新疆三地区总悬浮颗粒(TSP)中单颗粒的微观形貌特征

用扫描电镜/X射线衍射能谱(SEM/EDX)对喀什地区、乌鲁木齐市米东区、和田地区的总悬浮颗粒(TSP)的单个颗粒进行了形貌观察。经分析得出:喀什地区颗粒物无规则形为34%,片状为54%;和田地区的颗粒物片状为80%,球形为12%;乌鲁木齐市米东区的颗粒物均匀球形蜂窝聚集态为90%。对此作来源解析可以认为:乌鲁木齐市米东区的TSP主要来源是燃烧排放的飞灰及在大气中形成的二次粒子居多,而喀什地区及和田地区的TSP主要来源为土壤及矿物颗粒灰尘。     

Emission and Performance Characteristics of a 2 Litre Toyota Diesel Van Operating on Esterified Waste Cooking Oil and Mineral Diesel Fuel

Exhaust emission and performance characteristics were evaluated in a Toyota van, powered by a 21 indirect injection (IDI) naturally aspirated diesel engine, operating on vegetable based waste cooking oil methyl ester (WCOME).Tests were performed on a chassis dynamometer and the data were compared with previous results conducted on the same vehicle using mineral diesel fuel. The data obtained includes smoke opacity, carbon monoxide (CO), carbon dioxide (CO₂), oxygen (O₂), nitrogen dioxide (NO₂), nitric oxide (NO), sulfur dioxide (SO₂) and brake power. Engine lubricating oil samples were also taken. Results from this study indicated a difference of approximately 9% in brake power between the two fuels. WCOME developed a significant lower smoke opacity level and reduced CO, CO₂, SO₂ emissions. However, O₂, NO₂ and NO levels were higher with the vegetable oil based fuel. Power values were comparable for both fuels. Lubricating oil analysis gave little change of viscosity and wear metal concentrations after 2887km were: Silicon 35ppm, Chromium 3.3ppm, Iron 33.8ppm, Copper 14.1ppm and lead 78.6ppm.     

Adsorption-desorption and leaching of pyraclostrobin in Indian soils

Pyraclostrobin is a new broad-spectrum foliar applied and seed protectant fungicide of the strobilurin group. In this paper, adsorption-desorption of pyraclostrobin has been investigated in three different soils viz. Inceptisol (sandy loam, Delhi), Vertisol (sandy clay, Hyderabad) and Ultisol (sandy clay loam, Thrissur). Effect of organic matter and clay content on sorption was also studied in Inceptisol of Delhi. Leaching potential of pyraclostrobin as influenced by rainfall was studied in intact soil columns to confirm the results of adsorption-desorption studies. The adsorption studies were carried out at initial concentrations of 0.05, 0.1, 0.5, 1 and 1.5 μg mL^?1. The distribution coefficient (K_d) values in three test soils ranged from 4.91 to 18.26 indicating moderate to high adsorption. Among the three test soils, adsorption was the highest in Ultisol (K_d 18.26), followed by Vertisol (K_d 9.87) and Inceptisol (K_d 4.91). K_F value was also highest for Ultisol soil (66.21), followed by Vertisol (40.88) and Inceptisol (8.59). S-type adsorption isotherms were observed in all the three test soils. K_d values in organic carbon-removed soil and clay-removed soil were 3.57 and 2.83 respectively, indicating lower adsorption than normal Inceptisol. Desorption studies were carried out at initial concentrations of 0.5, 1 and 1.5 μg mL^?1. Desorption was the greatest in Inceptisol, followed by Vertisol and Ultisol. Amounts of pyraclostrobin desorbed in three desorption cycles for different concentrations were 23.1–25.3%, 9.4–20.7% and 8.1–13.6% in Inceptisol, Vertisol and Ultisol respectively. Desorption was higher in clay fraction-removed and organic carbonremoved soils than normal Inceptisol. Desorption was slower than adsorption in all the test soils, indicating hysteresis effect (with hysteresis coefficient values varying from 0.05 to 0.20). Low values of hysteresis coefficient suggest high hysteresis effect indicating easy and strong adsorption, and slow desorption, of pyraclostrobin in soils. Higher hysteresis coefficient values in organic carbon removed soil (0.25–0.30) and clay fraction removed soil (0.28–0.36) as compared to normal Inceptisol soil suggest relatively weak adsorption and easy desorption of pyraclostrobin. Results of regression analysis suggest that the organic matter and pH of the soil play a major role in adsorption of pyraclostrobin. Leaching studies were carried out in intact soil columns in Inceptisol. The columns were leached with different amounts of water simulating different amounts of rainfall. The results suggest that most of the pyraclostrobin residues will remain present in the top soil layers even under high rainfall conditions and chances of pyraclostrobin moving to lower soil depth are almost negligible.     

Controlled release and retarded leaching of pesticides by encapsulating in carboxymethyl chitosan /bentonite composite gel

A novel composite gel composed of carboxymethyl-chitosan (CM-chit) and bentonite (H-bent) was used as the carrier for encapsulating atrazine and imidacloprid to control their release in water and retard their leaching in soil. Strong interactions between CM-chit and H-bent in the composite were confirmed by FT-IR, and good dispersion of pesticides in the carrier was observed by SEM. According to the results of release experiments in water, the CM-chit/H-bent composite carrier showed double advantages of both encapsulation by the polymer and sorption by the bentonite. The time taken for 50 % of active ingredients to be released, t ₅₀, was prolonged to 572 h for atrazine and 24 h for imidacloprid, respectively. The difference between the two pesticides on release behavior was related to their hydrophobicity and water solubility. Leaching experiments through a soil layer showed that this novel carrier reduced the amount of pesticides available for leaching, and would be useful for diminishing the environmental pollution of pesticides.     

Dissipation of terbuthylazine,metolachlor, and mesotrione in soils with contrasting texture

ABSTRACT

This study evaluates the dissipation of terbuthylazine, metolachlor, and mesotrione at different depths in soils with contrasting texture. The field trial was conducted at the Padua University Experimental Farm, north-east Italy. The persistence of three herbicides was studied in three different soil textures (clay soil, sandy soil, and loamy soil) at two depths (0–5 and 5–15 cm). Soil organic carbon content was highest in the clay (1.10%) followed by loam (0.67%) and sandy soil (0.24%); the pH of soils was sub-alkaline. Terbuthylazine, metolachlor, and mesotrione were applied on maize as a formulated product (Lumax®) at a dose of 3.5 L ha^?1. Their dissipation in the treated plots was followed for 2 months after application. The concentrations of herbicides were analyzed by liquid chromatography-mass spectrometry. The dissipation of terbuthylazine, metolachlor, and mesotrione could be described by a pseudo first-order kinetics. Terbuthylazine showed the highest DT50, followed by metolachlor and mesotrione. Considering the tested soil, the highest DT50 value was found in clay soil for terbuthylazine and metolachlor, whereas for mesotrione there was no difference among soils. Significant differences were found between the two soil depths for terbuthylazine and metolachlor, whereas none were found for mesotrione. These results suggest that soil texture and depth have a strong influence on the dissipation of terbuthylazine and metolachlor, whereas no influence was observed on mesotrione because of its chemical and physical properties.     

凹凸棒粘土对水中亚甲蓝的吸附性能

用焦磷酸钠和盐酸纯化了地产凹凸棒粘土,SEM、XRD和FT-IR表征其结构。研究了凹凸棒粘土对亚甲蓝的吸附性能及热力学和动力学特征,考察了吸附时间、温度、初始浓度、pH和离子强度下对亚甲蓝吸附的影响。结果表明,不同实验条件下,吸附过程均符合准二级动力学特征。凹凸棒粘土对亚甲蓝是放热的物理吸附过程,吸附符合Langmuir模式,在303 K时最大吸附量为114.02 mg/g。与其他吸附材料相比,凹凸棒粘土对亚甲蓝有较快的吸附速率和较大的吸附量,可以作为价廉的吸附剂用于亚甲蓝的消除。     

铅锌矿尾矿制备陶粒处理选矿废水

以铅锌矿浮选尾矿为原料,水玻璃和木质素作为添加剂,通过高温焙烧,制备水处理陶粒,并用其对选矿废水进行了吸附处理实验研究。实验结果表明,在不添加任何添加剂的条件下,800℃左右烧制的陶粒对选矿废水的COD吸附效果较好,COD去除率达到87.1%;当木质素+水玻璃作为粘结剂烧制陶粒时,不仅陶粒散落减少,COD的去除率和吸附容量都有所增加,COD去除率达到了88.21%,从而达到了"以废治废"的目的。     

5种吸附剂对水中离子液体的吸附性能

实验研究了蒙脱土、活性白土、人造沸石、活性炭和水滑石5种吸附材料在25℃和50℃下对[Bmim]Cl的吸附过程,结果表明,蒙脱土对离子液体的去除效果最好,温度对活性炭的吸附有一定的影响,而对其他吸附剂的影响不大,说明这些无机矿物发生了离子交换型吸附过程。实验进一步研究了蒙脱土在25℃下对[Bmim]Cl、[Bmim]BF4、[Bmim]PF6、[Bmim]DBP、[Hmim]Cl和[Omim]Cl 6种离子液体的吸附行为,结果表明,对于阳离子相同的离子液体,阴离子对吸附影响不大;对于阴离子相同的离子液体,其饱和吸附量随着阳离子链长的增加而减小。     

基于矿产资源租的国内外矿产资源有偿使用制度比较

当前,我国矿产资源领域的制度建设相对滞后.西方市场经济国家经过多年建立起来的矿产资源有偿使用制度,对我国相关制度的建设具有借鉴意义.文章从稀缺租和李嘉图的级差地租的视角出发,对国内外矿产资源有偿使用制度的经济学基础进行了分析,指出了国内外各种矿产资源税费所代表的矿产资源租的含义.在此基础上,梳理出国内外矿产资源税费的对应关系,指出:①我国的资源税、矿产资源补偿费、矿区使用费相当于国外的权利金;②矿业权价款相当于国外的红利;③矿业权使用费相当于国外的矿业权出让金;④石油特别收益金相当于国外的资源租金税;⑤而对应于国外的资源耗竭补贴,我国还没有出台相应的税费.文章建议新的矿产资源有偿使用制度改革方案应达到两点,第一,理顺租、税、费之间的关系;第二,理顺对级差地租和稀缺租的征收,在新古典经济学的框架下,寻求一个对级差地租和稀缺租征收的最优水平,实现国家的资源所有权益,减小社会收入分配不公,补偿外部性和代际成本.     

多孔矿物载体厌氧固定床处理有机废水研究

通过天然浮石和塑料多孔空心球而制成复合式多孔矿物载体应用于厌氧固定床反应器中,研究反应器挂膜性能,以及处理生活污水、啤酒废水效果,应用扫描电镜观察生物膜微生物相的形态结构.结果表明,反应器挂膜69 d后COD去除率稳定在70%以上,初次启动成功;处理生活污水中平均COD去除率为61.72%;处理啤酒废水中COD去除率高...