Arsenic pollution poses a serious threat to human health,and is one of the most concerning environmental problems worldwide.The adsorption,fixation,and dissolution behaviors of arsenic on the surface of iron-(hydr-)ox...Arsenic pollution poses a serious threat to human health,and is one of the most concerning environmental problems worldwide.The adsorption,fixation,and dissolution behaviors of arsenic on the surface of iron-(hydr-)oxides influence the environmental routes of arsenic cycle geochemistry.Both inner-sphere and outer-sphere adsorption configurations of arsenic on iron oxides have been proposed based on X-ray adsorption spectra.However,there is no systematic study on the in situ speciation analysis and adsorption kinetics of these species at such interfaces,because of the lack of an efficient monitoring strategy.The correlation of surface speciation and environmental stability is still unknown.Here,a shell-isolated SiO_(2)@Ag@Au-based surface-enhanced Raman spectroscopy(SERS)platform was developed for speciation analysis of the adsorbed arsenic species by eliminating the chemical interaction between arsenic and silver.Using ferrihydrite as a typical iron oxide,the intrinsic Raman spectra of the inner-sphere(~830 cm^(−1))and outer-sphere(~660 cm^(−1))complexes at the adsorption interface were identified.For the first time,the in situ kinetic monitoring of the formation and transformation of these species was realized.By correlating the speciation to the sequential extraction results,the environmental stability of arsenic on ferrihydrite was shown to be closely related to the adsorption configuration.It was shown that stability can be significantly promoted by transforming loosely bonded species(outer-sphere complexes)into inner-sphere structures.Our work demonstrated the applicability of SERS with shell-isolated plasmonic particles for arsenic geochemical cycle monitoring and mechanism studies.It also provided a convenient tool for developing effective strategies for arsenic pollutant control and abatement.展开更多
Eight new organo polyoxoinetalate charge transfer complexes (DH)\-6X\-2W\-\{18\}O\-\{62\}·(solv)\-n(D=Oxin(8 hydroxyquinoline), Py(Pyridine), Tol(toluene), A(aniline), DMA (N,N dimethyaniline), DEA(N,N diethylani...Eight new organo polyoxoinetalate charge transfer complexes (DH)\-6X\-2W\-\{18\}O\-\{62\}·(solv)\-n(D=Oxin(8 hydroxyquinoline), Py(Pyridine), Tol(toluene), A(aniline), DMA (N,N dimethyaniline), DEA(N,N diethylaniline), X=P, As; solv=DMF, H\-2O) was synthesized and characterized by using elemental analysis, IR, ESR. Polarographly, CV. Conductivity measurement, and X ray circle diffraction. The results showed that the crystal of (H\-2quinH)\-6P\-2W\-\{18\}O\-\{62\}·20H\-2O is Triclinic Crystal System, Space group \%P\{1-\}\%, with \%a=1.4659(5), b=2.045(8), c =2.1153(4) nm, α=90.01(3), β=87.95(2), γ=89.05(3)°, V =6.3393(35) nm\+3. This shows that under the irradiated title compound charge transfer between the organic donor and polyoxometalate anion has taken place.\;Polargraphy and cyclic Voltammetry show that the (H\-2quinH)\-6P\-2W\-\{18\}O\-\{62\}·20H\-2O undergoes three one electron reversible reduction steps in aqueous solution and four one electron quasi reversible reduction in DMF. Room temperature Conductivities of eight the title compounds ranging from 1.2×10\+\{-8\} to 3.6×10\+\{-9\} S·cm\+\{-1\} showed weak semiconducting behaviors.展开更多
基金the National Natural Science Foundation of China(Nos.22106147 and 22076052)Natural Science Foundation of Hubei Province(No.2021CFB131)+1 种基金China Postdoctoral Science Foundation(No.2021M703005)the Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)(No.G1323521102).
文摘Arsenic pollution poses a serious threat to human health,and is one of the most concerning environmental problems worldwide.The adsorption,fixation,and dissolution behaviors of arsenic on the surface of iron-(hydr-)oxides influence the environmental routes of arsenic cycle geochemistry.Both inner-sphere and outer-sphere adsorption configurations of arsenic on iron oxides have been proposed based on X-ray adsorption spectra.However,there is no systematic study on the in situ speciation analysis and adsorption kinetics of these species at such interfaces,because of the lack of an efficient monitoring strategy.The correlation of surface speciation and environmental stability is still unknown.Here,a shell-isolated SiO_(2)@Ag@Au-based surface-enhanced Raman spectroscopy(SERS)platform was developed for speciation analysis of the adsorbed arsenic species by eliminating the chemical interaction between arsenic and silver.Using ferrihydrite as a typical iron oxide,the intrinsic Raman spectra of the inner-sphere(~830 cm^(−1))and outer-sphere(~660 cm^(−1))complexes at the adsorption interface were identified.For the first time,the in situ kinetic monitoring of the formation and transformation of these species was realized.By correlating the speciation to the sequential extraction results,the environmental stability of arsenic on ferrihydrite was shown to be closely related to the adsorption configuration.It was shown that stability can be significantly promoted by transforming loosely bonded species(outer-sphere complexes)into inner-sphere structures.Our work demonstrated the applicability of SERS with shell-isolated plasmonic particles for arsenic geochemical cycle monitoring and mechanism studies.It also provided a convenient tool for developing effective strategies for arsenic pollutant control and abatement.
文摘H2 [(n-Bu)4N]3 [As (SiW11O39)], Mr = 3478. 89, cubic, space groupI43m, a=b=c= 17. 785 (8) A, V=5625. 0 A3, Z= 1, Dc= 2. 05 g/cm3, μ(MoKα)= 118. 3 cm-1, F(000) = 3808, final R= 0. 072 and Rw= 0. 083 for 248 observed re-flections with I≥3. 8σ(I). X-ray analysis shows that the heteropolyanion [As (SiW11-O39)]5- contains a central SiO4 unit encapsulated by a cage composed of arsenic, tung-sten and oxygen atoms.
文摘Eight new organo polyoxoinetalate charge transfer complexes (DH)\-6X\-2W\-\{18\}O\-\{62\}·(solv)\-n(D=Oxin(8 hydroxyquinoline), Py(Pyridine), Tol(toluene), A(aniline), DMA (N,N dimethyaniline), DEA(N,N diethylaniline), X=P, As; solv=DMF, H\-2O) was synthesized and characterized by using elemental analysis, IR, ESR. Polarographly, CV. Conductivity measurement, and X ray circle diffraction. The results showed that the crystal of (H\-2quinH)\-6P\-2W\-\{18\}O\-\{62\}·20H\-2O is Triclinic Crystal System, Space group \%P\{1-\}\%, with \%a=1.4659(5), b=2.045(8), c =2.1153(4) nm, α=90.01(3), β=87.95(2), γ=89.05(3)°, V =6.3393(35) nm\+3. This shows that under the irradiated title compound charge transfer between the organic donor and polyoxometalate anion has taken place.\;Polargraphy and cyclic Voltammetry show that the (H\-2quinH)\-6P\-2W\-\{18\}O\-\{62\}·20H\-2O undergoes three one electron reversible reduction steps in aqueous solution and four one electron quasi reversible reduction in DMF. Room temperature Conductivities of eight the title compounds ranging from 1.2×10\+\{-8\} to 3.6×10\+\{-9\} S·cm\+\{-1\} showed weak semiconducting behaviors.
