Nitrogen doped bimetallic sludge biochar composite for synergistic persulfate activation: Reactivity, stability and mechanisms.

As a recycling use of waste activated sludge (WAS), we used high-temperature pyrolysis of WAS to support bimetallic Fe-Mn with nitrogen (N) co-doping (FeMn@N-S), a customized composite catalyst that activates peroxysulphate (PS) for the breakdown of tetracycline (TC). First, the performance of TC degradation was evaluated and optimized under different N doping, pH, catalyst dosages, PS dosages, and contaminant concentrations. Activating PS with FeMn@N-S caused the degradation of 91% of the TC in 120 min. Next, characterization of FeMn@N-S by XRD, XPS and FT-IR analysis highlights N doping is beneficial to take shape more active sites and reduces the loss of Fe and Mn during the degradation reaction. As expected, the presence of Fe-Mn bimetallic on the catalyst surface increases the rate of electron transfer, promoting the redox cycle of the catalyst. Other functional groups on the catalyst surface, such as oxygen-containing groups, accelerated the electron transfer during PS activation. Free radical quenching and ESR analysis suggest that the main contributor to TC degradation is surface-bound SO4•-, along with the presence of single linear oxygen (1O2) oxidation pathway. Finally, the FeMn@N-S composite catalyst exhibits excellent pH suitability and reusability, indicating a solid practicality of this catalyst in PS-based removal of antibiotics from wastewater.

Silica enhanced activation and stability of Fe/Mn decorated sludge biochar composite for tetracycline degradation.

In this study, SiO2-composited biochar decorated with Fe/Mn was prepared by co-pyrolysis method. The degradation performance of the catalyst was evaluated by activating persulfate (PS) to degrade tetracycline (TC). The effects of pH, initial TC concentration, PS concentration, catalyst dosage and coexisting anions on degradation efficiency and kinetics of TC were investigated. Under optimal conditions (TC = 40 mg L-1, pH = 6.2, PS = 3.0 mM, catalyst = 0.1 g L-1), the kinetic reaction rate constant could reach 0.0264 min-1 in Fe2Mn1@BC-0.3SiO2/PS system, which was 12 times higher than that in the BC/PS system (0.00201 min-1). The electrochemical, X-ray diffractometer (XRD), Fourier transform infrared spectrum (FT-IR) and X-ray photoelectron spectroscopy (XPS) analysis showed that both metal oxides and oxygen-containing functional groups provide more active sites to activate PS. The redox cycle between Fe(II)/Fe(III) and Mn(II)/Mn(III)/Mn(IV) accelerated the electron transfer and sustained the catalytic activation of PS. Radical quenching experiments and electron spin resonance (ESR) measurements confirmed that surface sulfate radical (SO4•-) play a key role in TC degradation. Three possible degradation pathways of TC were proposed based on high-performance liquid chromatography coupled with high-resolution mass spectrometry (HPLC-HRMS) analysis, the toxicity of TC and its intermediates was analyzed by bioluminescence inhibition test. In addition to the enhanced catalytic performance, the presence of silica also improved the stability of the catalyst, as confirmed by cyclic experiment and metal ion leaching analysis. The Fe2Mn1@BC-0.3SiO2 catalyst, derived from low-cost metals and bio-waste materials, offer an environmentally friendly option to design and implement heterogenous catalyst system for pollutant removal in water.

Cationic polyacrylamide (CPAM) enhanced pressurized vertical electro-osmotic dewatering of activated sludge.

Pressurized vertical electro-osmotic dewatering (PVEOD) has been regarded as a feasible method to achieve sludge deep-dewatering, but the dewatering efficiency is still challenged by high electric resistance. This study employed cationic polyacrylamide (CPAM) as a skeleton builder to enhance electro-osmotic flow in PVEOD. The sludge dewatering efficiency and synergistic effect of CPAM and PVEOD were elucidated. The sludge morphology, surface property, extracellular polymeric substances (EPS) destruction and migration, spatial distributions of proteins and polysaccharides, and current changes were investigated. After the addition of optimal CPAM dose, the sludge formed a uniform and porous structure that provided water channels and enhanced electric transport, thus promoting EPS destruction. The sludge moisture content (MC) analysis indicated the more liberation of bound water due to EPS destruction. Besides, the re-flocculation of disintegrated sludge flocs improved the sludge filtration and thus dewaterability. Instantaneous energy consumption (Et,0.5) was optimized and two-step synergistic mechanism was thus proposed. These findings indicated that the combination of CPAM and PVEOD is a promising strategy to broaden the scope of industrial application of sludge deep-dewatering.

[Determination of trace low molecular mass aldehydes in air by ultra-fast liquid chromatography-tandem mass spectrometry].

OBJECTIVE: To establish a rapid and accurate method for the determination of trace acetaldehyde, acrolein, methacrylaldehyde, crotonaldehyde in the air by ultra-fast liquid chromatography-tandem mass spectrometry(UFLC-MS/MS). METHODS: The air sample was concentrated and derivatived by 3-methyl-2(3 H)-benzothiazolonhydrazone(MBTH), and the effect of derivative conditions including the concentration of MBTH, the pH, the derivative time and temperature was investigated. The stability of derivatives, the cracking mechanism of mass spectrometry, the matrix effect of the method and air sampling efficiency were studied. The chromatographic separation was carried out on a Shim-pack XR-ODS II column(100 mm×2. 0 mm, 2. 2 µm) by using water/methanol solution as the mobile phase with the gradient elution. Detection was performed in positive multi-reaction monitoring(MRM) mode for quantification by using external standard method. RESULTS: The four analytes showed good linear relationship within the range of 1. 00-100 µg/L(calculated by aldehyde) with a correlation coefficient r≥0. 9990. The limits of quantitation(LOQs) of the method(concentrated with 10 L air) were 0. 5 µg/m~3 in air, for acetaldehyde, acrolein, methacrylaldehyde, crotonaldehyde. The recoveries of the method were 90. 6%-97. 8% at the three spiked levels, and the relative standard deviations(RSDs) were between 1. 9%-6. 4%(n=6), the average sampling efficiency was between 91. 0%-97. 1%. CONCLUSION: The developed method is simple, less interference and specificity, and is suitable for the simultaneous rapid determination of trace acetaldehyde, acrolein, methacrylaldehyde, crotonaldehyde in air of work place.

Manganese doped iron-carbon composite for synergistic persulfate activation: Reactivity, stability, and mechanism.

The heterogeneous catalytic process has been under development for aqueous pollutant degradation, yet electron transfer efficiency often limits the effectiveness of catalytic reactions. In this study, a novel composite material, manganese doped iron-carbon (Mn-Fe-C), was tailor designed to promote the catalytic electron transfer. The Mn-Fe-C composite, synthesized via a facile carbothermal reduction method, was characterized and evaluated for its performance to activate persulfate (PS) and degrade Rhodamine Blue (RhB) dye under different pH, catalyst dosages, PS dosages, and pollutant concentrations. Electron spin resonance, along with quenching results by ethanol, tert-butanol, phenol, nitrobenzene and benzoquinone, indicated that surface bounded SO4•- was the main contributor for RhB degradation, while the roles of aqueous SO4•- and •OH were very minor. Through characterization by XRD, XPS and FTIR analysis, it was determined that the electron transfer during activation of PS was accelerated by the oxygen functional groups on catalyst surface and the promoted redox cycle of Fe3+ and Fe2+ by Mn. Finally, the Mn-Fe-C composite catalyst exhibited an excellent reusability and stability with negligible leached Fe and Mn ions in solutions. Results of this study provide a promising design for heterogeneous catalysts that can effectively activate PS to remove organic pollutants from water at circumneutral pH conditions.

Retracted: Rapid and effective sample cleanup based on graphene oxide-encapsulated core-shell magnetic microspheres for determination of fifteen trace environmental phenols in seafood by liquid chromatography-tandem mass spectrometry.

This article has been retracted at the request of the Editor after the corresponding author pointed the Editor to comments from an anonymous reader. The article reports electron micrographs of different preparations while showing identical images as used in previous publications by the same authors. The particles in Fig. 4C (SEM image of Fe3O4@SiO2) are identical to each other and the corresponding author confirmed that these have been copy-pasted. In addition, these particles have previously been communicated as different substances in Fig. 1B from Pan et al., J. Mater. Chem. A, 2015,3, 23042-23052 (DOI: 10.1039/C5TA05840F) and Fig. 3F from Pan et al., Anal. Methods, 2017,9, 5281-5292 (DOI: 10.1039/C7AY01444A). Furthermore, the curves in Fig. 7, especially the baseline, shows a remarkable similarity to Fig. 8 from Pan et al., J. Mater. Chem. A, 2015,3, 23042-23052 (DOI: 10.1039/C5TA05840F) and Fig. 5F from Pan et al., J. Mater. Chem. A, 2014,2, 15345-15356 (DOI: 10.1039/c4ta02600d). The manipulation of images and data in this way is a serious offense to the integrity of the scientific community and casts doubts on all the data, and accordingly also the conclusions based on that data, in this publication. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process. This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal).

Understanding Mechanisms of Synergy between Acidification and Ultrasound Treatments for Activated Sludge Dewatering: From Bench to Pilot-Scale Investigation.

Enhancing activated sludge dewaterability is of scientific and engineering importance in the face of accelerated urbanization and stringent environmental regulations. In this study, we investigated the integration of acidification and ultrasound (A/US) treatment for improving sludge dewaterability at both bench- and pilot-scales. Our results showed that the A/US process exhibited significantly improved sludge dewatering performance, characterized by capillary suction time, cake moisture, and water/solid content of sludge cake. Synergistic dewatering mechanisms were elucidated with a suite of macro and spectroscopic evidence. Characterization of treated sludge revealed that US-induced thermal, mechanical shearing force, and radical oxidation effects disrupts floc cells and accelerates the decomposition of extracellular polymeric substances (EPS), releasing bound water into the bulk phase. In addition to enhancing hydrolysis of EPS, the acidic pH environment caused the protonation of functional groups on EPS, facilitating the reflocculation of US decomposed sludge for improved filterability. Our bench-scale and pilot-scale investigations provide a mechanistic basis for better understanding of the A/US process, and enable development of a viable and economical dewatering technology.

Synergetic pretreatment of waste activated sludge by hydrodynamic cavitation combined with Fenton reaction for enhanced dewatering.

The dewatering of waste activated sludge by integrated hydrodynamic cavitation (HC) and Fenton reaction was explored in this study. We first investigated the effects of initial pH, sludge concentration, flow rate, and H2O2 concentration on the sludge dewaterability represented by water content, capillary suction time and specific resistance to filtration. The results of dewatering tests showed that acidic pH and low sludge concentration were favorable to improve dewatering performance in the HC/Fenton system, whereas optimal flow rate and H2O2 concentration applied depended on the system operation. To reveal the synergism of HC/Fenton treatment, a suite of analysis were implemented: three-dimensional excitation emission matrix (3-DEEM) spectra of extracellular polymeric substances (EPS) such as proteins and polysaccharides, zeta potential and particle size of sludge flocs, and SEM/TEM imaging of sludge morphology. The characterization results indicate a three-step mechanism, namely HC fracture of different EPS in sludge flocs, Fenton oxidation of the released EPS, and Fe(III) re-flocculation, that is responsible for the synergistically enhanced sludge dewatering. Results of current study provide a basis to improve our understanding on the sludge dewatering performance by HC/Fenton treatment and possible scale-up of the technology for use in wastewater treatment plants.

Comparison of the reactivity of ibuprofen with sulfate and hydroxyl radicals: An experimental and theoretical study.

Hydroxyl radical (•OH) and sulfate radical anion (SO4•-) based advanced oxidation technologies (AOTs) are effective methods to treat trace organic contaminants (TrOCs) in engineered waters. Although both technologies result in the same overall removal of TrOCs, the mechanistic differences between these two radicals involved in the oxidation of TrOCs remain unclear. In this study, we experimentally examined the degradation kinetics of neutral ibuprofen (IBU), a representative TrOC, by •OH and SO4•- at pH3 in UV/H2O2 and UV/persulfate systems, respectively. The second-order rate constants (k) of IBU with •OH and SO4•- were determined to be 3.43±0.06×109 and 1.66±0.12×109M-1s-1, respectively. We also theoretically calculated the thermodynamic and kinetic behaviors for reactions of IBU with •OH and SO4•- using the density functional theory (DFT) M06-2X method with 6-311++G** basis set. The results revealed that H-atom abstraction is the most favorable pathway for both •OH and SO4•-, but due to the steric hindrance SO4•- exhibits significantly higher energy barriers than •OH. The theoretical calculations corroborate our experimental observation that SO4•- has a smaller k value than •OH in reacting with IBU. These comparative results are of fundamental and practical importance in understanding the electrophilic interactions between radicals and IBU molecules, and to help select preferred radical oxidation processes for optimal TrOCs removal in engineered waters.

Rapid decolorization of dye Orange G by microwave enhanced Fenton-like reaction with delafossite-type CuFeO2.

Bimetallic oxide CuFeO2 as a new heterogeneous catalyst has shown much higher catalytic ability for activating peroxide than single-metal oxides. The present work demonstrated a synergistic microwave (MW) enhanced Fenton-like process with CuFeO2 for rapid decolorization of azo dye Orange G (OG). The MW irradiation dramatically enhanced the OG degradation efficiency, achieving 99.9% decolorization within 15min at pH5. The XRD analysis of reused CuFeO2, together with metal leaching tests, indicated merits of recycling for CuFeO2. The subsequent surface element analysis by XPS for fresh and used CuFeO2 showed a complex network for reactions between copper-iron redox pairs and surface hydroxyl groups, leading to a synergistic Fenton-like system accelerated by MW irradiation. In the CuFeO2 initiated Fenton-like reactions, several oxidant species (i.e., OH, O2-, electron hole, and FeIVO) responsible to the OG oxidation were identified by quenching experiments, showing the MW generated high temperature and "hot spots" enhanced the yield of OH by generation of electron-hole pairs. Further, the 26 detected degradation products confirmed the OH dominant oxidation of OG. This study shows that the MW-enhanced Fenton-like reaction using CuFeO2 has potential applications for rapid decolorization of dye effluent.

Planar graphene oxide-based magnetic ionic liquid nanomaterial for extraction of chlorophenols from environmental water samples coupled with liquid chromatography-tandem mass spectrometry.

A planar graphene oxide-based magnetic ionic liquid nanomaterial (PGO-MILN) was synthesized. The prepared PGO-MILN was characterized by transmission electronmicroscopy (TEM) and Fourier-transform infrared spectrometry (FTIR). The results of adsorption experiments showed that the PGO-MILN had great adsorption capacity for 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP) and pentachlorophenol (PCP). Based on the adsorption experimental data, a sensitive magnetic method for determination of the five CPs in environmental water samples was developed by an effective magnetic solid-phase extraction (MSPE) procedure coupled with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The effects of main MSPE parameters including the solution pH, extraction time, desorption time, and volume of desorption solution on the extraction efficiencies had been investigated in detail. The recoveries ranged from 85.3 to 99.3% with correlation coefficients (r) higher than 0.9994 and the linear ranges were between 10 and 500ngL(-1). The limits of detection (LODs) and limits of quantification (LOQs) of the five CPs ranged from 0.2 to 2.6ngL(-1) and 0.6 to 8.7ngL(-1), respectively. The intra- and inter- day relative standard deviations (RSDs) were in the range from 0.6% to 7.4% and from 0.7% to 8.4%, respectively. It was confirmed that the PGO-MILN was a kind of highly effective MSPE materials used for enrichment of trace CPs in the environmental water.

Rapid analysis of six trace trichlorophenols in seawater by magnetic micro-solid-phase extraction and liquid chromatography with tandem mass spectrometry.

A new facile, rapid, inexpensive, and sensitive method for the analysis of six trace trichlorophenols in seawater samples was developed by magnetic micro-solid-phase extraction coupled to liquid chromatography with tandem mass spectrometry. Core-shell covalently functionalized ferroferric oxide coated with aminated silicon dioxide and decorated with multiwalled carbon nanotubes was applied as an adsorbent to perform the extraction process. The effect of factors including solution pH, contact time, adsorbent amount, and ionic strength were investigated in detail. The obtained results revealed that the proposed adsorbent was a highly effective and low-cost magnetic micro-solid-phase extraction material for the enrichment of 2,3,4-trichlorophenol, 2,3,5-trichlorophenol, 2,3,6-trichlorophenol, 2,4,5-trichlorophenol, 2,4,6-trichlorophenol, and 3,4,5-trichlorophenol from seawater. Under the optimized conditions, the recoveries ranged from 88.0 to 99.5% at the three spiking levels, the limits of detection and the limits of quantification were 0.002 and 0.007 µg/L for the six trichlorophenols, respectively. The intra- and interday relative standard deviations were 2.0-6.7 and 4.5-8.9%, respectively. The calibration curves showed a good linearity in the range of 0.02-5.0 µg/L. The routine run analyses showed that the developed method was fast, simple, accurate, solvent-saving and high resolution, and it was suitable for the determination of trace trichlorophenols in seawater.

Rapid and effective sample cleanup based on graphene oxide-encapsulated core-shell magnetic microspheres for determination of fifteen trace environmental phenols in seafood by liquid chromatography-tandem mass spectrometry.

In this study, graphene oxide-encapsulated core-shell magnetic microspheres (GOE-CS-MM) were fabricated by a self-assemble approach between positive charged poly(diallyldimethylammonium) chloride (PDDA)-modified Fe3O4@SiO2 and negative charged GO sheets via electrostatic interaction. The as-prepared GOE-CS-MM was carefully characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer analysis (VSM), and X-ray photoelectron spectroscopy (XPS), and was used as a cleanup adsorbent in magnetic solid-phase extraction (MSPE) for determination of 15 trace-level environmental phenols in seafood coupled to liquid chromatography-tandem mass spectrometry (LC-MS/MS). The obtained results showed that the GOE-CS-MM exhibited excellent cleanup efficiency and could availably reduce the matrix effect. The cleanup mechanisms were investigated and referred to π-π stacking interaction and hydrogen bond between GOE-CS-MM and impurities in the extracts. Moreover, the extraction and cleanup conditions of GOE-CS-MM toward phenols were optimized in detail. Under the optimized conditions, the limits of detection (LODs) were found to be 0.003-0.06 µg kg(-1), and satisfactory recovery values of 84.8-103.1% were obtained for the tested seafood samples. It was confirmed that the developed method is simple, fast, sensitive, and accurate for the determination of 15 trace environmental phenols in seafood samples.

Sono-advanced Fenton decolorization of azo dye Orange G: Analysis of synergistic effect and mechanisms.

In this study, a successful decolorization of Orange G was achieved by means of coupling zero valent iron (ZVI), H2O2 and ultrasound (US) under acidic pH conditions. The synergistic effect and characterization of potential roles of the factors including ZVI, tert-Butanol as radical scavenger, dissolved ferrous ions and H2O2 generated from sonication were evaluated in this sono-advanced Fenton process (SAFP) system. A clear synergy was evident in terms of decolorization rate and the TOC removal as the input of US enhanced the activity of the Fe(0)/H2O2 system. The results suggested that the ZVI was potential replacement for the Fe(2+) ion. This remarkable activity was attributed to the capacity of Fe(2+) formed and reduction of sonic-dissolved Fe(2+) concentration by the formation of {Fe·Fe(2+)}. The modification of the condition of H2O2 addition such as the dosage and input method showed significant variations in terms of decolorization rate. This result indicated that the optimal external addition of H2O2 and input method is a limited factor of decolorization rate due to its comparatively insufficient generated by ultrasound.

Decolorization of azo dyes Orange G using hydrodynamic cavitation coupled with heterogeneous Fenton process.

The present work demonstrates the application of the combination of hydrodynamic cavitation (HC) and the heterogeneous Fenton process (HF, Fe(0)/H2O2) for the decolorization of azo dye Orange G (OG). The effects of main affecting operation conditions such as the inlet fluid pressure, initial concentration of OG, H2O2 and zero valent iron (ZVI), the fixed position of ZVI, and medium pH on decolorization efficiency were discussed with guidelines for selection of optimum parameters. The results revealed that the acidic conditions are preferred for OG decolorizaiton. The decolorization rate increased with increasing H2O2 and ZVI concentration and decreased with increasing OG initial concentration. Besides, the decolorization rate was strongly dependent on the fixed position of ZVI. The analysis results of degradation products using liquid chromatography-ESI-TOF mass spectrometry revealed that the degradation mechanism of OG proceeds mainly via reductive cleavage of the azo linkage due to the attack of hydroxyl radical. The present work has conclusively established that the combination of HC and HF can be more energy efficient and gives higher decolorization rate of OG as compared with HC and HF alone.

Double-sided magnetic molecularly imprinted polymer modified graphene oxide for highly efficient enrichment and fast detection of trace-level microcystins from large-volume water samples combined with liquid chromatography-tandem mass spectrometry.

Microcystins (MCs), a group of cyclic heptapeptide heaptoxins and tumor promoters, are generated by cyanobacteria occurring in surface waters, such as eutrophic lakes, rivers, and reservoirs. In this present study, a novel double-sided magnetic molecularly imprinted polymer modified graphene oxide (DS-MMIP@GO) based magnetic solid-phase extraction (MSPE) method was developed for fast, effective and selective enrichment, and recognition of trace MCs in environmental water samples combined with high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The synthesized novel DS-MMIP@GO was used as the adsorbents in this work and was carefully characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and Raman spectra. The adsorption and desorption conditions of DS-MMIP@GO toward MCs were optimized in detail to obtain the highest binding capacity, selectivity, and release efficiency. Under the optimum conditions, the enrichment factors of the method for eight target MCs were found to be 2000. The limits of quantitation (LOQs) of the method for eight MCs were in range of 0.1-2.0ngL(-1). The double-sided MMIP modified structure provided DS-MMIP@GO with abundant adsorption sites and permitted it to exhibit excellent enrichment and selectivity toward trace-level MCs. The proposed method was successfully applied for the analysis of environmental water samples with recoveries ranging from 84.1 to 98.2%. Compared to conventional methods for MCs detection reported in literatures, the one developed in this work based on DS-MMIP@GO and LC-MS/MS showed much faster, more sensitive, and more convenient.

Designing and characterizing a multi-stepped ultrasonic horn for enhanced sonochemical performance.

The commonly used ultrasonic horn generates localized cavitation below its converging tip resulting in a dense bubble cloud near the tip and limiting diffusion of reactive components into the bubble cloud or reactive radicals out of the bubble cloud. To improve contact between reactive components, a novel ultrasonic horn design was developed based on the principles of the dynamic wave equation. The horn, driven at 20 kHz, has a multi-stepped design with a cone-shaped tip increasing the energy-emitting surface areas and creating multiple reactive zones. Through different physical and chemical experiments, performance of the horn was compared to a typical horn driven at 20 kHz. Hydrophone measurements showed high acoustic pressure areas around the horn neck and tip. Sonochemiluminescence experiments verified multiple cavitation zones consistent with hydrophone readings. Calorimetry and dosimetry results demonstrated a higher energy efficiency (31.3%) and a larger hydroxyl radical formation rate constant (0.36 µM min(-1)) compared to typical horns. In addition, the new horn degraded naphthalene faster than the typical horn tested. The characterization results demonstrate that the multi-stepped horn configuration has the potential to improve the performance of ultrasound as an advanced oxidation technology by increasing the cavitation zone in the solution.

Amine-functional magnetic polymer modified graphene oxide as magnetic solid-phase extraction materials combined with liquid chromatography-tandem mass spectrometry for chlorophenols analysis in environmental water.

A novel planar-structure amine-functional magnetic polymer modified graphene oxide nanocomposite (NH2-MP@GO) was synthesized. The properties were characterized by transmission electron microscopy (TEM) and Fourier-transform infrared spectrometry (FTIR). The obtained adsorption results showed that the NH2-MP@GO had great adsorptive ability toward five chlorophenols (CPs), including 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP) and pentachlorophenol (PCP). Based on these, an effective magnetic solid-phase extraction (MSPE) procedure coupled with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the preconcentration and determination of the five CPs in environmental water samples was developed. Various experimental parameters that could affect the extraction efficiencies had been investigated in detail. Under the optimum conditions, the enrichment factors of the method for the target CPs were found to be 1000. The proposed method was successfully applied for the analysis of environmental water samples with recoveries ranging from 86.4 to 99.8% with correlation coefficients (R) higher than 0.9994. Good linearities were obtained ranging from 10 to 500ng/L for 2-CP, 5 to 500ng/L for 2,4-DCP, 2 to 500ng/L for 2,4,6-TeCP and 2,3,4,6-TeCP, and 1 to 500ng/L for PCP, respectively. The limits of quantitation for the five CPs were 0.6-9.2ng/L. It was confirmed that the planar-structure NH2-MP@GO was a kind of highly effective MSPE materials used for the trace CPs analyses.

Novel amphiphilic polymeric ionic liquid-solid phase micro-extraction membrane for the preconcentration of aniline as degradation product of azo dye Orange G under sonication by liquid chromatography-tandem mass spectrometry.

A novel amphiphilic polymeric ionic liquid membrane containing a hydrophilic bromide anion and a hydrophobic carbonyl group was synthesized in dimethylformamide (DMF) systems using the ionic liquid 1-butyl-3-vinylimidazolium bromide (BVImBr) and the methylmethacrylate (MMA) as monomers. The prepared amphiphilic ploy-methylmethacrylate-1-butyl-3-vinylimidazolium bromide (MMA-BVImBr) was characterized by a scanning electron microscope and an infrared spectrum instrument. The results of solid-phase micro-extraction membrane (SPMM) experiments showed that the adsorption capacity of membrane was about 0.76µgµg(-1) for aniline. Based on this, a sensitive method for the determination of trace aniline, as a degradation product of azo dye Orange G under sonication, was developed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The calibration curve showed a good linearity ranging from 0.5 to 10.0µgL(-1) with a correlation coefficient value of 0.9998. The limit of quantification was 0.5µgL(-1). The recoveries ranged from 90.6% to 96.1%. The intra- and inter-day relative standard deviations were less than 8.3% and 10.9%. The developed SPMM-LC-MS/MS method was used successfully for preconcentration of trace aniline produced during the sonication of Orange G solution.