Search Results (587)

Conventional separation methods often prove ineffective for complex, refractory high-phosphorus iron ores. Recent advances propose a coal-based direct reduction dephosphorization-magnetic separation process, achieving significant dephosphorization efficiency. This review systematically analyzes phosphorus occurrence states in high-phosphorus oolitic iron ores across global deposits, particularly within iron minerals. We categorize contemporary research and elucidate dephosphorization mechanisms during coal-based direct reduction. Key factors influencing iron mineral phase transformation, iron enrichment, and phosphorus removal are comprehensively evaluated. Phosphorus primarily exists as apatite and collophane gangue m horization agents function by: (1) inhibiting phosphorus-bearing mineral reactions or binding phosphorus into soluble salts to prevent incorporation into metallic iron; (2) enhancing iron oxide reduction and coal gasification; (3) disrupting oolitic structures, promoting metallic iron particle growth, and improving the intergrowth relationship between metallic iron and gangue. Iron mineral phase transformations follow the sequence: Fe₂O₃ → Fe₃O₄ → FeO (FeAl₂O₄, Fe₂SiO₄) → Fe. Critical parameters for effective dephosphorization under non-reductive phosphorus conditions include reduction temperature, duration, reductant/dephosphorization agent types/dosages. Future research should focus on: (1) investigating phosphorus forms in iron minerals for targeted ore utilization; (2) reducing dephosphorization agent consumption and developing sustainable alternatives; (3) refining models for metallic iron growth and improving energy efficiency; (4) optimizing reduction atmosphere control; (5) implementing low-carbon emission strategies. Full article

Slope aspect and slope position have an important influence on plant growth by changing the microclimate and soil conditions such as light, temperature, moisture, and nutrients. In this study, 15-year-old Sapindus mukorossi forests with different slope aspects and positions were selected and the differences in tree height and diameter at breast height (DBH), leaf non-structural carbohydrate (NSC) characteristics, and leaf–soil nitrogen (N), phosphorus (P), and potassium (K) stoichiometric characteristics between sunny and shady slopes, and upper, middle, and down slope positions were compared and analyzed. The results show that the tree height and DBH of S. mukorossi were better in the same slope aspect and lower slope position, while in the same slope position, the tree height and diameter at DBH were better on the shady slopes. In the upper slope position, the starch content on the shady slope was significantly higher than that on the sunny slope, and the NSC content was significantly higher than that on the sunny slope. On shady and sunny slopes, S. mukorossi is mainly limited by N. The leaf and soil P content of S. mukorossi on the sunny slope was the highest and significantly higher than that on the upper slope. The coefficient of variation of each index of S. mukorossi on the shady slope and the sunny slope was medium and below. Soil N/P, soil N, soil N/K, soluble sugar/starch, leaf P, leaf K, leaf N, and soil K had strong plasticity under different slope aspects. Therefore, it indicated that the shady slope and down slope were more suitable for S. mukorossi. Full article

Microalgae are considered to be a dual solution for CO₂ fixation and biogas slurry purification due to their high photosynthetic efficiency and strong environmental adaptability. However, their application is constrained by the low solubility of CO₂ in the solution environment, which restricts microalgal growth, resulting in low biomass production and poor slurry purification efficiency. In this study, we developed MgFe layered double hydroxide (LDH) that spontaneously combined with Chlorella pyrenoidosa to help it concentrate CO₂, thereby increasing biomass yield and purification capacity for food waste biogas slurry. The prepared MgFe-LDH exhibited a typical layered structure with a CO₂ adsorption capacity of 4.44 mmol/g. MgFe-LDH and C. pyrenoidosa carried opposite charges, enabling successful self-assembly via electrostatic interaction. Compared with the control, the addition of 200 ppm MgFe-LDH increased C. pyrenoidosa biomass and pigment content by 36.82% and 63.05%, respectively. The removal efficiencies of total nitrogen, total phosphorus, and ammonia nitrogen in the slurry were enhanced by 20.04%, 31.54% and 14.57%, respectively. The addition of LDH effectively alleviated oxidative stress in C. pyrenoidosa and stimulated the secretion of extracellular polymeric substances, thereby enhancing the stress resistance and pollutant adsorption capabilities. These findings provided a new strategy for the industrial application of microalgal technology in CO₂ fixation and wastewater treatment. Full article

Young child formula (YCF) products are important sources of nutrients for children 1–3 years of age. Salt equilibria and protein glycation are two of the crucial aspects affecting nutritional properties and digestive behaviors of YCF, but detailed insights into these two aspects of YCF products remains limited. This study analyzed the distribution of salts and the level of protein glycation in 25 commercial YCF products from the retail market in China. The YCF products were reconstituted (12 g of powder per 100 g of water) and the distribution of calcium and phosphorus between the sedimentable (at 200× g), protein-associated and soluble (10 kDa-permeable) fractions were determined. Blocked lysine and 5-hydroxymethylfurfural were analyzed using reversed-phase high-performance liquid chromatography. Varying proportions of calcium (3.0–39.3%) and phosphorus (1.2–29.8%) were sedimentable for the products. Notable proportions of calcium (28.9–62.7%) and phosphorus (27.4–57.9%) were associated with the proteins. The remainder of the calcium (24.9–41.4%) and phosphorus (34.2–62.1%) were soluble. When expressing the protein-associated calcium as a function of casein, i.e., casein mineralization, large differences (~1.7 fold) were found among products. Variation in blocked lysine (7.4–19.2% of total lysine) and 5-hydroxymethylfurfural contents (3.0–7.0 mg/100 g protein) among products was also observed, suggesting notable differences in heat-load during processing. This study revealed notable variation in salt distribution and protein glycation among the YCF products. These findings underscore the critical need for manufacturers to optimize formulation and processing approaches, e.g., using milk with a low level of casein mineralization and using milk protein sources as concentrated liquid rather than powder to reduce protein glycation, to improve nutritional properties of the products. Full article

The addition of sea buckthorn(Hippophae rhamnoides L.) fruits as well as their extracted juice or, even more interestingly, related by-products into chocolate results in manufacturing an innovative functional food rich in bioactive substances. Thirteen treatments derived from the factorial combination of three types of H. rhamnoides materials (total fruit powder; fruit by-product powder; and fruit juice) and four concentrations (10%, 15%, 20% and 25%), plus an untreated control, were compared in terms of texture, quality, colour, antioxidant, mineral and sensorial properties of white chocolate. The untreated control showed the highest values of most of the texture parameters, as well as of pH, dry matter, soluble solids and colour component ‘L’. The colour component ‘b’ was best influenced by the 10% by-product addition to chocolate, whereas mineral substances, ash and colour component ‘a’ augmented with the increasing concentration of added H. rhamnoides materials. Compared to the untreated control, protein and fat contents in chocolate decreased with the rising added concentration of sea buckthorn fruit juice but showed the opposite trend under the integration of the whole fruit and its by-products. The antioxidant compounds and activity increased from the untreated chocolate to the highest concentration of added sea buckthorn materials. The juice addition to the chocolate best affected vitamin C, total carotenoids, β-carotene and lycopene, whereas the whole fruit integration led to the top levels of flavonoids, polyphenols and antioxidant activity. Potassium and zinc contents decreased from the untreated control to the highest H. rhamnoides material addition, whereas opposite trends were shown by calcium, magnesium, sodium and phosphorus. The integration of H. rhamnoides fruit materials into chocolate presents a valuable strategy to produce innovative health beneficial functional food. Full article

The results from previous environmental studies on the physicochemical properties of bottom sediments from the Odra River estuary (SW Baltic Sea) and their contamination by pharmaceutically active compounds (PhACs) were compiled and analyzed by the use of various statistical methods (Principal Component Analysis, ANOVA/Kruskal–Wallis, Spearman correlation analysis, Partial Least Squares Discriminant Analysis, and Cluster Analysis). These studies included data on 130 PhACs determined in sediment samples collected from 70 sites across the Odra River estuary as well as the site distance to wastewater treatment plant discharge, PhACs’ physicochemical properties (Kd, Kow, pKa, solubility, metabolism), and sales data. Additionally, total organic carbon, total nitrogen, total phosphorus, acid volatile sulfides, clay mineral content, and trace elements such as As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sn, and Zn were analyzed. Clay mineral content and TP were identified as the key physicochemical factors influencing the spatial distribution of PhACs in bottom sediments, exerting a greater impact than the distance of sampling sites from WWTP discharge points. The distribution of PhACs in the estuary was also influenced by the Kd and solubility of the compounds. More soluble pharmaceuticals with low adsorption affinity to sediments were detected more frequently and transported to distant locations, whereas less soluble compounds with high adsorption affinity settled down in bottom sediments near contamination sources. Neither the proportion of a drug excreted unchanged, nor its prescription frequency and sales volume, influenced the spatial distribution of PhACs. In general, Kd may be a useful parameter in the planning of environmental monitoring and tracing migration of PhACs in aquatic environments. Full article

In this study, the effects of composting phase and bulking agent on macronutrient extraction and the chemical, physicochemical, and biological properties of 20 compost teas from poultry waste composting mixtures were evaluated. Phosphorus (P) extraction was more efficient during stabilization after the thermophilic phase; however, water-soluble P declined as composting progressed. K was more amenable to extraction, with yields ranging from 30% to 70%, followed by N (2% to 12%) and P (1% to 7%). Compost tea quality was clearly affected by both the bulking agent and the composting stage. Bulking agents that accelerate the process, such as cotton waste (CW) and Napier grass (NG), contributed to nutrient mineralization, increasing availability in the compost tea but also raising salt contents responsible for phytotoxicity. In contrast, tree trimmings (TT), sawdust (S), and sugarcane bagasse (SCB) showed better results, striking a balance between nutrient availability and salt content. The period between the thermophilic phase and cooling was the most suitable for extraction, providing the greatest contribution of water-soluble nutrients. This study highlights the influence of bulking agents and composting phases on nutrient extraction and phytotoxicity of compost teas and provides new insights into the role of electrical conductivity as a threshold indicator for safe agricultural application. Full article

Ridge and furrow planting is a prevalent drought-resistant cultivation technique in dryland regions. Notably, the effects of this technology on crop grain yield and quality in dryland maize–wheat double-cropping systems remain limited. This study utilized a long-term positioning experiment initiated in 2004, which included five treatments: a permanent ridge and furrow with a border ridge of 133 cm row space (PRFBR); a ridge and furrow created each year with a border ridge of 133 cm row space (EYRFBR); a permanent ridge with a normal ridge of 100 cm row space (PRFNR); a ridge and furrow created each year with a normal ridge of 100 cm row space (EYRFNR), and a conventional flat planting pattern according to the local farmer (CF). The crop grain yield in 2015–2021, as well as the protein and phosphorus (P) and potassium (K) content in maize and wheat grains, and the protein components in winter wheat grains in 2020–2021 were investigated. The results showed that, compared to CF, all four ridge and furrow planting patterns significantly enhanced crop yield in dry and normal years, and the effects varied depending on crop species, with increases of 45.3–97.8% for wheat and 11.0–33.8% increases annually in dry years; and 24.5–51.6% increases for maize and 12.2–37.5% increases annually in the normal years. EYRFBR treatment increased wheat grain P and K content by 24.3% and 13.7%, as well as increasing the total protein, albumin, gliadin, soluble protein, and storage protein content by 9.7%, 22.3%, 9.6%, 14.5%, and 5.6%, whereas PRFNR reduced the glutenin content and glutenin/gliadin ratio in winter wheat grains by 5.1% and 10.9%, respectively. The yield achieved with a permanent ridge and furrow (PRF) surpassed that achieved when the ridge and furrow was created anew each year (EYRF), yet the normal ridge width (NR) outperformed the border ridge width (BR). However, the P, K, protein, and protein component content in wheat grains under EYRF was superior to that under PRF. Comprehensive evaluations through principal component analysis (PCA) and TOPSIS analysis consistently demonstrated that the EYRFBR treatment delivered optimal performance in yield and quality for winter and annual, while PRFNR achieved superior yield for summer maize. Consequently, in dryland maize–wheat double-cropping systems, an EYRFBR planting pattern should be recommended for high-yield and high-quality wheat production; however, the PRFNR planting pattern is more suitable for summer maize production. Full article

Global food systems face growing pressure from population expansion and climate change, making the identification of resilient crops a priority. The nopal cactus (Opuntia spp.) stands out for its capacity to thrive in arid environments and for its cultural and economic importance in Mexico. This study analyzes worldwide research trends and evaluates evidence from Mexico to identify opportunities and strategies for closing production cycles through residue valorization. Scientific output over the past decade shows steady growth and a thematic transition from basic agronomic and compositional studies toward sustainability, bioactive compounds, and circular economy approaches. In the Mexican context, applied studies demonstrate that Opuntia spp. cladodes residues can be transformed into composts with C/N ratios between 12 and 26, improving soil organic matter and nutrient availability. Biofertilizers produced through anaerobic fermentation enhanced phosphorus solubility in alkaline soils, while direct residue incorporation increased carrot and tomato yields up to threefold. Farmers recognize these practices as low-cost and compatible with local systems. Nevertheless, the lack of standardized protocols and scalable models limits widespread adoption. Strengthening research collaboration, policy incentives, and technology transfer could position Mexico as a leader in sustainable Opuntia value chains and advance circular economy practices in smallholder farming systems. Full article

The continued acidification of red soil reduces phosphorus availability and microbial activity, which restricts corn growth. Phosphorus tailings, a waste product from phosphate mining, can neutralize soil acidity and supply controlled-release phosphorus, but their effects on the red soil-corn system remain unclear. A field experiment in Qujing, Yunnan (2023–2024), tested four treatments: CK (standard fertilization), T1 (CK plus phosphorus tailings), T2 (80% of standard fertilizer plus phosphorus tailings), and T3 (80% of standard fertilizer plus phosphorus tailings and organic fertilizer, both applied at 6.0 t·ha⁻¹). Using high-throughput sequencing, redundancy analysis (RDA), and structural equation modeling (SEM), the study evaluated impacts on soil properties, microbial communities, and corn yield and quality. Results showed: (1) Phosphorus tailings reduced soil acidification; T3 raised soil pH in the top 0–10 cm by 0.54–0.9 units compared to CK and increased total, available, and soluble phosphorus in the 0–20 cm layer to 952.82, 28.46, and 2.04 mg/kg, respectively. (2) T3 exhibited the highest microbial diversity (Chao1 and Shannon indices increased by 177.57% and 37.80% versus CK) and a more complex bacterial co-occurrence network (114 edges versus 107 in CK), indicating enhanced breakdown of aromatic compounds. (3) Corn yield under T3 improved by 13.72% over CK, with increases in hundred-grain weight (+6.02%), protein content (+18.04%), and crude fiber (+9.00%). (4) Effective nitrogen, ammonium nitrogen, available phosphorus, and soil conductivity were key factors affecting gcd/phoD phosphorus-reducing bacteria. (5) Phosphorus tailings indirectly increased yield by modifying soil properties and pH, both positively linked to yield, while gcd-carrying bacteria had a modest positive influence. In summary, combining phosphorus tailings with a 20% reduction in chemical fertilizer reduces fertilizer use, recycles mining waste, and boosts corn production in acidic red soil, though further studies are needed to evaluate long-term environmental effects. Full article

Background/Objectives: Vitamin D (VD) is a fat-soluble vitamin essential for bone health, and calcium and phosphorus absorption. Recently, new interesting functions are reported such as neuroprotective activity, regulatory roles in the immune system, and protective effects in cancer patients. However, the lipophilic nature of VD represents a limitation, as it is associated with low solubility and poor absorption; additionally, VD exhibits poor stability. Methods: Two nanoliposomes containing VD, conventional (LP-VD) and conjugated with D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS, LPT-VD), were developed. The physical and chemical stability during the storage and gastrointestinal stability, the dissolution profile, the cytotoxicity and the Caco-2 cellular uptake were investigated. Nanoliposomes were fully characterized determining sizes, PdI, Zeta potential, encapsulation efficiency and recovery and they were lyophilized to improve stability. Subsequently, the freeze-dried liposomes were encapsulated in hard gelatin capsules to mimic an oral dosage form, and they were subjected to dissolution test. Results: LP-VD exhibited an average size of 85.50 ± 5.70 nm, a PdI of 0.24 ± 0.06, and a ZP of −20.90 ± 4.37 mV. LPT-VD showed an average size of 61.70 ± 3.90 nm, a PdI of 0.26 ± 0.02, and a ZP of −9.45 ± 2.99 mV. The EE% values were 95.76 ± 1.26% and 97.54 ± 3.24% for LP-VD and LPT-VD, respectively. Both nanoliposomes solubilized 2 mg/mL of VD and improved both its storage stability and stability in aqueous and gastrointestinal environment. The freeze-dried products guarantee constant chemical-physical parameters for 28 days at 25 °C. VD dissolution profile was improved. Conclusions: Nanoliposomes, in particular LPT-VD, showed the best results in terms of chemical stability, dissolution profile, and Caco-2 cellular uptake, confirming the stabilization, bioenhancer properties and P-gp inhibition capabilities of TPGS. Full article

In this study, the contents of minerals, free amino acids (FAAs), biogenic amines (BAs), γ-aminobutyric acid (GABA), and spermidine (SPD) were analyzed in selected white mold-ripened and blue-veined cheeses, including their spatial distribution between rind and core. Blue-veined cheeses contained higher levels of sodium, calcium, phosphorus, FAAs, and SPD. The BAs content was higher in cheeses produced from raw milk. Compared to the cores, the rinds of the analyzed cheeses contained more calcium (up to 66-fold), phosphate (up to 4.4-fold), zinc (up to 9.9-fold), and GABA (up to 17-fold). In white mold-ripened cheeses, where molds do not grow in the core, the rinds also contained more FAAs (up to 15-fold) and SPD (up to 127-fold). Our results confirm previous observations that the rinds of mold-ripened cheeses contain higher amounts of nutritionally valuable cations that form poorly soluble phosphate salts. To our knowledge, this study provides the first demonstration that the rinds of white mold-ripened cheeses are enriched in GABA and SPD, bioactive compounds associated with beneficial health effects. This highlights the high nutritional value of the outer layers of cheese produced with food-grade molds. Full article

The ecological restoration of tropical islands, such as the Xisha Islands, is critical for sustainable development but is hindered by extreme environmental conditions and nutrient-poor coral sand soils. This study assessed the adaptive strategies of two introduced landscape species, Acacia auriculiformis and Nerium oleander, by comparing their leaf physiological and biochemical traits across three treatments: native coral sand (SS2), coral sand amended with garden soil (SS1), and a garden soil control (GZ). Results revealed differentiated physiological adaptation strategies: N. oleander exhibited a ‘conservative tolerance’ strategy, characterized by maintaining higher levels of soluble proteins and the non-enzymatic antioxidant GSH, whereas A. auriculiformis employed an ‘active defense’ strategy, significantly upregulating its enzymatic antioxidant system (SOD activity increased by up to 58.80% in coral sand compared to the control). Soil amendment was crucial for improving plant performance by fundamentally altering the soil’s physicochemical properties and nutrient status. Specifically, amending coral sand with garden soil (SS1 vs. SS2) resulted in a threefold increase in both soil organic carbon (from 3.81 to 11.63 g kg⁻¹) and water content (from 0.04% to 0.12%), while also increasing available phosphorus by over 50% and reducing the extreme soil alkalinity. This amelioration of the soil environment directly enhanced plant antioxidant capacity and overall growth performance. These findings provide a scientific basis for plant introduction on tropical islands, demonstrating that success depends on matching species-specific adaptive strategies with appropriate soil improvement techniques. Full article

High levels of phosphorus cause eutrophication, leading to water blooms and making the water undesirable in aquatic environments. Surface water pollution by phosphorus (P) is caused by both point and diffuse sources. Despite the recent technological advancements in wastewater phosphorus removal, this element persists in aquatic ecosystems, particularly in sediments, often in non-bioavailable forms (in the case of precipitation by aluminum salts) or within biomass associated with high concentrations of heavy metals, rendering it unsuitable for reuse. In this paper, we review the measures and methods commonly used for reducing or removing bioavailable phosphorus, with a focus on the strategies and methods for direct in situ phosphorus removal or reuse, including the use of microbial biofilms and aquatic macrophytes, natural and constructed wetlands, and biotised (biologically enhanced) solid-phase sorbents or woodchip bioreactors. This paper also highlights the significance of bioavailable phosphorus from both the hydrochemical perspectives, examining phosphorus speciation, solubility, and the geochemical interactions influencing mobility in water and sediments, and the biological perspectives, which consider phosphorus uptake, bioaccumulation in aquatic organisms, and the role of microbial and plant communities in modulating phosphorus cycling. This overview presents sustainable phosphorus management approaches that are key to reducing eutrophication and supporting ecosystem health. Full article

In this study, we optimize the kitchen waste fermentation process by adjusting the fermentation time and temperature to prepare high-efficiency carbon sources to enhance nitrogen and phosphorus removal during sewage treatment. Simulated kitchen waste fermentation experiments were performed, and the impact on the pollutant removal efficiencies was analyzed using a sequence batch reactor (SBR). The results showed that the volatile fatty acid (VFA) concentration peak occurred on the first day of fermentation, the maximum increment was 543.19 mg/L, and the maximum soluble chemical oxygen demand/total nitrogen (COD/TN) ratio was 40.49. However, the highest total nitrogen (TN) removal efficiency was 70.42% on the second day of fermentation. An increase in temperature promoted organic matter release, with the highest soluble COD concentration of 22.69 g/L observed at 45 °C. Further, the maximum VFAs production (935.08–985.13 mg/L) occurred from 25 to 35 °C. In addition, the fermentation products in this temperature range also showed the optimal removal efficiencies for total phosphorus (TP) and TN at 91.50% and 79.63%, respectively. Although 15 °C and 45 °C were beneficial for COD reduction, they were not conducive to nitrogen and phosphorus removal. The energy consumption and the synergistic pollutant removal showed that the optimal fermentation conditions were 2 days at 35 °C. Under these conditions, the kitchen waste-derived carbon source achieved efficient TN and TP removal, as well as COD reduction. Therefore, these conditions provide a feasible solution for the “reduction and sustainability” of kitchen waste. Full article