation. Meanwhile, the resource utilization of large quantities of waste wood, waste furniture and mixed wood generated by the demolition of old houses and the removal of building formwork are basically in a blank state. Therefore, in this study, construction solid waste—waste wood and recycled fine aggregate were used as coarse and fine aggregates to replace natural sand and gravel, respectively, and synergized with three cementitious materials (sulfoaluminate cement, portland cement and geopolymer cement) to prepare wood aggregate recycled concrete (WARC). Focus on the evolution law of basic property, thermal insulation property, mechanical property, shrinkage property, environmental and economic benefits of WARC. The results showed that the mechanical and shrinkage properties of WARC were deteriorated by using WA and recycled fine aggregate (RFA) instead of natural aggregates. The dry density of WARC was as low as 1770 kg/m3. The 28 d maximum compressive and flexural strength were 34.8 and 5.69 MPa, which were better than traditional C30 concrete. Compared with conventional concrete, WARC has excellent thermal insulation properties. The thermal conductivity was reduced by up to 81.9 % compared to traditional concrete, which would make WARC very promising for non-structural components (green insulated wall materials and precast wall panels, etc.). By calculating CO2 emissions and compressive strength-cost efficiency values, it was found that the WARC prepared with geopolymer cement could reduce CO2 emissions by 31.3 % while possessing good mechanical properties and economic benefits, making it the optimal cement-based material for preparing WARC.

Use of scrap particleboard to produce recycled particleboard

Recycling is presently the most environmentally friendly approach that deals with wood waste. Each year a huge amount of particleboard completes its service life and needs to be disposed of or recycled. Scrap particleboard has the potential to be reused as raw material for particleboard production. A crucial step for producing particleboards using scrap particleboards is to break down urea-formaldehyde (UF) resins in the scrap particleboards to obtain separated particles. In this study, liquid hot water (LHW) pretreatment was employed to decompose the UF resins to detach and recover wood particles from the scrap particleboards. The recovered wood particles and fresh industrial wood particles in different proportions were used as the raw material for the particleboard. The physical and mechanical properties of the recycled particleboards were evaluated. The modulus of rupture (MOR), modulus of elasticity (MOE), and internal bond (IB) of the recycled particleboards were lower than those of the particleboards made with fresh wood particles. However, the 2 h thickness swelling (TS) of the recycled particleboards was better than that of the fresh particleboards, indicating that the recycled particleboards were more dimensionally stable. The mechanical properties of the particleboards containing up to 40% recycled wood particles met the minimum Chinese National Standard requirements for general-purpose particleboards. Conclusively, scrap wood particleboards could be utilized as raw material in particleboard production.

From wood waste to recyclable plastic

From wood waste to recyclable plastic

Mechanical and acoustic performance of mortar with partial replacement by biochar from civil construction wood waste at advanced ages

Civil construction generates large amounts of solid waste, most of which are non-toxic, but extremely voluminous, resulting in a contemporary sanitary health problem. Furthermore, cement fabrication, a widely used binding material, is responsible for the emission of 8% of the world’s CO2 into the atmosphere, making it an industry with a great environmental impact. The consumption figures of cement show an significant increasing over the years. Therefore, much research has focused on the search for energy efficiency in the production processes of cement and materials with potential use as additions, allowing the reduction of clinker consumption, the main component of the cement. In this sense, this research made use of wood waste from civil construction, and through the pyrolysis process, partially replaced cement with biochar at high levels compared to existing research, seeking to find an efficient replacement limit and analyzing its sound absorption and mechanical properties at advanced ages. Mortars were produced with levels of 5%, 10%, and 15% (m/m), replacing cement with biochar. The results demonstrated better mechanical performance at advanced ages, up to 30% for compression and 15% for tensile strength with 10% biochar, and lower water absorption by capillarity. Its acoustic performance showed that the samples with biochar did not exhibit properties of a sound-absorbing material.

Early detection of deep-seated smouldering fires in wood waste storage using ERT

Incidents of waste and biofuel fires are common at all stages of the waste recycling chain and have grave implications for business, employees, firefighters, society, and environment. An early detection of waste and biofuel fires in the smouldering stage could save precious lives, resources, and our environment. Existing fire detection methodologies e.g. handheld temperature sensors, IR cameras, gas sensors, and video and satellite-based monitoring techniques have inherent limitations to efficiently detect smouldering fires. An attempt was made to explore the potential of electrical resistivity tomography (ERT) as an alternate tool to address the problem. In the experiments an externally powered resistive wire was employed to initiate the smouldering fire inside the test material (wood pellets, wood shavings, wood fines). Time series of ERT that followed the initiation and development of smouldering were recorded using an automated monitoring instrument setup. The actual geometry of the experimental sample container and electrode setup was integrated in the 3D finite element method (FEM) model grid to perform inverse numerical modelling (inversion) and to develop resistivity tomographic images. The study shows a sharp increase in ratio of resistivity (R/Ro ≥ 50 %) in the test material in the region of smouldering hotspot and demonstrates the potential use of ERT technique for the detection of smouldering hotspots in silos and pile storage of organic material such as wood-based fuels, wood waste, coal, municipal solid waste (MSW), recyclables etc. More research is however required for enabling the use of this technique at the practical scale for different storage conditions.

Early life ambient air pollution, household fuel use, and under-5 mortality in Ghana

IntroductionEnvironmental exposures, such as ambient air pollution and household fuel use affect health and under-5 mortality (U5M) but there is a paucity of data in the Global South. This study examined early-life exposure to ambient particulate matter with a diameter of 2.5 µm or less (PM2.5), alongside household characteristics (including self-reported household fuel use), and their relationship with U5M in the Navrongo Health and Demographic Surveillance Site (HDSS) in northern Ghana. MethodsWe employed Satellite-based spatiotemporal models to estimate the annual average PM2.5 concentrations with the Navrongo HDSS area (1998 to 2016). Early-life exposure levels were determined by pollution estimates at birth year. Socio-demographic and household data, including cooking fuel, were gathered during routine surveillance. Cox proportional hazards models were applied to assess the link between early-life PM2.5 exposure and U5M, accounting for child, maternal, and household factors. FindingsWe retrospectively studied 48,352 children born between 2007 and 2017, with 1872 recorded deaths, primarily due to malaria, sepsis, and acute respiratory infection. Mean early-life PM2.5 was 39.3 µg/m3, and no significant association with U5M was observed. However, Children from households using “unclean” cooking fuels (wood, charcoal, dung, and agricultural waste) faced a 73 % higher risk of death compared to those using clean fuels (adjusted HR = 1.73; 95 % CI: 1.29, 2.33). Being born female or to mothers aged 20–34 years were linked to increased survival probabilities. InterpretationThe use of “unclean” cooking fuel in the Navrongo HDSS was associated with under-5 mortality, highlighting the need to improve indoor air quality by introducing cleaner fuels.

Waste Prediction Approach Using Hybrid Long Short-Term Memory with Support Vector Machine

As climate change increases the risk of extreme rainfall events, concerns over flood management have also increased. To recover quickly from flood damage and prevent further consequential damage, flood waste prediction is of utmost importance. Therefore, developing a rapid and accurate prediction of flood waste generation is important in order to reduce disaster. Several approaches of flood waste classification have been proposed by various researchers, however only a few focus on prediction of flood waste. In this study, a Long Short-Term Memory (LSTM) and Support Vector Machine (SVM) approach is adapted to address these challenges. Two different raw datasets were obtained from the “Advancing Sustainable Materials Management: Facts and Figures 2015” source. The datasets were for 9 years (1960, 1970, 1980, 1990, 2000, 2005, 2010, 2014, 2015), and are labelled as the materials generated in the Municipal Waste Stream from 1960 to 2015 and the materials Recycled and Composted in Municipal Solid Waste from 1960 to 2015. The waste types were grouped as paper and paperboard (PP), glass (GI), metals (Mt), plastics (PI), rubber and leather (RL), textiles (Tt), wood (Wd), food (Fd), yard trimmings (YT) and miscellaneous inorganic wastes (IW).

Hydrothermal conversion of mango wood wastes and sugarcane bagasse for biofuel production

Hydrothermal conversion of mango wood wastes and sugarcane bagasse for biofuel production

Pit-lake remediation by chemically activated Chlorocardium rodiei: Simultaneous metal ion removal from acidic waters

The current study investigates the valorization of waste wood from a tropical hardwood found in Guyana (Greenheart – Chlorocardium rodiei) to high surface area activated carbons (AC). We subsequently deployed these adsorbents to sequester Mn 2+, Fe3+, and Al3+ from the acidic waters of a recreational bauxite pit-lake. We studied the impact of activation parameters such as temperature, impregnation ratio and acid concentration on the texture and surface chemistry of ACs and demonstrate that optimized low pH at point-of-zero charge (pHpzc) ACs are efficient adsorbents for the target ions. A mesoporous AC with specific surface area of 2208 m2/g, 11 % surface oxygen and pHpzc of 1.98 was produced under optimized conditions. ACs removed 93–100 % of target ions from pit-lake waters at a native pH of 3.1. Al3+ exerted an antagonistic effect on Mn2+ adsorption in synthetic binary ion systems reducing adsorption by as much as 56 %. The Sips Model fitted the adsorption data best predicting maximum adsorption capacities for Mn2+, Fe3+ and Al3+ of 17.8 mg/g, 23.7 mg/g, and 6.12 mg/g for these low pHpzc optimized materials. These materials show great promise in removing heavy metals from acidic waters.

Effect of Reinforcement Ratio and Particle Size on the Physical and Mechanical Performance of Epoxy Matrix Panels and Waste Wood from Iroko Chlorophora excelsa from Cameroon

The use of local materials developed from natural reinforcements remains a major challenge for many researchers in the development of the industry and the fight against pollution. The wood industry generates large quantities of environmental waste, including Iroko wood. To give Iroko a second life, this study uses Iroko sawdust waste to make an epoxy matrix composite material. The composite was produced using a cold pressing technique based on moving the top and bottom plates to a thickness of 10 mm. On this basis, three particle sizes [t < 0.35[, [0.35–0.63[, and [0.63–1[ were used, as well as three reinforcement (R)/matrix (M) percentages of 50R/50M, 60R/40M, and 70R/30M, where R is the reinforcement percentage and M is the matrix percentage. The physical tests, apparent and real density, porosity, moisture content, water absorption rate, absorption and desorption kinetics, diffusion theory, and activation energy were determined by the gravimetric method. A three-point bending test was carried out in accordance with the ASTM D790 for mechanical tests. The results show that the addition of Iroko particles lightens the material by reducing its density. The hydrophilic nature of Iroko particles increases the absorption rate and porosity, with good diffusion capacity as the particle size and percentage increase. The material produced can be light and porous, with possible applications in thermal insulation. In terms of kinetics, Verma et al.’s model best correlates the experimental desorption points for the 3 isotherms, while Page’s model best correlates the water absorption points. The mechanical results show that Young’s modulus and stress at break decrease with an increase in the reinforcement percentage and particle size. The mechanical results can be used to define the material’s applications in construction and furniture. In accordance with the EN312 standard, the composites produced can be classified as type 2 lightweight materials, suitable for use in dry and damp areas.

Development and Characterization of a Micro-Concrete Based on Wood Waste from Sawmills

Development and Characterization of a Micro-Concrete Based on Wood Waste from Sawmills

Pyrolysis of Specific Non-Recyclable Waste Materials: Energy Recovery and Detailed Product Characteristics.

This study explores the pyrolysis process applied to various non-utilized waste materials, specifically focusing on separated plastics from municipal waste, wood waste (including pallets and window frames), paper rejects, and automotive carpets. Different combinations of these waste materials were subjected to pyrolysis, a process involving high-temperature treatment (600 °C) in a nitrogen atmosphere. The resulting products, including biochar, gas, and liquid fractions, as well as the residual waste materials, underwent comprehensive analysis. The evaluation of pyrolysis products emphasizes their quality, energy content, and potential applications. Notably, the pyrolysis gas derived from the combination of separated municipal plastics and waste wood exhibited the highest calorific value at 49.45 MJ/m3. Additionally, Mixture 2, consisting of plastic and wood waste, demonstrated the highest calorific value for the pyrolysis condensate, reaching 30.62 MJ/kg. Moreover, Mixture 3, benefiting from biochar utilization as a sorbent, displayed the highest iodine value at 90.01 mg/g.

Waste para-rubber wood ash and iron scrap for the sustainable preparation of magnetic Fenton catalyst for efficient degradation of tetracycline

This study introduces a sustainable method of synthesizing a magnetic Fenton catalyst. The use of readily available iron scrap waste and para-rubber wood ash from heating and power plants is innovative and cost-effective. The catalyst is obtained from the precursor materials by pyrolysis. The physicochemical properties of the catalyst were characterized to investigate the effects of different iron-to-ash ratios and pyrolysis temperatures. The Fenton process was investigated through the degradation of tetracycline (TC). A catalyst produced with an iron–ash ratio of 1:2 exhibited exceptional performances with a TC removal rate of up to 90 % within 15 min under optimized conditions. The Fenton catalyst also possessed desirable magnetic properties, enabling easy separation. The stable catalyst could be regenerated and was successfully recycled four times while retaining its efficiency. This research not only addresses environmental concerns but also highlights the potential value of two waste materials in the synthesis of advanced Fenton-like catalysts.

Visible Light-Induced Photocatalytic Degradation of Methylene Blue Using Copper-Doped Carbon Dots One-Step Derived from CCA-Wood

Developing novel eco-friendly broad-spectrum visible light photocatalysts for dye removal is one of the urgent problems for water treatment. Here, copper-doped carbon dots (CDs) were reported to be directly fabricated from chromated copper arsenate (CCA) wood waste for the photocatalytic degradation of the methylene blue dye. The properties of the resulting CDs were thoroughly characterized and analyzed, preceding an investigation into the adsorption kinetics of dye degradation. The kinetic study showed that reactant concentration was the rate-limiting factor. The obtained CDs showed a 151 mg/g photocatalytic degradation capacity. Comparing pure CDs to CDs/TiO2 composites, the former demonstrated higher photodegradation efficiency. This superiority can be attributed to the synergistic action of adsorption and photocatalytic degradation working in tandem. This study prepared Cu doped CDs and elucidated the photocatalysis mechanism of methylene blue degradation by CDs. The photodegradation of organic dyes through CDs derived from waste CCA wood emerges as an eco-friendly, facile, and highly efficient method.