Sustainable production of renewable energy is being hotly debated globally since it is increasingly understood that first generation biofuels, primarily produced from food crops and mostly oil seeds ...are limited in their ability to achieve targets for biofuel production, climate change mitigation and economic growth. These concerns have increased the interest in developing second generation biofuels produced from non-food feedstocks such as microalgae, which potentially offer greatest opportunities in the longer term. This paper reviews the current status of microalgae use for biodiesel production, including their cultivation, harvesting, and processing. The microalgae species most used for biodiesel production are presented and their main advantages described in comparison with other available biodiesel feedstocks. The various aspects associated with the design of microalgae production units are described, giving an overview of the current state of development of algae cultivation systems (photo-bioreactors and open ponds). Other potential applications and products from microalgae are also presented such as for biological sequestration of CO
2, wastewater treatment, in human health, as food additive, and for aquaculture.
In spite of raising awareness of the environmental impacts associated to the production and utilization of plastics, in many situations, the use of plastics is advantageous, and options are still ...unavailable or under development, representing an opportunity to develop more sustainable options, such as less energy intensive solutions. In this work, the LCA methodology is used to evaluate the environmental impacts of boxes, bowls and plates produced using Areca palm (Areca catechu) sheath, a waste material common in southern India. The inventory is a combination of primary data from a company in India, complemented with secondary data from the Ecoinvent v2.1 (Simapro V7.3). Results show that the main contributors to the potential environmental impact categories and the most energy intensive life cycle steps, are transportation, shipping and electricity generation. Carbon footprints of 1180, 1033 and 1090 kg CO2eq/ton were obtained for Areca boxes, plates and bowls, respectively. Plates made from Areca palm sheath have lower environmental impacts than plastic plates, except in the ozone layer depletion and terrestrial toxicity impact categories.
► Microalgae Scenedesmus obliquus (So) cultivated in a synthetic brewery effluent. ► Growth of So and reduction of COD, of total nitrogen and of total carbon. ► Influence of light/dark photoperiod, ...light intensity and culture aeration. ► Most adequate operating conditions for the So cultivation in this effluent.
This work analyses the potential of using microalgae Scenedesmus obliquus (So) for a brewery wastewater treatment and biomass production. The chemical oxygen demand (COD), total nitrogen (TN) and total carbon (TC) was followed in time, and the influence of light exposure, light intensity and culture aeration was studied. Results show that the most adequate conditions for cultivating So in this effluent are the aerated cultures, exposed to a 12h period of daily light, at 12000Lux intensity. At these conditions it is obtained a maximum of 0.9g of dry biomass per liter of culture, after 9days, for a maximum reduction of 57.5% and 20.8% of COD and TN, respectively, after 14days, and 56.9% of TC, after 13days, corresponding to the final values of 1692mg O2/L COD, 47mg N/L TN, and 1mg C/L TC.
Adding value to agro-industrial residues is becoming increasingly important, satisfying needs to promote resources’ use efficiency and a more sustainable and circular economy. This work performs a ...parametric and kinetic study of enzymatic esterification of lard and tallow with high acidity, obtained by the rendering of slaughter by-products, allowing their use as a feed ingredient and increasing their market value. After an initial analysis of potential enzyme candidates, a Candida antarctica lipase B was selected as a biocatalyst for converting free fatty acids (FFA) to esters, using excess ethanol as the reagent. Results show that the fat acidity can be reduced by at least 67% in up to 3 h of reaction time at 45 °C, using the mass ratios of 3.25 ethanol/FFA and 0.0060 enzyme/fat. Kinetic modelling shows an irreversible second-order rate law, function of FFA, and ethanol concentration better fitting the experimental results. Activation energy is 54.7 kJ/mol and pre-exponential factor is 4.6 × 106 L mol−1 min−1.
This work evaluates the use of spent coffee grounds (SCG) for biodiesel production. The SCG were characterized for their moisture content (12.1 wt%), total carbon (TC) and total nitrogen (TN) (52.2 ...and 2.1 wt% respectively), cellulose and total lignin contents (33.6 wt% and 13.8 wt% respectively), carbon/nitrogen mass ratio (C/N = 24.8) and higher heating value (HHV, of 19.3 MJ/kg). For extracting the oil from the SCG, several solvents were tested at different contact times: hexane, ethanol, isopropanol, heptane and a mixture of hexane/isopropanol in the proportions of 50:50; 60:40; 70:30 and 80:20 (vol/vol). Results revealed an oil content ranging from 6.3 to 28.3 wt%, depending on the extraction conditions. For example, using hexane/isopropanol (50:50, vol/vol) a 21.5 wt% of oil recovery was obtained after 3 h of contact time, while using isopropanol a 21.0 wt% of oil recovery was obtained in 6.8 h, but at higher operating cost, considering the energy and solvent consumption. Regarding the oil characterization the following parameters can be highlighted: HHV of 36.4 MJ/kg, iodine value of 54.4 (g I2)/(100 g oil), water content of 2004 ppm and acid value of 118.4 (mg KOH)/(g oil). Finally, the possibility of using the recovered coffee oil for biodiesel production was evaluated. In this regard it was performed the oil esterification in three consecutive steps (using 1% of H2SO4 and 40% of methanol for 2 h of reaction time at 60 °C and 500 rpm) followed by one transesterification step (1% of NaOH and 40 % of methanol during a 2 h reaction time at 60 °C and 500 rpm). The resulting biodiesel was characterized for its acid value, density, viscosity at 40 °C, iodine value and esters content (65.7 to 72.9 %), of which only the iodine value of 26 and 58.4 (g I2)/(100 g biodiesel) was within the NP EN14214:2009 standard limits. The reaction yield varied between 58.8 and 62.2 wt%. Results suggest the need for a further process optimization in order to obtain a biodiesel complying with this standard quality requirements.
The World pandemic situation that started in 2020 brought important limitations to live events. In spite of the fast response provided by the scientific community, with researchers from all over the ...World committed to the development of vaccines to prevent the dissemination and effects of the corona virus, in 2021 it was not yet possible to organize the 8th International Conference on Energy and Environment Research (ICEER) under live mode. Therefore, the ICEER 2021 occurred online for the second consecutive year, from 13–16 September 2021. The Authors, Participants and the Conference organization understood how important it is to discuss matters related to Energy and the Environment Research, as it was demonstrated by the huge changes introduced by travel and work limitations. Not only the energy consumption was affected during the pandemic, but also the environment was positively impacted by the reduction of human individual travel, both for working and for amusement purposes. These facts highlighted even more the importance of the development and use of energy sources and systems that are reliable, affordable and, above all, environment friendly, towards Sustainable Development, which motivated the theme adopted for the current edition of ICEER 2021: “Developing the World in 2021 with clean and safe energy”. The ICEER 2021 recovered some participants who preferred the live version but were committed not to give up on their research in these important topics, and the full three working days demonstrated the resilience of this community. This editorial paper summarizes the ICEER 2021, briefly reporting the main conclusions and the most impacting sessions, presentations and interventions that allowed to strengthen the interaction among experts and young researchers in the energy and environment field.
The objective of this work was to find the ideal pretreatment conditions with high efficiency to obtain a hydrolyzate rich in fermentable sugars and low possible inhibitors levels. Thus, it was ...applied diluted phosphoric acid to pretreat the sugarcane biomass. Through a Central Composite Design, it was evaluated the influence of temperature, operating time and acid concentration. The pretreatment efficiency was verified by the concentration of total monosaccharides in the liquid fraction after the reaction. The phosphoric acid concentration of 4.95% at 80 °C, during 375 min, resulted in a hemicellulosic hydrolyzate with the highest concentration of fermentable sugars (saccharification greater than 99%), with the absence of HMF and furfural, and relatively low amounts of acetic acid.
Correction for 'Syngas production by bi-reforming methane on an Ni-K-promoted catalyst using hydrotalcites and filamentous carbon as a support material' by Adelino F. Cunha
et al.
,
RSC Adv.
, 2020,
...10
, 21158-21173, DOI:
10.1039/D0RA03264F
.
The 6th edition of the International Conference on Energy and Environment Research, ICEER 2019, took place in the end of July 2019, at the University of Aveiro, Portugal. With most of the ...participants coming from academia, and a few from the professional field, ICEER series is still growing and attracting increased interest. Energy production, distribution and use are fundamental for the Sustainable Development of nations, showing a clear link between the energy and environment issues. Nevertheless, these matters are frequently dealt with separately, reflecting the way they are taught, and causing strong negative impacts, and hindering progress. With a growing trend in circular economy models applied to common goods production and commercialization, ICEER 2019 had as focus theme the challenges posed by energy and environment research in a circular economy-based model.
This paper presents the main achievements and conclusions of ICEER 2019 participants, through their research in the fields of energy and environment, including a brief analysis of the current requirements of Education on Sustainable Development applied to the modern technological curricula.
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