Effects of nanopesticide chlorfenapyr on mice

The effects of chlorfenapyr nano preparation on mice were examined. The animals were administered with different doses of 4.84, 9.68, or 19.36?mg?kg^?1 of chlorfenapyr common preparation or nano preparation intraperitoneally (IP). Micronucleus (MN) test and comet assay (CA) experiments revealed that at the same dose, similar DNA damage in the peripheral blood lymphocytes of the mouse and chromosome damage in bone marrow cells of the mouse occurred with chlorfenapyr nano preparation; however, the severity of these effects was less than that found in common preparation. It is noteworthy that there were no differences in apoptotic ratio and live cell percentage in the liver cells of the mouse between these two pesticide formulations using flow cytometry. Data indicate that chlorfenapyr nanoformulation is less toxic to mouse cells than the common formulation.     

Anatomy of an urban waterbody: a case study of Boston's Muddy River

The objective of this study was to characterize and understand the water quality of Boston's Muddy River prior to restoration, to help guide those activities and evaluate their success. We use a combination of monitoring, data analysis and mathematical modeling. The seasonal pattern of temperature, pollutant signatures (identified using a principal component analysis), correlations with precipitation and spatial patterns all point to a significant wastewater input at one of the outfalls and suggest significant receiving water impact. However, a quantitative analysis using a mathematical model (QUAL2K) suggests this source is not significant. Rather, internal loading from algae, sediment bed and waterfowl dominate the spatial pattern of water quality. These results suggest significant improvement can be expected from planned sediment dredging. The paper provides a case study of water quality assessment in the context of urban river restoration, and it illustrates the utility of combining monitoring and data analysis with modeling.     

Spatial and seasonal variations of polycyclic aromatic hydrocarbons in Haihe Plain, China

A dynamic fugacity model was developed to simulate the spatial and seasonal variations of PAHs in Haihe Plain, China. The calculated and measured concentrations exhibited good consistency in magnitude with deviations within a factor of 4 in air and 2 in soil. The spatial distributions of PAHs in air were mainly controlled by emission while the seasonal variations were dominated by emission and gas-particle partition. In soil, the spatial distributions of PAHs were controlled by the soil organic carbon content while the seasonal variations were insignificant. The severest soil contamination was observed in Shanxi and followed by the southwest of Hebei province. Transfer fluxes of total PAHs between air and soil were calculated. The spatial distribution of air-to-soil flux was closely related to the landcover while the soil-to-air flux changed with soil organic matter content. Monte Carlo simulation was done to evaluate the uncertainty of the estimated results in air.     

泡沫活性炭的制备及其对丙酮的吸附性能研究

以中间相沥青和原煤为原料,在高温高压下发泡成型,经过高温炭化和水蒸气活化后制得了比表面积为672m2/g、中孔发达的泡沫状成型活性炭(MACFoam).该成型活性炭中含有大量的微米级孔道并具有良好的透气性,可以作为气流通道.由其所装填的吸附床层对丙酮的吸附行为与颗粒活性炭相似,可以使用Yoon-Nelson方程对实验穿...     

海带对镉的吸附动力学与热力学研究

采用批量平衡法研究了海带对镉的吸附的动力学与热力学,并采用Lagrange假一级动力学方程、假二级动力学方程、Langmuir等温线方程、Freundlich等温线方程以及Dubimim-Radushkevich等温线方程对实验数据进行了拟合.结果表明,在4种温度下海带对镉的吸附率均随吸附反应时间增加而增大,在60 min时达到最大,此后基本保持不变,随着温度由20℃升高至50℃,其最大吸附率呈下降趋势,由90.2%降至77.5%;海带对镉的吸附动力学符合Lagrange假二级动力学方程;海带对镉的吸附热力学符合Langmuir等温线方程和Dubimim-Radushkevich等温线方程,表明吸附主要发生在海带表面的活性区位,属于单分子层吸附,其吸附平均活化自由能E为11.4 kJ/mol,表明该吸附过程为化学吸附,在4种温度下吉布斯自由能变化量△AG°均为负值,吸附焓变△H°也为负值,表明海带对镉的吸附为放热反应,能自发进行.     

pH值控制MAP法脱氮进程的可行性研究

MAP沉淀法处理高NH₃-N废水,操作简便,处理效果好。本试验以NH₃-N浓度为1 000 mg/L的模拟废水为研究对象,研究结果表明,在Mg²⁺∶PO^3-₄∶NH⁺₄=1.2∶1.2∶1（摩尔比）、NaOH投加量为675 g/L的条件下NH₃-N去除率高达98%以上。试验选择出水pH作为控制反应进程的参数,并建立了出水pH与NH₃-N去除率之间的关系。通过调整NaOH投加量控制出水pH在7.5～8之间时,NH₃-N去除率最高,可达98%以上。X-衍射图谱及定量分析表明,沉淀物中MAP的纯度较高,具有一定的回收价值。     

优化循环冷却水系统技术经济分析模型研究

应用系统分析方法以及最优化技术研究循环冷却水系统,分析了系统内部水量、水质等条件与系统运行费用之间的关系,运用技术经济的方法建立了循环冷却水的数学模型,通过判定最佳循环冷却水浓缩倍数确定系统的最优化结果,使循环冷却水系统的设计和运行管理更为科学合理.     

The influence of sodium on biohydrogen production from food waste by anaerobic fermentation

Anaerobic fermentation of food waste for hydrogen production was performed in serum bottles with various linear alkylbenzene sulfonate (LAS) dosages (7.1–21.4 g/l) and sodium concentrations (5.03–28.7 g/l). LAS can effectively inhibit the activity of hydrogen-consuming bacteria, and the maximum hydrogen yield of 109.2 ml/g volatile solid (VS) was obtained at an LAS dosage of 14.3 g/l without added sodium. The feasible pH for hydrogen production is 5.0–6.0, and the process will slow down or stop when the pH is below 5.0.The hydrogen production potential increased when the sodium concentration increased in the range 5.03–14.41 g/l. The maximum hydrogen yield was 154.8 ml/g VS, and then the hydrogen production began to decrease when the sodium concentration increased further. A sodium chloride concentration of 20 g/l and higher will enhance the osmotic pressure and make bacteria inert. In the effluent, acetic acid is the major by-product. The results indicated that the hydrogen production from the anaerobic fermentation of food waste could clearly be increased with the additives and a sodium concentration less than 20 g/l.