The strive for utilization of green fillers in polymer composite has increased focus on application of natural biomass-based fillers. Biochar has garnered a lot of attention as a filler material and has the potential to replace conventionally used inorganic mineral fillers. Biochar is a carbon rich product obtained from thermochemical conversion of biomass in nitrogen environment. In this review, current studies dealing with incorporation of biochar in polymer matrices as a reinforcement and conductive filler were addressed. Each study mentioned here is nuanced, while addressing the same goal of utilization of biochar as a filler. In this review paper, an in-depth analysis of biochar and its structure is presented. The paper explored the various methods employed in fabrication of the biocomposites. A thorough review on the effect of addition of biochar on the overall composite properties showed immense promise in improving the overall composite properties. An analysis of the possible knowledge gaps was also done, and improvements were suggested. Through this study we tried to present the status of application of biochar as a filler material and its potential future applications.

Biomass is generally believed to be carbon neutral. However, recent studies have challenged the carbon neutrality hypothesis by introducing metric indicators to assess the global warming potential of biogenic CO₂ (GWP_bio). In this study we calculated the GWP_bio factors using a forest growth model and radiative forcing effects with a time horizon of 100 years and applied the factors to five life cycle assessment (LCA) case studies of bioproducts. The forest carbon change was also accounted for in the LCA studies. GWP_bio factors ranged from 0.13–0.32, indicating that biomass could be an attractive energy resource when compared with fossil fuels. As expected, short rotation and fast-growing biomass plantations produced low GWP_bio. Long-lived wood products also allowed more regrowth of biomass to be accounted as absorption of the CO₂ emission from biomass combustion. The LCA case studies showed that the total life cycle GHG emissions were closely related to GWP_bio and energy conversion efficiency. By considering the GWP_bio factors and the forest carbon change, the production of ethanol and bio-power appeared to have higher GHG emissions than petroleum-derived diesel at the highest GWP_bio.

This study aimed to evaluate the effect of styrene-assisted maleic anhydride-grafted poly(lactic acid) (PLA-g-St/MAH) on the interfacial properties of wood flour/poly(lactic acid) (PLA) bio-composites. PLA-g-St/MAH was synthesized by free-radical melt grafting using styrene as a comonomer and dicumyl peroxide as an initiator. The structure of PLA-g-St/MAH was characterized by Fourier transform infrared spectroscopy. Wood flour/PLA composites were prepared by compression molding using PLA-g-St/MAH as a compatibilizer. The effects of PLA-g-St/MAH on the rheological and mechanical properties, as well as on the fractured surface morphology of the composites were investigated. Results indicated that storage modulus, complex viscosity, equilibrium torque, and shear heat were significantly increased. The mechanical properties of the wood flour/PLA composites were also significantly increased after the addition of PLA-g-St/MAH. The maximum values were achieved at the loading rate of 3 wt % because of the improved interfacial adhesion between the wood flour and the PLA matrix.

This paper discusses the resource utilization of Fe-rich sludges generated as waste products from water treatment, hydrometallurgy, surface finishing, and dye chemical industries. Apart from the conventional landfill disposal of such sludges, the work focuses on sludge purification for new commercial products, including iron red/black dyes, an iron concentrate powder, a polyferric flocculant, a catalyst, and a magnetic adsorbent. Among such purifications, a new strategy was developed to recycle Fe-rich sludges for a new Fe/S-bearing flocculant. Given that Fe-rich sludges may contain rare and/or heavy metals, the purification of sludges as high-purity hematite nanoparticles and other valuable products is detailed as a new insight. Accordingly, the mechanisms for the phase transformation of Fe-bearing minerals and the purification of valuable Fe oxides are deeply considered. The work summarizes the pilot- and/or field-scale application for recycling of Fe-rich sludge and proposes the development of a new Fe/S flocculant and a high-purity hematite product.

This study evaluated the mechanical properties of hybrid (mixed-species) cross-laminated timber (CLT) panels made of low-value sugar maple (Acer saccharum) and white spruce (Picea glauca). The modulus of elasticity (MOE) of the laminations was measured with a nondestructive method. Three-layer hybrid CLT panels with layup combinations of sugar maple–white spruce–sugar maple and white spruce–sugar maple–white spruce were prepared to evaluate the effects of layups on the performance of the CLT samples. The mechanical properties of hybrid CLT panels were evaluated with different layups and both melamine- and resorcinol-based adhesives. Both long-span and short-span third-point bending tests were conducted to study the flexural and shear behavior of each CLT panel type. It was found that the influence of adhesive types was not significant. The mechanical properties of the hybrid CLT panels with sugar maple surface layers were improved significantly compared with those of the current standard layups. Both bending tests were simulated with finite-element analysis based on measured and reference material properties. The simulated results of each case were in good agreement with the test results.