Two-dimensional(2D)catalytic ozonation membranes are promising for the treatment of micropollutants in wastewater due to simultaneous ozone-catalyzed degradation and membrane filtration processes.However,it remains ch...Two-dimensional(2D)catalytic ozonation membranes are promising for the treatment of micropollutants in wastewater due to simultaneous ozone-catalyzed degradation and membrane filtration processes.However,it remains challenging for 2D catalytic ozonation membranes to efficiently degrade micropollutants due to low mass-transfer efficiency and poor catalytic activity.Herein,Fe/Mn bimetallic metal-organic framework(MOF)intercalated lamellar MnO_(2) membranes with fast and robust ozone-catalyzed mass-transfer channels were developed on the surface of the hollow fiber ceramic membrane(HFCM)to obtain 2D Fe/Mn-MOF@MnO_(2)-HFCM for efficiently degrading micropollutants in wastewater.The intercalation of Fe/Mn-MOF expanded the interlayer spacing of the MnO_(2) membrane,thereby providing abundant transport channels for rapid passage of water.More notably,the Fe/Mn-MOF provided enriched reactive sites as well as high electron transfer efficiency based on the redox cycling between Mn^(3+)/Mn^(4+) and Fe^(2+)/Fe^(3+),ensuring the effective catalytic oxidative degradation of micropollutants including tetracycline hydrochloride(TCH),methylene blue,and methyl blue.Moreover,the carboxyl groups on the MOF formed covalent bonds(-COO-)with the hydroxyl groups in MnO_(2) between layers,which increased the interaction between MnO_(2) nanosheets to form stable interlayer channels.Specifically,the optimal composite membrane achieved a high removal rate of TCH micropollutant(93.4%),high water treatment capacity(282 L·m^(-2)·h^(-1)·MPa^(-1)),and excellent longterm stability(1200 min).This study provides a simple and easily scalable strategy to construct fast,efficient,and stable 2D catalytic mass-transfer channels for the efficient treatment of micropollutants in wastewater.展开更多
利用共沉淀法制备了四组分的Cu Zn Al Mn和Cu Zn Al Ce催化剂以及三组分的Cu Zn Al催化剂。利用组成H2/CO/CO2/N2=66/27/3/4(体积比)的富CO原料气对催化剂进行了活性评价,并研究了温度、压力和空速等反应条件对催化剂活性的影响。结果...利用共沉淀法制备了四组分的Cu Zn Al Mn和Cu Zn Al Ce催化剂以及三组分的Cu Zn Al催化剂。利用组成H2/CO/CO2/N2=66/27/3/4(体积比)的富CO原料气对催化剂进行了活性评价,并研究了温度、压力和空速等反应条件对催化剂活性的影响。结果发现添加适量的锰助剂能显著提高催化剂的活性和热稳定性。利用SEM和XRD方法进行了催化剂的结构和形貌表征,同样表明锰助剂可以起到阻止CuO晶粒长大和促进CuO分散作用。利用富CO2的生物质原料气体积比为H2/CO/CO2/N2=50/25/20/5对Cu Zn Al Mn催化剂进行的评价表明:Cu Zn Al Mn催化剂上CO/CO2加氢合成甲醇的甲醇产率和选择性均有下降,在试验范围内,甲醇产率下降11%～25%,选择性为93%～95%。展开更多
【目的】探索建立基于近红外光谱技术的土壤微量元素监测技术。【方法】采集三峡库区(重庆)主要加工甜橙基地果园背景土壤样品168个,随机选取100个作为建模样本,其余为检验样本;测定所有样本的近红外反射光谱和土壤Fe、Mn、Zn全含量;运...【目的】探索建立基于近红外光谱技术的土壤微量元素监测技术。【方法】采集三峡库区(重庆)主要加工甜橙基地果园背景土壤样品168个,随机选取100个作为建模样本,其余为检验样本;测定所有样本的近红外反射光谱和土壤Fe、Mn、Zn全含量;运用最佳光谱预处理方法和偏最小二乘法(partial least square method,PLS)及内部交叉验证方法建立校正模型,并进行模型精度检验。【结果】变量标准化(standard normal variables,SNV)为土壤Fe、Mn、Zn含量近红外光谱预测的最佳光谱预处理方法;运用SNV光谱预处理和偏最小二乘法(PLS)及内部交叉验证法建立的土壤Fe、Mn、Zn含量校正模型,95%置信区间内的预测精度分别为92.65%、95.59%和95.59%。【结论】利用近红外反射光谱技术进行土壤Fe、Mn、Zn含量检测可行且精度较高。展开更多
为了有效去除水中的铅离子,实验制备以MnO2为吸附表面的磁性Fe/Mn纳米复合吸附剂,并进行了吸附实验研究,分析pH、温度等参数对吸附的影响.结果发现,从298 K Langmuir等温吸附曲线可以计算出Fe/Mn复合吸附剂对Pb2+的饱和吸附量(Q0=118.06...为了有效去除水中的铅离子,实验制备以MnO2为吸附表面的磁性Fe/Mn纳米复合吸附剂,并进行了吸附实验研究,分析pH、温度等参数对吸附的影响.结果发现,从298 K Langmuir等温吸附曲线可以计算出Fe/Mn复合吸附剂对Pb2+的饱和吸附量(Q0=118.06 mg/L).复合吸附剂对Pb2+的吸附总量正比于pH(1.5～5)和温度(303～323 K).在研究纳米复合材料对铅离子的吸附动力学实验中发现,纳米复合材料和铅离子之间的吸附动力学符合假二级模型,通过相关热力学研究计算得到纳米材料和铅离子之间为吸热反应.展开更多
The electrochemical behavior of Mn (Ⅲ)/Mn(Ⅱ)ion-pair on platinum electrode in acid media were studied by cyclic voltammetry.It was demonstrated that the redox process of Mn(Ⅲ)/Mn(Ⅱ) pair was a simple pseudo-revers...The electrochemical behavior of Mn (Ⅲ)/Mn(Ⅱ)ion-pair on platinum electrode in acid media were studied by cyclic voltammetry.It was demonstrated that the redox process of Mn(Ⅲ)/Mn(Ⅱ) pair was a simple pseudo-reversible one-electron reaction between Mn(Ⅲ) and Mn(Ⅱ).The electrochemical kinetics of the redox reaction on static Pt electrode was a mass transfer controlled one.The calculated diffusion coefficient of Mn(Ⅱ) was 1.48×10 -6cm 2/s.展开更多
基金financially supported by the Fundamental Research Funds for the Central Universities,China(No.2020CDJDPT001)the Chongqing Natural Science Foundation,China(No.cstc2021jcyj-msxm X0699)。
基金supported by the National Key Research and Development Program(2021YFB3801303)the National Natural Science Foundation of China(22408161,21921006)+1 种基金the Key Research and Development Program of Jiangsu Provincial Department of Science and Technology(BE2022033-3)the State Key Laboratory of Materials-Oriented Chemical Engineering(SKL-MCE-22A03).
文摘Two-dimensional(2D)catalytic ozonation membranes are promising for the treatment of micropollutants in wastewater due to simultaneous ozone-catalyzed degradation and membrane filtration processes.However,it remains challenging for 2D catalytic ozonation membranes to efficiently degrade micropollutants due to low mass-transfer efficiency and poor catalytic activity.Herein,Fe/Mn bimetallic metal-organic framework(MOF)intercalated lamellar MnO_(2) membranes with fast and robust ozone-catalyzed mass-transfer channels were developed on the surface of the hollow fiber ceramic membrane(HFCM)to obtain 2D Fe/Mn-MOF@MnO_(2)-HFCM for efficiently degrading micropollutants in wastewater.The intercalation of Fe/Mn-MOF expanded the interlayer spacing of the MnO_(2) membrane,thereby providing abundant transport channels for rapid passage of water.More notably,the Fe/Mn-MOF provided enriched reactive sites as well as high electron transfer efficiency based on the redox cycling between Mn^(3+)/Mn^(4+) and Fe^(2+)/Fe^(3+),ensuring the effective catalytic oxidative degradation of micropollutants including tetracycline hydrochloride(TCH),methylene blue,and methyl blue.Moreover,the carboxyl groups on the MOF formed covalent bonds(-COO-)with the hydroxyl groups in MnO_(2) between layers,which increased the interaction between MnO_(2) nanosheets to form stable interlayer channels.Specifically,the optimal composite membrane achieved a high removal rate of TCH micropollutant(93.4%),high water treatment capacity(282 L·m^(-2)·h^(-1)·MPa^(-1)),and excellent longterm stability(1200 min).This study provides a simple and easily scalable strategy to construct fast,efficient,and stable 2D catalytic mass-transfer channels for the efficient treatment of micropollutants in wastewater.
文摘利用共沉淀法制备了四组分的Cu Zn Al Mn和Cu Zn Al Ce催化剂以及三组分的Cu Zn Al催化剂。利用组成H2/CO/CO2/N2=66/27/3/4(体积比)的富CO原料气对催化剂进行了活性评价,并研究了温度、压力和空速等反应条件对催化剂活性的影响。结果发现添加适量的锰助剂能显著提高催化剂的活性和热稳定性。利用SEM和XRD方法进行了催化剂的结构和形貌表征,同样表明锰助剂可以起到阻止CuO晶粒长大和促进CuO分散作用。利用富CO2的生物质原料气体积比为H2/CO/CO2/N2=50/25/20/5对Cu Zn Al Mn催化剂进行的评价表明:Cu Zn Al Mn催化剂上CO/CO2加氢合成甲醇的甲醇产率和选择性均有下降,在试验范围内,甲醇产率下降11%～25%,选择性为93%～95%。
文摘【目的】探索建立基于近红外光谱技术的土壤微量元素监测技术。【方法】采集三峡库区(重庆)主要加工甜橙基地果园背景土壤样品168个,随机选取100个作为建模样本,其余为检验样本;测定所有样本的近红外反射光谱和土壤Fe、Mn、Zn全含量;运用最佳光谱预处理方法和偏最小二乘法(partial least square method,PLS)及内部交叉验证方法建立校正模型,并进行模型精度检验。【结果】变量标准化(standard normal variables,SNV)为土壤Fe、Mn、Zn含量近红外光谱预测的最佳光谱预处理方法;运用SNV光谱预处理和偏最小二乘法(PLS)及内部交叉验证法建立的土壤Fe、Mn、Zn含量校正模型,95%置信区间内的预测精度分别为92.65%、95.59%和95.59%。【结论】利用近红外反射光谱技术进行土壤Fe、Mn、Zn含量检测可行且精度较高。
文摘为了有效去除水中的铅离子,实验制备以MnO2为吸附表面的磁性Fe/Mn纳米复合吸附剂,并进行了吸附实验研究,分析pH、温度等参数对吸附的影响.结果发现,从298 K Langmuir等温吸附曲线可以计算出Fe/Mn复合吸附剂对Pb2+的饱和吸附量(Q0=118.06 mg/L).复合吸附剂对Pb2+的吸附总量正比于pH(1.5～5)和温度(303～323 K).在研究纳米复合材料对铅离子的吸附动力学实验中发现,纳米复合材料和铅离子之间的吸附动力学符合假二级模型,通过相关热力学研究计算得到纳米材料和铅离子之间为吸热反应.
文摘The electrochemical behavior of Mn (Ⅲ)/Mn(Ⅱ)ion-pair on platinum electrode in acid media were studied by cyclic voltammetry.It was demonstrated that the redox process of Mn(Ⅲ)/Mn(Ⅱ) pair was a simple pseudo-reversible one-electron reaction between Mn(Ⅲ) and Mn(Ⅱ).The electrochemical kinetics of the redox reaction on static Pt electrode was a mass transfer controlled one.The calculated diffusion coefficient of Mn(Ⅱ) was 1.48×10 -6cm 2/s.
