Leaching of styrene and other aromatic compounds in drinking water from PS bottles

Bottled water may not be safer, or healthier, than tap water. The present studies have proved that styrene and some other aromatic compounds leach continuously from polystyrene （PS） bottles used locally for packaging. Water sapmles in contact with PS were extracted by a preconcentration technique called as ＂purge and trap＂ and analysed by gas chromatograph-mass spectrometer （GC/MS）. Eleven aromatic compounds were identified in these studies. Maximum concentration of styrene in PS bottles was 29.5 μg/L. Apart from styrene, ethyl benzene, toluene and benzene were also quantified but their concentrations were much less than WHO guide line values. All other compounds were in traces. Quality of plastic and storage time were the major factor in leaching of styrene. Concentration of styrene was increased to 69.53 μg/L after one-year storage. In Styrofoam and PS cups studies, hot water was found to be contaminated with styrene and other aromatic compounds. It was observed that temperature played a major role in the leaching of styrene monomer from Styrofoam cups. Paper cups were found to be safe for hot drinks.     

橡■单宁去除水中有毒重金属离子的研究

研究了用橡单宁处理Ｐｂ２＋、Ｃｄ２＋、Ｃｒ３＋、Ｚｎ２＋、Ｍｎ２＋、Ｆｅ２＋六种重金属离子的最佳条件。结果表明，在中性或微碱性条件下，几种金属离子的最佳去除率分别可达８０６％、９２２％、８５３％、９１４％、８５０％、８６０％。探讨了橡单宁絮凝的机理。     

一次性塑料水杯与涂层纸杯的生命周期评价与分析

文章对日常使用的一次性塑料水杯与纸杯的全生命周期进行综合评价,比较两者对环境与人体健康的最终影响。采用了生命周期评价的技术路线与方法进行研究,最终得出一次性PE涂层纸杯的环境影响值大于PP塑料杯的结果。分析结果可得出纸杯在材料采用、制造、能耗等方面的缺陷导致了其环境影响值偏大,而PP塑料杯虽然在资源消耗与可降解性上存在劣势,但从全生命周期的视角上来看,却相对环境影响较小。     

铝合金杯形件反挤压力计算方法的评比

通过对铝合金杯形件反挤压力计算方法的评比 ,得到了其在不同变形程度下较接近于实测值的计算方法用以估算挤压力。经验证 ,所得结论是较可靠的 ,可用于指导生产实践。对于其它挤压条件 (不同挤压方式 ,挤压材料等 )下的同种问题 ,可以参照这种研究方法得出相应结论     

Reusable and disposable cups: An energy-based evaluation

A group of five different types of reusable and disposable hot drink cups have been analyzed in detail with respect to their overall energy costs during fabrication and use. Electricity generating methods and efficiencies have been found to be key factors in the primary energy consumption for the washing of reusable cups and a less important factor in cup fabrication. In Canada or the United States, over 500 or more use cycles, reusable cups are found to have about the same or slightly more energy consumption, use for use, as moulded polystyrene foam cups used once and then discarded. For the same area paper cups used once and discarded are found to consume less fossil fuel energy per use than any of the other cup types examined. Details of this analysis, which could facilitate the comparative assessment of other scenarios, are presented.     

宁波市水资源可持续利用的经济分析

随着经济社会的快速发展,宁波水资源短缺矛盾日益突出,通过对宁波市历年的水价、人均用水量、人均可支配收入的变化的分析可以看出水价与用水量的关系,重点探讨了引进市场机制,建立水权转让制度,改革水资源价格和水资源的开发管理方式,实行水资源的有偿使用和转让,优化配置水资源,提高水资源的使用效率和效益,以水资源的可持续利用支撑经济和社会的可持续发展.     

Evaluation of porous cup soil‐water samplers under laboratory conditions: Comparison of ceramic and PTFE cups

Three different types of soil solution samplers (two ceramic cups and PTFE) were tested in the laboratory to validate their use for collecting soil‐water samples and for monitoring the chemical composition of soil solutions. Interactions between porous materials and chemical solutions were examined under different experimental conditions for several major cations (Ca²⁺, Mg²⁺, Na⁺ and K⁺) and anions (HCO^‐ ₃, NO^‐ ₃, SO₄ ^2‐ and Cl^‐) and for several minor ions (NH⁺ ₄, NO^‐ ₄, PO₄ ^3‐and B).

The results show that ceramic cups are not inert for bicarbonate, calcium and phosphate ions. Their use is only valid for a limited number of ions such as chloride and nitrate which, however, are the most studied ions in field experiments. PTFE cups have less restrictions although their use in measuring sulphates, phosphates and ammonium presents some problems.

Choosing the appropriate type of cup depends on the objectives. In any case, laboratory experiments must be performed before installation.     

Recycling disposable cups into paper plastic composites

The majority of disposable cups are made from paper plastic laminates (PPL) which consist of high quality cellulose fibre with a thin internal polyethylene coating. There are limited recycling options for PPLs and this has contributed to disposable cups becoming a high profile, problematic waste. In this work disposable cups have been shredded to form PPL flakes and these have been used to reinforce polypropylene to form novel paper plastic composites (PPCs). The PPL flakes and polypropylene were mixed, extruded, pelletised and injection moulded at low temperatures to prevent degradation of the cellulose fibres. The level of PPL flake addition and the use of a maleated polyolefin coupling agent to enhance interfacial adhesion have been investigated. Samples have been characterised using tensile testing, dynamic mechanical analysis (DMA) and thermogravimetric analysis. Use of a coupling agent allows composites containing 40 wt.% of PPL flakes to increase tensile strength of PP by 50% to 30 MPa. The Young modulus also increases from 1 to 2.5 GPa and the work to fracture increases by a factor of 5. The work demonstrates that PPL disposable cups have potential to be beneficially reused as reinforcement in novel polypropylene composites.     

A summary of environmental legislation targeting disposable diapers and review of related literature

In recent years state and local governments, as well as private citizens, have become very concerned about the mounting solid waste disposal problem facing our nation. Special concern has been expressed over the presence of disposable diapers in the solid waste stream. Responding to the concerns, legislators in at least 25 states proposed actions regarding disposable diapers between 1990 and 1992. Several factors contributed to the number of legislative proposals regarding disposable diapers over the past few years. First was the public's and legislators' misconception about the contribution of disposable diapers to the solid waste stream. Second was an erroneous assumption held by the public and some legislators that biodegradation readily occurs in landfills. Third was the desire to increase demand for agricultural products by requiring the use of degradable products. These contributing factors and other issues surrounding the proposal and passage of environmental legislation pertaining to disposable diapers are presented in this paper and the relevant literature is summarized. To provide the necessary context, the paper contains a review of the literature concerning disposable diapers, their composition and usage; and their environmental impact and fate and a comparison of their performance and cost to those of cloth diapers.     

Biological recycling of used baby diapers in a small-scale composting system

In Mexico used disposable diapers account for 6.5% of the urban waste that is sent to landfills, as no alternative treatment or valorization options is available. Due to their mixed organic–inorganic composition, they are usually perceived as a problematic non-biodegradable waste; nevertheless, due to their high cellulose content they could be recycled biologically in order to recover the nutrients present in them. This research assessed the feasibility of composting them along with yard waste, in 200 L bioreactors. An initial mixture of fresh trims of grass (55%), dry leaves (10%), fresh leaves (15%) and mulch (20%) was prepared and characterized to achieve an adequate C/N relationship. In the selected reactors 30% (mass basis) of previously shredded used baby diapers containing urine was added. The composting process lasted three months. Temperature, moisture, pH, nitrogen, CO₂ production, organic matter, C/N ratio, volume and mass reduction were measured and recorded periodically. The composting process was not affected by the presence of diapers. Temperature rose to 60–70 °C in the initial thermophilic phase, and reached a final plateau of 20–30 °C. The initial high temperatures allowed to eliminate the pathogens, as shown in the microbiological tests. Volume and mass of the substrates decreased more than 50% by the end of the process. Mass reduction for diapers was 87%, and only the plastic films were recovered. The final compost had good quality and accomplished with the limits set in the local regulation, except by pH, which has slightly above the set limit. It can be used as a soil amendment, as shown in the phytotoxicity tests performed using tomato. The results show that this is a feasible, affordable option for the valorization of used disposable diapers, which could be applied in small communities or daycare centers.