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A comprehensive investigation has been conducted on Ba(2-x)Sr(x)GdFeNb4O15 powders. These powders were synthesized through the conventional solid-state reaction. X-ray diffraction analysis at room temperature has demonstrated that the samples adopt the TTB-structure, exhibiting the space-group P4/mbm. The Raman spectra of the samples exhibit remarkable similarity, yet distinct bands at different wave numbers, indicative of the varying modes of the MO6 octahedra. The dielectric studies have uncovered intriguing findings, including a high dielectric constant and a broad permittivity peak. Remarkably, the Curie temperature varies with the substitution rate, yet remains frequency-independent, a clear indication of these materials' classical ferroelectric behavior. [ABSTRACT FROM AUTHOR]

The substance Ag3SbS3 could be a viable option guaranteeing extraordinary performance for electrodes with high storage capacity, but also for solar cell absorbents. For optimal manufacturing, Ag3SbS3 thin films were electrodeposited on Fluorine-Tin Oxide (FTO) and then sulfurized at different temperatures. Structurally, XRD and RAMAN analyses confirmed that hexagonal polycrystallization of the Ag3SbS3 phase is only effective for sulfurization at 475 °C. After elaboration, the thin films were analyzed morphologically, optically and electrochemically to better define their physicochemical performances. Cyclic voltammetry (CV) analysis proved that the co-electrodeposited Ag3SbS3/FTO electrode has a pseudo-capacitor behavior in Li2CO3 (0.5 M) under the [− 700, 0 mV] potential window, developing a specific capacitance of more than 810 F/g. Furthermore, the galvanostatic charge–discharge (GCD) confirms this pseudo-capacitor behavior and that by varying the current from 1 to 5 mA, the specific energy decreases slightly from 14.5 to 11.1 Wh kg−1 to the inverse of the specific power, which varies from 175.1 to 875.3 W. k g−1. Finally, the DFT calculation executed within the framework of generalized gradient approximation (GGA) with a modified Becke-Johnson exchange–correlation potential (mBJ) predicts results extremely comparable to those discovered experimentally and which are precisely an optical gap and an absorption coefficient of the order of 105 cm−1 and 1.62 eV, respectively. All of this enabled us to conclude that Ag3SbS3 possesses the physicochemical characteristics to make it an attractive option in the disciplines of supercapacity as well as photovoltaic. [ABSTRACT FROM AUTHOR]

The optimization of the factors influencing the co-electrodeposition method makes it extremely efficient in the production of thin films formed by multiple elements. This work presents the synthesis of Cu2CoSnS4 (CCTS) thin films by the simultaneous electrodeposition of Co, Sn, Cu, and S elements on the FTO substrate using tartaric acid (HT) as a complexing agent. To study the influence of copper concentration on the physicochemical properties of CCTS, these films were deposited at a co-electrodeposition potential of − 900 mV for concentrations [Cu2+] ranging from 0.015 to 0.030 M (vs. saturated calomel electrode (SCE)). After a sulfurization step in a quartz tube at 500 °C under an argon flow for one hour, the samples formed are analyzed by different techniques: X-ray diffraction technique showing characteristic peaks relating to planes (112), (204), (312) (400), and (004) of the CCTS phase, as well as the characteristic peaks located at 290 cm−1 and 325 cm−1 with Raman spectroscopy, and then the effect of copper concentration on the optical properties was identified by UV–Visible spectrophotometry which showed that the optical-gap values are decreased from 1.68 to 1.48 eV when the Cu concentration was varied from 0.015 to 0.030 M. [ABSTRACT FROM AUTHOR]

Natural ventilation performance is one of the key climate control parameters for Canary type greenhouses, which are rapidly expanding along the Atlantic coast in Morocco. The use of insect screens significantly reduces airflow and increases thermal gradients inside the greenhouse. The aim of this study was to analyze the natural ventilation performances in real cultural conditions of a large-scale Canary type tomato greenhouse (1.1 ha) equipped with insect screens on the vent openings. A global energy balance of the greenhouse was used, allowing for the determination of air exchange rates. The greenhouse ventilation performance was compared with those of other greenhouses types and discussed with respect to the improvement of greenhouse vent design, insect screen types, and ridge and crop row orientation. The results confirm the strong dependence of greenhouse ventilation rate on wind speed and ventilation opening location. In addition, results show a significant reduction of the ventilation rate compared with other greenhouse types: the insect screen reduced the greenhouse ventilation rate by 46%, and the tomato rows that were oriented perpendicular to the prevailing air movement through the greenhouse reduced the ventilation rate by 50%. From this analysis, practical improvements are proposed and discussed in the context of protected crop production in the coastal area of Morocco. [ABSTRACT FROM AUTHOR]

The present research study combines chitin from shrimp waste with the oxide-rich metakaolin. Metakaolin is a blend of mixed oxides rich in silica and alumina with good adsorbent properties. The chitin@metakaolin (CHt@M.K.) composite was synthesized and characterized using FTIR, SEM, TGA, XRD and XPS techniques. Cr(VI) removal studies were compared for chitin and CHt@M.K. through adsorption. It was found that the adsorption capacity of CHt@M.K. is 278.88 mg/g, almost double that of chitin, at pH 5.0 in just 120 min of adsorption. Isotherm models like Langmuir, Freundlich, Temkin and Dubinin-Radushkevich were investigated to comprehend the adsorption process. It was revealed that Langmuir adsorption isotherm is most suitable to elucidate Cr(VI) adsorption on CHt@M.K. The adsorption kinetics indicate that pseudo first order was followed, indicating that the physisorption was the process that limited the sorption process rate. The positive enthalpy change (20.23 kJ/mol) and positive entropy change (0.083 kJ/mol K) showed that the adsorption process was endothermic and more random at the solid-liquid interface. The negative free energy change over entire temperature range was an indicator of spontaneity of the process. Apart from all these, the non-covalent interactions between Cr(VI) and composite were explained by quantum calculations based models., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Nitrates level in water is a worldwide problem that represents a risk to the environment and people's health; efforts are currently devoted to the development and implementation of new biomaterials for their removal. In this study, chitosan (Ch) from shrimp waste and the related epichlorohydrin-modified crossover chitosan (Ch-EPI) were used to remove nitrates from aqueous solutions. The mechanism of selective nitrate removal was elucidated and validated by theoretical calculations. The physicochemical performance of Ch and Ch-EPI was investigated through the main parameters pH, adsorption capacity, contact time, initial nitrate concentration, coexisting anions, and temperature. The experimental data were fitted to widely used adsorption kinetic models and adsorption isotherms. The maximum percentage of nitrate adsorption was reached at an equilibrium pH of 4.0 at an adsorbent dose of 2.0 g/L after a contact time of 50 min. Competing anion experiments show that chloride and sulfate ions have minimal and maximal effects on nitrate adsorption by Ch-EPI. Experimental adsorption data are best fitted to pseudo-second-order kinetic and isothermal Langmuir models. The maximum adsorption capacities of Ch and Ch-EPI for nitrate removal were 12.0 mg/g and 38 mg/g, respectively., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This work synthesized a novel chitosan-loaded MgAl-LDH (LDH = layered double hyroxide) nanocomposite, which was physicochemically characterized, and its performance in As(V) removal and antimicrobial activity was evaluated. Chitosan-loaded MgAl-LDH nanocomposite (CsC@MgAl-LDH) was prepared using cross-linked natural chitosan from shrimp waste and modified by Mg-Al. The main mechanisms predominating the separation of As(V) were elucidated. The characteristic changes confirming MgAl-LDH modification with chitosan were analyzed through Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis-differential thermal analysis, and Brunauer-Emmett-Teller measurements. Porosity and the increased surface area play an important role in arsenic adsorption and microbial activity. Adsorption kinetics follows the general order statistically confirmed by Bayesian Information Criterion differences. To understand the adsorption process, Langmuir, Freundlich, and Liu isotherms were studied at three different temperatures. It was found that Liu's isotherm model was the best-fitted model. CsC@MgAl-LDH showed the maximum adsorption capacity of 69.29 mg g -1 toward arsenic at 60 °C. It was observed that the adsorption capacity of the material rose with the increase in temperature. The spontaneous behavior and endothermic nature of adsorption was confirmed by the thermodynamic parameters study. Minimal change in percentage removal was observed with coexisting ions. The regeneration of material and adsorption-desorption cycles revealed that the adsorbent is economically efficient. The nanocomposite was very effective against Staphylococcus aureus and Bacillus subtilus ., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

In this work, a cost-effective chitin-based magnesium oxide (CHt@MgO) biocomposite with excellent anionic methyl orange (MO) dye removal efficiency from water was developed. The CHt@MgO biocomposite was characterized by FT-IR, XRD, SEM-EDX, and TGA/DTG. Results proved the successful synthesis of CHt@MgO biocomposite. Adsorption of MO on the CHt@MgO biocomposite was optimized by varying experimental conditions such as pH, amount of adsorbent (m), contact time (t), temperature (T), and initial MO concentration ( C o ). The optimized parameters for MO removal by CHt@MgO biocomposite were as follows: pH, 6; m, 2 g/L; t, 120 min. Two common isotherm models (Langmuir and Freundlich) and three kinetic models (pseudo-first-order (PFO), pseudo-second-order (PSO), and intraparticle diffusion (IPD)) were tested for experimental data fitting. Results showed that Langmuir and PFO were the most suitable to respectively describe equilibrium and kinetic results on the adsorption of MO adsorption on CHt@MgO biocomposite. The maximum Langmuir monolayer adsorption capacity ( q m ) on CHt@MgO biocomposite toward MO dye was 252 mg/g at 60 °C. The reusability tests revealed that CHt@MgO biocomposite possessed high (90.7%) removal efficiency after the fifth regeneration cycle.

Chitosan (Cs)-based composites were developed by incorporating silica (Cs-Si), and both silica and hydroxyapatite (Cs-Si-Hap), comparatively tested to sequester hexavalent (Cr(VI)) ions from water. XRD and FT-IR data affirmed the formation of Cs-Si and Cs-Si-Hap composite. Morphological images exhibits homogeneous Cs-Si surface, decorated with SiO 2 nanoparticles, while the Cs-Si-Hap surface was non-homogeneous with microstructures, having SiO 2 and Hap nanoparticles. Thermal analysis data revealed excellent thermal stability of the developed composites. Significant influence of pH, adsorbent dose, contact time, temperature, and coexisting anions on Cr(VI) adsorption onto composites was observed. Maximum Cr(VI) uptakes on Cs and developed composites were observed at pH 3. The equilibration time for Cr(VI) adsorption on Cs-Si-Hap was 10 min, comparatively better than Cs and Cs-Si. The adsorption data was fitted to pseudo-second-order kinetic and Langmuir isotherm models with respective maximum monolayer adsorption capacities (q m ) of 55.5, 64.4, and 212.8 mg/g for Cs, Cs-Si, and Cs-Si-Hap. Regeneration studies showed that composites could be used for three consecutive cycles without losing their adsorption potential.

Herein, a chitosan (CH) and fluroapatite (TNP) based CH-TNP composite was synthesized by utilizing seafood waste and phosphate rock and was tested for divalent copper (Cu(II)) adsorptive removal from water. The XRD and FT-IR data affirmed the formation of a CH-TNP composite, while BET analysis showed that the surface area of the CH-TNP composite (35.5 m 2 /g) was twice that of CH (16.7 m 2 /g). Mechanistically, electrostatic, van der Waals, and co-ordinate interactions were primarily responsible for the binding of Cu(II) with the CH-TNP composite. The maximum Cu(II) uptake of both CH and CH-TNP composite was recorded in the pH range 3-4. Monolayer Cu(II) coverage over both CH and CH-TNP surfaces was confirmed by the fitting of adsorption data to a Langmuir isotherm model. The chemical nature of the adsorption process was confirmed by the fitting of a pseudo-second-order kinetic model to adsorption data. About 82% of Cu(II) from saturated CH-TNP was recovered by 0.5 M NaOH. A significant drop in Cu(II) uptake was observed after four consecutive regeneration cycles. The co-existing ions (in binary and ternary systems) significantly reduced the Cu(II) removal efficacy of CH-TNP.