Reversibly enhanced aqueous solubilization of volatile organic compounds using a redox-reversible surfactant

Surfactant-enhanced remediation (SER) is an effective method for the removal of volatile organic compounds (VOCs) from contaminated soils and groundwater. To reuse the surfactant the VOCs must be separated from the surfactant solutions. The water solubility of VOCs can be enhanced using reversible surfactants with a redox-acive group, (ferrocenylmethyl)dodecyldimethylammonium bromide (Fcl2) and (ferrocenylmethyl)tetradecanedimethylammonium bromide (Fcl4), above and below their critical micelle concentrations (CMC) under reducing (I⁺) and oxidative (I²⁺) conditions. The CMC values of Fcl2 and Fcl4 in I⁺ are 0.94 and 0.56 mmol/L and the solubilization of toluene by Fcl2 and Fcl4 in I⁺ for toluene is higher than the solubilization achieved with sodium dodecyl sulfate, cetyltrimethylammonium bromide and Trition X-114. The solubilization capacity of the ferrocenyl surfactants for each tested VOCs ranked as follows: ethylbenzene > toluene > benzene. The solubilities of VOCs by reversible surfactant in I⁺ were 30% higher than those in I²⁺ at comparable surfactant concentrations. The effects of Fcl4 concentrations on VOCs removal efficiency were as follows: benzene > toluene > ethylbenzene. However, an improved removal efficiency was achieved at low ferrocenyl surfactant concentrations. Furthermore, the reversible surfactant could be recycled through chemical approaches to remove organic pollutants, which could significantly reduce the operating costs of SER technology.     

自然资源永续利用的条件与税收的作用——关于“节能减排”税收政策的理论思考

人类利用资源的矛盾,实质上源于人类对资源需求的不断增加与自然资源的自然供给的相对有限性之间的矛盾。要解决这一矛盾,实现资源的永续利用,就是要实现资源的人类需求与自然供给之间的平衡,即：自然资源需求量≤自然资源的最大供给能力;自然资源需求量的增长速度≤技术支持下的自然资源供给能力的提高速度。     

伪“零排放”尴尬了谁？

尽管缺乏具体数据而无法推断环保成本对企业盈利能力的实际影响,但降低成本、增加盈利却是造纸企业“顶风作案”的初衷。造纸的毛利率本来就比较低,成本即使只有几个点的提升,对企业盈利的影响也会很大。     

新型专性厌氧菌利用葡萄糖进行发酵产氢的实验研究

采用批式发酵法对厌氧产氢菌株Bacteria.P利用葡萄糖发酵,在底物浓度、初始pH值、接种比例等不同培养条件下的产氢能力进行了研究。结果表明:专性厌氧菌P是一种高效产氢的菌株,在葡萄糖质量浓度为10 g/L、初始pH为6.0、接种比例为1∶20时,发酵气体总产量和细胞干重达到最大值,分别为485 mL和0.836 g/L。     

浏阳市以专业化园区推动中小企业创新集聚发展

目前,占企业总数99%以上,提供城镇就业岗位75%以上的我国中小企业主要分布在县（市）区域。这一分布格局决定了县（市）企业创新主要指的就是中小企业创新,而县（市）创新主体的不完备性特征又决定了中小企业作为县（市）创新主要主体之一的重要地位。因此,如何采取有效措施提升中小企业自主创新能力,是关系到县域经济能否实现创新发展的关键环节。     

包头市环境保护能力建设存在问题及对策

对照环境保护五大能力标准化建设要求,分析包头市环境保护自身能力建设现状,目前主要存在的问题是机构不健全、编制不足、缺乏人才、设备短缺且落后、资金匮乏、信息化滞后,县级环保局尤为突出。文章从机构建设与人才培养、监测能力、信息公告制度,宣教能力、信息网络建设等方面提出了包头市环境保护能力建设的对策建议,为环保事业的发展提供决策参考和技术支持。     

2014年APEC期间北京市PM10和PM2.5氧化性损伤能力研究

为评估APEC会议期间联防联控措施对北京市大气可吸入颗粒物毒性的影响,采集2014年APEC会议前后3个月北京市大气PM₁₀和PM_2.5样品,应用质粒DNA损伤评价法来研究其氧化性损伤能力. 结果表明,APEC会议期间PM₁₀对DNA的损伤率高于PM_2.5,颗粒物对 DNA损伤率随剂量的增加而增加. 本研究用TD30值来指示颗粒物氧化性损伤能力,TD30为引起30%的DNA损伤率所需要的颗粒物剂量（单位为 μg·mL^-1）,TD30值越低,颗粒物氧化性损伤能力越强,APEC会议前后样品的TD30值表现为 APEC期间（11月）>APEC前（10月）>APEC后（12月）,说明氧化能力APEC后 >APEC前 >APEC期间. 用PM₁₀质量浓度乘上其在250 μg·mL^-1 剂量下的DNA损伤率得到颗粒物暴露毒性指数TI（toxic index）,与往年具有代表性月份样品的数据对比,TI大小顺序为2004年 >2014年 >2008年,说明大气中颗粒物暴露毒性随着政策控制力度的加大而降低.     

Comparison of quartz sand, anthracite, shale and biological ceramsite for adsorptive removal of phosphorus from aqueous solution

The choice of substrates with high phosphorus adsorption capacity is vital for sustainable phosphorus removal from waste water in constructed wetlands. In this study, four substrates were used： quartz sand, anthracite, shale and biological ceramsite. These substrate samples were characterized by X- ray diffractometry and scanning electron microscopy studies for their mineral components （chemical components） and surface characteristics. The dynamic experimental results revealed the following ranking order for total phosphorus （TP） removal efficiency： anthracite 〉 biological ceramsite 〉 shale 〉 quartz sand. The adsorptive removal capacities for TP using anthracite, biological ceramsite, shale and quartz sand were 85.87, 81.44, 59.65, and 55.98 mg/kg, respectively. Phosphorus desorption was also studied to analyze the substrates＇ adsorption efficiency in wastewater treatment as well as the substrates＇ ability to be reused for treatment. It was noted that the removal performance for the different forms of phosphorus was dependent on the nature of the substrate and the adsorption mechanism. A comparative analysis showed that the removal of particulate phosphorus was much easier using shale. Whereas anthracite had the highest soluble reactive phosphorus （SRP） adsorptive capacity, biological ceramsite had the highest dissolved organic phosphorus （DOP） removal capacity. Phosphorus removal by shale and biological ceramsite was mainly through chemical adsorption, precipitation or biological adsorption. On the other hand, phosphorus removal through physical adsorption （electrostatic attraction or ion exchange） was dominant in anthracite and quartz sand.     

Phosphatase activity and culture conditions of the yeast Candida mycoderma sp. and analysis of organic phosphorus hydrolysis ability

Orthophosphate is an essential but limiting macronutrient for plant growth. About 67% cropland in China lacks sufficient phosphorus, especially that with red soil. Extensive soil phosphorus reserves exist in the form of organic phosphorus, which is unavailable for root uptake unless hydrolyzed by secretory acid phosphatases. Thus, many microorganisms with the ability to produce phosphatase have been exploited. In this work, the activity of an extracellular acid phosphatase and yeast biomass from Candida mycoderma was measured under different culture conditions, such as pH, temperature, and carbon source. A maximal phosphatase activity of 8.47 × 10^5±0.11× 10^5 U/g was achieved by C. Mycoderma in 36 hr under the optimal conditions. The extracellular acid phosphatase has high activity over a wide pH tolerance range from 2.5 to S.0 （optimum pH 3.5）. The effects of different phosphorus compounds on the acid phosphatase production were also studied. The presence of phytin, lecithin or calcium phosphate reduced the phosphatase activity and biomass yield significantly. In addition, the pH of the culture medium was reduced significantly by lecithin. The efficiency of the strain in releasing orthophosphate from organic phosphorus was studied in red soil （used in planting trees） and rice soil （originating as red soil）. The available phosphorus content was increased by 230% after inoculating 20 days in rice soil and decreased by 50% after inoculating 10 days in red soil. This work indicates that the yeast strain C. mycoderma has potential application for enhancing phosphorus utilization in plants that grow in rice soil.     

采用精密度法评定总氮测量不确定度

采用top-down技术中的精密度法对环境水样中总氮的测量不确定度进行了评定。文章利用实验室内期间精密度实验结果、参加能力验证结果和实验室内标准样品的重复性测定结果,对实验室测量偏倚和精密度控制情况进行评估,并在保证实验室的测量过程处于统计受控状态下,参考能力验证的室间标准差作为测量不确定度的估计值。由于这种方法关注实验的整个过程,因此更能从整体上反映实验结果的测量不确定度;并且由于省去了传统bottom-up技术中复杂的实验设计和繁琐的合成计算,应用起来简便易行。