The effects of different electrode materials on seed germination of Solanum nigrum L. and its Cd accumulation in soil

The effects of different electrode on Solanum nigrum L.seed germination were determined.The result showe d that germination percentage(GP) of seeds in treatment T2(titanium electrode) was 26.6% higher than in control(CK,without electric field).High potassium and calcium concentrations were beneficial for seed enzymatic activity in treatment T2,which could partly explain the increase in GP.Cd accumulation(μg/pot) in S.nigrum treated with any electric field was significantly higher(p<0.05) than...     

Pyrolysis characteristics of the mixture of printed circuit board scraps and coal powder

Thermogravimetric (TG) analysis and infrared spectroscopy were used to analyze the pyrolysis characteristics of printed circuit board scraps (PCBs), coal powder and their mixtures under nitrogen atmosphere. The experimental results show that there is a large difference between waste PCBs and coal powder in pyrolysis processing. The pyrolysis properties of the mixing samples are the result of interaction of the PCBs and coal powder, which is influenced by the content of mixture. The degree of pyrolysis and pyrolysis properties of the mixture are much better than that of the single component. The TG and the differential thermogravimetric (DTG) curves of the PCBs mixed with coal powder move towards the high-temperature zone with increasing amount of coal powder and subsequently the DTG peak also becomes wider. The Coats–Redfern integral method was used to determine the kinetic parameters of pyrolysis reaction mechanism with the different proportion of mixture. The gas of pyrolysis mainly composes of CO₂, CO, H₂O and some hydrocarbon. The bromide characteristic absorption peak has been detected obviously in the pyrolysis gas of PCBs. On the contrary, the absorption peak of the bromide is not obvious in pyrolysis gas of the PCBs samples adding 40% coal powder.     

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. Translated from Environmental Science, 2007, 28(6) [译自: 环境科学]     

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.     

整体式催化剂选择性催化氧化硫化氢

在堇青石蜂窝陶瓷基体上分两步涂覆了SiO₂和TiO₂两种涂层,再通过浸渍法制备了V₂O₅/TiO₂-SiO₂/堇青石整体式催化剂。采用BET、XRD、XRF、SEM和H₂-TPR等方法对催化剂进行了表征,并对催化剂的H₂S选择性催化氧化活性进行了评价。结果表明：V₂O₅负载量为20%（w）时,催化剂的活性最好;在反应温度180 ℃、空速3 000 h^-1、V（O₂）∶V（H₂S）=0.5的条件下,转化率达96.94%,硫产率达95.41%。在40 h的稳定性试验过程中,转化率稳定在96%左右,硫产率稳定在94%左右,催化剂的稳定性较好。与传统颗粒状催化剂相比,该整体式催化剂更具工业应用前景。     

Lead accumulation in different Chinese cabbage cultivars and screening for pollution-safe cultivars

Recently, the concept of pollution-safe cultivars (PSCs) was proposed to minimize the influx of pollutants to the human food chain. Variations in lead (Pb) uptake and translocation among Chinese cabbage (Brassica pekinensis L.) cultivars were investigated in a pot-culture experiment and a field-culture experiment to screen out Pb-PSCs for food safety. The results of the pot-culture experiment showed that shoot Pb concentrations under two Pb treatments (500 and 1500 mg kg^?1) varied significantly (p < 0.05) between cultivars, with average values of 3.01 and 6.87 mg kg^?1, respectively. Enrichment factors (EFs) and translocation factors (TFs) in cultivars were less than 0.50 and varied significantly (p < 0.05) between cultivars. Shoot Pb concentrations in 12 cultivars under treatment T₁ (500 mg kg^?1) were lower than 2.0 mg kg^?1. The field-culture experiment further confirmed Qiuao, Shiboqiukang and Fuxing 80 as Pb-PSCs, which were suitable to be cultivated in low-Pb (<382.25 mg kg^?1) contaminated soils and harmless to human health as foods.     

镉中毒的干预措施与机理分析

镉极易在人体内蓄积且自然排泄缓慢,对人体健康危害严重,因此关于镉毒性的干预措施及机理研究意义重大。系统总结了螯合剂、金属硫蛋白、营养元素(锌、硒、钙、铁和维生素等),以及中药对镉毒性的干预作用及其机理。目前,镉中毒的许多干预措施均是利用与镉具有更高亲和性的一些外加物质,在动物体内与镉形成易于排出体外的复合物,再通过动物正常的生理活动将镉排出,以消除镉对机体内一些必需元素的正常新陈代谢活动的干扰。中药对镉中毒的干预机理可能成为新的研究热点。     

碱性条件下胡敏酸吸附镉的特征研究

为了探讨胡敏酸在碱性条件下的吸附镉机理,了解碱性盐化土壤中镉污染机理和生态环境之间的关系,实验研究了胡敏酸在碱性条件吸附镉的特征。采用批吸附试验方法,研究不同Cd初始浓度、反应时间、不同pH和离子强度对胡敏酸吸附镉的影响,结果表明：胡敏酸具有较强吸附镉的能力,可以用Langmuir吸附模型和Temkin吸附模型很好地拟合其等温吸附过程（r分别为0.9809和0.9816）;在60 min内的快速反应阶段和60 min至6 h间的慢速反应阶段,胡敏酸对镉的吸附量分别为2.895 mg·g-1和3.342 mg·g-1,吸附反应平衡前6 h的动力学过程可以用Elovich方程进行很好的拟合（r为0.9285）;随着pH增加,吸附率表现出逐步增加趋势,并以pH为4.5和8.5为界,呈现两端增加速度快,中间增加慢的规律性;在较低浓度离子强度下,离子强度的增加促进胡敏酸吸附镉;而在高离子强度下,表现出相反的规律性;在相同的条件下,不同离子强度对胡敏酸吸附镉的影响大小为：氯化钙〉氯化镁〉氯化钾〉氯化钠。土壤在盐化的过程中,由于无机盐浓度的增加,增加了重金属离子的生物可利用性,加大了重金属离子的生态风险。     

Effects of different soil pH and nitrogen fertilizers on Bidens pilosa L. Cd accumulation

Environmental Science and Pollution Research - Bidens pilosa L. was a Cd hyperaccumulator. This experiment determined the effects of different soil pH (adjusted by weak acid and alkali at 4.83,...