选择性萃取方法在生物膜上铁、锰氧化物分离中的应用

1　IntroductionSurfacecoatings (biofilmsandassociatedminerals)existonallkindsofsolidphasesinnaturalaquaticenvironments.FeandMnoxideswerefoundedtobethemostimportantcomponentsofsur facecoatingsfortheirhighadsorptioncapacity[1—3].Tostudytherelativeroleofdif…     

铜锰钴复合氧化物催化剂对环己烷或苯深度氧化的催化活性

本文应用了研究相图与床层温差评价催化活性的方法，研究了在催化深度氧化环己烷或苯的反应中，铜、锰、钴三元氧化物催化剂体系的组成与催化活性的关系。用反应物在催化剂上起燃温度的等温图，描绘出该体系氧化物催化剂对环己烷或苯的催化氧化活性的分布。所得结果指导了用于净化苯系物废气所需催化剂的研制。     

Citrate-promoted dissolution of nanostructured manganese oxides: Implications for nano-enabled sustainable agriculture

Nanostructured manganese oxides (nano-MnO_x) have shown great promises as versatile agrochemicals in nano-enabled sustainable agriculture, owing to the coupled benefits of controlled release of dissolved Mn²⁺, an essential nutrient needed by plants, and oxidative destruction of environmental organic pollutants. Here, we show that three δ-MnO₂ nanomaterials consisting of nanosheet-assembled flower-like nanospheres not only exhibit greater kinetics in citrate-promoted dissolution, but also are less prone to passivation, compared with three α-MnO₂ nanowire materials. The better performance of the δ-MnO₂ nanomaterials can be attributed to their higher abundance of surface unsaturated Mn atoms–particularly Mn(III)–that is originated from their specific exposed facets and higher abundance of surface defects sites. Our results underline the great potential of modulating nanomaterial surface atomic configuration to improve their performance in sustainable agricultural applications.     

单种及混合培养条件下Fe、Mn对赤潮生物塔玛亚历山大藻(Alexandriumtamarense)生长的影响

研究了单种和两种混合世量培养条件下，Ｆｅ－ＥＤＴＡ（Ｆｅ＾３＋）、Ｍｎ（Ｍｎ＾２＋）浓度对甲藻塔玛亚历山大藻（Ａｌｅｘａｎｄｒｉｕｍ ｔａｍａｒｅｎｓｅ）生长及细胞大小的影响。同时考察了与其混合培养中的肋骨条藻（Ｓｋｅｌｅｔｏｎｅｍａ ｃｏｓｔａｔｕｍ）和圆筛藻（Ｃｏｓｃｉｍｏｄｉｓ ｃｕｓ ｓｐ．）的生长特性，结果表明在本实验的浓度范围内（Ｆｅ－ＥＤＴＡ，０－３．１５μｇ／Ｌ，Ｍｎ＾２＋，０－０     

Simultaneous oxidation of Mn(II) and As(III) on cupric oxide (CuO) promotes As(III) removal at circumneutral pH

Oxidation of Mn(II) or As(III) by molecular oxygen is slow at pH < 9, while they can be catalytically oxidized in the presence of oxide minerals and then removed from contaminated water. However, the reaction mechanisms on simultaneous oxidation of Mn(II) and As(III) on oxide mineral surface and their accompanied removal efficiency remain unclear. This study compared Mn(II) oxidation on four common metal oxides (γ-Al₂O₃, CuO, α-Fe₂O₃ and ZnO) and investigated the simultaneous oxidation and removal of Mn(II) and As(III) through batch experiments and spectroscopic analyses. Among the tested oxides, CuO and α-Fe₂O₃ possess greater catalytic activity toward Mn(II) oxidation. Oxidation and removal kinetics of Mn(II) and As(III) on CuO indicate that O₂ is the terminal electron acceptor for Mn(II) and As(III) oxidation on CuO, and Mn(II) acts as an electron shuttle to promote As(III) oxidation and removal. The main oxidized product of Mn(II) on CuO is high-valent MnO_x species. This newly formed Mn(III) or Mn(IV) phases promote As(III) oxidation on CuO at circumneutral pH 8 and is reduced to Mn(II), which may be then released into solution. This study provides new insights into metal oxide-catalyzed oxidation of pollutants Mn(II) and As(III) and suggests that CuO should be considered as an efficient material to remediate Mn(II) and As(III) contamination.     

Photochemically enhanced degradation of phenol using heterogeneous Fenton-type catalysts

The degradation of phenol was carriced out using heterogeneous Fenton-type catalysts in the presence of H2O2 and UV.Catalysts were prepared by exchanging and immobilizing Fe^2 in zeolite 13X,silica gel or Al2O3.The concentration of phenol solution was 100mg/L.The amount of H2O2 added was the stoichiometric amount of H2O2 required for the total oxidation of phenol.Under the irradiation of medium pressure light(300W)phenol was mineralized within 1 h in the presence of Fe^2 /zeolite 13X.The COD removal rate was enhanced in the presence of Fe^2 /zeolite 13X compared to that of Fe^2 /silica gel of Fe^2 /Al2O3.Analogous homogenous photo-Fenton reaction with equivalent Fe^2 was also carried out to evaluate the catalysis efficiency of Fe^2 /zeolite 13X.Results showed that the COD removal rate was near to that of homogeneous Fenton,while heterogeneous Fe^2 /zeolite 13X catalyst coule be recycled.     

印染废水治理技术

论述了以铁碳过滤 +SBR为主要工艺的印染废水处理技术。该技术在实际工程中连续运行 8a的结果表明 :该工艺用于印染废水的治理切实可行、经济可靠 ,出水水质稳定能够达到国家一级排放标准 ,并能全部实现回用     

无机阴离子对Fe-TiO2/SiO2复合光催化剂脱色染料的影响

考察了6种常见的无机阴离子对金属掺杂Fe-TiO2／SiO2复合光催化剂光催化降解酸性红B反应的影响，考察了导致催化剂失活的无机阴离子的最低浓度．结果发现H2PO4^-、HCO3^-具有较强的抑制作用，SO4^3-、I^-具有一定的抑制作用，而NO3^-、CI^-无明显影响实验结果证实无机离子对金属掺杂Fe-TiO2／SiO2活性的影响比TiO2／SiO2催化剂的影响明显要弱．对催化剂失活的机制也作了探讨。     

DNAPL remediation with in situ chemical oxidation using potassium permanganate. II. Increasing removal efficiency by dissolving Mn oxide precipitates

In situ chemical oxidation (ISCO) schemes using MnO4- have been effective in destroying chlorinated organic solvents dissolved in ground water. Laboratory experiments and field pilot tests reveal that the precipitation of Mn oxide, one of the reaction products, causes a reduction of permeability, which can lead to flow bypassing and inefficiency of the scheme. Without a solution to this problem of plugging, it is difficult to remove DNAPL from the subsurface completely. In a companion paper, we showed with batch experiments that Mn oxide can be dissolved rapidly with certain organic acids. This study utilizes 2-D flow-tank experiments to examine the possibility of nearly complete DNAPL removal by ISCO with MnO4-, when organic acids are used to remove Mn oxide. The experiments were conducted in a small 2-D glass flow tank containing a lenticular silica-sand medium. Blue-dyed trichloroethylene (TCE) provided residual, the perched and pooled DNAPL. KMnO4 at 200 mg/l was flushed through the DNAPL horizontally. Once plugging reduced permeability and prevented further delivery of the oxidant, citric or oxalic acids were pumped into the flow tank to dissolve the Mn oxide precipitates. Organic ligands removed the Mn oxide precipitates relatively quickly, and permitted another cycle of MnO4- flooding. Cycles of MnO4-/acid flooding continued until all of the visible DNAPL was removed. The experiments were monitored with chemical analysis and visualization. A mass-balance calculation indicated that by the end of the experiments, all the DNAPL was removed. The results show also how heterogeneity adds complexity to initial redistribution of DNAPL, and to the efficiency of the chemical flooding.     

磁流体处理印染废水初探

探讨了Fe3O4磁流体在不同条件下对降低印染废水的COD和色度两个方面的影响，实验表明，当pH=11，十二烷基叔胺的量是亚铁量的0．16倍时，COD降低最多，脱色效果最好，且磁场强度在160mT左右时，磁流体沉降最快。