重金属锑污染土壤固化-稳定化修复技术研究及应用

固化-稳定化技术具有快速、经济、有效等优点,在重金属污染土壤修复中得到了广泛应用,然而对重金属修复药剂选型及现场实际应用研究仍存在不足。本文首先利用小试实验探究了不同修复药剂对重金属锑的修复效果,筛选出适用药剂及配比,并通过上海某重金属锑污染修复工程的具体实施,总结出一套重金属污染土壤固化-稳定化施工工艺流程,为重金属锑固化-稳定化修复技术的发展及应用提供理论指导和经验借鉴。

污泥原位固化-稳定化处理中试研究

为了探讨固化-稳定化技术的可行性以及后续环境安全问题,对污泥堆置场进行了原位固化处理试验。经过试验和监测分析表明:使用原位固化-稳定化处理工艺可以有效地进行原位处理,处理后经过一个星期污泥强度达到100 kPa以上,含水率小于50%,重金属的浸出量达到GB 8978—2002《污水综合排放标准》的要求。如将原位处理后的场地作为一个污泥单独填埋场封场或污染场地修复的角度进行评估,原位固化-稳定化处理能够满足相关技术指标的要求。

钻井废弃物高强度固化处理新技术

为消除钻井废弃物的环境影响并赋予其较高资源化利用潜力,采用改性氯氧镁水泥,对钻井废弃物进行高强度固化处理,优化固化体系各组成比例,用X射线衍射(XRD)和扫描电子显微镜(SEM)分析固化产物组成及微观结构,并评价其浸出毒性。结果表明:固化钻井废弃物原料组成对其抗压强度有较大影响,最优比例的固化体系,经过压实成型,环境温度下养护,其14 d抗压强度最高可达38 MPa;胶结材料水化产物中大量的5Mg(OH)2.MgCl2.8H2O使固化试样产生较大的抗压强度,粉煤灰活性组分反应产物提高了固化物的性能,这是晶体共生产生的机械嵌合作用和独特的空间网状结构的结果;固化物浸出毒性符合国家环境标准要求;处理后的钻井废弃物具有较高的抗压强度和环境相容性,处理工业废弃物量高达65.7%。

Theoretical Aspects on Doped-Zirconia for Solid Oxide Fuel Cells:from Structure to Conductivity

Solid oxide fuel cells(SOFCs)are regarded to be a key clean energy system to convert chemical energy(e.g.H_(2) and O_(2))into electrical energy with high efficiency,low carbon footprint,and fuel flexibility.The electrolyte,typically doped zirconia,is the"state of the heart"of the fuel cell technologies,determining the performance and the operating temperature of the overall cells.Yttria stabilized zirconia(YSZ)have been widely used in SOFC due to its excellent oxide ion conductivity at high temperature.The composition and temperature dependence of the conductivity has been hotly studied in experiment and,more recently,by theoretical simulations.The characterization of the atomic structure for the mixed oxide system with different compositions is the key for elucidating the conductivity behavior,which,however,is of great challenge to both experiment and theory.This review presents recent theoretical progress on the structure and conductivity of YSZ electrolyte.We compare different theoretical methods and their results,outlining the merits and deficiencies of the methods.We highlight the recent results achieved by using stochastic surface walking global optimization with global neural network potential(SSW-NN)method,which appear to agree with available experimental data.The advent of machine-learning atomic simulation provides an affordable,efficient and accurate way to understand the complex material phenomena as encountered in solid electrolyte.The future research directions for design better electrolytes are also discussed.

H_2O/CO_2 co-electrolysis in solid oxide electrolysis cells

A solid oxide electrolysis cell(SOEC) is an environmental-friendly device which can convert electric energy into chemical energy with high efficiency. In this paper,the progress on structure and operational principle of an SOEC for co-electrolyzing H2O and CO2to generate syngas was reviewed. The recent development of high temperature H2O/CO2co-electrolysis from solid oxide single electrolysis cell was introduced. Also investigated was H2O/CO2co-electrolysis research using hydrogen electrode-supported nickel(Ni)-yttria-stabilized zirconia(YSZ)/YSZ/Sr-doped LaMnO3(LSM)-YSZ cells in our group. With 50 % H2O,15.6 % H2and 34.4 % CO2inlet gas to Ni- YSZ electrode,polarization curves(I- U curves) and electrochemical impedance spectra(EIS) were measured at 800 ℃ and 900 ℃. Long-term durability of electrolysis was carried out with the same inlet gas at 900 ℃ and 0.2 A/cm2. In addition,the improvement of structure and development of novel materials for increasing the electrolysis efficiency of SOECs were put forward as well.

城市污泥中重金属去除技术研究

重金属污染是目前城市污水处理厂污泥农用的主要障碍之一。综述了城市污泥中重金属去除的常用四种技术：化学浸提、生物淋滤、动电技术和固化-稳定化,同时分析了污泥中重金属去除技术的发展方向。

Effect of sulfate erosion on strength and leaching characteristic of stabilized heavy metal contaminated red clay

Solidification/stabilization(S/S)technology has been widely used for remediation of the heavy metal contaminated soils.The heavy metal ions will be leached from the stabilized contaminated soil under sulfate erosion conditions,which gives rise tosecondary contamination to the areas around the mine sites.The commonly used Portland cement,fly ash and quicklime were takenas binder raw materials with various mix proportions.And then,the sulphuric acid and nitric acid method was used to investigate theleaching characteristic of stabilized heavy metal contaminated soils.The effects of binder types and binder contents,sulfateconcentrations(1.5,3.0and6.0g/L)and erosion time(0,7,14and28d)on leached concentrations of heavy metal ions fromcontaminated soils were studied.Moreover,a parameter named immobilization percentage(IP)was introduced to evaluate theinfluence of erosion time and sulfate concentration on immobilization effectiveness for heavy metal ions.The results showed that,theleached heavy metal concentrations increased with sulfate concentration and erosion time.Comparatively speaking,the compositebinders that had calcium oxide in it exhibited the worst solidification effectiveness and the lowest immobilization percentage,withthe largest leached heavy metal concentration.

Fuel Cell Technology for Propulsion and Power Generation of Ships： Feasibility Study on Ocean Research Vessel Sagarnidhi

Rising fuel prices, increasing emission levels and impending environmental regulations made shipping industry to find an alternate for internal combustion engine in 21st century. Fuel cell is a sustainable, emerging technology with negligible pollution. More significantly for a research ship, emission levels need to be substantially low to have quality measurements. A feasibility study is carried-out First time in the world, to drive an ice class multi-disciplinary ORV （Oceanography Research Vessel） Sagarnidbi, using hydrogen powered fuel cell. Sagamidhi is equipped with special equipments viz., Deep Sea winch, specially designed cranes for Launching and retrieval of ROV （Remotely Operable Vehicle）, DSMC （Deep Sea Mining Crawler）, Tsunami systems, manned/unmanned submersible and ACS （Autonomous Coring System） and other facilities that support research in Indian, International and Antarctic waters. Beside this, the propulsion system along with DP （Dynamic Positioning）, centralized air conditioning and special equipments require enormous electrical power. The combustion of diesel oil in an engine, that coupled with an alternator generates electrical power required, along with NOx （Nitrous Oxides）, SOx （Sulphur Oxides） and PM （Particulate Matter） emissions. Shipping industry is the fourth largest contributor to air pollution and carbon emissions, particularly in coastal areas, and the growth rate makes the problem even more critical. Stringent international air pollution regulation and increasing fuel price paves the way for an alternative ＂green emission technology＂. Various fuel cells were analyzed with different combination of fuel, electrolyte and electrodes. From the analysis, it has been found that SOFC （Solid Oxide Fuel Cell） is most suitable for the present scenario. A fuel cell designed with hydrogen as fuel, zirconium oxides stabilized with yttrium oxide as electrolyte and zirconium electrodes is used for 1.5 MW power output and 0.5 MW through regenerator. Volume required for storage of hydrogen is in line with volume of fuel and a high standard safety measures were taken using sensors. The present system saves 3000 MT/annum of diesel oil costing 3,000,000 USD approximately.

Selective Adsorption Properties and Stable Solidification of Cs by Insoluble Ferrocyanide Loaded Zeolites

In Fukushima NPP-1, large amounts of HALW （high-activity-level water） accumulated in the reactor, turbine building and the trench in the facility is treated by circulating injection cooling system. The development of highly functional adsorbents and stable solidification method contributes to the advancement of the decontamination system and environmental remediation. The present study deals with： （1） preparation of insoluble ferrocyanide loaded zeolites; （2） selective uptake of Cs~ in seawater; and （3） estimation of Cs immobilization ratio and stable solidification. Various kinds of Cs-selective composites loaded with insoluble ferrocyanides （CoFC, NiFC） into the zeolites （zeolite A （A51, A-51J）, zeolite X （LSX）, chabazite （modified chabazite） and natural mordenite （SA-5）） matrices have been prepared to use successive impregnation/precipitation methods by Tohoku University. As for Cs~ adsorption, these composites had relatively large uptake （%） over 95%, distribution coefficients （Kd） above 103 cm3/g and excellent adsorption kinetics even in seawater. The immobilization ratio （%） of Cs for the CoFC saturated with Cs＋was estimated at different calcination temperatures up to 1,200 ℃ in advance. The immobilization ratio was less than 0.1% above 1,000℃, indicating that the adsorbed Cs~ ions are completely volatilized and insoluble ferrocyanides had no immobilization ability for Cs. In contrast, the insoluble ferrocyanide-loaded zeolites had excellent Cs immobilization ability; in the case of insoluble ferrocyanide-loaded natural zeolites （NiFC-SA-5, CoFC-modified chabazite）, the immobilization ratio was above 99% and 96% even after calcination at 1,000 ℃ and 1,100 ℃, respectively, indicating that nearly all Cs ions are immobilized in the sintered solid form. On the other hand, the immobilization ratio for the insoluble ferrocyanide-loaded A and X zeolites （NiFC-A （A51, A51J）, NiFC-X） tended to decrease with calcining temperature; for example, the immobilization ratio for NiFC-X at 1,000 ℃and 1,100 ℃ was estimated to be 74.9% and 55.4%, respectively, and many spots concentrating Cs were observed on the surface. The difference in immobilization behavior between natural zeolites and synthetic ones is probably due to the phase transformation and surface morphology at higher temperature above 1,000 ℃. The stable solidification of insoluble ferrocyanides was thus accomplished by using the excellent Cs immobilization abilities of zeolite matrices （Cs trapping and self-sintering abilities）.

The preparation of supported ionic liquids (SILs) and their application in rare metals separation

This review summarizes the preparation methods of support ionic liquids （SILs） and their applications in rare metals separation The rare metals separation includes the recovery of high value metal ions and the removal of heavy metal ions from wastewater. SILs can be used as a kind of highly efficient multifunctional separation materials. The preparation methods of SILs include chemical immobilization technique in which ILs moieties are supported on solid supports via covalent bonds and physical immobilization techniques in which ILs are immobilized on solid supports via physical method such as simple im- pregnation, sol-gel method. According to the difference of solid supports, this review summarizes the application of polymer supported ionic liquids （P-SILs）, silica based material supported ionic liquids （SM-SILs） and membrane supported ionic liq- uids （M-SILs） in rare metals separation, P-SILs and SM-SILs prepared by chemical method with N-methylimidazolium group can be used as highly efficient anion exchangers with high thermal stability and good chemical stability for adsorption of Cr（Ⅵ）, Re（Ⅶ）, Ce（Ⅳ）. P-SILs prepared via simple impregnation afforded IL functionalized solvent impregnated resins （SIRs） which showed high separation efficiency and selectivity in the separation of rare earths（Ⅲ） （REs（Ⅲ））. SM-SILs prepared via sol-gel method with IL doped in the support as porogens or extractant show high removal efficiencies and excellent stability for the separation of RE（Ⅲ）, Cr（Ⅲ） and Cr（Ⅵ）. M-SILs with IL as plasticizer or carrier show improved stability, high perme- ability coefficient and good selectivity for Cr（VI） transport. Different supports and different supporting methods were suffi- ciently compared. Based on the different practical application, different forms of SILs can be prepared for separation of rare metals with high separation efficiency and selectivity.