再生铜行业环境管理问题的若干思考和建议

随着我国铜冶炼(原生铜和再生铜)行业对含铜二次资源需求量的增加,集废旧资源回收、拆解和分选、二次资源出售、铜再生利用于一体的产业链逐渐发展壮大起来。然而高能耗、高污染、低质量、低产出的特点在再生铜行业依然存在,环境监管政策和标准也不健全不完善。随着人们对美丽生态环境诉求的增加,必须加强有色金属行业的环境管理。本文对再生铜行业发展和环境管理做了一些思考,特别是对再生铜行业环境管理存在的问题进行了分析,并针对问题提出了几点政策性建议,以期为我国再生铜产业的环境友好发展和环境监管提供借鉴。     

化学合成聚3-羟基丁酸酯薄膜的生物降解性

利用土壤埋藏,海水降解,活性污泥及高等真菌降解实验对化学法合成的聚３－羟基丁酯,薄膜进行了生物降解性研究。结果表明,降解ＰＨＢ薄膜的微生分布比较广泛;     

纳米羟基磷灰石对电子垃圾拆解地农田土壤Pb生物可利用性的影响

为了研究钝化剂对电子垃圾拆解地农田土壤中重金属Pb生物可利用性的影响,采用盆栽试验,在种植油菜和白菜的土壤中加入不同质量比的纳米羟基磷灰石(n-HAP),研究Pb形态、油菜和白菜生物量、油菜和白菜中Pb的累积量,评价纳米羟基磷灰石对Pb生物可利用性的影响.结果表明,加入5 g/kg、10 g/kg、15 g/kg、20 g/kg和25 g/kg纳米羟基磷灰石后,油菜和白菜生物量增加,且油菜生物量大于白菜生物量;油菜内Pb累积量小于白菜内Pb累积量;土壤中残渣态Pb质量比增加,可交换态Pb质量比减少,有效态Pb质量比与Pb生物可利用性显著降低(p＜0.05),与对照组相比,种植油菜和白菜土壤中Pb的生物可利用性分别降低了25.53％～82.77％和45.79％～71.68％.当纳米羟基磷灰石质量比为20g/kg时,油菜和白菜生物量较大,而且对Pb的累积量最低,种植油菜和白菜土壤中Pb的生物可利用性分别降低了81.84％和70.89％.研究表明,纳米羟基磷灰石的适宜投加量为20g/kg,而油菜为理想植物.     

台州水系表层沉积物典型POPs污染现状及生态风险

为探讨典型废物拆解地工业结构转型期环境POPs(persistent organic pollutants,持久性有机污染物)污染特征变化情况,使用气相色谱/高分辨质谱法测定了台州水系表层沉积物中PCDD/Fs(二英类)、dl-PCBs(共平面多氯联苯)和PBDEs(多溴联苯醚),并利用主因子分析等手段分析了其来源. 结果表明,台州椒江和金清闸海湾2387-PCDD/Fs毒性当量浓度(以WHO₂₀₀₅-TEQ计,下同)中位值分别为3.18和1.91 ng/kg,dl-PCBs毒性当量浓度分别为0.26和0.62 ng/kg,w(∑PBDEs)分别为22.5和19.7 μg/kg,处于我国和全球河流(海湾)表层沉积物POPs污染的中等水平,低于其他电子废物拆解地等严重污染区. 台州河流(海湾)表层沉积物PCDD/Fs主要来源于燃煤,dl-PCBs主要来源于历史上多氯联苯的使用或电子废物拆解活动,PBDEs主要来源于相关阻燃剂的使用和电子废物拆解活动. 位于化工园区排水口的YTZ采样点PCDD/Fs和dl-PCBs的毒性当量浓度分别达到6.54×104和7.84×103 ng/kg,污染可能来源于化工废料加工和再生金属生产,表明台州在工业结构转型期出现的新POPs污染源,应引起重视. 台州部分表层沉积物样品中的PCDD/Fs和dl-PCBs的总毒性当量浓度超过美国和加拿大的沉积物质量指导值,存在一定的生态风险.      

Determination of traces of fluorine,chlorine, bromine,cadmium and lead in plastic materials

This paper describes the quantitative determination of F, Cl, Br, Cd and Pb in plastic materials. The concentration of the elements Cl, Br, Cd and Pb is first semiquantitatively measured by X‐ray fluorescence spectrometry (XRF) directly in the solid sample with a detection limit of approximately 10 μg/g. Afterwards, F and any of the other elements which exceed the limit values for materials which are disposable without special precautions are measured after the digestion of the material. The samples are digested either under pressure in an oxygen atmosphere for F, Cl and Br or under pressure with nitric acid for Cd and Pb. The digestion converts the halides to the anions which are measured potentiometrically (F^‐, Br^‐) or with ion chromatography (Cl^‐). Cd and Pb are measured by graphite furnace atomic absorption spectrometry (GF‐AAS). The determination limits achieved are 20 μg/g for F and Br, 250 μg/g for Cl, 0.01 μg/g for Cd and 0.2 μg/g for Pb, all below the limit values set by current regulations in Switzerland.     

废弃泡沫塑料的疏浚泥固化处理技术的研究

提出采用疏浚泥固化技术治理由废弃泡沫塑料引起的白色污染 ,既可解决疏浚泥及废弃泡沫塑料对环境的污染 ,又可废物利用产生新型土工材料。研究这一方法的技术可行性 ,对其综合性技术经济效益进行了评价。     

Boiling treatment of ABS and PS plastics for flotation separation

A new physical method, namely boiling treatment, was developed to aid flotation separation of acrylonitrile–butadiene–styrene (ABS) and polystyrene (PS) plastics. Boiling treatment was shown to be effective in producing a hydrophilic surface on ABS plastic. Fourier Transform Infrared analysis was conducted to investigate the mechanism of boiling treatment of ABS. Surface rearrangement of polymer may be responsible for surface change of boiling treated ABS, and the selective influence of boiling treatment on the floatability of boiling treated plastics may be attributed to the difference in the molecular mobility of polymer chains. The effects of flotation time, frother concentration and particle size on flotation behavior of simple plastic were investigated. Based on flotation behavior of simple plastic, flotation separation of boiling treatment ABS and PS with different particle sizes was achieved efficiently. The purity of ABS and PS was up to 99.78% and 95.80%, respectively; the recovery of ABS and PS was up to 95.81% and 99.82%, respectively. Boiling treatment promotes the industrial application of plastics flotation and facilitates plastic recycling.     

Sustainable design for automotive products: Dismantling and recycling of end-of-life vehicles

The growth in automotive production has increased the number of end-of-life vehicles (ELVs) annually. The traditional approach ELV processing involves dismantling, shredding, and landfill disposal. The “3R” (i.e., reduce, reuse, and recycle) principle has been increasingly employed in processing ELVs, particularly ELV parts, to promote sustainable development. The first step in processing ELVs is dismantling. However, certain parts of the vehicle are difficult to disassemble and use in practice. The extended producer responsibility policy requires carmakers to contribute in the processing of scrap cars either for their own developmental needs or for social responsibility. The design for dismantling approach can be an effective solution to the existing difficulties in dismantling ELVs. This approach can also provide guidelines in the design of automotive products. This paper illustrates the difficulty of handling polymers in dashboards. The physical properties of polymers prevent easy separation and recycling by using mechanical methods. Thus, dealers have to rely on chemical methods such as pyrolysis. Therefore, car designers should use a single material to benefit dealers. The use of materials for effective end-of-life processing without sacrificing the original performance requirements of the vehicle should be explored.     

浅谈国际原油价格暴跌对进口废塑料行业的影响及建议

作为资源的重要补充,近年来国内塑料加工行业对进口废塑料的需求市场不断扩大,但作为原油的下游产品,因原油价格波动带来的经营影响和环保风险不容忽视。为有效规避风险,提升行业竞争力,在源头控制、行业转型、通关便利等方面提供可行性建议。     

Thermogravimetric pyrolysis of waste polyethylene-terephthalate and polystyrene: A critical assessment of kinetics modelling

Pyrolysis is considered as possible technique to thermally convert waste plastics into chemicals and energy. Literature on experimental findings is extensive, although experiments are mostly performed in a dynamic heating mode, using thermogravimetric analysis (TGA) and at low values of the heating rate (mostly below 30 K/min). The present research differs from literature through the application of far higher heating rates, up to 120 K/min. The use of these dynamic results to define the reaction kinetics necessitates the selection of an appropriate reaction mechanism, and 21 models have been proposed in literature considering the rate limiting step being diffusion, nucleation or the reaction itself.The current research studied the cracking of PET and PS by TGA at different heating rates (temperature ramps). Results were used to check the validity of the proposed mechanisms. Several conclusions are drawn: (i) to obtain fair results, the heating ramp should exceed a minimum value, calculated at 30 K/min for PET and 80 K/min for PS; (ii) application of the majority of the models to experimental findings demonstrated that they do not meet fundamental kinetic considerations and are questionable in their use; and (iii) simple models, with reaction order 1 or 2, provide similar results of the reaction activation energy.A further comparison with literature data for dynamic and isothermal experiments confirms the validity of these selected models. Since TGA results are obtained on a limited amount of sample, with results being a strong function of the applied heating rate, the authors believe that isothermal experiments, preferably on a large scale both towards equipment and/or sample size, are to be preferred.