Brazilian Amazonian palm-stem types and uses: a review

ABSTRACT Palms may be an important source of renewable raw material to replace wood, however, the uses of the stems of native species of the Brazil are known only at the local or regional level. We carried out a literature review on the traditional knowledge of the uses of the stems of palm species native to the Amazon biome in Brazil, and related the types of uses with morphological characteristics of the stems. The review resulted in information on 45 species with solitary or cespitose stems, and six stem-size types: tall (15 species), medium-short (3), medium (5), small (17), acaulescent (1) and climbing (4). We found 80 indications of stem use in seven categories and 14 subcategories. A similarity analysis showed that, in general, tall, medium-short, medium, small (≥ 10 cm in diameter) and climbing stem types, solitary or cespitous, are used for construction, furniture, handicrafts, utensils, tools and musical instruments. Only small stems (< 10 cm diameter) are used to manufacture weapons for hunting and fishing, and climbing stems are used in the manufacture of ropes. Stems of Socratea exorrhiza, Euterpe oleracea and Desmoncus polyacanthos are the most frequently used to meet subsistence needs in traditional communities in the Brazilian Amazon. Our findings indicate that there is a potential for use of several native palm stems as sources for alternative materials in the manufacture industry and as sustainable income sources for Amazonian communities.

Ethanol Dehydrogenation to Acetaldehyde over Co@N-Doped Carbon

Cobalt and nitrogen co-doped carbon materials (Co@CN) have recently attracted significant attention as highly efficient noble-metal-free catalysts exhibiting a large application range. In a similar research interest, and taking into account the ever-increasing importance of bioethanol as a renewable raw material, here, we report the results on ethanol dehydrogenation to acetaldehyde over Co@NC catalysts. The catalyst samples were synthesized by a variety of affordable techniques, ensuring generation of various types of Co species incorporated in carbon, such as subnanosized cobalt sites and nano-sized particles of metallic cobalt and cobalt oxides. The catalytic activity was tested under both oxidative and non-oxidative gas-phase conditions at 200–450 °C using a fixed-bed flow reactor. The non-oxidative conditions proved to be much more preferable for the target reaction, competing, however, with ethanol dehydration to ethylene. Under specified reaction conditions, ethanol conversion achieved a level of 66% with 84% selectivity to acetaldehyde at 400 °C. The presence of molecular oxygen in the feed led mainly to deep oxidation of ethanol to COx, giving acetaldehyde in a comparatively low yield. The potential contribution of carbon itself and supported cobalt forms to the observed reaction pathways is discussed.

Life cycle assessment of bioenergy production from macroalgae : A review

The sustainability integration to achieve circular economy pressures the development of renewable raw material and bioenergy sources, including marine biomass such as macroalgae. The consideration of sustainable conversion technology for bioenergy from macroalgae is critically highlighted. Various studies have been emphasized that life cycle assessment (LCA) can be applied to assess the efficacy and environmental aspects of bioenergy production from cradle-to-grave. This systematic review attempts to critically evaluate the development of LCA studies on macroalgae valorisation for bioenergy. Several online databases (i.e., Science Direct, Wiley Online Library, Springer, DOAJ, and MDPI) were used to collect the relevant articles. Then, PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) method has been selected to screen the most recent research articles (from January 2011 to June 2021) published in peer-reviewed international journals. The studies presented the development, opportunities, challenges, and future research for the commercialization of macroalgae as a sustainable feedstock for bioenergy.

Lignin-Based High-Performance Fibers by Textile Spinning Techniques

As a major component of lignocellulosic biomass, lignin is one of the largest natural resources of biopolymers and, thus, an abundant and renewable raw material for products, such as high-performance fibers for industrial applications. Direct conversion of lignin has long been investigated, but the fiber spinning process for lignin is difficult and the obtained fibers exhibit unsatisfactory mechanical performance mainly due to the amorphous chemical structure, low molecular weight of lignin, and broad molecular weight distribution. Therefore, different textile spinning techniques, modifications of lignin, and incorporation of lignin into polymers have been and are being developed to increase lignin’s spinnability and compatibility with existing materials to yield fibers with better mechanical performance. This review presents the latest advances in the textile fabrication techniques, modified lignin-based high-performance fibers, and their potential in the enhancement of the mechanical performance.

Recent Tendencies in Waste-Based Aggregates in Concrete Production

The development of construction and the growing popularity of concrete as a building material cause a continuous increase in the demand for non-renewable raw material such as aggregate. This paper aims to analyse the possibility of using various alternative aggregates for the production of concrete. In the first part of article a detailed analysis of the European aggregate production has thus been carried out and the requirements for concrete aggregates according to European Standards have been also presented. One of the goals of sustainable waste management is to reduce landfills by finding new ways to reuse and disposing waste. Therefore in the second part of article the waste-based aggregates have been analysed. Moreover, various types of alternative aggregates such as recycled and manufactured aggregates are discussed in detail. The article presents also the properties of selected alternative aggregates with a proposal of pre-treatment. Based on the presented analyses it can be concluded that each new waste that is sourced as aggregate in concrete should undergo detailed testing because of the different chemical and mechanical properties of various waste aggregates. Hence, specific research for each waste should be undertaken.

Biodegradable Plastics from Renewable Raw Materials

Fossil oil prices are soaring steeply due to the depleting petroleum raw materials. Extensive research has been carried out around the globe to develop efficient processes that can replace oil-derived polymers (conventional plastic) with bio-based polymers that originate from renewable resources. Fossil-oil based plastic products take decades to degrade, leading to the unwanted accumulation of plastic waste that can be seen all around. Further, greenhouse gases emission occurs during the production and destruction of synthetic plastic. Therefore, plastic waste has become a massive threat to the biosphere and needs to be addressed immediately. To overcome this issue, a new type of plastic can be produced from bio-resources that can fulfill even the energy demand in today's world. This new form of plastic must be accommodated fast in daily life, considering the range of applications of plastics. Biodegradable plastics made from renewable raw materials can retain all the benefits of petroleum-based plastic without having any negative impacts on the environment. Bioplastics are not toxic in nature and can easily decay back into carbon dioxide via degradation. The products made from bioplastics may be commercialized, considering their superior properties over conventional plastic. The discovery and implementation of plastic made from renewable raw material resources could be a giant leap into the sustainable future.

Use of bacterial cellulose in the textile industry and the wettability challenge - a review

Bacterial cellulose (BC) has been studied as an alternative material in several segments of the food, pharmaceutical, materials and textile industries. The importance of BC is linked to sustainability goals, since it is an easily degradable biomaterial of low toxicity to the environment and is a renewable raw material. For use in the textile area, bacterial cellulose has attracted great interest from researchers, but it presents some challenges, notably hydrophilicity due to its porous structure. This bibliometric review article gathers studies and methods related to minimizing the hydrophilicity of bacterial cellulose in order to expand its applicability in the textile industry. The databases consulted were ScienceDirect, ProQuest and Web of Science, the documents investigated were scientific articles and the time period investigated was between 2015 and 2021. The discussion is focused on the applicability of BC in the textile industry, highlighting the research needs, especially with regard to reducing wettability.

A Review on the Lignin Biopolymer and Its Integration in the Elaboration of Sustainable Materials

Lignin is one of the wood and plant cell wall components that is available in large quantities in nature. Its polyphenolic chemical structure has been of interest for valorization and industrial application studies. Lignin can be obtained from wood by various delignification chemical processes, which give it a structure and specific properties that will depend on the plant species. Due to the versatility and chemical diversity of lignin, the chemical industry has focused on its use as a viable alternative of renewable raw material for the synthesis of new and sustainable biomaterials. However, its structure is complex and difficult to characterize, presenting some obstacles to be integrated into mixtures for the development of polymers, fibers, and other materials. The objective of this review is to present a background of the structure, biosynthesis, and the main mechanisms of lignin recovery from chemical processes (sulfite and kraft) and sulfur-free processes (organosolv) and describe the different forms of integration of this biopolymer in the synthesis of sustainable materials. Among these applications are phenolic adhesive resins, formaldehyde-free resins, epoxy resins, polyurethane foams, carbon fibers, hydrogels, and 3D printed composites.