Diatomaceous Research Articles

Optimising Shielding Capacity: Pressure Effects on Diatomaceous Earth Composite Materials mixed with Sodium Silicate

Optimising Shielding Capacity: Pressure Effects on Diatomaceous Earth Composite Materials mixed with Sodium Silicate

Stability performance of an Algerian Ni/purified diatomite catalyst in the dry reforming methane reaction: characterization and properties

AbstractThis work aims to characterize and study the properties of an Algerian diatomaceous earth (Sig-Mascara) as a catalyst carrier. A commercial product of diatomite was characterized by granulometric analysis, X-ray fluorescence, X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis/differential scanning calorimetry and scanning electron microscopy/energy-dispersive X-ray spectroscopy methods. To purify the diatomite and remove the impurities (iron oxides, clay minerals, quartz and organic matters), the <63 μm fraction of the diatomite was separated out. The 15Ni/Ds-700 catalyst has lower SiO2, Al2O3 and CaO contents compared with the original diatomite. The NiO content of the catalyst is 15 wt.%, indicating successful impregnation. According to the nitrogen sorption–desorption results, the specific surface area of the purified diatomite particles (<63 μm) increased from 26.47 to 46.33 m2 g–1 compared to crude diatomite. The 15Ni/Ds-700 catalyst was applied in the dry reforming of methane to obtain synthesis gas (CO and H2). The results showed that the catalyst was relatively stable during catalytic measurements for 6 h, although the conversion rate value was low (12%).

Environmental assessment of alkali-activated materials based on agro-industrial waste as alkaline activators through leaching tests

Global circular economy drives the development of sustainable alkali activated materials (AAM) for use as construction material from industrial by-products and wastes. The assessment of the potentially hazardous substances release of these new material combinations into the soil and groundwater over time is essential. In this study, the aim is the environmental assessment of three AAMs based on blast furnace slag (BFS), activated with almond shell biomass ash (ABA) as potassium source and three solid sources of silica from the agricultural industry, rice husk ash (RHA), spent diatomaceous earth (SDE) and bamboo leaf ash (BLA), using European horizontal leaching tests proposed for construction materials, for monolithic form, Dynamic Surface Leaching Test (DSLT) and for granular form, Up-flow Percolation Test and the Compliance leaching test, by simulating different scenarios of their entire life cycle. The leaching results of the AAM showed the effectiveness of the inertization of all the recycled materials studied, which exceeded some inert materials limits, by means of the activation process. Despite the absence of significant differences in the leaching mechanisms of the oxyanions As, Cr, Mo, Sb, Se and V between the three AAMs developed, they presented different long-term leaching behavior depending on their form, monolithic, or granular, and therefore in their different life cycle stages. Therefore, it is concluded that although the incorporation of agro-industrial waste as alternative activators in BFS based AAM according to the Dutch Soil Quality Decree (for unrestricted use of monolithic and granular materials) is an environmentally acceptable option, the design of waste derived AAMs should be assessed by means of a combination of leaching tests that cover their expected life cycle.

Effect of Different Fertilizer and Silicon Levels on Grain Quality of Maize (Zea mays L.)

A field experiment with spilt plot design was conducted to study the ‘effect of fertility and silicon levels on the nutritional quality of maize’ during Kharif 2022 and 2023 at Rajasthan College of Agriculture (RCA), MPUAT, Udaipur, Rajasthan, India. The main plot treatments consist of four levels of Compounded NPK fertilizer (F0: Control, F50: 50% RDF, F75: 75% RDF and F100: 100 % RDF) and the sub-plot treatments consist of four levels of soil application of Diatomaceous Earth (Si0, Si100, Si200 and Si300). Pratap Makka-9 of maize variety was used for research purpose. The protein content, protein yield, carbohydrate and energy in maize grain were higher under 100% RDF than other levels of fertilizer. Application of 300 kg Diatomaceous Earth per hectare recorded higher protein content, protein yield, carbohydrate and energy in maize grain over the rest of silicon levels. The crude fat in maize grain was lower in 100% RDF. Application of 300 kg Diatomaceous Earth per hectare recorded lower crude fat in maize grain. Significantly higher protein yield was recorded under the combined application of 100% RDF and 300 kg diatomaceous earth per hectare. However, protein yield was at par in the application of 75% RDF with 300 kg Diatomaceous Earth per hectare and 100% RDF with 200 kg Diatomaceous Earth per hectare. The lowest crude fat was recorded under the combined application of 100% RDF and 300 kg Diatomaceous Earth per hectare over the rest of treatment combinations. Application of 100% RDF with 300 kg DE ha-1 (F100Si300) was recommended treatment for nutritional high quality maize grain.

Impact of diatomit on the transport behavior of unmodified and carboxyl-modified nanoplastics in saturated porous media

Due to the extensive use of plastic products and unreasonable disposal, nanoplastics contamination has become one of the important environmental problems that mankind must face. The composition and structure of porous media can determine the complexity and diversity of the transport behavior of nanoplastics. In this study, the influence of diatomite (DIA) on the nanoplastics transport in porous media is investigated by column experiments combined with XDLVO interaction energy and transport model. Results suggest that the recovery rates of unmodified polystyrene nanoparticles (PSNPs) and carboxyl-modified polystyrene nanoparticles (PSNPs-COOH) in the porous media containing DIA decreases compared with that in the pure quartz sand (QS), and the BTCs showed a “blocking” pattern. The presence of DIA inhibits the transport of both PSNPs and PSNPs-COOH, but the inhibition is not significant. This may be because the presence of DIA provides more favorable deposition sites for PSNPs and PSNPs-COOH to some extent. However, since DIA itself carries a certain negative charge, this can only play a role in compressing the double electric layer for PSNPs and PSNPs-COOH with the same negative charge, and cannot destabilize them. The migration capacity of PSNPs and PSNPs-COOH is strongest in the DIA-QS porous media at pH = 7, and is weak at pH = 9 and pH = 5. The inhibition of migration at pH = 9 can be attributed to the dissolution of the DIA surface under alkaline conditions and the formation of pore and defect structures, which provide more deposition sites for PSNPs and PSNPs-COOH. The presence of humic acid (HA) leads to an increase in the mobility of PSNPs and PSNPs-COOH, and the mobility is enhanced with HA concentration. The mobility of PSNPs and PSNPs-COOH in DIA-QS decreases with ionic valence and ionic strength, and PSNPs-COOH is more significantly inhibited compared to PSNPs.

Evaluation of potential adsorbents for simultaneous adsorption of phosphate and ammonium at low concentrations

Evaluation of potential adsorbents to tackle eutrophication caused by low concentrations of phosphate and ammonium are rarely reported in the literature. Besides, the dynamics/mechanisms for removal of these pollutants at low concentration are yet to be explored. In this study we used five different adsorbents, including La-modified zeolite (LMZ), MgFe-modified biochar (MgFe-BC), phoslock, activated alumina (AA), and diatomaceous earth (DE) to evaluate the removal of these pollutants. Among the selected adsorbents in this study, LMZ and AA both exhibited effective and simultaneous adsorption for phosphate and ammonium and the maximum adsorption capacities were 2.47 mg/g and 3.07 mg/g, respectively. The presence of SO42− and CO32− negatively impacted phosphate adsorption, while Fe3+ and K+ ions inhibited ammonium adsorption. LMZ adsorption kinetics was over 3 times faster than other adsorbents within 60 min reaction time. Kinetics studies and isotherms revealed that the removal of phosphate and ammonium was primarily driven by chemical interactions and monolayer adsorption and were better fitted by Langmuir isotherm than the Freundlich isotherm and kinetic study was effectively described by Pseudo-second-order kinetic model. FTIR and XPS analysis revealed that the key mechanisms for phosphate adsorption were electrostatic attraction and inner sphere complexation through ligand exchange, whereas ammonium adsorption was mainly governed by ion exchange. Desorption study revealed that LMZ material was stable after three desorption cycles. This study offers vital knowledge on the nature of adsorption and interactions of potential mesoporous adsorbents with eutrophication-causing pollutants in lakes and rivers and proposes effective remedial mean.

Cold sintering of complex-shaped ceramic materials

The present work explores for the first time the production of ceramic bodies with complex shape through the cold sintering process. Inspired by previous works on spark plasma sintering, a spacer accessory was designed to act as a removable mold. This proof-of-concept was tested with four different ceramic systems: biogenic hydroxyapatite, zinc oxide, diatomaceous earth and construction/demolition waste materials. In all cases, the density is comparable to that obtained by cold sintering of simpler disks. Moreover, the microstructure of the complex-shaped materials is substantially homogeneous in the entire component. Some distortions can be detected when comparing the spacer and sample shape, their control and modeling being a key challenge for future works.

Geology, mineralogy, geochemistry and genesis of volcano-sedimentary hosted Lake Abiyata diatomite in central main Ethiopian Rift

The Abiyata Diatomite deposit is located in the Main Ethiopian Rift, which is characterized by strong extensional tectonics. The deposit is mostly made up of diatomaceous earth, which is a sedimentary rock made up of the fossilized remnants of diatoms, which are tiny algae. Diatomite's geological, geochemical, and mineralogical features, as well as its formation, are discussed in this research. To characterize diatomite from Abiyata, chemical, mineralogical, technological, and micro paleontological examinations were conducted on samples collected from outcrops and stream sections. The XRD characteristic peaks of diatomite demonstrate that it is primarily made up of Opal A silica, however certain crystalline phases were discovered in adequate amounts. Quartz and feldspar were the predominant crystalline phases, with lesser amounts of Calcite, Cristobalite, Illite, Mordinite, Wairakite, Halloysite, Clinoaptilolite, Adularia, and Tridymite. From SEM photomicrographs diatomites are primarily formed of benthic freshwater diatom species such as Staurosirella pinnata, Staurosira construens, Pseudostaurosira brevistriata, Epithemia Sorex and surirella pinnata. Diatom species, sedimentary profile sections and mineralogical data suggest that diatomite was deposited in lacustrine-type freshwater shallow lake environment. Chemical data obtained from 10 diatomite samples show that while silica is the bodybuilding material for diatomite. i.e., Silica (SiO2), 76.9 %; Alumina (Al2O3), 3.49 %; Sodium Oxide (Na2O), 1.52 %; Potassium Oxide (K2O), 1.107 %; Iron Oxide (Fe2O3), 1.1 %; Loss on ignition (LOI) 13.7 and other oxides are below 1 %. Studies from technological properties like physical tests, chemistry, and mineralogy and micropaleontology of Abiyata diatomite suggest that calcined diatomite can be used for waste treatment processes in the filter aid industry and as filler material.

Toxicity of rock dust and charcoal powder enhanced with diatomaceous earth against rice weevil in maize stored by smallholder farmers

Toxicity of rock dust and charcoal powder enhanced with diatomaceous earth against rice weevil in maize stored by smallholder farmers

Direct partial oxidation of low-concentration methane to methanol with copper-based clay catalysts

Partial oxidation of methane to methanol (POMM) is an economic and environmental technology, especially for utilizing low-concentration methane resources in the explosive range. In this paper, mineral clays like sepiolite (SEP), attapulgite (ATP), montmorillonite (MMT), bentonite (BEN), kaolin (KAO) and diatomite (DIA) were used as supports to prepare copper-based clay catalysts by impregnation method and their performance in continuous direct POMM with O2 as oxygen source were tested. The methanol yields of these catalysts at 320 °C with feed ratio of CH4: O2: H2O = 2: 1: 8 exhibited the following order: Cu/KAO (145.26 μmol/gCu/h) > Cu/ATP (74.18 μmol/gCu/h) > Cu/SEP (63.99 μmol/gCu/h) > Cu/MMT (51.59 μmol/gCu/h) > Cu/DIA (42.29 μmol/gCu/h) > Cu/BEN (39.64 μmol/gCu/h). This demonstrated that copper-based clay catalysts were promising for use in POMM considering their economy and environmental acceptability. Additionally, these copper-based clay catalysts were characterized and it was found that different clays could tailor the interaction of Cu species with supports, alter the reducibility and surface acidity, thereby changing the methanol yield. What's more, it was confirmed that the superior methanol yield of Cu/KAO was attributed to its relatively more [Cu2O)]2+ sites with Cu–O, Cu–Si/Al and Cu–Cu coordination structures similar to that of copper-based zeolite catalysts.

Characterization of the Neurospora crassa Galactosaminogalactan Biosynthetic Pathway.

The Neurospora crassa genome has a gene cluster for the synthesis of galactosaminogalactan (GAG). The gene cluster includes the following: (1) UDP-glucose-4-epimerase to convert UDP-glucose and UDP-N-acetylglucosamine to UDP-galactose and UDP-N-acetylgalactosamine (NCU05133), (2) GAG synthase for the synthesis of an acetylated GAG (NCU05132), (3) GAG deacetylase (/NCW-1/NCU05137), (4) GH135-1, a GAG hydrolase with specificity for N-acetylgalactosamine-containing GAG (NCU05135), and (5) GH114-1, a galactosaminidase with specificity for galactosamine-containing GAG (NCU05136). The deacetylase was previously shown to be a major cell wall glycoprotein and given the name of NCW-1 (non-GPI anchored cell wall protein-1). Characterization of the polysaccharides found in the growth medium from the wild type and the GAG synthase mutant demonstrates that there is a major reduction in the levels of polysaccharides containing galactosamine and N-acetylgalactosamine in the mutant growth medium, providing evidence that the synthase is responsible for the production of a GAG. The analysis also indicates that there are other galactose-containing polysaccharides produced by the fungus. Phenotypic characterization of wild-type and mutant isolates showed that deacetylated GAG from the wild type can function as an adhesin to a glass surface and provides the fungal mat with tensile strength, demonstrating that the deacetylated GAG functions as an intercellular adhesive. The acetylated GAG produced by the deacetylase mutant was found to function as an adhesive for chitin, alumina, celite (diatomaceous earth), activated charcoal, and wheat leaf particulates.

Fabrication of functional diatomaceous earth with enhanced papain enzyme adsorption

Diatomaceous earth (DE) is a sedimentary rock comprising fossilized shells of diatoms, which are a type of algae. The shells of the diatoms are made of silicon dioxide, which is also the main component of DE. DE has excellent moisture absorption and desorption properties and is widely used as an adsorbent, abrasive, insulator, catalyst, and carrier in the stationary phase. It has also been widely studied for its application as a new silicon material in emerging growth fields, such as biosensors. However, because organic matter is adsorbed on the surface of DE, the organic matter must be removed to exploit the properties of mesoporous silica. In this study, the organic matter on the DE surface was removed by alkali treatment to expose the pores and increase the adsorption capacity. Additionally, papain was physisorbed onto DE using a rotator, and l-cysteine was added for papain activation. Under these optimised conditions, the activation of the papain enzyme was effective, resulting in improved DE performance. The adsorption power of DE was correlated with the amount of papain adsorbed, which, in turn, was correlated with its absorbance. Trichloroacetic acid was added to stop the reaction, and the absorbance was measured. The prepared samples were designated as papain/DE (P/DE) complexes. The final concentration of the P/DE was 1 mg/mL. In addition, cross-linked and non-cross-linked P/DE samples were prepared using N-hydroxysuccinimide and water-soluble carbodiimide in a 5:3 ratio and compared. The results showed that surface treatment and functionalisation of DE improved its functionality (enzyme activity), indicating its potential as a new DE material.

Preparation of ternary BiVO4/g-C3N4/diatomite composites for enhanced photodegradation of rhodamine B and formaldehyde

Efficient ternary BiVO4/g-C3N4/diatomite (BCNDE) composites were prepared using a strategy combining in situ polymerisation and self-assembly. The photocatalytic degradation efficiencies of BCNDE composites for rhodamine B (RhB) and formaldehyde (CH2O) were investigated. Compared with BiVO4 (BVO), g-C3N4 (CN) and BiVO4/g-C3N4 (BCN), BCNDE showed better photocatalytic performance for RhB and CH2O degradation. Notably, the 20-BCNDE composite demonstrated superior photocatalytic performance, achieved 99 % degradation of RhB under visible light (λ > 400 nm) within 60 min and 81 % degradation of CH2O gas (0.16 mg·L−1) within 40 min. Incorporation of porous microdisc-shaped diatomite (DE) significantly mitigated the agglomeration of the BCNDE composites, as confirmed by scanning electron microscopy (SEM). This structural feature enhanced the separation and migration of photogenerated electron-hole pairs, as evidenced by photoluminescence (PL) spectroscopy and electrochemical impedance spectroscopy (EIS) analyses. Zeta potential analysis at pH 7 revealed a negatively charged surface with a zeta potential of −8.9 mV, facilitating the attraction of photogenerated holes and inhibiting electron-hole recombination. This effectively inhibited the recombination rate of photogenerated electron-hole pairs, thereby significantly improving the photocatalytic performance of the material. These mechanisms were critical in boosting the photocatalytic degradation activities for RhB and CH2O. This study highlights the potential of BCNDE composites for environmental remediation applications, offering a promising approach for the development of efficient mineral-based photocatalytic materials.

Toxicity and morphological changes induced by diatomaceous earth & malathion against Tribolium castaneum

Toxicity and morphological changes induced by diatomaceous earth & malathion against Tribolium castaneum

The important role of diatomite on multifunctional modified separator of Li-S battery

The commercial applications of lithium-sulfur (Li-S) batteries are limited by decreased cycling performance caused by the shuttle effect of polysulfides, slower kinetic reaction rates, and lithium anode dendrites. This study demonstrates the important role of diatomite (DT) in regulating cycle performance of modified separator for Li-S batteries. A multifunctional separator (Co/NC/DT) with DT as a carrier assembled high loading cobalt nanocluster is prepared. The N-doped carbon is immobilized via Si-N bond between DT and N-doped carbon. The depth profiles of XPS indicate that the ratio of pyrrolic N to pyridinic N of Co/NC/DT reaches 5.31 at the etching of 100 nm versus 0.83 for Co/NC at surface, which suggesting that mainly N species is pyrrolic N after the addition of DT. Theoretical calculations confirm that cobalt nanoclusters grown on pyrrolic N-doped carbon have a lower adsorption energy for active materials compared to that on pyridinic N-doped carbon and can reduce the energy barrier, especially only 0.09 eV for reduction from Li2S6 to Li2S4. In-situ X-ray diffraction analysis confirms Co/NC/DT can effectively promote formation of Li2S. Lithium anode in-situ optical microscopy observation shows the modified separator could reduce lithium dendrites effectively. Li-S battery assembled with the modified separator can reach an initial capacity of 1331.3 mAh g−1 at 0.2 C and cycle 1500 cycles at 1.0 C with a decay of only 0.039% per cycle. Through regulation of DT, Co/NC/DT accelerates the conversion from long-chain sulfur to short-chain sulfur and Li+ transfer rate, resulting in improving cycling performance.

Feasibility of matrix solid-phase dispersion combined with HR-CS FAAS for determination of copper in milk-based infant foods

This study proposes, for the first time, the development of an analytical method using the matrix solid-phase dispersion (MSPD) for extraction of copper from infant formulas and milk-based foods for further determination using high resolution-continuum source flame atomic absorption spectrometry (HR-CS FAAS). MSPD parameters were investigated, and by employing a 0.25 g sample, 0.25 g of diatomaceous earth as a solid support, 1 mol/L HNO3 as the extraction solution, and 1 min of blending, higher agreements with reference values were obtained. The limit of detection of the method was 0.35 µg/g. Accuracy was assessed by comparing the results using the following methods: i) proposed method (MSPD/HR-CS FAAS); and ii) decomposition of samples by microwave-assisted digestion (MAD) and quantification by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GFAAS). The MSPD extracts were also quantified using HR-CS GFAAS. No significant difference was found between the results. The agreements ranged from 95 to 103 %, and no significant difference was observed between the results. Copper concentrations ranged from 0.40 to 3.8 μg g−1 using the proposed method, with relative standard deviations lower than 10 %. The proposed method proved to be efficient for the determination of copper in infant formulas and milk powder, offering advantages such quickness, simplicity, low cost, low energy consumption, reduced waste generation (due to the use of an aqueous extraction solution), utilization of materials from renewable sources (diatomaceous earth as a solid support), and minimized analyst exposure when compared to conventional sample preparation methods. These attributes align with the principles of Green Analytical Chemistry.

An Investigation into Diatomaceous Earth Stones: A New Tool in Paper Conservation

ABSTRACT This research explores the viability of using diatomaceous earth stone mats, a commercially manufactured, rigid, absorbent board marketed for home use (aka DE stones) as a sustainable tool in paper conservation. Analytical studies, including X-ray fluorescence, Fourier-transform infrared spectroscopy, gravimetry, colorimetry, accelerated aging, pH, solvent reactivity, and absorbency testing, were conducted at the National Archives and Records Administration on the DE stones and on Whatman® filter paper samples. The experiments with samples dried in direct contact with DE stones showed no undesirable transfer to the filter paper. Gravimetric analysis showed the drying rate of samples placed between DE stones was much more rapid than for samples placed between blotter or wool felt. Colorimetry before and after accelerated aging of samples dried in direct contact with DE stones showed no undesirable aging patterns. Successful case studies illustrate high potential for the use of DE stones in paper conservation treatments.

Time-Dependent Behavior of Diatomaceous Earth under Triaxial Compression and Its Modeling

Time-Dependent Behavior of Diatomaceous Earth under Triaxial Compression and Its Modeling

Insecticidal Efficacy of Diatomaceous Earth and Botanical Powders against Pulse Beetle, Callosobruchus analis F. in Stored Mung Bean (Vigna radiata L.)

The pulse beetle is the most damaging insect pest of legumes causing huge economic losses. The experiment was conducted to find out the insecticidal effects of diatomaceous earth (DE) combined with three botanical powders in three different combinations of 25% plant powder with 75% DE, 50% plant powder with 50% DE and 75% plant powder with 25% DE. The results indicated that the least number of adult beetles settled on grains treated with T9 (75% GP + 25% DE and T3 (75% NP + 25% DE) whereas maximum number of adult beetles settled in T4 (25% TP + 75% DE). After 168 hours, all the treatments showed significant mortality (100%) of adult beetles compared to control (43%). All the treatments reduced the number of eggs (3.60 to 6.80 eggs per 20 grains) in comparison to control (17.00). The maximum (28.80) days to adult emergence were documented in T9 whereas; minimum (21.40) days were recorded in untreated grains. Among all the treatments, T9: showed minimum emergence (36.40) of adult beetles whereas; the maximum (125.20) adults emerged in control. The lowest grain damage (5.50%) was observed in T9 as related to the maximum grain damage (28.96%) in the untreated control. The minimum weight loss (3.49%) was recorded in T9. The maximum weight loss (21.08%) was recorded in untreated grains. The use of diatomaceous earth in combination with garlic powder is recommended for the management of pulse beetle under storage conditions.

Evaluation of Bio-Stimulants for Active Growth, Yield and Shelf Life of Papaya cv. Red Lady

Bio-stimulants, which are natural substances aiding plant growth and resilience, are comprised of various organic and mineral compounds, serving as eco-friendly tools for sustainable farming. The research study was conducted at the Horticulture Farm of Agriculture at Lovely Professional University in Phagwara, Punjab, during the years 2023-24. The study employed a randomized block design with seven treatments replicated three times. Bio-stimulants were sprayed at 60, 90, 120 and 150 days after planting (DAP) on papaya plants cv. Red Lady to evaluate its effect on various growth, quality and shelf-life parameters. Various growth parameters including plant height, stem girth, canopy spread, petiole length of leaves, as well as floral characteristics such as days taken for flowering, height at initial flowering, number of flowers per node, fruit set percentage and yield-related parameters were evaluated. The study found significant effects of different bio-stimulant applications on papaya growth, flower and fruit production, fruit quality and shelf-life. Treatment T4 (RDF + Diatomaceous earth) showed notable improvements in growth parameters, while treatment T5 (RDF + Panchgavya) resulted in enhanced productivity, fruit quality and shelf-life. Overall, the study suggests that the application of Diatomaceous earth alongside fertilizers promotes vegetative growth, while Panchgavya application enhances flowering, fruiting and quality attributes, offering insights for optimizing papaya cultivation practices for improved yield and quality.