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Antimicrobial photodynamic therapy (aPDT) is a new therapeutical modality highly advocated recently to meet the challenge of drug resistant bacteria. In this study, we developed a composite material to combine silver nanoparticle, a commonly used disinfectant, with a potent photosensitizer for aPDT. Interestingly, we found the photosensitizer activated the silver nanoparticles into silver ions under light illumination. At the same time, silver nanoparticles enhanced the generation of ROS by the photosensitizer. Together, the two components activates each other, leading to remarkable antimicrobial efficacy against not only gram-positive and -negative bacteria, but also drug resistant bacteria (Methicillin Resistant S. aureus, MRSA). Such antimicrobial effect was further demonstrated on a bacterial infection model on mice. We showed that the chemical treatment, the high temperature or the pressure during the preparation did not affect the cellulosic structures of the fabric based on the characterization of optical, mechanical and thermal properties of the composite material. aPDT is typically a localized therapy, depending on the contact of bacteria to the photosensitizers, while the silver nanoparticles released the silver ions into the solution and can kill the bacteria thereof. Thus, our current study demonstrates the complementarity of aPDT and silver nanoparticles and mutual promotion of antibacterial effects to even drug-resistant bacteria.

In order to guarantee the water quality of reclaimed water in pipeline system, a chlorine bulk-decay model is required for simulation and prediction of chlorine profiles in networks. Conventional chlorine decay models of drinking water are not applicable to reclaimed water due to its complex and varying water quality. In this study, the chlorine decay of reclaimed water was investigated under different operational conditions. Based on these results, different chlorine-reactive substances (CRSs) in reclaimed water were quantified by total chlorine demand (TCD), instantaneous chlorine demand (ICD) and lasting chlorine demand (LCD), respectively. A stoichiometric model (CRS model) of chlorine decay of reclaimed water was established using ICD, TCD and reaction rate constant (k) as key independent parameters. The experimental data were fitted to the CRS model with promising results under various initial chlorine concentrations (3–10 mg-Cl2/L) and temperatures (8–35 °C). The ICD, TCD and k of different reclaimed water samples were in the range of 0.23 to 2.85 mg-Cl2/L, 1.07 to 4.73 mg-Cl2/L, and 0.04 to 4.06 L/(mg·h), respectively. Furthermore, the ICDs, TCDs and k could be determined directly by measuring the chlorine consumption at 5 min (ΔCCl,5min) and 8 h (ΔCCl,8h) after the addition of chlorine into reclaimed water, and the UV254 of reclaimed water, respectively. The relationships between ICD, TCD, k and the corresponding water quality indexes were further validated. In this way, the chlorine decay profile of reclaimed water could be predicted rapidly and precisely by measuring the ΔCCl,5min, ΔCCl,8h, and UV254 of reclaimed water.

The hydration lubrication was proposed by Jacob Klein, a famous tribologist, in 2001. The core of this mechanism is the formation of a strong hydrated layer surrounding polar groups. Over the past 20 years, various lubricating materials have been developed according to this mechanism. Among them, polymer-based lubricating materials have attracted much attention because of their facile tunability of structures and functions. Especially, they have played a tremendous role in functional hydration lubrication, which means that other interesting functions can be integrated into hydration lubrication during water-based friction, such as stimuli-responsive property, biomedical performance and biomimetic design. This review outlines the recent progress of functional polymeric materials employed for realizing versatile hydration lubrication, which are categorized as: (i) stimuli-responsive lubricating materials, through external stimuli to control the interfacial friction; (ii) biomedical lubricating materials, integrating lubricating ability into biomedical materials; (iii) biomimetic lubricating materials, designed by learning from living organisms and nature.

Constructing heterojunction has been widely applied in optimizing photocatalysts for organic pollutant removal. However, incompact contact interface and inappropriate band alignment in the heterointerface of two materials increase interfacial recombination, lowering the degradation efficiency. Herein, a facile strategy without any other surfactants or modification pretreatment was employed to encapsulate cubic Cu2O using metal-organic frameworks (MOFs) to construct heterojunction photocatalysts. The oriented growth of Cu-MOFs (HKUST-1) around cubic Cu2O (Cu2O@HKUST-1) with desired feedstock ratio for enhanced photocatalytic degradation performance was achieved. Compared with the individual components, the optimized Cu2O@HKUST-1 heterostructures exhibited enhanced tetracycline hydrochloride (TC-HCl) removal rate of 93.40% within 60 min under visible light irradiation. Obviously, mechanism exploration revealed that the combined effect between the core-shell structure with compact interfacial contact and an ideal type-II band alignment in Cu2O@HKUST-1 increased the carrier density and accelerated interfacial charge separation and transfer. Meanwhile, HKUST-1 shell protected Cu2O core from the photocorrosion well, assuring the robust stability of photocatalyst during the photocatalytic process. After the fourth cycle, the photocatalytic TC-HCl degradation efficiency and total organic carbon (TOC) removal rate by Cu2O@HKUST-1 remained at 90.02% and 49.64%, respectively. The radical trapping results and electron spin resonance (ESR) identified the h+ and O2− were main active species in this photocatalytic degradation system. Besides, the TC-HCl degradation pathway was investigated by three-dimensional excitation-emission matrix fluorescence spectra and liquid chromatography-mass spectrometry technology. This work provides a facile method towards creating efficient and stable photocatalyst for organic pollutant removal.

MXenes, as newly emerging two-dimensional (2D) transition metal carbides and nitrides, have become promising candidates for environmental remediation and detection due to their hydrophilicity, metallic conductivity, versatile surface chemistry and 2D layered atomic structure. Nevertheless, little attention has been paid to the relationship between the properties of MXenes and their environmental performances. Herein, based on the recent experimental and theoretical research, a systematic review about the environmental applications of MXenes and MXenes-based materials including the removal and detection of toxic metal ions and organic contaminants, capture and mitigation of gas, hydrogen production, membrane- based separation, and disinfection has been done. Various design strategies of MXenes on ameliorating application performance are mentioned, and their suitability in multifarious environmental applications is thoroughly discussed. Based on the specific requirements of the final environmental applications, a targeted description between their properties and their abilities for environmental application is provided. Finally, current challenges and perspectives in this field are proposed from our personal insights. Particular emphasis in this review is directed toward the importance of understanding ultimate the aim and the required attributes to develop the proper materials for specific applications, and facilitates the further evolution of MXenes in environmental applications.

The non-flow property for rigid-rod polymers remains a serious problem that limits their application on a massive scale. Based on a water-in-oil microemulsion method and one pot in situ “grafting to” strategy, a series of novel poly(p-phenylene terephthalamide)-based materials containing controllable graft density of long-chain tertiary amine are prepared. Consequently, the materials’ rheology behaviors are controllable at the level of an order of magnitude and are well-matched with the tunable condensed state structures. Several significant micro-structures of such liquid-like poly(p-phenylene terephthalamide)-based materials are obtained. Additionally, the excellent solubility conforms to the liquid crystal states, solving the key problem of only dissolving concentrated sulfur acid. Additionally, we further investigated the liquid crystal states in different solvents, mass ratios and temperature. This state-of-the-art material with its established property-structure relationship, especially regarding how the structure determines the rheology behavior and solubility, can be treated as a prototype for guiding future research on ionic liquids and in the field related to functional polymer science and technology. Furthermore, the dielectric properties of f -PPTA/PVDF composite membranes have been investigated and show great potential for use in capacitor applications.

Bismuth tungstate (Bi2WO6) was well known for its low price, nontoxicity and stability in the removal of organic pollutions. However, poor visible light absorption and fast carrier recombination led to its moderate activity. Therefore, a Z-scheme photocatalyst constructed by Bi2WO6 nanosheets, graphene oxide (GO) and silver bromide (AgBr) nanoparticles was successfully prepared. Previous reports suggested that Z-scheme structure based on Bi2WO6 nanosheets could obtain more active sites. And characterization results clarified that the addition of AgBr brought broadened visible light response range, inducing more photocarrier generation. Meanwhile, the optimized Z-scheme composite 15%AgBr/5GO/Bi2WO6 (15A/5G/BW) possessed accelerated interfacial charge separation and transfer, which was resulted from excellent electron conductivity in GO. As a result, 15A/5G/BW exhibited superior photocatalytic activities for tetracycline hydrochloride (TC). The highest degradation efficiency could reach 84% under visible light illumination, and the kinetic constant was 0.0515 min−1 which was approximately 4.60 and 3.16 times higher than that of AgBr and Bi2WO6, respectively. Furthermore, liquid chromatography-mass spectrometry (LC-MS) and trapping experiments revealed possible TC degradation pathways and main active radicals during photocatalysis process. A facial strategy for rational design of ternary photocatalyst towards the degradation of refractory antibiotics was proposed.

This study was aimed to investigate the influence of low-frequency alternative pulse current (APC) with square wave on the disinfection performance of carbon fiber-based flow-through electrode system (FES) towards a model bacterium (Escherichia coli). The FES disinfection under direct current (DC) supply was limited by the weak disinfection efficiency of cathode. Compared with DC supply (less than 1 log removal), FES under APC supply achieved superior disinfection performance (over 6 log removal) at the voltage of 3 V and flow rate of 125 mL/min. The optimum condition was acquired when pulse cycle time (T) equaled to hydraulic retention time (HRT), i.e. HRT/T = 1, corresponding to the low frequency (less than 1 Hz), under which the disinfection performance was improved by alternating of anode and cathode. In-situ sampling experiments revealed that redox reactions were carried out alternatively in each electrode, and both electrodes made great contributions to disinfection under APC supply, which was significantly different from DC supply. In addition, FES disinfection under APC supply also caused irreversible damage to bacterial cells, resulting in no bacterial regrowth/reactivation during storage, and guaranteed low energy consumption (11.4 ~ 12.1 Wh/m3) with high flow rate (100 ~ 125 mL/min). Therefore, the development of a novel FES under APC supply provided exciting possibilities for future application of electrochemical disinfection to achieve superior disinfection performance with no bacterial regrowth and low energy consumption.

An economical biochar-supported iron-copper bimetallic composite (BC-FeCu) was successfully prepared and used to remove tetracycline (TC) from water. The experiment results expressed that BC-FeCu exhibited higher removal (92.50%) than FeCu (67.30%) under the same condition (pH 4.50, TC concentration 10 mg/L, and catalyst dose 0.05 g/L). Moreover, the TC removal by BC-FeCu constantly increased with the pH value from 4.50 to 9.03. Desorption experiments showed that adsorption and degradation accounted for 26.09% and 73.91% of the total TC removal by BC-FeCu, respectively. N2 sparging experiments concluded that the degradation led by dissolved oxygen (DO) and the direct degradation by BC-FeCu accounted for 17.02% and 56.89% of the total TC removal, respectively. The existence of O2•−, •OH, 1O2 was testified by electron spin resonance (ESR) analysis. And O2•− was proved to be the dominating active substance for TC degradation by BC-FeCu through quenching experiments. It could be that the electron transferred from –COOH, –OH and Cu/Cu+ in BC-FeCu to O2 to form O2•−, thus realizing the activation of O2. Finally, three possible TC degradation ways were presented through the analysis of eight intermediates.

H2S selective catalytic oxidation, regarded as a green purification technology, has attracted much attention due to its ability to convert H2S to elemental S directly without thermodynamic limitation. Herein, we report for the first time that Co nanoparticles (NPs) with different Co content were encapsulated by N-doped graphitic carbon (3–5 layers) for H2S selective oxidation. The catalytic performance of Co@NC catalysts increases at first and then decreases by increasing the content of Co. It is found that Co@NC-4 with a suitable Co content shows an optimal H2S conversion ratio of nearly 100% with the weight hourly space velocity of 18000 mL g−1 h−1 at 190 °C for 28 h. This high performance may be due to optimal mesopore size and abundant pyridinic N. In contrast, NC sample without Co has conversed nearly 95% of H2S at 250 °C. The theoretical calculation indicates that N-doped graphene can regulate the electron density around the Co NPs, which promotes the adsorption of H2S. We believe that the unique electronic and geometrical configurations improve the activity and stability. Our finding provides a new reference for the study of H2S selective oxidation.

Benzisothiazolinone (BIT) is widely used as a biocide in different industries, and, in particular, in wastewater reclamation plants in which reverse osmosis (RO) is used. BIT can cause dermatitis in humans and is toxic to fish. It is therefore significant to control BIT concentrations in water that is being treated, however, appropriate methods for BIT control and removal have not yet been developed. This study investigated the changes in the concentrations and toxicities of aqueous solutions of BIT, caused by ozonizing the solutions. It was found that BIT was rapidly degraded by ozonation effect, and the rate constant k O 3 ,BIT was 4.17 × 106 L/(mol s). Samples were analyzed using time-of-flight mass spectrometry, and a possible ozonation pathway was proposed from the results. Besides, free energy calculations were performed for characterization of possible products of BIT ozonation. One product, saccharin, was identified, which was produced through the sequential oxidation of sulfur atoms in BIT. The specific ultraviolet absorbances of the BIT solutions decreased and sulfate ions were produced during ozonation. Furthermore, BIT was found to be toxic to zebrafish embryos, with a median lethal concentration of 6.8 μmol/L. Nevertheless, ozonation markedly decreased the toxic effects of BIT to zebrafish embryos, making the toxic effects undetectable. This indicated that the oxidized products were ecologically benign. Since the kinetic rate of BIT ozonation is very fast, compared with (bi)carbonate or humic acid, there is no observable negative interference on BIT ozonation process. Even in the RO concentrate matrix, namely existing complex organic/inorganic components, ozone is still able to quickly degrade BIT as in pure water system. Consequently, ozonation can be considered as an effective method for removing BIT from RO concentrates.

In this report, a N, P co-doped carbon quantum dots (N, P-CQDs) modified silver phosphate united graphene hydrogel (Ag3PO4/NP-CQDs/rGH) photocatalyst with three-dimensional network space structure was designed to build a synergetic photocatalytic activity/stability effect for organic pollutants degradation, which could be confirmed by characterization and photodegradation performance experiments. Convert-light via N, P-CQDs exactly matched for Ag3PO4 could induce more photocarrier generation, meanwhile the N, P-CQDs as an electron acceptor could accelerate the charge separation for anti-photocorrosion. This special network space structure in Ag3PO4/NP-CQDs/rGH photocatalyst provided more reaction active sites to accelerate mineralized reaction process. The photodegradation efficiency of TC in composed wastewater and real wastewater were tested with fresh and used Ag3PO4/NP-CQDs/rGH as photocatalyst. Specifically, the tetracycline hydrochloride (TC) removal rate with Ag3PO4/NP-CQDs/rGH (6%) was found to increase by 20% that of Ag3PO4 and 14% that of N, P-CQDs/Ag3PO4, and the organic pollutants removal efficiency with Ag3PO4/NP-CQDs/rGH photocatalyst maintained at 91.5% at 6th cyclic experiment. Meanwhile, the fresh and after photodegradation efficiency of Ag3PO4/NP-CQDs/rGH (6%) was maintained over 75% in real water matrix. The possible degradation pathway of TC was explored and the photodegradation mechanism was verified by the predominant induce active species ( O2− and h+) in the photocatalytic system. As the consequence, the 3D network space structure Ag3PO4/NP-CQDs/rGH could be applied for sustaining organic pollutants photodegradation in the natural environment production.

The existence of carbamazepine (CBZ) in soil environment has been continuously reported and efficient elimination techniques are imperative. This study investigated the feasibility and the optimal conditions of CBZ degradation in soil by using Fe2+-activated hypochlorite (NaOCl). The Fe2+/H2O2, Fe2+/persulfate and Fe2+/NaOCl systems were applied to degrade CBZ under different initial soil pH conditions, of which Fe2+/NaOCl system achieved a higher CBZ removal rate over a wider pH range. The results indicated that 94.5% of CBZ could be degraded after 4 h when NaOCl concentration was 75 mmol kg−1 at Fe2+/NaOCl molar ratio of 1:1, and the reaction followed pseudo-first-order model. The CBZ removal efficiency could be improved with the increasing of NaOCl dosage. The reduction of initial CBZ concentration had a dual effect on CBZ removal efficiency at a fixed NaOCl dosage. Raising the temperature could considerably speed up the reaction. The high liquid to soil ratio, excessive humic acid and inorganic anions (Cl−, HCO3−) were not conducive to CBZ removal. Electron Spin Resonance (ESR) confirmed that the Fe2+/NaOCl system yield more hydroxyl radicals (HO ) than that of NaOCl alone for CBZ degradation. The transformation pathways were proposed for CBZ degradation based on the identified intermediates. The investigation with soil surface morphology and mineral composition (Fe, Mn, Cu and Zn) showed no significant differences between the original and the treated soil samples, while the soil microbial community was negatively affected.

The present work demonstrates how drug-loaded mesoporous silica nanoparticles (MSNPs) can be prepared by a sequential flash nanoprecipitation (FNP) technique. A sequential FNP technique is developed relying on a combination of two multi-inlet vortex mixers (MIVM), by which a continuous process that involves the formation of micelle-based templates followed by an in situ formation of MSNPs is achieved. Moreover, a widely used biological nematicide, abamectin (Abm), is added during the formation of micelles, ultimately leading to Abm-loaded MSNPs with high encapsulation efficiency. The obtained Abm-loaded MSNPs show excellent stability and inhibition activity against the livability of Meloidogyne incognita. Importantly, the parameters of the resulting MSNPs, such as silica shell thickness and inner cavity size of MSNPs, can be easily controlled by tuning the compositions of the reactant streams. We believe that such a simple approach towards direct preparation of drug-loaded MSNPs would find promising up-scale applications in various fields, such as drug delivery, bioimaging, and formulation technology.

Limited energy density of carbon material stimulates the further development of other advanced negative electrodes for supercapacitors. Herein, a facile strategy is presented for the fabrication of nitrogen-doped carbon matrix encapsulated with the Fe3C/Fe nanoparticles core-shell architectures. The obtained hybrid is constructed by interwoven carbon nanosheets, pod-like carbon nanotubes and Fe3C/Fe nanoparticles, yielding integrated porous conductive networks. Interestingly, after fifteen cyclic voltammetry cycles, the Fe3C/Fe@NC as negative electrode exhibits a much enhanced pseudocapacitance of 1695 F g−1 at 2 A g−1. The in-depth analyses indicate that a dominant Fe3O4 phase with new morphology is formed during the electrochemical activation processes. Thus, the authentic active species accounted for the Faradaic redox reactions should be the Fe3O4, rather than the Fe3C/Fe itself. Furthermore, the assembled asymmetric supercapacitor with Fe3C/Fe@NC as the anode and Ni(OH)2 as the cathode delivers a high energy density of 72 Wh kg−1 at a power density of 0.83 kW kg−1 and a long cycling life, which is superior to those of other reported iron-based materials. This work not only provides a simple in situ activation approach to realize the utilization of Fe3C/Fe, but also paves an avenue for developing advanced negative materials for supercapacitors.

This work presents an effective and new method for producing solid lipid nanoparticles (SLNs) with small sizes (mean diameter less than 250 nm) and relatively narrow size distribution (polydispersity less than 0.26). The preparation process was conducted in a co-flowing microchannel assembled with inner and outer capillaries. A lipid-solvent phase was injected into the inner capillary, while an aqueous phase with surfactant was injected into the outer capillary. The solvent in the lipid-solvent phase diffused into the aqueous phase when the two phases meet in the outer capillary, resulting in the local supersaturation of lipid and finally the formation of SLNs. Softisan 100 (triglyceride mixture of fatty acids with chain lengths of C 10 to C 18 ) was used as the test lipid and SLNs were prepared in the present microchannel system under various operation conditions. The mean diameter and the size distribution of the SLNs obtained were measured by dynamic light scattering (DLS) method and the particle morphology was examined by transmission electron microscopy (TEM). The results showed that the diameter of the SLNs decreased with the increases of the aqueous phase velocity and the lipid concentration, while increased slightly with the increases of the surfactant concentration and the lipid-solvent velocity under the test conditions. The corresponding mechanisms were also analyzed and discussed.