RESUMO
The policy makers gathered at COP27 set a goal of limiting global warming to 1.5 °C above the pre- industrial level which requires a reduction of CO2 emissions of 43% by 2030 (relative to 2019 value). To meet this target, it is imperative to replace fossil derivatives (fuels and chemicals) with biomass derivatives. Given that 70% of planet Earth is the ocean, blue carbon can contribute significantly to the mitigation of anthropogenic carbon emissions. Marine macroalgal, or seaweed, that stores carbon, mostly, in the form of sugars rather than lignocellulosic, like terrestrial biomass, is suitable as input raw material for biorefineries. Seaweed biomass has high growth rates, does not require fresh water or arable land, and therefore does not compete with conventional food production. To make seaweed based biorefineries profitable the valorization of biomass has to be maximized through cascade processes with the production of several high-value products such as pharmaceuticals/chemicals, nutraceuticals, cosmetics, food, feed, fertilizers/biostimulants and low-carbon fuels. The composition of macroalgae, which varies depending on the species (green, red, or brown), the region in which it is grown, and the time of year, determines the variety of goods that can be made from it. Fuels must be made from seaweed leftovers since the market value of pharmaceuticals and chemicals is substantially larger than that of fuels. The following sections present a literature review on seaweed biomass valorization in the context of biorefinery with particular emphasis on low-carbon fuel production processes. An overview of seaweed's geographical distribution, composition, and production processes is also presented.
Assuntos
Alga Marinha , Alga Marinha/química , Biocombustíveis , Biomassa , Verduras , Preparações FarmacêuticasRESUMO
We report a straightforward and reproducible electrochemical approach to develop polydopamine-ethanolamine (ePDA-ETA) films to be used as immunosensing interfaces. ETA is strongly attached to polydopamine films during the potentiodynamic electropolymerization of dopamine. The great advantage of the electrochemical methods is to generate the oxidized species (quinones), which can readily react with ETA amine groups present in solution, with the subsequent incorporation of this molecule in the polymer. The presence of ETA and its effect on the electrosynthesis of polydopamine was accessed by cyclic voltammetry, ellipsometry, atomic force microscopy, FTIR and X-ray photoelectron spectroscopy. The adhesive and biocompatible films enable a facile protein linkage, are resilient to flow assays, and display intrinsic anti-fouling properties to block non-specific protein interactions, as monitored by real-time surface plasmon resonance, and confirmed by ellipsometry. Immunoglobulin G (IgG) and Anti-IgG were used in this work as model proteins for the affinity sensor. By using the one-step methodology (ePDA-ETA), the lower amount of immobilized biorecognition element, IgG, compared to that deposited on ePDA or on ETA post-modified film (ePDA/ETA), allied to the presence of ETA, improved the antibody-antigen affinity interaction. The great potential of the developed platform is its versatility to be used with any target biorecognition molecules, allowing both optical and electrochemical detection.
RESUMO
In recent years particular effort is being devoted towards the development of radiofrequency (rf) pulsed glow discharges (GDs) coupled to optical emission spectrometry (OES) for depth profile analysis of materials with technological interest. In this work, pulsed rf-GD-OES is investigated for the fast and sensitive depth characterization of Zn-TiO(2) nanocomposite films deposited on conductive substrates (Ti and steel). The first part of this work focuses on assessing the advantages of pulsed GDs, in comparison with the continuous GD, in terms of analytical emission intensities and emission yields. Next, the capability of pulsed rf-GD-OES for determination of thickness and compositional depth profiles is demonstrated by resorting to a simple multi-matrix calibration procedure. A rf forward power of 75 W, a pressure of 600 Pa, 10 kHz pulse frequency and 50% duty cycle were selected as GD operation parameters.Quantitative depth profiles obtained with the GD proposed methodology for Zn-TiO(2) nanocomposite films, prepared by the occlusion electrodeposition method using pulsed reverse current electrolysis, have proved to be in good agreement with results achieved by complementary techniques, including scanning electron microscopy and inductively coupled plasma-mass spectrometry. The work carried out demonstrates that pulsed rf-GD-OES is a promising tool for the fast analytical characterization of nanocomposite films.
