Degradation and mechanism of PFOA by peroxymonosulfate activated by nitrogen-doped carbon foam-anchored nZVI in aqueous solutions.

Perfluorooctanoic acid (PFOA) is an emerging pollutant that is non-biodegradable and presents severe environmental and human health risks. In this study, we present an effective and mild approach for PFOA degradation that involves the use of nitrogen-doped carbon foam anchored with nanoscale zero-valent iron (nZVI@NCF) to activate low concentration peroxymonosulfate (PMS) for the treatment. The nZVI@NCF/PMS system efficiently removed 84.4% of PFOA (2.4 µM). The active sites of nZVI@NCF including Fe0 (110) and graphitic nitrogen played crucial roles in the degradation. Electrochemical analyses and density functional theory calculations revealed that nZVI@NCF acted as an electronic donor, transferring electrons to both PMS and PFOA during the reaction. By further analyzing the electron paramagnetic resonance and byproducts, it was determined that electron transfer and singlet oxygen were responsible for PFOA degradation. Three degradation pathways involving decarboxylation and surface reduction of PFOA in the nZVI@NCF/PMS system were determined. Finding from this study indicate that nZVI@NCF/PMS systems are effective in degrading PFOA and thus present a promising persulfate-advanced oxidation process technology for PFAS treatment.

MXene-Enhanced Bi2S3/CdIn2S4 Heterojunction Photosensitive Gate for DEHP Detection in a Signal-On OPECT Aptamer Biosensor.

Organic electrochemical transistors with signal amplification and good stability are expected to play a more important role in the detection of environmental pollutants. However, the bias voltage at the gate may have an effect on the activity of vulnerable biomolecules. In this work, a novel organic photoelectrochemical transistor (OPECT) aptamer biosensor was developed for di(2-ethylhexyl) phthalate (DEHP) detection by combining photoelectrochemical analysis with an organic electrochemical transistor, where MXene/Bi2S3/CdIn2S4 was employed as a photoactive material, target-dependent DNA hybridization chain reaction was used as a signal amplification unit, and Ru(NH3)63+ was selected as a signal enhancement molecule. The poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)-based OPECT biosensor modulated by the MXene/Bi2S3/CdIn2S4 photosensitive material achieved a high current gain of nearly a thousand times at zero bias voltage. The developed signal-on OPECT sensing platform realized sensitive and specific detection of DEHP, with a detection range of 1-200 pM and a minimum detection limit of 0.24 pM under optimized experimental conditions, and its application to real water samples was also evaluated with satisfactory results. Hence, the construction of this OPECT biosensing platform not only provides a promising tool for the detection of DEHP but also reveals the great potential of the OPECT application for the detection of other environmental toxins.

Ascorbic Acid Induced the Improved Oxygen Vacancy Defects of Bi4O5Br2 and Its Application on Photoelectrochemical Detection of DNA Demethylase MBD2 with Improved Detection Sensitivity.

Oxygen vacancy defects (OVs) are one of the main strategies for nanomaterials modification to improve the photoactivity, but current methods for fabricating OVs are usually complicated and harsh. It is important to develop simple, rapid, safe, and mild methods to fabricate OVs. By studying the effects of different weak reducing agents, the concentration of the reducing agent and the reaction time on fabrication of OVs, it is found that L-ascorbic acid (AA) gently and rapidly induces the increase of OVs in Bi4O5Br2 at room temperature. The increased OVs not only improve the adsorption of visible light, but also enhance the photocurrent response. Based on this, the preparation of OVs in Bi4O5Br2 is employed to the development of a photoelectrochemical biosensor for the detection of DNA demethylase of methyl-CpG binding domain protein 2 (MBD2). The biosensor shows a wide linear range of 0.1-400 ng mL-1 and a detection limit as low as 0.03 ng mL-1 (3σ). In addition, the effect of plasticizers on MBD2 activity is evaluated using this sensor. This work not only provides a novel method to prepare OVs in bismuth rich materials, but also explores a new novel evaluation tool for studying the ecotoxicological effects of contaminants.

NAD+ mediated photoelectrochemical biosensor for histone deacetylase Sirt1 detection based on CuO-BiVO4-AgNCs heterojunction and hybridization chain reaction amplification.

BACKGROUND: Histone deacetylate Sirt1 has been involved in many important biological processes and is closely related to the occurrence and development of many diseases. Therefore, the accurate detection of Sirt1 is of great significance for the diagnosis and treatment of diseases caused by Sirt1 and the development of related drugs. RESULTS: In this work, a photoelectrochemical biosensor was developed for Sirt1 detection based on the NAD + mediated Sirt1 recognition and E. Coli DNA ligase activity. CuO-BiVO4p-n heterojunction was employed as the photoactive material, rolling circle amplification (RCA), hybridization chain reaction (HCR) and AgNCs were used as triple signal amplifications. As a bifunctional cofactor, NAD+ played a crucial role for Sirt1 detection, where the peptide deacetylation catalyzed by Sirt1 consumed NAD+, and the decreased amount of NAD + inhibited the activity of E. Coli DNA ligase, leading to the failure on RCA reaction, and improving the HCR reaction. Finally, AgNCs were generated using C-rich DNA as carrier. The surface plasmon effect of AgNCs and its heterojunction with CuO and BiVO4 accelerated the transfer rate of photogenerated carriers and improved the photocurrent signal. When the detection range was 0.001-200 nM, the detection limit of the biosensor was 0.76 pM (S/N = 3). SIGNIFICANCE: The applicability of the method was evaluated by studying the effects of known inhibitors nicotinamide and environmental pollutant halogenated carbazole on Sirt1 enzyme activity. The results showed that this method can be used as a new platform for screening Sirt1 enzyme inhibitors, and also provided a new biomarker for evaluating the ecotoxicological effects of environmental pollutants.

Confined synthesis of g-C3N4 modified porous carbons for efficient removal of Cd ions.

Carbon nitride (C3N4) nanosheets have excellent adsorption capacity, environmental friendliness, and high stability for heavy metal removal. However, its application in Cd-polluted soil is difficult as aggregation induces the specific surface area to substantially decrease. In this study, a series of C3N4 nanosheet-modified porous carbons (C3N4/PC-X) were prepared by a simple one-step calcination of mixed aerogels with different mass ratios (X) of carboxymethyl cellulose (CMC) and melamine. These were based on the confined effect of the CMC aerogel, whose 3D confined region controls the C3N4 morphology and prevents the aggregation of nanosheets. The resulting C3N4/PC-4 exhibited a porous structure with interpenetrating C3N4 nanosheets and carbon rods. C3N4/PC-4 was characterized by SEM, elemental analysis, XRD, FTIR and XPS, and the existence of C3N4 nanosheets was confirmed. Compared with that of unmodified porous carbons, the adsorption capacity of C3N4/PC-4 for Cd ions increased 3.97 times, up to 273.1 mg/g. The adsorption kinetics and adsorption isotherm analyses showed that the adsorption properties were in agreement with the quasi-second-order and Freundlich adsorption models. Moreover, the material had a good passivation effect on the Cd ions in the soil. The confined synthesis of aerogels could be extended to the preparation of other nanostructures.

Photoelectrochemical biosensor for DNA demethylase detection based on enzymatically induced double-stranded DNA digestion by endonuclease-exonuclease system and Bi4O5Br2-Au/CdS photoactive material.

A novel photoelectrochemical (PEC) biosensor for the detection of DNA demethylase MBD2 was developed based on Bi4O5Br2-Au/CdS photosensitive material. Bi4O5Br2 was firstly modified with gold nanoparticles (AuNPs), following with the modification onto the ITO electrode with CdS to realize the strong photocurrent response as a result of AuNPs had good conductibility and the matched energy between CdS and Bi4O5Br2. In the presence of MBD2, double-stranded DNA (dsDNA) on the electrode surface was demethylated, which triggered the digestion activity of endonuclease HpaII to cleave dsDNA and induced the further cleavage of the dsDNA fragment by exonuclease III (Exo III), causing the release of biotin labeled dsDNA and inhibiting the immobilization of streptavidin (SA) onto the electrode surface. As a results, the photocurrent was increased greatly. However, in the absence of MBD2, HpaII digestion activity was inhibited by DNA methylation modification, which further caused the failure in the release of biotin, leading to the successful immobilization of SA onto the electrode to realize a low photocurrent. The sensor had a detection of 0.3-200 ng/mL and a detection limit was 0.09 ng/mL (3σ). The applicability of this PEC strategy was assessed by studying the effect of environmental pollutants on MBD2 activity.

Antibody-free photoelectrochemical biosensor for DNA carboxylation detection based on SnS2@Ti3C2 heterojunction.

As an important epigenetic modification, 5-carboxycytosine (5caC) played an important role in gene regulation, cell differentiation and growth. 5caC existed in many cells and tissues, but it was highly similar to the structure of other cytosine derivatives and had less content in the genome. Therefore, it was urgent to develop a sensitive and highly selective trace biosensor to detect 5caC. A novel photoelectrochemical biosensor was fabricated for 5-carboxy-2'-deoxycytidine-5'-triphosphate (5cadCTP) detection, where SnS2@Ti3C2 nanocomposite was employed as photoactive material, polyethyleneimine was used as 5cadCTP recognition and capture reagent, and Ru(NH3)63+ was used as photosensitizer for signal amplification. Due the good conductivity of Ti3C2 MXene and the matched energy band between Ti3C2 MXene and SnS2, SnS2@Ti3C2 nanocomposite presented strong photoactivity, which was beneficial to the high detection sensitivity. For specific recognition of 5cadCTP, the covalent interaction of -NH2 in 5cadCTP with -COOH on the substrate electrode was used, which was beneficial to the high detection selectivity. A broad linear relationship between photocurrent and 5cadCTP concentration was observed ranging from 1 pM to 0.2 µM. The low detection limit of 260 fM was achieved. The developed method has high detection specificity and can even distinguish 5caC with its derivatives. In addition, the applicability was evaluated by detecting the content change of 5caC in the genomic DNA of rice seedlings after cultured with environmental pollutants. This work provides a novel platform for 5cadCTP detection, and it can also be applied to detect other cytosine derivatives with suitable recognition strategies.

A novel aminated lignin/geopolymer supported with Fe nanoparticles for removing Cr(VI) and naphthalene: Intermediates promoting the reduction of Cr(VI).

A novel, inexpensive and eco-friendly aminated lignin/geopolymer supported with Fe nanoparticles (Fe@N-L-GM) composite was successfully synthesized using kaolin and lignin as the major precursors. The prepared Fe@N-L-GM had larger specific surface area, rich oxygen-containing and nitrogen-containing functional groups, greater electron transfer ability and interconnective porous structure. The Fe@N-L-GM could be employed as the adsorbent of Cr(VI) and the activator of potassium peroxymonosulfate (PMS) for treatment of Cr(VI) and naphthalene (NAP) in wastewater. The adsorption and degradation results indicated that the maximum adsorption capacity of Cr(VI) could reach 65.83 mg g-1, whereas the maximum NAP degradation efficiency could reach 97.81 %. The adsorbed Cr(VI) was mostly converted to the low toxic Cr(III) through the reduction of electron donors such as Fe(II), amino and hydroxyl groups. The quenching experiment results confirmed that ·OH might be the crucial ROSs in mediating NAP degradation. In the simultaneous removal experiment of Cr(VI) and NAP, the Cr(VI) removal rate was significantly improved in the presence of NAP, while phenol as the degradation intermediate of NAP might be the main substance for promoting the reduction of Cr(VI). This work provided the theoretical foundation and a new type of material for the simultaneous removal of heavy metal and persistent organic pollutants (POPs).

Antibody-free photoelectrochemical strategy for simultaneous detection of methylated RNA, METTL3/METTL14 protein and MazF protein based on enhanced photoactivity of MoSe2-BiOI nanocomposite.

Taking advantages of the catalytic activity of METTL3/METTL14 protein towards adenine methylation in RNA sequence and the specific digestion activity of MazF protein towards unmethylated RNA sequence containing ACA bases, a novel photoelectrochemical biosensor was constructed for simultaneous detection of RNA methylation, METTL3/METTL14 protein and MazF protein. MoSe2-BiOI nanocomposite was prepared and considered as photoactive material, catalytic hairpin assembly strategy and in situ generation of electron donors catalyzed by polyaspartic acid-loaded alkaline phosphatase technique were employed as signal amplification. Under the optimum conditions, the detection ranges of methylated RNA, METTL3/METTL14 protein and MazF protein were 0.001-50 nM, 0.001-25 ng/µL, and 0.001-10 U/mL, respectively. The corresponding detection limits were 0.46 pM, 0.51 pg/µL and 0.42 U/µL with S/N = 3. In addition, the effect of drugs and composite pollutants on the activities of MazF proteins was assessed, proving the applicability of the developed method in the field of drug screening for MazF-related diseases. Moreover, the effects of pollutants on the activity of METTL3/METTL14 were also preliminarily explored, providing new information on pathogenic mechanism of pollutants.

Effective adsorption and catalytic reduction of nitrophenols by amino-rich Cu(I)-I coordination polymer.

Nitrophenols are identified as the priority organic pollutants due to the chemical stability, water solubility, persistence, and toxicity to human health and the environment. Hence, removal of nitrophenols from waste water is vitally essential. In this study, amino-rich coordination polymer Cu2I2(MA)2 (MA = melamine) has been applied for efficient adsorption and catalytic reduction of nitrophenols, like 4-nitrophenol (4-NP), 2, 4-dinitrophenol (DNP) and 2, 4, 6-trinitrophenol (TNP). The effect of various parameters like contact time, initial concentrations, pH, and temperature on adsorption were investigated. The adsorption of nitrophenols fitted the pseudo-second-order kinetic model and Langmuir isotherms model well. The maximum adsorption capacities were 285.71, 232.02, and 131.57 mg g-1 for 4-NP, DNP, and TNP when initial concentrations were 50 mg L-1 at 293.15 K, respectively. The adsorption of nitrophenols is a spontaneous, endothermic, and entropy-driven process. The reduction reaction followed the pseudo-first-order kinetics, and the kinetic rate constants were 0.4413, 0.3167, and 0.17538 min-1 for 4-NP, DNP, and TNP, respectively. The effect of initial nitrophenols concentration, anions, and temperature on reduction process was investigated. The mechanism of adsorption and catalytic reduction of Cu2I2(MA)2 was studied. The results demonstrated that Cu2I2(MA)2 exhibits excellent adsorption and catalytic activity to remove nitrophenols.

Photoelectrochemical Biosensor for Histone Deacetylase Sirt1 Detection Based on Polyaspartic Acid-Engaged and Triggered Redox Cycling Amplification and Enhanced Photoactivity of BiVO4 by Gold Nanoparticles and SnS2.

A photoelectrochemical (PEC) biosensor was established for histone deacetylase Sirt1 detection based on the polyaspartic acid (PASP)-mediated redox cycling amplification and Sirt1 catalysis deacetylation-triggered recognition of the deacetylated substrate peptide, using PASP as the recognition reagent. After BiVO4 was composited with gold nanoparticles and SnS2, the photoactivity of the composite was greatly enhanced due to the matched energy band structure. Under the catalysis of Sirt1 enzyme, the acetylated substrate peptide was deacetylated to obtain a positive peptide, which was recognized by negative PASP. In addition to the recognition function, PASP also played other triple roles. First, PASP interacted with the positive peptide to form a double-stranded structure, which led to the electrode interface changing from irregular to regular, resulting in an improved PEC response. Second, PASP was involved into redox cycle amplification due to its reduction to dehydroascorbic acid. Further, it was used for repeated preparation of ascorbic acid to provide electron donors. This process enhanced the PEC response. Third, based on the matched energy band with BiVO4, PASP effectively improved the photoactivity of BiVO4. With multiplex signal amplification, the PEC biosensor showed a wide linear range (1.83-1830 pM) and high detection sensitivity with a low detection limit of 0.732 pM (S/N = 3). The applicability of this method was evaluated by studying the effects of a known inhibitor of nicotinamide and the heavy metal ions of Cd2+ and Pb2+ on Sirt1 enzyme activity, and the results showed that this method not only provided a new platform for screening Sirt1 enzyme inhibitors but also provided new biomarkers for evaluating the ecotoxicological effects of environmental pollutants.

MXene Enhanced Photoactivity of Bi2O3/Bi2S3 Heterojunction with G-wire Superstructure for Photoelectrochemical Detection of TET1 Protein.

Ten-eleven translocation 1 (TET1) protein has the potential to accelerate the oxygenation of 5-methylcytosine to 5-hydroxymethylcytosine (5hmC); then the -CH2OH of 5hmC can further covalently react with -SH catalyzed by M.HhaI methyltransferase. A brand-new photoelectrochemical (PEC) detection technique for the TET1 protein was created in light of this. For this objective, the Bi2O3/Bi2S3 heterojunction was first prepared by a one-pot hydrothermal method and served for photosensitive materials. For further enhancing the photoactivity, Bi2O3/Bi2S3 was blended with MXene to form an energy band-matched structure, thus improving the migration kinetics of photogenerated carriers. For achieving a high sensitivity of detection, a DNA Walker incorporated with the nicking endonuclease (Nb.BbvCI enzyme)-assisted signal amplification strategy was presented to output exponential G-quadruplex fragments. Self-assembly of the free G-quadruplex sequence into a G-wire superstructure with the assistance of Mg2+ provided more loading sites for MB and amplified the PEC signal. The linear range of the biosensor was 0.1-10 µg/mL with a detection limit of 0.024 µg/mL (S/N = 3) for TET1 protein under optimal experimental conditions. The suitability of the proposed method was evaluated by inhibitor screening experiments and the influence of environmental degradation on the activity of TET1 protein.

Development of a sensitive phage-mimotope and horseradish peroxidase based electrochemical immunosensor for detection of O,O-dimethyl organophosphorus pesticides.

In this work, a green, harmless and signal-amplified electrochemical immunosensor based on phage-mimotope M31 (C-P-D-G-N-H-V-P-F-C) and horseradish peroxidase (HRP) was constructed for detecting O,O-dimethyl organophosphorus pesticides (OPs). The glassy carbon electrode (GCE) was modified by nitrogen and boron doped carbon quantum dots and graphene oxide (NBCQDs@GO) which can provide sufficient surface area and enhance the conductivity of the electrode. The O,O-dimethyl OPs class specific antibody mAb3C9 was assembled onto the NBCQDs@GO and the phage-mimotope M31 competitively bound to mAb3C9 with OPs. Furthermore, large amounts of anti-M13 mAb-HRP were introduced to the electrode through thousands of binding sites on the capsid of phage. HRP can catalyze 4-chloro-1-naphthol (4-CN) to produce insoluble precipitates (Benzo-4-chlorhexanedione, 4-CD). Hence, the concentration of OPs can be quantified by measuring impedance signal with electrochemical impedance spectrum (EIS). Under the optimal detection conditions, the 50% inhibitory concentration (IC50) and limits of detection (LODs) values of 9 O,O-dimethyl OPs were in range of 0.989-4.017 ng/mL and 0.003-0.014 ng/mL, respectively. The recovery rates of spiked OPs in cucumber, cabbage and lettuce were 88.20-112.50% with coefficient of variation from 2.97 to 15.64%. Therefore, the immunosensor showed very good sensitivity and demonstrating potential application for the detection of O,O-dimethyl OPs in food samples.

A sensitive ratiometric fluorescent sensor based on carbon dots and CdTe quantum dots for visual detection of biogenic amines in food samples.

A novel dual-emission ratiometric fluorescent sensor for biogenic amines (BAs) was prepared by simple mixing blue fluorescent carbon dots (CDs) and yellow fluorescent CdTe quantum dots (CdTe QDs). Based on different sensitive properties of pH, CdTe QDs and CDs were used as the response signal and internal reference signal, respectively. The developed ratiometric fluorescent sensor achieved quantitative analysis of eight kinds of BAs with rapid response (30 s) and low limits of detection (1.259-5.428 µM). Furthermore, color-tunable fluorescent test strips were constructed by easily assembling CDs and CdTe QDs onto filter paper. The obtained smart label showed a distinguishable fluorescent color variation from blue to green during the corruption of shrimp samples. The smart label with advantages of convenience and rapidness provided a method for visually monitoring the freshness of food samples.

A low-cost and eco-friendly powder catalyst: Iron and copper nanoparticles supported on biochar/geopolymer for activating potassium peroxymonosulfate to degrade naphthalene in water and soil.

A low-cost and environment-friendly biochar/geopolymer composite loaded with Fe and Cu nanoparticles (Fe-Cu@BC-GM) was prepared by impregnation-calcination using lignin and kaolin as precursors. SEM, FTIR and XRD analysis suggested that the Fe-Cu@BC-GM had a certain pore structure, rich functional groups and stable crystal structure. The obtained Fe-Cu@BC-GM was used as the catalyst of potassium peroxymonosulfate (PMS) for remediation of wastewater and soil polluted by naphthalene (NAP). Experimental results indicated that Fe-Cu@BC-GM exhibited outstanding catalytic performance, and the maximum degradation rate of NAP in water and soil reached 98.35% and 67.98% within 120 min, respectively. The XPS measurement confirmed the presence of successive Fe (Ⅲ)/Fe (Ⅱ) and Cu(Ⅱ)/Cu(Ⅰ) redox pairs cycles on the surface of Fe-Cu@BC-GM, which made Fe (Ⅲ) and Cu(Ⅰ) continuously generated Fe (Ⅱ) activating PMS to produce SO4·- and ·OH for the degradation of NAP. The effects of Fe-Cu@BC-GM/PMS system on plant toxicity were evaluated by analyzing the degradation intermediates and bioassay of mung bean. It was proved that the Fe-Cu@BC-GM/PMS system could degrade NAP into less toxic intermediates, and the seed germination rate, root and stem length of mung bean after soil remediation were not notably different from those of the uncontaminated soil. This work opened new prospect for the application of geopolymer in degradation of persistent organic pollutants (POPs) and provided a cost-effective option for the remediation of the persistent organic pollutants contaminated water and soil.

Colorimetric and ratiometric fluorescent dual-mode sensitive detection of Hg2+ based on UiO-66-NH2@Au composite.

A colorimetric and ratiometric fluorescent dual-mode assay is constructed for sensitive and specific Hg2+ sensing based on UiO-66-NH2 and Au composite (UiO-66-NH2@Au). The addition of Hg2+ stimulates the peroxidase-like activity of UiO-66-NH2@Au by the formation of Au-Hg amalgam, promoting the oxidizing of chromogenic substrate OPD to DAP with the aid of H2O2, which lead to the change of colorimetric and fluorescent signals. The absorbance of the sensing system at 450 nm is linear positive correlation with Hg2+ concentration of 30-1400 nM and the color of the solution under visible light shaded from light yellow to dark yellow. With the increase of Hg2+ concentration, the fluorescence signal at 570 nm (DAP) increased whereas that at 455 nm (intrinsic fluorescence of UiO-66-NH2) decreased due to inner filter effect (IFE), the fluorescence intensity ratio (F455/F570) decreasing linearly with Log [Hg2+] over the range 60-1700 nM; the fluorescence emission of sensing system under UV excitation changed from blue to yellow, which can easily be discerned visually. This assay was successfully applied to the determination of Hg2+ in tap water and river water. The results indicate that the colorimetric and ratiometric fluorescent dual-mode assay based on UiO-66-NH2@Au realized visual determination of Hg2+ rapidly and reliably, revealed application prospect in Hg2+ monitoring.

Core-shell structural nitrogen-doped carbon foam loaded with nano zero-valent iron for simultaneous remediation of Cd (II) and NAP in water and soil: Kinetics, mechanism, and environmental evaluation.

An economical, efficient, and environmentally friendly technology was developed for simultaneous remediation of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in soil and water. In this study, using pinecones powder as the precursor, the core-shell structural nitrogen-doped carbon foam loaded with nano zero-valent iron (nZVI@NCF) was synthesized through Mannich reaction and high-temperature carbon reduction. The nZVI@NCF was applied as the adsorbent and catalyst to simultaneously remediate the composite pollutants of Cd (II) and naphthalene (NAP). Under the optimal conditions, the adsorption capacity of Cd (II) in water and soil were 13.9 mg·g-1 and 1.97 mg·g-1, respectively, and the adsorption process conformed to the pseudo-second-order kinetic model. The degradation rates of NAP in water (10 mg·L-1) reached almost 100% as well as it could reach 59.12% in soil (10 mg·kg-1). In addition, it was proved that the presence of NAP could compete with Cd (II) for the active sites on the surface of the material to inhibit the adsorption of Cd (II), while the co-existence of Cd (II) could improve the degradation of NAP by the nZVI@NCF/PMS system due to the nZVI-Cd bimetallic effect and the pro-oxidant effect of Cd (II) promoting the generation of ROS. The free radical quenching experiment revealed that the generated ·O2- was the main substance that mediated the redox of nZVI/Fe2+/Fe3+ to oxidative NAP during the degradation process. Furthermore, the results of the phytotoxicity test demonstrated that the nZVI@NCF/PMS system could effectively remediate the soil co-contaminated with Cd (II) and NAP as well as improve the soil environment quality. This research will provide new materials and potential technologies for the efficient treatment of the composite pollutants in the environment.

Mixed matrix of MOF@COF hybrids for enrichment and determination of phenoxy carboxylic acids in water and vegetables.

A novel mixed matrix of MOF@COF hybrid was firstly formed by coating of hexahedral cage structure MOF with lightweight porous COF, and applied in dispersive solid-phase extraction of the phenoxy carboxylic acids (PCAs) from water and vegetable samples. Combined with liquid chromatography-tandem mass spectrometry, an excellent method with low limits of detection (0.69-1.79 ng·L-1/0.002-0.006 ng·g-1), good reproducibility (1.32%-7.02%/1.81%-6.71%), and excellent linearities (10-1000 ng·L-1, R ≥ 0.9955/0.04-50 ng·g-1, R ≥ 0.9966) was established. The adsorption mechanisms deduced that the π-π interaction, hydrophobic effects, hydrogen bond, and halogen bond may promote the excellent adsorption of the PCAs. Finally, the applicability of the method was verified by spiking four kinds of water and vegetable samples with PCAs, and satisfying recoveries were obtained (between 83.3% and 104.9%).

Efficient removal of Cu-EDTA complexes from wastewater by combined electrooxidation and electrocoagulation process: Performance and mechanism study.

In this study, combined electrooxidation and electrocoagulation (EO-EC) reactor using RuO2-IrO2/Ti and Al electrodes has been built for treatment of Cu-EDTA wastewater. Effects of current density, electrolyte, NaCl concentration, pH and initial concentration on EO-EC performance were investigated. In this study, Cu-EDTA removal efficiency increased with a higher current density. The electrolyte type exerted a significant role in EO-EC process, compared with Na2SO4 and NaNO3, NaCl was a superior supporting electrolyte because the oxidation of Cl- into Cl2 provided additional highly reactive oxidant ClO- for Cu-EDTA oxidation or mineralization. In neutral or alkaline solution, EO-EC reactor performed better than when it was acid. At the condition of current density 10.29 mA cm-2, C0(NaCl) 1 g L-1, C0(Cu) 50 mg L-1 and pH 7, the Cu and COD removal efficiency reached 99.85% and 85.01%, respectively within 60 min. The possible mechanism of Cu-EDTA removal was proposed based on SEM, EDS, XRD, FTIR and XPS analysis of the products. Cu-EDTA chelates were degraded or mineralized by direct charge transfer, chemisorbed M(·OH) and active chorine species produced on anode surface, in which degradation intermediates and mineralization products of Cu-EDTA were generated. Meanwhile, residual degradation intermediates and mineralization products were removed by electrocoagulation. In this study, EO-EC process has been proved to be an effective way for the treatment of Cu-EDTA contaminated wastewater.