纳米FeO作用下4-氯酚的脱氯特性及机理

采用化学还原法制备了纳米Fe^O, ESEM测定结果表明其颗粒在1～100 nm内. 实验表明这些纳米Fe^O能在20 h内将初始浓度为20 mg/L的4-氯酚完全降解, Fe^O对4-CP的还原脱氯是主要去除途径. 苯酚是脱氯反应的主要产物. 当4-CP的初始浓度由20　mg/L增大到50, 100, 150　mg/L时, 其相对去除率明显降低, 但绝对降解量有较大提高. 温度不仅影响脱氯速率, 而且影响4-CP去除的途径. 30℃时, 脱氯反应为主要反应; １０℃时, 较易产生氧化产物. Fe原子的迁移过程在4-CP的降解中也是一个重要的限速步骤. 此外, 纳米Fe^O具有很好的稳定性, 在受试的379　h内, 纳米Fe^O能够应对不同浓度冲击及反复投加的4-氯酚冲击的能力.     

高铁低铝煤矸石酸法提取铝、铁研究

以高铁低铝煤矸石为原料,经机械活化,酸浸提取有价元素铝、铁.首先利用硫酸盐在不同温度和不同硫酸质量分数条件下的溶解度差异,通过结晶分离法从酸浸液中转移出硫酸盐,然后利用新鲜煤矸石中和酸浸液中的游离酸,调节pH值至1.5～2.0,制备酸浸初步净化液.以初步净化液为研究对象,利用不同离子水解pH值的差异进行物质分离,再经纯化处理制备相应产品.用XRD对原料和产品进行了表征.结果表明,在硫酸质量分数为75％的条件下,反应液固比为4、温度为125℃、3h时煤矸石中铝、铁溶出率分别为92.5％、99.7％.通过项目经济效益分析可知,该法可以产生良好的环境效益、社会效益,同时可实现煤矸石增值,产生较好的经济效益.     

烧结烟气中氨-络合法同步脱硫脱硝络合剂再生的实验研究

对氨-络合法同步脱硫脱硝废液中络合剂再生进行了实验研究。结果表明,在50℃、p H值为5.65、Fe(Ⅱ)-EDTA浓度为0.04 mol/L、再生剂/Fe(Ⅱ)EDTA为2∶1的条件下,经铁粉再生后吸收液最高脱硫脱硝效率分别达到99%和75%;焦粉再生最高脱硫脱硝效率达到97%和46%;而乙二醛再生最高脱硫脱硝效率仅为80%和20%。同时铁粉再生中试结果也还表明脱硫效果可以稳定在100%,脱硝效果可维持在60%。     

钢铁企业大气污染环保提升技术措施

针对2015年1月1日新《中华人民共和国环境保护法》和钢铁排放系列新标准(2012版)实施的新形势,指出了钢铁企业面临的五大考验,分析了大气污染物治理的技术现状,提出实现钢铁工业大气污染环保提升的技术措施。     

Interaction between Cu2+ and different types of surface-modified nanoscale zero-valent iron during their transport in porous media

This study investigated the interaction between Cu²⁺ and nano zero-valent iron (NZVI) coated with three types of stabilizers (i.e., polyacrylic acid [PAA], Tween-20 and starch) by examining the Cu²⁺ uptake, colloidal stability and mobility of surface-modified NZVI (SM-NZVI) in the presence of Cu²⁺. The uptake of Cu²⁺ by SM-NZVI and the colloidal stability of the Cu-bearing SM-NZVI were examined in batch tests. The results showed that NZVI coated with different modifiers exhibited different affinities for Cu²⁺, which resulted in varying colloidal stability of different SM-NZVI in the presence of Cu²⁺. The presence of Cu²⁺ exerted a slight influence on the aggregation and settling of NZVI modified with PAA or Tween-20. However, the presence of Cu²⁺ caused significant aggregation and sedimentation of starch-modified NZVI, which is due to Cu²⁺ complexation with the starch molecules coated on the surface of the particles. Column experiments were conducted to investigate the co-transport of Cu²⁺ in association with SM-NZVI in water-saturated quartz sand. It was presumed that a physical straining mechanism accounted for the retention of Cu-bearing SM-NZVI in the porous media. Moreover, the enhanced aggregation of SM-NZVI in the presence of Cu²⁺ may be contributing to this straining effect.     

Fe~0-厌氧微生物降解2,4-二氯酚的效应及机理

以2,4-二氯酚(2,4-DCP)为目标污染物,采用间歇试验,接种厌氧混合微生物,考察葡萄糖共基质条件下不同pH值时零价铁(Fe)0对2,4-DCP生物降解的效应,并对Fe0与厌氧微生物联合体系的作用机理进行探讨。结果表明:Fe0与厌氧微生物联合作用可提高2,4-DCP的降解效果,且中性或偏碱性环境下联合体系对目标污染物的促进效果较酸性环境明显,初始pH值为8时目标污染物的降解效果最好。Fe0在厌氧条件下腐蚀产生的OH-可有效平衡葡萄糖发酵产生的有机酸,使体系挥发性脂肪酸(VFA)的浓度维持在较低水平(300 mg/L),同时促使联合体系pH值上升从而利于目标物2,4-DCP的降解。Fe0在酸性环境的腐蚀较强,腐蚀产物以Fe2+为主,Fe3+含量较少。不同pH值时"Fe0+微生物"体系的COD去除率与目标物降解效果有一定相关性。     

北京市密云水库上游金铁矿区土壤重金属污染特征及对比研究

不同金属矿山选冶活动造成的矿区及周边土壤中重金属的分布累积特征不同.为了解密云水库上游金矿和铁矿矿区土壤中重金属地球化学特征的异同及污染状况,对区域内典型的金矿和铁矿矿区进行土壤样品采集,应用地球化学方法研究了2种土壤中重金属的污染特征,并应用地累积指数法评价了其污染状况.结果表明,2种土壤中除As外的其它重金属含量明显高于北京市土壤重金属背景值,金矿矿区土壤重金属含量普遍高于铁矿矿区.相关性分析表明,金矿矿区土壤中Cu含量与Pb、Zn(p<0.01)及Cr、有机质(OM)含量(p<0.05)之间显著相关,pH值与Pb含量(p<0.01)及Hg含量(p<0.05)呈显著负相关,而铁矿矿区土壤中重金属含量之间的相关性不显著.金矿尾砂中重金属含量明显高于铁矿尾砂,与矿区土壤污染状况一致.地累积指数法评价结果显示,金铁矿区土壤中重金属的污染程度均已十分严重,金矿矿区土壤污染程度高于铁矿,金矿矿区土壤重金属的污染程度由高到低依次为:Pb>Hg>Cd>Cr>Cu>Zn>Co>As;铁矿矿区土壤重金属的污染程度由高到低依次为:Pb>Cd>Cr>Co>Cu>Zn>Hg>As.该研究数据可为同一区域内不同金属矿区重金属污染的有效监控与治理提供科学依据.     

Dynamics of arsenic in salt marsh sediments from Dongtan wetland of the Yangtze River estuary, China

The mobility and transformation of arsenic (As) in salt marsh sediments were investigated in Dongtan wetland of the Yangtze River estuary, China. As in surface water, pore water and the rhizosphere sediments were quantified. The microcosm incubation experiments were conducted during the flooding of the sediments to examine As dynamics that occurred during changing redox conditions. The concentrations of dissolved As in pore water (0.04-0.95 μmol/L) were significantly greater than that in surface water (0.03-0.06 μmol/L). Under anoxic conditions, the reactive As could be initially mobilized by the reductive dissolution of Fe(III) (hydr)oxides. Subsequently, most of the dissolved As was likely to be associated with secondary iron (hydr)oxide phases and remained in solid phases. The seasonal variability of acid volatile sulfide concentrations suggest the anoxic conditions are enhanced during summer by Spartina alterniflora compared to Phragmites australis and Scirpus mariqueter, causing a notable increase in As mobility. Generally, there was a typical variation in redox conditions with season in salt marsh sediments of Dongtan wetland, in which the dynamics of As mobility and transformation possibly were controlled by iron, and all of this could be significantly influenced by the rapid spread of S. alterniflora.     

水合氧化铁对含磷废水的吸附特性研究

以Fe(NO3)3为前驱物,制备了水合氧化铁吸附剂样品,以NaOH为解吸剂,研究了样品对模拟废水中磷酸根的吸附和解吸性能。结果表明,水合氧化铁对磷酸根有较好的吸附效果;随着pH的降低,水合氧化铁对磷酸根的吸附能力增强,在pH为2时吸附达92.5%;吸附前15 min吸附速率较快,约150 min达到平衡,吸附动力学曲线符合二级动力学模型;用水合氧化铁对初始浓度为50~100 mg/L模拟含磷废水吸附,随着初始浓度的增大,磷的去除率下降;水合氧化铁对磷酸根的吸附等温线较符合Langmuir吸附模型;用NaOH对水合氧化铁行解吸,浓度为40 g/L有最好的解吸率,60 min时达到解吸平衡。     

矸石电厂粉煤灰制备微晶玻璃预提取铁、铝的研究

通过试验,就矸石电厂粉煤灰提取铁、铝并将二者有效分离的方法进行了探讨;结合后续制备微晶玻璃的工艺,提出了相关的技术要求,以保证整个研究的经济性和完整性.研究结果表明：二次沉淀法有效地实现了铁、铝分离,为微晶玻璃的制备创造了条件,且工艺简单,控制点少,可操作性强.