The study focused on the effect of several typical competing solutes on removal of arsenic with Fe2O3 and Al2O3. The test results indicate that chloride, nitrate and sulfate did not have detectable effects, and that s...The study focused on the effect of several typical competing solutes on removal of arsenic with Fe2O3 and Al2O3. The test results indicate that chloride, nitrate and sulfate did not have detectable effects, and that selenium（Ⅳ） （Se（Ⅳ）） and vanadium（Ⅴ） （V（Ⅴ）） showed slight effects on the adsorption of As（Ⅴ） with Fe2O3. The results also showed that adsorption of As（Ⅴ） on A12O3 was not affected by chloride and nitrate anions, but slightly by Se（Ⅳ） and V（Ⅴ） ions. Unlike the adsorption of As（Ⅴ） with Fe2O3, that with Fe2O3 was affected by the presence of sulfate in water solutions. Both phosphate and silica have significant adverse effects on the adsorption of As（Ⅴ） adsorption with Fe2O3 and Al2O3. Compared to the other tested anions, phosphate anion was found to be the most prominent solute affecting the As（Ⅴ） adsorption with Fe2O3 and Al2O3. In general, Fe2O3 has a better performance than Al2O3 in removal of As（Ⅴ） within a water environment where multi competing solutes are present.展开更多
High residual concentration of arsenic and fluoride is a tricky problem to be solved in the process of reinjection after geothermal water utilization.We develop a method to simultaneously remove As(V)and F-from geothe...High residual concentration of arsenic and fluoride is a tricky problem to be solved in the process of reinjection after geothermal water utilization.We develop a method to simultaneously remove As(V)and F-from geothermal water using magnetic Fe_(3)O_(4)@MgO adsorbent,fabricated via a one-step method.The effects of pH,contact time,adsorbent dose and temperature on the removal efficiency were investigated systematically.The results show that the Fe_(3)O_(4)@MgO composite has a wide range of pH(2-11),ultrafast removal dynamics(As(V):2 min;F-:30 min),and high removal efficiency(As(V):99.9%;F-:96.6%).The adsorption kinetics follows the pseudo-secondorder kinetics model,and the adsorption isotherm model fits Freundlich.The adsorption capacity of As(V)and F-can reach 123 and 98.4 mg/g,respectively.The exchange of As(V)and F-with Mg-hydroxyl groups hydrolysis by MgO was determined the adsorption mechanism.The Fe_(3)O_(4)@MgO adsorbent was capable of achieving the adsorption efficiency as high as 99.9%for As(V)and 97.3%for F-in real geothermal water,respectively.Hence,the proposed Fe_(3)O_(4)@MgO composite exhibited as an excellent adsorbent for the remediation of As-and F-contaminated geothermal water.展开更多
文摘The study focused on the effect of several typical competing solutes on removal of arsenic with Fe2O3 and Al2O3. The test results indicate that chloride, nitrate and sulfate did not have detectable effects, and that selenium（Ⅳ） （Se（Ⅳ）） and vanadium（Ⅴ） （V（Ⅴ）） showed slight effects on the adsorption of As（Ⅴ） with Fe2O3. The results also showed that adsorption of As（Ⅴ） on A12O3 was not affected by chloride and nitrate anions, but slightly by Se（Ⅳ） and V（Ⅴ） ions. Unlike the adsorption of As（Ⅴ） with Fe2O3, that with Fe2O3 was affected by the presence of sulfate in water solutions. Both phosphate and silica have significant adverse effects on the adsorption of As（Ⅴ） adsorption with Fe2O3 and Al2O3. Compared to the other tested anions, phosphate anion was found to be the most prominent solute affecting the As（Ⅴ） adsorption with Fe2O3 and Al2O3. In general, Fe2O3 has a better performance than Al2O3 in removal of As（Ⅴ） within a water environment where multi competing solutes are present.
基金funded by the Second Comprehensive Scientific Investigation Project of Qinghai-Tibet Plateau(No.2019QZKK0603)the National Natural Science Foundation of China(No.22066022)+2 种基金Science and Technology Plan Projects of Tibet Autonomous Region(No.ZYYD2022000255)Key Projects of“Science and Technology Help Economy 2020”(No.SQ2020YFF0423891)Key Projects of Solid Waste Recycling(No.2019YFC1904103-04)。
文摘High residual concentration of arsenic and fluoride is a tricky problem to be solved in the process of reinjection after geothermal water utilization.We develop a method to simultaneously remove As(V)and F-from geothermal water using magnetic Fe_(3)O_(4)@MgO adsorbent,fabricated via a one-step method.The effects of pH,contact time,adsorbent dose and temperature on the removal efficiency were investigated systematically.The results show that the Fe_(3)O_(4)@MgO composite has a wide range of pH(2-11),ultrafast removal dynamics(As(V):2 min;F-:30 min),and high removal efficiency(As(V):99.9%;F-:96.6%).The adsorption kinetics follows the pseudo-secondorder kinetics model,and the adsorption isotherm model fits Freundlich.The adsorption capacity of As(V)and F-can reach 123 and 98.4 mg/g,respectively.The exchange of As(V)and F-with Mg-hydroxyl groups hydrolysis by MgO was determined the adsorption mechanism.The Fe_(3)O_(4)@MgO adsorbent was capable of achieving the adsorption efficiency as high as 99.9%for As(V)and 97.3%for F-in real geothermal water,respectively.Hence,the proposed Fe_(3)O_(4)@MgO composite exhibited as an excellent adsorbent for the remediation of As-and F-contaminated geothermal water.
