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Although microplastics are emerging marine pollutants that have recently attracted increasing attention, it is still difficult to identify their sources. This study reviewed 6487 articles to determine current research trends and found 237 effective concentration points after sorting, which were distributed in four regions and related to freshwater ecosystems. Results found that 15 environmental variables represented natural and anthropogenic environmental characteristics, of which seven environmental variables were selected for experimental modelling. Random forest models fitted sample data, thus facilitating the identification of regional microplastics distribution. The global random forest model had random forest importance scores (RFISs) for gross domestic product, population, and the proportion of agricultural land use were 15.76 %, 15.64 %, and 14.74 %, respectively; these indicate that human activities significantly affected the global distribution of microplastics. In Asia, agriculture and urban activities are the main sources of microplastics, with an RFIS of 11.58 % and 12.24 % for the proportion of agricultural and urban land use, respectively. Activities in urban areas were determined to be the main influencing factors in North America, with an RFIS of 13.92 % for the proportion of urban land use. Agricultural activities were the main influencing factors in Europe, with RFISs for the proportion of agricultural land use of 16.90 %. Our results indicate that region-specific policies are required to control microplastics in different regions, with soil composition being a latency factor that affects microplastics' distribution.

Environmental pollution has drawn forth advanced materials and progressive techniques concentrating on sustainable development. Metal-organic frameworks (MOFs) have aroused vast interest resulting from their excellent property in structure and function. Conversely, powdery MOFs in highly crystalline follow with fragility, poor processability and recoverability. Aerogels distinguished by the unique three-dimensional (3D) interconnected pore structures with high porosity and accessible surface area are promising carriers for MOFs. Given these, combining MOFs with aerogels at molecule level to obtain advanced composites is excepted to further enhance their performance with higher practicability. Herein, we focus on the latest studies on the MOFs@aerogel composites. The construction of MOFs@aerogel with different synthetic routes and drying methods are discussed. To explore the connection between structure and performance, pore structure engineering and quantitation of MOFs content are outlined. Furthermore, various types of MOFs@aerogel composites and their carbonized derivatives are reviewed, as well as the applications of MOFs@aerogel for environmental remediation referring to water purification and air clearing. More importantly, outlooks towards these emerging advanced composites have been presented from the perspective of practical application and future development.

The excellent properties of plastics make them widely used all over the world. However, when plastics enter the environmental medium, microplastics will inevitably be produced due to physical, chemical and biological factors. Studies have shown that microplastics have been detected in terrestrial, aquatic and atmospheric environments. In addition, the presence of microplastics will provide a new artificial adhesion substrate for biofilms. It has been proved that the formation of biofilms could significantly change some properties of microplastics. Some studies have found that microplastics attached with biofilms have higher environmental risks and eco-toxicity. Therefore, considering the widespread existence of microplastics and the ecological risks of microplastic biofilms, the physical and chemical properties of biofilms on microplastics and their impact on microplastics in aqueous environment are worth reviewing. In this paper, we comprehensively reviewed representative studies in this area. Firstly, this study reviews that the existence of biofilms could change the transport and deposition of microplastics. Subsequently, the presence of biofilms would enhance the ability of microplastics to accumulate pollutant, such as persistent organic pollutants, heavy metals and antibiotics. Moreover, the effect of biofilms on microplastics enrichment of harmful microorganisms is summarized. Finally, some future research needs and strategies are proposed to better understand the problem of biofilms on microplastics.

Efficient removal of tetracycline (TCN) from aqueous solution is important for water environment security. Herein, magnetic carbon-αFe/Fe3C derived from metal-organic frameworks (MOFs) were synthesized by a carbonization method and used for TCN adsorption. The magnetic carbon-αFe/Fe3C adsorbent was characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), thermal gravimetric analyzer (TGA), X-ray photoelectron spectrum (XPS) and vibrating sample magnetometer (VSM). The resultant magnetic carbon-αFe/Fe3C exhibited outstanding TCN adsorption capacity (511.06 mg g−1) from aqueous solution due to its large specific surface area (171.72 m2 g−1) and pore volume (0.31 cm3 g−1), and abundant active adsorption sites. The main adsorption mechanisms were physisorption and chemisorption, including pore filling effect and electrostatic adsorption. Moreover, magnetic carbon-αFe/Fe3C could remove TCN at low concentrations (

The low separation efficiency of carriers limited the application of g-C3N4 (CN) in the photodegradation of fluoroquinolones antibiotics, and the construction of two-dimensional/two-dimensional (2D/2D) heterojunction was an effective strategy. In this paper, 2D/2D N-ZnO/CN S-scheme heterojunction composites (x NZCN, x was the mass ratio of ZIF-L/CN) were prepared by calcining ZIF-L/CN composites which were formed via ultrasonic-assisted electrostatic self-assembly method. The photodegradation efficiencies of Norfloxacin (NOR), enrofloxacin, levofloxacin, and ciprofloxacin reached more than 90% in 90 min by 15% NZCN/vis system. Moreover, the rate constant of 15% NZCN for photodegrading NOR was 4.15 times and 4.65 times higher than CN and N-ZnO, respectively. The efficient photocatalytic performance of 15% NZCN was attributed to the excellent light capture capacity and the effective migration and separation of carriers. The active species that worked in the photodegradation of NOR were dominated by holes and superoxide radicals. In addition, degradation pathways of NOR were proposed. This work enriched 2D/2D heterojunction engineering for CN, and provided a new possibility for combining 2D MOFs-derivatives with CN to solve the antibiotic pollution problem in the environment.

The application of traditional powder catalysts is limited by particle agglomeration and difficult recovery. In this work, a three-dimensional porous aerogel catalyst for organic pollutants degradation in water by activating peroxydisulfate (PDS) was successfully synthesized, which was obtained via directly mixing of MIL-88B(Fe) with sol precursors followed by vacuum freeze-drying and low-temperature calcination. MIL-88B(Fe)/gelatin aerogel-150/PDS (MGA-150/PDS) system displayed satisfactory norfloxacin (NOR) degradation performance, which could remove 98.7% of NOR in 90 min. Its reaction rate constant was 23.2 times higher than the gelatin aerogel/PDS (GA/PDS) system. In addition, Electron paramagnetic resonance (EPR) results and radical trapping experiments revealed both radicals (SO4•−, •OH) and non-radical (1O2) pathways had participated in NOR degradation, of which •OH was dominant. Possible degradation pathways were proposed. Moreover, the high degradation efficiency of NOR by MGA-150 composites could still be reached more than 90.0% even after 10 cycles, and the morphology and chemical structure of MGA-150 composites exhibited no significant changes, indicating the arrestive stability of aerogel composites. This progress not only proposed an effective catalyst for PDS activation, but also expanded views for the design and development of 3D functional materials.

This study explored the fate of mobile genetic elements (MGEs) in anaerobic digestion (AD) system with four nanoparticles (NPs) added, including carbon NPs, Al2O3 NPs, ZnO NPs, and CuO NPs. 16S rRNA amplicon sequencing and quantitative PCR to investigate the microbial community, MGEs abundance and the potential host in the AD process. The results of high-throughput sequencing showed that ZnO NPs and CuO NPs significantly reduced the microbial diversity and significantly changed the microbial community structure. Simultaneously, the absolute abundance of MGEs increased by 145.01%, 159.67%, 354.70%, and 132.80% on the carbon NPs, Al2O3 NPs, ZnO NPs, and CuO NPs. The enrichment rate of tnpA-03 in ZnO NPs group was the highest, which could reach up to 2854.80%. Co-occurrence analysis revealed that Proteobacteria harbored the vast majority of MGEs followed by Firmicutes. Redundancy analysis and variation partitioning analysis showed that metabolites were the main factors that shifted the succession of bacterial communities. Moreover, there were significant positive correlations between metabolites and part MGEs (such as tnpA-01, tnpA-02, tnpA-03, tnpA-04, tnpA-05, tnpA-07 and ISCR1). This study provides a new perspective that NPs increase the risk of antibiotic resistance through MGEs during AD process.

The lack or incorrect implementation of storage device privacy and secret-related information erasure methods will cause serious security risks for personal privacy and national construction security. Although information erasure based on overwrite for magnetic storage media is relatively mature, it is difficult for these mature technologies to be directly used in the currently widely used NAND flash memory due to its complex structure and other reasons, and its security is in doubt. The recycling industry of waste electronic equipment, mainly smart phones, is facing the problem of lack of information security clearance. In addition to the hidden dangers of information security, this situation also leads to the low recovery rate of waste electronic equipment, which leads to potential waste of resources and environmental pollution. In view of the above problems, this article reviews the information erasure for NAND flash based on the overwrite technology to support the in-depth research of the information erasure technology. At first, it introduces the definition and classification of information erasure. Then, the characteristics of NAND flash memory is analyzed. Thirdly, it summarizes the information erasure technology based on overwriting. And the research difficulties and application difficulties of information erasure technology for NAND flash memory is discussed and analyzed. Finally, conclusions and prospect the future research direction of overwrite-based information erasure technology for NAND flash are given out.

Mill load is one of the key factors that affects the operation optimization and control of grinding process. It is difficult to detect accurately in real time. The mill load relates to multiple channel mechanical signals, such as the mill shell vibration signals, the shaft seat front and rear vibration signals, the acoustic signals near to the shell surface and under the grinding area, etc. How to evaluate these sub-band feature of the mechanical spectrum of the above channels is a difficult problem. It can help to clarify the ball mill grinding mechanism and the mechanical signal generation mechanism. To solve these problems, this paper proposes a multi-channel mechanical frequency spectrum sub-band feature evaluation method based on multiple types correlation analysis. Firstly, the multi-channel mechanical signals are transformed from time domain to frequency domain to obtain the frequency spectrum data, which are divided into several sub-bands to extract features. Then, the normalized correlation coefficients between the multi-channel sub-band feature and the mill load are calculated. Thirdly, based on the partial least square algorithm, the variable projection importance (VIP) value of sub-band features are also calculated. The VIPs are normalized same as that of correlation coefficient. Finally, a new index is calculated by using normalized correlation coefficient and VIP value and the model’s prediction performance. These sub-band features of single channel and all channel mechanical signals are measured based on the new defined combined evaluation index. The multi-channel mechanical signals of a laboratory-scale ball mill are used to verify the effectiveness of the proposed method.

Herein, Mn-doped MIL-53(Fe) were fabricated via one-pot solvothermal method and used for peroxymonosulfate (PMS) activation towards tetracycline (TC) degradation from aqueous solution. The characterizations of SEM, FTIR and XRD were utilized to reveal the morphology and structure of the materials. The results showed that Mn-MIL-53(Fe)-0.3 displayed the optimal catalytic performance, the removal efficiency of TC could reach 93.2%. Moreover, the catalytic activity of Mn-MIL-53(Fe) towards TC under different initial pH values, co-existing anions (Cl-,CO32- and SO42-) and humic acid (HA) were investigated. The results of thermodynamic experiment suggested that the catalytic process was endothermic. In addition, integrated with capture experiments results and the characterization results of electron paramagnetic resonance (EPR), which revealed that SO4·- and HO- were the reactive radicals involving in the reaction. More importantly, the possible activation mechanism was discussed in detail based on the X-ray photoelectron spectroscopy results. The active species were generated by the active sites of Fe(II) and Mn(II) on Mn-MIL-53(Fe) effectively activated PMS. Furthermore, the degradation intermediates and possible degradation pathway were investigated by LC-MS. Finally, the catalyst also showed good performance in actual wastewater and demonstrated good recyclability. The Mn-MIL-53(Fe)/PMS system exhibited a promising application prospect for antibiotic-containing waste water treatment.

Compared with the transition metal induced homogeneous catalytic system, the heterogeneous catalytic system based on transition metal-doped metal organic frameworks (MOFs) were stable for the efficient utilization of transition metal and avoiding the metal leaching. The aim of this work is to synthesize Co-doped MIL-53(Al) by one-step solvent thermal method and use it to activate peroxymonosulfate (PMS) to remove tetracycline (TC) in water. The successful synthesis of Co-MIL-53(Al) samples was demonstrated by XDR, SEM and FTIR characterizations. The 25% Co-MIL-53(Al)/PMS system showed the optimal TC removal effect compared to the PMS alone and MIL-53(Al)/PMS system. The catalytic performances of Co-MIL-53(Al)/PMS system in conditions of different pH, co-existing substances and water bodies were investigated. Quenching experiment and electron paramagnetic resonance (EPR) showed that the degradation mechanism by Co-MIL-53(Al) activation PMS was mainly attributed to sulfate radical (SO4•-) and singlet oxygen (1O2) non-radical. The degradation intermediates of TC were also identified and the possible degradation pathways were proposed. Co-MIL-53(Al) showed good activity after four cycles. These findings demonstrated that Co-MIL-53(Al) can be a promising heterogeneous catalyst for activating PMS to degrade TC.

The preparation of macroscopic objects from metal-organic frameworks (MOFs) derived carbon-based materials is challenging but of great significance to broaden their industrial application. In this work, we have provided a green and effective strategy to synthesize a three-dimensional (3D) compressible Fe-doped nitrogen carbon/gelation aerogel (Fe@NC-800/AG) via a freeze-drying and low-temperature calcination technique. The Fe@NC-800 powders were uniformly and tightly dispersed in the channels of 3D AG. Interestingly, the Fe@NC-800 can function as the mechanical support skeleton and provide catalytic sites to activate peroxymonosulfate (PMS) for degrading various organic pollutants in aqueous solution. The Fe@NC-800/AG/PMS system exhibited outstanding tetracycline (TC) degradation performance (94.3% of TC can be removed after 60 min) and recycling ability (after reused for 10 times, the TC removal efficiency can reach to 90%). Moreover, the integrated multilayer filter composed of two pieces of Fe@NC-800/AG showed high TC removal efficiency (>90%) at the flux of 2.22 mL/min for 420 min. The Fe@NC-800/AG composite with hierarchical pore structure greatly reduced diffusion resistance of pollutants and the 3D compressible property made Fe@NC-800-0.15/AG composite can be easily separated from aqueous solution, which reduced secondary pollution and improved recycling performance. This study provided a feasible strategy to immobilize MOF-derived powders into compressible and tailorable form, which held a novel promise for rationally fabricating 3D MOF-based catalyst with structural diversity.

To explore a green, low-cost, and efficient strategy to synthesis reduced graphene oxide (RGO), the process and mechanism of the graphene oxide (GO) reduction by a model electrochemically active bacteria (EAB), Geobacter sulfurreducens PCA, were studied. In this work, up to 1.0 mg mL−1 of GO was reduced by G. sulfurreducens within 0.5–8 days. ID/IG ratio in reduced product was similar to chemically RGO. After microbial reduction, the peak which corresponded to the reflection of graphene oxide (001) disappeared, while another peak considered as graphite spacing (002) appeared. The peak intensity of typical oxygen function groups, such as carboxyl C–O and >O (epoxide) groups, diminished in bacterially induced RGO comparing to initial GO. Besides, we observed the doping of nitrogen and phosphorus elements in bacterially induced RGO. In a good agreement with that, better electrochemical performance was noticed after GO reduction. As confirmed with differential pulse voltammetry (DPV) and cyclic voltammetry (CV) analysis, the maximum value of peak currents of bacterially induced RGO were significantly higher than those of GO. Our results showed the electron transfer at microbial cell/GO interface promoted the GO reduction, suggesting a broader application of EAB in biological mediated production of RGO.

The environmental concerns and health risks caused by antibiotics have gained growing attention. Metal-organic frameworks (MOFs) are promising adsorbents for antibiotics removal, while limited by poor recyclability due to their powder form. In this study, via frothing and low-temperature carbonization, three-dimensional hierarchical porous ZIF-L/foaming gelatin aerogels (ZIF-L/FGA200) were prepared and targeted to tetracycline (TC) removal. As evidenced by multiple characterizations, ZIF-L was successfully integrated with gelatin aerogels, and the homodisperse of ZIF-L on FGA200 avoiding the agglomeration with more exposed active sites enhanced the adsorption performance as the maximum adsorbing capacity was up to 387.6 mg g−1. The adsorption behavior was well described with pseudo-second-order kinetics and Freundlich isotherm models. The effects of pH, coexisting ions and humic acid were investigated. Based on experimental data and characterizations, several possible adsorbing principles were proposed including electrostatic interaction, hydrogen bonding, π-π interaction and pore filling. Besides, treatment with multiple antibiotics and real samples were carried out. High removal efficiency (>95%) at different flow velocities (1.80–9.65 mL min−1) and satisfactory treatment volume in fixed-bed column adsorption demonstrated the good potentiality of ZIF-L/FGA200 towards practical applications. Moreover, excellent recyclability of ZIF-L/FGA200 was proved after nine adsorption–desorption cycles as the diminished performance was around 8% from 95% to 87%. Overall, ZIF-L/FGA200 was expected to be a potential adsorbent aiming at antibiotic elimination and this strategy might be suitable for loading various materials to prepared advanced composite materials.

The light collection and separation of nano-catalysts in the slurry-system are key issues in photocatalysis. Herein, magnetic Ti3+-TiO2/Ar-Fe2O3 type II heterojunction is fabricated by high-temperature reduction of MOFs in argon atmosphere for solving these issues. The Fe clusters exposed by Ar-Fe2O3 and the high light collection ability brought by oxygen vacancies make Ti3+-TiO2/Ar-Fe2O3 considered for photo-activation of peroxydisulfate (PDS). Ti3+-TiO2/Ar-Fe2O3/visible light/PDS system degrades 97.80 % of Norfloxacin (NOR) within 5 min, the first-order kinetic constants (0.4174 min−1) is 8.73 and 7.31 times that of Ti3+-TiO2 and Ar-Fe2O3. The proposed system also exhibits excellent degradation ability in multiple antibiotics and real samples. Based on the suitable energy band level of Ti3+-TiO2/Ar-Fe2O3, the separation rate of carriers is enhanced, SO4 −, OH and h+ are concomitantly produced for oxidating NOR. This work enriches in-situ defect engineering for TiO2, gives novel insights for MOFs-assisted nano-catalysts and offers a new chance for photo-activation of PDS.

Photocatalysis, which can be utilized for H2 production, CO2 reduction, and water remediation, promising a bright future in addressing energy and environmental challenges. Metal-organic frameworks (MOFs) with highly uniform crystal structures provide internal conditions to restrain the aggregation of metal species and generate the composite with superb stability. Such confinement strategy offers advantages in designing of photocatalysts with abundant active sites, increased mass-transfer efficiency, enhanced light adsorption and high photo-generated carriers utilization rate due to the synergistic effects. Here, the recent advances in fabricating metal species confined in pores of MOFs are concluded. Advanced characterizations for characterizing the relative location between metal species and MOFs are displayed. Moreover, the photocatalytic applications of metal species@MOFs in energy and environment and the corresponding photocatalytic mechanisms are discussed. Challenges and perspectives are given, with good hope to promote the development of fabricating advanced and efficient photocatalyst.

Artificial photosynthesis based on photoelectrochemical (PEC) strategy is another solar-to-chemical energy conversion method besides photocatalysis. Owing to the diversity of structure and the adjustability of synthesis, the metal-organic frameworks (MOFs) can enrich this important research field in the form of constructing a photoelectrode. In addition to solving the problems of difficult recovery for powder and the easy recombination for carriers in photocatalysis, MOFs and their derivatives-modified photoelectrodes can reasonably adjust the PEC activity at the molecular level and increase the contact area between the electrolyte and electrode, thereby facilitating the diffusion of electrolyte and reaction substrate in the electrode. In this review, we comprehensively reviewed representative studies in this area. Firstly, functions of MOFs in photoelectrodes are outlined, and the various synthesis strategies of MOFs-modified photoelectrodes are elaborated. Subsequently, special attention has been paid to the application and mechanism of MOFs-modified photoelectrodes (MIL, ZIF, UiO and PCN) in photo-electrochemistry. And we discuss the stability, reproducibility and reusability of MOFs-modified photoelectrodes. Finally, the challenges and improvements of MOFs-modified photoelectrodes in promoting practical application are proposed. Overall, MOFs and their derivatives-modified photoelectrodes achieved the integration of adsorption, photocatalysis and electrocatalysis. Notably, the research in this field is in infancy, many improvements are required before practical applications.

As the functional material, iron nanoparticles effectively promote anaerobic digestion (AD) process, including the hydrolysis-acidification process and the biogas production. In this study, nano zero-valent iron (nZVI) and Fe3O4 nanoparticles (Fe3O4 NPs) were added to AD reactors respectively. The AD process was evaluated by the reactors performances, including pH, biogas yields and compositions, as well as the removal ratio of total solids (TS), volatile solids (VS) and soluble chemical oxygen demand (sCOD). Three models (first-order kinetic model, transfer function model and Cone model) were used to explore the kinetics of AD biogas production. The results showed that adding appropriate dose of nZVI or Fe3O4 NPs enhanced anaerobic digestibility of sludge. The highest cumulative biogas yield of 140.34 L with 0.5 g L−1 nZVI and 137.13 L with 1 g L−1 Fe3O4 NPs were obtained by the 80 days of mesophilic operation, respectively. Cumulative biogas productions of these two reactors were significantly enhanced up to 15.70% and 13.44%. TS removal rates reached >70% in all AD reactors with iron nanoparticles, and the highest sCOD removal rates of nZVI and Fe3O4 NPs digesters on the 80th day were 88.22% and 77.63%, respectively. The results of the three-day fermentation experiment and the kinetic parameters showed that the nZVI or Fe3O4 NPs enhanced the hydrolysis-acidification process of the AD, which eventually promoted biogas production. The Cone model was satisfied with the experimental results, which could be used to evaluate the kinetics of AD with iron nanoparticles more reasonably.

The exploration of transforming insoluble solid hydroxide as a metal source into metal organic frameworks (MOFs) has attracted much attention in recent years. Herein, Fe-doped cobalt zeolitic imidazolate framework (Co-ZIF-(Fe)x, x meant the different adding amount of Fe3+) were successfully synthesized by using radical cobalt layered double hydroxide (Co(OH)2) as a cobalt ion source. The catalytic performance of samples was evaluated by activating peroxymonosulfate (PMS) to degrade tetracycline hydrochloride (TC) from aqueous solution. Remarkably, the Co-ZIF-(Fe)0.5 demonstrated the highest catalytic activity that the removal efficiency of TC could reach up to 96.71% within 5 min, which was 1.136 times higher than Co-ZIF. The Co-ZIF-(Fe)0.5 have a larger surface area (268.97 m2 g−1) and pore volume (0.25 cm3 g−1), which can be contributed to a large number of accessible active sites. The possible TC degradation pathways were investigated on basis of the intermediates. According to the classical radical-quenching test and electron paramagnetic resonance (EPR) characterization, manifested that the degradation of TC was accomplished by the free radical (SO4 −) and the non-radical (1O2) pathways. Moreover, the Co-ZIF-(Fe)0.5/PMS system exhibited a high activity in a wide pH range (4–10) and less influenced by organic and inorganic ions. The effect of actual water (medical wastewater, river water and tap water) was discussed in detail, and the reusability was also be considered. Therefore, this study provided a reference for the fabricating of MOF-based catalysts for wastewater treatment.

Herein, iron-cobalt layered double hydroxide (FeCo-LDH) was synthesized by sacrificing Co-containing zeolite imidazolate framework materials (ZIF-67) in iron ethanolic solution at room temperature. The catalytic performances of catalysts were investigated by activating peroxymonosulfate (PMS) for tetracycline (TC) degradation. Experimental results were demonstrated that FeCo-LDH with molar ratios of Fe and Co was 1.5 (FeCo-LDH-1.5) exhibited the highest catalytic activity, in which the TC degradation efficiency was reached to 92% within 5 ​min. The system of FeCo-LDH-1.5/PMS exhibited high stability and high efficiency in the influencing factor experiments including TC concentrations, initial pH, coexisting anions (Na+, Cl-, SO42−) and humic acid (HA). Results of quenching experiments and electron paramagnetic resonance (EPR) characterization showed that O2•- and SO4•- radicals were the foremost reactive species for TC degradation. Liquid chromatograph - mass spectrometer (LC-MS) and three-dimensional excitation emission matrix fluorescence spectro photometer (3D EEMs) were conducted to investigate the degradation intermediate and possible degradation pathway. Moreover, high degradation efficiency was implemented in actual wastewater by the FeCo-LDH-1.5/PMS system. Compared to Fe3+/PMS and Co2+/PMS homogeneous system, the FeCo-LDH-1.5/PMS system was exhibited advantages in catalytic activity and high reusability. This study provided a convenient method to synthesis advanced hydrotalcite-like catalysts, which showed remarkable performance in actual wastewater treatment.

N-doped nanoporous carbon (NC) with two-dimensional structure derived from Zn-ZIF-L via KCl exfoliation and carbonization at different temperature were prepared for adsorptive removal of tetracycline (TC). Characterizations revealed the effective dopant of N atoms and low degree of graphitization with more defects related to the enhanced adsorption capacity of the NC materials. Benefiting from the huge surface area (2195.57 m2 g−1), high porosity (1.34 cm3 g−1) and accessible sheeting structure, the NC-800 exhibited its fast and efficient adsorption of TC in 60 min. Meantime, the maximum adsorption of TC could reach 347.06 mg g−1. Effects of pH, humic acid (HA) and ionic strength (Na+, Ca2+) were studied along with the interactions among influencing factors investigated by response surface model (RSM). By optimizing experimental conditions from RSM, the adsorption capacity could increase to 427.41 mg g−1. Additionally, electrostatic interaction and hydrogen bond interaction might play a dominating role in adsorption reaction. The NC-800 could maintain a high adsorption level after four cycles. Therefore, the NC-800 with great adsorptive property and reusability could be considered as an effective adsorbent with promising potential in applications for water treatment.

The integration of metal nanoparticles into carbon materials has catch considerable attention. In this study, we have successfully fabricated the N-doped porous carbon encapsulated magnetic Co nanoparticles (Co@NC-800) through a two-step pyrosis of zeolitic imidazolate frameworks (ZIF-67). The obtained Co@NC-800 exhibited excellent stability in activating peroxymonosulfate (PMS) towards tetracycline (TC) degradation without obvious Co leaching and magnetically separable. The removal efficiency reached up to 90.1% within 3 min and 74.7% of total organic carbon (TOC) removal efficiency could be obtained in 30 min towards TC by Co@NC-800/PMS system. Mechanism explorations revealed the encapsulated Co nanoparticles in the porous N-doped carbon promoted the catalytic activity and stability. The two-pathway mechanism study indicated that radical and non-radical oxidations acted together in TC degradation. Moreover, some potential factors, including PMS dosage, TC concentration, solution pH value, anion/organic matters and temperature were investigated. The Co@NC-800/PMS system exhibited high efficiency in removal of various antibiotics (oxytetracycline, chlortetracycline and deoxytetracycline). Even in actual water bodies (tap water, river water and pharmaceutical wastewater), the Co@NC-800/PMS system displayed excellent performance. This study proposed a design of metal nanoparticles under confinement for fabricating highly active catalysts towards PMS activation.

In this work, we investigated the impact of iron nanoparticle, including magnetite nanoparticles (Fe3O4 NPs) and nanoscale zero-valent iron (nZVI), on the anaerobic digestion (AD) performance. Moreover, the evolutions of antibiotic resistance genes (ARGs), class 1 integrons-integrase (intI1) and potential hosts of ARGs were also investigated. The optimal addition of Fe3O4 NPs and nZVI to promote methane production was 0.5 g/L and 1 g/L, which led to 22.07% and 23.02% increase in methane yield, respectively. The degradation rate of organic matter was also enhanced with the addition of Fe3O4 NPs or nZVI. The results of high-throughput sequencing showed that the reactors with iron NPs exhibited significant differences in microbial community structure, compared to the reactors with the non‑iron NPs. Iron NPs have caused the relative abundance of the dominant bacteria (Proteobacteria, Firmicutes and Actinobacteria) generally decreased, while the dominant archaea (Euryarchaeota) increased in AD sludge. Quantitative PCR results revealed that iron NPs accelerated the reductions in total absolute abundance of ARGs, especially a beta-lactamase resistance encoded gene (blaOXA). Network analysis displayed that the attenuation of ARGs was mainly attributed to the decline of potential hosts (Proteobacteria, Firmicutes and Actinobacteria). Meanwhile, environmental factors (such as pH, soluble chemical oxygen demand and heavy metals) were also strongly correlated with ARGs.

Considering the low recyclability of powder adsorbents, an efficient method is needed to fabricate a novel three-dimensional (3D) adsorbents. Take advantage of the 3D iron network and admirable adsorption performance of the Fe-based metal-organic framework (Fe-MOF), a solvothermal method was used to in-situ growing a series of Fe-based MOFs (MIL-53(Fe) MIL-100(Fe) and MIL-101(Fe)) onto the iron network (MIL stands for Materials of Institute Lavoisier). The successful growing of MILs(Fe) on the iron network was verified by optical microscopy, SEM, XRD, FT-IR and XPS characterizations. As expected, the 3D MILs(Fe) (Fe/MILs) inherited the high adsorption capacity of powdery MILs(Fe), while excellent recycling performance was obtained. Among them, Fe/MIL-100(Fe) exhibited the highest performance towards tetracycline (TC), more than 95% of TC could be removed at fifth adsorption cycle. Mechanism indicated that the π-π and hydrogen bonding (H-bonding) interactions between Fe/MIL-100(Fe) and TC molecules played an essential role in the adsorption process. Besides, the Fe/MIL-100(Fe) adsorbent was stable in water with negligible iron leaching in solution. It is worth noting that Fe/MIL-100(Fe) kept a high adsorption performance towards TC in a wide pH range of 2–10 and suffered minor influence from the anion and humic acid in solution. Even in actual aqueous solution (tap water, river water and pharmaceutical wastewater), high performance was presented by the Fe/MIL-100(Fe) adsorbent. This work provided a new method to synthesis 3D MILs(Fe) adsorbents for wastewater remediation.

Traditional photoanodes decreased in mass transfer rate via coating powdered catalysts on conductive glass. In this work, we obtained a visible light-driven semiconductor- metal organic frameworks (MOFs) hybrid photoelectrode, which was constructed by electro-anodization and deposition growth process. The ZIF-8/NF-TiO2 photoelectrode was based on hollow TiO2 nanotubes, and ZIF-8 nanoparticles were deposited on the surface of the pyramid-shaped rutile TiO2 substrate after N and F co-doping. Compared with unmodified anatase TiO2, the reaction rate of ZIF-8/NF-TiO2 increased by 21.7 times, and the synergistic factor in the photo-electrocatalytic process could reach to 3.5. The porous structure of ZIF-8, the intrinsic band difference between anatase and rutile TiO2 greatly improved light utilization, and promoted electron–hole separation. The electrode could be easily recycled and exhibit excellent repeatability, and the degradation efficiency almost unchanged after 8 cycles. Moreover, possible degradation pathways and photo-electrocatalytic degradation mechanisms of sulfamethazine were proposed. This progress could bring novel insights for the design of semiconductor-MOFs hybrid photo-electrocatalysts.

The effects of four conductive nanomaterials (nano-carbon powder, nano-Al2O3, nano-ZnO, nano-CuO) on sludge anaerobic digestion (AD) performance and microbial community were investigated through a 36-day fermentation experiment. Results showed that biogas production enhanced by 16.9% and 23.4% with nano-carbon powder and nano-Al2O3 added but decreased by 90.2% and 17.3% with nano-ZnO and nano-CuO. Total solids (TS) removal efficiency was increased by 38.73% and 27.11% with nano-carbon powder and nano-Al2O3 added but decreased by 70.67% and 43.70% with nano-ZnO and nano-CuO. Kinetic analysis indicated four conductive nanomaterials could shorten the lag phase of AD sludge with an average rate of 51.75%. 16S rRNA amplicon sequencing results demonstrated microbes such as Syntrophomonas and Methanosaeta were enriched in nano-carbon powder and nano-Al2O3 reactors. However, microbial community diversity and richness were both inhibited by adding nano-ZnO and nano-CuO. Redundancy analysis (RDA) revealed that genera belong to Firmicutes and Chloroflexi could conduce to methanogenesis process.

In consideration of the complex synthesis of layered double hydroxides (LDHs), a simple and efficient strategy was needed to design and fabricate LDHs with high performance. In this study, aluminum-cobalt layered double hydroxide (AlCo-LDH) with uniformly distributed component was synthesized by in-situ etching of cobalt zeolitic imidazolate framework (Co-ZIF) at room temperature. The obtained AlCo-LDH showed high catalysis performance of tetracycline (TC) degradation via the activation of peroxymonosulfate (PMS). The removal efficiency can reach to 92.3% within 5 min and 49.1% of TOC removal efficiency could be obtained in 30 min. Moreover, the degradation rate constants of AlCo-LDH/PMS system (0.980 min−1) was about 16.6 times higher than Co-ZIF/PMS system (0.059 min−1). The unique hydrotalcite-like layered structure of AlCo-LDH with large surface area and volume made TC molecules diffused and interacted with the reaction sites more easily. More importantly, the higher content of Al ions in AlCo-LDH catalyst helped the low content of Co ions to activate PMS. The forming process of AlCo-LDH and the TC degradation mechanisms were investigated. The quenching experiments combined with electron paramagnetic resonance (EPR) analysis showed the SO4 − and 1O2 radicals were the main reactive species for TC degradation. Moreover, the AlCo-LDH catalyst was stable in water for the negligible leaking of metal ions. Significantly, the AlCo-LDH/PMS system was effective and almost unaffected by pH values, organic and inorganic matters in water. In addition, high removal efficiencies were achieved in various real samples by the AlCo-LDH/PMS system. This work provided a novel and facile route to synthesis advanced MOF-derived LDHs catalyst with high performance in remediation of actual wastewater.

Recently, metal-organic frameworks with high porosity have drawn extensive attention in environment remediation. Herein, a variety of porous metal-organic frameworks were synthesized, including MIL-53(Fe), NH2-MIL-53(Fe), NO2-MIL-53(Fe) and Br-MIL-53(Fe), to adsorb tetracycline (TCN) from aqueous solution. Results showed that the functionalized MIL-53(Fe) exhibited higher adsorption performance than the pristine MIL-53(Fe). Among MIL-53(Fe) series, Br-MIL-53(Fe) had the highest maximum adsorption capacity of 309.6 mg g−1. Effects of initial pH values, co-existed ions and humic acid on the adsorption performance of functionalized MIL-53(Fe) were investigated. The adsorption kinetics fitted well with pseudo-second order model and the adsorption isotherms matched Langmuir model, which suggested that the adsorption process was dominant by chemisorption and the adsorption surface was homogenous. Additionally, adsorption thermodynamics showed that the adsorption process of TCN on MIL-53(Fe) series were spontaneous and endothermic. More importantly, the functionalized MIL-53(Fe) demonstrated excellent recyclability and the detailed adsorption mechanism was discussed. Therefore, this work provided a strategy for fabrication of efficient MOFs-based adsorbent for antibiotic-containing wastewater treatment.

The effect of nanoscale zero-valent iron (NZVI) and magnetite nanoparticles (Fe3O4 NPs) on anaerobic digestion (AD) performance was investigated through a series of 100-day semi-continuous mesophilic anaerobic digestions. The results indicated that biogas production had increased by 24.44% and 21.66% with the addition of 0.5 g/L Fe3O4 NPs and 1.0 g/L NZVI, respectively. Besides, the abundance of five widespread antibiotic resistance genes (ARGs) (ermF, ermA, ermT, aac(6′)-IB, blaOXA-1) was also studied. The decrease in abundance of aac(6′)-IB and blaOXA-1 was observed during the AD process with an average removal rate of 95.69% and 44.82%, respectively. Most of the ARGs, especially ermA and ermT, were less abundant in NZVI group compared with control group. The overall results suggested that the addition of NZVI and Fe3O4 NPs contributed to a better sludge anaerobic digestion performance, and NZVI was beneficial to the removal of some ARGs.

Most of the intrusion detection models (IDM) are constructed with off-line training data. Time-variance characteristic of the practical network system cannot be embodied in the off-line constructed IDM. On-line updating of the off-line IDM with the valued new samples is very necessary. In this paper, a new on-line instruction detection model based on approximate linear dependent (ALD) condition with linear latent feature extraction is proposed to address this problem. Specifically, the valued samples which can represent drift of the practical network are indentified with ALD and prior knowledge. Then, these selected samples are used to update the off-line IDM based on on-line latent feature extraction method and fast machine learning algorithm with sample-based updating strategy. Experiments based on KDD99 data are used to validate the proposed approach.

Simulate metamodeling technique based on complex physical model is one of the key methods to improve simulation effectiveness and assist decision maker to cognize behavior of complex system. There are strong collinearity among input variables of the simulate metamodel. Moreover, number of the training samples is also limited. Popularly used back propagation neural network (BPNN) model suffers from lower learning speed and over-fitting problems. Although random vector functional-link (RVFL) networks have faster learning speed, its prediction performance stability isn't satisfied for modeling little sample data. Thus, a new selective ensemble simulates meta-modeling approach based on latent features extraction and kernel learning is proposed. Partial least square (PLS) is used to extract the latent features from original input variables, which can eliminate collinearity among inputs and simplify structure of the simulate metamodel. Kernel based RVFL (KRVFL) networks, selective ensemble learning and global optimization viewpoint based modeling parameters selection algorithms are used to improve prediction accuracy and satiability of the simulate metamodel. Simulate results show that the proposed approach is effective.