Fe_3O_4@SiO_2复合气凝胶的制备及其对刚果红的吸附

以Fe Cl_3·6H_2O和正硅酸四乙酯为原料,通过溶胶-凝胶法结合醇溶剂热法制备了Fe_3O_4@Si O_2复合气凝胶。采用XRD,FTIR,SEM,EDS等技术对Fe_3O_4@Si O_2的结构进行了表征。考察了Fe_3O_4@Si O_2对刚果红溶液的吸附性能。表征结果显示,Fe_3O_4@Si O_2复合气凝胶是由直径为10~20 nm的近球形颗粒组装而成的具有三维网络结构的纳米材料,比表面积为457.93 m~2/g,平均孔径为10.7 nm。在溶液p H为5、吸附时间为35 min的最佳工艺条件下,采用Fe_3O_4@Si O_2吸附处理质量浓度为10 mg/L的刚果红溶液,刚果红去除率为99.39%,此时溶液中刚果红的质量浓度仅为0.052 mg/L。Fe_3O_4@Si O_2复合气凝胶吸附刚果红后具有较好的解吸和再生能力。     

Visible light induces bacteria to produce superoxide for manganese oxidation

● Term of manganese-oxidizing microorganisms should be reconsidered. ● Visible light induces heterotrophic bacteria to produce superoxide. ● Heterotrophic bacteria oxidize Mn(II) ions with a fast oxidation rate. ● Superoxide oxidizing Mn(II) ions is an unintended side reaction of bacteria. ● Superoxide is an important oxidation force of Mn(II) in the environment. Manganese oxides are widely distributed in soils and sediments, affecting the migration and transformation of heavy metals and organic pollutants. The microbial conversion of soluble Mn(II) into insoluble Mn(III/IV) oxides is considered to be the initial source of manganese oxides in the environment; however, whether this process is related to a physiological role remains unclear. Here, we explored the microbial manganese oxidation process under visible light by using coastal surface seawater microorganisms. Visible light greatly promotes the oxidation rate of Mn(II), and the average rate reaches 64 μmol/(L·d). The generated manganese oxides were then conducive to Mn(II) oxidation, thus the rapid manganese oxidation was the result of the combined action of biotic and abiotic, and biological function accounts for 88 % ± 4 %. Extracellular superoxide produced by microorganisms induced by visible light is the decisive factor for the rapid manganese oxidation in our study. But the production of these superoxides does not require the presence of Mn(II) ions, the Mn(II) oxidation process was more like an unintentional side reaction, which did not affect the growth of microorganisms. More than 70 % of heterotrophic microorganisms in nature are capable of producing superoxide, based on the oxidizing properties of free radicals, all these bacteria can participate in the geochemical cycle of manganese. What’s more, the superoxide oxidation pathway might be a significant natural source of manganese oxide.     

自来水厂除锰滤砂的催化活性分析

研究来自我国东北２个自来水厂的除锰滤砂对Ｍｎ＾２＋的催化活性,以确定微生物在除锰过程中的作用,利用ＰＹＣＭ培养基可在每ｇ湿砂上计到１０＾５－１０＾６个细菌,其中有４０％￣５０％具有Ｍｎ＾２＋氧化能力,对滤砂表面的微生物进行原位培养,灭菌和ＨｇＣｌ２抑制,表明微生物群落的存在与稳定对于活性表面的存在与稳定是至关重要的,当生物活性被抑制后,锰砂残余活性约为原活性的２０％,这部分活性可能来源于化学催化。     

基于吡啶甲基萘酰亚胺的水中痕量铁检测方法研究

合成了一种新型的荧光分子探针N-(2-吡啶甲基)-1,8-萘酰亚胺(PMN),研究了其在环境水样中痕量铁离子的检测应用.结果表明,该方法选择性好,灵敏度高,操作简便,且常见金属离子不干扰测定.Fe3+浓度在1×10-7~8×10-5mol/L范围内,荧光强度与其浓度呈良好的线性关系.方法用于自来水、井水、生活污水中痕量铁的测定,回收率在95.78%~104.02 %之间.     

高岭土界面Fe(Ⅱ)吸附与邻硝基苯酚还原转化的交互反应研究

研究了高岭土界面亚铁吸附与邻硝基苯酚(2-nitrophenol,2-NP)还原转化的交互作用.考察了反应pH值、界面吸附铁密度、反应温度(T)对2-NP的还原动力学的影响.结果表明,吸附态Fe(Ⅱ)为2-NP还原转化的关键物种,高龄土界面Fe(Ⅱ)吸附能明显提高还原反应的反应速率.2-NP的还原转化速率常数(k)随着反应pH值的升高、吸附铁密度的增加、反应温度的升高而增大,ln k与pH、吸附铁密度、1/T都具有明显的线性关系.2-NP还原转化的活化能为87.15 kJ·mol-1,吸附反应的活化能为18.5 kJ·mol-1.该研究可为土壤矿物界面物理化学与氧化还原的交互反应过程研究提供借鉴.     

自来水厂细菌固定化除锰及其水质条件的研究

对自来水厂除锰细菌的３种固定化途径进行了实验分析。表明生态平衡的自固定化能够在短期内高效、稳定地除锰,通过控制运行参数和水质,把滤柱的除锰成熟期期短为５０ｄ。。     

火焰原子吸收光谱法测定苏州开发区26种蔬菜中铜锌铁锰镍

用火焰原子吸收光谱法测定了苏州开发区26种蔬菜中的铜、锌、铁、锰和镍的含量。蔬菜样品用硝酸高氯酸混合酸进行消解。4次测定值的相对标准差<5%,加标回收率在92%～107%之间。26种蔬菜中铜、锌、铁、锰、镍的含量基本均在世贸组织规定的范围内。     

纳米Pd/Fe双金属对2,4-二氯酚的脱氯机理及动力学

采用纳米Pd Fe双金属对2,4 二氯酚(2,4 DCP)进行了催化还原脱氯处理.结果表明,纳米Pd Fe双金属具有较高的比表面积和反应活性,对2,4 DCP具有较好的脱氯效率.当纳米Pd Fe用量在6g·L-1时,2,4 DCP脱氯率达到90%以上;脱氯效率与pH值、温度、钯化率、Pd Fe投加量等因素有关.2,4 DCP在脱氯过程中先生成邻氯酚和对氯酚,而后继续脱氯生成苯酚,或由2,4 DCP直接降解成苯酚.2,4 DCP降解符合拟一级反应动力学.2,4 DCP催化还原脱氯反应的活化能为139 7kJ·mol-1.     

Equilibrium,kinetics and thermodynamics studies on adsorptive removal of cobalt ions from wastewater using MIL-100(Fe)

This study describes experiments in which MIL-100(Fe) was used to remove Co²⁺ ions from the waste water. The synthesised adsorbent was characterised by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction, Brunauer–Emmett–Teller (BET) and scanning electron microscope. Statistical analysis was used to investigate the effects of different parameters. From the obtained results, the removal efficiency was enhanced with increasing contact time and pH but decreased with increasing cobalt initial concentration. The maximum removal efficiency of Co⁺² was 93.4% under optimum conditions. The equilibrium adsorption data were best fitted to linearly transformed Freundlich isotherm. Adsorption kinetic data followed the pseudo second-order kinetic model. The maximum adsorption capacity of Co⁺² on to the MIL-100(Fe) was found to be 119 mg g^?1. The results showed that ?G of adsorption was negative, while ?H was positive which showed that the adsorption process was spontaneous and endothermic. The positive value of ?S showed that disordering and randomness increased at the solid–solution interface of cobalt ions with MIL-100(Fe) particles.     

Fe3O4-PTFE电极制备条件和双阴极电-Fenton反应条件的优化

制备了Fe₃O₄-聚四氟乙烯（PTFE）电极,优化了原料配比和焙烧温度。对比了Fe₃O₄-PTFE单阴极和Fe₃O₄-PTFE与乙炔碳黑-PTFE电极并联双阴极体系对模拟Rhb染料废水的处理效果。实验结果表明：在m（Fe₃O₄）∶m（PTFE）=3.0∶2.5、焙烧温度为300 ℃的条件下制备Fe₃O₄-PTFE电极,采用阴极电-Fenton法降解模拟Rhb废水的效果最佳,电解反应120 min时Rhb降解率达86.91%;Fe₃O₄-PTFE电极与乙炔碳黑-PTFE电极并联作为双阴极电解Rhb废水时,最佳电压为6 V,最佳初始废水pH为3,在此条件下电解反应120 min时Rhb降解率达91.65%。