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Porous particles composed of 2,2,6,6-tetramethylpiperidinyl-1-oxyl-oxidized cellulose nanofiber (TOCN) as building block, i.e., porous TOCN particles, are attracting attention due to their environmental friendliness, superior properties, such as easy handling, large surface area, and high adsorption capacity. However, the instability of TOCNs in aqueous environments limits their applications. An effective solution to improve water resistance of TOCN particles is to reduce the hydrophilicity of TOCNs by forming chemical bonds with a cross-linker. In this study, Carbodilite, a common, easy-to-use, commercially available cross-linker with carbodiimide groups, was used to investigate a chemical cross-linking strategy for porous TOCN particles prepared by spray drying. The water resistance of cross-linked TOCN particles was evaluated through morphological observation by SEM images. The presence of polycarbodiimide significantly increased water resistance of cross-linked TOCN particles up to 24 h. This study demonstrates the trade-off between water resistance and adsorption efficiency according to cross-linker concentrations. These data are useful for interface science of TOCNs in liquids, assisting in controlling specific properties of porous TOCN particles for particular applications in adsorption and separation.

This work is aimed to study the effects of component size and solubility on the surface composition of spray dried (SD) uniform two-component particles fabricated by micro-fluidic spray dryer. Various precursor liquid consisting of small molecular of methionine (Met, 33 g/L) or lysine (Lys, 739 g/L) and large-sized silica (12 nm) were prepared by adjusting the mass ratio of components. X-ray energy dispersive results showed that the respective enrichment degree (De) of Met and Lys on the surface of SD-M1S9 and -L1S9 prepared at 150 °C were 182 ± 9% and 125 ± 14%. The De of hydrophobic Met for SD-M1S1 and -M9S1 were 46 ± 9% and 4 ± 2%, respectively, whereas relative hydrophilic Lys mainly distributed internal of the particle meanwhile the De of silica on the surface for SD-L1S1 and -L9S1 were 17 ± 4% and 12 ± 1%, respectively. Drying temperature (120 and 180 °C) showed more apparent effect on the De of amino acid for the particles of less amino acid. The possible formation mechanism of surface composition and the surface composition impact on the wettability of particles were explored. These results provide new guidance for manufacturing functional SD powders with various components.

Despite increasing interest in using nanofibrillated cellulose (NFC) as food thickener and emulsifier, poor water redispersibility of dried NFC, which is form suitable for practical utilization, significantly limits such applications. Studies are lacking on preparation of dried NFC with superior redispersibility. The present study therefore proposed and examined strategies to improve water redispersibility of spray dried NFC via the use of selected co-carriers, i.e., gum Arabic with/without xanthan gum, carboxymethyl cellulose or pectin. Synergistic interactions between NFC and co-carriers, as confirmed by X-ray diffraction (XRD) patterns and Fourier transform infrared (FTIR) spectra, helped prevent NFC agglomeration during spray drying. All reconstituted spray-dried NFC/co-carriers suspensions exhibited shear-thinning and gel-like behaviors, thus supporting the use of such suspensions as thickener and emulsifier. Spray-dried NFC with 80% gum Arabic and 20% xanthan gum (SD-NFC/GA20XG) resulted in suspension with highest viscosity; the suspension also performed best at recovering viscous characteristics of NFC. Water thickened by SD-NFC/GA20XG had strongest shear-thinning behavior, indicating that SD-NFC/GA20XG suspension resulted in smoothest mouth feel and easiest swallowing. Such observations were supported by XRD patterns of SD-NFC/GA20XG, which suggested that its relative crystallinity was the lowest. Its FTIR spectra also showed the highest intensity of -OH bending and carbonyl bands, which are directly related to water adsorption capability of NFC. Use of reconstituted SD-NFC/GA20XG as emulsifier also resulted in highest stability for oil-in-water (O/W) Pickering emulsion during storage for up to 30 days.

A spray-drying assisted solid-state method to prepare spherical layer-structured H2TiO3 ion sieve (LSTIS) particles is reported herein. The effects of synthesis parameters (calcination temperature, calcination time, and the lithium-titanium molar ratio) on adsorption–desorption performance (the delithiation ratio, titanium dissolution loss, and the adsorption capacity) were investigated. The as-prepared LSTIS exhibited an equilibrium adsorption capacity of 30.08 mg·g–1 (average of 25.85 mg·g–1 over 5 cycles) and ultra-low titanium dissolution loss of less than 0.12% (average of 0.086% over 5 cycles). The LSTIS showed excellent selectivity toward Li+ in Na+, K+, Mg2+, and Ca2+ coexisting saline solutions where its adsorption capacity reached 27.45 mg·g–1 and the separation factors of Li+ over the coexisting cations exceeded 100. The data suggests that the LSTIS is promising to competitively enrich Li+ from saline solutions.

In this study we synthesized Li-rich Li1.2Ni0.13Mn0.54Co0.13O2 (LMNCO) as a composite cathode material through a two-step spray-drying method, using transition metal (TM) acetates and citric acid (CA, as a chelating agent) at various molar ratios and then calcining at various temperatures for various periods of time. This two-step spray-drying method created hierarchical nano/micro-sphere structures of the LMNCO cathode material. The LMNCO cathode exhibited the best electrochemical performance when synthesized with a TM:CA ratio of 3:2, a calcination temperature of 900 °C, and a calcination time of 5 h. This as-prepared LMNCO composite was then modified with polyimide (PI) at various weight ratios (PI/LMNCO = 0.5, 1.0, and 1.5 wt%) to improve its electrochemical properties. Among the various structures, the LMNCO cathode material coated with 1.0 wt% of PI at a layer thickness of approximately 1.88 nm achieved the best initial discharge capacities. This modified electrode also displayed enhanced cycle stability, with over 93.3 and 87.9% of the capacity retained after 30 cycles at 0.1C and 100 cycles at 1C, respectively. In comparison, the capacity retention of the unmodified LMNCO electrode measured under the same conditions was no more than 91.3% at 0.1C and 70.1% at 1C. Thus, surface modification with PI was an effective method for improving the coulombic efficiency, discharge capacity, and long-term cycling performance of the LMNCO cathode. Such PI-coated LMNCO composite cathode materials appear to be potential candidates for use in next-generation high-performance lithium-ion batteries.

In this work, a hierarchical reduced graphene oxide (RGO) supportive matrix consisting of both larger two-dimensional RGO sheets and smaller three-dimensional RGO spheres was engineered with ZnO and SnO2 nanoparticles immobilized. The ZnO and SnO2 nanocrystals with controlled size were in sequence engineered on the surface of the RGO sheets during the deoxygenation of graphene oxide sample (GO), where the zinc-containing ZIF-8 sample and metal tin foil were used as precursors for ZnO and SnO2, respectively. After a spray drying treatment and calcination, the final ZnO@SnO2/RGO-H sample was obtained, which delivered an outstanding specific capacity of 982 mAh·g-1 under a high current density of 1000 mA·g-1 after 450 cycles. Benefitting from the unique hierarchical structure, the mechanical strength, ionic and electric conductivities of the ZnO@SnO2/RGO-H sample have been simultaneously promoted. The joint contributions from pseudocapacitive and battery behaviors in lithium-ion storage processes bring in both large specific capacity and good rate capability. The industrially mature spray drying method for synthesizing RGO based hierarchical products can be further developed for wider applications.

Zirconium carbide hollow microspheres (ZrC HMs) were fabricated via spray drying process and polymer-derived ceramics technique. The stable and homogeneous ZrC precursor solution can be prepared by mixing polyzirconoxane (PZO), phenolic resin (PR), curing agent p-toluenesulfonic acid (TsOH) and solvent n-propanol. The precursor solution was spray-dried to form hollow precursor microspheres. During the spray drying process, morphology of the hollow precursor microspheres can be regulated by adjusting temperature of inlet hot N2, concentration of precursor solution and the amount of curing agent TsOH. The prepared hollow precursor microspheres were carbonized at 700 °C and then converted into ZrC HMs by carbothermal reduction reaction above 1500 °C. During the pyrolysis process, nanosized ZrO2 grains produced by PZO decomposition are evenly dispersed, so is the carbon produced by PR pyrolysis, as prevents overgrowth of ZrO2 grains in the following process, even when it is changed to ZrC. ZrC HMs maintained excellent spherical morphology at temperatures of 1500–1900 °C, with particle size Dv(50)=16.4–18.7 μm, which enable their promising applications in ultra-high temperature insulation material. This preparation method is simple and can be prepared on a large scale.

This paper proposes a comparative study of two techniques of granulation of a submicronic alumina powder with high binder content slurries, by spray drying and freeze granulation for the preparation of mixed granules. First, the viscosity and flow index of the suspensions are given as a function of dispersant, solid and binder contents versus alumina content, and the data are analysed in order to give a predictive model in a wide range. Suspensions with varying viscosities (7–208 mPa.s), densities (1.31–1.76) and surface tensions (23–40 mN/m) were then granulated. The first observations reveal the importance of the content and the molar mass of the binder: when they are too high, the freeze granulation fails and filaments are produced instead of granules due to extensive stretching of the molecular chains of the binder during spraying. Then through a theoretical analysis of the phenomena leading to granulation, an original dimensionless number is proposed to describe the evolution of the granule size as a function of suspension formulation. This number is related to the Reynolds and Weber number and is able to predict the granule size over a wide range (20–500 μm for freeze granulation, and 5–30 μm for spray drying). Spray drying leads to smaller granules with various shapes, from full shape to hollow or donut-like, whereas freeze granulation leads to bigger but spherical granules with a microporosity, and a size easier to predict as no drying shrinkage is observed.

Multifunctional fillers are greatly required for dental resin composites (DRCs). In this work, a spray dryer with a three-fluid nozzle was applied for the first time to construct high-performance complex nanoparticle clusters (CNCs) consisting of different functional nanofillers for dental restoration. The application of a three-fluid nozzle can effectively avoid the aggregation of different nanoparticles with opposite zeta potentials before the spray drying process in order to construct regularly shaped CNCs. For a SiO2–ZrO2 binary system, the SiO2–ZrO2 CNCs constructed using a three-fluid nozzle maintained their excellent mechanical properties ((133.3 ± 4.7) MPa, (8.8 ± 0.5) GPa, (371.1 ± 13.3) MPa, and (64.5 ± 0.7) HV for flexural strength, flexural modulus, compressive strength, and hardness of DRCs, respectively), despite the introduction of ZrO2 nanoparticles, whereas their counterparts constructed using a two-fluid nozzle showed significantly decreased mechanical properties. Furthermore, heat treatment of the SiO2–ZrO2 CNCs significantly improved the mechanical properties and radiopacity of the DRCs. The DRCs containing over 10% mass fraction ZrO2 nanoparticles can meet the requirement for radiopaque fillers. More importantly, this method can be expanded to ternary or quaternary systems. DRCs filled with SiO2–ZrO2–ZnO CNCs with a ratio of 56:10:4 displayed high antibacterial activity (antibacterial ratio > 99%) in addition to excellent mechanical properties and radiopacity. Thus, the three-fluid nozzle spray drying technique holds great potential for the efficient construction of multifunctional cluster fillers for DRCs.

The surfactants used for emulsion is one of the best techniques for microencapsulation of lactic acid bacteria (LAB) since it is economical. The biosurfactants have many advantages such as lower toxicity, higher biodegradability. In this study, microcapsules were prepared via spray drying using Bifidobacterium adolescentis species cultured in soy milk extract with biosurfactant prepared using Alcaligenes piechaudii CC-ESB2 to improve their powder properties. The soy milk was used to increase the health benefits instead of the milk. The optimum bacterial strain viability, water activity, and moisture content of the microcapsules were achieved at a spray dryer inlet/outlet temperature of 120/60°C. The composition of the carrier affects the particle size of the microcapsules. Using 90% maltodextrin (MD), 5% isomalto-oligosaccharide syrup (IMOS) and 5% biosurfactant as a carrier increased the viability of the LAB. Scanning electron microscope observations showed that the LAB microcapsules were able to effectively retain their completeness. Furthermore, microcapsules added with a biosurfactant prepared using A. piechaudii CC-ESB2 displayed significantly better flow properties than those without the surfactant and biosurfactant, which indicates that the biosurfactant assists in enhancing the powder properties of the microcapsules. It also has sufficient biological activity as a LAB product because the probiotics exceed 10

The Wastewater Evaporation System (WES) was a reliable and economical way to treat desulfurization wastewater. However, the evaporation mechanism was not clear, and the evaporation product properties were lack of awareness. In this study, the evaporation and product properties were revealed by the single droplet drying (SDD) method and spray drying system. It was found that the evaporation process of wastewater involved the constant rate and falling rate period. The component of the evaporation product from the SDD and spray drying method were similar, mainly consisted of MgCl2, CaCl2, NaCl and CaSO4. Besides, the potential risks of WES were assessed. After wastewater evaporation, the Electrostatic Precipitator (ESP) removal efficiency was enhanced due to the aggregation of fine particles and the enhanced specific resistance. For the influence of WES on comprehensive fly ash utilization, the chloride mass fraction in the final product was lower than 0.06% and could meet strict regulations.

Phenolic compounds constitute important parts of natural bioactive ingredients due to their various biological activities. However, phenolic compounds are to some extent restricted by low solubility, poor stability, unpleasant taste and low bioavailability. Spray-drying microencapsulation is an effective strategy to ameliorate or even tackle such problems and it is crucial to choose optimal wall materials which may affect functional properties of the encapsulated components. In this review, we first described and discussed the physicochemical characteristics of commonly used wall materials for spray drying. Then we summarized the work done in past 16 years about the microencapsulation of phenolic compounds including anthocyanidin, curcumin, catechins, gallic acid, and resveratrol using spray drying is reviewed with a focus on the role of wall materials. Furthermore, we propose some targeted encapsulation strategies for different bioactive ingredients to explore their applications. Finally, we intend to encourage more research in rational selection of the wall materials.

Spray-dried products, such as synthetic peptides and hormones, have already been approved by the U.S. Food and Drug Agency and the European Medicines Agency, while spray-dried antibodies or interleukins, are not yet available on the market. Concerning the latter group, knowledge on whether and how spray-drying (SD) can be performed without adversely affecting their biological activity is lacking. Accordingly, this study aimed at establishing a SD process (Buchi B-90 spray dryer) using three Interleukin-8 based proteins (7–74 kDa) that were dispersed in phosphate buffered saline to maintain their stability. A Box-Behnken Design of Experiments was conducted to identify the appropriate process parameters taking into account the thermal stability of interleukin-8. In parallel, a FD process was developed. Both powders were stored for up to 12 weeks. Powder characterization included residual moisture evaluation and the mean particle size of the SD powder was investigated with Laser Diffraction Analysis. The hydrodynamic volume was measured via size exclusion chromatography and sodium dodecyl sulfate–polyacrylamide gel electrophoresis. The secondary structure of the model proteins in the solid state was assessed with Fourier-transformation infrared spectroscopy for detecting the protein folding patterns and reconstituted with Circular Dichroism Spectroscopy. Finally, the binding affinity was studied with Surface Plasmon Resonance and Isothermal Fluorescence Titration, the protein stability with Chaotropic Unfolding, and the activity studies were carried out with the chemotaxis assay. The results showed that SD and FD powders with a residual moisture of less than 5 wt% were obtained. The interleukins showed no unfolding upon processing, neither in solid state nor reconstituted. Oligomerization was observed for FD, but not for SD interleukins. However, the unfolding, binding affinity and activity of all interleukins examined did not decrease in neither SD nor FD powders, even after 12 weeks of storage. Thus, it can be concluded that SD of interleukin formulations at outlet temperatures close to ambient temperature is a promising process for transferring them into a stable powder.

5 Figuras.-- 8 Tablas, A factorial design was performed for the microencapsulation of chia oil by spray drying at pilot-scale, to validate the results obtained previously at laboratory scale in a Büchi-B290. The effects of drying-air inlet (Tinlet) and outlet (Toutlet) temperatures in a Niro Production Minor on the solid yield, thermal efficiency, theoretical droplet evaporation times, and physico-chemical properties of powders were analyzed. The theoretical droplet evaporation times (0.31−0.54 s) were calculated considering the constant and falling rate periods and a negligible relative velocity between spray and air. Critical diameters between 31.77–41.57 μm were estimated for microcapsules, depending on the process conditions. After scale-up of the spray drying operation, higher solid yields (74.24–79.79%), thermal efficiencies (27.56–73.19%), encapsulation efficiencies (96.97–98.57%), and enhanced flowability of products, compared with experiments at laboratory scale, were observed. Moreover, the scale-up did not affect the chemical composition of microencapsulated oils, their fatty acid composition before and after in-vitro digestion processes. A global optimization was performed at pilot-scale and the process conditions that simultaneously optimized all the responses was 160 °C × 90 °C (Tinlet × Toutlet)., This research was financed with grants from Consejo de Investigaciones Científicas y Técnicas (CONICET), Argentina. The authors would like to acknowledge the Iberoamerican Project CYTED 119RT0567. María Gabriela Bordón would like to acknowledge the fellowships from CONICET and from Secretaría General Iberoamericana-Fundación Carolina.

Spray and freeze drying practices for production of the probiotic Bacillus amyloliquefaciens H57 as a power for feed applications were investigated. The importance of inlet temperature, feed rate, solid content, and limestone, a heating protectant, concentration was demonstrated. Spray drying outlet temperature appeared to be crucial for survivability of B. amyloliquefaciens H57. Studying inactivation kinetics at 80, 90, and 100 °C revealed the highest D-value at 260.7 ± 47.3 min at 80 °C before gradually declining with increasing temperature. By considering the D-value, a high survival rate of 100%, which was far superior to freeze drying at 60 ± 4%, was obtained when the spray drying outlet temperature was maintained at 80 °C with 175 ± 2 °C inlet temperature, 20.9 ± 0.4 mL min−1 feed rate, 20% solid content, and 1:0.3 ratio of dry mass of the probiotic material to limestone. After 50-days of storage, significant differences in the viability of B. amyloliquefaciens H57 were observed between the powders obtained by the two drying methods. Storage temperature had a substantial impact on the probiotic stability. Best viability retention was spray dried powder stored at 4 °C. This work demonstrates that spray drying can be an effective method for producing a functional probiotic and highlights its potential for applications in feed supplement manufacturing.