In most coastal and estuarine areas,tides easily cause surface erosion and even slope failure,resulting in severe land losses,deterioration of coastal infrastructure,and increased floods.The bio-cementation technique ...In most coastal and estuarine areas,tides easily cause surface erosion and even slope failure,resulting in severe land losses,deterioration of coastal infrastructure,and increased floods.The bio-cementation technique has been previously demonstrated to effectively improve the erosion resistance of slopes.Seawater contains magnesium ions(Mg^(2+))with a higher concentration than calcium ions(Ca^(2+));therefore,Mg^(2+)and Ca^(2+)were used together for bio-cementation in this study at various Mg^(2+)/Ca^(2+)ratios as the microbially induced magnesium and calcium precipitation(MIMCP)treatment.Slope angles,surface strengths,precipitation contents,major phases,and microscopic characteristics of precipitation were used to evaluate the treatment effects.Results showed that the MIMCP treatment markedly enhanced the erosion resistance of slopes.Decreased Mg^(2+)/Ca^(2+)ratios resulted in a smaller change in angles and fewer soil losses,especially the Mg^(2+)concentration below 0.2 M.The decreased Mg^(2+)/Ca^(2+)ratio achieved increased precipitation contents,which contributed to better erosion resistance and higher surface strengths.Additionally,the production of aragonite would benefit from elevated Mg^(2+)concentrations and a higher Ca^(2+)concentration led to more nesquehonite in magnesium precipitation crystals.The slopes with an initial angle of 53°had worse erosion resistance than the slopes with an initial angle of 35°,but the Mg^(2+)/Ca^(2+)ratios of 0.2:0.8,0.1:0.9,and 0:1.0 were effective for both slope stabilization and erosion mitigation to a great extent.The results are of great significance for the application of MIMCP to improve erosion resistance of foreshore slopes and the MIMCP technique has promising application potential in marine engineering.展开更多
In this investigation,a chelating agent of amino trimethylene phosphonic acid(ATMP) was introduced to eliminate the adverse effect of seawater in molybdenite flotation.Microflotation results presented that high flotat...In this investigation,a chelating agent of amino trimethylene phosphonic acid(ATMP) was introduced to eliminate the adverse effect of seawater in molybdenite flotation.Microflotation results presented that high flotation recovery of molybdenite was achieved in freshwater using kerosene as the collector,but it was significantly decreased in the presence of seawater when pH> 9.5.Among the main ions in seawater,magnesium and calcium ions played a more detrimental role than others.After the addition of ATMP,molybdenite floatability can restore in seawater.Zeta potential distribution and solution chemistry calculation results illustrated that the decreased molybdenite floatability was attributed to the interaction of positive Mg(OH)_(2)(s)(major) and CaOH^(+)(minor) components with the molybdenite surface.The magnesium/calcium ions of positive components of Mg(OH)_(2)(s) and CaOH^(+) interacted with the ionized species of ATMP and then produced ATMP-calcium/magnesium complex,leading to the electrostatic repulsion between molybdenite and ATMP-calcium/magnesium complex that was restoring the molybdenite flotation.Hence,the ATMP can be utilized as an appropriate reagent to improve molybdenite flotation in seawater.展开更多
A phosphetase that hydrolyses phosphate monoesters has been Isolated from wheat thylakold membranes. Biochemical properties and inhibition kinetics of the phosphatase were Investigated using several Ions, organlc solv...A phosphetase that hydrolyses phosphate monoesters has been Isolated from wheat thylakold membranes. Biochemical properties and inhibition kinetics of the phosphatase were Investigated using several Ions, organlc solvents, and Inhlbltors. Wheat （Trltlcum aestivum L. cv. PH82-2-2） thylakold membrane phosphatase activity was activated by Mg^2＋, Ca^2＋, and Fe^2＋ and was inhibited by Mn^2＋ and Cu^2＋. For example, enzyme activity was acUvated 34.81% by 2 mmol/l. Mg^2＋, but was Inhibited 22.3% and 8.5% by 2 and 1 mmol/L Cu^2＋, respectively. Methanol, ethanol and glycol were all able to activate enzyme activity. Enzyme activity was activated 58.5%, 48.2%, and 8.7% by 40% ethanol, methanol and glycol, respectively. From these results, It can be seen that the degree of actlvetlon of the phosphetase was greatest for ethanol and the type of acUvatlon was uncompetltlve. Moreover, the activity of the thylakold membrane phosphetase was Inhibited by molybdate, vanadete, phosphate, and fluoride and the type of Inhibition produced by these elements was uncompetltlve, non-competitive, competltlve and mixed, respectively.展开更多
基金funded by the National Natural Science Foundation of China(Grant No.51578147)Fundamental Research Funds for the Central Universities(Grant No.2242020R20025)Ningxia Science and Technology Department(Grant No.2020BFG02014).
文摘In most coastal and estuarine areas,tides easily cause surface erosion and even slope failure,resulting in severe land losses,deterioration of coastal infrastructure,and increased floods.The bio-cementation technique has been previously demonstrated to effectively improve the erosion resistance of slopes.Seawater contains magnesium ions(Mg^(2+))with a higher concentration than calcium ions(Ca^(2+));therefore,Mg^(2+)and Ca^(2+)were used together for bio-cementation in this study at various Mg^(2+)/Ca^(2+)ratios as the microbially induced magnesium and calcium precipitation(MIMCP)treatment.Slope angles,surface strengths,precipitation contents,major phases,and microscopic characteristics of precipitation were used to evaluate the treatment effects.Results showed that the MIMCP treatment markedly enhanced the erosion resistance of slopes.Decreased Mg^(2+)/Ca^(2+)ratios resulted in a smaller change in angles and fewer soil losses,especially the Mg^(2+)concentration below 0.2 M.The decreased Mg^(2+)/Ca^(2+)ratio achieved increased precipitation contents,which contributed to better erosion resistance and higher surface strengths.Additionally,the production of aragonite would benefit from elevated Mg^(2+)concentrations and a higher Ca^(2+)concentration led to more nesquehonite in magnesium precipitation crystals.The slopes with an initial angle of 53°had worse erosion resistance than the slopes with an initial angle of 35°,but the Mg^(2+)/Ca^(2+)ratios of 0.2:0.8,0.1:0.9,and 0:1.0 were effective for both slope stabilization and erosion mitigation to a great extent.The results are of great significance for the application of MIMCP to improve erosion resistance of foreshore slopes and the MIMCP technique has promising application potential in marine engineering.
基金the support of the National Natural Science Foundation of China (No. 51874150)the Natural Science Foundation of Hubei Province of China (ZRMS2021000085)+1 种基金the Fundamental Research Funds for the Central Universities (2021IVA039)the Open Foundation of State Key Laboratory of Mineral Processing, BGRIMM Technology (No. BGRIMM-KJSKL2021-22)。
文摘In this investigation,a chelating agent of amino trimethylene phosphonic acid(ATMP) was introduced to eliminate the adverse effect of seawater in molybdenite flotation.Microflotation results presented that high flotation recovery of molybdenite was achieved in freshwater using kerosene as the collector,but it was significantly decreased in the presence of seawater when pH> 9.5.Among the main ions in seawater,magnesium and calcium ions played a more detrimental role than others.After the addition of ATMP,molybdenite floatability can restore in seawater.Zeta potential distribution and solution chemistry calculation results illustrated that the decreased molybdenite floatability was attributed to the interaction of positive Mg(OH)_(2)(s)(major) and CaOH^(+)(minor) components with the molybdenite surface.The magnesium/calcium ions of positive components of Mg(OH)_(2)(s) and CaOH^(+) interacted with the ionized species of ATMP and then produced ATMP-calcium/magnesium complex,leading to the electrostatic repulsion between molybdenite and ATMP-calcium/magnesium complex that was restoring the molybdenite flotation.Hence,the ATMP can be utilized as an appropriate reagent to improve molybdenite flotation in seawater.
文摘A phosphetase that hydrolyses phosphate monoesters has been Isolated from wheat thylakold membranes. Biochemical properties and inhibition kinetics of the phosphatase were Investigated using several Ions, organlc solvents, and Inhlbltors. Wheat （Trltlcum aestivum L. cv. PH82-2-2） thylakold membrane phosphatase activity was activated by Mg^2＋, Ca^2＋, and Fe^2＋ and was inhibited by Mn^2＋ and Cu^2＋. For example, enzyme activity was acUvated 34.81% by 2 mmol/l. Mg^2＋, but was Inhibited 22.3% and 8.5% by 2 and 1 mmol/L Cu^2＋, respectively. Methanol, ethanol and glycol were all able to activate enzyme activity. Enzyme activity was activated 58.5%, 48.2%, and 8.7% by 40% ethanol, methanol and glycol, respectively. From these results, It can be seen that the degree of actlvetlon of the phosphetase was greatest for ethanol and the type of acUvatlon was uncompetltlve. Moreover, the activity of the thylakold membrane phosphetase was Inhibited by molybdate, vanadete, phosphate, and fluoride and the type of Inhibition produced by these elements was uncompetltlve, non-competitive, competltlve and mixed, respectively.
