<span style="font-family:Verdana;">Because of various disadvantages of chemical synthesis processes, these</span><span> </span><span style="font-family:Verdana;">days ...<span style="font-family:Verdana;">Because of various disadvantages of chemical synthesis processes, these</span><span> </span><span style="font-family:Verdana;">days people are attracting towards green synthesis processes as it is devoid of toxic by-products, cost-effective and eco-friendly. In this study, a simple green synthesis method is applied for the synthesis of magnetite (Fe</span><sub><span style="vertical-align:sub;font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">O</span><sub><span style="vertical-align:sub;font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">) nanoparticles (MNPs) by co-precipitation of FeCl</span><sub><span style="vertical-align:sub;font-family:Verdana;">3·</span></sub><span style="font-family:Verdana;">6H</span><sub><span style="vertical-align:sub;font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">O and FeSO</span><sub><span style="vertical-align:sub;font-family:Verdana;">4·</span></sub><span style="font-family:Verdana;">7H</span><sub><span style="vertical-align:sub;font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">O in the molar ratio of 2:1 using </span><span><i></i></span><i><span style="font-family:Verdana;">Azadirachta indica</span><span></span></i><span style="font-family:Verdana;"> leaves extract under nitrogen environment. FTIR, XRD, SEM etc. were used to characterize the synthesized MNPs. Batch adsorption experiments were carried out to determine adsorption equilibrium of As(V) as a function of pH, adsorbent dose, contact time and different initial concentrations. Kinetics results were best describe</span><span style="font-family:Verdana;">d</span><span style="font-family:Verdana;"> by pseudo-second order model with rate constant value 0.0052 g/(mg·min). The equilibrium adsorption isotherm was best fitted with Langmuir adsorption isotherm model. The maximum adsorption capacity was found to be 62.89 mg/g at pH 2. MNPs showed </span><span style="font-family:Verdana;">a </span><span style="font-family:Verdana;">high affinity for As(V) and avoids filtration for solid-liquid separation, thus it would be employed as a promising material </span><span style="font-family:Verdana;">for </span><span style="font-family:Verdana;">the removal of As(V) from water.</span>展开更多
In this study,ferric nitrate modified carbon nanotube composites (FCNT) were prepared by isovolumetric impregnation using carbon nanotubes (CNTs) as the carrier and ferric nitrates the active agent.The batch experimen...In this study,ferric nitrate modified carbon nanotube composites (FCNT) were prepared by isovolumetric impregnation using carbon nanotubes (CNTs) as the carrier and ferric nitrates the active agent.The batch experiments showed that FCNT could effectively oxidize As(III) to As(V) and react with it to form stable iron arsenate precipitates.When the dosage of FCNT was 0.1 g·L^(–1),pH value was 5–6,reaction temperature was 35℃ and reaction time was 2 h,the best arsenic removal effect could be achieved,and the removal rate of As(V) could reach 99.1%,which was always higher than 90%under acidic conditions.The adsorption results of FCNT were found to be consistent with Langmuir adsorption by static adsorption isotherm fitting,and the maximum adsorption capacity reached 118.3 mg·g^(-1).The material phase and property analysis by scanning electron microscopy,Brunauer–Emmett–Teller,Fourier transform infrared spectoscopy,X-ray photoelectron spectroscopy and other characterization methods,as well as adsorption isotherm modeling,were used to explore the adsorption mechanism of FCNT on arsenic.It was found that FCNT has microporous structure and nanostructure,and iron nanoparticles are loosely distributed on CNTs,which makes the material have good oxidation,adsorption and magnetic separation properties.Arsenic migrates on the surface of FCNT composites is mainly removed by forming insoluble compounds and co-precipitation.All the results show that FCNT treats arsenic at low cost with high adsorption efficiency,and the results also provide the experimental data basis and theoretical basis for arsenic contamination in groundwater.展开更多
基金Projects(2019YFC0408305,2018YFC1901601)supported by the National Key Scientific Research of ChinaProject(2018CX036)supported by the Innovation-Driven Plan of Central South University,ChinaProject(2018TP1002)supported by the Key Laboratory of Hunan Province for Clean and Efficient Utilization of Strategic Calcium-Containing Mineral Resources,China。
文摘<span style="font-family:Verdana;">Because of various disadvantages of chemical synthesis processes, these</span><span> </span><span style="font-family:Verdana;">days people are attracting towards green synthesis processes as it is devoid of toxic by-products, cost-effective and eco-friendly. In this study, a simple green synthesis method is applied for the synthesis of magnetite (Fe</span><sub><span style="vertical-align:sub;font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">O</span><sub><span style="vertical-align:sub;font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">) nanoparticles (MNPs) by co-precipitation of FeCl</span><sub><span style="vertical-align:sub;font-family:Verdana;">3·</span></sub><span style="font-family:Verdana;">6H</span><sub><span style="vertical-align:sub;font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">O and FeSO</span><sub><span style="vertical-align:sub;font-family:Verdana;">4·</span></sub><span style="font-family:Verdana;">7H</span><sub><span style="vertical-align:sub;font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">O in the molar ratio of 2:1 using </span><span><i></i></span><i><span style="font-family:Verdana;">Azadirachta indica</span><span></span></i><span style="font-family:Verdana;"> leaves extract under nitrogen environment. FTIR, XRD, SEM etc. were used to characterize the synthesized MNPs. Batch adsorption experiments were carried out to determine adsorption equilibrium of As(V) as a function of pH, adsorbent dose, contact time and different initial concentrations. Kinetics results were best describe</span><span style="font-family:Verdana;">d</span><span style="font-family:Verdana;"> by pseudo-second order model with rate constant value 0.0052 g/(mg·min). The equilibrium adsorption isotherm was best fitted with Langmuir adsorption isotherm model. The maximum adsorption capacity was found to be 62.89 mg/g at pH 2. MNPs showed </span><span style="font-family:Verdana;">a </span><span style="font-family:Verdana;">high affinity for As(V) and avoids filtration for solid-liquid separation, thus it would be employed as a promising material </span><span style="font-family:Verdana;">for </span><span style="font-family:Verdana;">the removal of As(V) from water.</span>
基金supported by the National Natural Science Foundation of China (NSFC) on the micro behavior of heavy metal migration and transformation in lead–zinc tailings and its nano micro scale high targeted stabilization mechanism (51968033)the National Key Research and Development Program “long-term solidification of heavy metal tailings pollution/environmental functional materials, technologies and equipment of stabilizers” (2018YFC1801702)。
文摘In this study,ferric nitrate modified carbon nanotube composites (FCNT) were prepared by isovolumetric impregnation using carbon nanotubes (CNTs) as the carrier and ferric nitrates the active agent.The batch experiments showed that FCNT could effectively oxidize As(III) to As(V) and react with it to form stable iron arsenate precipitates.When the dosage of FCNT was 0.1 g·L^(–1),pH value was 5–6,reaction temperature was 35℃ and reaction time was 2 h,the best arsenic removal effect could be achieved,and the removal rate of As(V) could reach 99.1%,which was always higher than 90%under acidic conditions.The adsorption results of FCNT were found to be consistent with Langmuir adsorption by static adsorption isotherm fitting,and the maximum adsorption capacity reached 118.3 mg·g^(-1).The material phase and property analysis by scanning electron microscopy,Brunauer–Emmett–Teller,Fourier transform infrared spectoscopy,X-ray photoelectron spectroscopy and other characterization methods,as well as adsorption isotherm modeling,were used to explore the adsorption mechanism of FCNT on arsenic.It was found that FCNT has microporous structure and nanostructure,and iron nanoparticles are loosely distributed on CNTs,which makes the material have good oxidation,adsorption and magnetic separation properties.Arsenic migrates on the surface of FCNT composites is mainly removed by forming insoluble compounds and co-precipitation.All the results show that FCNT treats arsenic at low cost with high adsorption efficiency,and the results also provide the experimental data basis and theoretical basis for arsenic contamination in groundwater.
