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。     

Effects of Puccinellia Distans and Tall Fescue on Modification of C/N Ratios and Microbial Activities in Crude Oil-Contaminated Soils

Abstract

Petroleum contamination of soil is a serious problem throughout oil-producing countries. One of the cost-effective options for removing contaminants from shallow soils is phytoremediation. Vegetation, by stimulating the microorganisms via releasing root exudates near the rhizosphere, may play an important role in the biodegradation of toxic organic chemicals in soil. This experiment investigates the efficiency of this emerging technology following the implementation of five plant species. The study was carried out in a greenhouse using crude oil–contaminated soil from sites around the Tehran Refinery. To study the effect of a water-absorbent agent, we also used hydrogel in this experiment. The microbial population and the C and N content of soil were assessed in the beginning, middle, and the end of the trial. Our findings show that Puccinellia distans and tall fescue could increase microbial population significantly. Hydrogel has a positive impact in this increasing and improved capability of Puccinellia distans for hydrocarbon degradation. C/N ratio for Puccinellia distans treatments decline from 39.57 to 35.     

铬污染土壤的修复

目前,许多铬盐厂正在进行铬渣无害化处理,速度快的已基本完成.随着铬渣治理的深入进行,渣场底部及附近铬污染土壤的修复亦提上日程.铬污染土壤的修复有其特殊性.各种地质条件形成的土壤含铬量相差很大,而土地的用途有很多种,对总铬和 6价铬的容忍性各不相同,故尚未见到铬污染土壤治理标准.介绍了对铬污染土壤修复指标有参考价值的资料.同时对铬污染土壤的修复技术进行了评述,介绍了5种修复技术.     

Zinc removal from hyperaccumulator Sedum alfredii Hance biomass

Leaching of heavy metals from Sedum alfredii Hance biomass was studied with ammonia-ammonium chloride solution as leaching agent. The research was carried out in two phases: 1) a leaching study to determine the zinc extraction efficiency of this leaching agent, and 2) a thermodynamic analysis to identify the likely reactions and stable Zn(II) species formed in the leaching systems. Taguchi orthogonal experiment, with four variable parameters, leaching temperature, molar ratio of NH₄Cl to NH_3, leaching time and solid-to-liquid(L/S) ratio, and each at three levels, was used to optimize the experiment parameters by the analysis of variances. The results indicate that leaching temperature has the most dominant effect on metal extraction performance, followed by molar ratio of NH₄Cl to NH₃, solid-to-liquid ratio and leaching time. The optimum condition was obtained as follows: temperature of 60°C, molecular ratio of NH₄Cl to NH₃ of 0.6, leaching time of 2 h and solid-to-liquid ratio of 5:1. The total zinc leaching efficiency under optimum conditions reaches 97.95%. The thermodynamic study indicates that the dominant species produced by the leaching process should be the soluble Zn(NH₃)₄₂⁺.     

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.     

Effects of added Cd on Cd uptake by oilseed rape and pai-tsai co-cropping

The experiment was designed to study whether the decrease of Cd in the rhizosphere of Zhongyouza Ⅰ,one breed of oilseed rapes （Brassicajunica） that can hyperaccumulate cadmium from the soil, can improve the living condition of less Cd-tolerant plant pai-tsai （Brassia chinensis） with their roots permitted to intermingle and develop coincident rhizosphere. The extent of rhizosphere interactions between Zhongyouza Ⅰ and pai-tsai was controlled by different root barriers, or without barrier. The results show that in the 10 and 20 mg/kg Cd treated soils, pai-tsai gets higher shoot mass and less Cd accumulation in its shoot than in the barrier treatments or in the mono cultures, when its roots are permitted to intermingle with those of Zhongyouza Ⅰ. Meanwhile, soil decontamination rates of Zhongyouza Ⅰ are not affected much by co-cropping with pai-tsai, they are 80.0% and 91.8% of that in the mono cultures of Zhongyouza Ⅰ, respectively. However, the co-cropping method in meliorating the living condition of pai-tsai is not obvious when Cd concentration in soil reaches 40 mg/kg, and soil decontamination rate decreases to 0.14, which is 58.3% of that in the mono culture. These results indicate that the oilseed rape Zhongyouza Ⅰ may alleviate Cd toxicity of surrounding less-tolerant species, and its ability of phytoremediation is not affected much at the same time, especially in the middle polluted soil.     

重金属污染土壤的植物修复技术研究进展

土壤重金属污染已成为全球性问题。污染土壤的传统治理方法成本高、效率低,并且还给生态环境带来其它危害。植物修复技术因成本较低、易被公众接受且无二次污染等优点越来越受到重视。介绍了植物修复技术的分类及超积累植物的来源、发展、筛选、应用,就植物修复技术的植物资源进行了综述,并对重金属污染土壤的植物修复技术进行了展望。     

植物修复铬污染土壤的研究进展

铬污染土壤的植物修复技术以其经济、高效和生态友好等优点成了众多修复技术中的佼佼者。文章归纳总结了土壤铬污染的来源及危害、铬污染土壤的植物修复以及植物与微生物的联合修复的最新进展,探讨了植物修复铬污染土壤存在的问题,展望了其发展趋势。     

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.