Natural Mineral Research Articles

Use of Waste from the Food Industry and Applications of the Fermentation Process to Create Sustainable Cosmetic Products: A Review

In recent years, the sustainability of cosmetic products has received growing interest from the cosmetic industry and consumers due to the recommendation of the implementation of the circular economy and the European Green Deal. The sustainable development strategy takes into account the reduction of waste and energy consumption, and covers all processes of producing and using cosmetics, starting from the method of obtaining raw materials, through to the process of producing cosmetics bulk, to the selection of packaging. Particularly, the selection of raw materials has a large impact on sustainability of cosmetic emulsion. One way of resource recovery is the use of agro-food by-products and discarded waste to produce cosmetic raw materials, because most of them possess value-added bioactive compounds, such as enzymes and nutrients with high functionality. Their recovery may be performed by more sustainable extraction processes, leading to natural oils, extracts, polymers, phytosterols, vitamins, minerals, and unsaturated fatty acids. A relatively new and innovative form of designing sustainable and bioavailable cosmetic raw materials is fermentation, where bioferments are obtained from plant-based and food waste raw materials. In addition, optimization of the emulsification process by applying low-energy methods is a crucial step in obtaining sustainable cosmetics. This allows not only a reduction in the carbon footprint, but also the preservation of the valuable properties of the used raw materials. The following paper discusses methods of creating sustainable cosmetic emulsions with energy-saving procedures and by using raw materials from food waste and the fermentation process.

Interpretation and origin determination of oil seepages using marine seismic data: a case study of the Western Continental Margin of India

This article discusses the experience of a joint using remote sensing data, marine seismic data and open geoscientific data to search for natural mineral oil seepages. The study was carried out as part of an assessment of oil prospects in the offshore sedimentary basins of the Arabian Sea on the west coast of the Indian Peninsula. The methodology is based on visual interpretation of natural and anthropogenic oil seepages using Sentinel-2 multispectral imageries. Modern offshore seismic data is used to establish the mineral origin of oil seepages by the presence of reservoirs and fault systems as possible sources of hydrocarbons and channels for their migration to the surface, respectively. The final map of detected oil seepages location is the result of research. Areas of natural mineral oil seepages accumulation confined to the western continental margin of India have been identified. Recommendations for exploration activities in the Kutch, Saurashtra and Kerala-Konkan offshore sedimentary basins were given. The acquired experience of visual interpretation of multispectral satellite data confirms efficiency of marine seismic data application for delineation of natural oil seepages of mineral origin in the areas of intensive navigation. The proposed methodology of research can be used as an indirect assessment of oil prospects in the Western Continental Margin of India and other areas of the world ocean.

Development of compound feed recipes for broiler chickens (13-28 days) using vermiculite

Recently, in the CIS countries and abroad, to compensate for the mineral deficiency of feed rations and reduce their cost, substances of natural origin have increasingly begun to be used: zeolites, travertines, sapropels, bentonites, etc. The prlackblem of the widespread use of natural minerals in the diet of farm animals and poultry represents a pressing issue, given their distinctive properties, waste-free technology, environmental friendliness, and relatively low cost. One of these minerals suitable for use in poultry nutrition is vermiculite (hydromica, hydrous silicate of magnesium and iron of variable composition). The purpose of the study is to determine the physicochemical composition of vermiculite from the Kulantau deposit, and its use as a mineral in the production of animal feed and development of compound feed recipes for broiler chickens Cobb500. The physicochemical parameters of vermiculite, a natural mineral, have been determined. The research analyses were carried out in the research laboratory for assessing the quality and safety of food products of the Almaty Technological University. Feed recipes were developed at LLP “AGRO FIT KAPSHAGAY”. The compound feed recipes for Cobb 500 broiler chickens of 13-28 days were tested at JSC “Alel agro”, in poultry house No. 3.

Room-temperature fabrication of fluorinated covalent organic polymer @ Attapulgite composite for in-syringe membrane solid-phase extraction and analysis of domoic acid in aquatic products

A novel fluorinated covalent organic polymer @ attapulgite composite (F-COP@ATP) was prepared at room temperature for in-syringe membrane solid-phase extraction (SM-SPE) of domoic acid (DA) in aquatic products. Natural ore ATP has the advantages of low cost, good mechanical strength and abundant hydroxyl group on its surface, and in-situ modified F-COP layer can provide abundant adsorption sites. F-COP@ATP combining the advantages of F-COP and ATP, becomes an ideal adsorbent for DA extracting. Moreover, a high-throughput sample preparation strategy was carried out by using the F-COP@ATP membrane as syringe filter and assembling syringes with a ten-channel injection pump. In addition, the experimental factors were optimized, such as pH of extract, amount of adsorbent, velocity of extraction and desorption, type and volume of desorption solvent. The DA analytical method was established by SM-SPE-HPLC/tandem mass spectrometry. The method had a wide linear range with low limit of detection (0.344 ng/kg) and low limit of quantification (1.14 ng/kg). F-COP@ATP membrane can be reused more than five times. The method realized the analysis of DA in scallop and razor clam samples, which shows its application prospect in practical analysis. This study provided an efficient, low-energy and mild idea for preparing other reusable natural mineral ATP-based composite materials for separation and enrichment, which reduces the experimental cost and is closer to environmental protection and green chemistry to a certain extent.

Thermal Behavior of Ceramic Bodies Based on Fly Ash and Smectites

Clay minerals have a great influence on the resulting properties of ceramic bodies. Fly ash as a waste material from burning black coal in power plants is a potentially valuable source of oxides (Al2O3, SiO2 or Fe2O3) for this production. Considering the process of ceramic firing, it is important to understand the thermal behavior of individual ingredients. The thermal behavior of natural smectite minerals (montmorillonite, beidellite, hectorite and nontronite) and their mixtures with added fly ash at different ratios (10%, 30% and 50%) was investigated. The phase analysis was obtained using X-ray diffraction and FT-IR spectroscopy. Under heating to 1200 °C, the structural changes of smectites were divided into four steps including dehydration, dehydroxylation, decomposition and crystallization of new phases. The addition of fly ash caused a shift in the reaction temperatures for all the mentioned phases. These changes were most noticeable for mixtures with hectorite; on the contrary, they were least noticeable for beidellite mixtures. Total mixture mass loss continually decreased with increasing fly ash amount. The obtained experimental thermal data can be applicable not only in the production of ceramic bodies or energy waste processing but also in construction and ensuring the safety of municipal waste landfills.

Removal of Emerging Organic Pollutants by Zeolite Mineral (Clinoptilolite) Composite Photocatalysts in Drinking Water and Watershed Water

One of the most challenging problems for people around the world is the lack of clean water. In the past few decades, the massive discharge of emerging organic pollutants (EOPs) into natural water bodies has exacerbated this crisis. Considerable research efforts have been devoted to removing these EOPs due to their biotoxicity at low concentrations. Heterogeneous photocatalysis via coupling clay minerals with nanostructured semiconductors has proven to be an economical, efficient, and environmentally friendly technology for the elimination of EOPs in drinking water and watershed water. Natural zeolite minerals (especially clinoptilolites) are regarded as appropriate supports for semiconductor-based photocatalysts due to their characteristics of having a low cost, environmental friendliness, easy availability, co-catalysis, etc. This review summarizes the latest research on clinoptilolites used as supports to prepare binary and ternary metal oxide or sulfide semiconductor-based hybrid photocatalysts. Various preparation methods of the composite photocatalysts and their degradation efficiencies for the target contaminants are introduced. It is found that the good catalytic activity of the composite photocatalyst could be attributed to the synergistic effect of combining the clinoptilolite adsorbent with the semiconductor catalyst in the heterogeneous system, which could endow the composites with an excellent adsorption capacity and produce more e−/h+ pairs under suitable light irradiation. Finally, we highlight the serious threat of EOPs to the ecological environment and propose the current challenges and limitations, before putting the zeolite mineral composite photocatalysts into practice. The present work would provide a theoretical basis and scientific support for the application of zeolite-based photocatalysts for degrading EOPs.

CO2 -ის დაჭერის პროცესში, ნამწვი აირები - კლინოფთილოლითი დისპერსულ სისტემაში მოსალოდნელ პროცესთა თერმოდინამიკური პროგნოზირება

CO2 generated in production processes and emitted into the atmosphere with flue gases is the cause of the greenhouse effect and negative processes of global climate change towards warming. Therefore, prevention of CO2 emissions into the atmosphere is the research topic of the article. CCUS type climate change mitigation projects are being developed in Georgia, where natural zeolite mineral containing clinoptilolite, Khekordzula tuff is a sorbent for CO2 capture. Its formation enthalpy (ΔfH0 298), Gibbs free energy (ΔfG0 298), and entropy (ΔfS 0 298) have not been studied, also temperatures of its thermal dehydration, CO2 adsorption, expected chemisorption and other thermodynamic quantities. It was determined: Enthalpy of clinoptilolite tuff formation (ΔfH0 298=-39826 kJ/mol), Gibbs free energy (ΔfG0 298=-36735 kJ/mol), entropy (ΔfS 0 298=-10.37 kJ/K-mol); Temperatures of dehydration (94.800C), CO2 capture using it (physical-96.5700C), start of chemo-sorption (95.2400C) and pressure corresponding to these temperatures (745, 636, 534) mm Hg. Tuff can be successfully used for CCUS from flue gases.

Advanced oxidation of polycyclic aromatic hydrocarbons in tropical soil: Self-catalytic utilization of natural iron contents in an oxygenation reactor supported with persulfate

The catalysts derived from natural iron minerals in the advanced oxidation process offer several advantages. However, their utilization in soil remediation is restricted due to the presence of soil impurities, which can inhibit the catalytic activity of these minerals. The soils in tropical regions exhibit lower organic matter content, limited cation exchange capacity, and are non-saline, this enhances the efficiency of utilizing natural iron minerals from tropical soil as a catalyst. In this regard, the catalytic potential of naturally iron-bearing tropical soil was investigated to eliminate phenanthrene (PHE), pyrene (PYR), and benzo[α]pyrene (B[α]P) using an oxygenated reactor supported with persulfate (PS). The system showed an efficient performance, and the removal efficiencies under the optimum conditions were 81 %, 73 %, and 86 % for PHE, PYR, and B[α]P, respectively. This indicated that the catalytic activity of iron was working efficiently. However, there were changes in the soil characteristics after the remediation process such as a significant reduction in iron and aluminum contents. The scavenging experiments demonstrated that HO• had a minor role in the oxidation process, SO4•− and O2•− emerged as the primary reactive species responsible for the effective degradation of the PAHs. Moreover, the by-products were monitored after soil remediation to evaluate their toxicity and to propose degradation pathways. The Mutagenicity test showed that two by-products from each PHE and B[α]P had positive results, while only one by-product of PYR showed positive. The toxicity tests of oral rat LD50 and developmental toxicity tests revealed that certain PAHs by-products could be more toxic from the parent pollutant itself. This study represents a notable progression in soil remediation by providing a step forward in the application of the advanced oxidation process (AOP) without requiring additional catalysts to activate oxidants and degrade pollutant PAHs from the soil.

FinTech adoption in achieving ecologically sustainable mineral management in Asian OBOR countries – A cross-section and time autoregressive robust analysis

The balance between economic activity, economic growth, and ecosystem is a need of the time. Belt and Road Initiative countries working on the One Belt and One Road project (OBOR), constituting 130 countries, are participating with China to achieve growth via trade. These countries, where trade and commerce have influence, are rich in natural minerals as well as natural habitat and biodiversity. Along with infrastructural efforts, the world is also experiencing a growth in technology 4.0, specifically its gains in terms of financial innovation. This study has explored 27 countries from the Asian OBOR group and assessed the potential moderating role of FinTech on resource extraction sustainability. The results from multi-dimensional, long-term, and robust estimates showed that resource rents harm environmental performance and FinTech positively moderates this relationship. This study is instrumental for the policymakers in quantifying the hampering spillover/spatial effects and diminishing time horizon policy effectiveness.

Analysis of The Causes of Defects In Products in Cup Filing Machines

Drinking water is good water and can be in natural form or processed like sea water for desalination, itmust meet the drinking water standards set. Drinking water standards are divided into ordinary water, mineral water, natural mineral water and bottled water. AMDK is drinking water that has been treated, packaged and is safe for direct consumption in accordance with industrial standards in Indonesia. Manufacturing machines including glass, bottle and gallon filling machines often experience product defects outside the planned schedule and machine damage causes production to stop, thereby reducing machine performance and suggestions and input for improvements so that it can run as desired.

Insight into heterogeneous photo-Fenton degradation of naphthol by natural magnetite: Redundancy analysis and toxicity assessment

Magnetite is a ubiquitous iron mineral in nature and its iron ions are usually isomorphically substituted by Ti and V cations, which shows a high ability for degradation of organic contaminants via the photo-Fenton process. However, numerous reports pay more attention to the activity of synthetic magnetite rather than natural magnetite. Here, three types of natural magnetite (HG01, HG02, and GCL01) with different Ti and V contents were investigated from the perspective of the difference in structural property, catalytic activity, H2O2 decomposition, and reactive oxygen species generation. Structural characterization exhibited that the purity of natural magnetite obeyed the order: GCL01 > HG02 > HG01. HG01 contained the highest Ti content in the form of ilmenite, followed by HG02 and GCL01. Moreover, HG01 yielded the highest photo-Fenton catalytic activity with 99.5 % of naphthol degradation and 96.0 % of H2O2 decomposition after 60 min reaction. The superior activity of HG01 was attributed to the relatively high Ti and V content as demonstrated by redundancy analysis. Mechanistic investigation implied that the Ti and V in the octahedral sites of the magnetite surface can accelerate the electron transfer from Fe(III) to Fe(II), resulting in higher Fenton activity. Besides, ilmenite in HG01 enhanced naphthol degradation because H2O2 accelerated the separation of photoelectron-holes pairs to promote O2− production. Furthermore, as revealed by gas chromatography-mass spectrometry and the toxicity of identified products predicted by the ECOSAR model, the toxicity of naphthol can effectively reduce accompanied by the harmless products generated. The high reusability, low iron ions residual in water, harmless end products, and easily recycled with magnetic separation suggest that natural magnetite has a promising application prospect for wastewater purification.

Application and environmental impact of loose nanofiltration in surface water treatment

Loose nanofiltration (LNF) membranes with a molecular weight cutoff (MWCO) of about 1000 Da have great potential for high selectivity between natural organic matter (NOM) and mineral salts. Therefore, they are interesting for treatment plants for purifying oligotrophic lake waters with an elevated NOM concentration. This study was conducted to determine the design and operational expenses as well as the environmental impact of an LNF-based drinking water treatment process that removes NOM from Finnish surface water. Two LNF membranes with similar MWCOs were selected, and the results were compared to ultrafiltration, nanofiltration, and conventional treatment. One LNF membrane demonstrated a rejection rate of NOM higher than 95 % and a low rejection rate of hardness at about 40 %, while the other LNF membrane performed similarly to an ultrafiltration membrane. The LNF-based treatment process would increase operational expenses by 53—69 % but at the same time decrease the environmental impact by >18 %. Improved removal of aromaticity and low molecular weight compounds could lower the disinfection byproduct formation potential and microbial growth in the network, thus reducing the required chlorine dosage in the network and possibly bringing further cost savings.

Insight into the crystal facet-dependent Cr(VI) reduction: A comparative study of pyrite {100} and {111} facets

The migration and transformation of hexavalent chromium (Cr(VI)) in the environment are regulated by pyrite (FeS2). However, variations in pyrite crystal facets influence the adsorption behavior and electron transfer between pyrite and Cr(VI), thereby impacting the Cr(VI) reduction performance. Herein, two naturally common facets of pyrite were synthesized hydrothermally to investigate the facet-dependent mechanisms of Cr(VI) reduction. The experimental results revealed that the {111} facet exhibited approximately 1.30–1.50 times higher efficiency in Cr(VI) reduction compared to the {100} facet. Surface analyses and electrochemical results indicated that {111} facet displayed a higher iron-sulfur oxidation level, which was affected by its superior electrochemical properties during the reaction with Cr(VI). Density functional theory (DFT) calculations demonstrated that the narrower band gap and lower work function on {111} facet were more favorable for the electron transfer between Fe(II) and Cr(VI). Furthermore, different adsorption configurations were observed on {100} and {111} surfaces due to the unique arrangements of Fe and S atoms. Specifically, O atoms in Cr2O72− directly bound with the S sites on {100} but the Fe sites on {111}. According to the density of states (DOS), the Fe site had better reactivity than the S site in the reaction, which appeared to be related to the fracture of S-S bonds. Additionally, the adsorption configuration of Cr2O72− on {111} surface showed a stronger adsorption energy and a more stable coordination mode, favoring subsequent Cr(VI) reduction process. These findings provide an in-depth analysis of facet-dependent mechanisms underlying Cr(VI) reduction behavior, offering new insights into studying environmental interactions between heavy metals and natural minerals.

Oyster shell-modified lignite composite in globular shape as a low-cost adsorbent for the removal of Pb2+ and Cd2+ from AMD: Evaluation of adsorption properties and exploration of potential mechanisms

A low-cost composite adsorption material has been synthesized from fishery wastes and natural minerals to address challenges such as ecological balance destruction caused by high concentrations of Pb and Cd in acid mine drainage (AMD), unreasonable use of low-caloric lignite, and environmental pollution caused by idle accumulation of oyster shells. This new adsorbent can effectively treat AMD by improving acidity and adsorbing Pb2+ and Cd2+. In this study, oyster shell-modified lignite composite in globular shape (OSL-G) was synthesized by using pyrolyzed oyster shell and lignite, with the addition of bentonite adhesive. The adsorption properties of OSL-G on AMD were evaluated, and the potential mechanism of OSL-G repairing AMD was explored. The results showed that when the mass ratio of oyster shell to lignite was 1:1, oyster shell-modified lignite composite (OSL) was synthesized at 900 °C for 20 min. When the adhesive content was 15.50 %, the roasting temperature was 640 °C, and the roasting time was 2.35 h, OSL-G was synthesized and the adsorption effect was the best. The OSL-G could effectively treat AMD with pH 4 ∼ 5 and initial Pb2+ and Cd2+ concentrations of 10 mg/L within 600 min at a dosage of 4 g/L. The OSL-G adsorption process followed the quasi-second-order kinetic model and the Freundlich model. The maximum adsorption saturation capacities of Pb2+ and Cd2+ were 107.2821 mg/g and 8.3777 mg/g at 298.15 K, respectively. The adsorption process was a multistep controlled spontaneous endothermic process. The potential mechanism was mainly the adsorption-condensation coexistence results of electrostatic adsorption, neutralization precipitation, ion exchange, and surface complexation. The removal rates of Pb2+ and Cd2+ of the recovered OSL-G (ROSL-G) were still high, reaching 57.26 % and 50.38 % after 5 times of adsorption–desorption, respectively. The applicability of ROSL-G after adsorption–desorption for other heavy metal components in AMD proved its good application potential. This study suggested that OSL-G can be used as a promising environmentally friendly adsorbent for AMD. This study provided a broad picture of the management and reuse possibilities of fishery wastes and natural mineral resources, and addressed established, current, and potential strategic needs, particularly in terms of sustainability challenges and ecological civilization construction.

Fabrication of robust and versatile ionic thermoelectric devices of natural clay minerals

Due to advantages like high Seebeck coefficients, simple fabrication techniques, and use of abundant elements, ionic thermoelectric (i-TE) devices are emerging to be an ideal tool for harvesting low-grade waste heat. However, high dependence on humidity and poor thermal stability of organic polymers/polyelectrolytes/ionic liquids are restricting the utility area of i-TE devices. To expand the horizon of applicability, here, thermally and chemically robust natural clay minerals are explored for fabricating i-TE devices. Devices prepared with exfoliated layers of clay showed high Seebeck coefficients (6 ± 0.8 mV/K), which is significantly improved (up to 140 %) upon functionalization with the –SO3H groups (14.4 ± 0.4 mV/K). i-TE devices of clay exhibit unique advantages like thermal robustness and water-induced damage healing ability. These devices did not show any sign of deterioration even after exposure to 300 °C. Along with waste heat, clay-i-TE devices can also convert abundant sunlight energy into electricity. Upon being coated with polyvinyl alcohol (PVA), borax, and LiCl-based hydrogel the performance of the i-TE device at low-humidity conditions is drastically improved. The possibility of practical utility of clay-based i-TE devices was demonstrated in areas like fire alarms, touch sensors and electricity generation from hot water steam.

Nutrition Design Modeling Method Development for Structural Analysis and Formulation Modeling of Giresun Hazelnut Using Field Emission Gun – Scanning Electron Microscope (FEG-SEM)

The structure analysis and composition modeling of Giresun hazelnuts were first time investigated to develop a nutrition design modeling method using the Field Emission Gun – Scanning Electron Microscope (FEG-SEM). Texture analysis of the hazelnut has shown cube-like oily surface, non- fibrous non-porous spreading structure, and particularly high elemental value of carbon (44.92%) and oxygen (45.562%), and P (1.22%), K (1.21%), Cl (7.09%) mineral elements stating that the Giresun hazelnut is oily spreading structure model, and natural oil carbohydrate and mineral models. The Giresun hazelnut was determined to be suitable for finely grinding to produce hazelnut flour and production of hazelnut nutrition assortments. The Giresun hazelnut was ground with water to produce white colored homogenized nonclotting vegetable type hazelnut milk with hazelnut aroma without additives.

Role of the surface layer of epoxy resin

Water pollution threatens human health, and the safe supply of drinking water has been recognized as a problem worldwide. The increasing accumulation of heavy metals in water from various sources has led to the search for effective and environmentally friendly treatment methods and materials for their removal. To impart the necessary characteristics to minerals, in particular to improve sorption properties, one of the methods is modification. Modern technologies using sorbents require qualitatively new sorption materials with increased capacity and high selectivity of action. Epoxy resins are widely used as a base material in the coating field due to their advantages including adsorption properties. In this work, shungite from the Koksu deposit and Shankhanai zeolite were used as natural sorbents for modification. The purpose of this work is to study the interaction of epoxy resin ED-20 with the surface of a natural sorbent through a layer of polyethylene polyamine. Methodology. To study the surface of the prepared samples, methods such as infrared spectroscopy, gravimetry and the temperatureprogrammed desorption method were used. Results and discussion. This article presents the results of IR spectroscopic analysis of natural sorbents shungite and zeolite modified with epoxy resin ED-20 and polyethylene polyamine. The obtained surface epoxy layers were studied for resistance to aqueous environments of varying acidity for 90 days. The acid-base properties of the surface layers of modified sorbents were studied by the method of temperature-programmed ammonia desorption. Conclusion. By modifying shungites and zeolites with polyethylene polyamine, followed by cross-linking them on the surface of a natural mineral with ED-20 epoxy resin, a durable layer of epoxy resin was obtained.

Synergistic Effects of Silica-Supported Iron-Cobalt Catalysts for CO2 Reduction to Prebiotic Organics.

To test the ability of geochemical surfaces in serpentinizing hydrothermal systems to catalyze reactions from which metabolism arose, we investigated H2-dependent CO2 reduction toward metabolic intermediates over silica-supported Co-Fe catalysts. Supported catalysts converted CO2 to various products at 180 °C and 2.0 MPa. The liquid product phase included formate, acetate, and ethanol, while the gaseous product phase consisted of CH4, CO, methanol, and C2-C7 linear hydrocarbons. The 1/1 ratio CoFe alloy with the same composition as the natural mineral wairauite yielded the highest concentrations of formate (6.0 mM) and acetate (0.8 mM), which are key intermediates in the acetyl-coenzyme A (acetyl-CoA) pathway of CO2 fixation. While Co-rich catalysts were proficient at hydrogenation, yielding mostly CH4, Fe-rich catalysts favored the formation of CO and methanol. Mechanistic studies indicated intermediate hydrogenation and C-C coupling activities of alloyed CoFe, in contrast to physical mixtures of both metals. Co in the active site of Co-Fe catalysts performed a similar reaction as tetrapyrrole-coordinated Co in the corrinoid iron-sulfur (CoFeS) methyl transferase in the acetyl-CoA pathway. In a temperature range characteristic for deeper regions of serpentinizing systems, oxygenate product formation was favored at lower, more biocompatible temperatures.

Activation of iron oxide minerals in an aquifer by humic acid to promote adsorption of organic molecules

In aquifers, the sequestration and transformation of organic carbon are closely associated with soil iron oxides and can facilitate the release of iron ions from iron oxide minerals. There is a strong interaction between dissolved organic matter (DOM) and iron oxide minerals in aquifers, but the extent to which iron is activated by DOM exposure to active iron minerals in natural aquifers, the microscopic distribution of minerals on the surface, and the mechanisms involved in DOM molecular transformation are currently unclear. This study investigated the nonbiological reduction transformation and coupled adsorption of iron oxide minerals in aquifers containing DOM from both macro- and micro perspectives. The results of macroscopic dynamics experiments indicate that DOM can mediate soluble iron release during the reduction of iron oxide minerals, that pH strongly affects DOM removal, and that DOM is more efficiently degraded at low rather than high pH values, suggesting that a low pH is conducive to DOM adsorption and oxidation. Spherical aberration-corrected scanning transmission electron microscopy (SACTS) indicates that the reacted mineral surfaces are covered with large amounts of carbon and that dynamic agglomeration of iron, carbon, and oxygen occurs. At the nanoscale, three forms of DOM are found in the mineral surface agglomerates (on the surfaces, inside the surface agglomerates, and in the polymer pores). The microscopic organic carbon and iron mineral reaction patterns can form through oxidation reactions and selective adsorption effects. Fourier transform ion cyclotron resonance mass spectra indicate that both synergistic and antagonistic reactions occur between DOM and the minerals, that the release of iron is accompanied by DOM decomposition and humification, that large oxygen- and carbon-containing molecules are broken down into smaller oxygen- and carbon-containing compounds and that more molecules are produced through oxidation under acidic rather than alkaline conditions. These molecules provide adsorption sites for sediment, meaning that more iron can be released. Microscopic evidence for the release of iron was acquired. These results improve the understanding of the geochemical processes affecting iron in groundwater, the nonbiological transformation mechanisms that occur at the interfaces between natural iron minerals and organic matter, groundwater pollution control, and the environmental behavior of pollutants.

Halogen‐free boron‐based hybrid system for enhancing flame retardancy, mechanical and thermal properties of epoxy

AbstractThis study aims to increase the flame retardancy of epoxy‐based composites by using various flame retardants together with colemanite filler (CLM), which is a very mineral‐rich boron type. As a flame retardant, aluminum hydroxide (Al(OH)3) and boron‐containing compounds: borax (BRX) and natural minerals (tincal (TNC) and colemanite (CLM)), as well as barium metaborate (BaMB) synthesized by us were used. Scanning electron microscopy (SEM), x‐ray powder diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), contact angle (CA), and particle size analysis were used to characterize the composites and additives. All boron compounds increased the thermal stability of the composites. Except for the ER/CLM‐BaMB composite, other composites' surface contact angles were over 90°. In terms of both combustion and thermal properties, the best CLM‐BaMB‐Al(OH)3‐TNC ratio was determined as 15:5:15:15. The tensile strength, self‐extinguishing time, estimated and experimental Limited Oxygen Index (LOI) values for this composite were determined as 96 MPa, 65 s, 29.6%, and 25%, respectively. In addition, ANOVA was applied to determine the effect of hybrid filler type and different weight ratios on the mechanical properties of composites.