Credible and Facile Fluorometric Detection of Soybean Trypsin Inhibitor Activity with a Water-Soluble Poly(diphenylacetylene) Derivative

Herein,a novel method for fl uorometric detection of soybean trypsin inhibitor(SBTI)activity based on a water-soluble poly(diphenylacetylene)derivative was reported.Fluorescence quenching of the polymer via p-nitroaniline,produced from the trypsin-catalyzed decomposition of N-benzoyl-DL-arginine-4-nitroanilide hydrochloride(L-BAPA),was well described using the Stern-Volmer equation.SBTI activity was quantitatively assessed based on changes in the fl uorescence intensity of the polymer.This strategy has several advantages,such as high sensitivity and ease of operation.Moreover,its applicability to other biochemical analyses is promising.

Influence of MnO_(x)deposition on TiO_(2)nanotube arrays for electrooxidation

TiO_(2)has demonstrated outstanding performance in electrochemical advanced oxidation processes(EAOPs)due to its structural stability and high oxygen overpotential.However,there is still much room for improving its electrochemical activity.Herein,narrow bandgap manganese oxide(MnO_(x))was composited with TiO_(2)nanotube arrays(TiO_(2)NTAs)that in-situ oxidized on porous Ti sponge,forming the MnO_(x)-TiO_(2)NTAs anode.XANES and XPS analysis further proved that the composition of MnO_(x)is Mn2O3.Electrochemical characterizations revealed that increasing the composited concentration of MnO_(x)can improve the conductivity and reduce oxygen evolution potential so as to improve the electrochemical activity of the composited MnO_(x)-TiO_(2)NTAs anode.Meanwhile,the optimal degradation rate of benzoic acid(BA)was achieved using MnO_(x)-TiO_(2)NTAs with a MnO_(x)concentration of 0.1 mmol L^(-1),and the role of MnO_(x)was proposed based on DFT calculation.Additionally,the required electrical energy(EE/O)to destroy BA was optimized by varying the composited concentration of MnO_(x)and the degradation voltage.These quantitative results are of great significance for the design and application of high-performance materials for EAOPs.

Structural parameter optimization for novel internal-loop iron–carbon micro-electrolysis reactors using computational fluid dynamics

It is generally recognized that internal-loop reactors are well-developed mass and heat-transfer multiphase flow reactors. However, the internal flow field in the internal-loop reactor is influenced by the structure parameter of the reactor, which has a great effect on the reaction efficiency. In this study, the computational fluid dynamics simulation method was used to determine the influence of reactor structure on flow field, and a volume-offluid model was employed to simulate the gas–liquid, two-phase flow of the internal-loop micro-electrolysis reactor. Hydrodynamic factors were optimized when the height-to-diameter ratio was 4:1, diameter ratio was9:1, draft-tube axial height was 90 mm. Three-dimensional simulations for the water distributor were carried out, and the results suggested that the optimal conditions are as follows: the number of water distribution pipes was four, and an inhomogeneous water distribution was used. According to the results of the simulation,the suitable structure can be used to achieve good fluid mechanical properties, such as the good liquid circulation velocity and gas holdup, which provides a good theoretical foundation for the application of the reactor.

Polyoxometalates coupled covalent organic frameworks as highly active photothermal nanoreactor for CO_(2)cycloaddition

Covalent organic frameworks(COFs)-based nanoreactors have attracted broad interest in many fields due to their voidconfinement effects.However,the inherent drawback of conventional nanoreactors is the lack of internal active sites,which limits their widespread utilization.Herein,we report the construction of hierarchical COF(EB-TFP)nanoreactor with pre-synthesized polyoxometalates(POM,[PV_(2)W_(10)O_(40)]^(5–)(PV_(2)W_(10)))clusters encapsulated inside of COF(POM@COF).PV_(2)W_(10)@EB-TFP anchors nucleophilic-group(Br–ions)and PV_(2)W_(10)anion cluster within the COF framework via electrostatic interactions,which not only simplifies the reaction system but also enhances catalytic efficiency.The reaction performance of the PV_(2)W_(10)@EB-TFP nanoreactor can be tuned to achieve excellent catalytic activity in CO_(2)cycloaddition reaction(CCR)for~97.63%conversion and~100%selectivity under visible light irradiation.A mechanistic study based on density functional theory(DFT)calculations and insitu characterization was also carried out.In summary,we have reported a method for achieving the uniform dispersion of POM single clusters into COF nanoreactor,demonstrating the potential of POM@COF nanoreactor for synergistic photothermal catalytic CO_(2)cycloaddition.

Can perfluorooctanoic acid be effectively degraded usingβ-PbO_(2)reactive electrochemical membrane?

Aqueous perfluorooctanoic acid(PFOA)elimination has raised significant concerns due to its persistence and bioaccumulation.Althoughβ-PbO_(2)plate anodes have shown efficient mineralization of PFOA,it remains unclear whether PFOA can be effectively degraded usingβ-PbO_(2)reactive electrochemical membrane(REM).Herein,we assessed the performance of Ti/SnO_(2)-Sb/La-PbO_(2)REM for PFOA removal and proposed a possible degradation mechanism.At a current density of 10 mA/cm2and a membrane flux of 8500(liters per square meter per hour,LMH),the degradation efficiency of 10 mg/L PFOA was merely8.8%,whereas the degradation efficiency of 0.1 mg/L PFOA increased to 96.6%.Although the porous structure of theβ-PbO_(2)REM provided numerous electroactive sites for PFOA,the generated oxygen bubbles in the pores could block the pore channels and adsorb PFOA molecules.These hindered the protonation process and significantly impeded the degradation of high-concentration PFOA.Quenching experiments indicated that·OH played dominant role in PFOA degradation.The electrical energy per order to remove 0.1 mg/L PFOA was merely 0.74 Wh/L,which was almost an order of magnitude lower than that of other anode materials.This study presents fresh opportunities for the electrochemical degradation of low-concentration PFOA usingβ-PbO_(2)REM.

Photodegradation of hydroxyfluorenes in ice and water: A comparison of kinetics, effects of water constituents, and phototransformation by-products

The photochemical behavior of organic pollutants in ice is poorly studied in comparison to aqueous photochemistry.Here we report a detailed comparison of ice and aqueous photodegradation of two representative OH-PAHs,2-hydroxyfluorene(2-OHFL)and 9-hydroxyfluorene(9-OHFL),which are newly recognized contaminants in the wider environment including colder regions.Interestingly,their photodegradation kinetics were clearly influenced by whether they reside in ice or water.Under the same simulated solar irradiation(λ>290 nm),OHFLs photodegraded faster in ice than in equivalent aqueous solutions and this was attributed to the specific concentration effect caused by freezing.Furthermore,the presence of dissolved constituents in ice also influenced photodegradation with 2-OHFL phototransforming the fastest in‘seawater’ice(k=(11.4±1.0)×10^(−2) min^(−1))followed by‘pure-water’ice((8.7±0.4)×10^(−2) min^(−1))and‘freshwater’ice((8.0±0.7)×10^(−2) min^(−1)).The presence of dissolved constituents(specifically Cl^(−),NO_(3)^(−),Fe(Ⅲ)and humic acid)influences the phototransformation kinetics,either enhancing or suppressing phototransformation,but this is based on the quantity of the constituent present in the matrixes,the specific OHFL isomer and the matrix type(e.g.,ice or aqueous solution).Careful derivation of key photointermediates was undertaken in both ice and water samples using tandem mass spectrometry.Ice phototransformation exhibited fewer by-products and‘simpler’pathways giving rise to a range of hydroxylated fluorenes and hydroxylated fluorenones in ice.These results are of importance when considering the fate of PAHs and OH-PAHs in cold regions and their persistence in sunlit ice.

Degradation and detoxification mechanisms of organophosphorus flame retardant tris(1,3-dichloro-2-propyl)phosphate(TDCPP)during electrochemical oxidation process

Electrochemical oxidation of aqueous tris(1,3-dichloro-2-propyl)phosphate(TDCPP)by using Ti/SnO_(2)-Sb/La-PbO_(2)as anode was investigated for the first time,and the degradation mechanisms and toxicity changes of the degradation intermediates were further determined.Results suggested that electrochemical degradation of TDCPP followed pseudo-first-order kinetics,and the reaction rate constant(k)was 0.0332 min^(−1)at the applied current density of 10 mA/cm^(2)and Na_(2)SO_(4)concentration of 10 mmol/L.There was better TDCPP degradation performance at higher current density.Free hydroxy radical(•OH)was proved to play dominant role in TDCPP oxidation via quenching experiment,with a relative contribution rate of 60.1%.A total of five intermediates(M1,C_(6)H_(11)Cl_(4)O_(4)P;M2,C_(3)H_(7)Cl_(2)O_(4)P;M3,C_(9)H_(16)Cl_(5)O_(5)P;M4,C_(9)H_(14)Cl_(5)O_(6)P;M5,C_(6)H_(10)Cl_(3)O_(6)P)were identified,and the intermediates were further degraded prolonging with the reaction time.Flow cytometer results suggested that the toxicity of TDCPP and degradation intermediates significantly reduced,and the detoxification efficiency was achieved at 78.1%at 180 min.ECOSAR predictive model was used to assess the relative toxicity of TDCPP and the degradation intermediates.The EC_(50)to green algae was 3.59 mg/L for TDCPP,and the values raised to 84,574,54.6,391,and 8920 mg/L for M1,M2,M3,M4,and M5,respectively,indicating that the degradation intermediates are less toxic or not toxic.Electrochemical advanced oxidation process is a valid technology to degrade TDCPP and pose a good detoxification effect.

Preliminary report on methane emissions from the Three Gorges Reservoir in the summer drainage period

Recently reported summertime methane （CH4） emissions （6.7 ± 13.3 mg CH4/（m2·hr）） from newly created marshes in the drawdown area of the Three Gorges Reservoir （TGR）, China have triggered broad concern in academic circles and among the public. The CH4 emissions from TGR water surfaces and drawdown areas were monitored from 3rd June to 16th October 2010 with floating and static chambers and gas chromatography. The average CH4 emission flux from permanently flooded areas in Zigui, Wushan and Yunyang Counties was （0.33 ± 0.09） mg CH4/（m2·hr）. In half of these hottest months of the year, the wilderness, cropland and deforested drawdown sites were aerobic and located above water level, and the CH4 emissions were very small, ranging from a sink at 0.12 mg CH4/（m2·hr） to a source at 0.08 mg CH4/（m2·hr） except for one mud-covered site after flood. Mean CH4 emission in flooded drawdown sites was 0.34 mg CH4/（m2·hr）. The emissions from the rice paddy sites in the drawdown area were averaged at （4.86 ± 2.31） mg CH4/（m2·hr）. Excepting the rice-paddy sites, these results show much lower emission levels than previously reported. Our results indicated considerable spatial and temporal variation in CH4 emissions from the TGR. Human activities and occasional events, such as flood, may also affect emission levels. Long-term CH4 measurements and modeling in a large region are necessary to accurately estimate greenhouse gas emissions from the TGR.

Effects of environmental factors on sulfamethoxazole photodegradation under simulated sunlight irradiation: Kinetics and mechanism

To advance the knowledge of the environmental fate of sulfamethoxazole （SMX）, we systematically investigated the effects of natural water constituents and synthetic substances （i.e., TiO2 nanoparticles （nTiO2） and Ti-doped ^-Bi203 （NTB）） on the photodegradation kinetics of SMX under xenon lamp irradiation. The photolysis of SMX in aqueous solution followed first-order kinetics. Our results showed that higher concentrations of SMX, fulvic acid, suspended sediments, NTB and higher pH value decreased the photodegradation rates of SMX, whereas H202 improved the SMX photodegradation. TiO2 nanoparticles had a dual effect on pbotodegradation due to their photocatalytic activity and photoabsorption of photons. No intermediates more toxic toward Vibrio fischeri than SMX were produced after direct photolysis and photocatalytic degradation for 3 hr. The photolysis of SMX involved three pathways： hydroxylation, cleavage of the sulfonamide bond, and fragmentation of the isoxazole ring. This study lays the groundwork for a better understanding of the environmental fate of SMX.

Insights into the electrochemical degradation of sulfamethoxazole and its metabolite by Ti/SnO_(2)-Sb/Er-PbO_(2) anode

Electrochemical degradation of sulfamethoxazole(SMX)and its metabolite acetyl-sulfamethoxazole(AcSMX)by Ti/SnO_(2)-Sb/Er-PbO_(2) were investigated.Results indicated that the electrochemical degradation of SMX and Ac-SMX followed pseudo-first-order kinetics.The rate constants of SMX and Ac-SMX were 0.268 and 0.072 min-1 at optimal curre nt density of 10 and 14 mA/cm^(2),respectively.Transformation products of SMX and Ac-SMX were identified and the possible degradation pathways,including the cleavage of S-N bond,opening ring of isoxazole and nitration of amino group,were proposed.Total organic carbon removal of SMX was nearly 63.2%after 3 h electrochemical degradation.22.4%nitrogen of SMX was trans formed to NO_(3)-,and 98.8%sulfur of SMX was released as SO_(4)2-.According to quantitative structureactivity relationship model,toxicities of SMX and Ac-SMX to aquatic organisms significantly decreased after electrochemical degradation.Electric energy consumption for 90%SMX and Ac-SMX degradation was determined to be 0.58-8.97 and 6.88-44.19 Wh/L at different experimental conditions,respectively.Compared with parent compound SMX,the metabolite Ac-SMX is more refractory and toxic,which emphasizes the importance of taking its metabolites into account when investigating the disposal of pharmaceuticals from wastewater.

A high activity of Ti/SnO_2-Sb electrode in the electrochemicaldegradation of 2,4-dichlorophenol in aqueous solution

Electrochemicaldegradation of2,4-dichlorophenol （2,4-DCP） in aqueous solutionwas investigated over Ti/SnO2-Sb anode. The factors influencing thedegradation rate, such as applied currentdensity （2-40 mA/cm2 ）, pH （3-11） and initial concentration （5-200 mg/L）were evaluated. Thedegradation of2,4-DCP followed apparent pseudo first-order kinetics. Thedegradation ratio on Ti/SnO2 -Sb anode attained 〉 99.9% after 20 min of electrolysis at initial 5-200 mg/L concentrations at a constant currentdensity of 30 mA/cm2 with a 10 mmol/L sodium sulphate （Na2SO4 ） supporting electrolyte solution. The results showed that 2,4-DCP （100 mg/L）degradation and total organic carbon （TOC） removal ratio achieved 99.9% and 92.8%, respectively, at the optimal conditions after 30 min electrolysis. Under this condition, thedegradation rate constant （k） and thedegradation half-life （t1/2 ）were 0.21 min1 and （2.8 ± 0.2） min, respectively. Mainly carboxylic acids （propanoic acid, maleic acid, propanedioic acid, acetic acid and oxalic acid） weredetected as intermediates. The energy efficiencies for2,4-DCPdegradation （5-200 mg/L）with Ti/SnO2-Sb anode ranged from 0.672 to 1.602 g/kWh. The Ti/SnO2-Sb anodewith a high activity to rapid organic oxidation could be employed todegrade chlorophenols, particularly2,4-DCP inwastewater.

Sm-doped g-C_(3)N_(4)/Ti_(3)C_(2) MXene heterojunction for visible-light photocatalytic degradation of ciprofloxacin

A heterojunction of Sm-doped g-C_(3)N_(4)/Ti_(3)C_(2) MXene(SCN/MX)was constructed via prepolymerization and solid mixture-calcination method.The modified g-C_(3)N_(4) presented a hollow porous seaweed-like shape which can increase its specific area and active sites.In SCN/MX composite,the optical properties,no matter optical absorption ability or separation performance of photo-induced electrons and holes,were enhanced.Among them,Sm-doping may play an important role on transferring the photogenerated electrons to suppress their recombination,and Ti_(3)C_(2) MXene would broaden light absorption and further improve the carrier migration efficiency.The SCN/MX presented higher photocatalytic degradation efficiency(>99%)of cipro floxacin under visible light irradiation.The quenching experiments and electron spin-resonance spectroscopy confirmed that the dominated active materials were superoxide radical and holes.The degradation mechanisms of ciprofloxacin(CIP)over the SCN/MX were attacking of the active materials on the piperazine ring and quinolone ring,and the final products were CO_(2),H_(2)O and F^(-).

Fabrication of Cu/rGO/MoS2 nanohybrid with energetic visible-light response for degradation of rhodamine B

A novel visible-light-driven Cu/rGO/MoS2(CRM) ternary nanostructure as a photocatalyst with high catalytic activity towards environmental purification using solar energy was successfully synthesized through a facile solvothermal method.It was found that the nanoflower structure of MoS2 increased the number of its exposed edges.Meanwhile rGO as a catalytic substrate played a role of charge-carrier channel to improve the separation of holes and electrons,which originated from the band gap absorption of MoS2.The content of Cu in photocatalyst affected photocatalytic performance obviously.And the optimal 30% Cu/rGO/MoS2 possessed the highest photocatalytic performance,which could be attributed to the improved separation of charges and synergistic effects among Cu,rGO and MoS2.The removal efficiency of Rhodamine B(RhB) over CRM was up to 100% in 5 min.CRM as a photocatalyst maintained good reproducibility and stability during 3 times of the recycle experiments.These results indicate CRM is a promising photocatalyst for degrading organic pollutants in wastewater.

Electro-oxidation of Ni(Ⅱ)-citrate complexes at BDD electrode and simultaneous recovery of metallic nickel by electrodeposition

The simultaneous electro-oxidation of Ni(Ⅱ)-citrate and electrodeposition recovery of nickel metal were attempted in a combined electro-oxidation-electrodeposition reactor with a boron-doped diamond(BDD)anode and a polished titanium cathode.Effects of initial nickel citrate concentration,current density,initial p H,electrode spacing,electrolyte type,and initial electrolyte dosage on electrochemical performance were examined.The efficiencies of Ni(Ⅱ)-citrate removal and nickel metal recovery were determined to be 100%and over 72%,respectively,under the optimized conditions(10 m A/cm^(2),pH 4.09,80 mmol/L Na_(2)SO_(4),initial Ni(Ⅱ)-citrate concentration of 75 mg/L,electrode spacing of 1 cm,and 180 min of electrolysis).Energy consumption increased with increased current density,and the energy consumption was 0.032 kWh/L at a current density of 10 m A/cm^(2)(pH 6.58).The deposits at the cathode were characterized by scanning electron microscopy(SEM),energy-dispersive spectrometry(EDS),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).These characterization results indicated that the purity of metallic nickel in cathodic deposition was over 95%.The electrochemical system exhibited a prospective approach to oxidize metal complexes and recover metallic nickel.

Synchronous mineralization of three aqueous non-steroidal anti-inflammatory drugs in electrochemical advanced oxidation process

Electrochemical degradation performances of three non-steroidal anti-inflammatory drugs(NSAIDs),acetaminophen(ACT),aspirin(ASP)and ibuprofen(IBP),were investigated and compared in their alone and mixture conditions using Ti/SnO_(2)-Sb/La-PbO_(2).The pseudo-first-order degradation kinetics(k)order was k_(IBP-A)(0.110 min^(-1))>k_(ASP-A)(0.092 min^(-1))>k_(ACRT-A)(0.066 min^(-1))in their alone condition,while that was k_(ACT-M)(0.088 min^(-1))>k_(ASP-M)(0.063 min^(-1))>k_(IBP-M)(0.057 min^(-1)) in their mixture condition.The·OH apparent production rate constant of 5.23 mmol L^(-1)min^(-1)m^(-2) and an electrical energy per order(E_(EO)) value of 6.55 Wh/L could ensure the synchronous degradation of the NSAIDs mixture.The mineralization efficiency of NSAIDs mixture was 86.9%at 240 min with a mineralization current efficiency of 1.67%.Acetic acid and oxalic acid were the main products in the mineralization process for the both conditions.In the mixture condition,there were higher k values at lower initial concentrations and higher current density,while the presence of carbonate and humic acid inhibited their degradation.The results indicated electrochemical advanced oxidation process can effectively and synchronously mineralize NSAIDs mixture in wastewater.

Utilizing transparent and conductive SnO2 as electron mediator to enhance the photocatalytic performance of Z-scheme Si-SnO2-TiOx

Z-scheme photocatalysts,with strong redox ability,have a great potential for pollutants degradation.However,it is challenging to construct efficient Z-scheme photocatalysts because of their poor interfacial charge separation.Herein,by employing transparent and conductive SnO2 as electron mediator to pass light through and promote interfacial charge transportation,a novel Z-scheme photocatalyst Si-SnO2-TiOx(i<x<2)was constructed.The Z-scheme photocatalyst displayed an order of magnitude higher photocurrent density and a 4-fold increase in open-circuit potential compared to those of Si.Moreover,the onset potential shifted negatively for approximately 2.2 V.Benefiting from these advantages,this Z-scheme Si-SnO2-TiOx exhibited efficient photocatalytic performance toward phenol degradation and mineralization.15%of the phenol was degraded without bias potential and 70%of the TOC was removed during phenol degradation.Other typical pollutants such as bisphenol A and atrazine could also be degraded without bias potential.Introducing a transparent and conductive electron mediator to construct Z-scheme photocatalyst gives a new sight to the improvement of photocatalytic performance in Z scheme.

Electrochemical removal of nitrate in industrial wastewater

A number of recent studies have demonstrated that electrochemical technologies, including electroreduction （ER）, electrocoagulation （EC）, and electrodialysis （ED）, are effbctive in nitrate elimination in wastewater due to their high reactivity. To obtain the maximal elimination efficiency and current efficiency, many researchers have conducted experiments to investigate the optimal conditions （i.e., potential, cun＇ent density, pH value, plate distance, initial nitrate concentration, electrolyte, and other factors） tbr nitrate elimination. The mechanism of ER, EC and ED for nitrate removal has been fully elucidated. The ER mechanism of nitrate undergoes electron transfer and hydrogenation reduction. The EC pathways of nitrate removal include reduction, coagulation and flotation. The ED pathways of nitrate include redox reaction and dialysis. Although the electrochemical technology can remove nitrate from wastewater efficiently, many problems （such as relatively low selectivity toward nitrogen, sludge production and brine generation） still hinder electrochemical treatment implementa- tion. This paper critically presents an overview of the current state-of-the-art of electrochemical denitrification to enhance the removal efficiency and overcome the shortages, and will significantly improve the understanding of the detailed processes and mechanisms of nitrate removal by electrochemical treatment and provide useful information to scientific research and actual practice.

Ag-single atoms modified S_(1.66)-N_(1.91)/TiO_(2-x)for photocatalytic activation of peroxymonosulfate for bisphenol A degradation

In this study,Ag_(0.23)/(S_(1.66)-N_(1.91)/TiO_(2-x))single-atom photocatalyst was synthesized by in-situ photoreducing of silver on S,N-TiO_(2-x) nanocomposite and used to degrade bisphenol A(BPA)through heterogeneous activation of potassium peroxymonosulfate(PMS)under visible-light illumination.The structure,physicochemical property,morphology,and electronic property were evalutated by X-ray diffraction(XRD),Raman spectrum,X-ray photoelectron spectra(XPS),high-resolution transmission electron microscopy(HR-TEM),UV-vis diffuse reflectance spectra(UV-vis DRS),electron paramagnetic resonance(EPR)spectrum.Ag_(0.23)/(S_(1.66)-N_(1.91)/TiO_(2-x))single-atom photocatalyst exhibited 2.4 times higher activity for the synergetic degradation of BPA than that of its counterpart,and 48.73%mineralization rate of BPA also achieved.It was ascribed to the uniformly-dispersed metallic Ag atoms as the active site for accelerating the migration rate of photo-generated carrier for generation of high reactive radicals.The EPR experiments indicated that SO_(4)^(-) and ^(·)OH was jointly involved in BPA degradation.

Degradation of a persistent organic pollutant perfluorooctane sulphonate with Ti/SnO2eSb2O5/PbO2-PTFE anode

PbO2-poly tetra fluoro ethylene(PTFE)coating anode was prepared through electrodeposition method,which involved the use of scanning electron microscope,linear sweep voltammetry,contact angle,and accelerated life test.Degradation of perfluorooctane sulfonate(PFOS)with Ti/PbO2 and Ti/SnO2eSb2O5/PbO2-PTFE anodes was performed.Operating parameters,including initial concentration of PFOS,current density,and initial pH value were evaluated.Experimental results indicated that Ti/SnO2eSb2O5/PbO2-PTFE had longer lifespan(46.5 h)than Ti/PbO2 anode(3.5 h).The hydrophobic property of PbO2 was substantially improved after the addition of PTFE.Hydrophilic Ti/PbO2 with the contact angle of 45.4was transformed into hydrophobic Ti/SnO2eSb2O5/PbO2-PTFE with a contact angle of 130.9.The electrochemical performance was also enhanced after PTFE particles were added into PbO2 electrodeposition coating.The oxygen evolution potential was increased by 0.32 V,and removal ratios of PFOS had increased from 53.5%to 89%after addition of PTFE.When initial PFOS concentration varied from 100 mg/L to 300 mg/L,PFOS removal ratios increased with the initial concentration.High current density favored the high PFOS removal ratio and the defluorination ratio.Low pH profited the degradation of PFOS.However,alkaline atmosphere had detrimental effect to the PFOS desulfonation.Intermediate products of PFOS degradation were identified with liquid chromatography system coupled with a triple-stage quadruple mass spectrometer.Moreover,mechanisms of PFOS degradation were proposed.

Role of hydrogen bond capacity of solvents in reactions of amines with CO2:A computational study

Various computational methods were employed to investigate the zwitterion formation,a critical step for the reaction of monoethanolamine with CO2,in five solvents(water,monoethanolamine,propylamine,methanol and chloroform)to probe the effect of hydrogen bond capacity of solvents on the reaction of amine with CO2 occurring in the amine-based CO2 capture process.The results indicate that the zwitterion can be formed in all considered solvents except chloroform.For two pairs of solvents(methanol and monoethanolamine,propylamine and chloroform)with similar dielectric constant but different hydrogen bond capacity,the solvents with higher hydrogen bond capacity(monoethanolamine and propylamine)facilitate the zwitterion formation.More importantly,kinetics parameters such as activation free energy for the zwitterion formation are more relevant to the hydrogen bond capacity than to dielectric constant of the considered solvents,clarifying the hydrogen bond capacity could be more important than dielectric constant in determining the kinetics of monoethanolamine with CO2.