Photodegradation of Dyes in Aqueous Solutions containing Fe(III) -hydroxy Complex II. Solar Photodegradation Kinetics

The solar photodegradation of five dyes, C.I. reactive red 2, C.I. reactive blue 4, C.I. reactive black 8, C.I. basic red 13, and C.I. basic yellow 2, were studied in a sunlight/Fe(III)-hydroxy system. It was observed that the photodegradation of these five dyes were pseudo-first order reactions, which has a little difference with the photodegradation kinetics of the dyes with UV-light as the irradiation source. The comparison between the two studies is also conducted.     

铁碳微电解法处理某化工厂废水的研究

某化工厂废水主要成份为乙醛、少量三聚乙醛、四聚乙醛、吡啶和一些乙醛聚合物。经吸附塔处理后出水ρ(CODCr)值在3000￣4000mg·L-1之间,BOD5/CODCr只有0.05,采用铁碳微电解方法进行预处理。实验结果表明,最合适反应条件是进水pH值为2、铁碳比1∶2、停留时间为2h,在此条件下CODCr去除率可达64%以上,且进水浓度的变化对去除率影响不大。而且,BOD5/CODCr值在0.45以上,提高了可生化性。     

三价铁促进生物氧化锰稳定土壤砷的效果和机制

通过室内模拟实验,研究了三价铁对生物氧化锰（BMO）稳定化砷污染土壤的促进效果与作用机制.实验结果表明：三价铁的添加提高了BMO对土壤中砷的稳定化效率,当三价铁以质量分数百分比（以Fe计）为0.5%、1%、2%和4%添加时,砷的稳定化效率由单独BMO处理的63.02%增加至86.04%、93.86%、96.56%和97.98%;由连续提取实验结果可知,添加三价铁能够促进土壤中砷的结合形态由可交换态、专属吸附态向无定型铁锰结合态和结晶型铁锰结合态转变,增强土壤中砷的稳定化作用;风险分析进一步表明添加三价铁后砷的环境风险由中风险转变为低风险;矿物晶体结构分析表明,添加三价铁后土壤中出现水铁矿、纤铁矿等次生铁氧化物,这些铁氧化物对土壤中砷有良好的吸附固定能力.总体而言,三价铁的存在能够提高BMO对砷污染土壤的稳定化效率,但三价铁的添加量不宜过高,否则会引起土壤酸化问题.     

金属有机骨架材料MIL-101用于气态碘单质的吸附与释放

目的研究金属有机骨架材料MIL-101对气态碘单质的吸附与释放。方法采用水热合成法合成金属有机骨架材料MIL-101,并利用X射线衍射(XRD)、扫描电子显微镜(SEM)、N2吸附脱附等温线等表征方法对合成的MIL-101样品进行表征。将制备的金属有机骨架材料MIL-101在75℃环境下对气态碘单质进行吸附,将吸附后的材料于无水乙醇溶液中进行碘单质的释放。结果随着吸附时间的推移,金属有机骨架材料MIL-101对气态碘单质的吸附量逐渐升高,并于8 h逐渐达到饱和吸附量2.61 g(I2)/g(MIL-101)。MIL-101在无水乙醇溶液中随着时间的延长,材料吸附的碘单质渐渐释放出来。结论 MIL-101对气态碘单质在较高温度下有着优异的吸附效果,并表现出良好的循环使用性能,适合用于核电站蒸汽中放射性气态碘的吸附。     

Fe~(3+)/TiO_2负载膨胀珍珠岩降解水和土壤中苯酚的研究

以膨胀珍珠岩(EP)作为载体,采用溶胶凝胶法对其进行Ti O_2、Fe3+-Ti O_2溶胶负载,制备出Ti O_2、Fe3+-Ti O_2表面修饰的膨胀珍珠岩材料(TEP、FTEP),通过SEM、TEM、XRD和FI-IR对其进行表征,实验室条件下模拟研究了EP、TEP、FTEP对水和土壤中苯酚的吸附降解效果。结果表明,450℃光催化材料为锐钛矿型,Fe3+掺杂有效提高了光催化性。本实验条件中,当达到最佳投加量时,水和土壤中的EP、FTEP、TEP对苯酚的降解率分别为23.40%、100%、100%和17.81%、66.75%、69.01%;在最适光照时间下,水和土壤中的EP、FTEP、TEP对苯酚的降解率依次为22.14%、100%、100%和17.64%、66.15%、67.51%。在实验浓度范围内,该光催化反应符合一级反应动力学方程。     

高铁酸盐(Fe(Ⅵ))氧化去除水中PPCPs的研究进展

药物和个人护理用品(PPCPs)采用传统的污水处理方法不易去除,高铁酸盐(Fe(VI))因具有强氧化性,且氧化产物Fe(III)具有絮凝作用,近年来被广泛应用于去除PPCPs。介绍了Fe(VI)近年来的制备进展,分析了Fe(VI)去除PPCPs的效率及影响因素,探讨了Fe(VI)与PPCPs的反应机理及产物、中间产物的毒性变化,并展望了未来Fe(VI)去除PPCPs的研究方向。Fe(VI)能有效去除多种PPCPs,去除效率受p H值、温度、Fe(VI)初始浓度和PPCPs性质影响,Fe(VI)与PPCPs反应的中间产物毒性值得关注。     

Nickel recovery from electronic waste II Electrodeposition of Ni and Ni–Fe alloys from diluted sulfate solutions

This study focuses on the electrodeposition of Ni and Ni–Fe alloys from synthetic solutions similar to those obtained by the dissolution of electron gun (an electrical component of cathode ray tubes) waste. The influence of various parameters (pH, electrolyte composition, Ni²⁺/Fe²⁺ ratio, current density) on the electrodeposition process was investigated. Scanning electron microscopy (SEM) and X-ray fluorescence analysis (XRFA) were used to provide information about the obtained deposits’ thickness, morphology, and elemental composition. By controlling the experimental parameters, the composition of the Ni–Fe alloys can be tailored towards specific applications. Complementarily, the differences in the nucleation mechanisms for Ni, Fe and Ni–Fe deposition from sulfate solutions have been evaluated and discussed using cyclic voltammetry and potential step chronoamperometry. The obtained results suggest a progressive nucleation mechanism for Ni, while for Fe and Ni–Fe, the obtained data points are best fitted to an instantaneous nucleation model.     

Effects of wastewater discharge on formation of Fe plaque on root surface and radial oxygen loss of mangrove roots

Effects of wastewater discharge on radial oxygen loss (ROL), formation of iron (Fe) plaque on root surface, and their correlations in Bruguiera gymnorrhiza (L.) Poir and Excoecaria agallocha L. were investigated. ROL along a lateral root increased more rapidly in control than that in strong wastewater (with pollutant concentrations ten times of that in municipal sewage, 10NW) treatment, but less Fe plaque was formed in control for both plants. For B. gymnorrhiza receiving 10NW, Fe plaque formation was more at basal and mature zones than at root tip, while opposite trend was shown in E. agallocha. At day 0, the correlation between ROL and Fe plaque was insignificant, but negative and positive correlations were found in 10NW and control, respectively, at day 105, suggesting that more ROL was induced leading to more Fe plaque. However, excess Fe plaque also served as a ‘barrier’ to prevent excessive ROL in 10NW plants.     

烟气脱硫石膏催化还原为硫化钙的研究

采用Fe-Ni复合催化剂,在温度650℃条件下即可将烟气脱硫石膏催化还原为硫化钙,还原率达95%以上。研究了反应温度、催化剂加入量及还原气体含量因素对还原反应的影响。     

聚合硅酸铝铁絮凝剂中铁的形态分布与转化

以AlCl₃·6H₂O ,FeCl₃·6H₂O ,Na₂CO₃,盐酸和硅酸钠为原料制备了不同碱化度B及不同n(Al)∶n(Fe)∶n(Si)摩尔比的系列聚合硅酸铝铁絮凝剂 (PAFSC) ,采用Fe -Ferron逐时络合比色法研究了PAFSC中铁的形态分布情况 ,考察了熟化时间、制备工艺及n(Al)∶n(Fe)∶n(Si)对PAFSC中铁的形态分布的影响情况。研究结果表明 :随着熟化时间的延长 ,铁和聚硅酸摩尔数的增加 ,PAFSC中铁的形态由低聚物向高聚物转化.