Influence of Fibers on the Mechanical Properties of Cassava Starch Foams

The utilization of renewable resources in packaging can provide solutions to ecological problems such as waste quantity. Agricultural resources are alternative raw materials, among which there is starch, a natural polysaccharide that can be used to form resistant foam under wet and warm conditions. The starch foam is obtained by thermo pressing process where cassava starch, water and additives are processed to form a rigid structure by swelling, gelatinization and network formation. Natural fibers can be used to improve the mechanical properties of starch foams. In this project was investigated the influence of the addition of fibers in the levels of 1, 2 and 3% of cassava (short fiber) and 1, 2 and 3% of wheat fiber (powered fiber) in the starch dough. The foams were characterized by physical methods of strength, flexibility, density and by Scanning Electron Microscopy (SEM). The increase in fibers quantity has resulted in foams with higher density and less flexibility, whatever the fiber type. Most fibers quantity did not improve the foam strength. Foam made with 1% of cassava fiber showed higher compression strength; by increasing the percentage quantity there was a decrease on the compression resistance. Foam made with wheat fiber presented a lower result in 2%. The fiber type had no statistical significance in strength, flexibility and density foam. Only the fiber quantity was significant. The results showed that both fibers presented limited dimensions to improve the reinforcement of the starch foams up to 1%.     

Catalytic upgrading of higher 1-alkenes from polyethylene thermal cracking by modified Wacker oxidation

The economic success of feedstock recycling procedures for plastic wastes is increasingly demanding the conversion of the starting residue into more valuable chemicals. Thermal cracking of polyethylenes leads to the preparation of equimolar mixtures of n-paraffins and 1-alkenes within the C₂–C₁₀₀ range. These 1-olefins can be catalytically upgraded by selective oxidation processes to more valuable products (e.g., ketones and fatty acids) with different uses such as polar waxes, cetane improvers, varnishes, and printer inks. The results obtained on oxidation in a modified Wacker system of a model 1-olefin (1-dodecene) as well as of a distillate cut (C₁₀–C₂₅) of the product from the thermal cracking of urban polyethylene waste are described.     

Current scenario and challenges of plastic pollution in Bangladesh: a focus on farmlands and terrestrial ecosystems

● A global snapshot of plastic waste generation and disposal is analysed. ● Effect of plastic pollution on environment and terrestrial ecosystem is reviewed. ● Ecotoxicity and food security from plastic pollution is discussed. Plastic is considered one of the most indispensable commodities in our daily life. At the end of life, the huge ever-growing pile of plastic waste (PW) causes serious concerns for our environment, including agricultural farmlands, groundwater quality, marine and land ecosystems, food toxicity and human health hazards. Lack of proper infrastructure, financial backup, and technological advancement turn this hazardous waste plastic management into a serious threat to developing countries, especially for Bangladesh. A comprehensive review of PW generation and its consequences on environment in both global and Bangladesh contexts is presented. The dispersion routes of PW from different sources in different forms (microplastic, macroplastic, nanoplastic) and its adverse effect on agriculture, marine life and terrestrial ecosystems are illustrated in this work. The key challenges to mitigate PW pollution and tackle down the climate change issue is discussed in this work. Moreover, way forward toward the design and implementation of proper PW management strategies are highlighted in this study.     

基于LCA的商品包装合理性模糊评价方法研究

文章采用环境工程学的生命周期评价法从包装产品的功能实用性、环境协调性、经济适用性三个影响因素出发,建立了递阶层次结构的评价指标体系,并利用层次分析法对评价指标体系中不同的指标赋予了权重;同时在此基础上提出了对包装合理性进行评价的模糊综合评价方法,并给出了实例分析。结果表明:采用LCA的模糊综合评价法对包装合理性进行评价可以综合考虑环境、经济和功能三方面因素的影响,可以建立起系统全面的评价指标体系,从而得到客观公正的评价结果。采用这种方法对包装合理性进行评价时,评价过程简单易行,可操作性强,还可以为包装合理性的改善提供方向和建议,具有较强的社会意义和实际意义,同时这也表明了其在包装合理性评价中的可行性。     

包装垃圾的分类与回收利用

包装垃圾是由废弃的包装物产生的固体垃圾,约占我国城市生活垃圾的1/3,虽然政府进行了必要回收,但仍有1/3以上的塑料、玻璃等包装物没能被有效回收利用,成了填埋场的主要填埋物,造成了环境污染和土地、石油等不可再生资源大量浪费。从回收利用和源头减量两方面提出包装垃圾的应对,一是对包装垃圾按来源、成分等进行详细分类,并建议回收处置方法;二是从制定行业政策方面来减少过度包装和扶持再生资源行业健康发展,有效处置包装垃圾等可再生资源。     

Assessing contamination of smoked sprats (Sprattus sprattus) with polycyclic aromatic hydrocarbons (PAHs) and changes in its level during storage in various types of packaging

The analysis of material used in this study demonstrated that the amount of polycyclic aromatic hydrocarbons (PAHs) in smoked sprats varies from the level below the lowest detection limit in muscles up to 9.99 µg kg^?1 of benzo[a]pyrene (BaP) in fish skin. Such a high level of PAHs in skin was reported only in one of six batches of sprats, while mean BaP level was at 1.69 µg kg^?1. Regardless such a high BaP level in skin, its concentration in muscles did not exceed the maximum acceptable level. The study objective was to assess to what extent packaging materials adsorb PAH compounds from food. Changes in the PAH levels were monitored in fish during their storage in packages made of various materials. The storage time was from 0 to 168 hours. The obtained results varied considerably, therefore their scatter did not allow to confirm unequivocally the preliminary hypothesis about the reduction of PAHs due to their migration to packaging material. However, analysis of the packaging used in this study demonstrated a significant increase in the level of total 16 PAHs. When high-density polyethylene (HDPE) packaging was analysed, a six-fold increase in the total 16 PAHs was observed comparing to the blank sample.     

分离剂甲酸溶液浓度和温度对于铝塑湿法分离的影响研究

主要针对无菌复合包装废弃物中去除了纸浆后的铝塑部分的湿法分离工艺进行研究,选用甲酸作为分离溶剂,分析其反应机理。并着重对分离过程的影响控制因素进行实验研究,就不同的分离剂浓度、不同反应温度以及不同液固比条件下铝塑分离的效果及反应速率的变化分别进行分析研究,寻找铝塑片分离各影响因素之间的关系,为工业化生产应用提供参考,以提高无菌复合包装废弃物的再生利用率。     

Persistent organic pollutants in plastic marine debris found on beaches in San Diego, California

Plastic debris were collected from eight beaches around San Diego County, California. Debris collected include: pre-production pellets and post-consumer plastics including fragments, polystyrene (PS) foam, and rubber. A total of n = 2453 pieces were collected ranging from <5 mm to 50 mm in size. The plastic pieces were separated by type, location, and appearance and analyzed for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and its breakdown products, and chlordanes. PAH concentrations ranged from 30 ng g⁻¹ to 1900 ng g⁻¹, PCBs from non-detect to 47 ng g⁻¹, chlordanes from 1.8 ng g⁻¹ to 60 ng g⁻¹, and DDTs from non-detect to 76 ng g⁻¹. Consistently higher PAH concentrations found in PS foam samples (300-1900 ng g⁻¹) led us to examine unexposed PS foam packaging materials and PS virgin pellets. Unexposed PS foam contained higher concentrations of PAHs (240-1700 ng g⁻¹) than PS virgin pellets (12-15 ng g⁻¹), suggesting that PAHs may be produced during manufacturing. Temporal trends of debris were investigated at one site, Ocean Beach, where storm events and beach maintenance were found to be important variables influencing debris present at a given time.     

Persistence,Distribution, and Emission of Telone C35 Injected into a Florida Sandy Soil as Affected by Moisture,Organic Matter,and Plastic Film Cover

Abstract

With the phase-out of methyl bromide scheduled for 2005, alternative fumigants are being sought. This study of Telone C35, a mixture of (Z)- and (E)-1,3-dichloropropene (1,3-D) with chloropicirin (CP), focuses on its emissions, distribution, and persistence in Florida sandy soil in microplots with different soil–water and organic matter carbon (C) content with and without two different plastic film mulches. The addition of CP did not affect the physical behavior of the isomers of 1,3-D. Slower subsurface dispersion and longer residence time of the mixed fumigant occurred at higher water content. An increase in the percent organic carbon in the soil led to a more rapid decrease for chloropicirin than for 1,3-dichloropene isomers. The use of a virtually impermeable film (VIF) for soil cover provided a more even distribution and longer persistence under all the conditions studied in comparison to polyethylene (PE) film cover or no cover. The conditions of near field capacity water content, low organic matter, and a virtually impermeable film cover yielded optimum conditions for the distribution, emission control, and persistence of Telone C35 in a Florida sandy soil.     

Ubiquity of bisphenol A in the atmosphere

Bisphenol A (BPA) is a suspected endocrine disruptor in the environment. However, little is known about its distribution and transport in the atmosphere. Here, the concentrations of BPA in the atmospheric aerosols from urban, rural, marine, and the polar regions were measured using solvent extraction/derivatization and gas chromatography/mass spectrometry technique. The concentrations of BPA (1-17,400 pg m⁻³) ranged over 4 orders of magnitude in the world with a declining trend from the continent (except for the Antarctica) to remote sites. A positive correlation was found between BPA and 1,3,5-triphenylbenzene, a tracer for plastic burning, in urban regions, indicating that the open burning of plastics in domestic waste should be a significant emission source of atmospheric BPA. Our results suggest that the ubiquity of BPA in the atmosphere may raise a requirement for the evaluation of health effects of BPA in order to control its emission sources, for example, from plastic burning.