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141.
为了提高室内环境空气质量,本论文开展了光催化剂制备的研究。本论文采用溶胶-凝胶法制备B/Y^3+共掺杂TiO2复合光催化材料,以甲醛为降解物质,在紫外和可见光下分别研究了复合催化剂的光催化活性,对不同掺杂对光催化活性的影响、光催化剂的稳定性进行了分析。B/Y^3+共掺杂TiO2复合光催化材料大大提高了催化剂的活性,对甲醛降解有较高的效率。 相似文献
142.
广西河池铅锑矿冶炼区土壤中锑等重金属的分布特征及影响因素分析 总被引:6,自引:0,他引:6
对广西河池铅锑矿冶炼区土壤重金属污染特征进行了研究。结果表明:冶炼区土壤受到较高含量的Sb、Pb污染,As、Zn和Cu也有一定程度的污染。土壤中的w(Sb)和W(As)分别为155~30439mg/kg和27~17611mg/kg。冶炼区土壤中的重金属元素的含量与距离冶炼厂的距离有密切关系,不同重金属的衰减呈现不同的特点。研究区内三种不同类型土壤中的重金属元素呈现不同的分布特征:三种不同土壤类型Pb、As、Cu、Sb的含量关系为:水稻田>菜地>荒地。元素相关性分析表明Sb、Pb、As、Cu、Cd为密切相关的一组元素,可判定它们都与冶炼厂排放密切相关。 相似文献
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老化是影响土壤重金属生物可利用性和毒性的重要因素。为了解老化对土壤Sb形态和毒性的影响,结合化学分析和生物测试,以模式生物跳虫(Folsomia candida)为受试生物,研究了北京潮土中外源Sb(Ⅲ)分别老化7 d、60 d后价态、水溶态和急性/慢性毒性的变化。结果表明,老化仅7 d后,土壤较低浓度的Sb主要以Sb(Ⅴ)存在,而浓度较高(1 600、2 400、4 800 mg·kg-1)时Sb(Ⅴ)分别仅占47.4%、27.5%和2.2%,但老化长达60 d后,浓度最高(4 800 mg·kg-1)的土壤中Sb(Ⅴ)的比重上升到38.1%,其他浓度处理的土壤中,均以Sb(Ⅴ)为主。随着老化时间的延长,土壤中水溶态Sb含量占总Sb的比例显著降低。与土壤老化过程中毒性较大的Sb(Ⅲ)向毒性较小的Sb(Ⅴ)转化与水溶态Sb含量下降相一致,Sb对跳虫的毒性随老化时间的延长明显减弱:7 d老化后土壤Sb对跳虫急性存活的半数致死浓度(LC50)为2 105 mg·kg-1,对跳虫慢性存活的LC50为683 mg·kg-1,对跳虫繁殖的半数效应浓度(EC50)为307 mg·kg-1;老化60 d后土壤Sb对跳虫急性存活、慢性存活的LC50均大于设置的最高浓度,对跳虫繁殖的EC50为1 419 mg·kg-1。因此,对于Sb这种变价金属而言,当进行土壤Sb生态毒性评价时,为避免高估其生态风险,考虑老化作用显得尤为重要。 相似文献
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Dimitris Dermatas Xinde Cao Valentina Tsaneva Gang Shen Dennis G. Grubb 《Water, Air, & Soil Pollution: Focus》2006,6(1-2):143-155
This study investigates the fate and behavior of lead (Pb), copper (Cu), antimony (Sb), and arsenic (As) in a shooting range
soil. The soil samples were collected from the surface (0–15 cm) and the subsurface (15–40 cm and 40–55 cm) of a grassy and
wood chip covered impact area behind a firing position. Optical microscopy images indicate significant amounts of corroded
bullet fragments and organic wood chips in the surface soil. Analysis by X-ray powder diffraction (XRPD) and scanning electron
microscopy electron dispersive X-ray spectroscopy (SEM-EDS) showed that metallic Pb was transformed into lead oxides (litharge
PbO and massicot PbO) and lead carbonates (hydrocerussite Pb3(CO3)2(OH)2, cerussite PbCO3, and plumbonacrite Pb5(CO3)3O(OH)2). Rietveld quantification indicated the surface soil contained 14.1% metallic Pb, 17.9% hydrocerussite, 5.2% plumbonacrite,
5.9% litharge, and 3.9% massicot on a dry weight basis, or a total of 39.7% Pb, far in excess of lead concentrations typically
found in US shooting range soils. Metallic Cu (bullet jacket material) appeared stable as no secondary minerals were detected
in the surface soil. As and Sb concentrations were on the order of 1,057 mg/kg and 845 mg/kg respectively. The elevated soil
pH coupled with high organic carbon content is thought to have caused downward migration of metals, especially for Pb, since
4,153 mg Pb/kg was observed at a depth of 55 cm. More than 60% of Pb was concentrated in the coarse soil (> 0.425 mm) fraction,
suggesting soil clean-up possible by physical soil washing may be viable. The concentrations of Pb, As, and Sb in the toxicity
characteristic leaching procedure (TCLP) extracts were 8,869 mg/L, 6.72 mg/L, and 6.42 mg/L respectively, were above the USEPA
non-hazardous regulatory limit (As and Pb) of 5 mg/L. The elevated Sb and As concentrations draw concern because there is
historically limited information concerning these metals at firing ranges and several values exceeded local soil cleanup criteria.
As the high Pb concentrations appeared to be linked to the presence of organic-rich berm cover materials, the use of wood
chips as berm cover to prevent soil erosion requires reconsideration as a shooting range management practice. 相似文献
149.
通过静态试验方法研究了ZrO2 纳米颗粒液相吸附联苯胺的性能 ,结果表明 ,虽然联苯胺均可与ZrO2 纳米颗粒表面羟基及水分子形成氢键 ,但它与ZrO2 纳米颗粒表面羟基之间形成的氢键稍强 ,吸附去除效果较好 ,该吸附体系很好吻合Freundlich和deBoer Zwikker吸附等温式 ,热分析显示联苯胺与ZrO2 纳米颗粒表面之间的吸附成键作用较弱。 相似文献
150.
A solution culture experiment was designed to determine whether Si can alleviate Sb toxicity in rice. The design involved a rice mutant with low Si accumulation and wild-type rice with normal Si accumulation. The effects of Si on rice Sb stress in the presence or absence of P were investigated. P significantly increased the shoot biomass in both wild-type and mutant rice, whereas Si increased the biomass only in the wild-type rice. No biomass change was detected in both rice type when 10 or 30 μ mol·L?1Sb was added to the solution. Compared with the no P control, in both rice types, the application of 0.7 mmol·L?1 P significantly increased the P content, whereas Si significantly influenced the uptake and accumulation of P and Sb. In different P and Sb treatments, 1.0 mmol·L?1 Si led to 6.9–58.2% and 21.4–62.5% decreased Sb content in the shoots of wild-type and mutant rice, respectively. Si addition also significantly impacted the distribution coefficient of Sb between the shoots and seeds of both rice types. These results suggest that the application of Si in rice can promote growth, reduce Sb accumulation and decrease Sb movement to shoot and seeds, which may lead to Sb pollution control under rice field conditions. 相似文献