Chromate transport through columns packed with surfactant-modified zeolite/zero valent iron pellets

Chromate transport through columns packed with zeolite/zero valent iron (Z/ZVI) pellets, either untreated or treated with the cationic surfactant hexadecyltrimethylammonium (HDTMA), was studied at different flow rates. In the presence of sorbed HDTMA, the chromate retardation factor increased by a factor of five and the pseudo first-order rate constant for chromate reduction increased by 1.5-5 times. The increase in rate constant from the column studies was comparable to a six-fold increase in the rate constant determined in a batch study. At a fast flow rate, the apparent delay in chromate breakthrough from the HDTMA modified Z/ZVI columns was primarily caused by the increase in chromate reduction rate constant. In contrast, at a slower flow rate, the retardation in chromate transport from the HDTMA modified Z/ZVI columns mainly originated from chromate sorption onto the HDTMA modified Z/ZVI pellets. Due to dual porosity, the presence of immobile water was responsible for the earlier breakthrough of chromate in columns packed with zeolite and Z/ZVI pellets. The results from this study further confirm the role of HDTMA in enhancing sorption and reduction efficiency of contaminants in groundwater remediation.     

Decolorization of cationic red X-GRL by wet air oxidation: performance optimization and degradation mechanism

The decolorization of a strong colored azo dye solution of cationic red X-GRL was investigated by wet air oxidation under relatively mild conditions (60-180 degrees C, PO2 = 0-1.2 MPa). Mono-factor experiments were carried out to investigate the effect of the operation factors and the relatively important parameters were selected for optimization using response surface methodology to explore the interactions of these relatively important parameters. Model regeneration analysis and the check experiments showed that the data of the general linear model agreed with the experiment results well. With multistage Monte-Carlo optimization, the best region of these variables could be predicted to dye color removal. At typical operational conditions, the intermediates of dye degradation were detected and confirmed by GC/MS system. Considering the intermediates and the structure analysis with the help of Gaussian 03W (version 6.0) and the theory of dye color, a possible degradation mechanism for the wet air oxidation of cationic red X-GRL was discussed and the probable degradation pathway was deduced.     

A biomimetic absorbent for removal of trace level persistent organic pollutants from water

A novel biomimetic absorbent containing the lipid triolein was developed for removing persistent organic pollutants (POPs) from water. The structural characteristics of the absorbent were obtained by SEM and a photoluminescence method. Under optimum preparation conditions, triolein was perfectly embedded in the cellulose acetate (CA) spheres, the absorbent was stable and no triolein leaked into the water. Dieldrin, endrin, aldrin and heptachlor epoxide were effectively removed by the CA--triolein absorbent in laboratory batch experiments. This suggests that CA-triolein absorbent may serve as a good absorbent for those selected POPs. Triolein in the absorbent significantly increased the absorption capacity, and lower residual concentrations of POPs were achieved when compared to the use of cellulose acetate absorbent. The absorption rate for lipophilic pollutants was very fast and exhibited some relationship with the octanol--water partition coefficient of the analyte. The absorption mechanism is discussed in detail.     

强化特种设备及作业人员的安全管理是维系化工企业安全生产的关键

特种设备安全工程是安全管理工程的一个分支,也是企业管理工程的一个重要组成部分。特种设备安全工程主要包括承压设备与起重设备安全管理领域所涉及到的设计、制造、使用、维护、检修、监测、事故调查及人员培训教育等方面的内容。特种设备安全状况及特种作业人员的安全技术素质与企业的安全生产密切相关,提高设备本质安全和作业人员的安全意识与安全操作技能是企业安全管理工作中必不可少的内容。     

水体环境中氟喹诺酮类药物的污染现状及分析方法

阐述了水体环境中的氟喹诺酮类（FQs）药物的来源和污染现状,介绍了FQs在水体环境中的迁移、转化和转归途径,归纳了各种当前使用较多的FQs分析检测方法的功能特点和适用条件。指出今后在FQs分析技术的开发上,应注重提高检测容量、降低检出限和削减环境负面影响因素。     

类芦对铅的耐性及富集能力探讨

通过野外调查和盆栽试验,研究了类芦(Neyraudia reynaudiana)对Pb的耐性和富集能力.研究结果表明,类芦对Pb耐受的临界浓度为800 mg/kg,在此浓度以下Pb对类芦的生长基本无抑制作用.随着处理浓度的增加,类芦生长变缓慢、出现中毒症状,但仍能存活.从富集能力来看,土壤Pb为中低浓度时,类芦的富集能力较强,但Pb浓度超过1 000 mg/kg后地上部富集量增加缓慢,而根部的含量则降低.在各种Pb处理浓度下,类芦地上部Pb含量均大于根部,说明这种植物对Pb有较好的迁移能力.研究发现,类芦具有较高的生物量,因此其地上部Pb迁移总量较高,在土壤Pb浓度为800 mg/kg时类芦地上部的迁移总量可达到221.77 mg/m2.综合分析可知,类芦对中度Pb污染土壤的植物修复具有较大的潜力.     

Risk assessment of trace elements in cultured freshwater fishes from Jiangxi province,China

The levels of trace elements (As, Cd, Cr, Cu, Fe, Ni, Pb, Se, and Zn) in eight species of cultured freshwater fishes from Jiangxi province were determined by inductively coupled plasma-mass spectroscopy. All the studied trace element levels in fish muscles from Jiangxi province did not exceed Chinese national standard and European Union standard, and they were often lower than previous studies. The calculated target hazard quotient values for all the studied trace elements in fish samples were much less than 1, suggesting that the studied trace elements in fish muscles from Jiangxi province had not pose obvious health hazards to consumers. As and Cd concentrations in northern snakehead were much higher than that in other fishes, demonstrating that this fish species could be valuable as a bioindicator of As and Cd in environmental surveys. In addition, the highest concentrations of Fe, Zn, and moderate contents of other essential trace elements in crucian carp indicated that crucian carp could be a good nutrient source of essential trace elements for human health.     

Rubber and pulp plantations represent a double threat to Hainan's natural tropical forests

Hainan, the largest tropical island in China, belongs to the Indo-Burma biodiversity hotspot and harbors large areas of tropical forests, particularly in the uplands. The Changhua watershed is the cradle of Hainan's main river and a center of endemism for plants and birds. The watershed contains great habitat diversity and is an important conservation area. We analyzed the impact of rubber and pulp plantations on the distribution and area of tropical forest in the watershed, using remote sensing analysis of Landsat images from 1988, 1995 and 2005. From 1988 to 1995, natural forest increased in area (979-1040?sq?km) but decreased rapidly (763?sq?km) over the next decade. Rubber plantations increased steadily through the study period while pulp plantations appeared after 1995 but occupied 152?sq?km by 2005. Rubber and pulp plantations displace different types of natural forest and do not replace one another. Because pulp is not as profitable as rubber and existing pulp processing capacity greatly exceeds local supply, considerable pressure exists on remaining upland forests. We recommend for future management that these plantation forests be reclassified as 'industrial', making a clear policy distinction between natural and industrial forestry. Additionally, the local government should work to enforce existing laws preventing forest conversion on marginal and protected areas.     

德国环境设备责任制度初探

德国《民法典》确定了一般环境侵权的规则——行为责任,再以《环境责任法》确立了特殊的环境侵权的规则——设备责任。设备侵权是危险责任的一种,其构成要件有两个:设备运营对环境产生不良影响进而导致损害;人身、财产受侵害。设备责任的承担不要求设备运营人的过错。设备责任归责采用因果关系推定原则。