Construction of oxime-functionalized PCN-222 based on the directed molecular structure design for recovering uranium from wastewater.

The directed construction of productive adsorbents is essential to avoid damaging human health from the harmful radioactive and toxic U(VI)-containing wastewater. Herein, a sort of Zr-based metal organic framework (MOF) called PCN-222 was synthesized and oxime functionalized based on directed molecular structure design to synthesize an efficient adsorbent with antimicrobial activity, named PCN-222-OM, for recovering U(VI) from wastewater. PCN-222-OM unfolded splendid adsorption capacity (403.4 mg·g-1) at pH = 6.0 because of abundant holey structure and mighty chelation for oxime groups with U(VI) ions. PCN-222-OM also exhibited outstanding selectivity and reusability during the adsorption. The XPS spectra authenticated the -NH and oxime groups which revealed a momentous function. Concurrently, PCN-222-OM also possessed good antimicrobial activity, antibiofouling activity, and environmental safety; adequately decreased detrimental repercussions about bacteria and Halamphora on adsorption capacity; and met non-toxic and non-hazardous requirements for the application. The splendid antimicrobial activity and antibiofouling activity perhaps arose from the Zr6(µ3-O)4(µ3-OH)4(H2O)4(OH)4 clusters and rich functional groups within PCN-222-OM. Originally proposed PCN-222-OM was one potentially propitious material to recover U(VI) in wastewater on account of outstanding adsorption capacity, antimicrobial activity, antibiofouling activity, and environmental safety, meanwhile providing a newfangled conception on the construction of peculiar efficient adsorbent.

A convenient functionalization strategy of polyimide covalent organic frameworks for uranium-containing wastewater treatment and uranium recovery.

The purpose of this research was to design and synthesize an adsorbent based on polyimide covalent organic frameworks (PICOFs) for uranium-containing wastewater treatment and uranium recovery. A modified solvothermal method was innovatively proposed to synthesize PICOFs with high specific surface area (1998.5 m2 g-1) and regular pore structure. Additionally, a convenient functionalization strategy of PICOFs was designed through polydopamine (PDA) and a well-dispersed polymer (MPC-co-AO) containing multiple functional groups, forming stable composite (PMCA-TPPICOFs) in which the hydrogen bonding and cation-π interactions between PDA and MPC-co-AO played a key role. The obtained PMCA-TPPICOFs as an adsorbent exhibited strong selectivity for uranyl ions (maximum adsorption capacity was 538 mg g-1). In simulated wastewater with low uranium concentrations, the removal rate reached 98.3%, and the concentration of treated simulated wastewater met discharge standards. Moreover, PMCA-TPPICOFs was suitable for fixed-bed column adsorption because of its favorable structure. According to the research about adsorption mechanism, the adsorption primarily relied on electrostatic interaction and complexation. In summary, PMCA-TPPICOFs exhibited good potential for uranium-containing wastewater treatment, expanding the application of PICOFs. And the proposed functionalization strategy and modified solvothermal method may promote research in the fields of material functionalization and COFs synthesis. ENVIRONMENTAL IMPLICATION: Uranium is a raw material for nuclear energy applications, which is toxic and radioactive. If uranium is discharged with wastewater, it would not only pose a threat to the environmental protection and life safety, but also cause the loss of precious nuclear raw materials. Although adsorption was considered to be an effective way to remove uranium, many of the developed adsorbents were difficult to apply due to the harsh wastewater environment and complex preparation processes. This study reported a novel adsorbent and a new functionalization strategy, which was expected to solve the problem of uranium recovery in wastewater.

Hierarchical Self-Assembled Polyimide Microspheres Functionalized with Amidoxime Groups for Uranium-Containing Wastewater Remediation.

Through molecule self-assembly and subsequent surface functionalization, novel uranium adsorbent AO-OB hierarchical self-assembled polyimide microspheres (AO-OBHSPIMs) were obtained by introducing the amidoxime groups into hierarchical self-assembled polyimide microspheres for the efficient and selective recovery of uranium from wastewater. The results of Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and nitrogen adsorption-desorption isotherm showed that AO-OBHSPIMs were a semicrystalline polymer material with self-supporting hierarchical structure and low pore volume, and they were equipped with abundant amidoxime groups. Given the recognized selectivity of amidoxime groups and their hierarchical structure, AO-OBHSPIMs exhibited excellent selectivity to uranyl ions. Moreover, AO-OBHSPIMs exhibited good stability and recyclability and remarkable removal percentage within low-concentration solution (99.4%) and simulated uranium-containing wastewater (97.3%). AO-OBHSPIMs could be applied to fixed-bed column adsorption due to their large particle size and self-supporting hierarchical structure that can facilitate water flow. The in-depth discussion of the adsorption mechanism showed that the adsorption mainly depended on the combined action of electrostatic interactions and complexation, and the adsorption process was a spontaneous endothermic monolayer adsorption. In summary, AO-OBHSPIMs exhibited good application prospects in uranium-containing wastewater remediation.

Platelet-derived Growth Factor-α and Neuropilin-1 Mediate Lung Fibroblast Response to Rigid Collagen Fibers.

During pulmonary secondary alveolar septation, the rudimentary distal saccule subdivides by extending tissue sheets into the saccular air space, creating alveoli, which open into the alveolar duct. The sheets originate from saccular mesenchymal cells, which contain α-SMA (αSMA [ACTA2]) and abut elastic fibers (myofibroblasts [MF]), characteristics that are shared by cells that subsequently occupy the secondary septal tips. During elongation, collagen fibers are positioned to provide a scaffold for translocating septal mesenchymal cells. We hypothesized that collagen fibers direct the migration, orientation, and location of MFs during septal elongation. To address this hypothesis, we examined how electrospun collagen fibers direct the migration of fibroblasts bearing targeted deletions of PDGFRα (platelet-derived growth factor receptor-α) or Nrp1 (neuropilin-1), after their isolation from lungs that exhibit reduced secondary septation. We observed that deletion of either gene reduced Rac1 activation and the speed of migration of lung fibroblasts (LF) along electrospun fibers. The deletions did not reduce the proportion of LF that displayed collagen-binding integrins and increased the proportion of LF bearing activated ß1-integrin. LF bearing the PDGFRα deletion failed to localize focal adhesions over electrospun fibers, suggesting that they may not appropriately sense and respond to regionally increased stiffness near the fibers. In lungs of mice bearing the PDGFRα deletion, collagen fibers are delocalized from ACTA2-containing MF, and their orientation deviated from the plane of the alveolar walls. Diminished PDGFRα or Nrp1 reduces LF localization to stiffer regions of fibrillar collagen substrates, suggesting that signaling through these receptors enables responsiveness to regional differences in extracellular matrix rigidity.

Effect of Core-Shell Morphology on the Mechanical Properties and Crystallization Behavior of HDPE/HDPE-g-MA/PA6 Ternary Blends.

In this paper, the high-density polyethylene/maleic anhydride grafted high-density polyethylene/polyamide 6 (HDPE/HDPE-g-MA/PA6) ternary blends were prepared by blend melting. The binary dispersed phase (HDPE-g-MA/PA6) is of a core-shell structure, which is confirmed by the SEM observation and theoretical calculation. The crystallization behavior and mechanical properties of PA6, HDPE-g-MA, HDPE, and their blends were investigated. The crystallization process, crystallization temperature, melting temperature, and crystallinity were studied by differential scanning calorimetry (DSC) testing. The results show that PA6 and HDPE-g-MA interact with each other during crystallizing, and their crystallization behaviors are different when the composition is different. At the same time, the addition of core-shell particles (HDPE-g-MA/PA6) can affect the crystallization behavior of the HDPE matrix. With the addition of the core-shell particles, the comprehensive mechanical properties of HDPE were enhanced, including tensile strength, elastic modulus, and the impact strength. Combined with previous studies, the toughening mechanism of core-shell structure is discussed in detail. The mechanism of the core-shell structure toughening is not only one, but the result of a variety of mechanisms together.