煤基腐殖酸对外源砷胁迫下玉米生长及生理性状的影响简

为了筛选用于砷污染土壤治理的煤基腐殖酸,采用盆栽实验研究了施用不同种类和浓度的煤基腐殖酸及EDTA对外源砷胁迫下玉米株高、株鲜重、株干重、根干重、砷积累量、叶片抗氧化酶（POD,SOD和CAT）活性和脯氨酸含量的影响。结果表明,11种供试煤基腐殖酸均促进了玉米生长,提高了叶片POD、SOD和CAT活性。其中6和10号腐殖酸可降低土壤砷活性和显著抑制玉米吸收和积累砷,而8和9号腐殖酸增加了土壤活性砷和显著促进了玉米对砷的吸收和累积,且不同程度地强于EDTA。除8和9号外,其余腐殖酸均可明显降低玉米叶片脯氨酸的含量。EDTA可显著促进玉米吸收和积累砷,且加剧了砷对玉米的危害。因此,8和9号供试煤基腐殖酸可以替代EDTA活化土壤砷,与植物配合以提高砷污染土壤的植物修复速度和效果,而6和10号供试煤基腐殖酸则可用于土壤砷钝化剂,以保证作物产品的安全。     

工业废水中多金属离子的吸附净化

以含有Si、Al、Ca、C元素的矿物材料作为基质,经特定条件处理后造粒成型加工成轻质多孔Si-Al-Ca-C结构的吸附材料。研究了该吸附材料对工业废水中多种金属离子的吸附性能,探讨了影响吸附性能的因素。研究结果表明,在一定条件下,Si-Al-Ca-C吸附材料对工业废水中Al3+、Ca2+、Mn2+、Cu2+、Fe3+、Mg2+、As3+和Zn2+的净化率分别高达99.34%、99.82%、98.26%、98.16%、97.76%、97.01%、100%和89.09%。金属离子残留浓度分别为0.152、0.07、0.012、0.02、0.119、0.311、0和0.259 mg/L,均低于国家污水综合排放标准(GB8978-1996)一级标准。     

Photodegradation mechanism of two dyes: the influence of adsorption behavior on the novel TiO2 particles

The relationship between adsorption behavior and photocatalytic mechanism of the two dyes was investigated. Adsorption isotherms showed that the adsorption of cationic pink FG was Langmuir type behavior, while the reactive brilliant red k-2G was Freundlich type behavior. The increasing pH favored the adsorption of FG but have little effect on the photodegradation. The increasing pH favored the adsorption and the photodegradation of k-2G. The presence of scavenger of hvb^ and OH. radical potassium iodide inhibited the degradation of k-2G, free radicals scavenger tetranitromethane inhibited the photodegradation of FG. These results indicated that the photodegradation of FG mainly via free radicals in solution, and the photodegradation of k-2G was mainly on the catalysts surface or near the interface of solid and solution by react with hvb^ and surface-bound OH.. The different effect of SO4^2- , HCO3^- on the adsorption and photodegradation of two dyes confirmed these results.     

Decrease of NH4+-N by bacterioplankton accelerated the removal of cyanobacterial blooms in aerated aquatic ecosystem

We used aerated systems to assess the influence of the bacterioplankton community on cyanobacterial blooms in algae/post-bloom of Lake Taihu, China. Bacterioplankton community diversity was evaluated by polymerase chain reaction-denaturing gradient gel electrophoresis(PCR-DGGE) fingerprinting. Chemical analysis and nitrogen dynamic changes illustrated that NH4+-N was nitrified to NO2-N and NO3-N by bacterioplankton. Finally, NH4+-N was exhausted and NO3-N was denitrified to NO2-N, while the accumulation of NO2-N indicated that bacterioplankton with completely aerobic denitrification ability were lacking in the water samples collected from Lake Taihu. We suggested that adding completely aerobic denitrification bacteria(to denitrify NO2-N to N2)would improve the water quality. PCR-DGGE and sequencing results showed that more than 1/3 of the bacterial species were associated with the removal of nitrogen, and Acidovorax temperans was the dominant one. PCR-DGGE, variation of nitrogen, removal efciencies of chlorophyll-a and canonical correspondence analysis indicated that the bacterioplankton significantly influenced the physiological and biochemical changes of cyanobacteria. Additionally, the unweighted pair-group method with arithmetic means revealed there was no obvious harm to the microecosystem from aeration. The present study demonstrated that bacterioplankton can play crucial roles in aerated ecosystems, which could control the impact of cyanobacterial blooms in eutrophicated fresh water systems.     

硼泥吸附水中酚的研究

经加热活化处理的硼泥,用于处理50mg/L的含酚废水,加入量为1％时,最佳吸附酚的pH为2～4,去除率为32％;加入量为5％时,去除率最好可达60％。吸附平衡浓度与吸附量关系符合Lanmuir吸附等温式,其20.0、25.0、30.0℃时的饱和吸附量分别为3.25、2.50、1.75mg/g,其吸附速度符合鲛岛吸附动力学方程。通过活性硼泥的红外光谱和Ｘ射线衍射图,探讨了吸附机理。     

我国东部冲积平原区水成土壤元素背景值地域分异规律

从气候条件、母质物质组成的差异以及河流上下游物质之间的联系等角度，讨论了我国东部冲积平原区土壤中１３种元素的地理分布趋势及影响因素。研究表明，大多数元素具有明显的南北向地域分布趋势，这种趋势是地带性和非地带性因素共同决定的，而以非地带因素更重要。此外，东部平原土壤与相应主要河流上游侵蚀区土壤微量元素含量具有很好的共轭关系。     

磷酸铵镁沉淀法预处理垃圾渗滤液

探讨了用磷酸铵镁沉淀法预处理垃圾渗滤液时,沉淀剂种类、pH值、物质摩尔配比和反应时间等因素对氨氮去除效果的影响。得出了处理氨氮浓度为2 677.34 mg/L的垃圾渗滤液时,在兼顾所用镁盐量尽量低和处理出水氨氮或磷酸盐的残留量都比较低的较佳实验条件为:沉淀剂种类为:MgSO4.7H2O和Na2HPO4.12H2O,反应时间为20 min,pH=9.5,n(Mg)∶n(P)∶n(N)=1.3∶1.15∶1.0。在较佳实验条件下,垃圾渗滤液的NH3-N去除率为97.05%,处理出水PO34--P含量为8.35 mg/L,NH3-N含量为75.86 mg/L。对所得沉淀物进行了成分分析和X-衍射光谱、扫描电镜表征,表明大部分沉淀物为磷酸铵镁物质。     

吹扫捕集气质联用测定水中嗅味物质的研究

文章建立了一种用吹扫捕集—气相色谱质谱联用技术测定饮用水中土臭素(GSM)和二甲基异冰片(2-MIB)等嗅味物质的分析方法,确定了最佳的色谱条件、质谱条件和水样处理方法。当取样量为25mL时,回收率分别为96%和89%,RSD<10%,检出限为0.002mg/L。     

喜凉作物生长期对全球变暖停滞响应的时空差异——以中国绿洲为例

基于中国绿洲喜凉作物（chimonophilous crop）分布区39个站点1960~2016年逐日平均气温资料,运用线性趋势法、反距离加权插值（IDW）、Morlet小波、Mann-Kendall检验等方法,研究中国绿洲喜凉作物气候生长期的时空变化对变暖停滞的响应.结果表明：①变暖停滞期,中国绿洲喜凉作物气候生长期起、止日及生长期日数以-0.2d/10a、0.33d/10a、0.53d/10a的趋势变化,较1960~2016年起始日提前趋势减缓1.01d/10a,终止日推迟减缓1.28d/10a,生长期日数延长减缓2.3d/10a,对变暖停滞有响应.②中国绿洲喜凉作物气候生长期起始日对变暖停滞响应的站点有44%,终止日和生长期日数均为49%,主要分布在南疆、柴达木盆地和河西绿洲,其中河西绿洲对变暖停滞响应最明显,南疆次之,柴达木最小,而北疆绿洲不存在滞缓现象,显然空间差异明显.③M-K检验显示,中国绿洲喜凉作物气候生长期起、止日及生长期日数分别在2001年、1990年和1997年发生突变,起始日晚于变暖停滞起始年份,终止日和生长期日数早于变暖停滞起始年,且分绿洲生长期日数突变年与变暖停滞起始年相接近.④Morlet小波得出变暖停滞期其变化稳定存在2.4~4.3a的震荡周期,表明未来几年中国绿洲喜凉作物气候生长期仍持续延长.     

The role of doped-Mn on enhancing arsenic removal by MgAl-LDHs

To meet the challenges posed by global arsenic water contamination, the MgAlMn-LDHs with extraordinary efficiency of arsenate removal was developed. In order to clarify the enhancement effect of the doped-Mn on the arsenate removal performance of the LDHs, the cluster models of the MgAlMn-LDHs and MgAl-LDHs were established and calculated by using density functional theory (DFT). The results shown that the doped-Mn can significantly change the electronic structure of the LDHs and improve its chemical activity. Compared with the MgAl-LDHs that without the doped-Mn, the HOMO-LUMO gap was smaller after doping. In addition, the -OH and Al on the laminates were also activated to improve the adsorption property of the LDHs. Besides, the doped-Mn existed as a novel active site. On the other hand, the MgAlMn-LDHs with the doped-Mn, the increased of the binding energy, as well as the decreased of the ion exchange energy of interlayer Cl⁻, making the ability to arsenate removal had been considerably elevated than the MgAl-LDHs. Furthermore, there is an obvious coordination covalent bond between arsenate and the laminates of the MgAlMn-LDHs that with the doped-Mn.