Thermal decomposition of cement–asbestos at 1100 °C: how much “safe” is “safe”?

Journal of Material Cycles and Waste Management - The products of cement–asbestos treated in air at 1100 °C were characterized by a multi-methodological approach to determine:...     

Long Term Trends in Concentration of Major Pollutants (SO<Subscript>2</Subscript>, CO,NO, NO<Subscript>2</Subscript>, O<Subscript>3</Subscript> and PM<Subscript>10</Subscript>) in Prague – Czech Republic (Analysis of Data Between 1992 and 2005)

To assess the effect of changes in traffic density and fuels used for heating at the beginning of the 1990s, 1992–2005 monthly averages of PM₁₀, SO₂, NO₂, NO, CO and O₃ from Prague, the Czech capital, were analyzed together with long term trends in emissions of major pollutants, fuel consumption and number of vehicles registered in Prague. The data from all monitoring stations were retrieved from the database of the state automated monitoring system. Correlation coefficients between ambient monthly averaged temperature and all pollutants of concern showed distinct seasonal trends. The results showed that while SO₂ and to some extent also CO concentrations dropped namely in the first half of the analyzed period (1992–1997) as a result decreased fossil fuel consumption for local heating, the behaviour of other pollutant concentrations followed a different pattern. PM₁₀ concentrations decreased during the beginning of the 1990s but showed a sign of increase after 2000. Concentrations of ozone and NO₂ did not reveal any significant change throughout the whole studied period. It can be concluded that during the studied period traditional urban sources of pollution, such as coal and oil combustion, lost their importance but were simultaneously substituted by pollutants from automotive transport (namely PM and NO₂) making the problem of air quality even worse.     

Biodegradation of Poly-ε-caprolactones and Poly-<Emphasis Type="SmallCaps">l</Emphasis>-lactides by Fungi

This work assessed biodegradation, by Aspergillus, Fusarium, Penicillium and Parengyodontium fungi, of four samples of poly-ε-caprolactone (PCL), three samples of poly-l-lactide (PLA) and one sample of poly-d,l-lactide (DL-PLA) produced by ring-opening polymerization initiated by aluminium complexes of corresponding lactones. Mesophilic fungal strains actively biodegrading PCL (F. solani) and PLA (Parengyodontium album and A. calidoustus) were selected. The rate of degradation by the selected fungi was found to depend on the physicochemical and mechanical properties of the polymers (molecular weight, polydispersity, crystallinity). The most degradable poly-ε-caprolactone sample was shown to have the lowest molecular weight; the most biodegradable polylactide DL-PLA had the lowest crystallinity. Mass spectral analysis of biodegraded polymer residues showed PCL to be degraded more intensively than PLA. It is established that in the case of Parengyodontium album the colonization of the films of polypropylene composites with DL-PLA is observed, which will undoubtedly contribute to their further destruction under the influence of abiotic factors in the environment.     

Biodegradation of Poly(ε-caprolactone) (PCL) Film by <Emphasis Type="Italic">Alcaligenes faecalis</Emphasis>

The biodegradation behavior of PCL film with high molecular weight (80,000 Da) in presence of bacterium Alcaligenes faecalis and the analysis of degraded polymer film have been carried out. Thin Films of PCL were prepared by means of solution casting method and the bacterial degradation behavior was carried in basal medium, in presence of bacteria with time variation after UV treatment. It was observed that after UV treatment the degradation of polymer film was increased and the degradation rate followed a three steps degradation mechanism. The degraded polymer film was analyzed by means of Differential Scanning Calorimeter (DSC), Thermo Gravimetric Analyzer (TGA) and Fourier Transform Infrared Spectroscope (FTIR). DSC results revealed that at the initial stages of the degradation up to 15–20 days, the bacterium preferentially degrades the amorphous parts of the polymer film over the crystalline zone. Thermo gravimetric analysis highlighted the low temperature stability of degraded films with extent of degradation. FTIR results showed the chain scission mechanism of the polymer chains and also supported the preferential degradation of amorphous phase over crystalline phase in the initial stages of the degradation.     

Morphology of <Emphasis Type="Italic">Penicillium funiculosum</Emphasis> During Biodegradation of Poly (β-hydroxybutyrate-co-β-hydroxyvalerate) [PHBV] with Poly (ε-Caprolactone) [PCL] Blends

Blends of poly (β-hydroxybutyrate-co-β-hydroxyvalerate) with poly (ε-caprolactone) were produced using melt mixing and solvent casting techniques. The biodegradation of blends was tested based in the ASTM G21-90 using Penicillium funiculosum fungal specie. The CO₂ production during biodegradation was measured and fitted using the Gompertz model. Biodegradation of blends varies according to the mixing technique and the proportion of bacterial polymers in the blends. Although lag phase was larger, solvent-casted blends were easier to degrade due to their porous surface and relative lower crystallinity. P. funiculosum morphology during biodegradation appeared to be related to carbon availability i.e. larger and more complex conidiophores, more phialides per conidiophore and the presence of double-phialides, were found in blends with higher PHAs proportion. P. funiculosum morphology was independent to the blending technique used. Hence, morphology of P. funiculosum could be useful as a reference for carbon bioavailability of the blends.     

Recovery of residual metals from − 0.5 mm non-metallic fractions in WPCBs using electrostatic separation enhanced by air classification

Journal of Material Cycles and Waste Management - Electrostatic separation is a cleaning physical method to recover metals from waste printed circuit boards (WPCBs), but it has poor separation...     

中国&#183;西南再生资源产业基地奠基

2009年10月18日,投资32亿元的西南再生资源产业基地在四川内江正式破土动工,一期投资4亿元,主要包括再生资源市场交易区等,预计2010年建成投产。该基地将成为西南地区最大的废旧塑料回收和再生产的产业基地。     

Viscoelastic Characterization and Degradation Stability Investigation of Poly(butylene-adipate-co-terephthalate) – Calcium-Phosphate Glass Composites

Journal of Polymers and the Environment - In this work new biodegradable composite materials based on poly(butylene-adipate-co-terephthalate) (PBAT) reinforced with water-soluble calcium-phosphate...     

Thermal Properties and Crystallization Behavior of Novel Biodegradable Poly(hexamethylene succinate-<Emphasis Type="Italic">co</Emphasis>-6 mol% butylene succinate) and Poly(hexamethylene succinate)

In this research, the thermal properties and crystallization behavior of novel poly(hexamethylene succinate-co-6 mol% butylene succinate) (PHBS) and its homopolymer poly(hexamethylene succinate) (PHS) were extensively studied. With respect to PHS, the introduction of a small content of butylene succinate (BS) unit slightly reduces the melting point and equilibrium melting point but hardly influences the glass transition temperature of PHBS. Despite crystallization temperature, PHS and PHBS crystallize through the same crystallization mechanism. At the same crystallization temperature, PHBS crystallizes more slowly than PHS; furthermore, lowering crystallization temperature enhances the crystallization rates of PHBS and PHS. The spherulites morphologies were observed for both of them, with the spherulites nucleation density of the copolymer being smaller than that of the homopolymer. PHBS and PHS share the same crystal structures, indicative of the location of BS unit in the amorphous region.     

Two‐Steps of Gelation System Enhanced the Stability of Syzygium cumini Anthocyanins by Encapsulation with Sodium Alginate,Maltodextrin, Chitosan and Gum Arabic

Journal of Polymers and the Environment - An efficient method based on encapsulation efficiency of Syzygium cumini anthocyanin extract (ANC.E) was established by using a stable concentration from...     

二级膜分离—冷凝—吸附工艺处理石化罐区废气

采用二级膜分离—冷凝—变压吸附工艺回收处理含有高浓度挥发性有机物和苯系物的炼厂罐区外排“呼吸气”。结果表明,进气的非甲烷总烃质量浓度范围41 000~182 000 mg/m³,进气中苯、甲苯和二甲苯的质量浓度分别为400~1 400 mg/m³,150~1 600 mg/m³,300~2 100 mg/m³时,尾气中非甲烷总烃质量浓度始终低于80 mg/m³,去除率均高于99.9%,苯、甲苯和二甲苯的去除率分别为99.6%、99.6%和99.8%。抗冲击负荷实验将进气量提高50%,尾气中非甲烷总烃质量浓度仍低于80 mg/m³。二级膜单元可以高效浓缩轻烃,既回收获得可燃气,又解决了轻烃积累所造成的尾气超标难题。     

Formulation and Characterization of Biodegradable Packaging Film Derived from Potato Starch &; LDPE Grafted with Maleic Anhydride—LDPE Composition

There is a paradigm shift from non renewal resources to renewable resources in view of problems of disposal of plastic products after their life cycle. This paper deals with the approach, preparation and product properties of polymer prepared by using polysaccharide based biodegradable polymer. Basic material has been prepared by mixing LDPE, LDPE-g-mA (LDPE grafted with (0.5%) maleic anhydride (1:1)) containing a polar group in the LDPE backbone. Prepared basic material has been compounded in twin screw extruder with 0, 2.5, 5.0, 7.5, 10.0, 12.5 & 15% of Potato Starch. Thereafter, after conditioning blown film samples were prepared using extrusion film blowing technique, under temperature profile ranging from 120 to 160 °C. Packaging films have been prepared with maximum 15% potato starch contents and have been characterized by FTIR, DSC, TGA, and XRD techniques to ascertain its impact on some structural and thermal properties like thermal stability, flexibility, crystallinity, crystal size etc.     

#x0201c;两酸#x0201d;装置大气污染源分析及治理

石化企业的酸性水汽提装置、酸性干气脱硫装置和硫磺回收装置统称为#x0201c;两酸#x0201d;装置。对#x0201c;两酸#x0201d;装置所采用的工艺流程进行详细分析,得出#x0201c;两酸#x0201d;装置的有组织排放大气污染物主要为SO₂和NO_x,无组织排放大气污染物主要为H₂S、NH₃、有机硫化物和烃类。无组织排放源集中在各单元反应器、储罐和酸性气管线。针对无组织排放源,从防止逸散和恶臭治理两个方面提出了相应的污染防治措施,并比较了溶剂吸收法、燃烧法、湿法化学吸收法等目前常用的恶臭治理技术的优缺点。     

2&#215;300MW机组石灰石-石膏烟气脱硫吸收塔设计

选用石灰石-石膏工艺对山西某电厂2&#215;300MW机组进行烟气脱硫,对其核心设备吸收塔的本体进行设计计算,并对其中的设备进行了选型。     

加载絮凝—超滤—反渗透组合工艺处理PCB电镀废水

采用加载絮凝—超滤—反渗透组合工艺处理含大量重金属离子的印制电路板（PCB）电镀废水。考察了絮凝污泥回流比和水力条件对加载絮凝效果的影响,确定了最佳工艺参数：在加碱沉淀pH 10.5、混凝pH 9.0、PAC投加量10 mg/L、PAM投加量1.0 mg/L的条件下,污泥回流比为47%,加碱沉淀、混凝、絮凝的搅拌转速分别为250,150,50 r/min,搅拌时间分别为6,8,4 min。中试结果表明：经加载絮凝预处理后,总铜、总镍和浊度的平均去除率分别为99.4%、99.3%和93.1%;预处理出水经超滤—反渗透系统处理后,出水水质全部达标。     

缺氧—好氧—催化臭氧氧化工艺处理石化厂含盐废水

采用缺氧—好氧—催化臭氧氧化工艺处理某石化厂的含盐废水。实验结果表明：在进水COD为200~350 mg/L的条件下,经生化处理后的出水COD稳定在50~60 mg/L,COD去除率稳定在75%左右;在臭氧投加量为4.5 g/L、V（催化剂Ⅱ）∶V（废水）=1.5∶1的条件下,进行连续催化臭氧氧化后出水COD稳定在20 mg/L以下,COD去除率大于70%,满足DB 61/224—2011《黄河流域（陕西段）污水综合排放标准》。表征结果显示,催化剂表面含有铜元素,比表面积为250.815 m²/g,吸水率为60.9%,经过滤可去除废水中残留的催化剂。     

煤化工企业高盐废水的“零排放”技术

采用“混凝沉淀-微滤-组合反渗透”工艺对某煤化工企业的高盐废水进行浓缩处理,浓水通过蒸发结晶进行脱水,产水采用常规反渗透进行水回收。运行结果表明,经30 d运行,水回收率保持在85%以上,脱盐率稳定在95%以上,常规反渗透产水水质稳定,产水电导率、浊度、Cl^-质量浓度和COD的平均值分别为12.5 μs/cm,0.1 NTU,7.8 mg/L,1.8 mg/L,满足《炼化企业节水减排考核指标与回用水质控制指标》（Q/SH0104-2007）中污水回用于循环冷却水的水质指标和设计产水水质要求,实现了废水的近“零排放”。     

絮凝#x02014;微波辐射#x02014;Fenton试剂氧化法深度处理焦化废水

用絮凝#x02014;微波辐射#x02014;Fenton试剂氧化法深度处理焦化废水,研究了微波辐射时间、微波功率、FeSO₄加入量、H₂O₂加入量和废水pH对废水处理效果的影响。实验结果表明：在聚合氯化铝加入量为350mg/L、聚丙烯酰胺加入量为12mg/L、废水pH=5、FeSO₄加入量为250mg/L、H₂O₂总加入量为1400mg/L、H₂O₂分3次投加、微波功率为400W、微波辐射时间为60min的条件下,处理后出水的浊度、色度和COD去除率分别为98.59%,97.62%,86.21%。处理后出水澄清透明,COD为50.34mg/L,满足GB50050#x02014;2007《工业循环冷却水处理设计规范》的要求。     

微电解—Fenton氧化—絮凝组合工艺处理油田压裂废水

采用微电解—Fenton氧化—絮凝组合工艺处理油田压裂废水,优化了工艺条件。实验结果表明：最佳工艺条件为初始废水pH 3.0、铁屑加入量1.5 g/L（铁屑与活性炭的质量比1∶1）、微电解时间80 min、Fenton氧化时间120 min、H₂O₂加入量940 mg/L,阳离子聚丙烯酰胺加入量120 mg/L;在最佳工艺条件下处理废水后,COD由3 116.0 mg/L降至681.3 mg/L,总COD去除率达78.1%,3个工段的COD去除率依次为33.1%,37.9%,7.1%,出水水质满足现场回注标准（SY/T 5329—2012《碎屑岩油藏注水水质推荐指标及分析方法》）;该组合工艺对废水的处理效果远优于单独微电解、Fenton氧化或絮凝工艺,且方法简单易行、药剂利用率高。