Toxicological and Life-Cycle Perspectives on Waste-Derived Nanoparticles

Many nanoparticles have been created over the last few decades using a variety of techniques and used to develop environmental technology, including water treatment, the detection of persistent contaminants, and soil and water remediation. The studies of alternative inputs for nanoparticle production as well as the use of green synthesis techniques are driven by the field of materials science and engineering’s growing interest in increasing the sustainability of the processes involved in their production. In this paper, we begin by providing an overview of the fundamental principles of producing nanoparticles from different sources, such as plastic, electronic, metal, and industrial waste. We elaborate on key facts of waste identification as a workable input for the treatment and recovery of metal and carbon-based nanoparticles. We next go over several controlling factors that play a role in creating nanoparticles, pointing out probable conclusions as we go. Then, we show some instances of waste-derived nanoparticles used in a proof-of-concept experiment of technology for applications in water quality and safety. Before scaling up production and implementing waste-derived nanoparticles, there are several present problems from the toxicological and life-cycle perspectives that must be taken into account.

Impact of Electronic Wastes Recycling on Environmental Quality

Objective To evaluate the environmental quality of Guiyu, Guangdong impacted by the electronic waste recycling industry. Methods The surface water, ground water and sediment samples taken separately from two sites that recycle E-wastes and other rubbish relevant to the E-waste recycling, and an agricultural area, were analyzed, and the data were used to evaluate the impact of E-waste recycling on the environmental quality of Guiyu based on environmental quality standards in China. Results The concentrations of lead and iron in the surface water samples significantly different in the three locations. The maximum value of lead in the first site was 8 times higher than the threshold of environmental quality standards for surface water. The concentration of iron in polluted sample was 22 times that of the background sample. Manganese and iron also showed a significant difference in ground water samples between the three sites. The amount of iron was 22 times that of the threshold of the quality standard for ground water, and 120 times that of the background sample. Moreover, the results of all the eight heavy metals showed significant differences among the sediment samples. The concentrations of copper, cadmium, nickel, and lead in the polluted samples were above the median benchmarks of National Oceanic and Atmospheric Administration （NOAA）. The copper concentration of 2670 mg/kg was 10 times that of the median benchmark. Conclusion E-waste recycling has led to the severe pollution Guiyu.

Review of Soil Environmental Contamination Caused by Heavy Metals from Electronic Wastes

The reports about soil environmental contamination from heavy metals in electronic wastes were reviewed. The production, sources and disposition of electronic wastes were introduced. The negative impacts of electronic wastes on the environment were analyzed, and soil pollution from electronic wastes in several typical districts were discussed and summarized.

Efficiency of Crude α-Cyclodextrin in Gold Recovery from Electronic Waste and Soil

In this study, the metal coordination ability of alpha-cyclodextrin (α-CD) was employed to complex gold and thus isolate and extract it from different matrices of acid-digests of electronic waste and soil. The crude α-CD used was extracted from cassava and yam starch of the non-edible plant species using E. coli α-cyclodextrin glucanotransferase (α-CGTase), with yields ≥ 62%. The reaction was monitored progressively by ultraviolet-visible spectroscopy and checked with infrared spectroscopy (IR) for the presence of α-CD. The crude α-CD extract without need for purification was refluxed with gold containing-electronic waste and soil predigested in a mixture of NaBr/HNO3 for 4 - 7 days. Recoveries of up to 22.9% and 70.8% gold were achieved from electronic waste and soil, respectively using 0.1 M α-CD. This approach is cheap, effective, and environmentally benign.

Selective Adsorption of Ag(I) from Electronic Waste Leachate Using Modified Silk Sericin

A novel biosorbent was synthesized by grafting bisthiourea(BTU)on a silk sericin(SS)matrix.This biosorbent was denoted as BTU-SS and characterized by Fourier transform infrared spectroscopy(FTIR),zeta potential measurements,elemental analysis,and X-ray photoelectron spectroscopy(XPS).As revealed by the adsorption experiments,both BTU-SS and SS showed low affinity towards coexisting base metallic ions in Ag(I)-Cu(II)-Zn(II)-Ni(II)-Pb(II)electronic waste leachate mixtures,while their adsorption capacities towards Ag(I)reached 30.5 and 10.4 mg∙g-1 at a pH of 5.0,respectively.BTU-SS showed higher selectivity towards Ag(I)than SS,as revealed by the Ag(I)partition coefficients between the biosorbents and the leachate(16634.6 and 403.3,respectively).As further demonstrated by column experiments,BTU-SS allowed the separation of Ag(I)from an electronic waste leachate.Thermodynamic studies showed that the adsorption of Ag(I)was exothermic and spontaneous,while adsorption kinetic experiments revealed that chemisorption dominated the adsorption process with activation energies of 47.67 and 53.27 kJ∙mol-1 for BTU-SS and SS,respectively.FTIR and XPS analyses of fresh and Ag(I)-loaded BTU-SS further revealed an adsorption mechanism mainly involving electrostatic and coordination interactions.

Interference-Free Determination of REEs in Electronic Waste Using ICP Optical Emission Spectroscopy

Recently, the demand for REEs （rare earth elements） has been heavily increasing, as they are used in many high-tech products （e.g., because of their specific magnetic behavior）. As a result, the supply situation for REEs is worsening and the world market is depending on Chinese exports, so that it may be worthwhile to recycle e-waste （electronic waste） in European countries. This article describes an analytical method to analyze REEs in different kinds of e-waste with the help of a simultaneous ICP-OES （ICP optical emission spectrometer）. The task is challenging because samples show significant differences in terms of major, minor and trace element concentrations. Depending on the field of application, the level of matrix elements and target elements differs completely, resulting in a wide variety of spectral interferences. The method presented in this article allows an accurate quantification of REEs as well as a high sample throughput. In addition to REEs, other elements of economic interest can be determined in the same way. The development of a sample preparation process is another important issue and considered as well.

A study of factors influencing consumers' behavior in recycling waste household electronic appliances

The innovation of technologzv and the improvement of people＇s living standard accelerate the replacement of consumer electronic appliances, resulting in a significant increase of waste household electronic appliances （WHEA）. To address the environmental problems of WHEA, many countries have enacted legislation according to WHEA management, including collecting, processing and recycling. The regulations on the management of WHEA were also drafted in China and pilot programs of WHEA recycling management encountered difficulties in collecting WHEA. The success of a recycling scheme is dependent on people＇s willingness of participating in the scheme, This paper applies Ajzen＇s theory of planned behavior to seek the main factors to engourage consumers to participate in WHEA recycling management in China. Data from a survey conducted with a sample of 633 consumers show that service motivation is the first predictor of participation behavior intention, followed by environmental behavior attitude, economic motivation, subjective norm. and perceived behavior barrier. Environmental knowledge is found not to be the predictor of behavior intention in this recycling scheme. Study results also suggest that publicity is the key situational factor in the WHEA recycling management. Recycling network and policy have little influence on changing consumers＇ current behavior intention and participation. Implications of the findings are discussed and future research directions are suggested in the end.

Recycling of Electronic Waste, Using Basic and Acid Leaching

This recycling of printed circuit board (TCI) for the production of metals, given the environmental degradation that can cause toxic substances of these, is the reuse of valuable materials recovered from the TCI, this being an economic engine that promotes the recycling of this waste. This paper presents a methodology for evaluating the reaction kinetics and leaching of metals that form the metal substrate, which have environmental and energy advantages, so the generation of new recovery techniques metals from the TCI low environmental and energy impact is increasingly necessary, for it is essential to establish the parameters affecting the reaction rate and identify design alternatives to determine whether or not sustainable, economically viable and that does not pollute. The method adopted was a leaching acid samples, where the full factorial method employed two experimental levels to evaluate the influence of: leaching time, temperature of the aqueous leach solution, reaction kinetics and solid/liquid, on the percentage of metal extraction. Subsequently, the metals are obtained by calcining and smelting the resulting salts by addition of acid liquor.

Effect of Partial Replacement of Coarse Aggregate with Electronic Waste Plastic in Light Weight Concrete

This study assessed the usefulness of the replacement of coarse aggregate partially with electronic waste(e-waste)plastic in lightweight concrete since developing countries have been challenged with management of e-waste as well as high cost of coarse aggregates for concrete production.Coarse aggregates were replaced with e-waste plastic in concrete at 5%,10%,15%,and 20% for a concrete class of C20.The particle size distribution of the e-waste plastic aggregates was determined as well as the slump,compressive strength,water absorption and bulk density of the concrete.Generally,the slump decreased as the e-waste increased.The compressive strengths decreased for the 5%and 10%replacement of coarse aggregates with e-waste but increased for the 15% and 20% replacement of coarse aggregate with e-waste.0% water absorption was obtained for the 15% and 20% e-waste content while the 10%e-waste concrete obtained 0.01% and the 5% e-waste obtaining of 0.013% after 28days of curing.The densities of 5%,10%,15% and 20% e-waste plastic content decreased as compared to the 0% e-waste plastic content.The values of compressive strength obtained showed that coarse aggregate replacements by e-waste plastic at 15% and 20% may be appropriate for lightweight concrete of class C20/25 since compressive strengths ranged between 16.09 Nmm^(-2) and 22.87 Nmm^(-2).This implies that partial replacement of coarse aggregate with e-waste plastic may be useful for lightweight concrete as well as helping in eradicating the environment of the menace of e-waste plastic.

Electrical and Electronic Waste in Northwest Mexico

The waste derived from Electrical and Electronic Equipment (WEEE) is of interest now worldwide, in some countries due to the rapid technological development and in others due to technological dependence through the acquisition of second hand equipment. Therefore it is necessary to implement strategies for the sustainable management of electrical and electronic equipment at the end of its useful life. This paper presents the results of an investigation that was conducted in a city located in the Northwest of Mexico, which seeks to understand the management practices of household WEEE generators. A survey was applied to a representative sample of the population with a confidence level of 90%. Six home appliances were quantified and it was found that approximately 21% of them are disposed directly as part of the household flow of Municipal Solid Waste (MSW), while 79% are storage for a latter sale, repair or reuse. The results obtained support the need to develop evaluations and to implement possible scenarios for the sustainable management of Electrical and Electronic Waste.

Companies’ E-waste Estimation Based on General Equilibrium The­ory Context and Random Forest Regression Algorithm in Cameroon: Case Study of SMEs Implementing ISO 14001:2015

Given the challenge of estimating or calculating quantities of waste electrical and electronic equipment(WEEE)in developing countries,this article focuses on predicting the WEEE generated by Cameroonian small and medium enterprises(SMEs)that are engaged in ISO 14001:2015 initiatives and consume electrical and electronic equipment(EEE)to enhance their performance and profitability.The methodology employed an exploratory approach involving the application of general equilibrium theory(GET)to contextualize the study and generate relevant parameters for deploying the random forest regression learning algorithm for predictions.Machine learning was applied to 80%of the samples for training,while simulation was conducted on the remaining 20%of samples based on quantities of EEE utilized over a specific period,utilization rates,repair rates,and average lifespans.The results demonstrate that the model’s predicted values are significantly close to the actual quantities of generated WEEE,and the model’s performance was evaluated using the mean squared error(MSE)and yielding satisfactory results.Based on this model,both companies and stakeholders can set realistic objectives for managing companies’WEEE,fostering sustainable socio-environmental practices.

基于O2O的乡镇电子废弃物回收机制研究

目前世界上增长速度最快的固体废弃物种类是电子废弃物,大量的电子废弃物若处理不当将严重威胁我国生态环境和美丽中国建设质量。电子废弃物回收处理中回收是关键,“O2O电商+回收”已成为电子废弃物回收发展新模式。分析发现:由于城乡居民在收入、观念等方面存在差异,部分乡镇已成为电子废弃物的主要集散地;并在其回收过程中普遍存在回收意识薄弱、回收站混乱、回收处理技术不完善等问题。研究认为:O2O电商模式可将线上线下相互融合,实现电子废弃物多主体积极互动,共同构成一个完整的电子废弃物回收体系。同时,结合我国乡镇居民、地域、基础设施及技术条件等方面的特征,从融合、激励、引导和监督四个方面提出O2O模式下乡镇电子废弃物生态化处理的回收机制。

多主体参与的废弃电器电子产品回收治理演化博弈研究

当前私自拆解电子垃圾的事件并不鲜见,单一的政府治理模式难以实现有效治理废弃电器电子废弃物的目标,鉴于社会共治在诸多公共问题治理的成功实践,引入社会共治理念,对政府和公众共同参与废弃电器电子废弃物治理的治理模式进行研究。基于博弈论,构建政府、回收经营者、公众三方演化博弈模型,通过求解平衡点并分析平衡点的稳定状态,得出达到稳定点的稳定策略,并进行数值仿真分析参数变化对稳定策略的影响,据此给出强化企业声誉意识、完善奖惩机制、搭建便捷渠道降低公众成本等相关治理建议。

基于优化度量学习算法的电子元件智能分栋系统的实现

当今社会电子产品的更新迭代速度加快,造成大量电子废弃物,为避免资源浪费,回收可重复利用的电子元件的分栋工作变得日益重要。传统的分栋方法效率低并易受人为因素的影响。现开发一种基于优化度量学习算法的电子元件智能分栋系统。该系统引用核分类器改进优化度量学习模型,可提高电子元件识别效率和精度,能充分挖掘电子废弃物中可回收利用价值,并带来巨大的循环经济效益。

基于资源池视角的废弃电子产品逆向物流系统协同模型研究

废弃电子产品具有双重属性,其逆向物流网络分布范围广并且数量增长迅速。不同主体对废弃电子产品逆向物流的需求是不同的,单个的逆向物流节点很难同时满足不同需求,如何合理高效地协调各个逆向物流节点的资源,以满足各个逆向物流任务是亟待解决的重要问题。在数字技术的支持下,逆向物流信息协同领域得到丰富和完善,针对传统模式中废弃电子产品回收处理过程存在的资源利用率低、浪费严重等情况,将整个逆向物流网络看作资源池,采用智能体(Agent)处理功能网络的任务迁移模式代替传统方法中大量的数据迁移模式,构建了基于多智能体(Multi-Agent)的废弃电子产品逆向物流系统资源协同模型,最后仿真结果验证了所建模型的有效性和可行性,为废弃电子产品逆向物流系统的资源调度分配提供了新的解决方案。

废弃电器电子产品回收与处理体系研究及建议

随着全球电器电子产品的快速更新和迭代,电器电子产品呈现出生命周期缩短的新趋势。废弃电器电子产品(WEEE)对全球生态环境构成巨大威胁,解决这一问题势在必行,各国政府纷纷制定了相应的法律法规来应对这一挑战。首先,对世界各地区主要国家的法规建设情况进行了系统梳理;然后,对我国当前WEEE行业的发展现状进行分析并提出了发展中存在的问题;最后,从加快生产者责任延伸制度深化推广、提升正规回收企业的市场竞争力和加强WEEE相关技术能力3个方面提出了发展意见,以期为我国WEEE行业的发展提供一定的指导。

电子废弃物资源化回收冶炼炉渣危险特性研究

废电路板有色金属资源化回收利用过程中,会产生大量冶炼炉渣。针对《国家危险废物名录》(2021年版)实施后有色金属资源化回收冶炼炉渣的下一步安全处置方式、危险特性不明等问题,选取国内某典型电子危险废物治理企业富氧侧吹冶炼炉渣为研究对象,通过采集100个样品进行元素种类和腐蚀性、毒性特性测试,得出该冶炼炉渣不具有危险废物鉴别标准规定的危险特性,可按照一般工业固体废物进行管理的结论。该结论有助于冶炼炉渣的危险特性判断和环境监管,也为冶炼炉渣类无害化处理和资源化利用提供了技术指导。

改善剩余污泥厌氧消化产甲烷性能的新策略:导电材料介导微生物种间直接电子传递

综述了近年来关于碳基和铁基导电材料促进DIET产甲烷的研究进展,归纳了直接种间电子传递的机制,总结了碳基和铁基导电材料的结构特征、电子传递机理和强化剩余污泥厌氧产甲烷效果。指出了当前研究存在的不足,并对未来的研究方向做出了展望。

基于危害性评价的危险废物分级方法研究——以电子行业为例

为解决不同危险特性之间的风险比较及探索危险废物的分级分类管理问题,将危险废物中的有毒有害物质作为风险物质,参考GB 18218—2018《危险化学品重大危险源辨识》和HJ 941—2018《企业突发环境事件风险分级方法》中风险源评价方法中临界量的概念,提出危险废物危害值和危害率的概念,将危险废物的危害性定量化,建立危险废物分级方法,对危险废物及产废企业进行分级。对北京市5家电子行业企业的7种危险废物进行采样检测,并按建立的方法进行评价,结果表明:采集的危险废物涉及易燃性、腐蚀性、毒性,危害率从高到低分别为具有易燃性、腐蚀性、毒性的危险废物;废有机溶剂与酸洗废液的危害值较高;企业的危险废物危害值从大到小依次为A(6.13)、B(2.12)、C(1.23)、E(1.20)、D(0.82)。研究显示,危害率可以区分危险废物自身的固有危害,可作为危险废物分级的指标,比较不同危险特性废物的风险;危害值可作为企业危险废物分级管理的参考。

电子垃圾热解技术研究进展

总结了印刷电路板、钽电容、锂离子电池、发光二极管和液晶显示器等重要电子垃圾的组成特性。论述了常压热解、共热解、催化热解、真空热解、微波辅助热解和等离子体热解法处理电子垃圾的研究与应用进展,对比分析了各类方法的优缺点。指明电子垃圾热解技术存在的挑战并对未来的发展方向进行了展望。