Influence of root-exudates concentration on pyrene degradation and soil microbial characteristics in pyrene contaminated soil

The effect of ryegrass (Lolium perenne L.) root-exudates concentration on pyrene degradation and the microbial ecological characteristics in the pyrene contaminated soil was investigated by simulating a gradually reducing concentration of root exudates with the distance away from root surface in the rhizosphere. Results showed that, after the root-exudates were added 15 d, the pyrene residue in contaminated soil responded nonlinearly in the soils with the same pyrene contaminated level as the added root-exudates concentration increased, which decreased first and increased latter with the increase of the added root-exudates concentration. The lowest pyrene concentration appeared when the root exudates concentration of 32.75 mg kg(-1) total organic carbon (TOC) was added. At the same time, changes of microbial biomass carbon (MBC, C(mic)) and microbial quotient (C(mic)/C(org)) were opposite to the trend of pyrene degradation as the added root-exudates concentration increased. Phospholipid fatty acid (PLFA) analysis revealed that bacteria was the dominating microbial community in pyrene contaminated soil, and the changing trends of pyrene degradation and bacteria number were the same. The changing trend of endoenzyme-dehydrogenase activity was in accordance with that of soil microbe, indicating which could reflect the quantitative characteristic of detoxification to pyrene by soil microbe. The changes in the soils microbial community and corresponding microbial biochemistry characteristics were the ecological mechanism influencing pyrene degradation with increasing concentration of the added root-exudates in the pyrene contaminated soil.     

Comparison of homologous and heterologous formats in nanocolloidal gold-based immunoassays for parathion residue determination

The effectiveness of homologous and heterologous formats in a nanocolloidal gold-based immunoassay for pesticide residue determination was investigated. Parathion, one of the most toxic organophosphorus pesticides, was used as the target analyte. One-step homologous and heterologous test strips based on a nanocolloidal gold-labeled monoclonal antibody were developed for the rapid detection of parathion residues. The results showed that the heterologous format was more effective than the homologous format, being more sensitive, more specific to parathion and more tolerant of matrix interferences. The best competitive hapten was found to have a moderate heterology and the opposite electronic distribution to the immunizing hapten. The detection limits for parathion using the preferred heterologous strip were 1 μg/L in water samples and 5 μg/kg in soil and food samples.     

植物对潜流人工湿地净化微污染水效果的影响研究

以4种湿地植物为实验对象,在野外构建中试潜流人工湿地,研究了不同植物及植物连根收割对湿地运行效果的影响。结果显示,植物明显提升了湿地的去污效果;其中美人蕉湿地的TP和NH4+-N去除率最高,达到55.6%和78%;空心菜湿地的TN去除率最高,达到80.5%;芦竹湿地的COD去除率最高,为26.6%;植物连根收割后,湿地运行效果下降;其中TN去除率降至空白水平之下,而其他污染指标下降至略高于空白的水平。     

玉米深加工废水的混凝实验

在室温条件下,分别选用聚合氯化铝(PAC)、聚合氯化铝铁(PAFC)及三氯化铁(FeCl3)对玉米深加工废水进行混凝实验。综合考虑各种混凝剂对磷、COD以及SS的去除效果,最终选取PAC作为混凝剂。采用PAC和聚丙烯酰胺(PAM)作为复合混凝剂,对其去除效果做进一步研究,并确定了最佳投加量及pH值。实验结果表明,在PAC投加量25mg/L,PAM投加量0.5 mg/L,pH为8条件下,混凝效果最佳。磷、COD、SS去除率可分别达到90.1%、53.3%和88.2%,对应的出水质量浓度分别为0.41、26.8和2 mg/L。     

林可霉素菌(Streptomyces lincolnensis)利用吡唑酮废水的研究

采用被吡唑酮废液驯化、分离、筛选后的林可霉素菌,并对其在摇瓶上利用吡唑酮废液中的硫酸铵发酵(7 d)生产林可霉素进行了研究。实验结果表明,废液加入培养基体积比都为1∶10,实验1中菌丝代谢和对照比正常,其中还原糖利用最快,在发酵后期为0.24 mg/L,林可霉素起步效价最低为2 100 IU/mL,与对照相比最后发酵效价降低了70 IU/mL;实验2发酵过程pH值偏低,全程为5.86～6.50,氨基氮代谢缓慢为40 mg/100 mL,最后林可霉素效价最低为4 480 IU/mL;实验3中废液在发酵进入48 h中后期的时候补入能促进菌丝体分泌,最后林可霉素为5 180 IU/mL,比对照发酵水平高出8.82%。可见实验3的实验设计有利于林可霉素菌利用吡唑酮废液生产林可霉素,为废物循环利用、变废为宝的可行性作了有意义尝试。     

模拟阳光下Ag／I-TiO2光催化预处理山核桃加工废水

研究了在模拟太阳光下,采用银修饰的碘掺杂二氧化钛光催化剂（Ag／I—TiO2）对某食品厂山核桃加工废水进行光催化预处理的效果。结合x射线衍射（XRD）、比表面积分析（BET）、紫外-可见漫反射光谱（uV—Vis）的表征结果,来分析催化剂结构对于废水处理效果的影响。探讨了Ag含量、废水初始pH（pHi）和光照时间等因素对化学需氧量（COD）去除及水质可生化性（B／C）提高的影响。并得出适宜的反应参数为：3％Ag含量;pHi为6;光照时间为240min。在最佳条件下,COD去除率45％,废水B／C比由0．17上升到0．31。光催化氧化法能够有效降低山核桃加工废水的COD含量,并达到显著提高废水可生化性的目的。     

A/O+MBR工艺处理玉米深加工废水的中试研究

实验基于企业污水站的改造工程,研究了MBR对玉米深加工废水的处理效果并对工艺运行参数优化提出建议.结果表明,该工艺对COD的去除率可以达到90％以上,出水稳定在26 mg/L左右;出水NH4-N达到1 mg/L以下;TN去除率达到70％以上,出水TN达到10 mg/L以下,出水完全达到排放标准.通过4种工况的比较,说明在污泥浓度8 g/L左右,曝气池内DO在3 mg/L左右,MBR内DO＞4 mg/L,好氧段停留时间13.5 h,并保证3h以上的缺氧段水力停留段时间的条件下,A/O+ MBR工艺可以有效去除玉米深加工废水中的污染物.     

电吸附对水中盐类、氨氮、COD的去除效果分析

电吸附技术作为高效、环境友好型的除盐、除氨氮技术,可应用与水的深度处理领域内。为了使污水回用达到工业用水的水质标准,对电吸附去除水中盐类、氨氮、COD的效果进行分析,结果表明,电吸附设备处理不同氨氮浓度的废水,对中低浓度的氨氮去除效果稳定,当进水氨氮浓度低于20 mg/L时,处理后出水氨氮浓度低于5 mg/L,COD浓度小于25 mg/L,达到回用标准;随着进水盐浓度的增大电吸附处理效果逐渐变差,在电导率低于2 500 μS/cm时除盐率在75%左右,氨氮去除率达到70%左右,COD去除率达到60%左右。经电吸附处理后的低氨氮浓度废水,TDS、氨氮浓度均可达到工业回用水标准。     

改性SiO2气凝胶对废水中Fe3+的吸附性能

制备了改性SiO₂气凝胶,考察了经不同类型、不同配比的改性剂改性的SiO₂气凝胶对模拟含Fe³⁺废水的吸附处理效果。实验结果表明：改性SiO₂气凝胶的最佳制备条件为三甲基氯硅烷（TMCS）作改性剂,V（TMCS）#x02236;V（正己烷）=1#x02236;5;当改性SiO₂气凝胶加入量为75g/L、吸附时间为4h、Fe³⁺质量浓度为10mg/L时,模拟含Fe³⁺废水的Fe³⁺去除率为98.32%,剩余Fe³⁺质量浓度为0.168mg/L;采用改性SiO₂气凝胶动态吸附处理流量为420mL/h、Fe³⁺质量浓度为100mg/L的模拟含Fe³⁺废水,吸附后废水中剩余Fe³⁺质量浓度仅为0.196mg/L。     

An overview on the processes and technologies for recycling cathodic active materials from spent lithium-ion batteries

This paper aims to make an overview on the current status and new tendency for recycling cathodic active materials from spent lithium-ion batteries. Firstly, it introduces several kinds of pretreatment technologies, followed by the summary of all kinds of single recycling processes mainly focusing on organic acid leaching and synergistic extraction. Then, several examples of typical combined processes and industrial recycling processes are presented in detail. Meanwhile, the advantages, disadvantages and prospect of each single process, combined process, as well as industrial recycling processes, are discussed. Finally, based on a novel acidic organic solvent, the authors briefly introduce an environmental friendly process to directly recycle and resynthesize cathodic active material LiNi_1/3Co_1/3Mn_1/3O₂ from spent lithium-ion batteries. The preliminary experimental results demonstrated the advantages of low reaction temperature, high separation efficiency and organic solvent cycling and preventing secondary pollution to the environment. This process may be used for large-scale recycling of spent lithium-ion batteries after further study.