The adsorption of uranium(Ⅵ)on the manganese oxide coated zeolite(MOCZ)from aqueous solution was investigated in a fixed-bed column.The experiments were conducted to investigate the effects of bed height,flow rate,pa...The adsorption of uranium(Ⅵ)on the manganese oxide coated zeolite(MOCZ)from aqueous solution was investigated in a fixed-bed column.The experiments were conducted to investigate the effects of bed height,flow rate,particle size,initial concentration of uranium(Ⅵ),initial pH,presence of salt and competitive ions.The U-uptake by MOCZ increased with initial uranium(Ⅵ)concentration and bed height,but decreased as the flow rate and particle size increased.In the presence of salt and competitive ions,the breakthrough time was shorter.The adsorption capacity reached a maximum at pH of 6.3.The Thomas model was applied to the experimental data to determine the characteristic parameters of the column for process design using linear regression.The breakthrough curves calculated from the model were in good agreement with the experimental data.The BDST model was used to study the influence of bed height on the adsorption of uranium(Ⅵ).Desorption of uranium(Ⅵ)in the MOCZ column was investigated.The column could be used for at least four adsorption-desorption cycles using 0.1mol.L-1 NaHCO3 solution as the elution.After desorption and regeneration with deionized water,MOCZ could be reused to adsorb uranium(Ⅵ)at a comparable capacity.Compared to raw zeolite,MOCZ showed better capacity for uranium(Ⅵ)removal.展开更多
It is observed that the adsorption of chromium are greater on kaolinite minerals, red soil (R) and laterite (L) colloids than that on montmorillonite, indicotic black (IB) and yellow brown (YB) soil colloids. The adso...It is observed that the adsorption of chromium are greater on kaolinite minerals, red soil (R) and laterite (L) colloids than that on montmorillonite, indicotic black (IB) and yellow brown (YB) soil colloids. The adsorption process of Cr Ⅵ on these media can be further described by Langmuir or Freundlich equation quite well. The adsorption reaction of Cr Ⅵ is fast, and the adsorption equilibrium can be reached within the first two hours in moderate temperature. The adsorption quantity of Cr Ⅵ to kaolinite mineral increased with the increasing pH in the range of 2.0 to 7.0, then decreased at higher pH. But it showed some consistence among the four soil colloids. The lower the pH, the stronger the adsorption. The possible mechanisms are further discussed here. Meanwhile the influence of temperature on Cr Ⅵ adsorption on different soil colloid and clay minerals are also investigated.展开更多
Background:The effect of short-segment decompression/fusion versus long-segment decompression/fusion and osteotomy for Lenke-Silva type Ⅵ adult degenerative scoliosis(ADS)has not been clarified.This study aimed to co...Background:The effect of short-segment decompression/fusion versus long-segment decompression/fusion and osteotomy for Lenke-Silva type Ⅵ adult degenerative scoliosis(ADS)has not been clarified.This study aimed to compare the clinical and radiographic results of short-segment fusion vs.long-segment fusion and osteotomy for patients with Lenke-Silva type Ⅵ ADS.Methods:Data of 28 patients who underwent spinal surgery for ADS from January 2012 to January 2014 in the General Hospital of Northern Theater Command were reviewed.Of the 28 patients,12 received long-segment fusion and osteotomy and 16 received short-segment fusion.Radiographic imaging parameters and clinical outcomes,including the sagittal vertical axis(SVA),lumbar lordosis(LL)angle,pelvic tilt(PT),sacral slope(SS),the visual analog scale(VAS),Japanese Orthopedic Association(JOA),Oswestry disability index(ODI),and lumbar stiffness disability index(LSDI)scores,were recorded.The difference between groups was compared using the dependent t test or Chi-squared test.Results:The Cobb and LL angles and SVA improved in both groups;however,PT and SS angles did not improve following short fusion.There were significant differences in the post-operative SVA(26.8±5.4mm vs.47.5±7.6 mm,t=–8.066,P<0.001),PT(14.7±1.8°vs.29.1±3.4°,t=–13.277,P<0.001),and SS(39.8±7.2°vs.26.1±3.3°,t=6.175,P<0.001)between the long and short fusion groups.All patients had improved ODI,JOA,and VAS scores post-operatively(all P<0.001),with no significant difference between the groups(all P>0.05).The post-operative LSDI score was 3.5±0.5 in the long fusion group,which was significantly higher than that of the short fusion group(1.4±0.7;P<0.001).Conclusions:The clinical outcomes of patients with Lenke-Silva type Ⅵ ADS who underwent short-segment decompression/fusion were comparable to those of patients who underwent long-segment decompression/fusion and osteotomy despite poor correction of sagittal imbalance.Moreover,short-segment decompression/fusion showed a short operation t展开更多
基金Supported by the National Science Foundation for Postdoctoral Sciemists of China （20070420811） and the Science and Technology Department of Henan Province in China （200510459016）.
文摘The adsorption of uranium(Ⅵ)on the manganese oxide coated zeolite(MOCZ)from aqueous solution was investigated in a fixed-bed column.The experiments were conducted to investigate the effects of bed height,flow rate,particle size,initial concentration of uranium(Ⅵ),initial pH,presence of salt and competitive ions.The U-uptake by MOCZ increased with initial uranium(Ⅵ)concentration and bed height,but decreased as the flow rate and particle size increased.In the presence of salt and competitive ions,the breakthrough time was shorter.The adsorption capacity reached a maximum at pH of 6.3.The Thomas model was applied to the experimental data to determine the characteristic parameters of the column for process design using linear regression.The breakthrough curves calculated from the model were in good agreement with the experimental data.The BDST model was used to study the influence of bed height on the adsorption of uranium(Ⅵ).Desorption of uranium(Ⅵ)in the MOCZ column was investigated.The column could be used for at least four adsorption-desorption cycles using 0.1mol.L-1 NaHCO3 solution as the elution.After desorption and regeneration with deionized water,MOCZ could be reused to adsorb uranium(Ⅵ)at a comparable capacity.Compared to raw zeolite,MOCZ showed better capacity for uranium(Ⅵ)removal.
文摘It is observed that the adsorption of chromium are greater on kaolinite minerals, red soil (R) and laterite (L) colloids than that on montmorillonite, indicotic black (IB) and yellow brown (YB) soil colloids. The adsorption process of Cr Ⅵ on these media can be further described by Langmuir or Freundlich equation quite well. The adsorption reaction of Cr Ⅵ is fast, and the adsorption equilibrium can be reached within the first two hours in moderate temperature. The adsorption quantity of Cr Ⅵ to kaolinite mineral increased with the increasing pH in the range of 2.0 to 7.0, then decreased at higher pH. But it showed some consistence among the four soil colloids. The lower the pH, the stronger the adsorption. The possible mechanisms are further discussed here. Meanwhile the influence of temperature on Cr Ⅵ adsorption on different soil colloid and clay minerals are also investigated.
文摘Background:The effect of short-segment decompression/fusion versus long-segment decompression/fusion and osteotomy for Lenke-Silva type Ⅵ adult degenerative scoliosis(ADS)has not been clarified.This study aimed to compare the clinical and radiographic results of short-segment fusion vs.long-segment fusion and osteotomy for patients with Lenke-Silva type Ⅵ ADS.Methods:Data of 28 patients who underwent spinal surgery for ADS from January 2012 to January 2014 in the General Hospital of Northern Theater Command were reviewed.Of the 28 patients,12 received long-segment fusion and osteotomy and 16 received short-segment fusion.Radiographic imaging parameters and clinical outcomes,including the sagittal vertical axis(SVA),lumbar lordosis(LL)angle,pelvic tilt(PT),sacral slope(SS),the visual analog scale(VAS),Japanese Orthopedic Association(JOA),Oswestry disability index(ODI),and lumbar stiffness disability index(LSDI)scores,were recorded.The difference between groups was compared using the dependent t test or Chi-squared test.Results:The Cobb and LL angles and SVA improved in both groups;however,PT and SS angles did not improve following short fusion.There were significant differences in the post-operative SVA(26.8±5.4mm vs.47.5±7.6 mm,t=–8.066,P<0.001),PT(14.7±1.8°vs.29.1±3.4°,t=–13.277,P<0.001),and SS(39.8±7.2°vs.26.1±3.3°,t=6.175,P<0.001)between the long and short fusion groups.All patients had improved ODI,JOA,and VAS scores post-operatively(all P<0.001),with no significant difference between the groups(all P>0.05).The post-operative LSDI score was 3.5±0.5 in the long fusion group,which was significantly higher than that of the short fusion group(1.4±0.7;P<0.001).Conclusions:The clinical outcomes of patients with Lenke-Silva type Ⅵ ADS who underwent short-segment decompression/fusion were comparable to those of patients who underwent long-segment decompression/fusion and osteotomy despite poor correction of sagittal imbalance.Moreover,short-segment decompression/fusion showed a short operation t
