Ingestion and egestion of microplastic by aquatic insects in Egypt wastewater

Microplastics (MPs) are frequently regarded as environmental and biota contaminants. Yet, research on the accumulation of MPs in living entities, particularly aquatic insects that serve as food resources in the aquatic food chain, is limited. This study to investigate the accumulation of MPs in aquatic insects from water and sediment in an Egyptian wastewater basin. Four typical freshwater insect groups were used. The highest MP load per gram wet weight was reported by collector-gatherers (Chironomus sp. and Hydrophilus sp.), followed by collector-filterers (Culex sp.) with the second highest MP load. However, Predators (Aeshna sp.) had the lowest values. Also, the present results showed a reduction in the number of MPs in all insect taxa tested after a 24 h depuration time, with differences in the observed egestion ability. The mean number of MPs per individual significantly reduced after 24 h in both Chironomus sp. and Culex sp. larvae, where 53% and 40% of MPs particles were ejected from them, respectively. However, the ability of MP egestion decreases in Aeshna sp. nymph (25%), and the lowest proportion of ejection was observed in Hydrophilus sp. adults (9%). Polyethylene terephthalate fibers were the most abundant type of MP in both sediment and water, followed by fragments (polyethylene and polypropylene). Yet, only polyester fibers were detected in the various insect species. The average length of fibers in the various insects was somewhat shorter than in the surrounding environment. The current study reveals that MP ingestion by aquatic insects is not always related to levels of pollution in the environment, since other factors such as feeding strategies may play a role in MP ingestion. Based on these observations, further studies should be carried out on studies on toxicological impacts of MPs on freshwater/aquatic biota.     

Optimization of the recovery of plastics for recycling by density media separation cyclones

Material recovery processes are presented as the optimum option for recycling plastic wastes as a means of recovering hydrocarbon resources. There exist a large variety of automated material recovery processes for recycling of such wastes but each with significant limitations. Of these, the separation based on differences in densities is advocated as the optimum process either for producing recycled products or preparing wastes for subsequent recovery processing.Density separation processes based on cyclone type density media separation (DMS) is presented as an important, potential method for increasing plastics recycling process capacities. It is demonstrated to have the capacity to separate a significantly larger range of particle sizes than those presently processed industrially. The mathematical relationship for the prediction of quality of typical LARCODEMS type density media separations by particle size and density as expressed by the Ecart Probable is presented.A proposed device configuration is presented for density media separation to optimize the recovery and purity of both density fractions produced. It is also suggested that to be economically viable, a large scale of operation is required for industrial plastics recycling operations recovering and producing a number of different plastics with a purity to be used as a substitute for virgin material.     

Application of a Second-Order Kinetic Model to a Complex Melt Polymerization Reaction

A novel copolymer system has been synthesized using methyl hydroquinone diacetate (MHQDA), 1,4 naphthalene dicarboxylic acid (1,4 NDCA), and polybutylene terephthalate (PBT) using the melt polymerization technique. The optimum kinetic parameters pertinent to this system are reported in this study. A simple second-order reaction sequence summarizes catalyzed and uncatalyzed reactions between MHQDA, 1,4 NDCA, and PBT. The kinetic parameters for the copolymerization reaction were determined using a new second-order model. This technique was used to compute the moles of acetic acid generated in the polymerization process. The model was compared to that of the experimentally determined data. Close comparison (percentage error of less than 5%) was obtained between the experimental and theoretical data. The kinetic data support block copolyester formation. The thermal data also supports formation of block polymers.     

离聚物（MPET）对水中铬离子的吸附性能研究

研究了离聚物（MPET）粉末对Cr^3 的吸附性能，探讨了不同的吸附温度、时间、pH值和不同的初始浓度对吸附性能的影响，实验发现Cr^3 在较低温度下和pH为4时能被MPETO分末很好地吸附，最大饱和吸附量为11.80mg/g，实验表明MPET废纤维很可能发展成为一种经济的吸附重金属离子的材料。     

聚对苯二甲酸乙二醇酯废料的回收方法

介绍了聚对苯二甲酸乙二醇酯传统的化学回收方法：甲醇醇解法、水解法和醣酵解法；简述了聚酯新的回收工艺：伊斯曼乙二醇水解工艺、超临界水水解工艺和Reco-PET工艺，及有关国家聚酯回收的工业化实践，并对聚酯回收的前景及影响聚酯回收的因素进行了分析。     

Development of inherent safety and health index for formulated product design

The numerous formulated products which are introduced to the market consist of chemical ingredients that may cause various safety and health hazards to the consumers. Therefore, it is extremely important to practice a systematic methodology to formulate products with acceptable safety and health performances. This work presents an index-based methodology to assess the safety and health hazards of the ingredients during the early formulation stage of product design. Hence, new inherent safety and health sub-indexes are introduced to improve the current safety and health hazards that are needed in formulated product design. The inherent safety and health sub-indexes are assigned with scores based on the degree of potential hazards. A higher score indicates a higher safety risk or severe health effect, and vice versa. The proposed methodology will greatly assist the users to identify the adverse safety and health effects caused by the ingredients. Hence, it is pivotal to eliminate or reduce the safety and health impacts from product usage. A case study on common ingredients used in the formulation of paint is presented on this study to describe the proposed method.     

催化燃烧法处理聚对苯二甲酸乙二醇酯生产废气

采用催化燃烧法处理聚对苯二甲酸乙二醇酯生产过程排放的含乙醛、2-甲基-1，3-二氧戊烷、乙二醇的废气，用进口Pt Pd／Al2O3-CeO2球状催化剂作废气催化燃烧的催化剂。在催化燃烧反应器床层空速为20000h^-1、催化剂用量为935mL、反应器入口温度为250℃、进口废气总烃质量浓度为2555～5099mg／m^3的条件下，处理后废气的总烃质量浓度为1～38mg／m^3，远低于120mg/m^3的国家排放标准，且总烃去除率达到98．6％～100％，乙醛质量浓度小于99mg／m^3,低于125mg／m^3的国家排放标准。     

治理技术邻苯二甲酸二辛酯废水的处理

采用压滤-刮油-中和吸附-压滤-吸附工艺处理邻苯二甲酸二辛酯废水,对处理工艺的运行条件进行了探讨.出水COD和石油类的去除率分别达到97.7%和99.8%.该法设备简单、投资少、操作方便,对排放量较小的邻苯二甲酸二辛酯废水的处理是行之有效的方法.     

对苯二甲酸和聚脂生产废水处理技术综述

对苯二甲酸和聚脂均是化纤工业中的重要原料，本文论述了对这两种生产废水的处理技术，并比较了不同处理方法的优缺点。     

废聚酯醇解条件的研究

研究了废PET(聚对苯二甲酸乙二醇酯)的醇解条件对产物的羟值及平均分子量的影响，表明在196～198℃时，m(乙二醇)，m(PET)=2，催化剂醋酸锌用量为PET质量的1％，醇解3～3．5h，聚酯PET降解很彻底，产物羟值(以KOH计)可达368ms／g以上，平均分子量在305以下，主要成分是对苯二甲酸二乙二醇酯(BHET)单体及其低聚物。DSC和IR验证了产物的组成。