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In this work, for the first time, the sorption behaviour of platinum and palladium on polyethylene microplastics (PE-MP) was studied. To simulate natural conditions, part of PE-MP was subjected to the ageing process in lake water under the influence of solar radiation. The original and aged PE-MP was characterised using elemental analysis, FT-IR, SEM-EDX, and nitrogen porosimetry methods. The studies on Pt and Pd sorption on PE-MP were carried out in batch mode in natural lake water at pH 7.6. It was found that the ageing process led to the degradation of the surface of the PE-MP and the formation of a biofilm. The sorption process of Pt and Pd on PE-MP particles proceeds according to pseudo-second-order kinetics. A good fit of the experimental data to the Freundlich and Langmuir isotherm model indicates the mixed nature of Pt and Pd sorption on PE-MP. It was clearly indicated that Pt and Pd sorption from natural waters can occur on the surface of inert polyethylene particles, which can lead to the preconcentration of these elements, even from waters with a very low content, and transferring them over longer distances. This poses a threat to the health of living organisms and humans. [ABSTRACT FROM AUTHOR]

Black soldier fly larvae (BSFL) are gaining attention as an alternative protein source in food and feed, promoting a circular economy, particularly in their dried form. In the literature, monitoring the behavior of larvae in a humid environment has not been established under different conditions of temperature and relative humidity as well as the quality of dried larvae is not always correlated to the conditions of drying. Therefore, this study comprehensively analyses the adsorption–desorption isotherms, drying kinetics, and subsequent quality changes of dried BSFL. Sorption isotherms were assessed at 40, 50, 60, and 70 °C using the gravimetric method, followed by mathematical modelling and determination of thermodynamic variables. Thin-layer drying kinetics were studied in a forced-air oven at the same temperatures, with a subsequent proximate analysis of the dried larvae. Among eight sorption isotherm models evaluated, the Peleg model provided the best fit, revealing type II sorption isotherms with an optimal storage water activity of 0.38. The Page model accurately described the drying kinetics of BSFL across all temperatures. Moisture diffusion coefficients ranged from 6.15 × 10–11 to 2.63 × 10–10 m2/s, with an activation energy of 48.66 kJ/mol. The dried larvae displayed impressive protein levels, varying from 39.67 ± 0.28% to 45.29 ± 0.07%, exceeding the minimum requirements set in the global insect production industry. Higher drying temperatures significantly impacted the proximate composition, reducing larvae quality. These findings underscore the potential of BSFL as a valuable protein source and enhance the understanding of their sorption behavior and quality attributes during drying. This study contributes to the optimization of drying conditions for improving the quality of BSFL as a sustainable protein alternative. [ABSTRACT FROM AUTHOR]

The contribution of organic matter content to the hydrosorption properties of soils is demonstrated. Hydrosorption properties were studied for soils of different genesis and with different degrees of technogenic load. Among technogenic soils, urban and arable soils are considered. Natural soils are represented by soddy eluvial metamorphic on varved clays (Albic Stagnic Retisol (Siltic)), gray metamorphic (Luvic Greyzemic Phaeozem (Clayic, Humic)) and clayey illuvial chernozem (Luvic Chernozem (Clayic, Humic)) on brown clays. Sorption isotherms constructed using the BET method and the specific surface areas of the initial samples and samples after organic matter destruction were compared. Organic matter was destroyed in a laboratory experiment using hydrogen peroxide. It has been revealed that treatment with H2O2 led to a significant decrease in the sorption capacity of soils and a change in hysteresis phenomena. At the same time, the sorption capacity of the soils decreased differently. The specific surface area decreased from 1.9 to 2.8 times. Statistical analysis has shown no correlation between the degree of reduction in specific surface area and the degree of reduction in organic matter content. However, a close correlation has been found between the degree of reduction in specific surface area and the initial organic matter content. The higher the initial organic matter content of the soil, the greater the reduction in specific surface area as a result of the treatment. It has been revealed that treatment with H2O2 has the most significant effect on equilibrium water contents in the capillary condensation interval. The sorption capacity of the urban soils was lower than that of their natural and arable counterparts. At a relatively high organic carbon content in urban soils, its destruction had a lower effect on the specific surface than that in other soils, which suggests that it is related to the qualitative composition of the organic matter. [ABSTRACT FROM AUTHOR]

In this study, four types of "Juá" stem barks (Ziziphus joazeiro) were investigated for the removal of Cu(II) from aqueous solutions. The tested samples included natural coarse barks, and barks washed with water, ethanol–water, and NaOH solutions. The solvent-modified materials simulated the waste of the industrial extraction of saponins from bark. The valorization of these processing residues as sorbents was evaluated. The NaOH-washed sorbent exhibited the highest sorption capacity for Cu(II) (maximum sorption capacity ≈ 32 mg g−1). Ion exchange process between copper and exchangeable surface cations and electrostatic attraction of copper with carboxylate and phenolate groups were identified as the primary sorption mechanisms. Desorption tests revealed that a large portion of the metal sorbed (80%) was easily released from the sorbent thus suggesting, in line with the proposed mechanisms, the existence of weak sorbate-sorbent interactions. The sorptive process was found to be exothermic (∆H° = − 48.1 ± 13.5 kJ.mol−1) and thermodynamically favorable at lower temperatures. [ABSTRACT FROM AUTHOR]

The addition of carbon-rich materials, such as raw feedstocks (RAW) and biochars, to agricultural soils is on the rise. This activity has many advantages, such as improving fertility, increasing water retention, and sequestering carbon. However, they can also increase the sorption of residual herbicides in the soil, reducing the effectiveness of weed control. Thus, the objective of this study was to evaluate soil improvement and the sorption–desorption process of diclosulam in soil unamended and amended with RAW from olive stone and their biochars produced in two pyrolysis temperatures (300 and 500 °C). Oxisol was used in this study, unamended and amended with RAW and biochars (BC300 and BC500) in a rate of 10% (w w−1). The sorption–desorption process was assessed by batch-equilibrium experiments and the analysis was performed using high-performance liquid chromatography (HPLC). The addition of the three materials to the soil increased the contents of pH, organic carbon, P, K, Ca, Mg, Zn, Fe, Mn, Cu, B, cation exchange capacity, base saturation and decreased H + Al. The unamended soil had Kf (Freundlich sorption coefficient) values of diclosulam sorption and desorption of 1.56 and 12.93 mg(1 − 1/n) L1/n Kg−1, respectively. Unamended soil sorbed 30.60% and desorbed 13.40% of herbicide. Soil amended with RAW, BC300, and BC500 sorbed 31.92, 49.88, and 30.93% of diclosulam and desorbed 13.33, 11.67, and 11.16%, respectively. The addition of RAW and biochars from olive stone has the potential to change the soil fertility, but does not interfere with the bioavailability of diclosulam in weed control under field conditions, since the materials slightly influenced or did not alter the sorption–desorption of diclosulam. [ABSTRACT FROM AUTHOR]

Polyethylene (PE) and other polymers are widely and successfully used as passive samplers for organic pollutants in the environment. This study provides high-resolution experimental data from batch shaking tests on the uptake, reversibility, and linear equilibrium partitioning of polycyclic aromatic hydrocarbons (PAHs) using two different PE sheets of 30 µm and 80 µm thickness. Kinetics for phenanthrene are well described by a mechanistic first-order model with mass transfer limited by an aqueous boundary layer (with a mean thickness of 170 µm). Equilibration in laboratory batch systems during uptake and desorption is very rapid with characteristic times of 1–2 h but this depends on the boundary condition, e.g., the ratio of PE mass to water volume. Therefore, equilibration of PE in other setups, e.g., in soil slurries or sediment suspensions, may take orders of magnitude longer because the boundary condition for PE changes from finite to infinite bath conditions (soil or sediment particles may keep the concentration in water almost constant). Solid precipitates for high molecular weight PAHs explain partition coefficients below expected values because of kinetic limitations in such a system. Nevertheless, passive sampling can be employed safely if such limitations are considered; furthermore, partition coefficients can be estimated accurately by empirical relationships (e.g., within 0.1 log unit) based on molecular weight, octanol/water partition coefficients, or subcooled liquid solubilities. [ABSTRACT FROM AUTHOR]

Abstract Background The widely adopted use of charred biomass for agronomic and environmental purposes; and the reported positive and deleterious effects necessitated the need for this study to ascertain the potential causes of the erratic results surrounding the use of charred biomass in agriculture and the environment. A batch sorption experiment was carried out to determine the sorptive and desorptive capacity of bone char and biochar on nitrate, ammonium, phosphate and sulphate concentrations in a loamy sand soil. The potential agronomic and environmental implications of the sorption data were also discussed. Results The results indicated that bone char is richer in nutrient composition than biochar, with 70% more ability to sorb nutrients. The bone char and biochar sorption isotherms conformed to the H-curve isotherm type. Bone char and biochar have multiple layers of adsorption sites. Nutrient adsorption maxima, binding energy, and maximum buffering capacities of the soil were increased with the addition of bone char and biochar. The unamended soil was observed to retain as low as 6% of added nitrate to as much as 58% of added phosphate, while bone char retained 56% of added sulphate, 47% of phosphate, 76% nitrate and 64% of ammonium. Generally, bone char retained 60.6% of the added nutrients, while biochar retained 40.7% of the nutrients. The addition of bone char led to a 45.8% increase in the nutrient retention ability of the soil and a 36.1% increase with the addition of biochar. Conclusion The nutrient sorption characteristics of biochar should be studied prior to its use as a soil nutrient amendment. It was concluded that bone char or biochar is a potential soil nutrient immobilizer; hence, applications for agronomic purposes should take cognizance of the native soil fertility so as to appropriately add fertilizer input before use.

Background: The widely adopted use of charred biomass for agronomic and environmental purposes; and the reported positive and deleterious effects necessitated the need for this study to ascertain the potential causes of the erratic results surrounding the use of charred biomass in agriculture and the environment. A batch sorption experiment was carried out to determine the sorptive and desorptive capacity of bone char and biochar on nitrate, ammonium, phosphate and sulphate concentrations in a loamy sand soil. The potential agronomic and environmental implications of the sorption data were also discussed. Results: The results indicated that bone char is richer in nutrient composition than biochar, with 70% more ability to sorb nutrients. The bone char and biochar sorption isotherms conformed to the H-curve isotherm type. Bone char and biochar have multiple layers of adsorption sites. Nutrient adsorption maxima, binding energy, and maximum buffering capacities of the soil were increased with the addition of bone char and biochar. The unamended soil was observed to retain as low as 6% of added nitrate to as much as 58% of added phosphate, while bone char retained 56% of added sulphate, 47% of phosphate, 76% nitrate and 64% of ammonium. Generally, bone char retained 60.6% of the added nutrients, while biochar retained 40.7% of the nutrients. The addition of bone char led to a 45.8% increase in the nutrient retention ability of the soil and a 36.1% increase with the addition of biochar. Conclusion: The nutrient sorption characteristics of biochar should be studied prior to its use as a soil nutrient amendment. It was concluded that bone char or biochar is a potential soil nutrient immobilizer; hence, applications for agronomic purposes should take cognizance of the native soil fertility so as to appropriately add fertilizer input before use. [ABSTRACT FROM AUTHOR]

The sorption of certain lanthanides from aqueous solutions is the focus of this work using antimony oxide (Sb2O5) sorbent. Sb2O5 sorbent was prepared using the precipitation technique, and it has been described using several analytical methods such as Fourier-transformed infrared (FT-IR), X-ray diffraction pattern (XRD), and scanning electron microscope (SEM). The sorption data were collected on Y(III), Ce(III), and Gd(III) including the effects of pH, shaking time, initial metal concentrations, and temperature. The results revealed that saturation capacity has values of (30.6, 27.5, and 24.1 mg/g) for Y(III), Ce(III), and Gd(III), respectively. The sorption of the studied cations is dependent on pH. The reaction kinetics obeyed the pseudo-2nd-order model, and thermodynamics was endothermic and spontaneous. Sorption isotherms are more relevant to a Langmuir isotherm, whose monolayer capacity values are 27.9, 23.2, and 19.8 mg/g for Y(III), Ce(III), and Gd(III), respectively. The real sample applications illustrate the superiority of antimony oxide sorbent in the removal of Y(III), Ce(III), and Gd(III) from high-grade monazite (HGM). [ABSTRACT FROM AUTHOR]

To increase the biodiversity of agricultural systems, aromatic plants appear particularly promising as additional perennial crops in intercropping. They produce essential oils that contain monoterpenes, for example. These compounds have antibiotic properties that make them interesting for commercialisation as medicinal or pesticide products, but also carry the risk of undesirable effects on soil microorganisms and thus on essential soil functions. To investigate this, the monoterpenes thymol and carvacrol and a set of four typical agricultural soils were selected and soil sorption batch tests and soil toxicity tests were carried out to determine dose-response relationships. Sorption followed second order kinetics and was best described at equilibrium by the non-linear BET isotherm that distinguishes between monolayer and multilayer sorption of the non-polar compounds. While the kinetics were very fast with rate constants of 1.66 × 10-4 and 0.70 × 10-4 min-1 for thymol and carvacrol, the strength of sorption remained quite low (Kd 1.93-3.69), indicating a high mobility and bioavailability of the monoterpenes. In addition, the relation to single soil properties remained low, indicating a multivariate impact of several soil properties. Although thymol and carvacrol are isomeric compounds, they differed in the rate and strength of sorption as well as in the effects on five selected soil microbiological enzyme activities. In particular, carvacrol caused inhibition of enzyme activities, whereas thymol did not produce measurable or relevant effects in all cases. The effect concentrations of 10% and 25% percent inhibition (EC10, EC25) ranged from <1 µg to several grams per Gram of soil and hormesis effects were also observed at low concentrations. On the one hand, this indicates only low toxicity; on the other hand, several of the defined effect thresholds can be reached or exceeded by expected environmental concentrations. This may harbour a risk of adverse effects, but may also have a phytosanitary effect, which requires further research. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the use of zwitterionic microparticles as new and efficient macromolecular supports for the sorption of an antibiotic (doxycycline hydrochloride, DCH) from aqueous solution. The effect of relevant process parameters of sorption, like dosage of microparticles, pH value, contact time, the initial concentration of drug and temperature, was evaluated to obtain the optimal experimental conditions. The sorption kinetics were investigated using Lagergren, Ho, Elovich and Weber–Morris models, respectively. The sorption efficiency was characterized by applying the Langmuir, Freundlich and Dubinin–Radushkevich isotherm models. The calculated thermodynamic parameters (ΔH, ΔS and ΔG) show that the sorption of doxycycline hydrochloride onto zwitterionic microparticles is endothermic, spontaneous and favorable at higher temperatures. The maximum identified sorption capacity value is 157.860 mg/g at 308 K. The Higuchi, Korsmeyer–Peppas, Baker–Lonsdale and Kopcha models are used to describe the release studies. In vitro release studies show that the release mechanism of doxycycline hydrochloride from zwitterionic microparticles is predominantly anomalous or non-Fickian diffusion. This study could provide the opportunity to expand the use of these new zwitterionic structures in medicine and water purification. [ABSTRACT FROM AUTHOR]

Powdered rock phosphate may have the potential of soluble phosphate sorption because its particles are small. Phosphorus (P) sorption-desorption behavior and sorption kinetics were studied on four different fine powdered phosphate rocks (PPR), from Esfordi, Chadormalu and Yasuj mines. Sorption isotherms were evaluated by equilibrating 1 g PPR with 20 ml CaCl2- 0.01 M containing 10, 50, 100, 200, 400, 600, 800 and 1000 mg P L-1, as KH2PO4 in duplicates. Consequently, P release was studied by equilibrating the samples with 20 ml 0.01 M CaCl2. FTIR analysis was conducted on the blank samples, and those equilibrated with 1000 mg P L-1. Kinetics of phosphate sorption on PPRs was evaluated with two initial P concentrations (50 and 100 mg P L-1) and contact times of 1, 2, 4, 8, 16, 24, and 48 h with 0.01 M CaCl2 as the background solution in duplicate. Results showed that the least P sorption was around 150, and the maximum P sorption was 12000 mg kg-1 PPRs. The highest P release was around 15% of sorbed P, and releasable P was reduced to 2-3% of sorbrd P with the increase of P sorption. P sorption data showed a good fit with Freundlich and Langmuir equations. The kinetic of P sorption showed a fast reaction that rapidly diminished soluble P. Results of the present study suggest that PPRs could reduce soluble P, which is better to be considered at different usage of PPR such as incorporation with organic wastes and its biosolubilization. [ABSTRACT FROM AUTHOR]

Recent literature has exhibited a growing interest in the utilization of ground glass powder (GP) as a supplementary cementitious material (SCM). Yet, the application of SCMs in stabilizing heavy metallic and metalloid elements remains underexplored. This research zeroes in on zinc stabilization using a binder amalgam of GP and ordinary Portland cement (OPC). This study juxtaposes the stability of zinc in a recomposed binder consisting of 30% GP and 70% OPC (denoted as 30GP-M) against a reference binder of 100% CEM I 52.5 N (labeled reference mortar, RM) across curing intervals of 1, 28, and 90 days. Remarkably, the findings indicate a heightened kinetic immobilization of Zn at 90 days in the presence of GP—surging up to 40% in contrast to RM. Advanced microstructural analyses delineate the stabilization locales for Zn, including on the periphery of hydrated C3S particles (Zn–C3S), within GP-reactive sites (Si*–O–Zn), and amid C–S–H gel structures, i.e., (C/Zn)–S–H. A matrix with 30% GP bolsters the hydration process of C3S vis-à-vis the RM matrix. Probing deeper, the microstructural characterization underscores GP's prowess in Zn immobilization, particularly at the interaction zone with the paste. In the Zn milieu, it was discerning a transmutation—some products born from the GP–Portlandite reaction morph into GP–calcium–zincate. [ABSTRACT FROM AUTHOR]

Although tin mining activities in the southern part of Thailand have been abandoned for more than 40 years, arsenic contamination in old tin-mining areas continues to pose a health risk. Fortunately, natural adsorption of arsenic by sediment has reduced the arsenic concentration in water to the maximum allowable level within a 10-kilometre radius of the mine sources. This article attempts to characterize the arsenic adsorption properties of sediment along a water creek which passes through the old tin-mine areas in Ron Phibun district, Nakhon Si Thammarat province, Thailand, where the contamination has been most severe. It was found that Fe tends to be associated with the adsorption capacity of arsenic in sediment. However, pH 4 and pH 7 did not associate with adsorption capacity. At pH 12, the solubility of arsenic increases, making it less likely to be adsorbed into the sediment and more likely to dissolve in water. For the adsorption isotherms of the sediment, the so-called '2-step Langmuir/Freundlich models', with the advance of switching functions (Logistic or Arctan functions), were proposed. Then, based on the principle of parsimony, a stepwise model reduction approach was used to choose the optimal models. It was found that the isotherms were used successfully to describe the historical arsenic-contamination data of the past 14 years (2005 - 2019) and to predict future trends qualitatively. [ABSTRACT FROM AUTHOR]

This study investigates the applicability of the Peleg model to the osmotic dehydration of various sweet potato variety samples in sugar beet molasses, addressing a notable gap in the existing literature. The osmotic dehydration was performed using an 80% sugar beet molasses solution at temperatures of 20 °C, 35 °C, and 50 °C for periods of 1, 3, and 5 h. The sample-to-solution ratio was 1:5. The objectives encompassed evaluating the Peleg equation's suitability for modeling mass transfer during osmotic dehydration and determining equilibrium water and solid contents at various temperatures. With its modified equation, the Peleg model accurately described water loss and solid gain dynamics during osmotic treatment, as evidenced by a high coefficient of determination value (r2) ranging from 0.990 to 1.000. Analysis of Peleg constants revealed temperature and concentration dependencies, aligning with previous observations. The Guggenheim, Anderson, and de Boer (GAB) model was employed to characterize sorption isotherms, yielding coefficients comparable to prior studies. Effective moisture diffusivity and activation energy calculations further elucidated the drying kinetics, with effective moisture diffusivity values ranging from 1.85 × 10−8 to 4.83 × 10−8 m2/s and activation energy between 7.096 and 16.652 kJ/mol. These findings contribute to understanding the complex kinetics of osmotic dehydration and provide insights into the modeling and optimization of dehydration processes for sweet potato samples, with implications for food processing and preservation methodologies. [ABSTRACT FROM AUTHOR]

Chloride binding by the hydrate phases of cementitious materials influences the rate of chloride ingress into these materials and, thus, the time at which chloride reaches the steel reinforcement in concrete structures. Chloride binding isotherms of individual hydrate phases would be required to model chloride ingress but are only scarcely available and partly conflicting. The present study by RILEM TC 283-CAM 'Chloride transport in alkali-activated materials' significantly extends the available database and resolves some of the apparent contradictions by determining the chloride binding isotherms of layered double hydroxides (LDH), including AFm phases (monosulfate, strätlingite, hydrotalcite, and meixnerite), and of alkali-activated slags (AAS) produced with four different activators (Na2SiO3, Na2O·1.87SiO2, Na2CO3, and Na2SO4), in NaOH/NaCl solutions at various liquid/solid ratios. Selected solids after chloride binding were analysed by X-ray diffraction, and thermodynamic modelling was applied to simulate the phase changes occurring during chloride binding by the AFm phases. The results of the present study show that the chloride binding isotherms of LDH/AFm phases depend strongly on the liquid/solid ratio during the experiments. This is attributed to kinetic restrictions, which are, however, currently poorly understood. Chloride binding by AAS pastes is only moderately influenced by the employed activator. A steep increase of the chloride binding by AAS occurs at free chloride concentrations above approx. 1.0 M, which is possibly related to chloride binding by the C–(N–)A–S–H gel in the AAS. [ABSTRACT FROM AUTHOR]

Sustainable methods such as convective drying have regained interest in reducing the loss and waste of food produce. Combined with techniques like blanching and edible coatings, they could serve as useful tools in food processing development. Composite coatings comprising pectin, soy protein isolate, and xanthan gum were optimized using response surface methodology with the Box–Behnken design. This optimization aimed to investigate their effects on the moisture content, water activity, total color, and rehydration ratio of fresh and blanched chayote slices. Additionally, the study explored the modeling of the drying kinetics and sorption isotherms of chayote (Sechium edule) slices. Soy protein and xanthan gum were found to primarily influence the moisture content (ranging from 5.44% to 9.93%), and pectin influenced water activity (033 to 0.53) of the fresh-coated chayote, while pectin affected the aw (2.13–8.28) and rehydration of the blanch-coated chayote. The optimized formulations for both fresh and blanched chayote were utilized to assess the drying kinetics behavior and sorption isotherms. The best fit (R2: 0.996 to 0.999) was achieved with the parabolic model for thin-layer materials. Furthermore, the sorption isotherms of chayote displayed a Type IV behavior, with the BET model being the most suitable for describing the sorption behavior of materials with low water activity. The predicted values offer valuable data for optimizing processing conditions to enhance the quality and stability of dried chayote. [ABSTRACT FROM AUTHOR]

This paper aimed at determining the quantity, nature and role of extracts during the sorption behavior of two Central African hardwood species: Nauclea diderrichii (Bilinga) and Erythrophleum suaveolens (Tali) at 30, 40, 50, 60 and 70°C using relative humidities (RH) between 5.3% and 97%. For this purpose, extract contents and their nature were determined by solvent extraction and mass spectrometric analysis (MALDI-TOF/MS) respectively. The ABC model whose parameters were used to determine the monolayer moisture capacity (EMCm) also described type II sigmoidal sorption isotherms. The results showed that acetone extracts were the highest in Tali (7.88%) and Bilinga (6.92%). MALDI-TOF results found 10 new chemical components out of 24 in Tali (saponins, flavonoids, glycosides, alkaloids and stilbenes) while 16 were identified as saponins, acids and flavonoids in Bilinga. Acetone-soluble extracts had the most significant effect on the hygroscopic nature of wood. Extracted wood recorded higher equilibrium moisture contents (EMC), monolayer moisture capacities and lower sorption differences. For native wood, water-repellent polyphenols like alkaloids and stilbenes and newly identified components there in, rendered Tali less hygroscopic than Bilinga. The nature of extractives would be an effective alternative to explore the chemical compounds, which can best improve the hygroscopic response of wood. [ABSTRACT FROM AUTHOR]

Conditions of sorption equilibrium of copper, zinc, cadmium and lead-ions by chelatforming resins Amberlite IRC-748 and Duolite C 467 depending on the degree of neutralization of their ionogenic groups, the acidity of the medium and concentration of solutions were studied. Sorption isotherms were established, Langmuir and Freundlich models were proposed. In all cases, the selectivity is governed by the enthalpy factor with heat release and entropy reduction. Changing the experimental conditions (without interruption and with interruption) significantly affects the rate of ion sorption by the studied ion exchangers. This allows us to conclude that internal diffusion plays a significant role in the processes under study. Thermodynamic of these processes is considered at ideal ionite phase - the activity coefficients of absorbed ions in a solid phase haven't been taken into account. The calculated values of the diffusion coefficient, activation energy, activation entropy, enthalpy, free energy and entropy multiplier of all studied processes are given. [ABSTRACT FROM AUTHOR]

Regulation of the equilibrium of ion exchange processes on inorganic sorbents refers to the control of the sorption capacity and selectivity of the sorbent by regulating equilibrium conditions such as temperature, pH, concentration of sorbate, and other competing ions. By controlling these factors, it is possible to control the sorption of ions on inorganic ion exchangers for various applications, such as water purification, chemical separation, and the separation of individual ions from natural or process solutions. The ion exchange isotherm is the equation that describes the equilibrium of the ion exchange process during the absorption (sorption) or release (desorption) of specific ions from an aqueous solution. It determines the equilibrium of the ion exchange process, both sorption and desorption, connecting the amount of transfer of a substance from the aqueous medium to the solid phase at constant pressure, temperature, pH, and other external and internal conditions. This article discusses three methods for reversing ion exchange processes on inorganic sorbents. The first of them is based on a change in the charge of the sorbent matrix, the second on the use of complexing agents, and the third on displacement and equilibrium through the use of salts of weak acids or weak bases. The influence of the buffer properties of a solution on the equilibrium of ion exchange on inorganic sorbents was studied. Based on these ideas, methods have been developed to regulate the equilibrium of sorption processes on inorganic sorbents based on the binding of one of the ions participating in the sorption process into a weakly dissociating compound and changing the charge of the sorbent matrix. An essential factor in the operation of inorganic ion exchange sorbents is the potential for chemical destruction of inorganic sorbents under the influence of external and internal factors. The most radical measures to reduce these losses can be taken when selecting the starting compound for the sorbent manufacture and at the chemical synthesis stage. These factors are considered using the example of lithium-selective sorbents based on manganese oxide, which exhibits structural and external aspects of chemical instability. Their example shows the possibility of controlling the properties of such sorbents from the point of view of their chemical stability. The influence of the Jahn-Teller effect on the chemical stability of inorganic ion-exchange sorbents based on manganese oxide compounds selective for lithium ions was determined. Based on these studies, methods were proposed and tested to ensure the multi-cycle operation of highly selective inorganic ion exchange materials. [ABSTRACT FROM AUTHOR]

Agglomeration is a technological process that is widely applied to obtain powdered products with the appropriate shape and particle size and different physical characteristics and stabilities. The purpose of this research was to study the influences of the composition and storage of powdered infant formulas on their thermal behaviours, as analysed by differential scanning calorimetry (DSC); fatty acid compositions, as determined by gas chromatography; and water activity and water content. This study investigated the influence of the storage time (six months) at temperatures of 20–22 °C and air humidities of 42–45% on powder mixtures and agglomerates. The isotherms of the agglomerates presented a shape and course similar to those of the isotherms of the mixtures from which they were obtained. The agglomeration process affected the stability of the fatty acids in the stored powdered infant formulas. The composition of the fatty acids changed during the storage process. The thermal properties of the powdered infant formulas were not significantly influenced by agglomeration. The compositions of the mixtures and agglomerates influenced the shape and course of the DSC diagrams. Using the DSC method, it was determined whether the fat was a natural component of the powder or it was added in the form of fatty acid preparations. Differences were observed between the shape and course of the DSC curves (heating and cooling) obtained for fresh and 6-month-stored mixtures and agglomerates. [ABSTRACT FROM AUTHOR]

In the frame of this work, the experimental analysis of the reconstitution properties, sorption isotherms and the Fourier-transform infrared spectroscopy (FTIR) spectra of maltodextrin powder was carried out. Before the analysis the substance was dried by standard spray drying method or flame spray drying (FSD). During the analyses, the influence of the applied FSD parameters on the analyzed properties was also estimated. The powders dried using the standard spray dryer were characterized by a better wettability parameter, which was related to a high bulk density. A shorter solubility time was obtained for powders dried by the FSD method, which may be explained by the larger particle diameters. Analyzing maltodextrin powders dried with the FSD, a significant influence of the atomization pressure and particle size on the wettability parameter was found. Application of FSD method does not affect the sorption characteristics of maltodextrin and does not change significantly the chemical structure of the material, since characteristic peaks of FTIR spectra were preserved after the FSD. [ABSTRACT FROM AUTHOR]

In this study, the thermal transition of seaweed Saccharina latissima (raw and blanched) during drying and quality stabilization was considered in view of understanding physico-chemical changes, color changes, sorption changes and thermal property changes with respect to drying kinetics. The variations in the effective moisture diffusivity coefficient with shrinkage changes and temperature lie between 1.0 and 5.0 × 10−10 m2 s−1 (raw) and 0.5 and 3.6 × 10−10 m2 s−1 (blanched), respectively. Noticeable physical and chemical changes were observed during longer drying times, especially in the case of blanched seaweeds. At the temperature of 38.0 °C, a more yellow-colored product was obtained from raw form input materials. The blanched seaweeds accumulated moisture in a linear manner with an increase in the relative humidity of the drying air in the range of 20.0~80.0%, which resulted in high level of hysteresis between the sorption and desorption behavior. Shrinkage changes during the drying of blanched and raw samples were also calculated. The thermal stabilization of raw and blanched forms started at different initial moisture contents showed changed glass transition phenomena during a wide range of temperature sand one melting endotherm between 141.9 and 167.9 °C. Some glass transitions were driven by the presence of water-soluble contents in the material. The dried seaweeds at low temperatures showed a partial glassy state and an amorphous/crystalline state. This study evaluated the effects of process parameters on the properties of dried product. [ABSTRACT FROM AUTHOR]

Currently, the key trends in the global food market include the rapidly developing functional nutrition industry, which is of great interest to consumers. Inulin is a natural polysaccharide of plant origin, consisting of residues of E-fructofuranose (fructose). The object of the research is inulin extract from Jerusalem artichoke at different humidity levels. It has been established that to intensify the drying process of inulin extract, it is advisable to increase the mass transfer surface, which can be achieved by spraying the initial product, and using volumetric energy supply methods, in particular, radiation energy supply. The important and most energy-intensive stages of drying are carried out in the hygroscopic area of equilibrium humidity of the object of the research, which determines the intensity and mechanism of the dehumidification operation in order to increase the degree of perfection, select rational operating parameters, adapt to the object of the analysis and solve a mathematical model of removal moisture from it. Based on the sorption isotherms and hygroscopic parameters of the inulin extract obtained in preliminary studies, obtained by dehydrating the inulin extract from Jerusalem artichoke (variety «Skorospelka», grown by JSC «Chaganskoe», the bAstrakhan region), a thermodynamic analysis of the process of sorption and desorption was carried out in different ranges of humidity variation. The total binding energy of moisture with the dry residue of inulin and its thermodynamic components were found. The data obtained do not contradict known literature sources and can be recommended when designing processes for removing moisture from inulin extract and designing drying devices.

From the examples of three and four-component polymer–polymer systems characterized by amorphous separation, an original technique for determining the pair parameters of interaction between components based on the sorption isotherms of common solvent vapor, particularly water vapor, has been developed. The possibility of calculating thermodynamic characteristics of multicomponent polymer compositions with specific interactions of functional groups from experimentally obtained sorption isotherms is shown. An algorithm for calculating pair interaction parameters, estimating concentration dependences of chemical potential and Gibbs free energy of mixing, and predicting the phase state of polymer mixtures was presented for the first time for such systems. The technique was tested on the example of systems poly(N-vinylpyrrolidone) (PNVP)–polyethylene glycol (PEG), PNVP–PEG–Poly(acrylic acid) (PAA), poly(N-vinylcaprolactam) (PNVCL)–PEG, and polyvinyl alcohol (PVA)–PEG. [ABSTRACT FROM AUTHOR]

Drying, as alternative process, enhances stability, eases transport, and prolongs storage for fruits and fruit pulps. This study focused on producing açaí foam with 2% emulsifier and comparing it to a control (0% emulsifier), following by drying (60 °C) in a forced air circulation oven. Açaí powder with 2% emulsifier exhibited a higher effective diffusion coefficient (5.35 × 10−4 cm2 s−1) than the without emulsifier counter part (1.41 × 10−4 cm2 s−1). The pores formed after pulp aeration with the emulsifying agent led to a higher diffusion coefficient and a shorter drying time. Sorption isotherms at 25 °C and 35 °C displayed favorable fits for both powders (R2>0.9). Açaí powder with emulsifier demonstrated superior solubility (47.93%) and faster rehydration (168 s) compared to the control (19.72%; 324 s). The use of a 2% emulsifying agent resulted in a porous, dried açaí powder with improved flowability and solubility, indicating higher quality. Practical applications: Traditionally, açai pulp is commercialized as a frozen product, which entails high energy costs and logistical constraints. Foam‐mat drying allows the dehydration of viscous, heat‐sensitive, and high‐sugar foods that cannot be effectively dried through spray drying. It offers a practical application in the food industry, particularly as an ingredient. Powdered fruit pulps, including açai pulp, are widely utilized in ice creams, yogurts, and instant juices. To meet industrial requirements, these powders need to exhibit good solubility, quick rehydration, and stability at room temperature. Through foam‐mat drying, high‐quality powdered açai pulp can be produced with a short drying time. This technology enables the production of stable powders that can be easily rehydrated, opening opportunities for new ingredient development and diverse applications. [ABSTRACT FROM AUTHOR]

The sorption capacity of microplastic in respect of heavy metals (Co, Ni, Cu, Cd, Pb) in the natural water of Lake Onego was investigated. Microplastic particles of polyethylene terephthalate were obtained by grinding a plastic bottle aged in natural conditions. The type of polymer used to produce microplastics and the degree of its destruction were investigated using Scanning electron microscopy with energy dispersive X-ray spectroscopy, Raman spectroscopy and micro Fourier Transform infra-red Spectroscopy. The concentrations of metal additives in the model aqueous solutions for the construction of isotherms were close to those in Lake Onego and its tributaries. Obtained isotherms of metals sorption on the surface of microplastics in natural waters differed from those widely reported in the literature for model solutions based on distilled water. Conventional Langmuir and Freundlich models were able to describe sorption processes in Lake Onego water only within certain ranges of element concentrations, what is primarily due to the presence of natural organic matter and Fe and Mn hydroxides in the water of Lake Onego. [ABSTRACT FROM AUTHOR]

The effect of organic matter (OM) on soil phosphorus (P) sorption is controversial, as there is still no clear answer whether organic matter inhibits or increases P sorption. Despite the great need for renewable sources of available P and OM in agricultural soils, little is known about the interaction between P and dissolved organic matter (DOM) in natural soil systems. The aim of this research was to uncover if and how soil saturation with DOM derived from different types of abundant agricultural wastes (cattle manure, horse manure, biogas digestate, compost) affects the phosphate sorption. We examined the P sorption process in control and DOM-saturated sandy soils. The results indicated that OM introduced with agricultural waste did not always reduce P sorption, but certainly had an effect on impairing P fixation, and thus, may result in potentially greater P mobility in the soil, including P availability. Among these waste materials, DOM from horse manure had the most positive effect on P mobilization; thus, horse manure—if available—is recommended for spreading on soils with low P mobility. [ABSTRACT FROM AUTHOR]

This study investigates the applicability of the Peleg model to the osmotic dehydration of various sweet potato variety samples in sugar beet molasses, addressing a notable gap in the existing literature. The osmotic dehydration was performed using an 80% sugar beet molasses solution at temperatures of 20 °C, 35 °C, and 50 °C for periods of 1, 3, and 5 h. The sample-to-solution ratio was 1:5. The objectives encompassed evaluating the Peleg equation’s suitability for modeling mass transfer during osmotic dehydration and determining equilibrium water and solid contents at various temperatures. With its modified equation, the Peleg model accurately described water loss and solid gain dynamics during osmotic treatment, as evidenced by a high coefficient of determination value (r2) ranging from 0.990 to 1.000. Analysis of Peleg constants revealed temperature and concentration dependencies, aligning with previous observations. The Guggenheim, Anderson, and de Boer (GAB) model was employed to characterize sorption isotherms, yielding coefficients comparable to prior studies. Effective moisture diffusivity and activation energy calculations further elucidated the drying kinetics, with effective moisture diffusivity values ranging from 1.85 × 10−8 to 4.83 × 10−8 m2/s and activation energy between 7.096 and 16.652 kJ/mol. These findings contribute to understanding the complex kinetics of osmotic dehydration and provide insights into the modeling and optimization of dehydration processes for sweet potato samples, with implications for food processing and preservation methodologies.

Migration of moisture and oxygen into packages during storage lead to deteriorative reactions such as nonenzymatic browning (NEB), stickiness, caking, and oxidation. Actual shelf-life testing of milk-millet powders is tedious and time-consuming as they have long storage stability. The aim of this study was to predict the shelf-life of spray-dried milk-millet powders based on deteriorative reactions due to moisture and oxygen uptake, and evaluate whether the prediction models could be applied as an alternative to accelerated or normal shelf-life testing. Fresh cow milk was standardized, concentrated to 22% total solids (TS), blended with millet wort of 22% TS in 1:1 ratio, and dried into powder using a lab-scale co-current type spray dryer. The predicted shelf-life of milk-malted foxtail millet powder based on stickiness and NEB caused by moisture gain was 17 and 30 days in high-density polyethylene (HDPE), 41 and 58 days in EVOH laminate (LDPE/EVOH/LDPE), and 96 and 134 days in polyethylene-terephthalate (PET) laminate (PET/Al foil/PET/LDPE) pouches, respectively. The corresponding shelf-life of milk-barnyard millet powder based on stickiness and NEB was 18 and 30 days, 66 and 96 days, and 90 and 102 days, in HDPE, EVOH laminate, and PET laminate, respectively. Similarly, the predicted oxygen limiting shelf-life based on thiobarbituric acid reactive substances was found to be 40, 75, and 86 days for milk-foxtail millet powder and 32, 72, and 93 days for milk-barnyard millet powder in HDPE, EVOH laminate, and PET laminate, respectively. The rate of deteriorative reactions was the lowest in PET laminate pouches because of its excellent barrier properties over that of HDPE and EVOH even at the adverse accelerated storage conditions. The simulation model was adequate and reliable in predicting the shelf-life of milk-millet powders in packaging materials with wide range of barrier properties. [ABSTRACT FROM AUTHOR]

The interaction of adsorbed water with the microstructure of cementitious materials leads to effects on macroscopic properties. However, precise quantitative correlation of adsorbed water with short‐term changes in macroscopic properties, such as dimensional changes, remains a challenge. We compare recent results from precise dual‐microscope‐based short‐term length change measurements and discuss differences in length‐change isotherms and adsorption isotherms arising from various cement types. Water vapor adsorption happens already at very low humidity in the interlayer space of the C‐S‐H gel. Adsorption and desorption on cement surfaces due to changing relative humidity induces strong forces in the cement gel, leading to detectable changes in dimensional stability for the hardened material. A significant hysteresis in the water desorption isotherm is often accompanied by hysteresis in dimensional change as well. For precise length change measurements, an optical method for tracking surface patterns on thin cement slices was applied. Short‐term length change results are compared to corresponding water vapor sorption isotherms and pore size measurements. Hypotheses and conclusions regarding microstructural changes and shrinkage mechanisms are discussed in order to understand the experimental data. [ABSTRACT FROM AUTHOR]

The stabilization of heavy metals in soils is considered a cost-effective and environmentally sustainable remediation approach. In the current study, the applicability of water treatment residual nanoparticles (nWTRs) with the particle size ranged from 45 to 96 nm was evaluated for its efficacy in reducing arsenic mobility in clayey and sandy contaminated alkaline soils. Sorption isotherms, kinetics, speciation and fractionation studies were performed. Sorption equilibrium and kinetics studies revealed that As sorption by nWTRs-amended soils followed Langmuir and second-order/power function models. The maximum As sorption capacity (qmax) of Langmuir increased up to 21- and 15-folds in clayey and sandy soils, respectively, as a result of nWTRs application at 0.3% rate. A drastic reduction in non-residual (NORS) As fraction from 80.2 and 51.49% to 11.25 and 14.42% for clayey and sandy soils, respectively, at 0.3% nWTRs application rate was observed, whereas residual (RS) As fraction in both studied soils strongly increased following nWTRs application. The decline in percentage of As mobile form (arsenious acid) in both soils after nWTRs application indicated the strong effect of nWTRs on As immobilization in contaminated soils. Furthermore, Fourier transmission infrared spectroscopy analysis suggested reaction mechanisms between As and the surfaces of amorphous Fe and Al oxides of nWTRs through OH groups. This study highlights the effective management approach of using nWTRs as soil amendment to stabilize As in contaminated alkaline soils. [ABSTRACT FROM AUTHOR]

Abstract Evidence for direct adverse effects of micro- and nanoplastic particles (MNPs) on human health is scarce, but it has been hypothesized that MNPs act as carriers for environmental pollutants such as polycyclic aromatic hydrocarbons (PAHs). Many studies have already investigated the sorption of PAHs to microplastics, typically using the batch-equilibrium method. Here we established a novel third-phase partition (TPP) method utilizing thermo-extractable polydimethylsiloxane-coated stir-bars as re-usable passive samplers to compare the sorption of PAHs to 17 different MNPs. This method facilitates the quantification of MNP-sorbed pollutants, including those with poor water-solubility without requiring laborious filtration and solvent-extraction steps. Using benzo[a]pyrene (B[a]P) as a representative PAH, sorption kinetics and isotherms for MNPs were evaluated. B[a]P sorption was generally strong but differed by over two-orders of magnitude, clustering according to polymer types in the order of polyamides > polyethylenes ≫ Tire Rubber > polyurethanes > polymethyl methacrylate. B[a]P sorption was diminished for photo-aged MNPs. Within given polymer types, properties including particle size, polarity/hydrophobicity and chain mobility notably influenced B[a]P sorption. When comparing different PAHs, their sorption to selected MNPs increased over five-orders of magnitude with hydrophobicity: anthracene < B[a]P < dibenzo[a,l]pyrene. Our data is an important contribution to the understanding of the sorption behaviors of MNPs. The novel TPP-method represents a universally-applicable approach for the reliable evaluation of sorption characteristics of contaminants and MNPs, and can be easily adapted to desorption studies. Graphical Abstract

In this study, equilibrium conditions and kinetics of sorption of Cu2+, Zn2+, Cd2+ and Pb2+ ions with Dowex MAC-3 (carboxyl group, H+) cationite were studied, thermodynamic quantities were calculated based on kinetic parameters. It was noted that the kinetics of the processes at the selected concentrations are under internal diffusion control. Sorption isotherms were established, Langmuir and Freundlich models were proposed. In all cases, the selectivity is governed by the enthalpy factor with heat release and entropy reduction. The variation of parameters such as activation energy of sorption, free energy, activation entropy and diffusion coefficients varies due to various factors. In the calculation of thermodynamic parameters, the ideality of the ionic phase was determined, in other words, the activity coefficients of the sorbed ions in the ionic phase were not taken into account. [ABSTRACT FROM AUTHOR]

This research is investigating the moisture adsorbing and desorbing properties of mint powder from Bulgaria. The benefits of taking a functional nutritional supplement are countless, and the purpose of this research is to add and enrich new data concerning the sorption characteristics and to present the economic value of a Bulgarian herbal functional ingredient. A study was conducted on mass transfer in moisture at different temperatures (10 0C, 25 0C, and 40 0C) and with different water activities (0.1 to 0.9). The conditions chosen were similar to the manufacturers recommended and preferred storage conditions. The results of the study were described using four different models (Oswin, Chung-Pfost, Henderson and Halsey), and rated with mean relative error and standard deviation. The moisture content of a monolayer was predicted using a linearization of a Brunauer-Emmett-Teller model. The adsorption and desorption isotherms were classified as type 2 according to Brunauer's classification. This research approved that in the condition of constant water activity with decrease of temperature increase the equilibrium moisture content. For the Adsorption process the equilibrium moisture content is in the range from 6.33% d.b. to 27.14% d.b. and for the desorption process from 6.23% d.b. to 24.82% d.b. The best model for fit the isotherms is the modified Chung-Pfost elected through mean relative error and standard deviation. The obtained values for monolayer moisture content for each food product are strictly individual, such as for the mint powder: the adsorption from 9.99% d.b. to 11.51% d.b., the desorption process from 8.40% d.b. to 10.87% d.b. In conclusion, research on the sorption characteristics (equilibrium and monolayer moisture content) of mint powder of Bulgarian origin is conducted. It is noted the economic and commercial importance of Bulgarian crop and the necessity of more profound researches of the regional herb product. [ABSTRACT FROM AUTHOR]

Recovering waste from industrial food processes and developing new healthy foods as plant protein sources has been a major focus of scientific research and industrial innovation in food. Thus, the consumption of plant-based beverages from soy, oat, or almond has been promoted. In the case of almonds, the resulting solid bagasse has an interesting nutritional profile and its transformation into a powdered product could be a valuable option for the food industry. The main objective of this work was to determine the effect of hot air drying at 60 and 70 °C and freeze-drying on the physicochemical, water interaction, emulsifying and antioxidant properties of powdered almond bagasse. Furthermore, hot air-drying curves have been modelled and isotherms at 20 °C have been performed. The proximate composition of the powder revealed a protein content of 15% and a fat content of 25%, which makes it a remarkably different powder from those obtained from other vegetable residues such as fruits and vegetables. This composition was decisive in the effect of the drying method and drying temperature, and no significant differences were observed on the physico-chemical or antioxidant properties regardless of the drying method used. However, freeze-drying resulted in a powder with a more homogeneous particle size distribution and better oil-interaction properties, especially with higher emulsifying activity and stability. [ABSTRACT FROM AUTHOR]

Cavex CA37 is a dental material used for positive tooth impressions. After the mold is taken, it hardens through a fast‐chemical reaction with air, then becomes waste after usage. In this study, natural sepiolite and Cavex CA37 are mixed at certain ratios to obtain a composite SCX‐37 biosorbent that is used for the biosorption of UO22+${\rm{UO}}_2^{2 + }$ ions from a synthetic aqueous solution. Parameters affecting biosorption, such as solution pH, ambient temperature, contact time, and UO22+${\rm{UO}}_2^{2 + }$ ion concentration, are investigated. The biosorption of UO22+${\rm{UO}}_2^{2 + }$ ions on SCX‐37 reaches equilibrium in 120 min with 97.56% efficiency at 30 °C and pH 4. The isotherms (Langmuir, Freundlich, and D‐R) and thermodynamic values of the biosorption of UO22+${\rm{UO}}_2^{2 + }$ ions on the SCX‐37 biosorbent are calculated according to the obtained data. It is determined that there is a high correlation between experimental results and all three isotherm models. The adsorption capacity is found to be 41.39 mg g−1. The biosorption of UO22+${\rm{UO}}_2^{2 + }$ ions onto the SCX37 biosorbent is a chemisorption process with an adsorption energy of 40.50 kJ mol−1. [ABSTRACT FROM AUTHOR]

The objective of this study is to experimentally determine the sorption isotherms and thermodynamic properties of green mint after undergoing thermal and biochemical treatment. The method employed is the gravimetric method using saturated saline solutions at various temperatures. In order to model and predict the hygroscopic behavior during drying and storage, we have utilized developed mathematical models (such as the Langmuir, GAB, modified BET, Peleg models, etc.). The adjustment and optimization of these models will be conducted using statistical techniques to analyze the obtained data. The isosteric desorption heats of green mint will be calculated using the Clausius-Clapeyron equation. This study will provide an expression to predict the thermodynamic properties of green mint. [ABSTRACT FROM AUTHOR]

Heavy metal exposure from wastewater is an important environmental issue worldwide. In the search for more efficient treatment technologies, biosorption has been presented as an alternative for contaminant removal from wastewaters. The aim of this work is to determine the operation parameters of copper adsorption followed by biosorbent regeneration. The algae Durvillaea antarctica and Lessonia trabeculata were used as biosorbents in batch experiments. These biosorbents were exposed to different conditions, such as pH, copper concentration, exposure time, mass-to-volume ratios and regeneration reagents. Batch sorption tests revealed an adequate pH of 4.5–5.0. The selected biosorbent was D. antarctica due to a considerably higher copper retention capacity. As a regenerating reagent, sulfuric acid was more efficient. For diluted copper solutions (10 to 100 mg L−1), a biosorbent particle size of between 1.70 and 3.36 mm showed better retention capacity than larger particles and a biosorbent mass-to-volume ratio of 10 g L−1 was desirable for these metal concentrations. [ABSTRACT FROM AUTHOR]

Sustainable methods such as convective drying have regained interest in reducing the loss and waste of food produce. Combined with techniques like blanching and edible coatings, they could serve as useful tools in food processing development. Composite coatings comprising pectin, soy protein isolate, and xanthan gum were optimized using response surface methodology with the Box–Behnken design. This optimization aimed to investigate their effects on the moisture content, water activity, total color, and rehydration ratio of fresh and blanched chayote slices. Additionally, the study explored the modeling of the drying kinetics and sorption isotherms of chayote (Sechium edule) slices. Soy protein and xanthan gum were found to primarily influence the moisture content (ranging from 5.44% to 9.93%), and pectin influenced water activity (033 to 0.53) of the fresh-coated chayote, while pectin affected the aw (2.13–8.28) and rehydration of the blanch-coated chayote. The optimized formulations for both fresh and blanched chayote were utilized to assess the drying kinetics behavior and sorption isotherms. The best fit (R2: 0.996 to 0.999) was achieved with the parabolic model for thin-layer materials. Furthermore, the sorption isotherms of chayote displayed a Type IV behavior, with the BET model being the most suitable for describing the sorption behavior of materials with low water activity. The predicted values offer valuable data for optimizing processing conditions to enhance the quality and stability of dried chayote.

Agglomeration is a technological process that is widely applied to obtain powdered products with the appropriate shape and particle size and different physical characteristics and stabilities. The purpose of this research was to study the influences of the composition and storage of powdered infant formulas on their thermal behaviours, as analysed by differential scanning calorimetry (DSC); fatty acid compositions, as determined by gas chromatography; and water activity and water content. This study investigated the influence of the storage time (six months) at temperatures of 20–22 °C and air humidities of 42–45% on powder mixtures and agglomerates. The isotherms of the agglomerates presented a shape and course similar to those of the isotherms of the mixtures from which they were obtained. The agglomeration process affected the stability of the fatty acids in the stored powdered infant formulas. The composition of the fatty acids changed during the storage process. The thermal properties of the powdered infant formulas were not significantly influenced by agglomeration. The compositions of the mixtures and agglomerates influenced the shape and course of the DSC diagrams. Using the DSC method, it was determined whether the fat was a natural component of the powder or it was added in the form of fatty acid preparations. Differences were observed between the shape and course of the DSC curves (heating and cooling) obtained for fresh and 6-month-stored mixtures and agglomerates.