Carbon dioxide (CO2) impacts the greenhouse effect significantly and results in global warming, prompting urgent attention to climate change concerns. In response, CO2 capture has emerged as a ...crucial process to capture carbon produced in industrial and power processes before its release into the atmosphere. The main aim of CO2 capture is to mitigate the emissions of greenhouse gas and reduce the anthropogenic impact on climate change. Biopolymer nanocomposites offer a promising avenue for CO2 capture due to their renewable nature. These composites consist of biopolymers derived from biological sources and nanofillers like nanoparticles and nanotubes, enhancing the properties of the composite. Various biopolymers like chitosan, cellulose, carrageenan, and others, possessing unique functional groups, can interact with CO2 molecules. Nanofillers are incorporated to improve mechanical, thermal, and sorption properties, with materials such as graphene, carbon nanotubes, and metallic nanoparticles enhancing surface area and porosity. The CO2 capture mechanism within biopolymer nanocomposites involves physical absorption, chemisorption, and physisorption, driven by functional groups like amino and hydroxyl groups in the biopolymer matrix. The integration of nanofillers further boosts CO2 adsorption capacity by increasing surface area and porosity. Numerous advanced materials, including biopolymeric derivatives like cellulose, alginate, and chitosan, are developed for CO2 capture technology, offering accessibility and cost-effectiveness. This semi-systematic literature review focuses on recent studies involving biopolymer-based materials for CO2 capture, providing an overview of composite materials enriched with nanomaterials, specifically based on cellulose, alginate, chitosan, and carrageenan; the choice of these biopolymers is dictated by the lack of a literature perspective focused on a currently relevant topic such as these biorenewable resources in the framework of carbon capture. The production and efficacy of biopolymer-based adsorbents and membranes are examined, shedding light on potential trends in global CO2 capture technology enhancement.
Deferiprone, generally, is considered an important chelating agent for Fe3+ overload. From a literature data analysis, a lack of information on the interaction of this molecule toward a series of ...metal cations emerged, inducing to fill out the topic. The complexing ability of deferiprone toward Ca2+, Mg2+, Cd2+ and Pb2+ was studied by potentiometry and 1H NMR spectroscopy, in KCl aqueous solutions at different ionic strength values (0.1 ≤ I/mol dm−3 ≤ 1.0) and T = 298.15 K. The same speciation model featured by the ML, ML2, ML3 and ML(OH) (M = metal and L = deferiprone or DFP) species was obtained for Cd2+ and Pb2+; the formation constants calculated at infinite dilution are: logTβ = 7.23±0.02, 12.47±0.03, 16.70±0.04, and −2.53±0.04, respectively for Cd2+ and 9.91±0.01, 15.99±0.02, 19.93±0.05 and 0.99±0.02 for Pb2+. Only two species, namely ML and ML2, were determined for Ca2+ and Mg2+, whose formation constants at infinite dilution are respectively: 3.72±0.01 and 6.50±0.02, for the first one, 5.31±0.01 and 9.58±0.01, for the second. The ligand sequestering ability and affinity toward M2+ were evaluated by determining the pL0.5 and pM parameters at different pHs and ionic strengths. The results suggest that deferiprone has the best complexing and sequestering ability toward Pb2+, followed by Cd2+, Mg2+ and Ca2+, respectively. 1H NMR studies confirmed the DFP affinity for Cd2+ and Pb2+, and in combination with DFT calculations showed that metal cations are bound to the hydroxo-oxo moiety of the pyridinone ring. The data reported in this study provide information on the possible employment of a small molecule like deferiprone, as a chelating and sequestering agent for Pb2+ accumulation or overload from environmental and biological matrices.
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•Speciation study on the deferiprone interactions toward Ca2+, Mg2+, Cd2+, Pb2+.•Potential use of deferiprone ligand to remove Pb2+ contamination.•Future applications on real environmental matrixes.
The binding ability of five bifunctional 3-hydroxy-4-pyridinones towards Cu
and Fe
was studied by means of potentiometric and UV-Vis spectrophotometric measurements carried out at
= 0.15 mol L
in ...NaCl
= 298.15 K and 310.15 K. The data treatments allowed us to determine speciation schemes featured by metal-ligand species with different stoichiometry and stability, owing to the various functional groups present in the 3-hydroxy-4-pyridinones structures, which could potentially participate in the metal complexation, and in the Cu
and Fe
behaviour in aqueous solution. Furthermore, the sequestering ability and metal chelating affinity of the ligands were investigated by the determination of p
and pM parameters at different pH conditions. Finally, a comparison between the Cu
and Fe
/3-hydroxy-4-pyridinones data herein presented with those already reported in the literature on the interaction of Zn
and Al
with the same ligands showed that, from the thermodynamic point of view, the 3-hydroxy-4-pyridinones are particularly selective towards Fe
and could therefore be considered promising iron-chelating agents, also avoiding the possibility of competition, and eventually the depletion, of essential metal cations of biological and environmental relevance, such as Cu
and Zn
.
The interactions of dopamine 2-(3,4-Dihydroxyphenyl)ethylamine, (Dop−) with cadmium(II), copper(II) and uranyl(VI) were studied in NaCl(aq) at different ionic strengths (0 ≤ I/mol dm−3 ≤ 1.0) and ...temperatures (288.15 ≤ T/K ≤ 318.15). From the elaboration of the experimental data, it was found that the speciation models are featured by species of different stoichiometry and stability. In particular for cadmium, the formation of only MLH, ML and ML2 (M = Cd2+; L = dopamine) species was obtained. For uranyl(VI) (UO22+), the speciation scheme is influenced by the use of UO2(acetate)2 salt as a chemical; in this case, the formation of ML2, MLOH and the ternary MLAc (Ac = acetate) species in a wide pH range was observed. The most complex speciation model was obtained for the interaction of Cu2+ with dopamine; in this case we observed the formation of the following species: ML2, M2L, M2L2, M2L2(OH)2, M2LOH and ML2OH. These speciation models were determined at each ionic strength and temperature investigated. As a further contribution to this kind of investigation, the ternary interactions of dopamine with UO22+/Cd2+ and UO22+/Cu2+ were investigated at I = 0.15 mol dm−3 and T = 298.15K. These systems have different speciation models, with the MM’L and M2M’L2OH M = UO22+; M’ = Cd2+ or Cu2+, L = dopamine common species; the species of the mixed Cd2+ containing system have a higher stability with respect the Cu2+ containing one. The dependence on the ionic strength of complex formation constants was modelled by using both an extended Debye–Hückel equation that included the Van’t Hoff term for the calculation of the formation enthalpy change values and the Specific Ion Interaction Theory (SIT). The results highlighted that, in general, the entropy is the driving force of the process. The quantification of the effective sequestering ability of dopamine towards the studied cations was evaluated by using a Boltzmann-type equation and the calculation of pL0.5 parameter. The sequestering ability was quantified at different ionic strengths, temperatures and pHs, and this resulted, in general, that the pL0.5 trend was always: UO22+ > Cu2+ > Cd2+.
The speciation of epinephrine (
) in the presence of alginate (
) and two biological and environmental relevant metal cations (Cu
, UO
) was investigated at
= 298.15K,
= 0.15-1.00 mol dm
in NaCl
. ...The formation of binary and ternary complexes was evaluated and, since epinephrine can behave as a zwitterion, the
/
interaction was studied by means of DOSY NMR. The dependence of the equilibrium constants on ionic strength was studied using an extended Debye-Hückel type equation and the SIT approach. The effect of temperature was investigated by means of isoperibolic titration calorimetry: the entropic contribution was the driving force for the Cu
/
complexes formation. The sequestering ability of
and
on Cu
, evaluated by the pL
calculation, increased with pH and ionic strength. The determination of pM parameter showed that
had a higher Cu
affinity with respect to
. The formation of
/
species was also investigated by UV-Vis spectrophotometry and
H NMR measurements. The ternary Cu
/
/
and Cu
/UO
/
interactions were also studied. The "extra-stability" calculated for the mixed ternary species confirmed that their formation was thermodynamically favorable.
The acid–base properties of two bifunctional 3-hydroxy-4-pyridinone ligands and their chelating capacity towards Zn2+, an essential bio-metal cation, were investigated in NaCl aqueous solutions by ...potentiometric, UV-Vis spectrophotometric, and 1H NMR spectroscopic titrations, carried out at 0.15 ≤ I/mol −1 ≤ 1.00 and 288.15 ≤ T/K ≤ 310.15. A study at I = 0.15 mol L−1 and T = 298.15 K was also performed for other three Zn2+/Lz− systems, with ligands belonging to the same family of compounds. The processing of experimental data allowed the determination of protonation and stability constants, which showed accordance with the data obtained from the different analytical techniques used, and with those reported in the literature for the same class of compounds. ESI-MS spectrometric measurements provided support for the formation of the different Zn2+/ligand species, while computational molecular simulations allowed information to be gained on the metal–ligand coordination. The dependence on ionic strength and the temperature of equilibrium constants were investigated by means of the extended Debye–Hückel model, the classical specific ion interaction theory, and the van’t Hoff equations, respectively.
The exploitation of macroalgal biomass, as a source of antibacterial drugs, would result into the valuable transformation of waste into an economic resource. Ethanol and water extracts or ...polysaccharides, from nine DNA-barcoded macroalgae (2 Chlorophyta, 5 Ochrophyta and 2 Rhodophyta) collected from Italian coastal environments, were screened for antibacterial activity against ten bacterial pathogens with relevance for aquaculture and human health. All extracts have not cytotoxic effects on molluscan digestive gland cells and mammalian red blood cells. As resulted by agar diffusion assays, water extracts showed broader and higher inhibitory activity than ethanol extracts against the tested pathogens. Polysaccharides from Fucus virsoides (Ochrophyta) possessed the strongest inhibitory activity against Aeromonas salmonicida subsp. salmonicida and Photobacterium damselae subsp. damselae, an emergent pathogen for humans. Polysaccharides from Undaria pinnatifida (Ochrophyta) were the most active against V. harveyi, the major pathogen responsible for diseases in aquaculture, and also against a multiresistant, clinical strain of Pseudomonas aeruginosa. Our results suggest that these polysaccharides could represent a novel source of compounds active against bacterial pathogens relevant for eco-sustainable aquaculture and human health.
The interactions of dopamine 2-(3,4-Dihydroxyphenyl)ethylamine, (Dop
) with methylmercury(II) (CH
Hg
), magnesium(II), calcium(II), and tin(II) were studied in NaCl(aq) at different ionic strengths ...and temperatures. Different speciation models were obtained, mainly characterized by mononuclear species. Only for Sn
we observed the formation of binuclear complexes (M
L
and M
LOH (charge omitted for simplicity); M = Sn
, L = Dop
). For CH
Hg
, the speciation model reported the ternary MLCl (M = CH
Hg
) complex. The dependence on the ionic strength of complex formation constants was modeled by using both an extended Debye-Hückel equation that included the Van't Hoff term for the calculation of enthalpy change values of the formation and the Specific Ion Interaction Theory (SIT). The results highlighted that, in general, the entropy is the driving force of the process. The sequestering ability of dopamine towards the investigated cations was evaluated using the calculation of pL
parameter. The sequestering ability trend resulted to be: Sn
> CH
Hg
> Ca
> Mg
. For example, at
= 0.15 mol dm
,
= 298.15 K and pH = 7.4, pL
= 3.46, 2.63, 1.15, and 2.27 for Sn
, CH
Hg
, Ca
and Mg
(pH = 9.5 for Mg
), respectively. For the Ca
/Dop
system, the precipitates collected at the end of the potentiometric titrations were analyzed by thermogravimetry (TGA). The thermogravimetric calculations highlighted the formation of solid with stoichiometry dependent on the different metal:ligand ratios and concentrations of the starting solutions.
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