Partial Replacement Research Articles

Investigating the Viability of Rubber Crumbs from Waste Tyres as Partial Replacement for Coarse Aggregates in Concrete

The number of waste tyres is on the increase, because of the growing use of transport vehicles. Almost one trillion waste tyres are generated in the world annually. Established methods of disposal, recycling and re-use of waste tyres have failed to keep pace with generation, proven to be ineffective, cost-intensive and in some cases environmentally unsustainable. This study aims to investigate the effects of utilizing crumbs from discarded rubber as a partial replacement for coarse aggregates in concrete. Rubber crumbs of 10 – 20mm nominal size were produced manually from waste tyres. The rubber crumbs were used to replace 10%, 20% and 30% of coarse aggregates in design concrete of 20N/mm2 target compressive strength. The effects of this material on the slump, water absorption and compressive strength of concrete were examined. The inclusion of rubber crumbs resulted in a decline in the slump of concrete up to 10% relative to the control specimen. Water absorption increased marginally at 10% replacement compared to the control specimen and recorded a maximum value of 0.77% with 30% replacement after 28 days of curing. The compressive strength of the concrete was negatively affected by the rubber crumbs. The maximum value of 13.9N/mm2 was attained at 10% replacement after 28 days of curing. Rubberized concrete with 10% replacement of coarse aggregates can be used for non-structural concrete members such as roof slabs, non–load–bearing partition walls, and roadside barriers. Chemical treatment of rubber crumbs to improve surface adhesion properties should be encouraged.

Influence of sustainable waste granite, marble and nano-alumina additives on ordinary concretes: a physical, structural, and radiological study

This study investigates the individual and combined effects of enhancing the radiation shielding properties of waste concrete using the optimal mix design of two waste material powders of different compositions. Marble (MD) and granite (GD) waste dust were individually utilized as partial replacements for cement at a replacement ratio of 6%. Furthermore, two additional mixes were prepared by incorporating 1% by cement weight of nano alumina (NA) to enhance the microstructure of the studied waste concrete. The MGA-concrete was analyzed using X-ray Fluorescence, Energy dispersive X-ray, X-ray diffraction analysis, transmission electron microscopy, and scanning electron microscope techniques. The radiation shielding assets of the examined Concrete samples, such as the linear attenuation coefficient (μ), half value layer (H1/2), tenth value layer (T1/10), and fast neutron removal cross-section were evaluated using the MCS5 Monte Carlo simulation algorithm and Phy-X software. The results showed that the linear attenuation for the GMN-concretes’ order is CO < MD < GD < NA < MD + NA < GD + NA. The GD + Na concrete sample presents the best neutron performance. The studied GMN-concrete samples provide the best protection against γ-rays and fast neutrons. Lastly, the excellent performance of the mixes of waste Granite, Marble, and Nano-Alumina on ordinary would pave the way for their employment as radiation shielding in various nuclear and medical facilities.

Green cement production using sludge from wastewater treatment plants

This study explores the potential of reusing sludge from wastewater treatment plants (WWTPs) as a valuable resource. By calcining the sludge, the resulting ashes are incorporated into cement, leading to the production of eco-friendly or green cement. This method offers a sustainable solution for managing solid waste generated by WWTPs, particularly in Algeria, where waste disposal poses significant environmental challenges. The research focused on evaluating the performance of the green cement by examining the development of mechanical properties, such as compressive strength and flexural strength, over time. The results demonstrate the effectiveness of the proposed valorization process for the sludge studied in this context. Additionally, this approach contributes to reducing the carbon emissions and energy consumption associated with conventional cement production. The incorporation of sludge ash as a partial replacement for clinker also highlights the potential for resource conservation and cost reduction in the construction industry. Overall, this research not only addresses waste management issues but also opens the door for further innovation in the use of alternative materials in cement production. Future studies could explore the optimization of sludge pre-treatment and the long-term environmental benefits of large-scale implementation.

Effects of palm oil fuel ash and crumb rubber on mechanical and thermal properties of sustainable engineered cementitious composites

The construction sector using natural sand causes rapid depletion and environmental harm, including erosion, biodiversity loss, and aquatic habitat destruction. To address these challenges and advance sustainability, this study systematically investigated the behaviour of engineered cementitious composites (ECC) incorporating 10–30 % ground palm oil fuel ash (GPOFA) and crumb rubber (CR) as a fine aggregate substitution. Two different sizes of GPOFA, P600 (in the range of 300 μm–600 μm) and P300 (less than 300 μm), were utilized to substitute the fine aggregate in the mix. Dry density, workability, thermal conductivity, modulus of elasticity, tensile strength and strain, compressive strength, flexural strength, and ultrasonic pulse velocity (UPV) were investigated. Furthermore, the microstructures and mineralogical compositions of the selected ECC samples were also examined. The results indicate that increasing GPOFA and CR content reduced ECC's flowability and density. Incorporating GPOFA reduced the compressive strength by 23 % for P600, 12 % for P300, and 74 % for CR, for 30 % substitution at 28 days. Both substitutions reduced the modulus of elasticity and UPV of ECC due to reduced packing efficiency and increased porosity. Increasing GPOFA improved the first cracking load slightly but decreased ultimate flexural strength, whereas CR significantly reduced both. In addition, tensile strain and strength dropped more significantly for ECC with CR compared to ECC with GPOFA. ECC with CR recorded the highest shrinkage and the lowest thermal conductivity (0.66W/mK). Overall, P600 outperformed P300, and CR showed the lowest performance in ECC across all parameters studied. This study highlights that partial replacement of silica sand with GPOFA could produce greener ECC with acceptable mechanical properties, while CR effectively reduces the thermal conductivity of ECC. Integrating GPOFA and CR adds significant value to these wastes while simultaneously providing a sustainable solution for waste disposal.

Stochastic dynamics mass spectrometric and Fourier transform infrared spectroscopic structural analyses of composite biodegradable plastics

&lt;p&gt;The (partial) replacement of synthetic polymers with bioplastics is due to increased production of conventional packaging plastics causing for severe environmental pollution with plastics waste. The bioplastics, however, represent complex mixtures of known and unknown (bio)polymers, fillers, plasticizers, stabilizers, flame retardant, pigments, antioxidants, hydrophobic polymers such as poly(lactic acid), polyethylene, polyesters, glycol, or poly(butylene succinate), and little is known of their chemical safety for both the environment and the human health. Polymerization reactions of bioplastics can produce no intentionally added chemicals to the bulk material, which could be toxic, as well. When polymers are used to food packing, then the latter chemicals could also migrate from the polymer to food. This fact compromises the safety for consumers, as well. The scarce data on chemical safety of bioplastics makes a gap in knowledge of their toxicity to humans and environment. Thus, development of exact analytical protocols for determining chemicals of bioplastics in environmental and food samples as well as packing polymers can only provide warrant for reliable conclusive evidence of their safety for both the human health and the environment. The task is compulsory according to legislation Directives valid to environmental protection, food control, and assessment of the risk to human health. The quantitative and structural determination of analytes is primary research task of analysis of polymers. The methods of mass spectrometry are fruitfully used for these purposes. Methodological development of exact analytical mass spectrometric tools for reliable structural analysis of bioplastics only guarantees their safety, efficacy, and quality to both humans and environment. This study, first, highlights innovative stochastic dynamics equations processing exactly mass spectrometric measurands and, thus, producing exact analyte quantification and 3D molecular and electronic structural analyses. There are determined synthetic polymers such as poly(ethylenglycol), poly(propylene glycol), and polyisoprene as well as biopolymers in bags for foodstuffs made from renewable cellulose and starch, and containing, in total within the 20,416–17,495 chemicals per sample of the composite biopolymers. Advantages of complementary employment in mass spectrometric methods and Fourier transform infrared spectroscopy is highlighted. The study utilizes ultra-high resolution electrospray ionization mass spectrometric and Fourier transform infrared spectroscopic data on biodegradable plastics bags for foodstuffs; high accuracy quantum chemical static methods, molecular dynamics; and chemometrics. There is achieved method performance |&lt;em&gt;r&lt;/em&gt;| = 0.99981 determining poly(propylene glycol) in bag for foodstuff containing 20,416 species and using stochastic dynamics mass spectrometric formulas. The results highlight their great capability and applicability to the analytical science as well as relevance to both the fundamental research and to the industry.&lt;/p&gt;

Microstructure evolution and catalytic activity of AlCo1−xFeNiTiMox high entropy alloys fabricated by powder metallurgy route

This investigation presents the synthesis of equiatomic and non-equiatomic AlCo1−xFeNiTiMox (x = 0, 0.1, 0.25 and 1.0) high entropy alloys fabricated by mechanical alloying. Mo partially replaced Co. Classic thermodynamic calculations, such as mixing enthalpy (ΔHmix), configurational entropy (ΔSmix), the atomic size difference (δ), entropy to enthalpy ratio (Ω), electronegativity difference (△χ), and valence electron concentration (VEC) were used. Considering δ, Ω and VEC parameters, a BCC solid solution and an intermetallic phase can be predicted due to the partial replacement of Co by Mo. X-ray and electron diffraction of equiatomic HEA without Mo content revealed that after 35 h of milling, a Fe-type BCC lattice phase was formed in the alloy and two L21 phases, in addition to a minimal amount of FCC phase. As the Mo content increased, the Fe-type BCC phase was steadily replaced by the Mo-type BCC phase and the Fe-type FCC phase, and two L21 phases were also developed. When the 5 at% Mo-containing (x = 0.25) alloy was further milled for 80 h, the amount of phases remained almost the same; only the grain size was strongly reduced. The influence of the Mo addition on the properties of studied alloys was also confirmed in the decolourisation of Rhodamine B using a modified photo-Fenton process. The decolourisation efficiency within 20 min was 72% for AlCoFeNiTi and 87% for AlCo0.75FeNiTiMo0.25 using UV light with 365 nm wavelength.

Effect of partial replacement of whole milk khoa with groundnut (Arachis hypogaea) and sunflower seeds (Helianthus annuus) milk on biochemical and functional properties

Effect of partial replacement of whole milk khoa with groundnut (Arachis hypogaea) and sunflower seeds (Helianthus annuus) milk on biochemical and functional properties

Valorization of coffee cherry waste ash as a sustainable construction material

This study explores the potential of treated coffee cherry waste (T-CCW) as a partial replacement of cement in mortar. T-CCW was characterized and incorporated into pastes and mortars at 5 %–25 % cement replacement. The main objectives were to examine the fresh and hardened properties, hydration, and environmental assessment. Results showed that the high specific surface area and porous structure of T-CCW particles increased water demand and accelerated setting times. T-CCW incorporation of up to 15 % enhanced compressive strength at all curing ages due to improved hydration and limited pozzolanic reactions. Ultrasonic pulse velocity indicated good homogeneity and compactness in T-CCW blended mortars. Microstructural analysis revealed that T-CCW enhanced cement hydration, leading to a denser matrix. Environmental analysis showed a reduced embodied carbon and cement intensity index compared to the control mix. Overall, the optimal performance was observed at 15 % T-CCW replacement, significantly improving engineering properties and environmental impact. Further, the fishbone diagram addresses various factors to optimize the use of T-CCW as a cementitious composite. These findings demonstrate the potential of T-CCW as a sustainable construction material, offering a promising pathway towards environmentally friendly and resource-efficient building practices while addressing waste management in the coffee industry.

Pickering emulsions based on ovalbumin‐ferulic acid‐sodium alginate supramolecular hydrogels: application to cookies replacing margarine

SummaryMargarine contains trans fatty acids, which have been linked to adverse effects on human health. It is therefore of the utmost importance to develop superior margarine substitutes for use in baked foods. The protein‐polyphenol‐polysaccharide ternary supramolecular system displays remarkable stability and can be utilised in the formulation of emulsions for partial margarine replacement. The aim of this study was to examine the stability of an ovalbumin (OVA)‐ferulic acid (FA)‐sodium alginate (SA) ternary supramolecular emulsion with varying water‐to‐oil ratios. The emulsion was evaluated for its potential as a substitute for margarine in cookies. The findings revealed that the specific emulsion instability of the system initially increased and subsequently decreased with an increase in corn oil content, reaching an optimal point of stability and dispersibility at a water‐to‐oil ratio of 5:11. As the emulsion was incorporated into the cookie dough at levels ranging from 0% to 100% margarine, the viscoelasticity of the dough was enhanced and the hardness was reduced. As the emulsion content increased in place of margarine, the cookies exhibited visible cracks on the surface, accompanied by an increase in hardness, baking loss rate and a notable change in colour. The cookies demonstrated the optimal quality when the emulsion content was 40%.

Performance, cost, and ecological assessment of fiber-reinforced high-performance mortar incorporating pumice powder and ground granulated blast furnace slag as partial cement replacement

The production of cement and concrete is a significant source of greenhouse gas emissions. Hence, recent governmental regulations have brought the attention of industry and academia to the environmental impact of these materials. Recognizing the pressing need to address the environmental footprint of the widely used construction materials, there is a growing focus on strategic initiatives that involve incorporating alternative waste materials to partially substitute ordinary Portland cement (OPC). It is also noteworthy that high-performance concrete and mortar emits significantly less CO2 per unit of strength. Therefore, this study aims to develop high-strength mortar mixes incorporating pumice powder (PP) and ground granulated blast-furnace slag (GGBS) as substitutes for OPC. To this end, nine different mixes, with varying levels of OPC replacement ranging from 0% to 60%, were produced. These mixes underwent a comprehensive experimental evaluation to assess their physical, mechanical, and durability properties. Scanning electron microscopy analyses were conducted to examine the microstructural characteristics of the mixes as well. Furthermore, the embodied energy, embodied carbon, and cost of the prepared mixes were calculated. The experimental findings suggest that high-strength mortar, with a compressive strength varying between 64 and 82 MPa at 28 days of curing, can be successfully produced with reduced embodied carbon and embodied energy compared to conventional mortar mix while maintaining a comparable cost.

Modelling of Restrained Shrinkage Stresses in Mortar using Artificial Neural Networks

Accurate prediction of tensile stresses in repair mortars is vital for the long-term durability of rehabilitated concrete structures. Existing analytical models are based on the material property theory and often struggle to capture the intricate and non-linear behavior exhibited by different mix types used in concrete. To address the limitation of existing models, neural networks were employed as a modelling approach for more robust and versatile predictions. The data used in developing the models was obtained from laboratory experiments. The input variables to the ANN model included: water content, cement, silica fume, superplasticizer, admixture, and age. Three distinct ANN-based models were developed based on: ordinary Portland cement, 10% silica fume as a partial replacement of cement and a combination of the two binder types. These models were evaluated using four performance metrics: coefficient of determination (R2), root mean square error (RMSE), mean absolute error (MAE), and mean absolute percentage error (MAPE). When mortars with ordinary Portland cement was used as a binder, the R2, MAE, MAPE, and RMSE were 99.74%, 0.0808, 0.0397, and 0.0138, respectively. For mortars with 10% silica fume, the ANN model predicted restrained shrinkage stresses in mortars with R2, MAE, MAPE, and RMSE values of 99.25%, 0.0090, 0.0731, and 0.3161, respectively. When both binders were used, the R2, MAE, MAPE, and RMSE were 99.77%, 0.0093, 0.0804, and 0.1775, respectively. The application of neural networks for predicting restrained shrinkage stresses in repair mortars outperforms conventional models with enhanced accuracy and reliability. The developed ANN models serve as powerful tools for assessing and optimizing the performance of repair mortars, enabling more efficient and precise design strategies in concrete repair.

Fracture characteristics of SMA mixtures with hydrated lime through the semi-circular bending approach

Stone Mastic Asphalt (SMA) is a composite mixture made up of high-quality crushed stone, fine aggregates, an asphalt binder, and a significant percentage of mineral filler in contrast to conventional mixtures. Renowned for its durability and rolling resistance, it is predominantly employed as a surface “wearing” course on main roads subjected to heavy traffic, but it can also be used as a binder course under specific project requirements. In this study, we investigated the effect of hydrated lime as a partial replacement of limestone filler at various concentrations on the mechanical and cracking resistance characteristics of 10-mm SMA mixtures. The semi-circular bending (SCB) test, which is pivotal for understanding the cracking mechanism was used to assess the mixtures performance-related response to this distress type. The mixture cores were produced with granite aggregates, limestone filler as natural filler, hydrated lime as natural filler replacement, and a 30/45 penetration asphalt type. Mixtures containing 1.1 %, 2.2 %, and 3.4 % of hydrated lime by weight of aggregates were evaluated, in addition to a control mixture without hydrated lime. The factors considered for comparing the mixtures included: load and deformation curves, stiffness, fracture toughness, fracture energy, and flexibility index of the mixtures. The experimental program also comprised a set of various test temperatures (0°C, 10°C, and 20°C) to better understand the cracking mechanism. Experimental results indicated a significant performance-dependency on the HL concentration and the test temperature. Precisely, it was found that the mixture with the highest hydrated lime content (3.4 %) exhibited the best cracking performance at 0°C and 20°C, making it a suitable filler replacement concentration. However, at 10°C, the mixture containing 2.2 % hydrated lime showed the most consistent performance overall, suggesting and important improvement in asphalt mixtures’ cracking resistance. Overall, these findings obtained from the SCB test approach substantiate the potential benefit of hydrated lime filler replacement in optimizing the cracking performance and durability of SMA mixtures under varying temperature conditions and loading regimes.

The influence of sugarcane bagasse ash on the microstructure of autoclaved cementitious material: Comparative study with amorphous and crystalline silica

This study aimed to investigate the effects of a partial replacement (25 wt%) of Portland cement with sugarcane bagasse ash (SCBA) on the microstructure of cement pastes. The effects were compared with those of pastes containing amorphous (silica fume) or crystalline (crushed quartz) silica. Two curing methods were used for the pastes: conventional curing (25 °C and RH > 95%) and autoclave curing (220 °C under 2.1 MPa for 8 h). The microstructure of the pastes was characterized by XRD, SEM, FTIR, and the hardness and elastic modulus of their C–S–H regions. The results showed that the pastes cured at room temperature exhibited similar microstructure development, showing little or no reaction, even though silica fume is a highly reactive pozzolanic material. Differently, the hardness of the pastes containing silica fume, SBCA and crushed quartz replacement for cement increased approximately threefold after autoclave curing, while, in contrast, the reference sample, no cement replacement, showed no improvement. This is attributed to the formation of tobermorite and xonotlite. The presence of Al in the SCBA allowed the formation of tobermorite under the autoclave curing conditions (220 °C, 2.1 MPa for 8 h), and in this case, the SCBA exhibited behavior between silica fume and fine quartz.

CHAM-CLAS: A Certificateless Aggregate Signature Scheme with Chameleon Hashing-Based Identity Authentication for VANETs

Vehicular ad hoc networks (VANETs), which are the backbone of intelligent transportation systems (ITSs), facilitate critical data exchanges between vehicles. This necessitates secure transmission, which requires guarantees of message availability, integrity, source authenticity, and user privacy. Moreover, the traceability of network participants is essential as it deters malicious actors and allows lawful authorities to identify message senders for accountability. This introduces a challenge: balancing privacy with traceability. Conditional privacy-preserving authentication (CPPA) schemes are designed to mitigate this conflict. CPPA schemes utilize cryptographic protocols, including certificate-based schemes, group signatures, identity-based schemes, and certificateless schemes. Due to the critical time constraints in VANETs, efficient batch verification techniques are crucial. Combining certificateless schemes with batch verification leads to certificateless aggregate signature (CLAS) schemes. In this paper, cryptanalysis of Xiong’s CLAS scheme revealed its vulnerabilities to partial key replacement and identity replacement attacks, alongside mathematical errors in the batch verification process. Our proposed CLAS scheme remedies these issues by incorporating an identity authentication module that leverages chameleon hashing within elliptic curve cryptography (CHAM-CLAS). The signature and verification modules are also redesigned to address the identified vulnerabilities in Xiong’s scheme. Additionally, we implemented the small exponents test within the batch verification module to achieve Type III security. While this enhances security, it introduces a slight performance trade-off. Our scheme has been subjected to formal security and performance analyses to ensure robustness.

Enhancing Pan Bread Quality: Nutritional and Rheological Benefits of Partial Wheat Flour Replacement with Dahlia Tuber Powder (Dahlia pinnata L.)

Enhancing Pan Bread Quality: Nutritional and Rheological Benefits of Partial Wheat Flour Replacement with Dahlia Tuber Powder (Dahlia pinnata L.)

Cutting the cost to combust methane by embellishing the Co-O-Cu interaction in Cu-incorporated Co3O4-based nanocatalysts

Ingredient control brings huge promise for fabricating high-performance Co3O4-based nanomaterials. Herein, for steering the microstructure and properties of Co3O4 system, copper components were incorporated into Co3O4 through a facile coprecipitation ploy taking n-butylamine as the precipitant. At fitting Cu-addition level, dual Co-O-Cu interactions were established by sharing oxygen species, which was based on the partial replacement of Co2+ by Cu2+ in Co3O4 lattice and creation of hetero-interfaces between surface dispersed CuO and Co3O4. Resultly, CH4 combustion efficiency on tailored catalysts was elevated by lessened crystalline sizes, higher dislocation density, preferable capability towards reduction, more abundant Lewis acidic sites, larger surface concentration of Co3+ sites, and the easy regeneration of active surface lattice oxygen contributed from richer O-vacancies. The above optimal attributes-induced supreme activity was accomplished on 0.4Cu-Co3O4 (molar ratio at 0.4), who was revealed to follow MvK CH4 combustion mechanistic model, and to manifest a decent long-term durability in anhydrous condition. Besides, results underscored that Cu-addition presented tiny contribution for water-resistance.

Long-term potato response to different irrigation scheduling methods using saline water in an arid environment

Crops’ water requirement is generally higher than the annual average precipitation in arid environments characterized by scarce freshwater resources. While using saline water for irrigation can help sustain agriculture in water-stressed regions, several challenges arises concerning productivity and soil salinization. However, adoption of efficient irrigation techniques such as drip irrigation, irrigation scheduling, and deficit irrigation can help optimize water productivity and mitigate salinity problems in irrigated agriculture. In southern Tunisia, potato is considered among the main cultivated horticultural crops due to its high economic value while it is considered as a crop sensitive to salinity. This crop (cv. Spunta) was the subject of long-term studies (2002–2020) conducted during the fall period in the arid region of Médenine. The crop response to full and deficit irrigation with saline water was assessed for several seasons under contrasting climatic conditions. Scheduling using the soil water balance (SWB) method consisted of the total and/or partial replacement of accumulated crop evapotranspiration (ETc), as derived from climatic data and crop coefficients. The impact of decreasing amounts of irrigation waters on crop yield and soil salinity with waters having a salinity ranging between 3 and 7 dS m−1 was evaluated. Results showed improvements in yield (30% to 37%) obtained with the SWB strategy under actual farming conditions, supporting the use of this strategy for irrigation. Appropriate scheduling also seems to be a key element in saving water (15%–22%) and in reducing risks of soil salinization. In the dry environment of southern Tunisia, optimum supply seems to correspond to a replacement of 100% to approximately 70%–80% of ETc. Applying such irrigation levels resulted in a lower salinity buildup in the root zone and higher crop water productivity. Natural salt leaching seems to be more effective under a more humid soil profile. Yield decreases and soil salinity increases almost linearly (r2 = 0.60) with decreasing irrigation water amounts. Future work should focus on the integration of management practices when using saline water. Investigating the relationship and interaction between irrigation amounts, cultivar, fertilizer supply, and salt leaching will help in resolving productivity and environmental issues.

Eco-Sustainable Cement: Natural Volcanic Tuffs’ Impact on Concrete Strength and Durability

This study underscores the potential of utilizing natural volcanic tuffs (NVTs) as supplementary cementitious materials (SCMs) in alignment with global sustainability efforts aimed at mitigating the cement industry’s negative impacts on both the economy and the environment. Experimental investigations were conducted on concrete mixtures containing 10%, 20%, 30%, 40%, and 50% NVT as partial cement replacements to assess their influence on concrete’s mechanical and microstructural properties. Based on the findings, concrete samples with 10% NVT replacements exhibited increased flexural and compressive strengths of 35.6% and 5.6%, respectively, compared with ordinary concrete after 28 days. The depth of water penetration in the concrete samples was significantly reduced by the inclusion of NVT, with a maximum reduction of 56.5%. Microstructural analysis using scanning electron microscopy (SEM) revealed enhanced densification of the concrete microstructures, attributed to the high pozzolanic activity of NVT use in cement-based composites. Analysis of variance (ANOVA) revealed statistically significant relationships between NVT content and both the compressive and flexural strengths of the concrete samples. In conclusion, substituting 10% cement with NVT not only enhances the mechanical properties of concrete but also decreases the energy demand for cement production and reduces carbon dioxide (CO2) emissions, thus contributing to more sustainable construction practices.

Potato and dairy industry side streams as feedstock for fungal and plant cell cultures

Utilization of industrial side streams as nutrient source for cellular agriculture is a promising option to improve the sustainability of the production processes. The aim of the study was to evaluate usability of two liquid food industry side streams, potato cell fluid and acid whey, as nutrient source for production of food ingredients with plant cell cultures (arctic bramble (Rubus arcticus L.) and tobacco BY-2 (Nicotiana tabacum L.)) and filamentous fungi (Paecilomyces variotii, Rhizopus oligosporus and Trichoderma reesei). The side streams were found to contain various sugars and other potential nutrients suitable for the studied organisms. The side streams were used as a sole nutrient source (fungi) or as a replacement of selected nutrients in the growth media (fungi and plant cells) in flask scale cultivations. Acid whey was successfully used as a growth medium for filamentous fungi, but it inhibited plant cell growth presumably due to high organic acid content (14 g/l). Potato side stream was found suitable as a fungal and plant cell growth media supplement, and it was used together with glucose for filamentous fungi, or as a partial replacer of macronutrients for plant cells, in bioreactor cultivations yielding high fungal (up to 36 g/l dry weight) and good plant cell (9.5 g/l dry weight) biomass production. Analyses of the produced biomasses revealed good nutritional value in terms of amino acid (17–27 % of dry matter) and dietary fiber (23–30 % of dry matter) contents, giving good premises for utilization in human nutrition.

Immobilization of radioactive borate liquid waste using calcined laterite–phosphoric acid–Fe3O4-based geopolymer waste forms

In this study, the feasibility of preparing a calcined laterite–phosphoric acid–Fe3O4-based geopolymer is investigated and its application for immobilizing radioactive borate liquid waste (RBLW) is explored. The addition of Fe3O4 enhances the compressive strength of the geopolymer and mitigates the retardation effects on the geopolymer caused by RBLW. Reactions between Fe3O4 and H3PO4 not only promote the geopolymerization process by generating heat and forming additional geopolymer gel, but also produce amorphous iron–phosphorus phases, contributing to higher compressive strength of the waste forms. Moreover, partial replacement of [AlO4] tetrahedra with [FeO6] octahedra creates stable –Fe–O–P–O–Al–O–Si– network structures. The geopolymer waste forms exhibit remarkable leaching resistance after Fe3O4 addition owing to the reduced open porosity, leading to radionuclide immobilization through physical encapsulation more efficiently. Furthermore, residual Fe3O4 may contribute to Co2+ immobilization through magnetic adsorption. Overall, the calcined laterite–phosphoric acid–Fe3O4-based geopolymer waste forms exhibit excellent performance in immobilizing RBLW, offering a new strategy for RBLW treatment.