零价铁-克雷伯氏菌联合体系对亚甲基蓝溶液的脱色性能

以零价铁(ZVI)和一株高效脱色菌克雷伯氏菌yl-1作为联合体系,研究其对亚甲基蓝溶液的脱色性能,并采用单因素实验及中心组合设计-响应面分析法(CCD-RSM法)对该过程的脱色条件进行优化。实验结果表明:相比于单独ZVI体系和单独yl-1脱色菌体系,ZVI-脱色菌联合体系的脱色率分别提高了40%和10%;在初始pH为8、初始亚甲基蓝质量浓度为250 mg/L、ZVI投加量为4.0 g/L、反应温度为33℃的最优条件下,ZVI-脱色菌联合体系对亚甲基蓝脱色反应液的脱色率为91.33%。     

Screening of wood rotting fungi potentially useful for the degradation of organic pollutants

Many papers have shown that white rot fungi can degrade aromatic pollutants under laboratory conditions, but few report field scale trials. Here we report the first steps in the development of a remediation system for Greek conditions. A review of the available organochlorine compound pollution information in Greece is presented. White rot fungi isolated from sites in Greece have been screened for growth rate and ligninolytic activity, using decolourisation of the dye Poly R-478 as an indicator of enzyme activity. Use of white rot fungi under field conditions in Greece will require bioaugmentation to be effective at high temperatures and low water activity for much of the year. The most potent strains have been selected under a range of conditions and have been challenged with priority pollutants to determine their degradative ability under laboratory conditions and subsequently ex situ in soil.     

Phytoremediation in subtropical Hawaii—A review of over 100 plant species

Phytoremediation is an emerging remediation technology that utilizes plants and microbes to clean up contaminated air, soil, and water. Tropical and subtropical environments have an advantage in that long plant‐growing seasons and increased soil temperature can accelerate phytoremediation processes. Various contaminated sites in Hawaii have been addressed using this technology. In this article, work progress and advances of phytoremediation are briefly reviewed and exemplified with seven chemically contaminated sites in Hawaii. The investigations were performed for one or more of the following remediation needs: explosive residues, hydrocarbons, pesticide residues, soil stabilization, and slaughterhouse wastewater. In this unique article, studies of testing of over 100 plant species for remediation are reviewed and documented. The general trend leads one to consider that salt‐ and/or drought‐tolerant plants can bear other potential stress‐inducing conditions. © 2004 Wiley Periodicals, Inc.     

In-Situ Phytoremediation of Pahs Contaminated Soils Following a Bioremediation Treatment

Phytoremediation of pollutants in soils is an emerging technology, using different soil-plant interaction properties. For organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), phytodegradation seems to be the most promising approach. It occurs mostly through an increase of the microbial activity in the plant rhizosphere, allowing the degradation of organic substances, a source of carbon for soil microbes. Despite a large amount of available data in the literature concerning laboratory and short term PAH phytodegradation experiments, no actual field application of such technique was previously carried out. In the present study, a soil from a former coking plant was used to evaluate the feasibility and the efficiency of PAH phytodegradation in the field during a three years trial and following a bioremediation treatment. Before the phytoremediation treatment, the soil was homogenized and split into six independent plots with no hydrological connections. On four of these plots, different types of common plant species were sowed: mixture of herbaceous species, short cut (P1), long cut (P2), ornamental plants (P3) and trees (P4). Natural vegetation was allowed to grow on the fifth plot (P5), and the last plot was weeded (P6). Each year, representative sampling of two soil horizons (0–50 and 50–100 cm) was carried out in each plot to characterize the evolution of PAHs concentration in soils and in soils solution obtained by lixiviation. Possible impact of the phytoremediation technique on ecosystems was evaluated using different eco- and genotoxicity tests both on the soil solid matrix and on the soil solution. For each soil horizon, comparable decrease of soil total PAHs concentrations were obtained for three plots, reaching a maximum value of 26% of the initial PAHs concentration. The decrease mostly concerned the 3 rings PAHs. The overall low decrease in PAHs content was linked to a drastic decrease in PAHs availability likely due to the bioremediation treatment. However, soil solutions concentration showed low values and no signficant toxicity was characterized. The mixture of the herbaceous species seemed to be the most promising plants to be used in such procedure.     

The potential of foliar treatments for enhanced phytoextraction of heavy metals from contaminated soil

Phytoextraction is the plant‐based removal of inorganic contaminants from the soil by root absorption and subsequent translocation to harvestable plant parts. The efficiency of this technique is limited by the phytoavailability of these contaminants in the soil and the root‐to‐shoot transport. To enhance the phytoextraction efficiency, the use of soil amendments has been widely investigated. Potential risks such as increased ecotoxicological effects and leaching of mobilized contaminants caution against the use of persistent mobilizing agents. The potential use of foliar amendments to enhance mineral absorption and/or translocation offers prospects for complementing or substituting soil amendments for enhanced phytoextraction purposes. This study presents an explorative screening to evaluate the feasibility of this approach. Helianthus annuus giganteus plants were grown in moderately contaminated dredged sediment for ten weeks, with daily foliar treatments from week six onward: (1) distilled water (control), (2) magnesium‐ethylenediaminetetraacetic acid (Mg‐EDTA), (3) diethylenetriaminepentaacetic acid (DTPA), (4) nitrilotriacetic acid (NTA), (5) citric acid, (6) oxalic acid, (7) calcium acetate, (8) ammonium thiocyanate (NH₄SCN), and (9) cystein. Applied doses varied between treatments based on plant tolerance: 15 μmol per plant for cystein, 60 μmol per plant for DTPA and NH₄SCN, 180 μmol per plant for Mg‐EDTA and NTA and 400 μmol per plant for the organic acids. At the end of the experiment, shoot accumulation of cadmium, chromium, copper, iron, manganese, nickel, lead, and zinc was evaluated. © 2004 Wiley Periodicals, Inc.     

Phytoremediation of arsenic in mining‐contaminated areas: The future of transgenic technology

A considerable number of contaminated mining sites in Europe and other parts of the world pose environmental hazards. Given the multifaceted benefits of phytoremediation, screening of plant communities grown in contaminated areas is being conducted to identify hyperaccumulating plant species. A few arsenic (As) hyperaccumulating plants are found in tropical countries; however, generally, they are not grown in contaminated mining sites of cold and temperate countries (Europe and other parts of the world). The transgenic plants identified to date are not believed to be suitable for commercial use of phytoremediation. A few tolerant plant species in mining sites that are found to have elevated As levels primarily concentrate As in their roots. The remediation potential of many of these tolerant plants is limited because of their slow growth and low biomass. Therefore, phytostabilization of contaminated mining sites using tolerant plant species with high biomass and a more extensive root system is the only solution to date in Europe and some other parts of the world. © 2010 Wiley Periodicals, Inc.     

Potential of Rhizobacteria for Improving Lead Phytoextraction in Ricinus communis

Heavy metal–resistant bacterial strains were isolated from heavy metal–contaminated soils and identified as Bacillus sp. and Leclercia adecarboxylata on the basis of their morphology and biochemical characters using the VITEK 2 Systems Version 05.02. The heavy metal and antibiotic resistance of the isolates were studied. A green house pot experiment was conducted to examine the bacterial ability to extract the lead in soils and for their effect on lead uptake by Ricinus communis in an artificially contaminated soil. Bacterial inoculated pots increased the biomass of the R. communis compared to the uninoculated control, and the root growth of the plant was also increased in the inoculated pot. The experimental data confirmed that lead‐resistant bacteria have a pronounced effect on heavy metal uptake in plants, which may provide a new bacterially assisted phytoremediation of metal‐contaminated soils. © 2013 Wiley Periodicals, Inc.     

无机-有机复合絮凝剂PACSAM的制备及其脱色性能

以聚合氯化铝（PAC）和淀粉-丙烯酰胺接枝聚合物（ST-AM）为原料,合成了一种新型的无机-有机复合絮凝剂（PACSAM）。考察了PACSAM对活性染料、直接染料模拟印染废水及实际印染废水的脱色效果,并初步探讨了絮凝机理。实验结果表明：在很宽的pH范围内,PACSAM均表现出了良好的脱色性能;在PACSAM加入量为25m g/L时,PACSAM对实际印染废水的脱色率、COD去除率、浊度去除率分别为96.4%,92.1%,98.5%,废水处理效果明显好于壳聚糖和PAC。PACSAM的絮凝机理包括化学反应、分子间氢键、电中和及架桥作用等。     

Selection of Autochthonous Plant Species from SE Spain for Soil Lead Phytoremediation Purposes

Mining activity in SE of Spain, in the west Mediterranean coast, originated more than two millenniums ago. It has generated huge areas affected by heavy metals contamination, especially of lead, which is possibly one of the most important. Investigations related to the selection of autochthonous plant taxa from a typical Spanish Mediterranean area, useful for phytoextraction and phytostabilization purposes in these polluted areas are shown. Under these edaphoclimatic conditions 12 interesting species were considered, from them six taxa were chosen for further studies. Some plant species have been proposed either for phytoextraction or phytostabilization purposes. Recommendations for further research have been discussed.     

Decolorization and estrogenic activity of colored livestock wastewater after electrolysis treatment

Livestock wastewater is treated by activated sludge treatment. Untreated livestock wastewater has high estrogen activity because animal excreta contains estrogen. When activated sludge treatment is applied, the estrogen activity declines or is lost. However, the color of treated livestock wastewater is deep brownish-red because of the decomposition of organic compounds or the synthesis of metabolites. Discharging colored wastewater to the environment could cause some problems, so it is necessary to decolorize colored wastewater before it is discharged. It has been suggested that electrolysis decolorization technology is suitable for treating colored wastewater; however, the process produces volatile organic compounds (VOCs). In fact, little research has been conducted with reference to estrogen activity in wastewater that has undergone electrolysis, especially on the contribution of the electrolysis decolorization process to estrogen activity, i.e., the possibility of resynthesis of some substance with estrogen activity due to resolved and metabolized colored components. In this study, the concentration of VOC was measured for various electrolysis conditions, and estrogen activity was examined using a yeast two-hybrid assay. From the results, decolorization of colored livestock wastewater by electrolysis was possible, and the VOC generation during electrolysis could be controlled depending on the electrolysis conditions. Estrogen activity in colored livestock wastewater disappeared on electrolysis decolorization.     

Uptake of perchlorate by vegetation growing at field sites in arid and subhumid climates

Previous greenhouse and field studies show that terrestrial and aquatic vegetation, including trees, grasses, and agricultural produce grown on perchlorate‐contaminated soil or with perchlorate‐contaminated irrigation water, accumulate perchlorate mainly in their leaf tissue. The phytoaccumulated perchlorate poses potential ecological risk by either contaminating the food chain of humans and animals or recycling in the ecosystem as leaf litter fall that accumulates on topsoil. In this study, the uptake and phytoaccumulation of perchlorate in terrestrial and aquatic vegetation growing at two perchlorate‐contaminated sites (the Longhorn Army Ammunition Plant [LHAAP] in Karnack, Texas, and the Las Vegas Wash [LVW], Nevada) was monitored during multiple growing seasons. The LHAAP site is located in a subhumid climate, while the LVW site is located in an arid climate. All vegetation species collected from both sites contained quantifiable levels of perchlorate. The detected concentrations varied with the type of plant species, amount of perchlorate concentration in soil, and season and stage of plant maturity. The highest perchlorate concentrations were measured in willows (Salix nigra), crabgrass (Digitaria spp.), and Bermuda grass (Cynodon dactylon) at the LHAAP, while salt cedar (Tamarix ramosissima) at the LVW phytoaccumulated the highest mass of perchlorate. The concentrations of perchlorate measured in plant leaves growing over contaminated soils at multiple LHAAP locations did not reveal the strong seasonal variability observed at the LVW site. The slow rate of phytodegradation of the perchlorate fraction taken up by plants during the growing season explained the detection of higher perchlorate concentrations in leaves collected later in the growing season (fall) and in senesced leaves compared to younger, live leaves. This proves that senesced plant leaves potentially recycle perchlorate back into the soil on which plant litter collects. To minimize the potential recycling of perchlorate during phytoremediation, it is recommended that senesced leaves be collected and composted or phytoremediation be designed to enhance rapid rhizodegradation (rhizoremediation). © 2007 Wiley Periodicals, Inc.     

Phytoremediation of arsenic‐contaminated soil as affected by the chelating agent CDTA and different levels of soil pH

Elevated levels of arsenic can pose a major threat to both human health and the environment. The phytoremediation of heavy metals from soil is emerging as a cost‐effective technology for the remediation of contaminated soils. The present greenhouse study was undertaken to identify plants capable of tolerating and accumulating high concentrations of arsenic. Asparagus fern and rye grass were found to tolerate and accumulate more than 1,100 ppm of arsenic in plant tissue. Arsenic uptake as affected by different levels of the chelating agent trans‐1, 2‐ cyclohexylenedinitrilotetraacetic acid (CDTA) and soil pH were also studied. The application of 5 mmol kg^?1 of CDTA to arsenic‐contaminated medium loam field soil enhanced the accumulation of arsenic by the test plants. Under these conditions, plants accumulated up to 1,400 ppm of arsenic as compared to 950 ppm by the plants grown in soil containing 1,200 ppm of arsenic but without any amendment of the chelating agent. Plants grown in field soil of pH 5 containing 300 ppm of arsenic absorbed higher concentrations of arsenic than at other tested pH levels. Corresponding reductions in arsenic content of soil after plant harvests were observed. © 2001 John Wiley & Sons, Inc.     

Phytoremediation: The uptake of metals and metalloids by rhodes grass grown on metal‐contaminated soil

An experiment was performed to examine the phytoremediation potential of Rhodes grass (Chloris gayana Kunth cv. ‘Pioneer’). The study sought to determine substrate tolerance, biomass production, and plant uptake of antimony (Sb), arsenic (As), cadmium (Cd), lead (Pb), silver (Ag), and zinc (Zn). The plants were grown on weight percent mixtures (5 percent, 15 percent, 25 percent, 35 percent, 50 percent) of a vertisol soil and base‐metal mine tailings (7–2,040 μg/g As, ≥ 30 μg/g Cd, 30–12,000 μg/g Pb, and 72–4,120 μg/g Zn). The 5 percent and 15 percent amendment of mine tailings increased the biomass production of Rhodes grass (from 0.1 g/plant to ≈ 3.5 g/plant) without appreciably elevating plant concentrations of the elements. Plant growth decreased by greater than 50 percent for the substrate containing greater than 25 percent tailings (3,023 μg/g Pb and 1,084 μg/g Zn). Reduced biomass production coincided with maximal Zn uptake by Rhodes grass (249.8 μg/g), indicating tailings induced phytotoxicity. The total concentrations of metals and metalloids tolerated by Rhodes grass in the plant‐growth medium indicated hypertolerance to elevated As, Pb, and Zn concentrations. Partial extraction of the plant‐growth medium determined that plant‐available Pb was ten times higher than Ag, As, Cd, and Zn availability. However, Rhodes grass accumulated low levels of Pb, in addition to As and Cd, over the experimental range, indicating low fodder toxicity risk to browsing livestock. This study concludes that if there are no invasive species issues associated with conservation land uses, Rhodes grass is well suited to metalliferous mined land revegetation and would therefore be highly effective for such programs in subtropical and tropical Australia. © 2005 Wiley Periodicals, Inc.     

Effect of chelating agents in phytoremediation of heavy metals

Chelate‐assisted metal uptake by plants has only recently been discovered in the remediation industry. The simultaneous accumulation of lead, arsenic, copper, and cadmium in plants after application of chelating agents to soil is a promising technology enhancement for phytoremediation. One of the most powerful and commonly used chelating agents is ethylene diamine tetra acetic acid (EDTA), which forms complexes with many of the metal contaminants within the natural environment. This study was conducted to determine the efficiency of an emergent wetland plant species Typha sp. and floating wetland macrophytes such as Pistia sp., Azolla sp., Lemna sp., Salvinia sp., and Eichhornia sp. in phytoremediation of various heavy metals with addition of a chelating agent such as EDTA. EDTA addition to the treatment systems increased the uptake of heavy metals by plants, which was much pronounced with lead and copper. However, the pattern of uptake by plants was similar as that of heavy metals without EDTA amendments. © 2012 Wiley Periodicals, Inc.     

Field trial experiment: Phytoremediation with Salix sp. on a dredged sediment disposal site in Flanders,Belgium

Remediation of heavy metal contamination in soil is a widespread environmental issue. Conventional remediation techniques are invasive and often too expensive, particularly if large areas of soil are contaminated. Phytoremediation is the use of plants to remediate soil and groundwater. Phytoremediation of inorganic comtaminants such as metals can be further catagorized into phytostabilization and phytoextraction. These techniques have gained an increasing amount of attention and research over the last ten years. Phytoextraction of heavy metals and periodical removal of harvestable plant parts results in a gradual decrease of pollutant levels in the top soil. Woody species such as Salix sp. (willow) do not represent the fastest phytoextraction procedure compared to uptake by herbaceous species; however, they offer the added advantage of possible reuse of the produced biomass (wood) for the production of renewable energy. Here we present the results of a field experiment conducted to evaluate the use of Salix to remediate soil contaminated with cadmium and zinc at a dredged sediment disposal site in Flanders, Belgium. © 2003 Wiley Periodicals, Inc.     

用白泥和赤泥制备烟气脱硫剂

以碱厂白泥和钢厂赤泥为主要原料,研究了制备复合金属氧化物成型烟气脱硫剂的工艺;考察了m（白泥）：m（赤泥）、白泥和赤泥平均粒径、黏结剂、造孔剂对脱硫剂活性的影响。脱硫剂最佳制备工艺条件为m（白泥）：m（赤泥）=2：1,白泥和赤泥粒径越小越好,黏结剂为Na,造孔剂为Zb,加水混匀,挤条成型,烘干后高温焙烧制得;脱硫剂的最高脱硫率为99．83％,脱硫剂脱硫12．30h后穿透硫容为15．20％。     

Reducing salinity and organic contaminants in the Pearl Harbor dredged material using soil amendments and plants

Phytoremediation is an emerging technique that can be used to economically remediate sites contaminated with trace elements and/or man‐made organic contaminants. This technique was used on Pearl Harbor (Oahu, Hawaii) dredged material (PHDM) containing polycyclic aromatic hydrocarbons (PAHs) and some heavy metals. The dredged material was first amended with a high‐calcium soil (Waialua Mollisol) and a biosolids‐based compost at different proportions to yield varying salinity levels. A mixture that yielded an electrical conductivity (EC, a measure of salinity) of the saturated paste extract of 15 to 20 dS/m was identified and used to evaluate the salt tolerance of five plant species. Relative germination and one‐month‐old biomass indicated that common bermuda grass (Cynodon dactylon), seashore paspalum (Paspalum vaginatum), beach pea (Vigna marina), and cow pea (Vigna unguiculata) can produce at least 40 percent of biomass of the control at an EC of approximately 18 dS/m, suggesting the four plants are relatively salt tolerant. In contrast, Desmodium intortum either did not germinate or died within two weeks after germination at the same salinity level. A subsequent greenhouse experiment, using mixtures of the PHDM (0 or 25 percent dry weight), organic amendments (10 percent leucaena green manure or biosolids‐based compost), and a Mollisol (65 or 90 percent dry weight) in 6‐liter pots containing 4 kilograms of material yielded the following results: (1) A combination of transplanted seashore paspalum, seeded bermuda grass, and seeded beach pea was effective in taking up sodium (Na), thereby reducing salinity and making the medium more amenable to diversified microbes and plants, which may be effective PAH degraders; (2) total PAH concentration was reduced by about 30 percent after three months of active plant growth, but degradation of individual PAH members varied significantly, however; (3) leguminous green manure, as a soil amendment, was more effective than compost for use in bio‐ and/or phytoremediations; and (4) soil amendments, when applicable, could supplement living plants in reducing organic contaminants, such as PAHs. © 2002 Wiley Periodicals, Inc.     

Root penetration through sealing layers at mine deposit sites.

To prevent acid mine drainage arising from oxygen and water penetration of sulphide-rich mine tailings, the tailings are covered with layers of dry sealing material. Plant roots have a great ability to penetrate dense materials, and if the roots are able to penetrate the sealing layer of a tailings deposit, its oxygen-shielding properties could be reduced. The objective of this study was to evaluate whether plant roots are able to penetrate sealing layers covering mine tailings deposits. Root penetration into layers of various sealing materials, such as clayey moraine (clay, 8-10%; silt, 22-37%; sand, 37-55%; gravel, 15-18%), moraine (unspecified), 6-mm bentonite (kaolin clay) fabric, lime and clay, Cefyll (mixture of pulverized coal fly ash, cement and water) and a mixture containing biosludge (30-35%) and bioashes (65-70%), was investigated. In the field, roots were studied by digging trenches alongside vegetation growing in 3- and 10-year-old mine sites. In the greenhouse root growth of Betula pendula, Pinus sylvestris, Poa pratensis and Salix viminalis were studied in compartments where the plants had been growing for 22 months. The results from the field experiment indicated that roots are able to penetrate both deep down in the cover layer (1.7 m) and also into the sealing layers of various materials, and even to penetrate hard Cefyll. The addition of nutrients in the top cover reduced deep root growth and thereby also penetration through the sealing layer. Low hydraulic conductivity of the sealing layer or a thick cover layer had less effect on root penetration. In the greenhouse experiment roots did not penetrate the thin bentonite fabric, due to low pH (2.1-2.7) that was created from the underlying weathered mine tailings. The clayey moraine was penetrated by all species used in the greenhouse experiment; Pinus sylvestris had the greatest ability to penetrate. To prevent root penetration of the other sealing layer, a suitable condition for the plants should be created in the upper part of the cover layer, namely a sufficient amount of plant nutrients. However, to define such a condition is difficult since different plant species have different requirements.     

Remediation of metal-contaminated sites using plants

Heavy metal contamination of soil resulting from anthropogenic sources poses a significant challenge in many industrialized societies. The current technologies employed for removal of heavy metals often involve expensive ex-situ processes requiring sophisticated equipment and removal, transportation, and purification of the soil. Generally, in-situ remedial technologies are favored to ex-situ methods for detoxification, neutralization, degradation, or immobilization of contaminants. In-situ bioremediation is increasingly favored because of its effectiveness and low cost. A new type of bioremediation, known as vegetative remediation or “phytoremediation,” uses metal-tolerant hyperaccumulator plants to take up metal ions from soils and store them in their aboveground parts. To select the appropriate phytoremediation technology, one must understand the technical feasibility, cost effectiveness, and availability of the suitable plant species. Equally important is determining whether the site's soil conditions are optimal to enhance or restore the soil biological activity. Before phytoremediation can be exploited on a contaminated site, greenhouse-scale confirmatory testing is necessary to measure plant uptake and correlate shoot metal concentrations to available soil metals. These tests also validate that the harvesting and subsequent disposal of metal-containing plant tissues are environmentally safe and manageable.     

Arsenic,manganese, and cyanide removal in a tailing storage facility for a gold mine using phytoremediation

In this study, six selected plants (Acacia mangium, A. auriculiformis, Leucaena leucocepphala, bamboo, Pennisetum purpureum, and Vetiveria zizanioides) were cultivated in a mine tailing storage facility in a gold mine area. P. purpureum, a monocot species, provided the highest phytoremediation efficiency. Therefore, it is a potentially appropriate plant for site remediation. It is interesting that P. purpureum is perennial, meaning it can be easily planted and requires less effort and input for care with the ability to flourish year round. Thus, this study recommends using P. purpureum for phytoremediation of heavy metals and cyanide in gold mine areas.