Experimental and Techno-Economic Study on the Use of Microalgae for Paper Industry Effluents Remediation

Humanity is facing some major global threats, namely lack of environmental sustainability, the energy crisis associated with the unsustainable reliance on fossil fuels, and water scarcity, which will be exacerbated with the rapid growth of urban areas. Researchers have drawn their attention to microalgae, photosynthetic microorganisms known for their environmental applications, such as wastewater remediation and lipids accumulation, to produce third-generation biofuels to solve some of these major issues. Considering this dual role, this study evaluated the potential of the microalga Chlorella vulgaris on nutrient removal from a paper industry effluent and bioenergy production. Firstly, experiments were performed to assess the potential of this microalga to: (i) successfully grow in different concentrations of a paper industry effluent (20% to 100%); and (ii) treat the industrial effluent, reducing phosphorus concentrations to values below the accepted legal limits. Then, a techno-economic assessment was performed to study the viability of a C. vulgaris biorefinery targeting the remediation of a paper industry effluent and bioenergy production. The results have shown that C. vulgaris was able to successfully grow and treat the paper industry effluent. Under these conditions, average biomass productivities determined for this microalga ranged between 15.5 +/- 0.5 and 26 +/- 1 mg dry weight (DW) L-1 d(-1), with maximum biomass concentrations reaching values between 337 +/- 9 and 495 +/- 25 mg DW L-1 d(-1). Moreover, final phosphorus concentrations ranged between 0.12 +/- 0.01 and 0.5 +/- 0.3 mg P L-1, values below the legal limits imposed by the Portuguese Environment Agency on the paper industry. Regarding the proposal of a microalgal biorefinery for the bioremediation of paper industry effluents with bioenergy production, the techno-economic study demonstrated that six of the seven studied scenarios resulted in an economically-viable infrastructure. The highest net present value (15.4 million euros) and lowest discounted payback period (13 years) were determined for Scenario 3, which assumed a photosynthetic efficiency of 3%, a lipids extraction efficiency of 75%, and an anaerobic digestion efficiency of 45%. Therefore, it was possible to conclude that besides being economically viable, the proposed biorefinery presents several environmental benefits: (i) the remediation of an industrial effluent; (ii) CO2 uptake for microalgal growth, which contributes to a reduction in greenhouse gases emissions; (iii) production of clean and renewable energy; (iv) soil regeneration; and (v) promotion of a circular economy

Cacao families and parents selected as resistant to natural infection of Moniliophthora perniciosa

The known sources of resistance to witches' broom (WB), a severe disease of cacao, are limited. Aiming to identify families and parents resistant to Moniliophthora perniciosa, a population of 22 families was evaluated by assessing the number of brooms formed per tree during 10 years under field conditions. The population was established in randomized blocks with three replications of 12 plants each. Significant differences were observed among families. The most outstanding families were NA33 x RB39 and RB39 x P4B, which presented the lowest WB incidence during 10 years. The increase in natural field infection of Scavina clones families and their descendants were clearly demonstrated after 2006. The existence of additive effects for resistance appears clearly for families, which had other source of resistance associated with Scavina. Clones RB39, RB36, P4B, NA33 and CSUL3 are promising parents for pyramiding resistance genes and increasing the stability and durability of resistance to WB

Pyrolyzed chitosan-based materials for CO2/CH4 separation

Chitosan is a biopolymer obtained by deacetylation of chitin extracted from sub-products of the food industry and it is rich in nitrogen content. Pyrolyzed chitosan– and chitosan-periodic mesoporous organosilica (PMO)– based porous materials with different pore structures and chemical features are prepared using different dry methods and ensuing pyrolysis at 800 °C, for application in the CO2/CH4 adsorption/separation. The highest CO2 adsorption capacity (1.37 mol·kg−1 at 100 kPa; 1.9 mol·kg−1 at 500 kPa) and the best selectivity for CO2/CH4 separation (95 at 500 kPa) is obtained using 1.5% (m/v) of chitosan solution dried under supercritical CO2. This material combines a good CO2 adsorption capacity with one of the highest selectivities for CO2/CH4 separation of the literature, arising as a promising alternative adsorbent for natural gas or biogas upgrading at reduced cost. The presence of high nitrogen content together with pores of diameter around 2 nm leads to an increase of the CO2 adsorption capacity. In the case of chitosan-PMO-based materials, the activation step using both acid and crushing methods is crucial to increase the CO2 adsorbed amount. Here, the highest CO2 adsorption capacity and the highest selectivity are obtained by the chitosan-PMO crushed adsorbent and the chitosan-PMO material activated with sulfuric acid, respectively. These observations indicate the importance of the controlled attack of the material surface to enhance the diffusion of the target gases within the adsorbent, avoiding the adsorption of other species.publishe

The Effect of Light Wavelength on CO2 Capture, Biomass Production and Nutrient Uptake by Green Microalgae: A Step Forward on Process Integration and Optimisation

Microalgae have drawn the attention of several researchers as an alternative to the traditional physicochemical CO2 capture methods, since they can convert CO2 and water into organic matter and release oxygen into the atmosphere. Microalgal growth can be improved by changing light supply, such as light intensity, wavelength, and photoperiod. In this study, the effect of different light wavelengths on CO2 capture, nutrient removal from a synthetic effluent and biomass production of Chlorella vulgaris, Tetradesmus obliquus and Neochloris oleoabundans was studied. The experiments were conducted with light-emitting diodes (LEDs) with different wavelengths: 380-750 nm (white), 620-750 nm (red) and 450-495 nm (blue). The maximum specific growth rate was obtained by N. oleoabundans with white LEDs (0.264 +/- 0.005 d(-1)), whereas the maximum biomass productivity (14 +/- 4 mg(dw) L-1 d(-1)) and CO2 fixation rate (11.4 mg(CO2) L-1 d(-1)) were obtained by C. vulgaris (also with white LEDs). Nitrogen and phosphorus removal efficiencies obtained under white light conditions were also the highest for the three studied microalgae

Fully automated countrywide monitoring of fuel break maintenance operations

PTDC/CCI-COM/30344/2017 PCIF/SSI/0102/2017 UIDB/00239/2020 UIDB/00066/2020Fuel break (FB) networks are strategic locations for fire control and suppression. In order to be effective for wildfire control, they need to be maintained through regular interventions to reduce fuel loads. In this paper, we describe a monitoring system relying on Earth observations to detect fuel reduction inside the FB network being implemented in Portugal. Two fast automated pixel-based methodologies for monthly monitoring of fuel removals in FB are developed and compared. The first method (M1) is a classical supervised classification using the difference and postdisturbance image of monthly image composites. To take into account the impact of different land cover and phenology in the detection of fuel treatments, a second method (M2) based on an innovative statistical change detection approach was developed. M2 explores time series of vegetation indices and does not require training data or user-defined thresholds. The two algorithms were applied to Sentinel-2 10 m bands and fully processed in the cloud-based platform Google Earth Engine. Overall, the unsupervised M2, which is based on a Welch t-test of two moving window averages, gives better results than the supervised M1 and is suitable for an automated countrywide fuel treatment detection. For both methods, two vegetation indices, the Modified Excess of Green and the Normalized Difference Vegetation Index, were compared and exhibited similar performances.publishersversionpublishe

Bi-modified Pt Electrodes toward Glycerol Electrooxidation in Alkaline Solution: Effects on Activity and Selectivity

Herein we investigate the effect of irreversibly adsorbed bismuth on polycrystalline platinum (Ptp) on the electrooxidation of glycerol in alkaline media by combining electrochemical, spectroscopic (in situ FTIR), and analytical (HPLC on line) techniques. We found that the activity of Ptp increases by about 5-fold when the optimal quantity of Bi ions is added to the solution. Besides, the adatom strongly impacts the reaction products by suppressing the pathways with C–C bond breaking, hindering the formation of CO (and other unknown intermediates) and enhancing the production of glycerate. Different from the results in acid media for Ptp-Bi systems where Bi blocks the oxidation pathway through the primary carbon, glycerate is the main product in alkaline media, and dihydroxyacetone is either produced in extremely low quantities or not produced. Besides, comparing our results with those in acid media, the peak current recorded at 1 mV·s–1 in this work was 1 order of magnitude higher. These results show the strong impact of the pH in the reaction rate and selectivity.Financial support from the Brazilian agencies: PSF and JLB thanks FAPESP (grants: 2016/01365-0) and Shell and the strategic importance of the support given by ANP (Brazil’s National Oil, Natural Gas and Biofuels Agency) through the R&D levy regulation. MBCS thanks PRP-FAEPEX and RAV and VYY thanks SAE-Unicamp for their scholarships. J.S-G. acknowledges financial support from VITC (Vicerrectorado de Investigación y Transferencia de Conocimiento) of the University of Alicante (UATALENTO16-02)

Multicommuted flow system for the determination of glucose in animal blood serum exploiting enzymatic reaction and chemiluminescence detection

An automatic flow procedure based on multicommutation dedicated for the determination of glucose in animal blood serum using glucose oxidase with chemiluminescence detection is described. The flow manifold consisted of a set of three-way solenoid valves assembled to implement multicommutation. A microcomputer furnished with an electronic interface and software written in Quick BASIC 4.5 controlled the manifold and performed data acquisition. Glucose oxidase was immobilized on porous silica beads (glass aminopropyl) and packed in a minicolumn (15 × 5 mm). The procedure was based on the enzymatic degradation of glucose, producing hydrogen peroxide, which oxidized luminol in the presence of hexacyanoferrate(III), causing the chemiluminescence. The system was tested by analysing a set of serum animal samples without previous treatment. Results were in agreement with those obtained with the conventional method (LABTEST Kit) at the 95% confidence level. The detection limit and variation coefficient were estimated as 12.0 mg l(−1) (99.7% confidence level) and 3.5% (n = 20), respectively. The sampling rate was about 60 determinations h(−1) with sample concentrations ranging from 50 to 600 mg l(−1) glucose. The consumptions of serum sample, hexacyanoferrate(III) and luminol were 46 μl, 10.0 mg and 0.2 mg/determination, respectively

Bi2Te3 and Sb2Te3 Thin Films with Enhanced Thermoelectric Properties for Flexible Thermal Sensors

The influence of substrate type in boosting thermoelectric properties of co-evaporated Bi2Te3 and Sb2Te3 films (with 400 nm-thick) is here reported. Optimized power factor values are 2.7 × 10−3 W K−2 m−1 and 1.4 × 10−3 W K−2 m−1 for flexible Bi2Te3 and Sb2Te3 films, respectively. This is an important result as it is at least 2 times higher than the power factor found in the literature for flexible Bi2Te3 and Sb2Te3 films. A flexible infrared thermopile sensor was developed with high detectivity (2.50 × 107 cm √HzW−1).This work is supported by FCT with the reference project UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020—Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI-01-0145-FEDER-006941. EMFV and JF is grateful for financial support through the FCT grants SFRH/BPD/95905/2013 and SFRH/BD/121679/2016

Seroprevalence and Risk Factors Associated with Leishmania Infection in Dogs from Portugal

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