Water oxidation is the bottleneck of artificial photosynthesis.Since the first ruthenium-based molecular water oxidation catalyst,the blue dimer,was reported by Meyer’ s group in 1982,catalysts based on transition me...Water oxidation is the bottleneck of artificial photosynthesis.Since the first ruthenium-based molecular water oxidation catalyst,the blue dimer,was reported by Meyer’ s group in 1982,catalysts based on transition metals have been widely employed to explore the mechanism of water oxidation.Because the oxidation of water requires harsh oxidative conditions,the stability of transition complexes under the relevant catalytic conditions has always been a challenge.In this work,we report the redox properties of a CuⅢ complex(TAML-CuⅢ] with a redox-active macrocyclic ligand(TAML) and its reactivity toward catalytic water oxidation.TAML-CuⅢ displayed a completely different electrochemical behavior from that of the TAML-CoⅢ complex previously reported by our group.TAML-CuⅢ can only be oxidized by one-electron oxidation of the ligand to form TAML·+-CuⅢand cannot achieve water activation through the ligand-centered proton-coupled electron transfer that takes place in the case of TAML-CoⅢ.The generated TAML·+-CuⅢ intermediate can undergo further oxidation and ligand hydrolysis with the assistance of borate anions,triggering the formation of a heterogeneous B/CuOx nanocatalyst Therefore,the choice of the buffer solution has a significant influence on the electrochemical behavior and stability of molecular water oxidation catalysts.展开更多
Ni_(2)CoS_(4)was prepared by the liquid‑phase method and applied to the benzyl alcohol electro‑oxidation reaction(BAOR),demonstrating excellent catalytic activity[with a current density of 271 mA·cm^(-2)at 1.40 V...Ni_(2)CoS_(4)was prepared by the liquid‑phase method and applied to the benzyl alcohol electro‑oxidation reaction(BAOR),demonstrating excellent catalytic activity[with a current density of 271 mA·cm^(-2)at 1.40 V(vs RHE)]and long‑term stability.The S‑anion effect can regulate the charge distribution on the catalyst surface,thereby enhancing the additional adsorption capacity of OH-at the Co sites.By combining material characterization and theoretical calculations,it can be observed that this process can increase the concentration of the OH^(*)intermediate,accelerate the activation process of the Ni site,and ultimately achieve an improvement in overall activity and stability.展开更多
Comprehensive Summary To better understand the impact of different anions on the structures and SCO properties of the CoII SCO complexes,six new complexes[Co(terpy-CH_(2)OH)_(2)]A_(2)·sol(terpy-CH_(2)OH=4′-(hydr...Comprehensive Summary To better understand the impact of different anions on the structures and SCO properties of the CoII SCO complexes,six new complexes[Co(terpy-CH_(2)OH)_(2)]A_(2)·sol(terpy-CH_(2)OH=4′-(hydroxymethyl)-2,2′;6′,2″-terpyridine,A=Br^(–)(1,sol=1.5H_(2)O),I^(–)(2),N_(3)^(–)(3,sol=2H_(2)O),H_(3)BCN^(–)(4),OTf^(–)(5),and TsO^(–)(6,sol=4H_(2)O·CH_(3)CN),have been synthesized and characterized.All six compounds consist of mononuclear[Co(terpy-CH_(2)OH)_(2)]^(2+)cations and charge-balancing anions that differ in size,shape,and hydrogen bonding capacity.Complexes 1,2,3,and 6 displayed incomplete gradual SCO transitions,whereas 4 and 5 exhibited abrupt hysteretic spin transitions with loops of 12 and 16 K(250.0—262.0 K for 4,and 370.0—386.0 K for 5,respectively),closely resembling our previously reported complexes with SCN^(–)and SeCN^(–)anions.The occurrence of the order-disorder transition of the CH2OH groups and their transition temperatures are determined by the size and hydrogen bonding capability of the anions.Remarkably,the transition temperatures of complexes with H_(3)BCN^(–),SCN^(–),OTf^(–),and SeCN^(–)anions exhibit an upward trend as the size and mass of the anions increase,as confirmed through detailed single crystal structure analyses conducted in both high-spin and low-spin states for all four complexes.展开更多
This paper reports the effect of several competing anions on arsenate adsorption with maghemite nanoparticles. Sulphate （as SO4）, nitrate （as NO3-N）, phosphate （as PO4-P） ions and silicate-（as SiO2） were-studi...This paper reports the effect of several competing anions on arsenate adsorption with maghemite nanoparticles. Sulphate （as SO4）, nitrate （as NO3-N）, phosphate （as PO4-P） ions and silicate-（as SiO2） were-studied in dual solution with arsenate. Moreover, the combined effect of ions and other water characteristics were examined with a natural groundwater sample which was spiked with a certain amount of arsenate. Arsenate batch adsorption experiments were carried out with two different kinds of maghemite-a commercially, available one and a homemade one using the sol-gel orocess. Sulohate （≤250 mg.L-1） and nitrate （≤ 12 mg.L-1） had a neglivible effect onthe arsenate （0.5 mg.L-1） adsorption at pH 3. However, both phosphate （42.9 mg·L-1） and silicate （450 mg.L-j） had an adverse impact on arsenate （43 mg.L-1） adsorption at pH 7. Phosphate （41.5 mg.L-1） showed minimal competition with arsenate （0.5 mg.L-1）, while silicate （410 mg.L-1） inhibition was insignificant for all studied As（V） concentrations at p.H 3. The removal of arsenate from the groundwater sample was as efficient as from labo-ratory water tor 0.3 mgL -1 AS（V） botll at pH3 and pH7.展开更多
The effect of the anion in the original rare earth element（REE） solution on the reversible ion exchange of Ce nitrate and Ce sulfate with the Dowex 50 W X8 was investigated using attenuated total reflection infrared...The effect of the anion in the original rare earth element（REE） solution on the reversible ion exchange of Ce nitrate and Ce sulfate with the Dowex 50 W X8 was investigated using attenuated total reflection infrared（ATR-IR） spectroscopy, continuous flow reactor studies coupled with inductively coupled plasma mass spectroscopy（ICP-MS）, and density functional theory（DFT）. The simulated IR spectrum at the DFT B3 LYP/6-31 G（d） level was compared to the experimental results to characterize the IR spectrum, molecular interactions, and bonding of the ion exchanged species. The continuous liquid flow reactor studies show a capacity of 0.72 mmol/g sorbent for the Ce nitrateand 0.96 mmol/g sorbent for the Ce sulfate with the Dowex 50 W X8. The flow reactor studies reveal the type of solute anion（SO_4^（（2-）） or NO_3^（（-））） associated with the REE during cation exchange significantly affects the sorption capacity of the Dowex 50 W X8 ion exchange resin. The calculated REE binding energy（BE） and the DFT optimized structures suggest that the differences in sorption capacity is the result of the formation of different types of partially ionexchanged Ce_2^（（3＋））2 SO_4^（（2-）） and Ce^（（3＋）） 3 NO_3^（（-））. These results suggest that the solute anion affects the equilibrium constants of the Dowex resin by the formation of a charged layer capable of retaining the counterion. Modifying the sulfonic acid site（H＋） in the Dowex 50 W X8 with the NH_4~＋ counterion does not affect the sorption capacity and retention times of the Ce nitrate and Ce sulfate species. These results suggest that the counterions and co-ions having a finite size, may limit access to the Dowex sulfonate active site where the type of REE cation as a nitrate or sulfate in solution may significantly modify the sorption capacity of the ion exchange resin. Similar results are obtained during sorption with nitrates and sulfates of Sm and Yb.展开更多
The inhibition effect of rare earths on the production of ·O - 2 produced by radiolysis of aqueous sodium formate saturated with O 2 with high energy pulse electron beam was studied. The result indicates ...The inhibition effect of rare earths on the production of ·O - 2 produced by radiolysis of aqueous sodium formate saturated with O 2 with high energy pulse electron beam was studied. The result indicates that rare earth nitrate obviously inhibits the production of ·O - 2 . The inhibition rate is between 28 6% and 92%. The inhibition effect increases with the increase of rare earth nitrates concentration. The distinguish dose effect relationship was observed.展开更多
Cis-trans isomerization of [9]-annulenanion（1） and its 2-fluoro-,2-chloro-and 2-bromo-derivatives（2,3 and 4,respectively） were investigated at the HF/6-31G＊ and B3LYP/6-311＋＋G＊＊ levels of theory.Cis,cis,cis,c...Cis-trans isomerization of [9]-annulenanion（1） and its 2-fluoro-,2-chloro-and 2-bromo-derivatives（2,3 and 4,respectively） were investigated at the HF/6-31G＊ and B3LYP/6-311＋＋G＊＊ levels of theory.Cis,cis,cis,cis structures appear more stable than their corresponding cis,cis,cis,trans-isomers.The relative height of energy barriers for cis-trans isomerization is：2cis 〉1cis 〉3cis〉 4cis.This trend for the reverse trans-cis isomerization follows the electronegativity of the substituent at C-2（2trans 3trans 4trans 1trans）.展开更多
We present findings on the effect of nanometer-sized silica-based pores on the glass transition of aqueous solutions of lithium bis(trifluoromethane)sulfonimide(LiTFSI)and lithium difluorosulfimide(LiFSI),respectively...We present findings on the effect of nanometer-sized silica-based pores on the glass transition of aqueous solutions of lithium bis(trifluoromethane)sulfonimide(LiTFSI)and lithium difluorosulfimide(LiFSI),respectively.Our experimental results demonstrate a clear dependence of the confinement effect on the anion type,particularly for water-rich solutions,in which the precipitation of crystalized ice under cooling process induces the formation of freeze-concentrated phase confined between pore wall and core ice.As this liquid layer becomes thinner,the freeze-concentrated phase experiences glass transition at increasingly higher temperatures in solutions of LiTFSI.However,differently,for solutions of LiFSI and LiCl,this secondary confinement has a negligible effect on the glass transition of solutions confined wherein.These different behaviors emphasize the obvious difference in the dynamic properties’response of LiTFSI and LiFSI solutions to spatial confinement and particularly to the presence of the hydrophilic pore wall.展开更多
The optical effects of anion adsorption on silver sol have been studied, It was found that the anion adsorption can make the absorption peak of pure silver sol shifting to longer vevelenngth, which is attributed to th...The optical effects of anion adsorption on silver sol have been studied, It was found that the anion adsorption can make the absorption peak of pure silver sol shifting to longer vevelenngth, which is attributed to the reduction of the free electron density in the surface layer of the silver particle.展开更多
Rita rita exposed to a concentration of 6.9 mg per liter(96-h LC_(50)of an anionic detergent, dodecylbenzene sodium sulfonate)exhibited a gradual decrease in the lipid moieties of the epi- thelial cells,club cells,and...Rita rita exposed to a concentration of 6.9 mg per liter(96-h LC_(50)of an anionic detergent, dodecylbenzene sodium sulfonate)exhibited a gradual decrease in the lipid moieties of the epi- thelial cells,club cells,and goblet mucous cells lining the gill arch and gill filament epithelium. However,in time,no reaction of any of the lipid moieties could be observed,indicating the absence of the same,using various histochemical techniques.The results are discussed in light of the mechanistic understanding of detergent action.1989 Academic Press,Inc.展开更多
The effects of three electrolyte anions, ionic strength and pH on the adsorption of sulfate by two variablecharge soils, with different surface charge properties were studied. Under the conditions of the same pHand io...The effects of three electrolyte anions, ionic strength and pH on the adsorption of sulfate by two variablecharge soils, with different surface charge properties were studied. Under the conditions of the same pHand ionic strength the effect of electrolyte anions on the adsorption of sulfate was in the order of , indicating the difference of the nature among these three anions. For Ferralsol in the sameconcentration of chloride and perchloride solutions, the two sulfate adsorption-pH curves could intersectat certain pH value. When pH was higher than the intersecting point, more sulfate was adsorbed in theperchloride solution, while when it was lower than the intersecting point, more sulfate was adsorbed in thechloride solution. In different concentrations of electrolyte solution, the curves of the amount of oxy-acidanion adsorbed, which changed with pH, could intersect at a certain pH, which is termed point of zero salteffect （PZSE） on adsorption. The nature of electrolyte anions influenced obviously the appearance of PZSEfor sulfate adsorption. For ferraisol the curves of adsorption converged to about pH 7 in NaCl solution seemedto intersect in NaNO<sub>3</sub> solution and to have a typical PZSE for sulfate adsorption in NaClO<sub>4</sub> solution. ForAcrisol the three curves of adsorption were nearly parallel in NaCl and NaNO<sub>3</sub> solutions and converged topH 6.5 in NaClO<sub>4</sub> solution.展开更多
Aqueous batteries with metal anodes exhibit robust anodic capacities,but their energy densities are low because of the limited potential stabilities of aqueous electrolyte solutions.Current metal options,such as Zn an...Aqueous batteries with metal anodes exhibit robust anodic capacities,but their energy densities are low because of the limited potential stabilities of aqueous electrolyte solutions.Current metal options,such as Zn and Al,pose a dilemma:Zn lacks a sufficiently low redox potential,whereas Al tends to be strongly oxidized in aqueous environments.Our investigation introduces a novel rechargeable aqueous battery system based on Mn as the anode.We examine the effects of anions,electrolyte concentration,and diverse cathode chemistries.Notably,the ClO_(4)-based electrolyte solution exhibits improved deposition and dissolution efficiencies.Although stainless steel(SS 316 L)and Ni are stable current collectors for cathodes,they display limitations as anodes.However,using Ti as the anode resulted in increased Mn deposition and dissolution efficiencies.Moreover,we evaluate this system using various cathode materials,including Mn-intercalation-based inorganic(Ag0.33V2O5)and organic(perylenetetracarboxylic dianhydride)cathodes and an anionintercalation-chemistry(coronene)-based cathode.These configurations yield markedly higher output potentials compared to those of Zn metal batteries,highlighting the potential for an augmented energy density when using an Mn anode.This study outlines a systematic approach for use in optimizing metal anodes in Mn metal batteries,unlocking novel prospects for Mn-based batteries with diverse cathode chemistries.展开更多
Batch experiments were conducted to evaluate fluoride removal by Al,Fe,and Ti-based coagulants and adsorbents,as well as the effects of coexisting ions and formation of aluminum–fluoride complexes on fluoride removal...Batch experiments were conducted to evaluate fluoride removal by Al,Fe,and Ti-based coagulants and adsorbents,as well as the effects of coexisting ions and formation of aluminum–fluoride complexes on fluoride removal by co-precipitation with alum（Al_2（SO_4）_3·18H_2O）.Aluminum sulfate was more efficient than the other coagulants for fluoride removal in the pH range between 6 and 8.Nano-crystalline TiO_2 was more effective for fluoride removal than Al and Fe hydroxides in a pH range of 3–5.Coexisting anions in water decreased the removal of fluoride in the order：phosphate（2.5 mg/L） 〉 arsenate（0.1 mg/L） 〉 bicarbonate（200 mg/L） 〉sulfate（100 mg/L） = nitrate（100 mg/L） 〉 silicate（10 mg/L） at a pH of 6.0.The effect of silicate became more significant at pH 〉 7.0.Calcium and magnesium improved the removal of fluoride.Zeta-potential measurements determined that the adsorption of fluoride shifted the PZC of Al（OH）_3 precipitates from 8.9 to 8.4,indicating the chemical adsorption of fluoride at the surface.The presence of fluoride in solution significantly increased the soluble aluminum concentration at pH 〈 6.5.A Visual MINTEQ modeling study indicated that the increased aluminum solubility was caused by the formation of AlF^（2＋）,AlF^（＋2）,and AlF_3complexes.The AlF_x complexes decreased the removal of fluoride during co-precipitation with aluminum sulfate.展开更多
The kinetics of formic acid oxidation (FAO) on Pd(111) in 0.1 mol/L H2SO4+0.1 mol/L HCOOH with and without addition of Na2SO4 is studied using cyclic voltammetry and potential step method, which is compared with that ...The kinetics of formic acid oxidation (FAO) on Pd(111) in 0.1 mol/L H2SO4+0.1 mol/L HCOOH with and without addition of Na2SO4 is studied using cyclic voltammetry and potential step method, which is compared with that in 0.1 mol/L HClO4. It is found that adsorbed sulfate has significant inhibition effect on FAO kinetics. After addition of 0.05 mol/L or 0.1 mol/L Na2SO4, FAO current in the negative-going scan is found to be significantly smaller than that at the same potential in the positive-going scan. We speculate that at potentials positive of the phase transition potential for the (SO4*ad)m+[(H2O)n-H3O+] or(SO4*ad)m+[Na+(H2O)n-H3O+] adlayer, the adlayer structure probably becomes denser and more stable with the increase of potential or with the addition of Na2SO4. The formation of connected adlayer network greatly enhance the stability of the adlayer, and the insertion of positive-charged H+ or Na+ into the adlayer network further reduces the electrostatic repulsion between partially charged sulfates. As a result, the destruction/desorption of compact sulfate adlayer becomes more difficult, which leaves much less free sites on the surface for FAO, and thus FAO kinetics at higher potentials and in the subsequent negative-going potential scan is significantly inhibited.展开更多
Topomerization of [9] annulen anion （1） and its 2-fluoro-, 2-chloro- and 2- bromo-defivatives （2, 3 and 4, respectively） are studied at the HF/6-31G＊ and B3LYP/6-31 1＋＋G＊＊ levels of theory. The relative ease ...Topomerization of [9] annulen anion （1） and its 2-fluoro-, 2-chloro- and 2- bromo-defivatives （2, 3 and 4, respectively） are studied at the HF/6-31G＊ and B3LYP/6-31 1＋＋G＊＊ levels of theory. The relative ease of topomerization is dependent on the charge distribution and planarity of the ground state and the transition state of 9-membered rings as well as the size and electronegativity of halogen substituent. Consequently, the endo-2-halo-[9] annulen anion topomers become unstable and easily convert to related exo-topomers. Hence, according to the DFT calcu- lations, the order of topomerization energy barrier for endo = exo topomerization is lendo 〉 2endo 〉 3endo.展开更多
The [CdCl_4]^（2-） anion as a structure inducer has proved to be useful in the construction of cucurbit[n]urilmetal coordination architectures and materials. In order to better understand the role and influence of th...The [CdCl_4]^（2-） anion as a structure inducer has proved to be useful in the construction of cucurbit[n]urilmetal coordination architectures and materials. In order to better understand the role and influence of the structure inducer in Q[n] systems, we report herein the self-assembly of Q[6] solely in the presence of[CdCl_4]^（2-）anions and in the presence of both a linear cationic organic vip and [CdCl_4]^（2-）anions. X-ray diffraction analysis revealed that 1D Q[6] porous channels were formed by the noncovalent interactions between Q[6] and [CdCl_4]^（2-）anions, but the ＇＇honeycomb effect＇＇ was not observed in the present study.However, it seems that the ＇＇honeycomb effect＇＇ and the self-assembly of Q[6] with [CdCl_4]^（2-）anions can be significantly modified and switched in the presence of a linear cationic dibutylamine vip through some unusual noncovalent interactions.展开更多
文摘Water oxidation is the bottleneck of artificial photosynthesis.Since the first ruthenium-based molecular water oxidation catalyst,the blue dimer,was reported by Meyer’ s group in 1982,catalysts based on transition metals have been widely employed to explore the mechanism of water oxidation.Because the oxidation of water requires harsh oxidative conditions,the stability of transition complexes under the relevant catalytic conditions has always been a challenge.In this work,we report the redox properties of a CuⅢ complex(TAML-CuⅢ] with a redox-active macrocyclic ligand(TAML) and its reactivity toward catalytic water oxidation.TAML-CuⅢ displayed a completely different electrochemical behavior from that of the TAML-CoⅢ complex previously reported by our group.TAML-CuⅢ can only be oxidized by one-electron oxidation of the ligand to form TAML·+-CuⅢand cannot achieve water activation through the ligand-centered proton-coupled electron transfer that takes place in the case of TAML-CoⅢ.The generated TAML·+-CuⅢ intermediate can undergo further oxidation and ligand hydrolysis with the assistance of borate anions,triggering the formation of a heterogeneous B/CuOx nanocatalyst Therefore,the choice of the buffer solution has a significant influence on the electrochemical behavior and stability of molecular water oxidation catalysts.
文摘Ni_(2)CoS_(4)was prepared by the liquid‑phase method and applied to the benzyl alcohol electro‑oxidation reaction(BAOR),demonstrating excellent catalytic activity[with a current density of 271 mA·cm^(-2)at 1.40 V(vs RHE)]and long‑term stability.The S‑anion effect can regulate the charge distribution on the catalyst surface,thereby enhancing the additional adsorption capacity of OH-at the Co sites.By combining material characterization and theoretical calculations,it can be observed that this process can increase the concentration of the OH^(*)intermediate,accelerate the activation process of the Ni site,and ultimately achieve an improvement in overall activity and stability.
基金supported by the National Natural Science Foundation of China(22273036,21973039)Y.-C S.acknowledges the support from the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX23_0108).
文摘Comprehensive Summary To better understand the impact of different anions on the structures and SCO properties of the CoII SCO complexes,six new complexes[Co(terpy-CH_(2)OH)_(2)]A_(2)·sol(terpy-CH_(2)OH=4′-(hydroxymethyl)-2,2′;6′,2″-terpyridine,A=Br^(–)(1,sol=1.5H_(2)O),I^(–)(2),N_(3)^(–)(3,sol=2H_(2)O),H_(3)BCN^(–)(4),OTf^(–)(5),and TsO^(–)(6,sol=4H_(2)O·CH_(3)CN),have been synthesized and characterized.All six compounds consist of mononuclear[Co(terpy-CH_(2)OH)_(2)]^(2+)cations and charge-balancing anions that differ in size,shape,and hydrogen bonding capacity.Complexes 1,2,3,and 6 displayed incomplete gradual SCO transitions,whereas 4 and 5 exhibited abrupt hysteretic spin transitions with loops of 12 and 16 K(250.0—262.0 K for 4,and 370.0—386.0 K for 5,respectively),closely resembling our previously reported complexes with SCN^(–)and SeCN^(–)anions.The occurrence of the order-disorder transition of the CH2OH groups and their transition temperatures are determined by the size and hydrogen bonding capability of the anions.Remarkably,the transition temperatures of complexes with H_(3)BCN^(–),SCN^(–),OTf^(–),and SeCN^(–)anions exhibit an upward trend as the size and mass of the anions increase,as confirmed through detailed single crystal structure analyses conducted in both high-spin and low-spin states for all four complexes.
文摘This paper reports the effect of several competing anions on arsenate adsorption with maghemite nanoparticles. Sulphate （as SO4）, nitrate （as NO3-N）, phosphate （as PO4-P） ions and silicate-（as SiO2） were-studied in dual solution with arsenate. Moreover, the combined effect of ions and other water characteristics were examined with a natural groundwater sample which was spiked with a certain amount of arsenate. Arsenate batch adsorption experiments were carried out with two different kinds of maghemite-a commercially, available one and a homemade one using the sol-gel orocess. Sulohate （≤250 mg.L-1） and nitrate （≤ 12 mg.L-1） had a neglivible effect onthe arsenate （0.5 mg.L-1） adsorption at pH 3. However, both phosphate （42.9 mg·L-1） and silicate （450 mg.L-j） had an adverse impact on arsenate （43 mg.L-1） adsorption at pH 7. Phosphate （41.5 mg.L-1） showed minimal competition with arsenate （0.5 mg.L-1）, while silicate （410 mg.L-1） inhibition was insignificant for all studied As（V） concentrations at p.H 3. The removal of arsenate from the groundwater sample was as efficient as from labo-ratory water tor 0.3 mgL -1 AS（V） botll at pH3 and pH7.
基金Project supported by NETL's ongoing research under the Research&Engineering Services(RES)contract DE-FE0004000
文摘The effect of the anion in the original rare earth element（REE） solution on the reversible ion exchange of Ce nitrate and Ce sulfate with the Dowex 50 W X8 was investigated using attenuated total reflection infrared（ATR-IR） spectroscopy, continuous flow reactor studies coupled with inductively coupled plasma mass spectroscopy（ICP-MS）, and density functional theory（DFT）. The simulated IR spectrum at the DFT B3 LYP/6-31 G（d） level was compared to the experimental results to characterize the IR spectrum, molecular interactions, and bonding of the ion exchanged species. The continuous liquid flow reactor studies show a capacity of 0.72 mmol/g sorbent for the Ce nitrateand 0.96 mmol/g sorbent for the Ce sulfate with the Dowex 50 W X8. The flow reactor studies reveal the type of solute anion（SO_4^（（2-）） or NO_3^（（-））） associated with the REE during cation exchange significantly affects the sorption capacity of the Dowex 50 W X8 ion exchange resin. The calculated REE binding energy（BE） and the DFT optimized structures suggest that the differences in sorption capacity is the result of the formation of different types of partially ionexchanged Ce_2^（（3＋））2 SO_4^（（2-）） and Ce^（（3＋）） 3 NO_3^（（-））. These results suggest that the solute anion affects the equilibrium constants of the Dowex resin by the formation of a charged layer capable of retaining the counterion. Modifying the sulfonic acid site（H＋） in the Dowex 50 W X8 with the NH_4~＋ counterion does not affect the sorption capacity and retention times of the Ce nitrate and Ce sulfate species. These results suggest that the counterions and co-ions having a finite size, may limit access to the Dowex sulfonate active site where the type of REE cation as a nitrate or sulfate in solution may significantly modify the sorption capacity of the ion exchange resin. Similar results are obtained during sorption with nitrates and sulfates of Sm and Yb.
文摘The inhibition effect of rare earths on the production of ·O - 2 produced by radiolysis of aqueous sodium formate saturated with O 2 with high energy pulse electron beam was studied. The result indicates that rare earth nitrate obviously inhibits the production of ·O - 2 . The inhibition rate is between 28 6% and 92%. The inhibition effect increases with the increase of rare earth nitrates concentration. The distinguish dose effect relationship was observed.
文摘Cis-trans isomerization of [9]-annulenanion（1） and its 2-fluoro-,2-chloro-and 2-bromo-derivatives（2,3 and 4,respectively） were investigated at the HF/6-31G＊ and B3LYP/6-311＋＋G＊＊ levels of theory.Cis,cis,cis,cis structures appear more stable than their corresponding cis,cis,cis,trans-isomers.The relative height of energy barriers for cis-trans isomerization is：2cis 〉1cis 〉3cis〉 4cis.This trend for the reverse trans-cis isomerization follows the electronegativity of the substituent at C-2（2trans 3trans 4trans 1trans）.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11974385 and 91956101).
文摘We present findings on the effect of nanometer-sized silica-based pores on the glass transition of aqueous solutions of lithium bis(trifluoromethane)sulfonimide(LiTFSI)and lithium difluorosulfimide(LiFSI),respectively.Our experimental results demonstrate a clear dependence of the confinement effect on the anion type,particularly for water-rich solutions,in which the precipitation of crystalized ice under cooling process induces the formation of freeze-concentrated phase confined between pore wall and core ice.As this liquid layer becomes thinner,the freeze-concentrated phase experiences glass transition at increasingly higher temperatures in solutions of LiTFSI.However,differently,for solutions of LiFSI and LiCl,this secondary confinement has a negligible effect on the glass transition of solutions confined wherein.These different behaviors emphasize the obvious difference in the dynamic properties’response of LiTFSI and LiFSI solutions to spatial confinement and particularly to the presence of the hydrophilic pore wall.
文摘The optical effects of anion adsorption on silver sol have been studied, It was found that the anion adsorption can make the absorption peak of pure silver sol shifting to longer vevelenngth, which is attributed to the reduction of the free electron density in the surface layer of the silver particle.
文摘Rita rita exposed to a concentration of 6.9 mg per liter(96-h LC_(50)of an anionic detergent, dodecylbenzene sodium sulfonate)exhibited a gradual decrease in the lipid moieties of the epi- thelial cells,club cells,and goblet mucous cells lining the gill arch and gill filament epithelium. However,in time,no reaction of any of the lipid moieties could be observed,indicating the absence of the same,using various histochemical techniques.The results are discussed in light of the mechanistic understanding of detergent action.1989 Academic Press,Inc.
文摘The effects of three electrolyte anions, ionic strength and pH on the adsorption of sulfate by two variablecharge soils, with different surface charge properties were studied. Under the conditions of the same pHand ionic strength the effect of electrolyte anions on the adsorption of sulfate was in the order of , indicating the difference of the nature among these three anions. For Ferralsol in the sameconcentration of chloride and perchloride solutions, the two sulfate adsorption-pH curves could intersectat certain pH value. When pH was higher than the intersecting point, more sulfate was adsorbed in theperchloride solution, while when it was lower than the intersecting point, more sulfate was adsorbed in thechloride solution. In different concentrations of electrolyte solution, the curves of the amount of oxy-acidanion adsorbed, which changed with pH, could intersect at a certain pH, which is termed point of zero salteffect （PZSE） on adsorption. The nature of electrolyte anions influenced obviously the appearance of PZSEfor sulfate adsorption. For ferraisol the curves of adsorption converged to about pH 7 in NaCl solution seemedto intersect in NaNO<sub>3</sub> solution and to have a typical PZSE for sulfate adsorption in NaClO<sub>4</sub> solution. ForAcrisol the three curves of adsorption were nearly parallel in NaCl and NaNO<sub>3</sub> solutions and converged topH 6.5 in NaClO<sub>4</sub> solution.
基金supported by the Global Joint Research Program funded by the Pukyong National University(202411790001)。
文摘Aqueous batteries with metal anodes exhibit robust anodic capacities,but their energy densities are low because of the limited potential stabilities of aqueous electrolyte solutions.Current metal options,such as Zn and Al,pose a dilemma:Zn lacks a sufficiently low redox potential,whereas Al tends to be strongly oxidized in aqueous environments.Our investigation introduces a novel rechargeable aqueous battery system based on Mn as the anode.We examine the effects of anions,electrolyte concentration,and diverse cathode chemistries.Notably,the ClO_(4)-based electrolyte solution exhibits improved deposition and dissolution efficiencies.Although stainless steel(SS 316 L)and Ni are stable current collectors for cathodes,they display limitations as anodes.However,using Ti as the anode resulted in increased Mn deposition and dissolution efficiencies.Moreover,we evaluate this system using various cathode materials,including Mn-intercalation-based inorganic(Ag0.33V2O5)and organic(perylenetetracarboxylic dianhydride)cathodes and an anionintercalation-chemistry(coronene)-based cathode.These configurations yield markedly higher output potentials compared to those of Zn metal batteries,highlighting the potential for an augmented energy density when using an Mn anode.This study outlines a systematic approach for use in optimizing metal anodes in Mn metal batteries,unlocking novel prospects for Mn-based batteries with diverse cathode chemistries.
文摘Batch experiments were conducted to evaluate fluoride removal by Al,Fe,and Ti-based coagulants and adsorbents,as well as the effects of coexisting ions and formation of aluminum–fluoride complexes on fluoride removal by co-precipitation with alum（Al_2（SO_4）_3·18H_2O）.Aluminum sulfate was more efficient than the other coagulants for fluoride removal in the pH range between 6 and 8.Nano-crystalline TiO_2 was more effective for fluoride removal than Al and Fe hydroxides in a pH range of 3–5.Coexisting anions in water decreased the removal of fluoride in the order：phosphate（2.5 mg/L） 〉 arsenate（0.1 mg/L） 〉 bicarbonate（200 mg/L） 〉sulfate（100 mg/L） = nitrate（100 mg/L） 〉 silicate（10 mg/L） at a pH of 6.0.The effect of silicate became more significant at pH 〉 7.0.Calcium and magnesium improved the removal of fluoride.Zeta-potential measurements determined that the adsorption of fluoride shifted the PZC of Al（OH）_3 precipitates from 8.9 to 8.4,indicating the chemical adsorption of fluoride at the surface.The presence of fluoride in solution significantly increased the soluble aluminum concentration at pH 〈 6.5.A Visual MINTEQ modeling study indicated that the increased aluminum solubility was caused by the formation of AlF^（2＋）,AlF^（＋2）,and AlF_3complexes.The AlF_x complexes decreased the removal of fluoride during co-precipitation with aluminum sulfate.
基金supported by the National Natural Science Foundation of China(No.21872132 and No.21832004)973 Program from the Ministry of Science and Technology of China(No.201503932301)
文摘The kinetics of formic acid oxidation (FAO) on Pd(111) in 0.1 mol/L H2SO4+0.1 mol/L HCOOH with and without addition of Na2SO4 is studied using cyclic voltammetry and potential step method, which is compared with that in 0.1 mol/L HClO4. It is found that adsorbed sulfate has significant inhibition effect on FAO kinetics. After addition of 0.05 mol/L or 0.1 mol/L Na2SO4, FAO current in the negative-going scan is found to be significantly smaller than that at the same potential in the positive-going scan. We speculate that at potentials positive of the phase transition potential for the (SO4*ad)m+[(H2O)n-H3O+] or(SO4*ad)m+[Na+(H2O)n-H3O+] adlayer, the adlayer structure probably becomes denser and more stable with the increase of potential or with the addition of Na2SO4. The formation of connected adlayer network greatly enhance the stability of the adlayer, and the insertion of positive-charged H+ or Na+ into the adlayer network further reduces the electrostatic repulsion between partially charged sulfates. As a result, the destruction/desorption of compact sulfate adlayer becomes more difficult, which leaves much less free sites on the surface for FAO, and thus FAO kinetics at higher potentials and in the subsequent negative-going potential scan is significantly inhibited.
文摘Topomerization of [9] annulen anion （1） and its 2-fluoro-, 2-chloro- and 2- bromo-defivatives （2, 3 and 4, respectively） are studied at the HF/6-31G＊ and B3LYP/6-31 1＋＋G＊＊ levels of theory. The relative ease of topomerization is dependent on the charge distribution and planarity of the ground state and the transition state of 9-membered rings as well as the size and electronegativity of halogen substituent. Consequently, the endo-2-halo-[9] annulen anion topomers become unstable and easily convert to related exo-topomers. Hence, according to the DFT calcu- lations, the order of topomerization energy barrier for endo = exo topomerization is lendo 〉 2endo 〉 3endo.
基金supported by the National Natural Science Foundation of China (No. 21361006)‘‘Chun-Hui’’ Fund of Chinese Ministry of Education (No. Z2011037)Guizhou University (No. 20127027)
文摘The [CdCl_4]^（2-） anion as a structure inducer has proved to be useful in the construction of cucurbit[n]urilmetal coordination architectures and materials. In order to better understand the role and influence of the structure inducer in Q[n] systems, we report herein the self-assembly of Q[6] solely in the presence of[CdCl_4]^（2-）anions and in the presence of both a linear cationic organic vip and [CdCl_4]^（2-）anions. X-ray diffraction analysis revealed that 1D Q[6] porous channels were formed by the noncovalent interactions between Q[6] and [CdCl_4]^（2-）anions, but the ＇＇honeycomb effect＇＇ was not observed in the present study.However, it seems that the ＇＇honeycomb effect＇＇ and the self-assembly of Q[6] with [CdCl_4]^（2-）anions can be significantly modified and switched in the presence of a linear cationic dibutylamine vip through some unusual noncovalent interactions.
