Volume 15 Issue 4

In the continual desire to reduce the environmental footprints of human activities, research efforts to provide cleaner energy is increasingly becoming vital. The effect of climate change on present and future existence, sustainable processes, and utilizations of renewable resources have been active topics within international discourse. In order to reduce the greenhouse gases emissions from traditional materials and processes, there has been a shift to more environmental friendly alternatives. The conversion of biomass to bioenergy, including biofuels has been considered to contribute to the future of climate change mitigation, although there are concerns about carbon balance from forest utilization. Bioenergy accounts for more than one-third of all energy used in Sweden and biomass has provided about 60% of the fuel for district heating. Apart from heat and electricity supply, the transport sector, with about 30% of global energy use, has a significant role in a sustainable bioenergy system. This review presents the state of the art in the Swedish bioenergy sector based on literature and Swedish Energy Agency’s current statistics. The review also discusses the overall bioenergy production and utilization in different sectors in Sweden. The current potential, challenges, and environmental considerations of bioenergy production are also discussed.

In recent years, India has emerged as a promising industrial hub. It has a cluster of textile, dyeing, and printing industries. The adjoining rivers/water bodies receive mostly untreated discharge from these industries. Textile industrial effluent contains various contaminants (dyes, heavy metals, toxicants, and other organic/inorganic dissolved solids) that alter the physico-chemical properties of adjoining land and waterbodies in which it is discharged, thereby degrading the water quality and subsequently affecting the landscapes in the vicinity. This ultimately affects the flora and fauna of the locale and has adverse effects on human health. Out of the total dyes (approximately 10,000 dyes) exploited in the textile dyeing and printing units, azo dyes possess a complex structure and are synthetic in origin. They contribute nearly 70% to the total effluent discharge. Biological processes are based on the ability of inhabiting indigenous microorganisms in these contaminated environments to tolerate, resist, decolorize/degrade, and mitigate the recalcitrant compounds. Exploring microbes with higher efficacy of azo dye degradation can reduce the amount of chemical discharged from the process. The present review explores the potential of microbial diversity for the development of an effective bioremediation approach. The review also includes the impact of azo dyes on the flora and fauna, as well as conventional and microbe-assisted nanoparticle technology for treatment of the textile wastewater targeting the degradation of dye contaminants.

It is critical to develop sustainable, effective, and innovative technologies for society, particularly for processing of biomass, so that the green/ sustainable advantages can be extended to the final products. This review examined two-step biological-mechanical defiberization of lignocellulosic biomass to produce fibers. Two biological pretreatment methods of fungi and enzymes were mainly introduced, with particular focus on the energy consumption. Potential application methods, advantages, disadvantages, process economics, and future prospects of two biological pretreatment methods were considered to derive a complete road map for the proposed process. With the help of biological pretreatment, the mechanical pulping production could not only improve the paper strength, but also decrease energy consumption at about 40%. This process fits well with the green/sustainable strategy to produce lignocellulosic fibers with reasonable quality while having minimal environmental impact.

In the past decade, the Chinese paper industry, which is highly polluting and energy intensive, has shown overall increases in production, sales, income, and profit, although the growth rate has declined. Overall, China’s paper industry exhibits small-scale and scattered distribution, characterized by continuous overcapacity and outdated technical knowledge. This has inevitably resulted in a variety of serious environmental problems during its development. Owing to the environmental problems resulting from the development of the paper industry, various environmental regulatory policies and measures have been adopted in China, mainly command-and-control, market-based, and voluntary policies and measures. This study identifies and analyzes particular issues inherent to China’s environmental regulatory policies and measures regarding the paper industry and proposed policy suggestions for improving the environmental regulation of China’s paper industry.

The color, texture, and natural defects of wood are important factors affecting its commercial value. Change of wood’s surface color is a primary way to improve its value. This study analyzes and summarizes the development status and existing problems of the traditional wood dyeing process and induced discoloration process. It is proposed that color improvement with photonic crystal structure color is a clean and pollution-free ecological biomimetic coloring technology. Its research status in the fields of fiber, fabric, wood, wood-based panel surface color improvement, new coatings for wood, and lignocellulose nanocrystalline structure color film are reviewed. The following aspects were studied: 1) construction and mechanistic study of the wood surface structure color film, 2) light response and interface mechanistic study of the wood surface structure color film, 3) large-scale application technology study of the wood surface biomimetic structure color film, and 4) preparation and functional development of structural color films of lignocellulose nanocrystal.

Oil palm biomass is readily available in Malaysia. However, its high lignin content makes it undesirable for further processing. Pretreatment is employed to reduce the amount of lignin. Many resources exist on pretreatment methods for lignocellulosic biomass, but there are few articles specifically on oil palm biomass. Therefore, this review focuses on pretreatment methods for oil palm biomass, comparing their main strengths and limitations. Furthermore, this review tabulates different pretreatment conditions utilized, combinations of pretreatment methods, the resulting yields, and the potential applicability in producing value-added products. Because the main limitation of pretreatment is the formation of toxic compounds such as furfural and hydroxymethylfurfural, this review also discusses chemical detoxification methods for oil palm biomass residues. According to this review, among all types of oil palm biomass, oil palm empty fruit brunch is the most widely studied, and alkaline pretreatment is the most popular of all pretreatment methods. Combination of pretreatment methods is suitable for biomass with greater lignin content, to increase delignification efficiency. Furthermore, a combination of overliming and activated carbon treatment removes the maximum amount of toxic by-products.

This review considers three aspects of the weathering of wood – natural weathering, accelerated weathering, and simulated weathering. Natural weathering begins when unprotected wood, such as an unpainted board, is exposed to cycles of solar radiation and rain. Unpainted barns and fenceposts take on a gray coloration and their surfaces may become rough, loosened, or checked with the passage of time. The underlying causes of such changes involve ultraviolet light, the effects of cyclic wetting and drying, and the action of certain fungi. Accelerated weathering tests have been used not only to evaluate the effectiveness of varnishes and paints, but also to aid in the understanding of factors affecting natural weathering. Simulated weathering usually has the goal of quickly and conveniently changing the appearance of fresh wood to give the impression of weathering. This might increase its appeal for various decorative purposes. Information about simulated weathering, though largely absent from the scientific literature, is very much alive in social media. This article considers the science behind all three types of weathering in the light of published accounts.

Lignocellulosic biomass is a class of sustainable material that can be utilized as a raw feedstock in biofuel and chemical production. However, the complex matrix structure of lignocellulosic materials complicates conversion processes, such as enzymatic hydrolysis. Therefore, an efficient pretreatment process is required to disrupt the plant cell wall structure and maximize the recovery of valuable soluble components from lignocellulosic biomass during hydrolysis. In addition, an effective pretreatment method should use the minimum necessary amounts of energy and chemicals to minimize the cost of the end product. Further, it should reduce the formation of inhibitory compounds that affect enzymes and microorganisms during hydrolysis and fermentation, and it should be applicable to a wide variety of feedstocks. The research presented in this review has highlighted the pros and cons of the current technologies employed in pretreatment processes. Further study should be done to optimize and improve these technologies to enhance the efficiency of the production of biofuels and other valuable components.