Bidens pilosa L. hyperaccumulating Cd with different species in soil and the role of EDTA on the hyperaccumulation

Environmental Science and Pollution Research - Investigating whether the same hyperaccumulator shows a high accumulation potential for different species of the same heavy metal in the soil has...     

脱硝催化剂的失活机理及其再生技术

采用SEM、XRD和XRF对电厂失活脱硝催化剂进行表征,探讨其失活原因和机理。结果表明:电厂脱硝催化剂失活的主要原因是活性组分V的流失及碱金属K、碱土金属Ca和As元素造成的催化剂中毒,烟气中飞灰的沉积也有一定的影响。经吹扫、水洗、酸洗和V负载再生,催化剂的各项物化性质基本恢复,NOx转化率基本达到新鲜催化剂的水平。水洗主要去除催化剂中的碱金属,酸洗主要去除As2O3,负载V补充催化剂活性组分。V再生催化剂在较高温度下的抗硫性能更好。     

Identification of cadmium-excluding welsh onion (Allium fistulosum L.) cultivars and their mechanisms of low cadmium accumulation

Purpose

Screening out cadmium (Cd) excluding cultivars of a crop in agricultural production is an effective way to prohibit Cd entering into food chain.

Methods

A judging criterion for Cd-excluding cultivars based on food safety was suggested and used in the identification of Cd-excluding welsh onion (Allium fistulosum L.) cultivars. A pot culture experiment was carried out to screen out Cd-excluding cultivars, of which the results were confirmed by plot experiments. The relevant factors of Cd accumulation in the pseudostem were analyzed and used in the correlation analysis aiming to study the low Cd accumulation mechanisms.

Results

The concentration of Cd in the pseudostem of welsh onions was 0.08?C0.20, 0.18?C0.41, and 0.26?C0.61?mg/kg fresh weight (FW) under three treatments (1.0, 2.5, and 5.0?mg/kg), respectively. The significant (p? ₃ ^? ?CN, and eight other elements in the tested welsh onion cultivars. Two cultivars were identified as Cd-excluding cultivars, mainly because the accumulation of Cd in their pseudostem was only 0.041?±?0.003 and 0.046?±?0.002?mg/kg FW, and 0.054?±?0.001 and 0.066?±?0.011?mg/kg FW, when growing in plots with Cd concentration of 0.49 and 0.99?mg/kg, respectively.

Conclusions

Ribentiegancongwang and Wuyeqi could be identified as Cd-excluding cultivars. Low bioaccumulation factor of the roots was the main mechanism of Cd-excluding welsh onion cultivars.     

Sulfate and glutathione enhanced arsenic accumulation by arsenic hyperaccumulator Pteris vittata L.

This experiment examined the effects of sulfate (S) and reduced glutathione (GSH) on arsenic uptake by arsenic hyperaccumulator Pteris vittata after exposing to arsenate (0, 15 or 30 mg As L⁻¹) with sulfate (6.4, 12.8 or 25.6 mg S L⁻¹) or GSH (0, 0.4 or 0.8 mM) for 2-wk. Total arsenic, S and GSH concentrations in plant biomass and arsenic speciation in the growth media and plant biomass were determined. While both S (18-85%) and GSH (77-89%) significantly increased arsenic uptake in P. vittata, GSH also increased arsenic translocation by 61-85% at 0.4 mM (p < 0.05). Sulfate and GSH did not impact plant biomass or arsenic speciation in the media and biomass. The S-induced arsenic accumulation by P. vittata was partially attributed to increased plant GSH (21-31%), an important non-enzymatic antioxidant countering oxidative stress. This experiment demonstrated that S and GSH can effectively enhance arsenic uptake and translocation by P. vittata.     

Growth responses of the newly-discovered Cd-hyperaccumulator Rorippa globosa and its accumulation characteristics of Cd and As under joint stress of Cd and As

Rorippa globosa has been identified as a newly-found Cd-hyperaccumulating species. In the present study, growth responses of Rorippa globosa and its accumulation characteristics of Cd and As were examined under joint stress of Cd and As. The results showed that Cd and As had an antagonistic effect on enhancing the growth of Rorippa globosa plants and Cd uptake and accumulation under the low concentration Cd and As treatments. When the concentration of Cd in the soil was 10 mg/kg and the concentration of As was 50 mg/kg, the highest growing height of the plant was up to 35.9 cm and the dry weight of the shoots was up to 2.2 g/pot, respectively. Meanwhile, the accumulation of Cd in the leaves under the joint stress was higher than that at the same level under single Cd pollution. However, there were synergic adverse effects on plant growth and Cd uptake under the combined pollution from a high concentration of Cd and As. Meanwhile, the accumulation of As in the roots was greater than that in the shoots, the translocation factor (TF) was ?0.3 and the bioaccumulation factor (BF) was ?0.6, thus showing that Rorippa globosa had an excluding effect on As uptake. These results confirmed that Rorippa globosa had a strong tolerant ability to the joint stress of Cd and As, and the potential for phytoremediation of soils contaminated by Cd and As.     

强化工程抗震营造安全家园

任何天灾都比不上地震,它能在短促的时间,波及广大的范围,造成巨大的损失,因此,地震是群灾之首。对于地震,人们既恐惧它,又想了解它,更想抵御和战胜它。266年前银川与平罗间大地震留给人们的记     

Identification of weed plants excluding the uptake of heavy metals

Using the field pot-culture and sample-analysis method, 54 weed species belonging to 20 families and 31 weed species belonging to 17 families were systematically examined as to whether they can exclude the uptake of heavy metals. After a systematic identification, it was determined that Oenothera biennis and Commelina communis were Cd-excluders and Taraxacum mongolicum was a Zn-excluder. O. biennis is a potential Cd-excluder, but also a potential Cu-excluder. The research raises the possibility of making a major breakthrough in the application of metal excluders for safe agro-production in the future.     

Phytoremediation of Cadmium-Contaminated Soils by Rorippa globosa Using Two-Phase Planting (5 pp)

Background Phytoextraction of contaminated soils by heavy metals can provide a great promise of commercial development. Although there are more than 400 species of hyperaccumulators found in the world, phytoremediation technology is rarely applied in field practice for remedying contaminated soils, partially due to low biomass and long growth duration for most of discovered hyperaccumulating plants. In order to enhance the metal-removing efficiency in a year, the two-phase planting countermeasure of phytoextraction by harvesting anthesis biomass was investigated on the basis of the newly found Cd-hyperaccumulator Rorippa globosa (Turcz.) Thell. with 107.0 and 150.1 mg/kg of the Cd accumulation in stems and leaves, respectively, when soil Cd added was concentrated to 25.0 mg/kg. Methods The field pot-culture experiment was used to observe the distribution property of R. globosa aboveground biomass and to examine characteristics of accumulating Cd by the plant at different growth stages. The concentration of Cd in plants and soils was determined using atomic absorption spectrophotometry (AAS). Results and Discussion The results indicated that the total dry stem and leaf biomass of R. globosa harvested at the flowering phase was up to 92.3% of that at its full maturity and the concentration of Cd in stems and leaves harvested at the flowering phase was up to 73.8% and 87.7% of that at the mature phase, respectively. The Cd-removing ratio by shoots of R. globosa harvested at the flowering phase was up to 71.4% of that at the mature phase. It was also found, by observing the growth duration of R. globosa, that the frostless period at the experiment site was twice as long as the growth time from the seedling-transplanted phase to the flowering phase of the hyperaccumulator. Conclusion R. globosa could be transplanted into contaminated soils twice in one year by harvesting the hyperaccumulator at its flowering phase based on climatic conditions of the site and traits of the plant growth. In this sense, the extraction efficiency of Cd in shoots of R. globosa increased 42.8% compared to that of at its single maturity when the plant was transplanted into contaminated soils after it had been harvested at its flowering phase and the plant accumulated Cd from soil at the same extraction ratio at its second flowering phase. Thus, the method of anthesis biomass regulation by the two-phase planting is very significant to increase the Cd-removing efficiency by phytoremediation used in practice over the course of a year. Recommendation and Outlook As for some hyperaccumulators that the growth duration from the seedling-transplanted phase to the flowering phase are short and the concentrations of heavy metals accumulated in their shoots at the flowering phase are high, the efficiency of phytoremediation can greatly be improved using the method of the two-phase planting.     

超高交联吸附树脂对有机物质甲苯的吸附热力学研究

比较了2种超高交联聚苯乙烯吸附树脂NDa99与ZH-04对甲苯的静态吸附行为.结果表明,在288～293 K和研究的浓度范围内,ZH-04、NDa99对甲苯的吸附平衡数据符合Freundlich和Langmuir吸附等温方程.吸附为放热过程,适当降低温度有利于吸附,并计算了甲苯在ZH-04和NDa99树脂上的吸附焓变、自由能变和熵变,对吸附行为进行了合理的解释,为废水处理提供一定的理论依据.     

树脂吸附法处理对硝基苯乙酮生产废水

采用AM-1吸附树脂和ND-900络合树脂对硝基苯乙酮生产废水进行吸附处理，试验结果表明，使用2种树脂串联的处理效果优于单独使用某一种树脂，而且ND-900络合树脂在前，AM-1吸附树脂在后串联处理的效果最好，废水体积为30BV时，COD去除率为92.8%；脱色率为100%，出水由原废水的橙红色变为无色，采用质量分数为8%的NaOH溶液作为脱附剂，脱附效果良好。