动态浸出模拟实验系统与静态浸出试验的对比

建立了动态浸出试验－－小柱模拟实验系统,研究在非饱和水条件下危险物质在填埋场中的迁移和浸出规律,并和静肪浸出实验进行比较,结果表明,在非饱和入渗条件下危险物质的浸出浓度要比静态浸出实验的结果小１００倍左右,危险发的浸出速率也远小于静实验的结果,同时,危险物质的浸出速率随废物层饮水度的增加而迅速增加。     

磷酸二氢钙和氯化钾对乌栅土氮素淋失的影响

利用土柱淋洗,研究了N、P、K共施对太湖乌栅土氮素(Urea-N、NH₄⁺-N和NO₃^--N)淋失的影响.结果表明,在不施尿素的条件下,N的淋失以NO₃^--N为主,占淋失总氮(Urea-N、NH₄⁺-N和NO₃^--N之和)的93.39%.施加尿素后,Urea-N、NH₄⁺-N和NO₃^--N的淋失量明显增加,三者占淋失N的比例分别为3.95%、15.25%和80.80%,占施入N的比例分别为0.26%、0.80%和2.54%.Ca(H₂PO₄)₂或KCl均可显著增加3种形态N的淋失,使3种形态N占淋失TN的比例分别为4.54%、24.11%、71.35%和3.45%、24.53%、72.02%,占施入N的比例分别为0.39%、1.86%、3.34%和0.32%、2.12%、4.06%.Ca(H2PO4)2和KCl共施对N素淋失存在着一定的交互作用,使3种形态N占淋失TN的比例分别达到4.10%、27.35%和68.55%,占施入N的比例分别为0.42%、2.60%和4.26%.不同形态N淋失的先后顺序为:Urea-N >NH₄⁺-N>NO₃^--N,而淋失总量的顺序为:Urea-N < NH₄⁺3^--N.     

废弃液晶显示器中铟的溴化法浸出研究

液晶显示器(LCD)是电视、电脑和手机等电子产品的重要部件,资源化回收所含的稀有金属铟具有重要意义。结果表明:(1)采用溴化法浸出LCD中的铟,在采用Br2、溴化钠及硫酸质量浓度分别为20、16、55.2g/L的溴水浸出剂、浸出时间3h、温度50℃的条件下,铟浸出率可达99.2%。(2)采用双极室阴离子膜电解槽电解回收Br2,当电解电压为1.8V、电解时间为300min时,采用四氯化碳对浸出液中未参加反应的Br2进行萃取回收,Br2的回收率为83.5%;电解阴极液中的Fe3+被还原为Fe2+以达到屏蔽目的,电解240min后Fe2+生成量达1 801mg/L,转化率为90.9%。(3)采用氢氧化钠沉淀法粗提取铟,当pH为4.78时,沉淀物的主要成分为In(OH)3,滤渣中In3+占总金属离子质量的47.9%,铟的回收率为94.8%。     

不同浸提剂对污染河道底泥中重金属的浸出影响

以某有色金属冶炼企业排放口下游河道底泥为研究对象,分别采用无机酸(盐酸、硫酸、硝酸)和有机酸(醋酸、柠檬酸、苹果酸和丁二酸)研究在不同酸性条件(pH为2~6)下Pb、Cd、Zn、Cu的浸出效果。结果表明,有机酸的浸提能力明显高于无机酸,且4种重金属的浸出浓度均随着pH的升高而迅速降低。对无机酸而言,当pH3时,重金属的浸出浓度趋于稳定;对有机酸而言,在pH为2~5的较大范围内,醋酸表现出较高的浸提能力,而柠檬酸对Pb和Cu没有明显的浸出效果。结合泥质特点,从重金属的络合、沉淀、水解、吸附等反应过程对其浸出特征进行了分析,同时提出醋酸良好的缓冲能力是其浸提效果优于其他有机酸的重要原因。     

酸浸出法回收冶金污泥中的有价金属

采用二次酸浸出的方法回收镍钴湿法冶金工业污泥中的有价金属。先采用水和硫酸作为浸出剂浸出Mg和Na,最佳工艺条件为浸出液的pH 7.5、浸出时间5 min、浸出剂体积与干污泥质量的比(ω)为10 mL/g。再采用硫酸作为浸出剂、焦亚硫酸钠作为还原剂进行二次酸浸,在硫酸与污泥质量比为1.3、焦亚硫酸钠与污泥质量比为0.3、ω为5 mL/g、浸出温度85℃、浸出时间20 min的最佳工艺条件下,Co、Ni、Cu、Mn和Zn的浸出率分别达92.45%、93.48%、89.52%、97.78%和94.79%。经XRD表征,浸出后污泥中未见原污泥中的矿物相,说明原污泥中的矿物几乎全部被溶解。     

黄钠铁矾法氧化去除废锂电池硫酸浸出液中的铁

废锂电池中含有的Co、Ni和Cu等金属具有回收价值,Fe的存在降低了有价金属的回收效率。为去除废锂电池硫酸浸出液中的Fe,采用黄钠铁矾法分别以氯酸钠和过氧化氢作为氧化剂氧化除Fe,并优化了过氧化氢作为氧化剂的除Fe工艺参数。实验结果表明:过氧化氢作为氧化剂的除Fe效果好于氯酸钠;在n(H2O2)∶n(Fe)=0.5、初始溶液pH为1.8、终点pH为2.5、反应时间为2.0 h、搅拌速率为500 r/min的最佳工艺条件下,初始ρ(Fe)为0.212g/L的硫酸浸出液经除Fe处理后ρ(Fe)小于0.004 g/L,Fe去除率达98.0%,Co、Ni和Cu的损失率分别为1.04%、2.17%和1.41%。     

Use pattern of pesticides and their predicted mobility into shallow groundwater and surface water bodies of paddy lands in Mahaweli river basin in Sri Lanka

Pesticides applied on agricultural lands reach groundwater by leaching, and move to offsite water bodies by direct runoff, erosion and spray drift. Therefore, an assessment of the mobility of pesticides in water resources is important to safeguard such resources. Mobility of pesticides on agricultural lands of Mahaweli river basin in Sri Lanka has not been reported to date. In this context, the mobility potential of 32 pesticides on surface water and groundwater was assessed by widely used pesticide risk indicators, such as Attenuation Factor (AF) index and the Pesticide Impact Rating Index (PIRI) with some modifications. Four surface water bodies having greater than 20% land use of the catchment under agriculture, and shallow groundwater table at 3.0 m depth were selected for the risk assessment. According to AF, carbofuran, quinclorac and thiamethoxam are three most leachable pesticides having AF values 1.44 × 10^?2, 1.87 × 10^?3 and 5.70 × 10^?4, respectively. Using PIRI, offsite movement of pesticides by direct runoff was found to be greater than with the erosion of soil particles for the study area. Carbofuran and quinclorac are most mobile pesticides by direct runoff with runoff fractions of 0.01 and 0.08, respectively, at the studied area. Thiamethoxam and novaluron are the most mobile pesticides by erosion with erosion factions of 1.02 × 10^?4 and 1.05 × 10^?4, respectively. Expected pesticide residue levels in both surface and groundwater were predicted to remain below the USEPA health advisory levels, except for carbofuran, indicating that pesticide pollution is unlikely to exceed the available health guidelines in the Mahaweli river basin in Sri Lanka.     

Determination of radionuclide levels in rainwater using ion exchange resin and γ-spectrometry

The evaluation of radioactivity accidentally released into the atmosphere involves determining the radioactivity levels of rainwater samples. Rainwater scavenges atmospheric airborne radioactivity in such a way that surface contamination can be deduced from rainfall rate and rainwater radioactivity content. For this purpose, rainwater is usually collected in large surface collectors and then measured by γ-spectrometry after such treatments as evaporation or iron hydroxide precipitation. We found that collectors can be adapted to accept large surface (diameter 47 mm) cartridges containing a strongly acidic resin (Dowex AG 88) which is able to quantitatively extract radioactivity from rainwater, even during heavy rainfall. The resin can then be measured by γ-spectrometry. The detection limit is 0.1 Bq per sample of resin (80 g) for ¹³⁷Cs. Natural ⁷Be and ²¹⁰Pb can also be measured and the activity ratio of both radionuclides is comparable with those obtained through iron hydroxide precipitation and air filter measurements. Occasionally ²²Na has also been measured above the detection limit. A comparison between the evaporation method and the resin method demonstrated that 2/3 of ⁷Be can be lost during the evaporation process. The resin method is simple and highly efficient at extracting radioactivity. Because of these great advantages, we anticipate it could replace former rainwater determination methods. Moreover, it does not necessitate the transportation of large rainwater volumes to the laboratory.     

经过水泥固化的重金属废物的穿透渗漏实验

采用穿透渗漏实验方法研究了经水泥固化的重金属废物的长期渗漏行为。用由Ｐｂ＾２＋、Ｚｎ＾２＋、Ｃｕ＾２＋、Ｎｉ＾２＋和Ｃｒ＾６＋５种重金属组成的合成废物样品进行２组实验。实验研究了渗漏实验液流速、ＰＨ的变化和金属渗漏能力对固体废物长期渗漏行为的影响。     

江苏省武进市高产水稻田氮素渗漏损失研究

小区试验与农户调查研究结果表明 ,2 87kg/hm2施氮量宜作为武进市高产水稻的适宜施氮量 ,氮肥的过多施用不仅导致秸秆对氮素的奢侈吸收 ,也加重氮肥对渗漏水的污染。进一步降低水稻田施氮水平 ,又保持高产的水稻生产技术尚待开发。