生物表面活性剂茶皂素离子浮选去除废水中镉离子

对生物表面活性剂茶皂素作为离子浮选剂去除废水中镉离子的能力进行了研究,对影响去除率和富集比的物理因素(包括溶液初始pH值、C茶皂素CCd2+(摩尔比)、离子强度(NaCl和NaNO3))和动力学参数(包括浮选时间和通气量)进行了考察.C茶皂素CCd2+=2∶1,pH为6.0,通气量为0.15L·min-1时得到了最佳去除效果,去除率达到85.87%,Cd2+的富集比达到19.43;而在C茶皂素CCd2+=2∶1,pH为8.0,通气量0.15L·min-1时,Cd2+去除率达到70.97%,富集比高达32.17.随着溶液离子强度的增强,镉离子去除率和富集比显著降低.泡沫浓缩液中加碱回收Cd2+,回收率为79.62%.     

利用石油裂解副产物做溶剂回收废旧聚苯乙烯泡沫塑料(FPS)的研究

利用石油裂解副产物为溶剂回收废旧聚苯乙烯泡沫塑料,以废治污。溶剂低毒、对聚苯乙烯泡沫塑料溶解速度快、溶解量大,资源丰富、价廉易得,回收率高,可循环使用。     

Plastics in the Marine Environment: Problems and Solutions

Plastics debris is known to be present in all of the world's oceans, and on most amenity beaches, although comparatively little data are available to provide reliable information on the extent of damage from this pollution, and on its spatial and temporal variations.

Marine pollution by plastics has been shown to be damaging to marine mammals, birds and reptiles. This is due to entanglement in packaging bands, synthetic ropes and lines, or drift nets; or by the ingestion of small items of plastics debris. More research is needed to quantify the extent of the problems.

Wider use of degradable plastics will not solve the problems of plastics pollution. Their lifetimes are relatively long and unpredictable, and they are not generally acceptable for recycling.

Marine plastics pollution may be alleviated by the judicious application of both economic incentives and legislation, designed to decrease their use, to increase the rate of recycling, and to restrict uncontrolled discards.     

A review on tertiary recycling of high-density polyethylene to fuel

Plastics have become an indispensable ingredient of human life. They are non-biodegradable polymers of mostly containing carbon, hydrogen, and few other elements such as chlorine, nitrogen etc. Rapid growth of the world population led to increased demand of commodity plastics. High density poly ethylene is one of the largest used commodity plastics due to its vast applications in many fields. Due to its non bio degradability and low life, HDPE contributes significantly to the problem of Municipal Waste Management. To avert environment pollution of HDPE wastes, they must be recycled and recovered. On the other hand, steady depletion of fossil fuel and increased energy demand, motivated the researchers and technologists to search and develop different energy sources. Waste to energy has been a significant way to utilize the waste sustainably, simultaneously add to meet the energy demand. Plastics being petrochemical origin have inherently high calorific value. Thus they can be converted back to useful energy. Many researches have been carried out to convert the waste plastics into liquid fuel by thermal and catalytic pyrolysis and this has led to establishment of a number of successful firms converting waste plastics to liquid fuels. This paper reviews the production and consumption HDPE, different methods of recycling of plastic with special reference to chemical degradation of HDPE to fuel. This also focuses on different factors that affect these degradations, the kinetics and mechanism of this reaction.     

Reflections about three influential Ambio articles impacting environmental biogeochemistry research and knowledge: This article belongs to Ambio’s 50th Anniversary Collection. Theme: Environmental contaminants

Reflections about three influential environmental contaminants papers published in Ambio are presented. The PCB Story by Jensen in (1972) had a very important influence on environmental chemistry. This is captured by way of comments and personal anecdotes. Wania’s and MacKay’s (1993) paper highlights the physical chemistry underlying transport of PCBs and organochlorine pesticides from temperate zone ecosystems to Polar Regions. Their paper exemplifies how principles of chemistry and environmental processes informed understanding the biogeochemical cycles of chemicals of environmental concern (CEC). Mergler et al.’s (2007) paper reviews knowledge of methyl mercury exposure and impacts in humans and served as an example of how to approach exposure and human health concerns for all CECs. All great progress. Then, the question: “How we missed for two decades the importance of plastics in the environment identified in a paper published the same year as The PCB Story? Are we missing yet another important environmental contaminant now?     

Biodegradation of Compostable Plastics in Green Yard-Waste Compost Environment

Compostable plastic materials, produced from polylactic acid (PLA), corn starch, or sugarcane, degraded in a green yard-waste compost environment. The compostable plastics claim to meet ASTM D6400 standards for biodegradation, sustainable plant growth, and eco-toxicity. Biodegradation was measured by disintegration studies over 20 weeks. The commercially available compostable products, made from PLA, sugarcane, or corn starch, biodegraded while in a commercial compost facility with other common yard waste compostable items. The PLA container, cup, and knife completely degraded in 7 weeks at a rate similar to the Avicell micro-cellulose control. The corn starch-based trash bag and sugarcane plate degraded at a similar rate as the Kraft paper control. The three materials degraded between 80% and 90% after 20 weeks.     

Liquid-phase hydrodechlorination of trichloroethylene driven by nascent H2 under an open system: Hydrogenation activity, solvent effect and sulfur poisoning

Hydrodechlorination is a promising technology for the remediation of water body contaminated with trichloroethylene (TCE). In this work, the liquid-phase hydrogenation of TCE by Raney Ni (R-Ni) and Pd/C under an open system have been studied, in which nascent H₂ (Nas-H₂) generated in situ from the cathode acted as a hydrogen source. Experimental results showed that TCE was completely eliminate from the solution through the synergistic effects of hydrodechlorination and air flotation due to the formation of continuous micro/nano-sized Nas-H₂ bubbles from the cathode. Furthermore, the effects of inorganic anions and organic solvents on R-Ni and Pd/C hydrogenation activity were investigated, respectively. The results showed that NO₃^? and acetonitrile can form a competitive reaction with TCE; Sulfur with lone-pair electrons will cause irreversible poisoning to these two catalysts, and have a stronger inhibitory effect on Pd/C. This work helps to realize the separation of volatile halogenated compounds from water environment and provides certain data support for the choice of catalyst in the actual liquid-phase hydrogenation system.     

The electrocoagulation/flotation study: The removal of heavy metals from the waste fountain solution

The objective of this study was to investigate the possibility of heavy metals (copper, zinc and nickel) removal from the waste fountain solution by the electrocoagulation/flotation (ECF) treatment. After the printing process, the fountain solution changes its composition due to direct contact with different printing materials (plates, inks, etc.) and becomes enriched with metals. The effect of operational parameters, such as electrode materials and combinations, current density, interelectrode distance and operating time, was studied. Also, response surface methodology (RSM) was applied to evaluate the effect of main operational variables and to get a balanced removal efficiency of metals from waste fountain solution by ECF treatment. The iron/iron electrode combination yields a higher percentage of copper and zinc removal efficiency (>95% and >80%, respectively), while for nickel the aluminum/iron and iron/aluminum electrode combinations (>95 and >85%, respectively) proved to be more successful. The optimum interelectrode distance was 1.0 cm (for copper) and 1.5 cm (for zinc and nickel) for all current densities. Heavy metal removal efficiency increases with the increase of electrolysis time for all electrode combinations. Also, the increase of current density improves the ECF removal efficiency. Based on the results obtained through RSM, the optimized parameters for the ECF waste fountain solution treatment for metal removal were identified as: Fe(−)/Al(+) electrode with interelectrode distance of 1.5 cm, operating time of 60 min and current density of 8 mA cm⁻². Overall, the ECF treatment was proven very efficient in the removal of heavy metals from the waste fountain solution under optimum conditions.     

基于实时控制的电絮凝-气浮处理重金属清淤尾水

针对重金属清淤尾水具有污染物浓度高、水质波动大、沉淀性能差等特点,选取pH值和浊度作为实时监测因子,并借助沉淀模拟和数据拟合等手段,建立了比电流与镉残留量之间的实时控制响应模型.结果表明:铝-电絮凝-气浮兼有中和pH值和改善泥水分离的优点,实现了重金属铅、镉和锌的达标排放;此外实时控制策略节省了35.8%的材料消耗和43.4%的电能消耗以及降低了47.9%的产泥量.     

炼油废水处理设施气浮池及溶气罐的改进

针对炼油废水处理设施气浮池及溶气罐中存在的问题，采取了相应的改进措施，取得了满意的效果。并从设计运行控制参数的改进以及流体力学的基础理论等方面进行了论述。