城市垃圾焚烧飞灰中Pb、Cd、Zn去除工艺研究

[目的]研究HCl和Na2EDTA对城市生活垃圾焚烧飞灰中Pb、Cd和Zn的浸洗效果及工艺.[方法]针对海口市生活垃圾焚烧飞灰,研究HCl和Na2EDTA两种不同浸洗剂对飞灰中重金属的浸洗效果,并对浸洗前后飞灰中重金属形态的变化进行了分析.[结果]HCl对3种重金属都有较好的浸洗效果,去除效果为Cd ＞Zn ＞Pb.Na2EDTA对Pb和Cd的浸洗效果较好,对Zn的去除率远低于其他2种重金属.HCl对飞灰浸洗的适宜条件:室温下浓度为0.8 mol/L,液固比为10,淋洗时间为180 min.Na2EDTA对飞灰浸洗的适宜条件:室温下浓度为0.05 mol/L,液固比为15,淋洗时间为360 min.浸洗后飞灰中3种重金属可交换态和碳酸盐结合态的比例减小,残渣态的比例显著增大,飞灰的稳定性增加.[结论]该研究可为飞灰的处理处置及资源化利用提供科学依据.     

Plant-Available Phosphorus after Application of Synthetic Chelating Agents

Fertilizer phosphorus (P) can become immobilized in acidic soils through bonds with iron (Fe) and aluminum (Al). Two chelating agents, ethylenediamine tetraacetic acid disodium salt (EDTA) and hydroxyethyl ethylenediamine triacetic acid (HEEDTA), were tested in a greenhouse study for efficiency at increasing plant-available P to corn (Zea mays L.). Fertilizer P was added with or without chelate to the center of pots, simulating a starter band of P. Without the presence of chelates, biomass above and below ground increased linearly as P fertilizer rates increased at 0, 9.6, 19.3, 28.9, and 38.5 kg P ha^?1. Applications of EDTA and HEEDTA did not significantly increase water-soluble P (WSP), Mehlich 1 P, and Mehlich 3 P compared to soils without chelates. Applications of EDTA increased P uptake in the belowground biomass. Despite previous research showing that chelates increased WSP in soils, a decrease in P sorption was not observed with the additions of chelating agents to soils.     

含海藻糖稀释剂增补EDTA对猪精子冷冻能力的影响

探讨了猪精子冷冻保存液中添加不同浓度的海藻糖(trehalose)和EDTA(0.05mol/L trehalose、0.05mol/L trehalose 2.0mmol/LEDTA、0.05mol/L trehalose 5.0mmol/L EDTA、0.1mol/L trehalose、0.1mol/L tre-halose 2.0mmol/LEDTA、0.1mol/L trehalose 5.0mmol/LEDTA)对猪精子冷冻效果的影响。结果表明,精子冷冻解冻后,0.1mol/Ltrehalose 2mmol/LEDTA混合处理组精子活力显著高于0.1mol/Ltrehalose处理组(P<0.05),0.1mol/Ltrehalose和5.0mmol/LEDTA混合处理组的精子生存率最高。0.1mol/Ltrehalose和2~5mmol/LEDTA混合处理组精子顶体完整率显著高于trehalose处理组(P<0.05),0.05~0.1mol/Ltrehalose和5.0mmol/LEDTA混合处理组低渗膨胀精子率显著高于trehalose处理组(P<0.05)。trehalose和EDTA混合处理组精子内活性氧(ROS)含量总体上高于trehalose处理组(P<0.05)。这些结果显示稀释剂中trehalose和EDTA增补能改善精液特性,但不能抑制精子内ROS的发生。     

Effects of Chelating Compounds on Mobilization and Phytoextraction of Copper and Lead in Contaminated Soils

Six chelating compounds: ethylenediamine-tetraacetic acid (EDTA), ethylenediamine-N, N'-disuccinic acid (EDDS), tartaric acid, citric acid, glycine and histidine, were tested as potential agents to mobilize copper (Cu) and lead (Pb) from two soils polluted with the emissions from copper smelters. Copper was mobilized with the following efficiency: EDTA > citric and tartaric acids > histidine > EDDS and glycine, while Pb extractability followed the order: EDTA > EDDS >> tartaric and citric acid >> glycine and histidine. With respect to these results, EDTA and EDDS were chosen for a pot experiment on chelate-induced phytoextraction of Cu and Pb by maize (Zea mays). Chelates were applied at the rates of 0.2, 0.5, and 1.0 mmol kg^?1, and this experiment was carried out at two different watering regimes. Both EDTA and EDDS caused significant increase of Cu uptake from soils, but its concentrations in biomass were far below those required for efficient soil remediation. Lead uptake was only slightly affected by chelate application. Losses of Cu from soil by leaching were much higher than those caused by plant uptake.     

修复剂对镉污染盐渍化土壤植物修复效率的影响

目前,重金属污染盐渍化土壤已成为世界性的环境问题,利用盐生植物进行修复具有良好的环境与经济效益,但如何提高盐生植物修复效率的研究尚较少.采用盆栽试验方法,通过向土壤中施加氯化钠和氯化镉溶液分别模拟无污染非盐渍化土壤(Cd0S0)、NaCl型盐渍化土壤(Cd0S4)、重金属Cd污染土壤(Cd3S0)、重金属Cd污染NaC...