填闲作物防治菜田土壤硝酸盐污染的研究进展

探讨了通过调整蔬菜生产的轮作结构 ,运用生物修复的原理 ,引入适宜的深根系填闲作物对深层土壤硝酸盐吸收利用 ,以避免硝酸盐进一步淋失 ,提高氮素的利用率的可行性。填闲作物应选择生长迅速、生物量大、氮素累积能力强的作物 ,在考虑填闲作物防治硝酸盐淋溶的同时 ,要兼顾其经济利用价值 ,并指出结合深根系的填闲作物进行合理轮作是蔬菜安全生产及可持续发展的途径之一     

Nitrate in groundwater: an isotopic multi-tracer approach

In spite of increasing efforts to reduce nitrogen inputs into groundwater from intensive agriculture, nitrate (NO3) remains one of the major pollutants of drinking-water resources worldwide. Determining the source(s) of NO3 contamination in groundwater is an important first step for improving groundwater quality by emission control, and it is with this aim that we investigated the viability of an isotopic multi-tracer approach (delta15N, delta11B, 87Sr/86Sr), in addition to conventional hydrogeologic analysis, in two small catchments of the Arguenon watershed (Brittany, France). The main anthropogenic sources (fertilizer, sewage effluent, and hog, cattle and poultry manure) were first characterized by their specific B, N and Sr isotope signatures, and compared to those observed in the ground- and surface waters. Chemical and isotopic evidence shows that both denitrification and mixing within the watershed have the effect of buffering NO3 contamination in the groundwater. Coupled delta11B, delta15N and 87Sr/86Sr results indicate that a large part of the NO3 contamination in the Arguenon watershed originates from the spreading of animal manure, with hog manure being a major contributor. Point sources, such as sewage effluents, contribute to the NO3 budget of the two watersheds.     

改性粉煤灰在处理锑矿选矿废水中的应用

针对锑矿选矿废水中锑和丁基黄原酸钠严重超标的问题,用酸改性粉煤灰对其进行吸附处理.试验结果表明,当改性粉煤灰处理选矿废水的最佳质量体积比(g.mL-1)为1:100,pH值为3,静置时间为4h时,可以将选矿废水中的锑浓度从28.611mg.L-1降到0.05mg.L-1以下,去除率达99.8%以上;废水中的丁基黄原酸钠浓度可从0.373mg.L-1降到0.02mg.L-1以下,去除率达95.0%以上.处理废水后的改性粉煤灰用硫酸-硝酸浸提,浸出液中重金属离子浓度均低于国家浸出毒性标准,表明改性粉煤灰是一种很好的锑矿选矿废水处理剂.     

在沸石对高放废液水泥固化体中Cs~+浸出率的影响

文章主要研究模拟高放废液加入沸石预处理经碱矿渣水泥固化后Cs+的浸出性能。实验结果表明,处理含Cs+高放废液固化体中加入沸石,能使Cs+浸出率降低";两步法"掺入沸石固化体抗Cs+浸出性能更有所提高;pH值升高Cs+的吸附比增大。     

锰尾矿、矿渣浸出毒性及Cd、Pb溶出特性研究

锰尾矿、矿渣是锰生产过程中形成的废弃物,里面的很多物质都会在自然条件下如雨水淋溶而溶出,进入到土壤和水体中造成环境污染。通过对锰尾矿、矿渣进行浸出毒性实验;以及结合到当地的自然条件,考查浸泡体系pH值、温度、液固比的变化条件,对尾矿、矿渣中Pb、Cd溶出含量的影响,明确了锰尾矿、矿渣属于一般的工业固体废物,以及Pb、Cd的溶出特性。     

石油污染土壤异位淋洗修复研究进展

石油污染土壤异位淋洗修复是一种新兴的、经济高效的修复技术,是对生物修复的一种补充.异位淋洗修复有望促成石油污染土壤修复的系统化.本文讨论了石油污染土壤异位淋洗修复的原理、特点及其影响因素,阐述了石油污染土壤异位淋洗修复的最新研究进展,并对该领域今后的研究重点进行了展望.     

Effect of chemical and thermal activations on the properties of rice husk ash-based solidified wastes

Strength development,leachability and microstructure of heavy metals from the solidified waste using synthesis rice husk ash (sRHA) and lime blended at the weight ratio of 1:1 were used as binders.The heavy metal-containing sludge was used at the level of 0 wt.%,30 wt.%,and 50 wt.% dry weight,respectively.The sample specimens with and without 1.5 wt.% of sodium silicate (SiO 2 /Na 2 O=1.0) were cured under the ambient condition and elevated temperature curing at 50°C for 24 hr.Experimental results showed that the introduction of sodium silicate solution and elevated temperature curing to sRHA-based solidified waste containing 30 wt.% of heavy metal sludge gave one day strength of 20 kg/cm 2 compared to 0.9 kg/cm2 for the control sample.XRD patterns indicated that most metal-sulfides present in the sludge were appeared in the solidified waste and SEM coupled with EDX techniques reveal these metal-sulfide particles were trapped within the lime-sRHA matrices.In addition,cumulative leaching behavior by tank test (EA NEN 7375:2004) showed that solidified waste containing up to 30 wt.% of heavy metal sludge was suitable to dispose in a secured landfill.     

Cover crop effects on nitrous oxide emission from a manure-treated Mollisol

Agriculture contributes 40–60% of the total annual N₂O emissions to the atmosphere. Development of management practices to reduce these emissions would have a significant impact on greenhouse gas levels. Non-leguminous cover crops are efficient scavengers of residual soil NO₃, thereby reducing leaching losses. However, the effect of a grass cover crop on N₂O emissions from soil receiving liquid swine manure has not been evaluated. This study investigated: (i) the temporal patterns of N₂O emissions following addition of swine manure slurry in a laboratory setting under fluctuating soil moisture regimes; (ii) assessed the potential of a rye (Secale cereale L.) cover crop to decrease N₂O emissions under these conditions; and (iii) quantified field N₂O emissions in response to either spring applied urea ammonium nitrate (UAN) or different rates of fall-applied liquid swine manure, in the presence or absence of a rye/oat winter cover crop. Laboratory experiments investigating cover crop effects N₂O emissions were performed in a controlled environment chamber programmed for a 14 h light period, 18 °C day temperature, and 15 °C night temperature. Treatments with or without a living rye cover crop were treated with either: (i) no manure; (ii) a phosphorus-based manure application rate (low manure): or (iii) a nitrogen-based manure application rate (high manure). We observed a significant reduction in N₂O emissions in the presence of the rye cover crop. Field experiments were performed on a fine-loamy soil in Central Iowa from October 12, 2005 to October 2, 2006. We observed no significant effect of the cover crop on cumulative N₂O emissions in the field. The primary factor influencing N₂O emission was N application rate, regardless of form or timing. The response of N₂O emission to N additions was non-linear, with progressively more N₂O emitted with increasing N application. These results indicate that while cover crops have the potential to reduce N₂O emissions, N application rate may be the overriding factor.     

施磷对香溪河黄棕壤磷素淋失的影响研究

为了阐明香溪河流域黄棕壤在降雨条件下磷素通过淋溶流失的特征,采取室内连续淋洗的方法对香溪河黄棕壤的磷素淋溶特征进行了研究。结果表明,磷素的淋溶损失随着施磷水平的提高而增加,不同施磷量处理的淋洗峰值出现的时间无显著差异,淋失的磷主要以可溶性磷为主。施肥提高了各土层土壤的有效磷含量,施肥后土壤无机磷各形态磷之间并没有明显的相互转化规律,但是各组分所占无机磷比例的高低呈现O-PCa-PFe-PAl-P的规律。     

用铜钨合金废料制备氧化亚铜

用硝酸浸取铜钨合金废料中的铜,再用亚硫酸钠还原硝酸铜制备氧化亚铜。采用X射线衍射仪对氧化亚铜进行表征,考察了氧化亚铜产品对溶液中甲基橙的光催化效果,并与分析纯五水硫酸铜制备的氧化亚铜进行了对比。实验结果表明:在硝酸浓度为5.6 mol/L,硝酸用量为2.5 m L/g(为理论用量的1.5倍),浸取温度为40℃,浸取时间为6 h的最优浸取条件下,铜浸取率稳定在87%以上;在还原反应温度为80℃、还原反应时间为4h、硝酸铜浓度为0.8 mol/L的条件下,可制备得到较高纯度的氧化亚铜;在甲基橙质量浓度为20 mg/L、氧化亚铜加入量为2 g/L,500 W氙灯照射时间为2.5 h的条件下进行光催化反应,甲基橙降解率可达93%以上。与分析纯五水硫酸铜制备的氧化亚铜相比,两者形貌相似、光催化效果基本相当。