Singlet oxygen generation in light-assisted peroxymonosulfate activation by carbon nitride: Role of elevated crystallinity.

Carbon nitride (CN) is an emerging 2D non-metal semiconductor material that could be used in photocatalysis and advanced oxidation processes (AOPs) for pollutants degradation. The radical-induced degradation by CN in photocatalysis or photo-assisted AOPs was widely reported in previous studies. Nevertheless, how the non-radical degradation by CN materials could be achieved under irradiation is neither well understood nor controlled. In this work, crystalline carbon nitride (CCN) was synthesized via a facile molten-salt method, and used to activate peroxymonosulfate (PMS) under visible light (>420 nm) to selectively and efficiently degrade tetracycline (TC). Compared to the traditional polymeric carbon nitride (PCN), CCN was found to be a superior PMS activator with the assistance of visible light, which was ascribed to the increased crystallinity of CN tri-s-triazine units and the increased number of catalytic sites, thereby optimizing the photoelectric properties. The activation performance could be further improved by copper loading, with TC degradation rate nearly six times more than that of PCN. EPR trapping and quenching tests showed that singlet oxygen (1O2) was the dominant reactive oxygen species in the CCN/PMS/visible light system, attributing to the increased graphitic N sites and formation of electron-deficient C in C-N bonding between neighboring tri-s-triazine units upon crystallinity elevation in CCN. In contrast to the conventional radical-based photocatalysis and AOP processes, the visible light-assisted non-radical AOP degradation was highlighted for the selectivity and the remarkable resistance to the impacts of background inorganic anions or natural organic matter (up to 10 mg/L) in the actual water matrix. This work revealed the 1O2 generation mechanism by CN-based materials under the joint assistance of visible light illumination and crystallinity elevation, and its excellent removal performance demonstrates the great potential of CCN-based materials in the practical wastewater treatment.

Preparation of Cu modified g-C3N4 nanorod bundles for efficiently photocatalytic CO2 reduction.

Carbon nitride-based photocatalysts for CO2 reduction have received great attention. The introduction of transition metals can effectively improve the photocatalytic efficiency of carbon nitride. However, how to introduce transition metals into carbon nitride in more ways remains a challenge. Herein, the Cu modified g-C3N4 nanorod bundles (CCNBs) were prepared by chemical vapor co-deposition using the mixture of urea and chlorophyllin sodium copper salt as precursor. The prepared CCNBs exhibited excellent photocatalytic activity for CO2 reduction. The unique hierarchical structure was beneficial to enhance light harvesting. Besides, the introduction of uniformly dispersed Cu further improved the absorption capacity of visible light, increased active sites, and promoted the separation and transfer of carriers. The CO yield of CCNBs was 5 times higher than that of bulk g-C3N4, and showed excellent stability in cycle experiments. This work provides a strategy to prepare carbon nitride-based photocatalysts for efficient CO2 reduction.

Asymmetric Cellulose/Carbon Nanotubes Membrane with Interconnected Pores Fabricated by Droplet Method for Solar-Driven Interfacial Evaporation and Desalination.

Solar-driven interfacial water purification and desalination have attracted much attention in environmentally friendly water treatment field. The structure design of the photothermal materials is still a critical factor to improve the evaporation performance such as evaporation rate and energy conversion efficiency. Herein, an asymmetric cellulose/carbon nanotubes membrane was designed as the photothermal membrane via a modified droplet method. Under 1 sun irradiation, the evaporation rate and energy efficiency of pure water can reach up to 1.6 kg m-2 h-1 and 89%, respectively. Moreover, stable reusability and desalination performance made the cellulose/carbon nanotubes membrane a promising photothermal membrane which can be used for solar-driven desalination.

Interfacial solar vapor generation for desalination and brine treatment: Evaluating current strategies of solving scaling.

Interfacial solar vapor generation, an efficient, sustainable, and low-cost method for producing clean water, has attracted great interest for application in solar desalination and wastewater treatment. Although recent studies indicated significant enhancement of overall performance by developing photothermal materials and constructing different dimensional systems, stable evaporation performance and long-term operation of the evaporator are hindered by severe scaling issues. In this critical review, we present the latest strategies in reducing salt accumulation on the evaporator for solar desalination and brine treatment. We first demonstrate the consequences of salt accumulation, and then discuss various self-cleaning methods based on bio-inspired concepts and other strategies such as physical cleaning, ion rejection and exchange, fast ion diffusion, and controlled crystallization, etc. Importantly, we discuss and address the rational design of the evaporator via establishing a relationship model between its porosity, thickness, and thermal conductivity. Lastly, we evaluate salt-resistance strategies, evaporation performance, and possibilities of real application in different evaporation systems with scaling-resistant abilities.

Tubular g-C3N4/carbon framework for high-efficiency photocatalytic degradation of methylene blue.

The preparation of high-efficiency, pollution-free photocatalysts for water treatment has always been one of the research hotspots. In this paper, a carbon framework formed from waste grapefruit peel is used as the carrier. A simple one-step chemical vapor deposition (CVD) method allows tubular g-C3N4 to grow on the carbon framework. Tubular g-C3N4 increases the specific surface area of bulk g-C3N4 and enhances the absorption of visible light. At the same time, the carbon framework can effectively promote the separation and transfer of charges. The dual effects of static adsorption and photodegradation enable the g-C3N4/carbon (CNC) framework to quickly remove about 98% of methylene blue within 180 min. The recyclability indicates that the tubular g-C3N4 can stably exist on the carbon framework during the photodegradation process. In the dynamic photocatalytic test driven by gravity, roughly 77.65% of the methylene blue was degraded by the CNC framework. Our work provides an attractive strategy for constructing a composite carbon framework photocatalyst based on the tubular g-C3N4 structure and improving the photocatalytic performance.

Willow Catkins-Derived Porous Carbon Membrane with Hydrophilic Property for Efficient Solar Steam Generation.

Biomass wastes are abundant and common in our daily life, and they are cost-effective, promising, and renewable. Herein, collected willow catkins were used to prepare a hydrophilic biochar composite membrane, which was placed in a tree-like evaporation configuration to simulate a natural transpiration process. The strong light absorption (∼96%) of the biochar layer could harvest light and convert it into thermal energy, which then is used to heat the surrounding water pumped by a porous water channel via capillary action. A hydrophilic light-absorber layer remarkably increased the attachment sites of water molecules, thereby maximizing the use of thermal energy. At the same time, hierarchically porous structure and large specific surface area (∼1380 m2 g-1) supplied more available channels for rapid water vapor diffusion. The as-prepared composite membrane with a low-cost advantage realized a high evaporation rate (1.65 kg m-2 h-1) only under 1 sun illumination (1 kW m-2), which was improved by roughly 27% in comparison with the unmodified hydrophobic composite membrane. The tree-like evaporation configuration with excellent heat localization resulted in the evaporator achieving a high solar-to-vapor conversion efficiency of ∼90.5%. Besides, the composite membrane could remove 99.9% sodium ions from actual seawater and 99.5% heavy metal ions from simulated wastewater, and the long-term stable evaporation performance proved its potential in actual solar desalination. This work not only fabricated an efficient evaporator but also provided a strategy for reusing various natural wastes for water purification.

Emodin relieved lipopolysaccharide-evoked inflammatory damage in WI-38 cells by up-regulating taurine up-regulated gene 1.

BACKGROUND: Neonatal pneumonia (NP) has a high fatality rate in neonatal illness. This research investigated the functions of emodin on lipopolysaccharide (LPS)-evoked inflammatory injury in WI-38 cells. METHODS: Cell counting kit-8 (CCK-8) assay and flow cytometry were utilized for examining the impacts of LPS and emodin on viability and apoptosis, respectively. Taurine up-regulated gene 1 (TUG1) level was altered through cell transfection and investigated by reverse transcription quantitative polymerase chain reaction (RT-qPCR). Moreover, RT-qPCR, western blot and enzyme-linked immunosorbent assay (ELISA) were utilized for investigating expressions of monocyte chemoattractant protein-1 (MCP-1) and interleukin (IL)-6. Western blot was carried out for investigating the levels of Bcl-2, Bax, pro-Caspase-3, cleaved-Caspase-3 and NF-κB and p38MAPK pathway-related proteins. RESULTS: LPS treatment restrained cell viability, enhanced apoptosis, and expressions of inflammation-related IL-6 and MCP-1. Emodin alleviated LPS-evoked inflammatory injury and restrained the NF-κB and p38MAPK pathways. Furthermore, emodin positively regulated TUG1 expression and TUG1 silencing could reverse the efficacy of emodin on IL-6 and MCP-1 expressions. Finally, TUG1 regulates the expression of inflammatory factors through NF-κB and p38MAPK pathways. CONCLUSION: Emodin alleviated LPS-evoked inflammatory injury by raising TUG1 expression via NF-κB and p38MAPK pathways in WI-38 cells.

Hydrophilic polymer-stabilized porous composite membrane for water evaporation and solar desalination.

Solar steam generation is considered an effective and sustainable method for addressing freshwater shortages. However, several challenges to developing photothermal materials and improving evaporation performance currently exist. Herein, we designed a hydrophilic evaporator with double-layer structure by combining a hydrophilic polymer with three-dimensional porous carbon nanotube beads on a glass microfiber membrane. Poly(methacrylic acid) acted as a binder to stabilize the carbon-based photothermal layer along with continuously pumped water. The assembled carbon nanotube beads with porous structures not only harvested and converted light to heat but also provided available channels for fast vapor diffusion. An artificial tree evaporation configuration can effectively localize heat on the photothermal layer, which endowed the evaporator with a high evaporation rate of 1.62 kg m-2 h-1 with a solar-to-vapor energy conversion efficiency of 87% under 1 sun illumination. Meanwhile, excellent desalination performance and stable recycling test made the evaporator have great potential in practical applications.

Electrospun superhydrophilic membranes for effective removal of Pb(ii) from water.

Nanofibrous membranes have a high specific surface area and large porosity, which are beneficial for being used as adsorbents to remove heavy metal ions from water. In this work, electrospun nanofibers were wrapped with a hydrogel layer with a tunable thickness, which endowed the membrane with excellent superhydrophilic performance. Because of good water-retention properties and abundant functional groups originating from the hydrogel layer, as a static adsorbent, the maximum adsorption capacity of Pb(ii) was up to 146.21 mg g-1 according to the Langmuir model. Meanwhile, the electrospun membrane also possessed water permeability as a flow-through membrane for dynamic adsorption, which was obviously different from traditional hydrogel adsorbents. As a result, the rejection ratio of Pb(ii) can remain over 55% after running for 72 h under high pH conditions and at low initial ion concentrations. Apart from these, cycle operations confirmed the regeneration of the membrane, and competitive adsorption experiments illustrated the selective removal of Pb(ii) in a mixed ion solution.

Protective effect of luteolin on skin ischemia-reperfusion injury through an AKT-dependent mechanism.

Cutaneous ischemia­reperfusion (I/R) injury is one of the most crucial problems in flap surgery, which affects the survival of the skin flap and patient prognosis, luteolin, a plant derived flavonoid, has previously been shown to exert a variety of beneficial effects for reducing I/R injury in several organs. The aim of the present study was to evaluate the anti­inflammatory and anti­oxidative stress effects of luteolin on cutaneous I/R injury. The in vitro study were performed using a permanent human immortalized epidermal keratinocyte cell line (HaCaT), cells were cultured in the presence of luteolin and were then treated with hydrogen peroxide, the cell viability, mitochondrial membrane potential and the cell survival/apoptosis related signaling pathway activation were assessed to investigate the cytoprotective effects of luteolin. For in vivo experiments, skin flap I/R injury animal model was established in Sprague­Dawley rats, by measuring the area of flap survival, analyzing the expression of pro­inflammatory cytokine and evaluation of the histological changes in the skin tissue, the protective effects of luteolin on skin I/R injury were investigated. The function of protein kinase B (AKT) and heme oxygenase­1 (HO­1) activation on luteolin mediated I/R injury protection was assessed by administration of phosphoinositide­3­kinase/AKT inhibitor LY294002 and HO­1 inhibitor ZNPP. The results showed that luteolin treatment significantly increased the viability of HaCaT cells upon exposure to hydrogen peroxide, and the administration of luteolin in vivo significantly improved skin flap survival in the I/R injury rat model. The mechanisms underlying these beneficial effects included increased phosphoinositide­3­kinase/protein kinase B activation, improved expression of antioxidant enzyme, and scavenging the cytotoxic effects of reactive oxygen species (ROS). Taken together, the results suggested that luteolin preconditioning yielded significant protection against cutaneous I/R injury by protecting skin keratinocytes from ROS­induced damage.

Raspberry-like PS/CdTe/Silica Microspheres for Fluorescent Superhydrophobic Materials.

Superhydrophobic particulate films were fabricated via deposition of raspberry-like fluorescent PS/CdTe/silica microspheres on clean glass substrates and surface modification. Particularly, the fluorescent microspheres were prepared by a kind of modified strategy, namely introducing poly (acrylic acid)-functionalized polystyrene microspheres and thiol-stabilized CdTe quantum dots into a hydrolysis reaction of tetraethoxysilane simultaneously. And through adjusting the reaction parameters, the polystyrene spheres with two particle sizes and three colors of CdTe quantum dots aqueous solution were obtained. Consequently, raspberry-like microspheres consist of polystyrene cores and the composite shells of CdTe quantum dots and silica. These microspheres possess a fluorescent characteristic and form a hierarchical dual roughness which was conductive to superhydrophobicity, and the hydrophobic tests also showed the contact angles of water droplets on the surface of the raspberry-like microspheres which were over 160° at room temperature.