The valorization of industrial byproducts is an emerging practice that aims to transform waste materials generated during production processes into valuable resources. In this work, a preliminary study was carried out on the thermal conversion of an industrial solid byproduct resulting from the pickling of metal surfaces, mainly containing iron (II) oxalate. In a fixed-bed reactor, the thermal conversion was investigated as a function of the operating temperature and overall time.
View Article and Find Full Text PDFThe production of cementitious formulations involves the addition of chemical additives essential for the optimization of many properties. Superplasticizers are considered additives of great interest but when mixed with concrete they lead to an undesirable increase of air content, with the consequent development of foam. This can adversely affect both mechanical properties and workability, therefore, the use of an antifoam agent is also necessary which should be able to prevent or destroy the foam.
View Article and Find Full Text PDFAmidation of lactobionic acid with N,N-dimethylaminopropyltriamine was conducted to obtain N-(3'-dimethylaminopropyl)-lactamido-3-aminopropane (DDLPD), which was quaternized with bromoalkanes of different carbon chain lengths to synthesize double-stranded lactosylamide quaternary ammonium salt N-[N'[3-(lactosylamide)]propyl-N'-alkyl] propyl-N,N-dimethyl-N-alkylammonium bromide (CDDLPB, n = 8, 10, 12, 14, 16). The surface activity and the adsorption and aggregation behaviors of the surfactants were investigated via equilibrium surface tension, dynamic light scattering, and cryo-electron microscopy measurements in an aqueous solution. The application properties of the products in terms of wettability, emulsification, foam properties, antistatic, salt resistance, and bacteriostatic properties were tested.
View Article and Find Full Text PDFEvery year, new compounds contained in consumer products, such as detergents, paints, products for personal hygiene, and drugs for human and veterinary use, are identified in wastewater and are added to the list of molecules that need monitoring. These compounds are indicated with the term emerging contaminants (or Contaminants of Emerging Concern, CECs) since they are potentially dangerous for the environment and human health. To date, among the most widely used methodologies for the removal of CECs from the aquatic environment, adsorption processes play a role of primary importance, as they have proven to be characterized by high removal efficiency, low operating and management costs, and an absence of undesirable by-products.
View Article and Find Full Text PDFThe abatement of iopamidol (IPM), an X-ray iodinated contrast agent, in aqueous solution using powdered activated carbon (PAC) as a sorbent was investigated in the present work. The material was characterized by various analytical techniques such as thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, Brunauer-Emmett-Teller analysis, dynamic light scattering, and zeta potential measurements. Both thermodynamic and kinetic experiments were conducted in a batch apparatus, and the effects of the initial concentration of IPM, the temperature, and the adsorbent bulk density on the adsorption kinetics were investigated.
View Article and Find Full Text PDFPelargonic acid (PA) is commercially obtained by oxidative cleavage of fatty acid double bonds. Its esters are interesting compounds used to create bio-based products. An industrially relevant application of these compounds is in the field of solvent manufacturing and formulation of green lubricating oils.
View Article and Find Full Text PDFThe adsorption efficiency of commercial activated carbon toward ibuprofen (IBU) was investigated and described using the adsorption dynamic intraparticle model (ADIM). Although the adsorption capacity of activated carbon has been widely studied, the kinetic models used in the literature are simplified, treating adsorption kinetics with pseudo-kinetic approaches. In this paper, a realistic model is proposed, quantitatively describing the influence of the main operation parameters on the adsorption kinetics and thermodynamics.
View Article and Find Full Text PDFThe study reports the enzymatic synthesis of bio-based oligoesters and chemo-enzymatic processes for obtaining epoxidized bioplasticizers and biolubricants starting from cardoon seed oil. All of the molecules had M below 1000 g mol and were analyzed in terms of marine biodegradation. The data shed light on the effects of the chemical structure, chemical bond lability, thermal behavior, and water solubility on biodegradation.
View Article and Find Full Text PDFThe catalytic properties of a simple iron-containing MOF based on fumaric acid, MIL-88A, were investigated in the ketalization of ethyl levulinate with glycerol. The corresponding product is a component of current interest as a renewable building block for many uses. Under the following conditions (solventless, 120 °C, stoichiometric ratio, 1% cat.
View Article and Find Full Text PDFCardoon, Cynara cardunculus L. represents a biorefinery crop with a great potential in the bioplastic field. This work investigates the valorization of different cardoon components into high added value products, finally recombined into novel upgraded bioplastics.
View Article and Find Full Text PDFIn this work, the effective adsorption and the subsequent photodegradation activity, of TiO brookite nanoparticles, for the removal of anionic dyes, namely, Alizarin Red S (ARS) and Bromocresol Green (BCG) were studied. Batch adsorption experiments were conducted to investigate the effect of both dyes' concentration, contact time, and temperature. Photodegradation experiments for the adsorbed dyes were achieved using ultraviolet light illumination (6 W, λ = 365 nm).
View Article and Find Full Text PDFVarious catalysts were used to catalyze the ethoxylation reaction of C12-14 primary alcohols with ethylene oxide. Alcohol ethoxylates with a ratio of ethylene oxide/substrate near 3 were synthesized. The catalysts influenced the reaction rate, molecular weight distribution of adducts, and formation of byproducts.
View Article and Find Full Text PDFThis work describes the use of simple zinc(II) salts (ZnCl, ZnCO, Zn(OAc), ZnO, Zn(ClO), Zn(TfO), and Zn(BF)) as effective catalysts for the esterification of fatty acids with long-chain alcohols and simple polyols through a homogeneous system that allows the gradual and selective removal of water. The results show that the catalytic activity depends on the nature of the counterion: the most effective are the salts with poorly coordinating anions (perchlorate and triflate) or containing basic Brønsted anions (oxide, acetate, and carbonate). However, only with the latter is it possible to fully recover the catalyst at the end of each run, which is easily filtered in the form of zinc carboxylate, given its insolubility in the ester produced.
View Article and Find Full Text PDFFront Bioeng Biotechnol
January 2021
The transition toward "green" alternatives to petroleum-based plastics is driven by the need for "drop-in" replacement materials able to combine characteristics of existing plastics with biodegradability and renewability features. Promising alternatives are the polyhydroxyalkanoates (PHAs), microbial biodegradable polyesters produced by a wide range of microorganisms as carbon, energy, and redox storage material, displaying properties very close to fossil-fuel-derived polyolefins. Among PHAs, polyhydroxybutyrate (PHB) is by far the most well-studied polymer.
View Article and Find Full Text PDFChemical compounds within tea are characterized by an extensive heterogeneity; some of them are crucial for their protective and defensive role in plants, and are closely connected to the benefits that the consumption of tea can provide. This paper is mainly focused on the characterization of polyphenols (secondary metabolites generally involved in defense against ultraviolet radiation and aggression by pathogens) and metals, extracted from nine Chinese tea samples, by integrating different mass spectrometry methodologies, LC-MS/MS in multiple reaction monitoring (MRM) and inductively coupled plasma mass spectrometry (ICP-MS). Our approach allowed to identify and compare forty polyphenols differently distributed in tea infusions at various fermentation levels.
View Article and Find Full Text PDFDiffusion plays a central part in many unit operations. The Maxwell-Stefan model is the dominant model for both gaseous and liquid diffusion. However, it was developed from the kinetic theory of gases, raising the question of whether it can be extended to non-ideal liquid systems.
View Article and Find Full Text PDFTaylor dispersion method is a common technique for the determination of diffusion coefficients in the case of multicomponent systems. One of the main problems related to the parameter estimation analysis of the collected results is the choice of the best minimization algorithm that allows finding the real minimum of the objective function. Usually, researchers use the Levenberg-Marquardt algorithm, averaging the parameters obtained by different estimation analyses.
View Article and Find Full Text PDFThe present work deals with the production of monoalkyl glyceryl ethers (MAGEs) through a new reaction pathway based on the reaction of glycidol and alcohols catalyzed by Lewis acid-based catalysts. Glycidol is quantitatively converted with high selectivity (99 %) into MAGEs under very mild reaction conditions (80 °C and 0.01 mol % catalyst loading) in only 1 h using Al(OTf) or Bi(OTf) as catalyst.
View Article and Find Full Text PDFThe simple transfer of established chemical production processes from batch to flow chemistry does not automatically result in more sustainable ones. Detailed process understanding and the motivation to scrutinize known process conditions are necessary factors for success. Although the focus is usually "only" on intensifying transport phenomena to operate under intrinsic kinetics, there is also a large intensification potential in chemistry under harsh conditions and in the specific design of flow processes.
View Article and Find Full Text PDFThe silver-assisted ligand metathesis reaction involving a platinum(II) complex of formula [PtClMe(N,N-chelate)] with acetonitrile has been investigated. By using a suitably hindered N,N-chelate, an otherwise hardly detectable trinuclear species has been isolated and characterized through X-ray diffractometry. The trinuclear cation consists of two nearly orthogonal [PtCl(Me)(N,N-chelate)] square-planar units entrapping an Ag(+) cation through the chloride ligands that, acting as bidentate, form a linear AgCl(2) unit with two nonequivalent Ag-Cl bonds.
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