低浓度含铀废水处理技术的研究进展

各种人为因素使得环境中的铀及其化合物越来越多,对水体造成了放射性污染。在分析环境中低浓度铀来源的基础上,介绍了对低浓度铀污染水体进行处理的最新技术,并着重探讨了应用植物修复技术处理铀污染的研究现状与发展趋势。     

Liquefaction of metal-contaminated giant reed biomass in acidified ethylene glycol system： Batch experiments

Giant reed is a suitable pioneer plant for metal-contaminated soil phytoremediation,however,it is imperative to dispose the metal-contaminated biomass after harvesting.The liquefaction of metal-contaminated giant reed biomass in ethylene glycol system with sulfuric acid as catalyst for the precursors of polyurethane compounds was studied.The results show that giant reed biomass from metal-contaminated soil is potentially liquefied and significantly affected by solvent/solid ratio,liquefaction temperature and liquefaction time （P〈0.05）.The liquefaction rate of biomass in acidified ethylene glycol system can reach 85.2% with optimized conditions of 60 min,170 ℃,3% sulfuric acid and solvent/biomass ratio of 5：1.The hydroxyl value of liquefied products is of 481 mg KOH/g while reactive hydroxyl groups of them are abundant,which is promised as potential precursors for polyurethane compounds.The solvent liquefaction is a potential method to dispose the metal-contaminated biomass,however,the containing-metal liquefied products should be studied deeply in order to get the suitable precursors in future.     

How do the plants used in phytoremediation in constructed wetlands,a sustainable remediation strategy,perform in heavy‐metal‐contaminated mine sites?

This review draws on knowledge for the treatment of heavy‐metal leachate in contaminated mine sites. Mine waste rock dumps and tailings generate a continuous stream of metalliferous and saline leachate over the long term. The mining industry has many legacy sites, which have compromised aquatic ecosystems and groundwater because of heavy‐metal contamination. Chemical and engineering methods are available and have been extensively utilised. However, these methods require intensive energy and often produce substantial volumes of secondary waste. We therefore argue in favour of phytoremediation as a sustainable remediation strategy leading towards efficient and sustainable metal removal and immobilisation through constructed wetlands.     

放射性重金属污染水体的植物修复技术

分析水体中放射性重金属的来源,探讨影响植物修复放射性重金属污染水体的因素,对用于修复放射性重金属污染水体的植物种类、修复机制和主要技术进行综述,并对研究方向作出展望.     

甲基叔丁基醚的降解技术研究进展

随着汽油添加剂甲基叔丁基醚（MTBE）的普及使用和用量增加,其对环境和人体的危害受到了人们的普遍重视。主要介绍了MTBE在污染环境中的检测分析方法和降解技术研究进展,包括：物理吸附和曝气吹除、化学降解、生物降解和植物修复技术。分析了各种技术的原理及特点后指出,化学和生物降解MTBE可以将其对环境的危害降低到最低限度,是在修复由MTBE污染的环境时优先考虑的处理技术。     

Use of native species and biodegradable chelating agents in the phytoremediation of abandoned mining areas

BACKGROUND: The application of phytostabilization and assisted phytoextraction to the remediation of abandoned mining areas can be a valuable method to reclaim these areas without modifying soil and landscape characteristics. An in situ application of a continuous phytoextraction technique was carried out in the area of Campo Pisano (Sardinia, Italy), followed by a laboratory assisted phytoextraction test using the biodegradable chelating agents methylglycine diacetic acid (MGDA) and iminodissuccinic acid (IDSA). The plants used were Scrophularia canina subsp. bicolor, Cistus salviifolius and Teucrium flavum subsp. glaucum. RESULTS: The plant that accumulated more Pb was T. glaucum (353 mg kg^?1) while C. salviifolius demonstrated better ability to accumulate Zn (1560 mg kg^?1). S. bicolor showed a better tolerance to metals but accumulated 119 mg kg^?1 of Pb. Accumulation of metals immediately after chelant application was up to 300 mg kg^?1 of Pb and 3000 mg kg^?1 of Zn which did not further increase during the assisted phytoextraction experiment. CONCLUSION: The plant that demonstrated to be most suitable for phytoremediation application was S. bicolor due to its higher biomass production and tolerance to metals. The low cation exchange capacity and the high concentration of Ca and Mg in soil determined a low chelant effectiveness. Copyright © 2009 Society of Chemical Industry     

Phytoremediation: the state of rhizosphere ‘engineering’ for accelerated rhizodegradation of xenobiotic contaminants

Phytoremediation has emerged as the method of choice for cleaning up a broad range of environmental contaminants. One process through which plants render some xenobiotic organic contaminants innocuous in soil involves plant–microbe interactions in which root exudates stimulate entire microbial communities, or induce specific enzymes in competent individuals to cause enhanced rhizodegradation. For some contaminants these inherent processes can be slow; however, potentials exist for their improvement through rhizosphere manipulations. Although this requires a greater understanding than currently exists with respect to plant and microbe components and interactions involved in the biodegradation of xenobiotic contaminants, improved understanding is being achieved by advances in biochemical and molecular characterization, and visualization of rhizosphere phenomena. In combination with earlier knowledge of naturally‐occurring plant–microbe interactions such as the opine concept, this new knowledge considerably improves the opportunities for manipulating rhizosphere interactions to greatly accelerate rhizodegradation for routine practical implementation in the field. Copyright © 2007 Society of Chemical Industry     

植物修复技术在水环境污染控制中的应用

综述了国内外植物修复的研究进展,阐述了植物修复主要类型及机理。给出多种主要植物的修复特性。分别对重金属,无机营养元素N、P以及有机污染物的植物修复进行论述,认为凤眼莲、水花生和芦苇等水生植物对无机营养元素的修复具有综合功效,植物修复对残余农药、多环芳烃和硝基芳香化合物的治理效果显著。     

根际微生物促进下鱼腥草对镉的富集作用

初次探讨了鱼腥草在根际微生物的促进下对土壤镉的富集作用。研究表明当土壤中镉(Cadmium)含量在5mg•kg-1时,鱼腥草(Houttuynia cordata , HCT)对镉的富集率为2.86％,镉含量为10 mg•kg-1时富集率1.63％,鱼腥草对镉的吸收量最高可以达到培养前自身镉浓度的200倍（培养前鱼腥草镉含量0.1146 mg•kg-1,培养后最高达24.44 mg•kg-1）,说明鱼腥草对镉有很强的富集作用。研究中还发现,细菌、霉菌对镉的耐性很弱,而培养初期放线菌对镉的耐性很强,较高浓度镉可能刺激了放线菌的大量生长。并且在鱼腥草根系和微生物的联合作用下,土壤微生态系统能够保持较好的稳定性。因此植物-微生物联合修复重金属污染土壤技术,可以实现土壤的生态修复,拥有很大的应用前景。     

清除土壤重金属污染的植物修复技术

根据清除土壤重金属污染的机理不同，植物修复技术可分为植物固定、植物挥发和植物提取3种基本类型．与传统的土壤重金属污染治理技术比较，该技术存在成本低、利于环保、方便操作等优点，但同时也存在修复速度慢、受环境条件限制等局限性．今后研究的重点：寻找超累积植物并研究重金属富集的机理；通过基因工程发展植物修复技术；通过物理、化学和生物方法强化植物修复技术，如发展对环境安全的化学添加剂．