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Environmental Science and Pollution... Mar 2024Groundwater environments are complex, and traditional advanced oxidation technologies mainly based on free radicals have limitations such as poor selectivity and low...
Groundwater environments are complex, and traditional advanced oxidation technologies mainly based on free radicals have limitations such as poor selectivity and low interference resistance, making it difficult to efficiently degrade target pollutants in groundwater. Therefore, we developed a sludge-based biochar-supported FeMg-layered double hydroxide catalyst (BC@FeMg-LDH) for the catalytic degradation of 2, 4-dichlorophenol (2, 4-DCP) using persulfate (PDS) as an oxidant. The removal efficiency of the catalyst exceeded 95%, showing high oxidation activity in a wide pH range while being almost unaffected by reducing substances and ions in the environment. Meanwhile, under neutral conditions, the leaching of metal ions from BC@FeMg-LDH was minimal, thereby eliminating the risk of secondary pollution. According to quenching experiments and electron paramagnetic resonance spectroscopy, the main active species during BC@FeMg-LDH/PDS degradation of 2, 4-DCP is O, indicating a non-radical reaction mechanism dominated by O. Characterization techniques, including X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy, revealed that the carbonyl (C = O) and metal hydroxyl (M-OH) groups on the material surface were the main reactive sites mediating O generation. The O generation mechanism during the reaction involved ketone-like activation of carbonyl groups on the biochar surface and complexation of hydroxyl groups on the material surface with PDS, resulting in the formation of O and further generation of O. O exhibited high selectivity toward electron-rich organic compounds such as 2, 4-DCP and demonstrated strong interference resistance in complex groundwater environments. Therefore, BC@FeMg-LDH holds promising applications for the remediation of organic-contaminated groundwater.
Topics: Hydroxides; Charcoal; Metals; Phenols; Groundwater
PubMed: 38413523
DOI: 10.1007/s11356-024-32456-1 -
Toxics Jan 2024The recovery and recycling of metals that generate toxic ions in the environment is of particular importance, especially when these are tungsten and, in particular,...
The recovery and recycling of metals that generate toxic ions in the environment is of particular importance, especially when these are tungsten and, in particular, thorium. The radioactive element thorium has unexpectedly accessible domestic applications (filaments of light bulbs and electronic tubes, welding electrodes, and working alloys containing aluminum and magnesium), which lead to its appearance in electrical and electronic waste from municipal waste management platforms. The current paper proposes the simultaneous recovery of waste containing tungsten and thorium from welding electrodes. Simultaneous recovery is achieved by applying a hybrid membrane electrolysis technology coupled with nanofiltration. An electrolysis cell with sulphonated polyether-ether-ketone membranes (sPEEK) and a nanofiltration module with chitosan-polypropylene membranes (C-PHF-M) are used to carry out the hybrid process. The analysis of welding electrodes led to a composition of W (tungsten) 89.4%; Th 7.1%; O 2.5%; and Al 1.1%. Thus, the parameters of the electrolysis process were chosen according to the speciation of the three metals suggested by the superimposed Pourbaix diagrams. At a constant potential of 20.0 V and an electrolysis current of 1.0 A, the pH is varied and the possible composition of the solution in the anodic workspace is analyzed. Favorable conditions for both electrolysis and nanofiltration were obtained at pH from 6 to 9, when the soluble tungstate ion, the aluminum hydroxide, and solid thorium dioxide were formed. Through the first nanofiltration, the tungstate ion is obtained in the permeate, and thorium dioxide and aluminum hydroxide in the concentrate. By adding a pH 13 solution over the two precipitates, the aluminum is solubilized as sodium aluminate, which will be found after the second nanofiltration in the permeate, with the thorium dioxide remaining integrally (within an error of ±0.1 ppm) on the C-PHF-M membrane.
PubMed: 38393198
DOI: 10.3390/toxics12020103 -
Heliyon Feb 2024In this study, a simple in-situ preparation method for coating on Mg-Zn alloy in a carbonic acid solution was investigated. The formation of a precursor carbonate layer...
In this study, a simple in-situ preparation method for coating on Mg-Zn alloy in a carbonic acid solution was investigated. The formation of a precursor carbonate layer on the alloy surface was observed. As the soaking time increased, the solution gradually turned alkaline, leading to the transformation of the precursor into a basic carbonate coating with a layered hydroxide structure. The corrosion potential () of the coated samples initially decreased and then increased with increasing the soaking time. After 2 h of soaking, the lowest corrosion potential observed was approximately -1.5105 V. At 12 h, the corrosion potential reached around -1.4645 V, which was comparable to that of the ZK61M magnesium alloy. After 48 h, the corrosion potential was measured to be approximately -1.3507 V.
PubMed: 38371983
DOI: 10.1016/j.heliyon.2024.e25587 -
Polymers Feb 2024Due to high filler loading, clean, commercial, thermoplastic, flame-retardant materials are mechanically unstable when insulating wires and cables. In this study,...
Due to high filler loading, clean, commercial, thermoplastic, flame-retardant materials are mechanically unstable when insulating wires and cables. In this study, composite formulations of linear low-density polyethylene (LLDPE)/ethylene-vinyl acetate (EVA) containing a flame retardant, such as magnesium hydroxide (MH; formula: Mg(OH)) and huntite hydromagnesite (HH; formula: MgCa(CO), Mg(CO)(OH)·3HO), were prepared. The influence of carbon nanotubes (CNTs) and carbon black (CB) on the mechanical properties and flame retardancy of LLDPE/EVA was studied. Three types of CNTs were examined for their compatibility with other materials in clean thermoplastic flame-retardant compositions. The CNTs had the following diameters: 10-15 nm, 40-60 nm, and 60-80 nm. Optimum mechanical flame retardancy and electrical properties were achieved by adding CNTs with an outer diameter of 40-60 nm and a length of fewer than 20 nm. Large-sized CNTs result in poor mechanical characteristics, while smaller-sized CNTs improve the mechanical properties of the composites. CB enhances flame retardancy but deteriorates mechanical properties, particularly elongation at break, in clean, black, thermoplastic, flame-retardant compositions. Obtaining satisfactory compositions that meet both properties, especially formulations passing the V-0 of the UL 94 test with a minimum tensile strength of 9.5 MPa and an elongation at break of 125%, is challenging. When LLDPE was partially substituted with EVA, the limiting oxygen index (LOI) increased. The amount of filler in the formulations determined how it affected flammability. This study also included a reliable method for producing clean, black, thermoplastic, flame-retardant insulating material for wire and cable without sacrificing mechanical properties.
PubMed: 38337306
DOI: 10.3390/polym16030417 -
Journal of Tissue Engineering 2024Neuropathic pain (NP) is a debilitating condition stemming from damage to the somatosensory system frequently caused by nerve injuries or lesions. While existing...
Therapeutic potential of luteolin-loaded poly(lactic-co-glycolic acid)/modified magnesium hydroxide microsphere in functional thermosensitive hydrogel for treating neuropathic pain.
Neuropathic pain (NP) is a debilitating condition stemming from damage to the somatosensory system frequently caused by nerve injuries or lesions. While existing treatments are widely employed, they often lead to side effects and lack specificity. This study aimed to alleviate NP by developing an innovative sustained-release thermosensitive hydrogel system. The system incorporates hyaluronic acid (HA)/Pluronic F127 injectable hydrogel and bupivacaine (Bup, B) in combination with poly(lactic-co-glycolic acid; PLGA)/modified magnesium hydroxide (MH)/luteolin (Lut; PML) microspheres (PML@B/Gel). The PML@B/Gel was designed for localized and prolonged co-delivery of Bup and Lut as an anesthetic and anti-inflammatory agent, respectively. Our studies demonstrated that PML@B/Gel had exceptional biocompatibility, anti-inflammatory, and antioxidant properties. In addition, it exhibited efficient pain relief in in vitro cellular assays. Moreover, this functional hydrogel showed substantial sustained drug release while diminishing microglial activation. Consequently, it effectively mitigated mechanical allodynia and thermal hyperalgesia in in vivo rat models of chronic constriction injury (CCI). Based on our research findings, PML@B/Gel emerges as a promising therapeutic approach for the protracted treatment of NP.
PubMed: 38333057
DOI: 10.1177/20417314231226105 -
Waste Management (New York, N.Y.) Mar 2024The utilization of municipal solid waste incineration residues in alkali-activated granulated ground blast furnace slag (GGBFS) has garnered substantial interest for its...
The utilization of municipal solid waste incineration residues in alkali-activated granulated ground blast furnace slag (GGBFS) has garnered substantial interest for its potential in sustainable solid waste management and achieving a low-carbon footprint. However, incorporating these residues often leads to the deterioration of mechanical properties. This study revealed the role of silica fume (SF) and nano-silica (NS) derived from olivine within a sodium carbonate-activated GGBFS system incorporating air pollution control (APC) residues. The dosage of silica additives and APC residues ranges from 0 - 6 wt% and 0-15 wt%, respectively. The mechanical properties, reaction kinetics, phase composition, microstructure and carbonation resistance of the blended binder were investigated. Results indicated that SF slightly improved the early compressive strength with the formation of C-(A)-S-H gel (Ca/Si = 1.47, Al/Si = 0.23), hemicarboaluminate and hydrotalcite; reactive NS retarded the activation of GGBFS and inhibited the formation of hemicarboaluminate and hydrotalcite, while promoting the formation of C-A-S-H gel (Ca/Si = 1.01, Al/Si = 0.23), resulting in an impressive 80.3 % enhancement in compressive strength. Notably, NS-modified samples exhibited decreased carbonation resistance due to increased porosity and C-(A)-S-H gels that are vulnerable to carbonation. Conversely, 2 % SF addition decreased the diffusion rate of CO, and APC residues improved the carbonation resistance by facilitating the formation of C-(A)-S-H gel with a higher Ca/Si ratio. This study provided an alternative management practice for APC residues with favorable early strength development and offered new insights into using silica additives to enhance waste-combined alkali-activated materials.
Topics: Silicon Dioxide; Aluminum Hydroxide; Air Pollution; Carbonates; Magnesium Hydroxide
PubMed: 38262073
DOI: 10.1016/j.wasman.2024.01.028 -
Tissue Engineering and Regenerative... Feb 2024The skin, a vital organ protecting against microorganisms and dehydration, undergoes structural decline with aging, leading to visible issues such as wrinkles and...
BACKGROUND
The skin, a vital organ protecting against microorganisms and dehydration, undergoes structural decline with aging, leading to visible issues such as wrinkles and sagging. Reduced blood vessels exacerbate vulnerability, hindering optimal cellular function and compromising skin health. Polydioxanone (PDO) biomaterials address aging concerns but produce acidic byproducts, causing inflammation. Inorganic particles and nitric oxide (NO) play crucial roles in inhibiting inflammation and promoting skin regeneration. Stem cell-derived extracellular vesicles (EVs) contribute to intercellular communication, offering the potential to enhance cell functions. The study proposes a method to enhance PDO-based medical devices by incorporating inorganic particles and immobilizing EVs, focusing on facial rejuvenation, anti-inflammatory response, collagen formation, and angiogenesis.
METHOD
PDO composites with inorganic particles such as magnesium hydroxide (MH) and zinc oxide (ZO) were prepared and followed by EV immobilization. Comprehensive characterization included biocompatibility, anti-inflammation, collagen formation ability, and angiogenesis ability.
RESULTS
Bulk-modified PDO composites demonstrated even dispersion of inorganic particles, pH neutralization, and enhanced biocompatibility. EVs immobilized on the composite surface exhibited spherical morphology. Inflammation-related gene expressions decreased, emphasizing anti-inflammatory effects. Collagen-related gene and protein expressions increased, showcasing collagen formation ability. In addition, angiogenic capabilities were notably improved, indicating potential for skin rejuvenation.
CONCLUSION
The study successfully developed and characterized PDO composites with inorganic particles and EVs, demonstrating promising attributes for medical applications. These composites exhibit biocompatibility, anti-inflammatory properties, collagen formation ability, and angiogenic potential, suggesting their utility in skin rejuvenation and tissue engineering. Further research and clinical validation are essential.
Topics: Humans; Rejuvenation; Extracellular Vesicles; Collagen; Anti-Inflammatory Agents; Inflammation
PubMed: 38261265
DOI: 10.1007/s13770-023-00622-0 -
Polymers Jan 2024Polylactic acid (PLA) has attracted much attention in bone tissue engineering due to its good biocompatibility and processability, but it still faces problems such as a...
Polylactic acid (PLA) has attracted much attention in bone tissue engineering due to its good biocompatibility and processability, but it still faces problems such as a slow degradation rate, acidic degradation product, weak biomineralization ability, and poor cell response, which limits its wider application in developing bone scaffolds. In this study, Mg(OH) nanoparticles were employed as a versatile nanofiller for developing PLA/Mg(OH) composite bone scaffolds using fused deposition modeling (FDM) 3D printing technology, and its mechanical, degradation, and biological properties were evaluated. The mechanical tests revealed that a 5 wt% addition of Mg(OH) improved the tensile and compressive strengths of the PLA scaffold by 20.50% and 63.97%, respectively. The soaking experiment in phosphate buffered solution (PBS) revealed that the alkaline degradation products of Mg(OH) neutralized the acidic degradation products of PLA, thus accelerating the degradation of PLA. The weight loss rate of the PLA/20Mg(OH) scaffold (15.40%) was significantly higher than that of PLA (0.15%) on day 28. Meanwhile, the composite scaffolds showed long-term Mg release for more than 28 days. The simulated body fluid (SBF) immersion experiment indicated that Mg(OH) promoted the deposition of apatite and improved the biomineralization of PLA scaffolds. The cell culture of bone marrow mesenchymal stem cells (BMSCs) indicated that adding 5 wt% Mg(OH) effectively improved cell responses, including adhesion, proliferation, and osteogenic differentiation, due to the release of Mg. This study suggests that Mg(OH) can simultaneously address various issues related to polymer scaffolds, including degradation, mechanical properties, and cell interaction, having promising applications in tissue engineering.
PubMed: 38256997
DOI: 10.3390/polym16020198 -
Materials (Basel, Switzerland) Jan 2024Magnesium, as one of the most abundant cations in the human body, plays an important role in both physiological and pathological processes. In this study, it was shown...
Magnesium, as one of the most abundant cations in the human body, plays an important role in both physiological and pathological processes. In this study, it was shown that a promising biomedical material, Mg-substituted hydroxyapatite (Mg-HA), can be synthesized via a fast mechanochemical method. For this method, the nature of magnesium-containing carriers was shown to be important. When using magnesium oxide as a source of magnesium, the partial insertion of magnesium cations into the apatite structure occurs. In contrast, when magnesium hydroxide or monomagnesium phosphate is used, single-phase Mg-HA is formed. Both experimental and theoretical investigations showed that an increase in the Mg content leads to a decrease in the lattice parameters and unit cell volume of Mg-HA. Density functional theory calculations showed the high sensitivity of the lattice parameters to the crystallographic position of the calcium site substituted by magnesium. It was shown experimentally that the insertion of magnesium cations decreases the thermal stability of hydroxyapatite. The thermal decomposition of Mg-HA leads to the formation of a mixture of stoichiometric HA, magnesium oxide, and Mg-substituted tricalcium phosphate phases.
PubMed: 38255584
DOI: 10.3390/ma17020416