Fluoride removal from coal mining water using novel polymeric aluminum modified activated carbon prepared through mechanochemical process.

Defluoridation of coal mining water is of great significance for sustainable development of coal industry in western China. A novel one-step mechanochemical method was developed to prepare polymeric aluminum modified powder activated carbon (PAC) for effective fluoride removal from coal mining water. Aluminum was stably loaded on the PAC through facile solid-phase reaction between polymeric aluminum (polyaluminum chloride (PACl) or polyaluminum ferric chloride (PAFC)) and PAC (1:15 W/W). Fluoride adsorption on PACl and PAFC modified PAC (C-PACl and C-PAFC) all reached equilibrium within 5 min, at rate of 2.56 g mg-1 sec-1 and 1.31 g mg-1 sec-1 respectively. Larger increase of binding energy of Al on C-PACl (AlF bond: 76.64 eV and AlFOH bond: 77.70 eV) relative to that of Al on C-PAFC (AlF bond: 76.52 eV) explained higher fluoride uptake capacity of C-PACl. Less chloride was released from C-PACl than that from C-PAFC due to its higher proportion of covalent chlorine and lower proportion of ionic chlorine. The elements mapping and atomic composition proved the stability of Al loaded on the PAC as well as the enrichment of fluoride on both C-PACl and C-PAFC. The Bader charge, formation energy and bond length obtained from DFT computational results explained the fluoride adsorption mechanism further. The carbon emission was 7.73 kg CO2-eq/kg adsorbent prepared through mechanochemical process, which was as low as 1:82.3 to 1:8.07 × 104 compared with the ones prepared by conventional hydrothermal methods.

Natural background levels and driving factors of aluminum in shallow groundwater of an urbanized delta: Insight from eliminating anthropogenic-impacted groundwaters.

Knowledge on natural background levels (NBLs) of aluminum (Al) in groundwater can accurately assess groundwater Al contamination at a regional scale. However, it has received little attention. This study used a combination of preselection and statistic methods consisting of the oxidation capacity and the boxplot iteration methods to evaluate the NBL of shallow groundwater Al in four groundwater units of the Pearl River Delta (PRD) via eliminating anthropogenic-impacted groundwaters and to discuss driving factors controlling high NBLs of Al in groundwater in this area. A total of 280 water samples were collected, and 18 physico-chemical parameters including Redox potential, dissolved oxygen, pH, total dissolved solids, HCO3 -, NH4 +, NO3 -, SO4 2-, Cl-, NO2 -, F-, K+, Na+, Ca2+, Mg2+, Fe, Mn, and Al were analyzed. Results showed that groundwater Al NBLs in groundwater units A-D were 0.11, 0.16, 0.15, and 0.08 mg/L, respectively. The used method in this study is acceptable for the assessment of groundwater Al NBLs in the PRD, because groundwater Al concentrations in various groundwater units in residual datasets were independent of land-use types, but they were opposite in the original datasets. The dissolution of Al-rich minerals in sediments/rocks was the major source for groundwater Al NBLs in the PRD, and the interaction with Al-rich river water was secondary one. The high groundwater Al NBL in groundwater unit B was mainly attributed to the acid precipitation and the organic matter mineralization inducing the release of Al in Quaternary sediments. By contrast, the high groundwater Al NBL in groundwater unit C mainly was ascribed to the release of Al complexes such as fluoroaluminate from rocks/soils into groundwater induced by acid precipitation, but it was limited by the dissolution of Mg minerals (e.g., dolomite) in aquifers. This study provides not only useful groundwater Al NBLs for the evaluation of groundwater Al contamination but also a reference for understanding the natural geochemical factors controlling groundwater Al in urbanized deltas such as the PRD. PRACTITIONER POINTS: The natural background level (NBL) of groundwater aluminum in the Pearl River Delta (PRD) was evaluated. The dissolution of aluminum-rich minerals in sediments/rocks was the major source for groundwater aluminum NBLs in the PRD. The acid precipitation and organic matter mineralization contribute to high groundwater Al NBL in the groundwater unit B. The acid precipitation contributes to high groundwater Al NBL in the groundwater unit C, while dissolution of magnesium minerals limits it.

Pervaporation Dehydration Mechanism and Performance of High-Aluminum ZSM-5 Zeolite Membranes for Organic Solvents.

Membrane-based pervaporation (PV) for organic solvent dehydration is of great significance in the chemical and petrochemical industries. In this work, high-aluminum ZSM-5 zeolite membranes were synthesized by a fluoride-assisted secondary growth on α-alumina tubular supports using mordenite framework inverted (MFI) nanoseeds (~110 nm) and a template-free synthesis solution with a low Si/Al ratio of 10. Characterization by XRD, EDX, and SEM revealed that the prepared membrane was a pure-phase ZSM-5 zeolite membrane with a Si/Al ratio of 3.8 and a thickness of 2.8 µm. Subsequently, two categories of PV performance parameters (i.e., flux versus separation factor and permeance versus selectivity) were used to systematically examine the effects of operating conditions on the PV dehydration performance of different organic solvents (methanol, ethanol, n-propanol, and isopropanol), and their PV mechanisms were explored. Employing permeance and selectivity effectively disentangles the influence of operating conditions on PV performance, thereby elucidating the inherent contribution of membranes to separation performance. The results show that the mass transfer during PV dehydration of organic solvents was mainly dominated by the adsorption-diffusion mechanism. Furthermore, the diffusion of highly polar water and methanol molecules within membrane pores had a strong mutual slowing-down effect, resulting in significantly lower permeance than other binary systems. However, the mass transfer process for water/low-polar organic solvent (ethanol, n-propanol, and isopropanol) mixtures was mainly controlled by competitive adsorption caused by affinity differences. In addition, the high-aluminum ZSM-5 zeolite membrane exhibited superior PV dehydration performance for water/isopropanol mixtures.

Effects of copper, and aluminium in ionic, and nanoparticulate form on growth rate and gene expression of Setaria italica seedlings.

This study aims to determine the effects of copper, copper oxide nanoparticles, aluminium, and aluminium oxide nanoparticles on the growth rate and expression of ACT-1, CDPK, LIP, NFC, P5CR, P5CS, GR, and SiZIP1 genes in five days old seedling of Setaria italica ssp. maxima, cultivated in hydroponic culture. Depending on their concentration (ranging from 0.1 to 1.8 mg L-1), all tested substances had both stimulating and inhibiting effects on the growth rate of the seedlings. Copper and copper oxide-NPs had generally a stimulating effect whereas aluminium and aluminium oxide-NPs at first had a positive effect but in higher concentrations they inhibited the growth. Treating the seedlings with 0.4 mg L-1 of each tested toxicant was mostly stimulating to the expression of the genes and reduced the differences between the transcript levels of the coleoptiles and roots. Increasing concentrations of the tested substances had both stimulating and inhibiting effects on the expression levels of the genes. The highest expression levels were usually noted at concentrations between 0.4 and 1.0 mg/L of each metal and metal nanoparticle, except for SiZIP1, which had the highest transcript amount at 1.6 mg L-1 of Cu2+ and at 0.1-0.8 mg L-1 of CuO-NPs, and LIP and GR from the seedling treated with Al2O3-NPs at concentrations of 0.1 and 1.6 mg L-1, respectively.

Encapsulation of Gemcitabine on Porphyrin Aluminum Metal-Organic Framework by Mechano-Chemistry, Delayed Drug Release and Cytotoxicity to Pancreatic Cancer PANC-1 Cells.

Gemcitabine is a widely used antimetabolite drug of pyrimidine structure, which can exist as a free-base molecular form (Gem). The encapsulated forms of medicinal drugs are of interest for delayed and local drug release. We utilized, for the first time, a novel approach of mechano-chemistry by liquid-assisted grinding (LAG) to encapsulate Gem on a "matrix" of porphyrin aluminum metal-organic framework Al-MOF-TCPPH2 (compound 2). The chemical bonding of Gem to compound 2 was studied by ATR-FTIR spectroscopy and powder XRD. The interaction involves the C=O group of Gem molecules, which indicates the formation of the encapsulation complex in the obtained composite. Further, the delayed release of Gem from the composite was studied to phosphate buffered saline (PBS) at 37 °C using an automated drug dissolution apparatus equipped with an autosampler. The concentration of the released drug was determined by HPLC-UV analysis. The composite shows delayed release of Gem due to the bonded form and constant concentration thereafter, while pure Gem shows quick dissolution in less than 45 min. Delayed release of Gem drug from the composite follows the kinetic pseudo-first-order rate law. Further, for the first time, the mechanism of delayed release of Gem was assessed by the variable stirring speed of drug release media, and kinetic rate constant k was found to decrease when stirring speed is decreased (diffusion control). Finally, the prolonged time scale of toxicity of Gem to pancreatic cancer PANC-1 cells was studied by continuous measurements of proliferation (growth) for 6 days, using the xCELLigence real-time cell analyzer (RTCA), for the composite vs. pure drug, and their differences indicate delayed drug release. Aluminum metal-organic frameworks are new and promising materials for the encapsulation of gemcitabine and related small-molecule antimetabolites for controlled delayed drug release and potential use in drug-eluting implants.

Stepwise extraction of lithium and potassium and recovery of fluoride from aluminum electrolyte wastes through calcification roasting-two-stage leaching.

Aluminum electrolyte is a necessity for aluminum reduction cells; however, its stock is rising every year due to several factors, resulting in the accumulation of solid waste. Currently, it has become a favorable material for the resources of lithium, potassium, and fluoride. In this study, the calcification roasting-two-stage leaching process was introduced to extract lithium and potassium separately from aluminum electrolyte wastes, and the fluoride in the form of CaF2 was recycled. The separation behaviors of lithium and potassium under different conditions were investigated systematically. XRD and SEM-EDS were used to elucidate the phase evolution of the whole process. During calcification roasting-water leaching, the extraction efficiency of potassium was 98.7% under the most suitable roasting parameters, at which the lithium extraction efficiency was 6.6%. The mechanism analysis indicates that CaO combines with fluoride to form CaF2, while Li-containing and K-containing fluorides were transformed into water-insoluble LiAlO2 phase and water-soluble KAlO2 phase, respectively, thereby achieving the separation of two elements by water leaching. In the second acid-leaching stage, the extraction efficiency of lithium was 98.8% from water-leached residue under the most suitable leaching conditions, and CaF2 was obtained with a purity of 98.1%. The present process can provide an environmentally friendly and promising method to recycle aluminum electrolyte wastes and achieve resource utilization.

Turn-on detection of Al3+ ions using quinoline-based tripodal probe: mechanistic investigation and live cell imaging applications.

In this study, an easily synthesizable Schiff base probe TQSB having a quinoline fluorophore is demonstrated as a fluorescent and colorimetric turn-on sensor for Al3+ ions in a semi-aqueous medium (CH3CN/water; 4 : 1; v/v). Absorption, emission and colorimetric studies clearly indicated that TQSB exhibited a high selectivity toward Al3+, as observed from its excellent binding constant (Kb = 3.8 × 106 M-1) and detection limit (7.0 nM) values. TQSB alone was almost non-fluorescent in nature; however, addition of Al3+ induced intense fluorescence at 414 nm most probably due to combined CHEF (chelation-enhanced fluorescence) and restricted PET effects. The sensing mechanism was established via Job's plot, NMR spectroscopy, ESI-mass spectrometry, and density functional theory (DFT) analyses. Furthermore, to evaluate the applied potential of probe TQSB, its sensing ability was studied in real samples such as soil samples and Al3+-containing Digene gastric tablets as well as on low-cost filter paper strips. Fluorescence microscopy imaging experiments further revealed that TQSB can be used as an effective probe to detect intracellular Al3+ in live cells with no cytotoxicity.

Toxicity and biokinetics following pulmonary exposure to aluminium (aluminum): A review.

During the manufacture and use of aluminium (aluminum), inhalation exposure may occur. We reviewed the pulmonary toxicity of this metal including its toxicokinetics. The normal serum/plasma level based on 17 studies was 5.7 ± 7.7 µg Al/L (mean ± SD). The normal urine level based on 15 studies was 7.7 ± 5.3 µg/L. Bodily fluid and tissue levels during occupational exposure are also provided, and the urine level was increased in aluminium welders (43 ± 33 µg/L) based on 7 studies. Some studies demonstrated that aluminium from occupational exposure can remain in the body for years. Excretion pathways include urine and faeces. Toxicity studies were mostly on aluminium flakes, aluminium oxide and aluminium chlorohydrate as well as on mixed exposure, e.g. in aluminium smelters. Endpoints affected by pulmonary aluminium exposure include body weight, lung function, lung fibrosis, pulmonary inflammation and neurotoxicity. In men exposed to aluminium oxide particles (3.2 µm) for two hours, lowest observed adverse effect concentration (LOAEC) was 4 mg Al2O3/m3 (= 2.1 mg Al/m3), based on increased neutrophils in sputum. With the note that a similar but not statistically significant increase was seen during control exposure. In animal studies LOAECs start at 0.3 mg Al/m3. In intratracheal instillation studies, all done with aluminium oxide and mainly nanomaterials, lowest observed adverse effect levels (LOAELs) started at 1.3 mg Al/kg body weight (bw) (except one study with a LOAEL of ∼0.1 mg Al/kg bw). The collected data provide information regarding hazard identification and characterisation of pulmonary exposure to aluminium.

The RAE1-STOP1-GL2-RHD6 module regulates the ALMT1-dependent aluminum resistance in Arabidopsis.

Aluminum (Al) toxicity is one of the major constraints for crop production in acid soils, Al-ACTIVATED MALATE TRANSPORTER1 (ALMT1)-dependent malate exudation from roots is essential for Al resistance in Arabidopsis, in which the C2H2-type transcription factor SENSITIVE TO PROTONRHIZOTOXICITY1 (STOP1) play a critical role. In this study, we reveal that the RAE1-GL2-STOP1-RHD6 protein module regulated the ALMT1-mediated Al resistance. GL2, STOP1 and RHD6 directly target the promoter of ALMT1 to suppress or activate its transcriptional expression, respectively, and mutually influence their action on the promoter of ALMT1 by forming a protein complex. STOP1 mediates the expression of RHD6 and RHD6-regulated root growth inhibition, while GL2 and STOP1 suppress each other's expression at the transcriptional and translational level and regulate Al-inhibited root growth. F-box protein RAE1 degrades RHD6 via the 26S proteasome, leading to suppressed activity of the ALMT1 promoter. RHD6 inhibits the transcriptional expression of RAE1 by directly targeting its promoter. Unlike RHD6, RAE1 promotes the GL2 expression at the protein level and GL2 activates the expression of RAE1 at the transcriptional level by directly targeting its promoter. The study provides insights into the transcriptional regulation of ALMT1, revealing its significance in Al resistance and highlighting the crucial role of the STOP1-associated regulatory networks.

Synthesis and characterisation of calcium-iron-aluminium nanocomposites for electromagnetic radiation shielding application.

Electromagnetic shielding parameters are crucial to investigate unexplored nanoparticles and their nanocomposites. Herein, calcium-iron-aluminium (Ca: Fe: Al) nanocomposites are synthesised using the simple solution combustion technique. The as-synthesised nanocomposites with various doping concentrations of Al nanoparticles are characterised to study the structural and surface parameters and to confirm the successful formation. Further, the procured Ca: Fe: Al nanocomposites along with various doping concentrations are utilised for electromagnetic shielding applications, and various shielding parameters are calculated. It was confirmed that Ca: Fe: Al nanocomposites are suitable for electromagnetic shielding applications.

Latent fingerprint imaging using irradiated novel mixed metal oxides (MXOY, M = Ba, Zn, Al, Ce) nanophosphor.

Latent fingerprint developed at the site of crime is considered as crucial physical evidence in forensic investigation. The mixed metal oxides (MXOY, M = Ba, Zn, Al, Ce) nanophosphor was synthesised by irradiating the precursor solution with 60Co gamma radiation followed by solution combustion method. The structural, morphological, optical characteristics and fingerprint imaging were studied using X-ray diffraction (XRD), scanning electron microscopy, UV-visible spectroscopy and powder dusting method, respectively. The XRD results revealed that the average crystallite size is found to be 30 nm with the estimated bandgap of 3.18 eV. The broadband UV exited luminescence of the phosphors was observed at λMax = 330 nm. The PL spectrum shows three emission bands at 432, 444 and 460 nm that corresponds to blue regions, suggesting that the synthesised nanophosphor is a potential luminous material for latent fingerprinting and luminescent devices.

An aqueous symmetric supercapacitor with wide window and high energy density using redox electrode of Cu-Al-layered double hydroxides and λ-manganese dioxide.

Manganese oxide is a potential agent in the field of energy storage owing to its changeable redox characteristics, high theoretical specific capacitance and valence shells for charge transfer. On the other hand, due to huge surface area, affordability, customisable composition, layered structure and high theoretical specific capacitance, layered double hydroxides, or LDHs, have drawn a lot of interest. This study employs a three-electrode setup to investigate the supercapacitive performance of λ-manganese dioxide/Cu-Al LDH composite at different compositional ratios. To enhance the adhesive and conductivity capabilities, 10% of CNT additive and PVDF binder are added for the composites. Out of all the composites, the one with the greatest weight percentage of λ-manganese dioxide shows the best electrode performance with a superior specific capacitance of 164 F/g at a scan rate of 10 mV/s. Additionally, using a symmetrical two-electrode setup, the best-performing electrode is examined. The result shows an exceptional potential window of 2.7 V in a basic electrolyte, a power density of 4.04 kW/kg at 3 A/g, an energy density of 20.32 Wh/kg at 1 A/g, and a specific capacitance of 37 F/g.

Differences in gas exchange, chlorophyll fluorescence, and modulated reflection of light at 820 nm between two rhododendron cultivars under aluminum stress conditions.

Aluminum (Al) toxicity is an important factor restricting the normal growth of plants in acidic soil. Rhododendron (Ericaceae) can grow relatively well in acidic soil. To uncover the adaptive mechanisms of photosynthesis under Al stress, the influence of Al stress on the photosynthetic activities of Al-sensitive (Baijinpao) and Al-resistant (Kangnaixin) rhododendron cultivars was examined by measuring gas exchange, chlorophyll fluorescence, and the modulated reflection of light at 820 nm. Under Al stress conditions, the net photosynthetic rate and stomatal conductance of the rhododendron leaves decreased, whereas the intercellular CO2 concentration increased. The Al stress treatment damaged the oxygen-evolving complex of the rhododendron seedlings, while also inhibiting electron transport on the photosystem II (PSII) donor side. In addition, the exposure to Al stress restricted the oxidation of plastocyanin (PC) and the photosystem I (PSI) reaction center (P700) and led to the re-reduction of PC+ and P700+. The comparison with Kangnaixin revealed an increase in the PSII connectivity in Baijinpao. Additionally, the donor-side electron transport efficiency was more inhibited and the overall activity of PSII, PSI, and the intersystem electron transport chain decreased more extensively in Baijinpao than in Kangnaixin. On the basis of the study findings, we concluded that Al stress adversely affects photosynthesis in rhododendron seedlings by significantly decreasing the activity of PSII and PSI. Under Al stress, Kangnaixin showed stronger tolerance compared with Baijinpao.

Phenotyping revealed tolerance traits and genotypes for acidity and aluminum toxicity in European Vicia faba L.

Soil acidity is a global issue; soils with pH <4.5 are widespread in Europe. This acidity adversely affects nutrient availability to plants; pH levels <5.0 lead to aluminum (Al3+) toxicity, a significant problem that hinders root growth and nutrient uptake in faba bean (Vicia faba L.) and its symbiotic relationship with Rhizobium. However, little is known about the specific traits and tolerant genotypes among the European faba beans. This study aimed to identify response traits associated with tolerance to root zone acidity and Al3+ toxicity and potentially tolerant genotypes for future breeding efforts. Germplasm survey was conducted using 165 genotypes in a greenhouse aquaponics system. Data on the root and shoot systems were collected. Subsequently, 12 genotypes were selected for further phenotyping in peat medium, where data on physiological and morphological parameters were recorded along with biochemical responses in four selected genotypes. In the germplasm survey, about 30% of genotypes showed tolerance to acidity and approximately 10% exhibited tolerance to Al3+, while 7% showed tolerance to both. The phenotyping experiment indicated diverse morphological and physiological responses among treatments and genotypes. Acid and Al3+ increased proline concentration. Interaction between genotype and environment was observed for ascorbate peroxidase activity, malondialdehyde, and proline concentrations. Genomic markers associated with acidity and acid+Al3+-toxicity tolerances were identified using GWAS analysis. Four faba bean genotypes with varying levels of tolerance to acidity and Al3+ toxicity were identified.

Evaluation of setting kinetics, mechanical strength, ion release, and cytotoxicity of high-strength glass ionomer cement contained elastomeric micelles.

BACKGROUND: Low mechanical properties are the main limitation of glass ionomer cements (GICs). The incorporation of elastomeric micelles is expected to enhance the strength of GICs without detrimentally affecting their physical properties and biocompatibility. This study compared the chemical and mechanical properties, as well as the cytotoxicity, of elastomeric micelles-containing glass ionomer cement (DeltaFil, DT) with commonly used materials, including EQUIA Forte Fil (EF), Fuji IX GP Extra (F9), and Ketac Molar (KT). METHOD: Powder particles of GICs were examined with SEM-EDX. Setting kinetics were assessed using ATR-FTIR. Biaxial flexural strength/modulus and Vickers surface microhardness were measured after immersion in water for 24 h and 4 weeks. The release of F, Al, Sr, and P in water over 8 weeks was analyzed using a fluoride-specific electrode and ICP-OES. The toxicity of the material extract on mouse fibroblasts was also evaluated. RESULTS: High fluoride levels in the powder were detected with EF and F9. DT demonstrated an initial delay followed by a faster acid reaction compared to other cements, suggesting an improved snap set. DT also exhibited superior flexural strength than other materials at both 24 h and 4 weeks but lower surface microhardness (p < 0.05). EF and F9 showed higher release of F, Al, and P than DT and KT. There was no statistically significant difference in fibroblast viability among the tested materials (p > 0.05). CONCLUSIONS: Elastomeric micelles-containing glass ionomer cement (DT) exhibited satisfactory mechanical properties and cytocompatibility compared with other materials. DT could, therefore, potentially be considered an alternative high-strength GIC for load-bearing restorations.

Exogenous silicon induces aluminum tolerance in white clover (Trifolium repens) by reducing aluminum uptake and enhancing organic acid secretion.

Excessive aluminum (Al) in acidic soils is a primary factor that hinders plant growth. The objective of the present study was to investigate the effect and physiological mechanism of exogenous silicon (Si) in alleviating aluminum toxicity. Under hydroponic conditions, 4 mM Al significantly impeded the growth of white clover; however, pretreatments with 1 mM Si mitigated this inhibition, as evidenced by notable changes in growth indicators and physiological parameters. Exogenous silicon notably increased both shoot and root length of white clover and significantly decreased electrolyte leakage (EL) and malondialdehyde (MDA) content compared to aluminum treatments. This positive effect was particularly evident in the roots. Further analysis involving hematoxylin staining, scanning electron microscopy (SEM), and examination of organic acids (OAs) demonstrated that silicon relieved the accumulation of bioactive aluminum and ameliorated damage to root tissues in aluminum-stressed plants. Additionally, energy-dispersive X-ray (EDX) analysis revealed that additional silicon was primarily distributed in the root epidermal and cortical layers, effectively reducing the transport of aluminum and maintaining the balance of exchangeable cations absorption. These findings suggest that gradual silicon deposition in root tissues effectively prevents the absorption of biologically active aluminum, thereby reducing the risk of mineral nutrient deficiencies induced by aluminum stress, promoting organic acids exudation, and compartmentalizing aluminum in the outer layer of root tissues. This mechanism helps white clover alleviate the damage caused by aluminum toxicity.

γ-Aminobutyric acid (GABA) priming alleviates acid-aluminum toxicity to roots of creeping bentgrass via enhancements in antioxidant defense and organic metabolites remodeling.

MAIN CONCLUSION: γ-Aminobutyric acid alleviates acid-aluminum toxicity to roots associated with enhanced antioxidant metabolism as well as accumulation and transportation of citric and malic acids. Aluminum (Al) toxicity has become the main limiting factor for crop growth and development in acidic soils and is further being aggravated worldwide due to continuous industrial pollution. The current study was designed to examine effects of GABA priming on alleviating acid-Al toxicity in terms of root growth, antioxidant defense, citrate and malate metabolisms, and extensive metabolites remodeling in roots under acidic conditions. Thirty-seven-day-old creeping bentgrass (Agrostis stolonifera) plants were used as test materials. Roots priming with or without 0.5 mM GABA for 3 days were cultivated in standard nutrient solution for 15 days as control or subjected to nutrient solution containing 5 mM AlCl3·6H2O for 15 days as acid-Al stress treatment. Roots were sampled for determinations of root characteristics, physiological and biochemical parameters, and metabolomics. GABA priming significantly alleviated acid-Al-induced root growth inhibition and oxidative damage, despite it promoted the accumulation of Al in roots. Analysis of metabolomics showed that GABA priming significantly increased accumulations of organic acids, amino acids, carbohydrates, and other metabolites in roots under acid-Al stress. In addition, GABA priming also significantly up-regulated key genes related to accumulation and transportation of malic and citric acids in roots under acid-Al stress. GABA-regulated metabolites participated in tricarboxylic acid cycle, GABA shunt, antioxidant defense system, and lipid metabolism, which played positive roles in reactive oxygen species scavenging, energy conversion, osmotic adjustment, and Al ion chelation in roots.

Biocompatible and Biodegradable 3D Graphene/Collagen Fiber Hybrids for High-Performance Conductive Networks and Sensors.

Polymer-based flexible conductive materials are crucial for wearable electronics, electronic skin, and other smart materials. However, their development and commercial applications have been hampered by the lack of strain tolerance in the conductive network, poor bonding with polymers, discomfort during wear, and a lack of biocompatibility. This study utilized oil-tanned leather with a natural network structure, high toughness, and high tensile deformation recovery as a structural template. A graphene (Gr) conductive network was then constructed on the collagen network of the leather, with coordination cross-linking between Gr and collagen fibers through aluminum ions (Al3+). A new flexible conductive material (Al-GL) was then constructed. Molecular dynamics simulations and experimental validation revealed the existence of physical adsorption, hydrogen bonding adsorption, and ligand bonding between Al3+, Gr, and collagen fibers. Although we established that the binding sites between Al3+ and collagen fibers were primarily on carboxyl groups (-COOH), the mechanism of chemical bonding between Gr and collagen fibers remains unclear. The Al-GL composite exhibited a high shrinkage temperature (67.4 °C) and low electrical resistance (16.1 kΩ·sq-1), as well as good softness (9.33 mN), biocompatibility, biodegradability (<60 h), and air and moisture permeability. Furthermore, the incorporation of Al3+ resulted in a heightened Gr binding strength on Al-GL, and the resistance remained comparable following 1 h of water washing. The Al-GL sensor prepared by WPU encapsulation not only demonstrated highly sensitive responses to diverse motion signals of the human body but also retained a certain degree of response to external mechanical effects underwater. Additionally, the Al-GL-based triboelectric nanogenerator (Al-GL TENG) exhibited distinct response signals to different materials. The Al-GL prepared by the one-pot method proposed in this study offers a novel approach to combining functional nanofillers and substrate materials, providing a theoretical foundation for collagen fiber-based flexible conductive materials.

Experimental and computational study on morin and its complexes with Mg2+, Mn2+, Zn2+, and Al3+: Coordination and antioxidant properties.

Morin (MRN), an intriguing bioflavonol, has received increasing interest for its antioxidant properties, as have its metal complexes (Mz+-MRN). Understanding their antioxidant behavior is critical to assess their pharmaceutical, nutraceutical potential, and therapeutic impact in the design of advanced antioxidant drugs. To this end, knowing the speciation of different H+-MRN and Mz+-MRN is pivotal to understand and compare their antioxidant ability. In this work, the protonation constant values of MRN under physiological ionic strength and temperature conditions (I = 0.15 mol L-1 and t = 37 °C), determined by UV-vis spectrophotometric titrations, are introduced. Thus, a reliable speciation model on H+-MRN species in aqueous solution is presented, which exhibits five stable forms depending on pH, supplemented by quantum-mechanical calculations useful to determine the proton affinities of each functional group and corresponding deprotonation order. Furthermore, potentiometry and UV-vis spectrophotometry have been exploited to determine the thermodynamic interaction parameters of MRN with different metal cations (Mg2+, Mn2+, Zn2+, Al3+). The antioxidant ability of H+-MRN and Mz+-MRN has been evaluated by the 2,2'-diphenyl-1-benzopyran-4-one (DPPH) method, and the Zn2+-MRN system has proven to afford the most potent antioxidant effect. Ab initio molecular dynamics simulations of Mz+-MRN species at all possible chelation sites and under explicit water solvation allowed for the fine characterization not only of the metal chelation modalities of MRN in explicit water, but also of the role played by the local water environment around the metal cations. Those microscopic patterns reveal to be informative on the different antioxidant capabilities recorded experimentally.

Enhanced removal of nano-oil droplets utilizing polysilicate aluminum ferric (PSAF): Leveraging bridging and non-polar surface advantages.

Hydraulic oil leaks during mechanical maintenance, resulting in flushing wastewater contaminated with dispersed nano-oil droplets. In this study, 75 mg L-1 of polysilicate aluminum ferric (PSAF) was stirred at 350 rpm and the optimal chemical oxygen demand (COD) removal was 71%. The increase of PSAF led to more hydrolysis of Fe, and 1,175 cm-1 hydroxyl bridged with negative oil droplets. At the same molar concentration, PSAF hydrolyzes cationic metals more rapidly than polymeric aluminum chloride (PAC). PSAF forms flocs of smaller complex structures with greater bridging. The Al-O and Si-O peaks occurred at 611 and 1,138 cm-1, indicating the formation of Si-O-Fe and Si-O-Al bonds on the flocs surface. Higher stirring speeds did not change the free energy of the flocs surface γTot, mainly because the decrease in the van der Waals force (γLW) offset the increase of Lewis acid-base force (γAB). Preserving the non-polar surface, in summary, owing to its bridging abilities and affinity for non-polar surfaces, PSAF demonstrates superior efficiency over PAC in capturing and removing oil droplets.