磷酸银/树脂复合物的制备及其对亚甲基蓝的光催化降解

以聚乙烯吡咯烷酮(PVP)为稳定剂,采用化学沉积法制备了磷酸银/树脂复合物,降解亚甲基蓝,研究其光催化活性,并对样品进行了XRD和SEM表征。探讨了不同的光源、催化剂投加量、PVP含量、p H值等因素对亚甲基蓝降解率的影响。结果表明,在太阳光(夏天早上9点到11点的阳光)下,偏酸介质中,催化剂用量为0.8 g/L,PVP质量分数为0.01%的磷酸银/树脂复合物,液面高度为15 cm的条件下对亚甲基蓝有最佳降解效果。     

新型纳米结构铈锰复合氧化物的磷吸附行为与机制研究

采用共沉淀法制备了一种新型铈锰复合氧化物吸附剂,对其进行了表征,并对磷吸附行为与机制进行了研究.表征结果分析表明,此氧化物由纳米级颗粒组成;铈锰复合氧化物中的铈氧化物有类似水合氧化铈的无定形结构;BET比表面积为157 m2·g-1,等电点为6.5.吸附实验结果表明,Langmuir吸附等温线模型可以更好地拟合铈锰复合氧化物对磷的吸附,最大吸附量为28.6 mg·g-1(p H=7.0);铈锰复合氧化物对磷具有较高的吸附速率,更符合准二级动力学模型;溶液p H对铈锰复合氧化物吸附磷的影响较为明显,随p H升高,吸附量降低;离子强度则影响不大;共存阴离子对吸附影响的大小顺序为Si O2-3CO2-3Cl-≥SO2-4.通过对铈锰复合氧化物吸附磷前后Zeta电位和红外谱图(FTIR)分析,可以推断磷在铈锰复合氧化物表面发生了特性吸附,磷酸根主要通过取代复合氧化物表面的金属羟基而被吸附去除.     

Effect of commercial pesticides on plant growth-promoting activities of Burkholderia sp. strain L2 isolated from rhizosphere of Lycopersicon esculentum cultivated in agricultural soil

The in vitro study was carried out to examine the toxicity of four commercially used pesticides (phorate, mancozeb, chlorpyrifos, and endosulfan) at the recommended dose (1X) and higher field doses (1.5X, 2X, 2.5X, and 3X) on plant growth-promoting activities of Burkholderia sp. strain L2, isolated from pesticide-treated rhizosphere of Lycopersicon esculentum. At the recommended dose, level of toxicity of all the pesticides to phosphate solubilization activity and indole-3-acetic acid (IAA) production was less detrimental as compared to exceeding doses. At maximum dose rate of each pesticide, the percentage decrease in phosphate solubilization and IAA production over control was found in order of chlorpyrifos < mancozeb < endosulfan < phorate. Present study proves that Burkholderia sp. strain L2 could be used as a potential microbial inoculant in the agricultural soil having persistent pesticide residues.     

水环境中不同形态氮对甲芬那酸光降解影响机制的研究

研究了紫外光照射下水环境中不同形态的无机氮(NO-3、NO-2和NH+4)对甲芬那酸(MEF)光解的影响.NO-3与NO-2均促进MEF的光解,NH+4对MEF的光解基本无影响;在NO-3、NO-2存在下添加适量异丙醇,显著抑制MEF的降解,实验表明NO-3、NO-2在光照下产生了·OH并参与对MEF的氧化降解.同时模拟研究了水体处于不同p E值下,水中存在的不同形态的无机氮对MEF光解的复合影响,其对MEF光解促进作用不是简单的叠加关系,增大p E值,MEF的光解速率先增大后减小.当NO-2和NH+4共存时,对MEF的光解主要表现为NO-2的影响;当NO-2和NO-3共存时,两者对MEF的光解存在拮抗作用.     

Growth and alkaline phosphatase activity of Chattonella marina and Heterosigma akashiwo in response to phosphorus limitation

The growth and alkaline phosphatase activity (APA) of two raphidophyceae species Chattonella marina and Heterosigma akashiwo were investigated in response to P-limitation and subsequent addition of dissolved inorganic phosphorus (DIP, NaH₂PO₄) and two dissolved organic phosphorus (DOP) compounds: guanosine 5-monophosphate (GMP) and triethyl phosphate (TEP). APAlevels increased greatly after P-starvation as the decrease of the cellular phosphorus quotes (Q_p). C. marina responded to P-limitation quickly and strongly, with 10-fold increase in APA within 24 hr after P-starvation. The larger difference between maximal and minimal Q_p values in C. marina indicated its high capacity in P storage. APA of H. akashiwo wasmaximally enlarged about 2.5 times at 48 hr of P-starvation. After the addition of nutrients, cell numbers of C. marina increased in all treatments including the P-free culture, demonstrating the higher endurance of C. marina to P-limitation. However, those of H. akashiwo increased only in DIP and GMP cultures. APA increased only after the addition of the monophosphate ester GMP. The results suggest that quick responses of C. marina to P-limitation, high capacity in P storage as well as endurance for P-depletion provide this species an ecological advantage in phytoplankton community competition under DIP-limited conditions.     

Enhanced CO2 adsorptive performance of PEI/SBA-15 adsorbent using phosphate ester based surfactants as additives

In this study,a series of polyetherimide/SBA-15: 2-D hexagonal P6 mm,Santa Barbara USA(PEI/SBA-15) adsorbents modified by phosphoric ester based surfactants(including tri(2-ethylhexyl)phosphate(TEP),bis(2-ethylhexyl) phosphate(BEP) and trimethyl phosphonoacetate(TMPA))were prepared for CO_2 adsorption.Experimental results indicated that the addition of TEP and BEP had positive effects on CO_2 adsorption capacity over PEI/SBA-15.In particular,the CO_2 adsorption amount could be improved by around 20% for 45PEI–5TEP/SBA-15 compared to the additive-free adsorbent.This could be attributed to the decrease of CO_2 diffusion resistance in the PEI bulk network due to the interactions between TEP and loaded PEI molecules,which was further confirmed by adsorption kinetics results.In addition,it was also found that the cyclic performance of the TEP-modified adsorbent was better than the surfactant-free one.This could be due to two main reasons,based on the results of in situ DRIFT and TG-DSC tests.First and more importantly,adsorbed CO_2 species could be desorbed more rapidly over TEP-modified adsorbent during the thermal desorption process.Furthermore,the enhanced thermal stability after TEP addition ensured lower degradation of amine groups during adsorption/desorption cycles.     

共存阴阳离子对针铁矿表面磷固存机制的影响研究

磷素(P)兼具重要养分元素的利和潜在面源污染的弊,其在土壤环境中的固存行为及其迁移转化过程受到广泛关注.该研究选取黄、红壤中典型矿物(针铁矿、赤铁矿及高岭石)为模式矿物,在排除pH干扰的条件下,开展了共存阴(As(V))阳(Cd(II))离子对矿物表面P(V)固存机制的影响研究.结果表明:P(V)在不同矿物表面的吸附效...     

The integrated project AquaTerra of the EU sixth framework lays foundations for better understanding of river-sediment-soil-groundwater systems

The integrated project "AquaTerra" with the full title "integrated modeling of the river-sediment-soil-groundwater system; advanced tools for the management of catchment areas and river basins in the context of global change" is among the first environmental projects within the sixth Framework Program of the European Union. Commencing in June 2004, it brought together a multidisciplinary team of 45 partner organizations from 12 EU countries, Romania, Switzerland, Serbia and Montenegro. AquaTerra is an ambitious project with the primary objective of laying the foundations for a better understanding of the behavior of environmental pollutants and their fluxes in the soil-sediment-water system with respect to climate and land use changes. The project performs research as well as modeling on river-sediment-soil-groundwater systems through quantification of deposition, sorption and turnover rates and the development of numerical models to reveal fluxes and trends in soil and sediment functioning. Scales ranging from the laboratory to river basins are addressed with the potential to provide improved river basin management, enhanced soil and groundwater monitoring as well as the early identification and forecasting of impacts on water quantity and quality. Study areas are the catchments of the Ebro, Meuse, Elbe and Danube Rivers and the Brévilles Spring. Here we outline the general structure of the project and the activities conducted within eleven existing sub-projects of AquaTerra.     

酸/碱改性香蒲生物炭对水中磷的去除及其机制研究

雨水径流中存在的磷污染问题严重威胁生态环境,而传统的雨水径流处理设施,如雨水花园、渗滤沟等,对磷的去除率较低且成本较高.以湿地中收割的香蒲为原材料,酸改性后制备的生物炭（TH7）的除磷效果非常好,明显优于碱改性生物炭（TOH7）：与原生物炭（T7）相比,酸改性生物炭大大提高了磷的去除效率,可从T7的65%提高至94%,而碱改性生物炭无除磷效果.TH7的表面孔隙发达,比表面积高达434.2m²·g^-1,对磷的吸附符合Freundlich模型和伪二级动力学模型,其吸附属于物理化学吸附,具体的机制为孔隙填充、表面化学沉淀、氢键结合.研究表明,以香蒲为原料制备的改性生物炭是一种效果优越的除磷吸附剂,可应用于植草沟、雨水花园等以填料为主要吸附层的径流处理设施中.     

不同磁黄铁矿自养反硝化脱氮除磷作用

氮磷排放标准日趋严格,开发高效廉价脱氮除磷材料已成为研究热点.采用黄铁矿与赤铁矿在管式炉中氮气气氛下600 ℃煅烧,得到硫化赤铁矿形成的磁黄铁矿、黄铁矿热分解形成的磁黄铁矿,构建磁黄铁矿-方解石体系处理含氮磷模拟废水,对比不同方式制备的磁黄铁矿、天然磁黄铁矿、黄铁矿、硫磺脱氮除磷性能,考察不同磁黄铁矿晶体结构和结晶度差异及其对脱氮除磷影响,探究不同体系中矿物结构和微生物群落变化.结果表明：黄铁矿热分解产物以六方磁黄铁矿为主;硫化赤铁矿产物以低结晶度的单斜磁黄铁矿为主,因而表现出优异的脱氮除磷活性,氮磷去除率分别为99.8%和96.8%.铁硫化物与微生物反应产物的XRD、SEM和FE-TEM分析结果表明,微生物能有效利用磁黄铁矿进行脱氮,磷酸盐主要以FePO₄形式被去除.群落分析结果表明铁硫化物脱氮除磷体系中的主要功能菌属为Thiobacillus和 Sulfurimonas,结晶度低的单斜磁黄铁矿更有利于Thiobacillus定向富集.