Development of methods for the determination of phytohormones in plant samples by HPLC-DAD/FD

Plant hormones are a group of naturally occurring, organic substances which influence physiological processes at low concentrations. The processes influenced consist mainly of growth, differentiation and development, though other processes, such as stomatal movement, may also be affected. In this work phytohormones determination was performed by HPLC-DAD/FD. The method was applied to several plant samples, previously treated with a new polymeric phase synthetized in our lab

Synthesis, thermal, and mechanical characterisation of metakaolin-based geopolymers coloured with grape marc extract

Over the years, several materials have been used for restoration purposes, with different types of dyes and colour hues. Recently, some researchers have proposed geopolymers (GPs) or amorphous aluminosilicate polymers for these purposes. In this work, an alcohol-based grape marc extract (GME, obtained via dark maceration assisted with ultrasound) was used as a natural dyeing agent for metakaolin-based GPs. The geopolymerisation occurrence was assessed by Fourier-transform infrared (FT-IR) spectroscopy and X-ray diffraction analysis, while the colour of the resulting material was determined through the colorimetric analysis in the L*a*b* colour space. Additionally, the thermal stability of GME and GPs was investigated by thermogravimetry coupled with FT-IR spectroscopy. The microstructure, the reticulation stability, and the antimicrobial activity of GPs were examined through the scanning electron microscopy, the pH and ionic conductivity measurements, integrity, and mass loss tests. Overall, a coloured geopolymer with suitable thermal, antimicrobial, and mechanical properties was obtained, justifying its potential use in restoration or, more generally, in the construction field

Guidelines for a correct evaluation of deep eutectic solvents thermal stability

Deep eutectic solvents (DESs) are a class of versatile and green emerging materials. Despite the huge amounts of applications proposed in the last years, studies on their thermal stability are often missing. In this short review, we propose a guide for a correct evaluation of DES thermal stability, conducted mainly by dynamical thermogravimetry (TGA). We collected all the data reported in the literature on choline chloride (ChCl)-based DESs, as proof of concept to show the potentialities of the technique, highlighting all the parameters that need to be considered for a correct analysis, with particular attention to the possible sources of misleading interpretations (e.g. the adsorbed water, or the formation of undesired products during DES preparation). In many cases, the additional use of isothermal TGA, or TGA coupled with online techniques such as Fourier Infra-Red Spectroscopy or Mass Spectrometry, may help for the data interpretation. Besides, we summarize in a graph the degradation temperatures of many DESs and their precursors, intended as an operative guide to choosing the correct DES for different applications. The findings reported to date, highlight the potentialities of thermal analysis on DESs, as a powerful tool to obtain essential information on their applicability, and to implement the knowledge of their nanostructure from a molecular point of view

20 years of microwave technology developments using a coaxial antenna: From human health to green chemistry applications

The global interest on microwave assisted chemistry (MAC) is due to the important benefits for the sustainable growth of green chemical industries and environmentally friendly progress of society. MAC has been firstly developed using oven-type microwaves (MWs) assisted reactors, which requires difficult and expensive industrial scale-up. In 2002, the development of coaxial dipole antenna allowed a direct application of MWs in situ in the reaction media, opening a crucial, novel versatile technological solution, making MW-assisted processes feasible in any configuration at any industrial level. Here, we present an overview of the technological development of 20 years research using a coaxial MW antenna for green chemistry and human health applications. The major MW technology breakthroughs described in these short-review are: i) MW-induced thermoablation machine, ii) in situ MW heating in open glassware chemical reactors, iii) electrodeless MW/ultraviolet (UV) lamps and photoreactors, iv) MW-high pressure reactor and v) solventless/simultaneous MW/UV/ultrasound (US) configurations. Applications for the synthesis of nanocatalysts, nanoparticles and polymers, advanced oxidative decomposition photochemical processes, solvothermal extraction of valuable products and biomass processing are discussed. Remarks on the scaling up of the extraction processes and frontier applications addressed to the treatment of current and future outbreak pandemic emergences are also shown

Thermal and morphological investigations of alkali activated materials based on Sicilian volcanic precursors (Italy)

Insights on thermal behavior and microstructures of AAMs based on Sicilian volcanic precursors (i.e., volcanic ash, "ghiara" and pumice) have been performed. A multidisciplinary approach by means of thermogravimetric analysis coupled to Fourier Transform Infrared Spectroscopy and X-ray Computed Microtomography has been used with the aim to define the influence of reactants involved in the process. The obtained results show: i) the increase of metakaolin shifts the gas emission toward lower temperatures; ii) the positive relation between mass loss and liquid/solid ratio; iii) the influence of particle size of precursors on the pore development

Valorization of biomass wastes through eco-friendly extraction of valuable compounds suitable to produce innovative materials

La rapida urbanizzazione e l'intensificazione delle attività antropiche hanno portato a un'enorme produzione di rifiuti da biomassa. I metodi di smaltimento utilizzati (ad esempio, interramento in discarica e incenerimento) si sono rivelati inadeguati e hanno contribuito ad aumentare l'inquinamento ambientale. I rifiuti di biomassa derivati da scarti agricoli e alimentari e da residui animali sono una fonte a basso costo di importanti biopolimeri. Infatti, i principali composti che si possono ottenere da questi rifiuti sono polisaccaridi come cellulosa, emicellulosa, chitosano e pectina, proteine come collagene, gelatina e cheratina e lipidi come la cutina. Questi biopolimeri possono essere utilizzati per produrre biocarburanti, biomateriali e bioplastiche che possono sostituire i materiali derivati dai combustibili fossili. In questo contesto, il mio progetto di dottorato si è concentrato sul recupero della cheratina dalle piume di pollame, la biomassa di scarto a base di cheratina più abbondante. Sono stati studiati anche i rifiuti di bucce di agrumi, un'altra biomassa abbondante, dai quali è stata recuperata la pectina, un polisaccaride comunemente usato nell'industria alimentare con proprietà promettenti che lo rendono adatto anche ad applicazioni biomediche. Utilizzando la cheratina e la pectina estratte da queste biomasse di scarto sono stati prodotti nuovi biomateriali con applicazioni sia in ambito biomedicale che di bonifica ambientale. English version: Rapid urbanisation and the intensification of human activities have led to a huge production of biomass waste. The disposal methods used (e.g. landfilling and incineration) have proven to be inadequate and have contributed to increased environmental pollution. Biomass waste, derived from agricultural and food waste and animal residues, is an inexpensive source of important biopolymers. Indeed, the main compounds that can be obtained from these wastes are polysaccharides such as cellulose, hemicellulose, chitosan and pectin, proteins such as collagen, gelatin and keratin, and lipids such as cutin. These biopolymers can be used to produce biofuels, biomaterials and bioplastics that can replace materials derived from fossil fuels. In this context, my PhD project focused on the recovery of keratin from poultry feathers, the most abundant keratin-based waste biomass. Citrus peel waste, another abundant biomass, was also studied to recover pectin, a polysaccharide commonly used in the food industry with promising properties that also make it suitable for biomedical applications. Keratin and pectin extracted from these waste biomasses have been used to produce new biomaterials with applications in both biomedical and environmental remediation

Charting the CO2 capture performance of a phase-change metal-organic framework in a pressure-vacuum swing adsorption process

Metal-organic frameworks (MOFs) that display step-shaped adsorption isotherms, i.e., phase-change MOFs, represent a relatively small subset of all known MOFs. Yet, they are rapidly emerging as promising sorbents to achieve excellent gas separation performances with little energy demand. In this work, we assessed F4_MIL-140A(Ce), a recently discovered phase-change MOF adsorbent for CO2 capture in two scenarios using a pressure-vacuum swing adsorption process, namely a coal-fired power plant flue gas (12.5 %mol CO2), and a steel plant flue gas (25.5 %mol CO2). Four CO2 and three N2 adsorption isotherms were collected on F4_MIL-140A(Ce) over a range of temperatures and modelled using a bespoke equation for step-shaped isotherms. We accurately measured the heat capacity of F4_MIL-140A(Ce), a key thermodynamic property for a sorbent, using a method based on differential scanning calorimetry that overcomes the issues associated with the poor thermal conductivity of MOF powders. We then used these experimental data as input in a process optimisation framework and we compared the CO2 capture performance of F4_MIL-140A(Ce) to that of other “canonical” sorbents, including, zeolite 13X, activated carbon and three MOFs (i.e., HKUST-1, UTSA-16 and CALF-20). We found that F4_MIL-140A(Ce) outranks other sorbents, in terms of recovery and purity, in most of the simulated process conditions. We attribute such promising performance to the non-hysteretic step-shaped isotherm, the low uptake capacity for N2 and the mild heat of CO2 adsorption displayed by F4_MIL-140A(Ce)

Thermochemical Evaluation of Different Waste Biomasses (Citrus Peels, Aromatic Herbs, and Poultry Feathers) towards Their Use for Energy Production

The biomass waste obtained at the end-of-pipe of the extraction industry can be used as fuel for energy production, aiming at cost reduction/waste disposal issues. However, few systematic investigations into the calorific value of these residues are reported in the literature. In this work, the thermochemical properties of solid residues from different biomasses (residues from citrus peels, leaves, flowers, stems, and poultry feathers used for extraction) as potential biomass fuels have been investigated. The heat of combustion (ΔcH) of the solid residues from citrus (orange, tangerine, lemon, grapefruit, and pomelo), aromatic herbs (rosemary, lavender, thyme, Artemisia vulgaris L. and Ruta chalepensis L.), and poultry feathers biomasses was measured by direct calorimetry. The results were compared with the higher heating values (HHV) calculated using the elemental (CHNOS) and thermogravimetric (TGA) analyses data and with the enthalpy of combustion calculated using the biomass composition predicted by FTIR spectroscopy in tandem with chemometrics. The calculated values match with the corresponding experimental values of ΔcH. The heat of combustion highlights the energetic features of solid residues for their potential uses as alternative biomass for energy production. This information is essential to evaluate the employment of solid residues as fossil fuel substitutes