Properties and Novel Applications of Recycled Aggregates

The aggregates used in construction are the natural resource consumed the most in the world after air and water. Due to overexploitation, all environmental laws reward the use of recycled materials to guarantee the reduction of consumption of natural aggregates. The use of reclaimed aggregates, reused aggregates, and recycled aggregates increases sustainability in construction activities. Today, they are strategic materials in the manufacturing of green concrete and mortars and as road construction eco-efficient materials. In addition, the use of recycled aggregates from industrial or mining byproducts presents great potential in construction activities as recycled aggregates and/or supplementary cementitious materials. This Special Issue is open to new experiences in construction materials and/or works made with recycled aggregates

Comparative study of the production of cellulose nanofibers from agro-industrial waste streams of Salicornia ramosissima by acid and enzymatic treatment

The study of the suitability of two isolation processes to produce cellulose nanofibers (CNFs) from Salicornia ramosissima waste, with potential applicability as a reinforcing agent of polymeric composites was carried out. To separate the cellulose fibrils from the cell wall and obtain CNFs an alkaline treatment was applied followed by a bleaching treat-ment and, the insoluble residue was next hydrolyzed by either an acid treatment (AT) or an enzyme treatment (ET). SEM and TEM images indicated fiber exposure caused by both treatments. The diameter, length, aspect ratio, and polydispersity index, were measured for both CNFs. CNF (ET) showed high zeta potential values suggesting that ET produces more electrically stable and thinner nanofibers. The FTIR spectra revealed that both treatments effectively removed the amorphous components allowing the CNFs isolation, and XRD patterns evidenced the increase in the degree of crystallinity of both CNFs. Nonetheless, CNF(AT) presented a lower mechanical resistance due to its smaller particle size, compared to the CNF(ET). In summary, the (ET) could successfully isolate CNFs from the Salicornia waste, encouraging the use of this treatment, once when compared to (AT), it does not generate toxic residues, presents mild thermal conditions, and produces CNFs with higher-value applications.info:eu-repo/semantics/publishedVersio

Bark biorefinery: deconstruction and chemical potential of Eucalyptus globulus and Picea abies barks

Doutoramento em Engenharia Florestal e dos Recursos Naturais / Instituto Superior de Agronomia. Universidade de LisboaEucalyptus globulus and Picea abies barks are huge industrial residues with upgradable potential. This research thesis aims at further the knowledge on these barks envisaging production of biomaterials, building blocks, chemicals and fuels. Both industrial barks contained high wood and mineral extraneous contaminants, presenting higher extractives (10-20%) and ash (4-5%), but lower polysaccharides (52-61%) than their respective woods. E. globulus bark hemicelluloses (glucuronoxylan) and lignin (S/G=2.8, enriched in β-O-4’, 83% of all inter-unit linkages elucidated by 2D HSQC-NMR) were similar to those of wood, while P. abies bark differed substantially in hemicelluloses (pectin, higher arabinan, lower mannan) and lignin (γ-OH significant acetylation, presence of hydroxystilbenes glucosides as “nonconventional” true lignin monomers, adding to the canonical established monolignols precursors). The presence of glucosides in lignin was reported for the first time with positive ramifications regarding possible design and bioengineering of polymers with special attributes (hydrophilicity, bioactivity) Deconstruction pathways were tested considering the knowledge gathered. Bleached kraft pulp was produced from E. globulus bark due to previously determined appropriate physical and chemical characteristics. Hydrothermal pre-treatment tested decreased extractives content allowing for lower active alkali (15%) usage in pulping process (resulting in 40% yield) with subsequent bleached pulp and respective handsheets showing similar characteristics to those produced with E. globulus wood. Bark proved to be a possible fiber source feedstock for pulp and paper production. Crude extracts recovered with different solvents were analyzed for neutral monosaccharides and phenolic composition, antioxidant activity, antimicrobial and quorum-sensing potential. Polar extracts showed good or very good antioxidant activity. Gram positive and Candida strains had their growth highly impaired when exposed to n-hexane and ethanol extracts concentrations above 0.04 mg/mL. Extractive-free barks were autohydrolysed and the solid residues saccharified with commercial enzymes (Saczyme and Ultimase), resulting in xylooligosaccharides/arabinooligosaccharides enriched liquors from autohydrolysis, glucose rich streams from enzymatic saccharification and lignin enriched solid residues. This thesis evidences that these abundant industrial residues are interesting materials to be upgraded within a biorefinery concept of full biomass utilization with potential to generate several products and streams with different end-usesN/

Desconstrução de biomassa vegetal por auto-hidrólise

Mestrado em Química - Química Analítica e QualidadeThe search for better technologies for upgrading biomass wastes has received increasing attention in the recent years. Special consideration has to be given to the hemicellulosic fraction, one of the more challenging fractions. In this work, two biologically different waste materials were iorefinery concept: the materials derived from the forestry processing of the cypress cedar of Goa (Cupressus lusitanica Mill.), namely chips, bark, leaves and cones, and the wastes of the watermelon (Citrullus lanatus) industrial processing (rinds). The chemical composition of all materials was characterized taking special attention to the extractives content and to the structural polysaccharides and lignin and the autohydrolysis process was optimized aiming for the production of novel oligosaccharides. The autohydrolysis process presented a high selectivity towards hemicelluloses, yielding oligosaccharides in high concentrations, especially for the chips of cypress cedar of Goa. The oligosaccharides were characterized regarding their chemical composition and their stability under different temperature and pH values. Their potential industrial applications, namely for the food industry, are also presented and discussed. As a preliminary evaluation of the integrated upgrade of these materials, the use of biomass from cypress cedar of Goa as a source of essential oils and the digestibility of the cellulose present in the residual biomass derived from the autohydrolysis treatments as a source of glucose for fermentation were also tested and are discussed.A procura pelo melhor aproveitamento da biomassa vegetal tem vindo a despertar o interesse no uso racional de todos os seus componentes, tendo de se dar especial atenção à valorização das hemiceluloses, uma das frações mais desafiantes. Neste trabalho selecionaram-se dois resíduos vegetais, a biomassa do Cipreste-Português ou Falso-Cedro-do-Buçaco (Cupressus lusitanica Mill.) tendo-se estudado os seus principais constituintes (madeira, casca, folhas e gálbulas) e as cascas de melancia (Citrullus lanatus), principal resíduo da potencial utilização industrial deste fruto. Estudou-se a composição química dos diferentes materiais e otimizou-se o processo de auto-hidrólise para a produção de oligossacarídeos com potenciais novas funcionalidades. Os resultados demonstram a elevada seletividade do processo de auto-hidrólise para a remoção das hemiceluloses, principalmente para a estilha do Cipreste-Português, tendo-se obtido elevadas concentrações de oligossacarídeos. Os diferentes oligossacarídeos foram caracterizados relativamente à sua composição e estabilidade química sob diferentes temperaturas e valores de pH e discute-se a sua potencialidade para aplicações na indústria alimentar. Por forma a perspetivar uma valorização integrada dos materiais no conceito da biorrefinaria, estudou-se ainda a utilização da biomassa de Cipreste-Português como fonte de óleos essenciais e a digestibilidade enzimática da celulose presente na biomassa residual obtida do processo de auto-hidrólise como método de recuperação de glucose para fins fermentativos

From the kilns to the fair: producing building materials at Faragola and Canusium (northern Apulia, Italy)

Faragola and Canusium potters used Ca-rich clays—widely available nearby—for the production of build- ing materials. The clayey materials were used as received, before being fired in the local kilns at temperatures between 600 and ~1000 ° C. No technological distinctions were made in relation to the type of object to be produced (tile, brick, etc). The investigated productions are compositionally distinguish- able from both coarse wares for cooking and fine table ware produced in the same archaeological sites. A fine clayey ma- terial, very similar to that used for table ware, was supplied for the production of these building materials, which are chemi- cally, mineralogically and petrographically very similar among themselves. Hence, the Faragola and Canusium bricks and tiles cannot be easily discriminated but the presence/ absence of volcanites and volcanic glass represents an effec- tive discriminating factor, able to indicate areas of different supplies within two main deposits: the Pleistocene marine and alluvial terraced deposits, typical of northern Apulia

Microwave Pretreatment of Oil Palm Fronds for Enzymatic Saccharification

Oil palm frond (OPF) is distinguished to be one of the biomass resources in producing the alternative energy. Hence, in this paper, the practicability of the OPF to be used as biomass resource is studied by examining the reducing sugars composition available inside treated and untreated OPF biomass. Prepared sample of OPF have first gone under microwave and conventional pre-treatment followed by chemical treatment using NaOH. Chemical concentrations of 0 and 0.25N for the pre-treatment time of 2, 4, 8 and 12 minutes have been used. The morphological structure study is performed by using Scanning Electron Microscopy (SEM) and it certified that the surface treated with microwave assisted NaOH is more ruptured. Conventional pre-treatment is the most efficient compared to microwave pre-treatment at “low” setting with a temperature of less than 100°C by being able to liberate the highest amount of sugar yield of 32.31%. However, the reducing sugar yield still can be considered as low, even the filter paper can only liberate up to 28.94% of reducing sugar yield. Nevertheless, the pre-treated OPF still managed to yield more reducing sugars compared to untreated OPF which can only managed to yield sugars of 23.40%. Maximum saccharification yield of 32.31% for conventional heating and 26.20% for microwave pre-treatment is observed at optimal conditions of 0.5 g of dry biomass loading, 97.63 FPU/mL of enzyme loading, T.Reesei and 72 hour of incubation time. Keywords: Conventional pre-treatment; lignocellulosic; oil palm fronds;TricodermaReesei, Scanning Electron Microscopy (SE

Construction and Demolition Waste: Challenges and Opportunities

The current production and consumption models of building materials are causing severe environmental and social problems worldwide. In this sense, construction and demolition waste (C&DW) are part of the problem and can be part of the solution, particularly in developing countries where the construction industry is growing very rapidly. Although many efforts have been made by stakeholders to increase the use of C&DW in construction materials, articulated efforts are required at global, national, and local scales to develop truly sustainable construction sectors. Therefore, this e-book, which is based on the “Special Issue on Construction and Demolition Waste: Challenges and Opportunities”, is an effort to articulate knowledge on novel and innovative building materials using C&DW and management systems to develop circular economy models (CE) for the construction sector. In this e-book, it is concluded that even though the valorization of C&DW has been developed worldwide, more incentives need to be provided to really convert the local and national construction chains in sustainable sectors, which appropriate the circular economy for production and consumption systems that imrpove, at the least, efficiency in terms of materials, water and energy use

Participatory Bayesian modelling for sustainable and efficient river restoration projects: Feedback from the case study of the Gave de Pau River, Hautes-Pyrénées, France

Through the diversity of criteria and stakes, the uncertain nature of the entailed phenomena and the multi-scale aspects to be taken into account, a river restoration project can be considered as a complex problem. Integrative approaches and modelling tools are thus needed to help river managers make predictions on the evolution of hydromorphological, socio-economic, safety and ecological issues. Such approach can provide valuable information for handling long-term management plans that consider the interaction and the balance of stakeholders interests and river system functioning. In this paper, we present a probabilistic participatory modelling (PM) method that assesses the effects of given restoration actions, knowing the hydromorphological modifications that they may induce on the safety, ecological and socio-economic aspects with the help of local stakeholders through several workshops. To support this strategy, we used Bayesian networks (BNs) as modelling tools as their causal graphs can combine multidimensional knowledge and data from diverse natures. We introduce the causal graphs elaborated with the help of the stakeholders and convert it into BNs that can assist restoration decisions by considering the available decision and utility functions to provide guidance to decision-makers. This was applied to the “Lac des Gaves” reach in the Hautes-Pyrénées, France, a reach that has gone through severe sediment extractions for over 50 years. Each network represents possible restoration decisions linked to one of the observed issues. The paper demonstrates how BNs used as a decision support system (DSS) can help to assess the influence of given management strategies on the river system with the consideration of stakeholders’ knowledge and integration in all the modelling process

Intensification of Biomass Fractionation Processes Using Solid Catalysts

The development of selective and effective hemicellulose recovery and upgrade processes is one of the current major hurdles preventing the full onset of economic and environmentally sustainable biorefineries. In this work, four ion exchange resins (IERs) were characterized and evaluated as alternative catalysts, in order to explore the advantages of the acid-catalyzed processes for the i) direct hydrolysis of raw biomass and ii) the hydrolysis of oligosaccharides, both into monomeric hemicellulose-derived sugars. The hemicellulose hydrolysis using IERs was compared to the use of dilute sulfuric acid for diverse model feedstocks. For H2SO4 processes, xylan conversion into xylose reached 83.9% for Eucalyptus residues (ER), and 98.6% for Miscanthus. When using IERs, a superior or equivalent performance, namely, xylose yields of 93.7% (ER), and 91.3% (Miscanthus) were achieved when using Amberlyst 15. This was further validated for Wheat Straw (WS) that presented a complete hydrolysis of xylan into xylose, showing that IERs usage is an effective alternative for biomass deconstruction. In the two-step process, autohydrolysis and organosolv were compared as means to produced Xylo-oligosaccharides (XOS) both from ER and WS. Autohydrolysis presented higher XOS yields for both materials and these could be effectively hydrolyzed by IERs, namely Amberlite IR120 and specially Amberlyst 15, enabling to reach efficiencies superior to the H2SO4 catalyzed process. Catalyst reutilization is possible, and typically higher in autohydrolysis when compared to organosolv derived streams. This process was demonstrated to be able to be further intensified by the use of a continuous system, using raffinose as model oligosaccharide, for which a 50% hydrolysis was achieved for a low residence time (5 min) at 140ºC. Finally, the performance of the IERs is discussed based on their structures and properties and the impact of the amount of ash present in the feedstock.O desenvolvimento de processos seletivos e eficientes de recuperação de hemiceluloses é um dos principais obstáculos ao aparecimento de biorrefinarias sustentáveis a nível económico e ambiental. Neste trabalho, foram caracterizadas e avaliadas quatro resinas de troca iónica (IERs) como catalisadores ácidos alternativos, com o objetivo de explorar as vantagens dos processos ácidos para a i) hidrólise direta de biomassa e ii) hidrólise de oligossacáridos, ambas em monómeros de açúcares derivados de hemicelulose. A hidrólise da hemicelulose usando IERs foi comparada ao uso de ácido sulfúrico diluído para diversas matérias-primas. Nos processos catalisados por H2SO4, a conversão de xilano em xilose atingiu 83,9% para resíduos de eucalipto (ER) e 98,6%, para Miscanthus. As IERs, apresentaram um desempenho superior ou equivalente, com rendimentos de xilose de 93,7% (ER) e 91,3% (Miscanthus) usando Amberlyst 15. Isto foi posteriormente validado para a palha de trigo (WS) que apresentou hidrólise completa de xilano em xilose, demonstrando que as IERs são uma alternativa eficaz para desconstrução da biomassa. No processo de duas etapas, a auto-hidrólise e o organosolv foram comparados como processos de produção de Xilo-oligossacáridos (XOS) para ER e WS. A autohidrólise apresentou maiores rendimentos em XOS, para ambos os materiais. O XOS obtidos puderam ser eficazmente hidrolisados por IERs, nomeadamente Amberlite IR120 e principalmente Amberlyst 15, permitindo eficiências superiores ao processo catalisado por H2SO4. A reutilização do catalisador é possível, e normalmente é maior nos licores de auto-hidrólise em comparação com os licores organosolv. Este processo demonstrou poder ser ainda intensificado pelo uso de um sistema contínuo, utilizando rafinose como oligossacárido modelo, onde foi obtida uma hidrólise de 50% para um tempo de residência baixo (5 min) a 140ºC. Por fim, o desempenho das IERs é discutido com base nas suas estruturas e propriedades e no impacto da quantidade de cinza presente na matéria-prima

A Tight Interaction between the Native Seagrass Cymodocea nodosa and the Exotic Halophila stipulacea in the Aegean Sea Highlights Seagrass Holobiont Variations

Seagrasses harbour bacterial communities with which they constitute a functional unit called holobiont that responds as a whole to environmental changes. Epiphytic bacterial communities rapidly respond to both biotic and abiotic factors, potentially contributing to the host fitness. The Lessepsian migrant Halophila stipulacea has a high phenotypical plasticity and harbours a highly diverse epiphytic bacterial community, which could support its invasiveness in the Mediterranean Sea. The current study aimed to evaluate the Halophila/Cymodocea competition in the Aegean Sea by analysing each of the two seagrasses in a meadow zone where these intermingled, as well as in their monospecific zones, at two depths. Differences in holobionts were evaluated using seagrass descriptors (morphometric, biochemical, elemental, and isotopic composition) to assess host changes, and 16S rRNA gene to identify bacterial community structure and composition. An Indicator Species Index was used to identify bacteria significantly associated with each host. In mixed meadows, native C. nodosa was shown to be affected by the presence of exotic H. stipulacea, in terms of both plant descriptors and bacterial communities, while H. stipulacea responded only to environmental factors rather than C. nodosa proximity. This study provided evidence of the competitive advantage of H. stipulacea on C. nodosa in the Aegean Sea and suggests the possible use of associated bacterial communities as an ecological seagrass descriptor