Rapid visible-light degradation of EE2 and its estrogenicity in hospital wastewater by crystalline promoted g-C3N4

Ultrasonic neural regulation over two-dimensional graphene analog biomaterials: Enhanced PC12 cell differentiation under diverse ultrasond excitation

Two-dimensional (2D) biomaterials, with unique planar topology and quantum effect, have been widely recognized as a versatile nanoplatform for bioimaging, drug delivery and tissue engineering. However, during the complex application of nerve repair, in which inflammatory microenvironment control is imperative, the gentle manipulation and trigger of 2D biomaterials with inclusion and diversity is still challenging. Herein, inspired by the emerging clinical progress of ultrasound neuromodulation, we systematically studied ultrasound-excited 2D graphene analogues (graphene, graphene oxide, reduced graphene oxide (rGO) and carbon nitride) to explore their feasibility, accessibility, and adjustability for ultrasound-induced nerve repair in vitro. Quantitative observation of cell differentiation morphology demonstrates that PC12 cells added with rGO show the best compatibility and differentiation performance under the general ultrasound mode (0.5 w/cm2, 2 min/day) compared with graphene, graphene oxide and carbon nitride. Furthermore, the general condition can be improved by using a higher intensity of 0.7 w/cm2, but it cannot go up further. Later, ultrasonic frequency and duty cycle conditions were investigated to demonstrate the unique and remarkable inclusion and diversity of ultrasound over conventional electrical and surgical means. The pulse waveform with power of 1 MHz and duty cycle of 50 % may be even better, while the 3 MHz and 100 % duty cycle may not work. Overall, various graphene analog materials can be regarded as biosafe and accessible in both fundamental research and clinical ultrasound therapy, even for radiologists without material backgrounds. The enormous potential of diverse and personalized 2D biomaterials-based therapies can be expected to provide a new mode of ultrasound neuromodulation.

Solvothermal Synthesis of g-C3N4/TiO2 Hybrid Photocatalyst with a Broaden Activation Spectrum

A solvothermal self-made composite of graphitic carbon nitride (g-C3N4) and commercially available titanium dioxide (TiO2) demonstrated the removal of commercial acid green-25 (AG-25) textile dye in a saline water matrix when activated by ultraviolet (UV) and visible light. The g-C3N4-TiO2 composite was characterized by X-ray diffraction (XRD), Nitrogen sorption–desorption recording and modeling by the Brunauer–Emmett–Teller (BET) theory, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), and electron spin resonance (ESR). The solvothermal process did not modify the crystalline structure of the g-C3N4 and TiO2 but enhanced the surface area by interlayer delamination of g-C3N4. Under a simulated solar spectrum (including UVA/B and vis wavelengths), the degradation rate of AG-25 by the composite was two and four times higher than that of TiO2 and pure g-C3N4, respectively (0.04, 0.02, and 0.01 min−1). Unlike TiO2, the g-C3N4-TiO2 composite was activated with visible light (the UV portion of the solar spectrum was filtered out). This work provides insight into the contribution of various reactive oxidative species (ROS) to the degradation of AG-25 by the composite.

Robust strategies to eliminate endocrine disruptive estrogens in water resources

The widespread occurrence and ubiquitous distribution of estrogens, i.e., estrone (E1), estradiol (E2), and estriol (E3) in our water matrices, is an issue of global concern. Public and regulatory authorities are concerned and placing joint efforts to eliminate estrogens and related environmentally hazardous compounds, due to their toxic influences on the environmental matrices, ecology, and human health, even at low concentrations. However, most of the available literature is focused on the occurrence of estrogens in different water environments with limited treatment options. Thus, a detailed review to fully cover the several treatment processes is needed. This review comprehensively and comparatively discusses many physical, chemical, and biological-based treatments to eliminate natural estrogens, i.e., estrone (E1), estradiol (E2), and estriol (E3) and related synthetic estrogens, e.g., 17α-ethinylestradiol (EE2) and other related hazardous compounds. The covered techniques include adsorption, nanofiltration, ultrafiltration, ultrasonication, photocatalysis of estrogenic compounds, Fenton, Fenton-like and photo-Fenton degradation of estrogenic compounds, electro-Fenton degradation of estrogenic compounds, ozonation, and biological methods for the removal of estrogenic compounds are thoroughly discussed with suitable examples. The studies revealed that treatment plants based on chemical and biological approaches are cost-friendly for removing estrogenic pollutants. Further, there is a need to properly monitor and disposal of the usage of estrogenic drugs in humans and animals. Additional studies are required to explore a robust and more advanced oxidation treatment strategy that can contribute effectively to industrial-scale applications. This review may assist future investigations, monitoring, and removing estrogenic compounds from various environmental matrices. In concluding remarks, a way forward and future perspectives focusing on bridging knowledge gaps in estrogenic compounds removal are also proposed.

Construction of a C-decorated and Cu-doped (Fe,Cu)S/CuFe2O4 solid solution for photo-Fenton degradation of hydrophobic organic contaminant: Enhanced electron transfer and adsorption capacity

To effectively treat the hydrophobic organic contaminant and utilize an industrial solid waste manganese residue (MR), a novel starch-derived carbon (SC)-decorated and Cu-doped (Fe,Cu)S/CuFe₂O₄ solid solution (CFS/CFO@SC) was prepared from MR via mechanical activation treatment of precursor materials followed by one-step pyrolysis and applied as a photo-Fenton catalyst to treat a hydrophobic organic compound, 17α-ethinylestradiol (EE2). Characterization results showed that the CFS/CFO@SC solid solution with unique crystal and electronic structures exhibited high adsorption capacity and catalytic activity, ascribed to that Cu doping and C decorating enhanced its hydrophobicity and BET surface area. The CFS/CFO@SC showed excellent degradation efficiency with nearly 100% of EE2 removal rate in 40 min (degradation rate constant of 0.112 min^-1), and a high mineralization degree with 95.2% of TOC removal in 180 min. This could be ascribed to that C decorating and the formation of CFS/CFO solid solution promoted the charge transfer in a continuous band, resulting in effective separation of photogenerated holes-electrons (h⁺-e^-). The strong interaction of Fe-Cu collaborating with the photoelectron could effectively accelerate the recycle of Fe³⁺/Fe²⁺ and Cu²⁺/Cu⁺, thus generating more active radicals. Moreover, CFS/CFO@SC showed promising stability and recyclability with the EE2 removal rates all >95% after five cycles. This work brings a valuable approach for the rational design of high-performance Fe-based photo-Fenton catalysts for environmental remediation and the valorization of MR.

Enhancement of redox capacity derived from O-doping of g-C3N4/WO3 nanosheets for the photocatalytic degradation of tetracycline under different dissolved oxygen concentration

Element doping is an essential method for adjusting band structure, light absorbance and charge transfer, and separation of semiconductors. Besides this, whether the photocatalyst can function in an oxygen-deficient environment is also important. Herein, a novel Z-scheme heterojunction photocatalyst O-doped g-C₃N₄/WO₃ (OCN/W) was fabricated and used for the photocatalytic degradation of tetracycline (TC) at different dissolved oxygen concentrations. The introduction of O atoms into g-C₃N₄via hydrothermal treatment manipulates the band structure of the material by increasing the conduction band potential, thus producing more ˙O₂^-. The TC removal rate of OCN/W-2.0 is 89.8% within 60 min under visible light irradiation, which is 1.77 times higher than that of porous g-C₃N₄ nanosheets (PCN). Furthermore, the photocatalytic performance of OCN/W-2.0 also reaches 75% even under oxygen-deficient conditions. The effects of different anions and humic acid in the reaction system can be neglected. The enhanced performance can be attributed to the improved charge separation and the outstanding optical properties of the Z-scheme heterojunction. A possible mechanism was postulated, in which ˙O₂^- and h⁺ are the main reactive species in TC degradation. The OCN/W-2.0 shows a stable structure and outstanding reusability. This work provides insight into antibiotics removal under different dissolved oxygen conditions and the design of photocatalysts for practical applications.

UV-LED Combined with Small Bioreactor Platform (SBP) for Degradation of 17α-Ethynylestradiol (EE2) at Very Short Hydraulic Retention Time

Degradation of 17α-ethynylestradiol (EE2) and estrogenicity were examined in a novel oxidative bioreactor (OBR) that combines small bioreactor platform (SBP) capsules and UV-LED (ultraviolet light emission diode) simultaneously, using enriched water and secondary effluent. Preliminary experiments examined three UV-LED wavelengths-267, 279, and 286 nm, with (indirect photolysis) and without (direct photolysis) H₂O₂. The major degradation wavelength for both direct and indirect photolysis was 279 nm, while the major removal gap for direct vs. indirect degradation was at 267 nm. Reduction of EE2 was observed together with reduction of estrogenicity and mineralization, indicating that the EE2 degradation products are not estrogens. Furthermore, slight mineralization occurred with direct photolysis and more significant mineralization with the indirect process. The physical-biological OBR process showed major improvement over other processes studied here, at a very short hydraulic retention time. The OBR can feasibly replace the advanced oxidation process of UV-LED radiation with catalyst in secondary sedimentation tanks with respect to reduction ratio, and with no residual H₂O₂. Further research into this OBR system is warranted, not only for EE2 degradation, but also to determine its capabilities for degrading mixtures of pharmaceuticals and pesticides, both of which have a significant impact on the environment and public health.