The difficulties of washing during the dressing of kaolin ore have been analyzed, the multistep intermittent washing model has been deduced, and effective methods for dealing with the difficulties were put forward. Ex...The difficulties of washing during the dressing of kaolin ore have been analyzed, the multistep intermittent washing model has been deduced, and effective methods for dealing with the difficulties were put forward. Experimental results show that the bleaching and washing process was enhanced, the washing time was shortened and the consumption of water was reduced by means of adding flocculant.展开更多
Spontaneously polarized crystals with intrinsic electric dipole moment have attracted immense interest as excellent functional materials for extensive applications.It is of great significance to engineer sustainable s...Spontaneously polarized crystals with intrinsic electric dipole moment have attracted immense interest as excellent functional materials for extensive applications.It is of great significance to engineer sustainable spontaneously polarized materials with fascinating characteristics and performance for activating air and water.Herein,a novel strategy based on the synergy of mechanical activation(MA)and biomimetic mineralization(BM)was created to construct spontaneously polarized ceramic.MA induced the structural damage of clay and promoted the dissolution of ions and the release of free proteins,contributing to the formation of silicate precursor in BM process.After high temperature firing,the silicate precursor in clay was converted to form KCa_(3)AlCa_(3)Si_(4)O_(16)(hexagonal crystal system,L^(6)symmetry type,and P63 space group)in the resulting spontaneously polarized ceramic.The non-centrosymmetric structure of KCa_(3)AlCa_(3)Si4O_(16)and the high intrinsic electric dipole moments contributed by K(1)polyhedrons resulted in high spontaneous polarization(0.2322μC/cm^(2))and far-infrared emissivity(0.951)of spontaneously polarized ceramic.In air,spontaneously polarized ceramic can activate H_(2)O and O_(2)molecules to form negative air ions owing to surface electric field.In water,spontaneously polarized ceramic can disaggregate large water clusters to form small water clusters ascribed to surface electric field and far-infrared emission;water pH can be regulated from weak acidity to approximate neutrality via the capture of electrons by H+ions to produce releasable hydrogen gas.This work provides great promise for rational design and synthesis of spontaneously polarized materials for functional applications.展开更多
Water-assisted proton hopping(WAPH)plays an important role in the aqueous-phase hydrogenation of levulinic acid(LA)toγ-valerolactone(GVL).In this study,based on a strategy of spontaneously polarized ceramic(SPCE)-rei...Water-assisted proton hopping(WAPH)plays an important role in the aqueous-phase hydrogenation of levulinic acid(LA)toγ-valerolactone(GVL).In this study,based on a strategy of spontaneously polarized ceramic(SPCE)-reinforced WAPH,a Ni-Co/SPCE-C catalyst was constructed by high-temperature calci-nation of a dual mechanical activation-treated precursor.Ni-Co/SPCE-C with favorable structural char-acteristics,intimate interfacial compatibility,and unique spontaneous polarization effect enhanced the migration efficiency of active hydrogen and activated water to form small water clusters,contributing to outstanding catalytic activity for aqueous-phase hydrogenation of LA to produce GVL at relatively low re-action temperature and H2 pressure.A LA conversion of 99.9%and a GVL yield of 92.3%were achieved at 160℃ and 1.5 MPa H2 over the Ni-Co/SPCE-C catalyst,which were significantly higher than those catalyzed by contrastive catalysts.A variety of tests and theoretical calculations reveal that SPCE with far-infrared emission and surface electric field was conducive to the reduction in the hydrogen spillover energy barrier,the stabilization of the transition state,and the facile exchange of H2 and water for ac-celerating WAPH.Moreover,a reasonable SPCE-reinforced WAPH mechanism was proposed to explain the enhanced aqueous hydrogenation of LA.This research can provide valuable insights into the design and development of high-performance non-noble metal catalysts for aqueous hydrogenation applications.展开更多
文摘The difficulties of washing during the dressing of kaolin ore have been analyzed, the multistep intermittent washing model has been deduced, and effective methods for dealing with the difficulties were put forward. Experimental results show that the bleaching and washing process was enhanced, the washing time was shortened and the consumption of water was reduced by means of adding flocculant.
基金the National Natural Science Foundation of China(nos.22008041 and 22178074)the Natural Science Foundation of Guangxi Province,China(nos.2019GXNSFDA245020 and 2020GXNSFGA297001).
文摘Spontaneously polarized crystals with intrinsic electric dipole moment have attracted immense interest as excellent functional materials for extensive applications.It is of great significance to engineer sustainable spontaneously polarized materials with fascinating characteristics and performance for activating air and water.Herein,a novel strategy based on the synergy of mechanical activation(MA)and biomimetic mineralization(BM)was created to construct spontaneously polarized ceramic.MA induced the structural damage of clay and promoted the dissolution of ions and the release of free proteins,contributing to the formation of silicate precursor in BM process.After high temperature firing,the silicate precursor in clay was converted to form KCa_(3)AlCa_(3)Si_(4)O_(16)(hexagonal crystal system,L^(6)symmetry type,and P63 space group)in the resulting spontaneously polarized ceramic.The non-centrosymmetric structure of KCa_(3)AlCa_(3)Si4O_(16)and the high intrinsic electric dipole moments contributed by K(1)polyhedrons resulted in high spontaneous polarization(0.2322μC/cm^(2))and far-infrared emissivity(0.951)of spontaneously polarized ceramic.In air,spontaneously polarized ceramic can activate H_(2)O and O_(2)molecules to form negative air ions owing to surface electric field.In water,spontaneously polarized ceramic can disaggregate large water clusters to form small water clusters ascribed to surface electric field and far-infrared emission;water pH can be regulated from weak acidity to approximate neutrality via the capture of electrons by H+ions to produce releasable hydrogen gas.This work provides great promise for rational design and synthesis of spontaneously polarized materials for functional applications.
基金supported by the National Natural Science Foundation of China(No.22008041)the Natural Science Foun-dation of Guangxi Province,China(Nos.2019GXNSFDA245020 and 2020GXNSFGA297001).
文摘Water-assisted proton hopping(WAPH)plays an important role in the aqueous-phase hydrogenation of levulinic acid(LA)toγ-valerolactone(GVL).In this study,based on a strategy of spontaneously polarized ceramic(SPCE)-reinforced WAPH,a Ni-Co/SPCE-C catalyst was constructed by high-temperature calci-nation of a dual mechanical activation-treated precursor.Ni-Co/SPCE-C with favorable structural char-acteristics,intimate interfacial compatibility,and unique spontaneous polarization effect enhanced the migration efficiency of active hydrogen and activated water to form small water clusters,contributing to outstanding catalytic activity for aqueous-phase hydrogenation of LA to produce GVL at relatively low re-action temperature and H2 pressure.A LA conversion of 99.9%and a GVL yield of 92.3%were achieved at 160℃ and 1.5 MPa H2 over the Ni-Co/SPCE-C catalyst,which were significantly higher than those catalyzed by contrastive catalysts.A variety of tests and theoretical calculations reveal that SPCE with far-infrared emission and surface electric field was conducive to the reduction in the hydrogen spillover energy barrier,the stabilization of the transition state,and the facile exchange of H2 and water for ac-celerating WAPH.Moreover,a reasonable SPCE-reinforced WAPH mechanism was proposed to explain the enhanced aqueous hydrogenation of LA.This research can provide valuable insights into the design and development of high-performance non-noble metal catalysts for aqueous hydrogenation applications.
