船舶塑料垃圾热解特性及动力学分析

利用热重分析(TGA)研究船舶塑料垃圾在不同升温速率和不同气氛下的热解特性,并得到了热解动力学参数。结果表明,船舶塑料垃圾的热解过程主要有3个阶段,比一般塑料热解复杂;随着升温速率增大,最大热解速率和最大热解速率温度等热解特性参数也增大,反应变得更剧烈;N2/CO2比为4∶1时,热解反应进行得最完全,固体残留率最少。动力学分析表明,采用3个连续一级反应模型能很好地拟合实验数据;不同的升温速率和气氛比对反应各阶段活化能均有不同程度的影响。     

络合萃取技术分离制药废水中的金刚烷胺

以P204为络合剂萃取水溶液中的金刚烷胺,研究了正辛醇和煤油2种稀释剂对萃取效果的影响,分析了萃取过程的络合机理和热力学过程,并考察了该萃取体系对实际制药废水中金刚烷胺的萃取效果。结果表明,采用P204/正辛醇=3∶2的复配萃取剂,在初始pH为8.0,在油/水相比为1∶1的条件下,金刚烷胺的萃取效率可以达到99.8%以上;以2.0mol/L的HCl溶液为反萃取剂,可以将51.1%的负载金刚烷胺反萃回收;红外光谱分析表明,P204对金刚烷胺的萃取遵循离子交换和离子缔合成盐机制;萃取过程为放热过程,低温条件下有利于萃取反应的进行;P204/正辛醇复配萃取剂对实际制药废水中的金刚烷胺也具有很高的萃取效率。     

Alterations in the rabbit lymphoid tissue after bendiocarb administration

Various pesticides have immuno-suppressive effects, and thus the organisms become responsive to viral, bacterial and parasitic diseases and neoplasm. The aim of the study was to observe the structure of the small intestine (height of enterocytes and crypts), mucosal lymphoid tissue (Payer's patches, lymphocytes in lamina propria) and a lymph node after administration of bendiocarb (2,2-dimethyl-1,3-benzodioxol-4-yl-methylcarbamate) on days 3, 10, 20, 30 and 60 of the experiment. The height of the observed enterocytes showed an increasing tendency. On days 20, 30 and 60 we also observed an increase in diameter of crypts located in intestinal epithelium. The number of cells in lamina propria mucosae was significantly reduced on days 20 and 30 after administration of bendiocarb. Observations of the lymph node showed that on days 10 and 20 there was a significant increase in relative volume of medulla at the expense of the relative volume of the cortex and a decrease in the number of lymphocytes. However, we recorded an increase in diameter of lymphocytes. The intracellular parasite Toxoplasma gondii (T. gondii) belongs to the most common pathogenic parasites in the world and it can cause serious health complications in pregnant and immunodeficient individuals. DNA isolation, standard polymerase chain reaction (PCR) and visualization in a 2.5 % agarose gel, the presence of DNA T. gondii was detected in no examined rabbit brain samples. Using real time PCR T. gondii DNA was detected and quantified in the three rabbit brain samples (10 %).     

Mercury in European Blushers,Amanita rubescens,mushrooms and topsoils: Bioconcentration potential and intake assessment

Total mercury content has been determined in fruiting bodies of European Blushers and topsoils collected from 11 sites across Poland in 2006-2008. Mercury analysis was carried out using a validated analytical method and cold-vapour atomic absorption (CV-AAS). The European Blusher effectively accumulated mercury in fruiting bodies. The mean values of total mercury in caps of European Blushers from background (uncontaminated) areas were from 0.22 to 1.0 (0.067-3.2) and in stipes from 0.16 to 0.65 (0.071-2.7) μg/g dry weight. In topsoil beneath to fruiting bodies, the median Hg concentration at 10 sites in Northern Poland varied between 0.030 and 0.072 (0.0096–0.19) μg/g dw, and in one site in Southern Poland was 0.20 (0.079–0.34) μg/g dw. Data on Hg in European Blushers from different countries were reviewed. The mean concentrations of total Hg in caps of European Blushers from two “pristine” sites in northern part of Poland were ～1.0 μg/g dw. A meal made with 300–500 g of fresh caps of European Blushers collected at such sites (assuming 90% water content in caps) can result in Hg intake of 0.0003–0.0005 mg Hg/kg bm (assuming a 60 kg bm), which is a dose equipotent to a new provisional tolerable weekly intake (PTWI) value set for inorganic Hg.     

Biodegradation of beta-cypermethrin by a novel Azoarcus indigens strain HZ5

A novel strain HZ5 was isolated from the activated sludge of a pesticide manufacturer in Hangzhou, which was capable of degrading beta-cypermethrin (beta-CP). Based on its physiological characteristics and analysis of 16S rDNA gene, strain HZ5 was identified as Azoarcus indigens, which was a new genus that can degrade beta-CP effectively. Strain HZ5 could degrade beta-CP over a wide range of temperature (20 to 40°C) and pH (5.5 to 9.0), and the optimal temperature and pH were 30°C and 7.0. The highest degradation rate was approximately 70% of 50 mg/L beta-CP within 144 h at pH 7.0 and 30°C in MSM. An additional carbon source could enhance the biodegradation of beta-CP. Studies on biodegradation of the beta-CP showed no significant enantioselectivity. During the process, two main intermediate metabolites were produced by strain HZ5 and determined as 3-phenoxybenzaldehyde and 3-phenoxybenzoic acid by gas chromatography-mass spectrometry (GC-MS) analysis. The results indicated that strain HZ5 may have potential application in bioremediation of beta-CP polluted environment.     

The characteristics of nitrate removal by the psychrotolerant denitrifying bacterium Acinetobacter johnonii DBP-3, isolated from a low-temperature eutrophic body of water

A psychrotolerant denitrifying bacterial strain, DBP-3, was isolated from a eutrophic body of water by low-temperature-oriented acclimation culture. Based on its morphologicalandbiochemicalcharacteristics and 16S rDNA gene sequence, the bacterium was identified as belonging to the genus Acinetobacter and closely related to A. johnonii. The satisfactory growth of DBP-3 was observed at 10–30°C and pH 7–9. Strain DBP-3 was able to utilize three types of carbon sources (sodium acetate > sodium citrate > glucose) to support growth and denitrification. DBP-3 grew faster, but with lower nitrate removal efficiency and higher nitrite accumulation, under aerobic conditions than under anoxic conditions. DBP-3 was extremely susceptible to tetracycline and rifampicine and less sensitive to ampicillin and penicillin. The growth of DBP-3 was significantly affected by Hg (II), Cr (VI), Pb (II), Cd (II), and As (III) at 0.32, 0.63, 1.25, 2.5, and 25.0 mg L^?1, respectively. Interestingly, chromium (VI) significantly promoted DBP-3 growth at concentrations lower than 0.32 mg L^?1. These data may be helpful to support the use of strain DBP-3 in the purification of eutrophic water bodies at low temperatures.     

An Optimal Model and Its Application for the Management of Municipal Solid Waste from Regional Small Cities in China

Abstract

Based on the basic characteristics of municipal solid waste (MSW) from regional small cities in China, some optimal management principles have been put forward: regional optimization, long-term optimization, and integrated treatment/disposal optimization. According to these principles, an optimal MSW management model for regional small cities is developed and provides a useful method to manage MSW from regional small cities. A case study application of the optimal model is described and shows that the optimal management scenarios in the controlling region can be gained, adequately validating and accounting for the advantages of the optimal model.     

Inorganic Acid Emission Factors of Semiconductor Manufacturing Processes

Abstract

A huge amount of inorganic acids can be produced and emitted with waste gases from integrated circuit manufacturing processes such as cleaning and etching. Emission of inorganic acids from selected semiconductor factories was measured in this study. The sampling of the inorganic acids was based on the porous metal denuders, and samples were then analyzed by ion chromatography. The amount of chemical usage was adopted from the data that were reported to the Environmental Protection Bureau in Hsin-chu County according to the Taiwan Environmental Protection Agency regulation. The emission factor is defined as the emission rate (kg/month) divided by the amount of chemical usage (L/month). Emission factors of three inorganic acids (i.e., hydrofluoric acid [HF], hydrochloric acid [HQ], and sulfuric acid [H₂SO₄]) were estimated by the same method. The emission factors of HF and HCl were determined to be 0.0075 kg/L (coefficient of variation [CV] = 60.7%, n = 80) and 0.0096 kg/L (CV = 68.2%, n = 91), respectively. Linear regression equations are proposed to fit the data with correlation coefficient square (R²) = 0.82 and 0.9, respectively. The emission factor of H₂SO₄, which is in the droplet form, was determined to be 0.0016 kg/L (CV = 99.2%, n = 107), and its R² was 0.84. The emission profiles of gaseous inorganic acids show that HF is the dominant chemical in most of the fabricators.     

Absorption and Reaction Kinetics of Amines and Ammonia Solutions with Carbon Dioxide in Flue Gas

Abstract

The removal system for the absorption of CO₂ with amines and NH₃ is an advanced air pollution control device to reduce greenhouse gas emissions. Absorption of CO₂ by amines and NH₃ solutions was performed in this study to derive the reaction kinetics. The absorption of CO₂ as encountered in flue gases into aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), and NH₃ was carried out using a stirred vessel with a plane gas-liquid interface at 50 °C. Various operating parameters were tested to determine the effect of these variables on the absorption kinetics of the reactants in both gas and liquid phases and the effect of competitions between various reactants on the mass-transfer rate.

The observed absorption rate increases with increasing gas-liquid concentration, solvent concentration, temperature, and gas flow rate, but changes with the O₂ concentration and pH value. The absorption efficiency of MEA is better than that of NH₃ and DEA, but the absorption capacity of NH₃ is the best. The active energies of the MEA and NH₃ with CO₂ are 33.19 and 40.09 kJ/mol, respectively.     

H(+)/phenanthrene symporter and aquaglyceroporin are implicated in phenanthrene uptake by wheat (Triticum aestivum L.) roots

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous organic pollutants that are toxic to human and nonhuman organisms. Dietary intake of PAHs is a dominant route of exposure for the general population because food crops are a major source of dietary PAHs. The mechanism for crop root uptake of PAHs remains unclear. Here we reveal that wheat root uptake of PAHs involves active and passive processes. The passive uptake is mercury and glycerol dependent. Mercury and glycerol inhibit uptake, indicating that aquaglyceroporins sensitive to mercury contribute to passive uptake. Active uptake is mediated by a phenanthrene/H symporter. The electrical response of wheat roots triggered by phenanthrene consists of two sequential phases: depolarization followed by repolarization. The depolarization is phenanthrene concentration dependent, with saturation kinetics that have an apparent of K(m) 10.8 μmol L(-1). As uptake proceeds, external solution pH increase is noticed. Lower pH favors the uptake. Vanadate and 2,4-dinitrophenol suppress the electrical response to phenanthrene and phenanthrene uptake, suggesting that plasma membrane H(+)-ATPase is involved in the establishment of an electrochemical proton gradient acting as a driving force for active uptake. Therefore, it is suggested that aquaglyceroporin and phenanthrene/H symporter are implicated in phenanthrene uptake. Our results provide insight into PAH uptake mechanism in wheat roots that is relevant to strategies for reducing PAH accumulation in wheat for food safety, improving phytoremediation of PAH-contaminated soils or water by agronomic practices and genetic modification to target remedial plants for higher PAH uptake capacity.