Lithium plays an increasingly important role in scientific and industrial processes, and it is extremely important to extract lithium from a high Mg^(2+)/Li^(+) mass ratio brine or to recover lithium from the leachate...Lithium plays an increasingly important role in scientific and industrial processes, and it is extremely important to extract lithium from a high Mg^(2+)/Li^(+) mass ratio brine or to recover lithium from the leachate of spent lithiumion batteries. Conventional wisdom shows that Li^(+) with low valence states has a much weaker adsorption(and absorption energy) with graphene than multivalent ions such as Mg^(2+). Here, we show the selective adsorption of Li^(+) in thermally reduced graphene oxide(rGO) membranes over other metal ions such as Mg^(2+), Co^(2+), Mn^(2+),Ni^(2+), or Fe^(2+). Interestingly, the adsorption strength of Li^(+) reaches up to 5 times the adsorption strength of Mg^(2+),and the mass ratio of a mixed Mg^(2+)/Li^(+) solution at a very high value of 500 : 1 can be effectively reduced to 0.7 : 1 within only six experimental treatment cycles, demonstrating the excellent applicability of the rGO membranes in the Mg^(2+)/Li^(+) separation. A theoretical analysis indicates that this unexpected selectivity is attributed to the competition between cation–π interaction and steric exclusion when hydrated cations enter the confined space of the rGO membranes.展开更多
Fe^(2+)is of considerable importance in plant growth and crop production.However,most Fe elements in nature favor existing in the trivalent state,which often causes the deficiency of Fe^(2+)in plants.Here,we report th...Fe^(2+)is of considerable importance in plant growth and crop production.However,most Fe elements in nature favor existing in the trivalent state,which often causes the deficiency of Fe^(2+)in plants.Here,we report the Fe valence state change from Fe^(3+)to Fe^(2+)by using leaves.This valence state change was confirmed by x-ray photoelectron spectroscopy in Fe-Cl@leaves.Fourier transform infrared and ultraviolet-visible spectroscopy demonstrated that aromatic ring groups were included in leaves,and cation-π𝜋interactions between Fe cations and the components containing aromatic rings in leaves were measured.Further,density functional theory calculations revealed that the most stable adsorption site for hydrated Fe^(3+)cation was the region where hydroxyl groups and aromatic rings coexist.Moreover,molecular orbital and charge decomposition analysis revealed that the aromatic rings took the major part(59%)of the whole net charge transfer between leaves and Fe cations.This work provides a high-efficiency and eco-friendly way to transform the Fe valence state from Fe^(3+)to Fe^(2+),and affords a new insight into the valance change between plant organisms with cations.展开更多
Recently,there are great efforts that have been taken to suppressing/controlling the coffee ring effect,but it is of challenge to achieve inexpensive and efficient control with less disturbance,suitable for scalable p...Recently,there are great efforts that have been taken to suppressing/controlling the coffee ring effect,but it is of challenge to achieve inexpensive and efficient control with less disturbance,suitable for scalable production and highly enhancing the printing/dyeing color fastness.By only adding trace amounts of salt into the suspensions,here we experimentally achieve the facile and highly efficient control of the coffee ring effect of suspended matter on substrates of graphene,natural graphite,and polyethylene terephthalate surfaces.Notably,friction force measurements show that ion-controlled uniform patterns also greatly enhance color fastness.Molecular dynamics simulations reveal that,due to strong hydrated cation-π interactions between hydrated cations and aromatic rings in the substrate surface,the suspended matters are adsorbed on the surfaces mediated by cations so that the suspended matters are uniformly distributed.These findings will open new avenues for fabricating functional patterns on graphene substrates and will benefit practical applications including printing,coating,and dyeing.展开更多
基金Supported by the Fundamental Research Funds for the Central Universitiesthe National Natural Science Foundation of China(Grant Nos. 11974366, 11675246, 12074341, U1832170, and U1832150)+2 种基金the Key Research Program of Chinese Academy of Sciences(Grant No. QYZDJ-SSW-SLH053)the Computer Network Information Center of the Chinese Academy of Sciencesthe Shanghai Supercomputer Center of China。
文摘Lithium plays an increasingly important role in scientific and industrial processes, and it is extremely important to extract lithium from a high Mg^(2+)/Li^(+) mass ratio brine or to recover lithium from the leachate of spent lithiumion batteries. Conventional wisdom shows that Li^(+) with low valence states has a much weaker adsorption(and absorption energy) with graphene than multivalent ions such as Mg^(2+). Here, we show the selective adsorption of Li^(+) in thermally reduced graphene oxide(rGO) membranes over other metal ions such as Mg^(2+), Co^(2+), Mn^(2+),Ni^(2+), or Fe^(2+). Interestingly, the adsorption strength of Li^(+) reaches up to 5 times the adsorption strength of Mg^(2+),and the mass ratio of a mixed Mg^(2+)/Li^(+) solution at a very high value of 500 : 1 can be effectively reduced to 0.7 : 1 within only six experimental treatment cycles, demonstrating the excellent applicability of the rGO membranes in the Mg^(2+)/Li^(+) separation. A theoretical analysis indicates that this unexpected selectivity is attributed to the competition between cation–π interaction and steric exclusion when hydrated cations enter the confined space of the rGO membranes.
基金supported by the National Natural Science Foundation of China(Grant Nos.11974366,12004110,and 12147169)the Fundamental Research Funds for the Center Universities.
文摘Fe^(2+)is of considerable importance in plant growth and crop production.However,most Fe elements in nature favor existing in the trivalent state,which often causes the deficiency of Fe^(2+)in plants.Here,we report the Fe valence state change from Fe^(3+)to Fe^(2+)by using leaves.This valence state change was confirmed by x-ray photoelectron spectroscopy in Fe-Cl@leaves.Fourier transform infrared and ultraviolet-visible spectroscopy demonstrated that aromatic ring groups were included in leaves,and cation-π𝜋interactions between Fe cations and the components containing aromatic rings in leaves were measured.Further,density functional theory calculations revealed that the most stable adsorption site for hydrated Fe^(3+)cation was the region where hydroxyl groups and aromatic rings coexist.Moreover,molecular orbital and charge decomposition analysis revealed that the aromatic rings took the major part(59%)of the whole net charge transfer between leaves and Fe cations.This work provides a high-efficiency and eco-friendly way to transform the Fe valence state from Fe^(3+)to Fe^(2+),and affords a new insight into the valance change between plant organisms with cations.
基金the National Natural Science Foundation of China under Grant Nos.U1632135,U1832170,11862003,11474299,11574339,U1932123,and 11722548the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(Nos.QYZDJ-SSW-SLH053 and QYZDJ-SSW-SLH019)the Key Research Program of the Chinese Academy of Sciences(No.KJZDEW-M03)。
文摘Recently,there are great efforts that have been taken to suppressing/controlling the coffee ring effect,but it is of challenge to achieve inexpensive and efficient control with less disturbance,suitable for scalable production and highly enhancing the printing/dyeing color fastness.By only adding trace amounts of salt into the suspensions,here we experimentally achieve the facile and highly efficient control of the coffee ring effect of suspended matter on substrates of graphene,natural graphite,and polyethylene terephthalate surfaces.Notably,friction force measurements show that ion-controlled uniform patterns also greatly enhance color fastness.Molecular dynamics simulations reveal that,due to strong hydrated cation-π interactions between hydrated cations and aromatic rings in the substrate surface,the suspended matters are adsorbed on the surfaces mediated by cations so that the suspended matters are uniformly distributed.These findings will open new avenues for fabricating functional patterns on graphene substrates and will benefit practical applications including printing,coating,and dyeing.
