Volume 14 Issue 1

The feasibility of solid-state fermentation was studied for sea buckthorn seed residues (SBSR). Effects of different fermentation parameters were evaluated regarding the levels of biomass and compounds in aqueous and non-aqueous extracts. In the latent and logarithmic phases of fermentation, the total phenols and flavonoids were increased. The microbes’ decomposition on fibrous matter allowed the active components to be fully extracted. The changes of total sugar levels had a contrary trend with the changes of total phenol and flavonoid contents. The monosaccharide and polypeptide contents decreased dramatically and then kept steady along with the fermentation. Unsuitable environments led to weak growth of the fungi, limited enzyme contents, low enzyme activity, and a poor degradation of the substrates. The active compounds considered in the study were protected, and the contents reached a maximum under conditions that were usually not suitable for the fungal growth. The chemical structure was another important factor influencing the content and stability of the compounds. The content of procyanidins decreased dramatically because of its sensitivity to heat and alkaline environments. Antioxidant abilities of SBSR extracts, both aqueous and non-aqueous, increased after fermentation. These results reflected a possibility to recycle SBSR for further use in the food industry.

Wood chips screening rejects (WCSR) are mainly composed of sawdust, bark specks, and wood pins generated from cutting and chipping processes, as well as solid waste from pulping processes. It can be modified so that it can better serve as effective sorbents for wastewater treatment. In this study, three WCSR based sorbents were prepared by nitric acid, phosphoric acid, and sodium hydroxide treatment, respectively. The purpose of the three treatments on WCSR was to increase the specific area of WCSR, which is very essential to a high sorbent performance. It was found that nitric acid, phosphoric acid, and sodium hydroxide can be efficient modifiers of WCSR according to the results from SEM and specific area analyses, compared with those of the controls. The FT-IR results also supported the findings stated above. Thermogravimetric (TGA) analysis and X-ray diffraction (XRD) analyses were also applied to characterize the prepared sorbents. WCSR sorbents modified by the three treatments exhibited higher methylene blue adsorption values compared with that of the control sample, and that the WCSR-HNO3 sorbent achieved the highest MB adsorption value among others, thanks to the strong acidic properties and high reactivity of HNO3 with WCSR. The study paves a potential way to convert WCSR into effective sorbents by acid and alkali treatment.

Hardwood is currently underestimated with respect to its utilisation and its value creation potential. Due to changes in forest management in various countries, hardwood resources will become more important. However, solid hardwood (SH) production capacities, mainly structured as small to medium-sized enterprises (SME), are dropping or have dropped already because of changes in the wood products market. Enhancing the SH sector, the foundation of products, processes, and technology must be better understood. To support the SME SH business, the approach used here focuses on manufacturing processes of the first and secondary downstream industry. A multi-step Quality Function Deployment has been developed to match the manufacturing process with the product architecture, and a Process-Technology Matrix has been added to visualize the influence of technology on the manufacturing process. Both have been applied on three chosen hardwood products which are solid wood panel, parquet, and glued-laminated timber. The main contribution of the paper is a conceptual consideration with a conceptual framework rather than providing comprehensive solutions. Optimization potential exists within the SH manufacturing chain based on alternative the combinations of manufacturing processes and applied technologies.

Compared with conventional chemical deinking, enzymatic deinking is a more environmentally compatible alternative for processing recovered paper. In this study, a bacterial isolate identified as Achromobacter xylosoxidans (designated as L2) was found to be a promising candidate for a paper deinking process. It showed endoglucanase, β-glucosidase, endoxylanases, and filter paper degrading activities (FPase) with the maximal values of 2.60, 2.57, 3.08, and 24.58 U/mL, respectively. The optimal temperature and pH for FPase were determined to be 44 °C and pH 7.6. After two days of incubation with L2 at 130 rpm and 30 °C, the waste newspaper strips (0.5 cm × 5 cm) were disintegrated to debris with the average size of 3.5 mm (while that of the untreated without inoculation of L2 was 5.7 mm). The final brightness of the regenerated handsheets after incubation with L2 increased 3.7 units (31.4% ISO). The isolate and its complete lignocellulosic enzymes could be applied as deinking agents in the recycling of waste paper.

The exact mechanism behind the disintegration of chemical pulp fiber into cellulose nanofibers is poorly understood. In this study, samples were subjected to various homogenization cycles, indicating that the mechanism is a stepwise process. In the earlier stages of the mechanical process, a large amount of macrofibrils were created as the larger structures disappeared. Upon mechanical treatment these macrofibrils disappeared despite the increasing yield of cellulose nanofibers. The proposed model expands the understanding of the disintegration pathway and may provide additional insight as to how wood cells are converted into microfibrils.

The use of different mineral material types and contents in medium density fiberboard (MDF) production was investigated. Three different minerals (sepiolite, dolomite, and perlite) and five different ratios (3%, 6%, 9%, 12%, and 15%) were used according to the oven-dry wood fiber weight. These minerals were homogeneously added as powder between the wood fibers. Some physical, mechanical, limit oxygen index (LOI), and thermogravimetric analysis (TGA) tests of the boards were conducted. The mineral fillers negatively affected the physical properties such as water absorption (WA), thickness swelling (ThS), and mechanical properties such as modulus of rupture (MOR), modulus of elasticity (MOE), and internal bond (IB). However, LOI and TGA test results showed a positive effect on combustion resistance depending on the type and rate of mineral fillers.

This manuscript provides a brief review about chemical and biological agents used to bioremediate treated wood waste. Wood preservatives have been used to increase wood’s useful life, because any species is subject to decay. Studies indicate that the disposal of treated wood after its service has drawn concern and scrutiny. Practices have included disposal in landfills or construction sites as well as destruction by burning, so it is apparent that more environmentally friendly options are needed. To mitigate these problems, acidic agents, fungi, and bacteria can be used as alternatives to remove heavy metals. At optimum temperature and concentration, acids play a major role in the removal process. The process is enhanced when a bioremediation technique is used after chemical extraction.  In fact, bioremediation has been shown to be a remarkable technique for recovering copper, arsenic, creosote, and other compounds. The major drawback is the extensive duration of fungal activity for release of heavy metals.

The separation of lignin from the black liquor generated during alkaline pulping is reviewed in this article with an emphasis on chemistry. Based on published accounts, the precipitation of lignin from spent pulping liquor by addition of acids can be understood based on dissociation equilibria of weak acid groups, which affects the solubility behavior of lignin-related chemical species. Solubility issues also govern lignin separation technologies based on ultrafiltration membranes; reduction in membrane permeability is often affected by conditions leading to decreased solubility of lignin decomposition products and the presence of colloidal matter. Advances in understanding of such phenomena have potential to enable higher-value uses of black liquor components, including biorefinery options, alternative ways to recover the chemicals used to cook pulp, and debottlenecking of kraft recovery processes.

The crises in global energy and environmental degradation, combined with developing consumer demands have stimulated researchers’ interest in inexpensive, environmentally friendly functional materials. Based on a projected annual production of palm oil in Malaysia of over 15.4 million metric tons by 2020, it is estimated that about 46.6 tons of lignocellulosic wastes will be generated. Transforming these wastes into wealth could be integrated into a global paradigm shift towards sustainable development. Carbon-based nanomaterials including graphene, graphene oxide, carbon nanotubes, epoxy nanocomposites, porous carbon nanoparticles, and nanoactivated carbons-filled-epoxy nanocomposites have been produced from these by-product materials using methods such as vapour deposition, pyrolysis, hydrolysis, chemical composition, high energy ball milling, and solution casting. This review attempts to present the current developments on renewable carbon nanomaterials derived from oil palm-based precursors with some insights given on their potential applications as energy storage materials.

Forming an adhesive joint between two wet cellulose surfaces before a drying step is important when manufacturing paper, foams, aerogels, other novel materials from wood pulp fibers, and various types of nanocellulose. This paper reviews the literature with an emphasis on the role of adhesive polymers on wet cellulose adhesion. Linkages between the organization of adhesives between the bonded surfaces and the strength of joints are emphasized. Relevant adhesion results from the surface forces apparatus, colloidal probe atomic force microscopy, paper wet-web strength, and wet-peeling of laminated regenerated cellulose membranes are considered.