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Plants (Basel, Switzerland) Oct 2022Salt stress during pre-harvest limits the shelf life and post-harvest quality of produce; however, silicon nutrition can mitigate salt stress in plants. Thus, we...
Salt stress during pre-harvest limits the shelf life and post-harvest quality of produce; however, silicon nutrition can mitigate salt stress in plants. Thus, we evaluated the effects of salinity and fertilization with Si, in pre-harvest, on the morpho-physiological characteristics of onion bulbs during shelf life. The experiment was set up in randomized complete blocks, with treatments arranged in split-split plots. The plots had four levels of electrical conductivity of irrigation water (0.65, 1.7, 2.8, and 4.1 dS m). The subplots had five fertilization levels with Si (0, 41.6, 83.2, 124.8, and 166.4 kg ha). The sub-sub plots had four shelf times (0, 20, 40, and 60 days after harvest). Irrigation water salinity and shelf time reduced firmness and increased the mass loss of onion bulbs during shelf life. Salt stress reduced the contents of sugars and total soluble solids of onion bulbs during storage; however, Si supply improved the contents of these variables. Salinity, Si supply, and shelf time increased the concentrations of pyruvic and ascorbic acids in onion bulbs during shelf life. Si doses between 121.8 and 127.0 kg ha attenuated the impacts caused by moderate salinity, increasing the synthesis of metabolites and prolonging the onion bulbs' shelf life.
PubMed: 36297810
DOI: 10.3390/plants11202788 -
Materials (Basel, Switzerland) Oct 2022The development of geopolymer building composites at a lower cost with a smaller carbon footprint may lessen the growing concerns about global warming brought on by... (Review)
Review
The development of geopolymer building composites at a lower cost with a smaller carbon footprint may lessen the growing concerns about global warming brought on by emissions of a critical greenhouse gas (CO) paired with the high production costs in the cement sector. Diatomaceous earth, commonly used as an admixture or partial replacement of cement owing to its most effective pozzolanic properties, has been investigated as a precursor in geopolymer concrete development. Several studies have been examined to develop a greater understanding of its characterization, inclusion status, and impacts on the performance aspects of concrete. The literature review showed that using diatomaceous earth is one of the effective ways to create sustainable, insulating, lightweight building materials while minimizing the harmful economic and environmental effects of industrial solid wastes. However, since most studies have focused on its integration as a partial cement substitute or a replacement for fine aggregate, further research on diatomaceous earth-based clinker-free concrete is required. A lack of research on geopolymer concrete's reinforcement with either natural or synthetic fibers, or a combination of the two, was also discovered. This review also showed that there has been remarkably little effort made towards theoretical property correlation modeling for predicting concrete performance. It is anticipated that the detailed overview presented herein will guide potential researchers in defining their future paths in the study area.
PubMed: 36295195
DOI: 10.3390/ma15207130 -
Insects Sep 2022(Schrank) (Acari: Acaridae) is a cosmopolite mite species commonly in found food and stored products. In this study, the acaricidal activity of two Turkish diatomaceous...
(Schrank) (Acari: Acaridae) is a cosmopolite mite species commonly in found food and stored products. In this study, the acaricidal activity of two Turkish diatomaceous earth (DE) formulations (Detech WP95 and Detech Dust) were applied on a concrete surface at five different concentrations (1, 2.5, 5, 7.5, and 10 g/m) and dead individuals were counted at 11 different time intervals (1, 3, 6, 9, 12, 15, 18, 21, 24, 27, and 30 h) at a temperature of 25 ± 1 °C and 75 ± 5% relative humidity (RH). Mite mortalities were observed after 6- and 18-hour exposure periods at all concentrations of dust and wettable powder (WP) formulations, respectively. Specifically, 100% mortality for the WP formulation was achieved at the highest concentration of 10 g/m after 15 h of exposure and after 27 h and 30 h for the lowest concentration. In the case of dust formulation, mortalities were observed after 3 h of exposure at all concentrations except at 1 g/m, while a 100% mortality rate was achieved after 21 h of exposure to all concentrations and after 18 h of exposure for 7.5 g/m and 10 g/m. This study indicates that both WP and dust formulations of local diatomaceous earth can cause 100% mortality in 24 h on average and can be a promising alternative to conventional chemical acaricides.
PubMed: 36292805
DOI: 10.3390/insects13100857 -
Molecules (Basel, Switzerland) Sep 2022Residual diatomaceous earth (RDE) from winemaking activities is a rich and currently underexploited source of phenolic compounds which ought to be recycled from the...
Residual diatomaceous earth (RDE) from winemaking activities is a rich and currently underexploited source of phenolic compounds which ought to be recycled from the perspective of circular bioeconomy. In this work, we demonstrate the feasibility of molecularly imprinted polymers (MIPs) for the enrichment of quercetin, a flavonoid at a fairly high content in residual diatomaceous earth. These MIPs were synthesized through free radical polymerization. FTIR confirmed the integration of the functional monomers into the polymeric chains. Batch adsorption experiments were used to assess the retention and selectivity of those MIPs towards quercetin. Commercial resins were compared with the synthesized materials using the same procedures. These adsorption experiments allowed the selection of the best performing MIP for the valorization of RDE extract. This treatment consisted of saturating the selected MIP with the extract and then desorbing the retained compounds using solvents of selected compositions. The desorbed fractions were analyzed using liquid chromatography, and the results demonstrated an increase in quercetin's fractional area from 5% in the RDE extract to more than 40% in some fractions, which is roughly an eightfold enrichment of quercetin. Moreover, other flavonoids of close chemical structure to quercetin have been rather retained and enriched by the MIP.
Topics: Adsorption; Diatomaceous Earth; Flavonoids; Molecular Imprinting; Molecularly Imprinted Polymers; Plant Extracts; Quercetin; Solid Phase Extraction; Solvents
PubMed: 36234945
DOI: 10.3390/molecules27196406 -
Materials (Basel, Switzerland) Oct 2022The presented research is focused on the complex assessment of three different types of diatomaceous earth and evaluation of their ability for application as pozzolana...
The presented research is focused on the complex assessment of three different types of diatomaceous earth and evaluation of their ability for application as pozzolana active admixtures applicable in the concrete industry and the production of repair mortars applicable for historical masonry. The comprehensive experimental campaign comprised chemical, mineralogical, microstructural, and physical testing of raw materials, followed by the analyses and characterization of pozzolanic activity, rheology and heat evolution of fresh blended pastes, and testing of macrostructural and mechanical parameters of the hardened 28-days and 90-days samples. The obtained results gave evidence of the different behavior of researched diatomaceous earth when mixed with water and Portland cement. The differences in heat evolution, initial and final setting time, porosity, density, and mechanical parameters were identified based on chemical and phase composition, particle size, specific surface, and morphology of diatomaceous particles. Nevertheless, the researched mineral admixtures yielded a high strength activity index (92.9% to 113.6%), evinced their pozzolanic activity. Three fundamental factors were identified that affect diatomaceous earth's contribution to the mechanical strength of cement blends. These are the filler effect, the pertinent acceleration of OPC hydration, and the pozzolanic reaction of diatomite with Portland cement hydrates. The optimum replacement level of ordinary Portland cement by diatomaceous earth to give maximum long-term strength enhancement is about 10 wt.%., but it might be further enhanced based on the properties of pozzolan.
PubMed: 36234222
DOI: 10.3390/ma15196881 -
Materials (Basel, Switzerland) Sep 2022The poly(lactic acid) (PLA) biodegradable polymer, as well as natural, siliceous reinforcement in the form of diatomaceous earth, fit perfectly into the circular economy...
The poly(lactic acid) (PLA) biodegradable polymer, as well as natural, siliceous reinforcement in the form of diatomaceous earth, fit perfectly into the circular economy trend. In this study, various kinds of commercial PLA have been reinforced with diatomaceous earth (DE) to prepare biodegradable composites via the extrusion process. The structure of the manufactured composites as well as adhesion between the matrix and the filler were investigated using scanning electron microscopy (SEM). Differential scanning calorimetry (DSC) analyses were carried out to determine crystallinity of PLA matrix as function of DE additions. Additionally, the effect of the ceramic-based reinforcement on the mechanical properties (Young's modulus, elongation to failure, ultimate tensile strength) of PLA has been investigated. The results are discussed in terms of possible applications of PLA + DE composites.
PubMed: 36143522
DOI: 10.3390/ma15186210 -
Chemosphere Dec 2022The progress of engineering technologies highly influences the development of methods that lead to the condition improvement of areas contaminated with heavy metals...
The progress of engineering technologies highly influences the development of methods that lead to the condition improvement of areas contaminated with heavy metals (HMs). The aided phytostabilization fits into this trend, and was used to evaluate HM-immobilization effectiveness in phytostabilized soils under variable temperatures by applying 16 freezing-thawing cycles (FTC). Diatomite amendment and Lolium perenne L., also were applied. Cd/Ni/Cu/Pb/Zn each total content in phytostabilized soils were determined, along with the verification for each metal of its distribution in four extracted fractions (F1 ÷ F4) from soils. Based on changes in HM distribution, each metal's stability was estimated. Moreover, HM accumulation in plant roots and stems and soil microbial composition were investigated. Independently of the experimental variant (no-FTC-exposure or FTC-exposure), the above-ground biomass yields in the diatomite-amended series were higher as compared to the corresponding control series. The evident changes in Pb/Zn-bioavailability were observed. The metal stability increase was mainly attributed to metal concentration decreasing in the F1 fraction and increasing in the F4 fraction, respectively. Diatomite increased Cd/Zn-stability in not-FTC-exposed-phytostabilized soils. FTC-exposure favorably influenced Pb/Zn stability. Diatomite increased soil pH values and Cd/Ni/Cu/Zn-bioaccumulation (except Pb) in roots than in stems (in both experimental variants). FTC-exposure influenced soil microbial composition, increasing bacteria abundance belonging to Actinobacteria, Gammaproteobacteria, and Sphingobacteria. At the genus level, FTC exposure significantly increased the abundances of Limnobacter sp., Tetrasphaera sp., Flavobacterium sp., and Dyella sp. Independently of the experimental variant, Sphingomonas sp. and Mycobacterium sp., which have a tolerance to HM contamination, were core bacterial groups, comprising about 6 ÷ 7% of all soil bacteria.
Topics: Cadmium; Diatomaceous Earth; Lead; Metals, Heavy; Microbiota; Soil; Soil Pollutants
PubMed: 36088975
DOI: 10.1016/j.chemosphere.2022.136332 -
International Journal of Molecular... Aug 2022A neoteric round sieve diatomite (De) decorated with sea-urchin-like alpha-type iron trioxide (α-FeO) synthetics was prepared by the hydrothermal method and further...
A neoteric round sieve diatomite (De) decorated with sea-urchin-like alpha-type iron trioxide (α-FeO) synthetics was prepared by the hydrothermal method and further calcination. The results of the electromagnetic (EM) parameters of α-FeO-decorated De (α-FeO@D) showed that the minimum reflection loss (RL) of α-FeO@D could reach -54.2 dB at 11.52 GHz and the matched absorber thickness was 3 mm. The frequency bandwidth corresponding to the microwave RL value below -20 dB was up to 8.24 GHz (9.76-18 GHz). This indicates that α-FeO@D composite can be a lightweight and stable material; because of the low density of De (1.9-2.3 g/cm), the density of α-FeO@D composite material is lower than that of α-FeO (5.18 g/cm). We found that the combination of the magnetic loss of sea-urchin-like α-FeO and the dielectric loss of De has the most dominant role in electromagnetic wave absorption and loss. We focused on comparing the absorbing properties before and after the formation of sea-urchin-like α-FeO and explain in detail the effects of the structure and crystal shape of this novel composite on the absorbing properties.
Topics: Diatomaceous Earth; Microwaves
PubMed: 36012621
DOI: 10.3390/ijms23169362 -
Cells Aug 2022This paper analyses the impact of the diatomaceous earth/peat (DEP; 3:1) microbial carrier on changes in the bacterial microbiome and the development of biofilm in the...
This paper analyses the impact of the diatomaceous earth/peat (DEP; 3:1) microbial carrier on changes in the bacterial microbiome and the development of biofilm in the anaerobic digestion (AD) of confectionery waste, combined with digested sewage sludge as inoculum. The physicochemical properties of the carrier material are presented, with particular focus on its morphological and dispersion characteristics, as well as adsorption and thermal properties. In this respect, the DEP system was found to be a suitable carrier for both mesophilic and thermophilic AD. The evaluation of quantitative and qualitative changes in the genetic diversity of bacterial communities, carried out using next-generation sequencing (NGS), showed that the material has a modifying effect on the bacterial microbiome. While Actinobacteria was the most abundant cluster in the WF-control sample (WF-waste wafers), Firmicutes was the dominant cluster in the digested samples without the carrier (WF-dig.; dig.-digested) and with the carrier (WF + DEP). The same was true for the count of Proteobacteria, which decreased twofold during biodegradation in favor of Synergistetes. The cluster was identified as the most abundant genus in the two samples, particularly in WF + DEP. This information was supplemented by observations of morphological features of microorganisms carried out using fluorescence microscopy. The biodegradation process itself had a significant impact on changes in the microbiome of samples taken from anaerobic bioreactors, reducing its biodiversity. As demonstrated by the results of this innovative method, namely the BioFlux microfluidic flow system, the decrease in the number of taxa in the digested samples and the addition of DEP contributed to the microbial adhesion in the microfluidic system and the formation of a stable biofilm.
Topics: Anaerobiosis; Bacteria; Bioreactors; Diatomaceous Earth; Genetic Variation; Sewage; Soil
PubMed: 36010646
DOI: 10.3390/cells11162571 -
Polymers Aug 2022Amorphous diatomite was used as a filler for a thermoplastic polymer of polyamide 11 obtained from natural sources. The diatomite particles of different sizes were...
Amorphous diatomite was used as a filler for a thermoplastic polymer of polyamide 11 obtained from natural sources. The diatomite particles of different sizes were previously fractionated by sedimentation to obtain powders with varying particle size distribution, including powders with or without frustule particles, crushed, uncrushed or agglomerated. Biocomposites containing 2.5, 5, 10 and 20% filler were tested for their mechanical properties, including tensile strength, flexural strength and impact strength. In addition, a particle size analysis (by Dynamic Light Scattering, DLS) was performed and the dispersion of the filler in the polymer matrix (Scanning Electron Microscopy, SEM), thermal parameters (Differential Scanning Calorimetry, DSC, and Dynamic Mechanical Analysis, DMA) were determined. Testing showed that biocomposites modified with diatomaceous earth have a higher mechanical strength than the reference system, especially with larger amounts of the filler (10 and 20%), e.g., the tensile strength of pure PA11 is about 46 MPa, while 20OB and 20OF 47.5 and 47 MPa, respectively, while an increase in max. flexural strength and flexural modulus is also observed compared to pure PA11 by a maximum of 63 and 54%, respectively Diatomaceous earth can be obtained in various ways-it is commercially available or it is possible to breed diatoms in laboratory conditions, while the use of commercially available diatomite, which contains diatoms of different sizes, eliminates the possibility of controlling mechanical parameters by filling biocomposites with a filler with the desired particle size distribution, and diatom breeding is not possible on an industrial scale. Our proposed biocomposite based on fractionated diatomaceous earth using a sedimentation process addresses the current need to produce biocomposite materials from natural sources, and moreover, the nature of the process, due to its simplicity, can be successfully used on an industrial scale.
PubMed: 35956665
DOI: 10.3390/polym14153153