有机溶剂浸取石油污染土壤中的多环芳烃

采用索氏提取法和气相色谱分析了某炼油厂周边土壤中的多环芳烃的种类及含量,考察了6种有机溶剂对土壤中多环芳烃的浸取效果,探讨了溶剂与溶质溶解度参数差异对浸取效果的影响。结果表明：土壤试样中含有蒽、荧蒽、芘、 、苯并[a]蒽、苯并[b]荧蒽、苯并[k]荧蒽和苯并[a]芘8种多环芳烃,其含量分别为4.20,22.05,10.62,4.26,5.54,0.80,0.94,4.18 mg/kg;筛选出二氯甲烷作为土壤中多环芳烃的浸取溶剂;最佳浸取条件为浸取时间10 min、浸取温度30 ℃、溶剂与土壤的液固比5:1（mL/g）、土壤含水量8%,在此条件下,总多环芳烃浸出率为83.0%,各种多环芳烃的浸出率分别为蒽97.8%、荧蒽78.2%、芘99.9%、 98.5%、苯并[a]蒽81.1%、苯并[b]荧蒽47.6%、苯并[k]荧蒽14.8%、苯并[a]芘58.7%。     

煤矸石中元素Ba、Ni、Sr的淋溶析出

对安徽淮南煤矸石进行了成分分析和淋溶析出实验研究,结果表明：微量元素Ba、Ni、Sr在矸石山底部的含量高于新鲜样品,由此得出这三种元素对周围土壤及水环境的影响可能是有限的。     

Solubility and Potential Mobility of Heavy Metals in Two Contaminated Urban Soils from Stockholm,Sweden

The solubility and potential mobility of heavy metals (Cd, Cu,Hg, Pb and Zn) in two urban soils were studied by sequential andleaching extractions (rainwater). Compared to rural (arable) soils on similar parent material, the urban soils were highlycontaminated with Hg and Pb and to a lesser extent also with Cd,Cu and Zn. Metal concentrations in rainwater leachates were related to sequential extractions and metal levels reported fromStockholm groundwater. Cadmium and Zn in the soils were mainly recovered in easily extractable fractions, whereas Cu and Pb were complex bound. Concentrations of Pb in the residual fractionwere between two- and eightfold those in arable soils, indicatingthat the sequential extraction scheme did not reflect the solidphases affected by anthropogenic inputs. Cadmium and Zn conc. inthe rainwater leachates were within the range detected in Stockholm groundwater, while Cu and Pb conc. were higher, whichsuggests that Cu and Pb released from the surface soil were immobilised in deeper soil layers. In a soil highly contaminatedwith Hg, the Hg conc. in the leachate was above the median concentration, but still 50 times lower than the max concentration found in groundwater, indicating the possibilityof other sources. In conclusion, it proved difficult to quantitatively predict the mobility of metals in soils by sequential extractions.     

7种拟除虫菊酯农药对卤虫的急性毒性研究

为了研究7种拟除虫菊酯农药对美国大盐湖卤虫(GSL Artemia)的急性毒性效应,挑选18~24 h内孵出的卤虫,继续培养24 h后得到Ⅱ~Ⅲ龄卤虫无节幼体,将其暴露于所设浓度梯度的拟除虫菊酯溶液中进行24 h急性毒性实验,记录卤虫无节幼体在各浓度溶液中的死亡情况,并将所得数据进行Probit分析。结果表明,卤虫对不同拟除虫菊酯的敏感性相差较大。氯菊酯、氯烯炔菊酯、炔咪菊酯、胺菊酯、联苯菊酯、高效氯氟氰菊酯和溴氰菊酯对卤虫的24 h半致死浓度(24 h-LC50)分别为4.68、14.82、18.12、38.21、>100、>100和>100 mg.L-1。因此,在含有卤虫的盐水环境中,应尽量避免使用毒性较高的氯菊酯,而选择使用联苯菊酯、高效氯氟氰菊酯和溴氰菊酯等毒性较低的农药。     

Zinc recovery from hazardous construction wastes via an integrated process of the air classification,alkaline leaching,and water washing

Zinc- and lead-containing wastes are often mixed with construction and demolition wastes in many factories, generating abundant of heavy metal-enriched hazardous waste. In the present study, a novel integrated process of air classification, alkaline leaching, and water washing dechlorination was proposed for the efficient recycling of Zinc (Zn) resources. The first air classification process was realized via venturi tube, wherein the content of Zn could increase by 20 wt.%. After that, the product underwent an alkaline leaching process. Results showed that Zn recovery rate increased with fine particle sizes, and a 65% recovery rate was obtained under the following conditions of 5 mol/L NaOH, liquid/solid 10:1, and leaching time 1 h. Finally, water washing associated with microwave and ultrasonic treatments could remove over 85% of Cl and other water-soluble salts. All the results indicated that the integrated method had an excellent recovery rate for Zn resources from construction and demolition wastes.     

医疗焚烧废渣的固定化试验研究

医疗垃圾属于国家规定的危险废物,焚烧后的残渣同样存在最后稳定化的问题,国外处理方法主要是填埋和基础回填,本文通过对两种胶凝材料(普硅水泥和复合矿渣水泥)对医疗废渣的固定化效果研究,探讨医疗废渣再利用的可行性和影响因素。     

澳门城市垃圾焚烧底灰的重金属淋溶及其遗传毒性评价

应用美国国家环境保护局推荐的毒性特性溶出程序(toxicitycharacteristicleachingprocedure,TCLP),以及ICP-MS和ICP-AES技术研究了澳门城市垃圾焚烧底灰中重金属的淋溶,并结合蚕豆根尖微核试验评价了其潜在的生态与健康风险.结果显示,该底灰淋溶出来的重金属元素:铝(Al)、锰(Mn)、钴(Co)和汞(Hg)的浓度低于0.01mg·L-1,铁(Fe)、铜(Cu)和钼(Mo)的浓度低于0.1mg·L-1,而铬(Cr)、锌(Zn)、硒(Se)、锶(Sr)、钡(Ba)和铯(Cs)的浓度在0.11mg·L-1￣2.19mg·L-1之间.需要注意的是淋溶液中铅(Pb)的浓度异常高,最高可达19.06mg·L-1,超过了美国相关标准的上限(5mg·L-1);对比不同条件下底灰中重金属的淋溶情况,表明溶解作用和淋溶液的pH值是影响其淋溶的2个重要因素.蚕豆根尖微核试验显示各淋溶液处理组根尖细胞微核率明显升高,与阴性对照组相比具有显著性差异(p<0.05),表明各淋溶液具有遗传毒性;随着淋溶液中重金属浓度的增加,蚕豆根尖细胞所表现出来的毒性效应增强,表明重金属是淋溶液具有遗传毒性的重要原因.     

煤矸石在新型动态循环淋溶装置中的淋溶特性

采用新型循环淋溶装置对煤矸石进行连续240h的淋溶实验,研究了煤矸石中重金属在淋溶过程中的溶出规律,通过向淋溶液中添加聚丙烯酰胺（CPAM）考察了固体颗粒物的沉降特性.结果表明： 随着淋溶反应时间延长,煤矸石中碱金属Na元素溶于水,形成碱性溶液,这两种因素导致淋溶反应初期淋溶液pH值升高.As、Zn离子浓度在淋溶时间为1~24h时呈上升趋势,而在24~72h,离子浓度呈下降趋势.淋溶液中Cr、Pb、Ba离子浓度在120h内均呈现上升趋势,而在120~240h,对于Cr离子来说,淋溶液的碱性环境促使Cr离子溶出率增大,但取样次数的增多也对Cr离子的浓度降低起到促进作用;淋溶液稀释和Ba离子的沉淀化合物形成,导致淋溶液中Ba离子浓度降低.120~240h,淋溶液中有机物被微生物的生化作用分解以及取样后外加塌陷区水体对淋溶液中COD和BOD起到稀释作用,使COD和BOD降低.在淋溶反应24h内,淋溶液中TON和NH₃-N出现波浪式变化,淋溶时间大于24h时,TON和NH₃-N总体呈升高趋势.随着淋溶时间延长,淋溶液中的固体颗粒物沉降速度逐渐变慢,延长了沉降时间.煤矸石中一些含氮化合物溶解于水中,使淋溶液中电离出 NH₄⁺离子,形成碱性环境.     

Characteristics of the stabilized/solidified municipal solid wastes incineration fly ash and the leaching behavior of Cr and Pb

Fly ash is a hazardous byproduct of municipal solid wastes incineration (MSWI). An alkali activated blast furnace slag-based cementitious material was used to stabilize/solidify the fly ash at experimental level. The characteristics of the stabilized/solidified fly ash, including metal leachability, mineralogical characteristics and the distributions of metals in matrices, were tested by toxic characteristic leaching procedure (TCLP), X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) respectively. Continuous acid extraction was utilized to extract metal ions and characterize their leaching behavior. The stabilization/solidification procedure for MSWI fly ash demonstrates a strong fixing capacity for the metals by the formation of C-S-H phase, hydrated calcium aluminosilicate and ettringite. The stabilized/solidified fly ash shows a dense and homogeneous microstructure. Cr is mainly solidified in hydrated calcium aluminosilicate, C-S-H and ettringite phase through physical encapsulation, precipitation, adsorption or substitution mechanisms, and Pb is mainly solidified in C-S-H phase and absorbed in the Si-O structure.     

生物炭对菜地土壤氮平衡及酸碱缓冲能力的影响

针对太湖地区菜地化肥氮投入量较大导致氮淋失严重及土壤酸化的现状,选取太湖地区的菜地土壤,利用盆栽试验连续种植三季小白菜,结合生物炭埋袋回收技术,研究不同化肥氮施用量(以N计,0和110 mg/kg)及生物炭添加量(w为0%、1%、2%和5%)对土壤氮淋失及酸碱缓冲能力的影响. 结果表明:在化肥氮施用量为110 mg/kg条件下,与无生物炭添加相比,生物炭添加量为2%时可使作物对土壤矿质态氮的利用效率提高约1倍(由41%增至81%),因化肥氮施用引起的土壤氮素残留量降低83%;生物炭添加可有效减少48%~65%的土壤氮淋失量,当添加量为1%、2%时,生物炭主要通过削减淋失液中ρ(TN)来降低土壤氮淋失量;添加量为5%时,则主要通过削减淋失液体积来实现. 无论是否添加化肥氮,生物炭均能有效维持土壤原有的pH、w(有机质)及w(盐基离子);促使土壤酸碱缓冲能容量增加22%~37%,致酸速率降低17%~80%,显著提升了土壤的酸碱缓冲能力. 研究显示,在化肥氮施用量为110 mg/kg条件下,生物炭添加量为2%时能对土壤酸化产生较好的缓冲效果.