Search Results (9)

This article provides information on the processing of chromium-containing waste from the Aktobe ferroalloy compounds plant using chemical reagents followed by high-temperature heat treatment for the synthesis of a composite chromite pigment used in the textile industry. This technology was developed for the first time for the purpose of recycling industrial waste and rational use of natural resources. The obtained pigments were analyzed by the X-ray phase of a D878-PC75-17.0 incident beam monochromator and the phase composition of the composite chromite pigment was studied. The thermogravimetric analysis of the composite chromite pigments was performed using a TGA/DSC 1HT/319 analyzer to determine the change in mass with time and temperature. According to the TGA results, the mass loss was determined to be 0.18% of the total mass. The elemental composition of the composite chromite pigment was determined using a JEOL JSM-6490 LV SEM device and the content of chromium oxide (Cr₂O₃) was determined, which reached up to 50%. The thermodynamic patterns of the processes occurring during the production of chromite pigments were studied using the integrated Chemistry software pack HSC-6. The results of testing printed and processed cotton and composite fabrics by the proposed method showed that the color fastness to washing and wet and dry friction is 4 points and the wear resistance assessment is 4860 and 6485 cycles, respectively. Composite chromite pigment based on technogenic wastes is recommended for use in various coloring compositions, including those used for printing on cotton and composite fabrics. Full article

Urban heat islands (UHI) are a growing issue due to urbanization, causing citizens to suffer from the inadequate thermal properties of building materials. Therefore, the need for climate-resistant infrastructure is crucial for quality of life. Phase change materials (PCMs) offer a solution by being incorporated into construction materials for thermoregulation. PCMs store and release heat as latent heat, adjusting temperatures through phase changes. Polymeric phase change fibers (PCFs) are an innovative technology for encapsulating PCMs and preventing leaks. This study produced PCFs via wet-spinning, using commercial cellulose acetate (CA, Mn 50,000) as the sheath and polyethylene glycol (PEG 2000) as the core. The PCFs were cut using a hot-cutting method at three different temperatures and washed with distilled water. Morphological analysis was conducted with a bright-field microscope, and chemical analysis was performed using Fourier transform infrared spectroscopy (FTIR) before and after controlled washing. Additionally, the washing baths were analyzed by UV-visible spectroscopy to detect PEG. The PCFs displayed a well-defined core-shell structure. Although some PEG 2000 leakage occurred in unsuccessful cuts, cuts at 50 °C showed sealed ends and less material in the baths, making it viable for civil engineering materials. Full article

Because of the requirements for accelerating the construction of a green, low-carbon, and recycling economy development system, the petrochemical industry has been paying attention to green and low-carbon transformations and innovations. Oily sludge is a type of bulk hazardous solid waste from various sources that significantly harms the environment. Chemical heat washing of oily sludge represents a large proportion of the treatment technology for oily sludge, which can be used individually and has many applications in joint treatment with other processes. However, research on the formulation of cleaning agents for this process has mainly focused on the surfactant at this stage, and many studies have demonstrated the secondary pollution of surfactant; thus, research on reducing or replacing surfactants as cleaning agents has been conducted. This review highlights the research progress of chemical heat washing of oily sludge according to the classification of cleaning agents and describes the reasons for the stabilization of currently recognized oily sludge, the chemical heat washing process, and the mechanism of oil–soil separation. Finally, the research direction for new emulsions as new cleaning agents to replace surfactants is set out. Full article

This article proposes an innovative two-stage technology for biomass torrefaction generating high-quality biochar, more specifically biocoal, as solid fuel, and offering a promising solution to the challenges posed by the combustion of biomass. In particular, the higher quality of biochar as solid fuel reduces the build-up of unmanageable deposits on fired surfaces, as these deposits inhibit heat transfer and reduce the efficiency of biomass boilers. The proposed two-stage technology involves torrefaction in a hearth-type reactor at temperatures up to 250 °C, followed by a subsequent stage of cooling achieved through washing with water. The two-stage torrefaction technology is integrated within a vertical hearth reactor vessel composed of three superimposed trays serving for biomass input, torrefaction, and water washing combined with biomass cooling, respectively. Upon contact with torrefied biomass, cooling water turned into water vapor; hence, eliminating the requirement for subsequent biomass separation and drying. The system was tested on sunflower husk, and results showed a reduction in the content of problematic elements such as alkali metal chlorides or sulfur compounds in biochar ash, suggesting lower corrosion rates of convective heating surfaces of the boiler under ash sediments. It is hypothesized that, while water exited hot biomass in the form of water vapor instead of liquid water, as is typically the case in water-washing processes, a share of undesirable elements may still have been removed from biomass through vaporization, without necessitating any additional process for ash removal. Hence, the index values calculated according to the chemical analysis of biomass ash suggested that sunflower husk biochar (biocoal) resulting from the proposed two-stage torrefaction process may display fuel characteristics similar to biomasses whose combustion ash may form reduced levels of deposits on boiler surfaces. Therefore, the proposed technology holds the potential to improve solid fuel characteristics of biomass, targeting enhanced efficiency and sustainability of biomass-fired power plants. Full article

Prolonged development of ore deposits, ore beneficiation and metallurgical smelting of concentrates result in the accumulation of wastes, forming large-scale dumps and sludge ponds negatively affecting the environment and human health. The creation and introduction of industrial waste treatment technologies will make it possible to dispose of them with the production of valuable commercial products and improve the environmental situation. In a research article on chemical beneficiation with the subsequent gravitational beneficiation of chrome-containing slurry tailings of Donskoy Ore-Mining and Beneficiation Plant (DOMBP), which processes chrome ore of the Kempirsay deposit in the Republic of Kazakhstan, Aktobe region, having considerable stocks of such waste is presented. The chromium-containing slurry tailings were heat-treated at 1100 °C, sintered with ammonium sulfate, water and sulfuric acid in a defined ratio at 300 °C, and then the resulting sinter was leached with water at 90 °C. The cake was washed to separate the liquid part from the solid part. The solid precipitate is the chromium-containing cake, which is upgraded by gravity concentration to a grade concentrate for ferroalloy production. When the solution is evaporated, magnesium sulfate with ammonium sulfate forms the Tutton’s salt ammoshenite. High-throughput chromium oxide extraction of 93.9% was achieved as a result of the research, and three products were obtained: (1) standard chromium concentrate with 49.48% Cr₂O₃ content, (2) ammoshenite used as a nitrogen–magnesium fertilizer and (3) forsterite, which is concentrated in gravity concentration tailings and can be used in the production of refractory minerals. Full article

The fragile paper is treated to improve the stability and appearance of the paper artifact, such as washing, lining, deacidification, and reinforcement. During the above treatments, paper documents inevitably make contact with water directly, leading to the appearance change, stability decrease, and migration or fading of anionic water-sensitive dyes, which are seriously harmful to information security. Herein, Hydroxypropyltrimethyl ammonium chloride chitosan (HACC) nanoparticles were employed for the reinforcement and concomitant inhibition of anionic water-sensitive dye migration on fragile paper. HACC nanoparticles were prepared through physical ball grinding method and characterized via LPSA, SEM, TEM, XRD and FTIR. To evaluate the protective potential of HACC nanoparticles coating, the chemical and mechanical properties of coated and uncoated papers were evaluated after dry heat and hygrothermal accelerated aging. Additionally, good color stability of anionic water-sensitive dyes was observed on the paper coated with HACC nanoparticles after lining technology. Finally, the interaction mechanism between the anionic water-sensitive dyes and HACC nanoparticles was analyzed using an ultraviolet spectrophotometer and FTIR. The as-proposed technique can provide technical support to improve the mechanical properties of fragile paper and enhance the anionic water-sensitive dyes stability in the aqueous phase. Full article

Researchers around the world are developing technologies to minimize carbon dioxide emissions or carbon neutrality in various fields. In this study, the dry spinning of regenerated silk fibroin (RSF) was achieved as a proof of concept for a process using ionic liquids as dissolution aids and plasticizers in developing natural polymeric materials. A dry spinning equipment system combining a stainless-steel syringe and a brushless motor was built to generate fiber compacts from a dope of silk fibroin obtained by degumming silkworm silk cocoons and ionic liquid 1-hexyl-3-methyl-imidazolium chloride ([HMIM][Cl]) according to a general method. The maximum stress and maximum elongation of the RSF fibers were 159.9 MPa and 31.5%, respectively. RSF fibers containing ionic liquids have a homogeneous internal structure according to morphological investigations. Elemental analysis of fiber cross sections revealed the homogeneous distribution of nonvolatile ionic liquid [HMIM][Cl] in RSF fibers. Furthermore, the removal of ionic liquids from RSF fibers through impregnation washing with organic solvents was verified to enhance industrial applications. Tensile testing showed that the fiber strength could be maintained even after removing the ionic liquid. Thermogravimetric analysis results show that the organic solvent 1,1,1,3,3,3-hexafluoro-2-propanol is chemically coordinated to silk fibroin and, as a natural polymer, can withstand heat up to 250 °C. Full article

Due the increasingly stringent environmental regulations and sustainable development-induced pressures to increase efficiency, the world faces new challenges. For this reason, the production of structural materials with controlled properties has become urgent. Due to their excellent mechanical and chemical properties and energy-efficient production methods, geopolymers have remarkable potential in higher value-added applications. This potential application exceeds their historical use as environmentally friendly substitutes for Portland cement. The aim of the present research is to produce metakaolin-based geopolymer foams using the combined technique of saponification/peroxide decomposition/gel casting. Concerning physical properties, the effect of H₂O₂ concentration, the type and amount of stabiliser and the addition of slag were investigated. XRD, FTIR, SEM, CT and thermogravimetric analyses were performed to characterise the material structure. Multifunctional geopolymer foams were developed that can be made free of organic matter and cracks through the optimisation of technological parameters (heat treatment, washing and firing). Such high strength (8.9 MPa), lightweight (~499 kg/m³) and low thermal conductivity (~0.041 W/mK) foams can be used as thermal insulating materials to reduce the energy loss of buildings. Due to their high open porosity (~77.7 vol%) and specific surface area (~4.3 m²/g), foamed geopolymers can function as catalyst supports in many physicochemical applications. Full article

In this article, we introduce for the first time, a method to manufacture cellulose based electrically conductive non-woven three-dimensional (3D) structures using the foam forming technology. The manufacturing is carried out using a minimum amount of processing steps, materials, and hazardous chemicals. The optimized solution applies a single surfactant type and a single predefined portion for the two main processing steps: (1) the dispersing of nanocellulose (NC) and carbon nanotubes (CNT) and (2) the foam forming process. The final material system has a concentration of the used surfactant that is not only sufficient to form a stable and homogeneous nanoparticle dispersion, but it also results in stable foam in foam forming. In this way, the advantages of the foam forming process can be maximized for this application. The cellulose based composite material has a highly even distribution of CNTs over the NC network, resulting a conductivity level of 7.7 S/m, which increased to the value 8.0 S/m after surfactant removal by acetone washing. Also, the applicability and a design product case ‘Salmiakki’ were studied where the advantages of the material system were validated for a heating element application. Full article