Waste Mobile Phones Research Articles

Selection of disassembly schemes for multiple types of waste mobile phones based on knowledge reuse and disassembly line balancing

The growing number of waste mobile phones (WMPs) have made recycling an urgent issue. Different disassembly schemes demonstrate varying effectiveness in the large-scale disassembly of WMPs. It is necessary to consider both economic benefits and efficiency improvement comprehensively. This paper applies knowledge reuse and disassembly line balancing to the automated disassembly of multiple types of WMPs. In this regard, descriptive standards for mobile phone disassembly knowledge at different workstations are established based on the theory of knowledge reuse. In light of mobile phone disassembly characteristics, workstation thresholds, threshold intervals, and excessively small thresholds are introduced to improve the selection of disassembly line schemes. Based on a quantitative analysis of disassembly line balancing, the selection schemes for disassembling different batches of phones have been optimized. Case studies are conducted on Android and iOS system smartphones to verify the proposed method. The experimental results demonstrate that our proposed method, which incorporates disassembly knowledge, judgment thresholds, and selection schemes, substantially enhances the accuracy of disassembly line selection. For iOS system phones, designing two lines can disassemble all models of WMPs. For Android system phones, the retirement time of mobile phones influences the selection of lines in the disassembly process. Phones with earlier retirement times are more likely to be selected for simpler disassembly lines. Based on disassembly line balancing, two proposed cases for disassembling different batches of phones increase the overall disassembly efficiency by 48.4 % and 46.7 %, respectively.

Recovery of Copper Layer from Waste Mobile Phone Printed Circuit Board Without Crushing

Resource recovery and material reuse from waste is an art of circular economy. Waste mobile phone printed circuit boards contain a significant amount of nonferrous and precious metals, where copper is one of the dominant nonferrous elements. This paper presents the recovery of copper material using an electrochemical process from three samples of waste mobile phone printed circuit boards, each double-sided, where for sample preparation no crushing and dismantling are applied except that the painting mask is chemically removed. From mass analysis, the gross amount of the recovered copper from the sample materials was 5.94 g and the calculated average was 1.98 g per sample material. In this way, the copper layer from waste mobile phone printed circuit boards could be recovered economically at an early stage, which could reduce complexity and improve further material recovery compared to the traditional crushing practice.

An improved artificial bee colony algorithm for the multi-objective cooperative disassembly sequence optimization problem considering carbon emissions and profit

The disassembly and recycling of electronic waste are essential for realizing residual value, lowering carbon emissions and fostering sustainable development. This article addresses multi-objective cooperative disassembly planning and algorithm optimization for waste mobile phones. The model aims to reduce carbon emissions during the disassembly process and to increase profits. Moreover, an improved artificial bee colony (IABC) algorithm is introduced to address the model. The model is validated using Apple smartphones as a case study. The results indicate that cooperative disassembly can lower carbon emissions by 21.04% and increase profits by 40.04% more than sequential disassembly. The efficiency of the improved algorithm was assessed using Friedman and Nemenyi tests. Significant differences were found between the IABC and the other three algorithms, with significant P-values of P = 0.001, P = 0.006 and P = 0.024. It is demonstrated that the proposed model and improved algorithm exhibit reliability and superiority.

Preference and Willingness to Pay for Waste Mobile Phone Recycling among College Students in Beijing: A Discrete Choice Experiment Study

Preference and Willingness to Pay for Waste Mobile Phone Recycling among College Students in Beijing: A Discrete Choice Experiment Study

Recovery of precious metals from mobile phone waste: Studies on leaching and adsorption by functionalized activated carbon

In today's world, the utilization of electronic devices, particularly mobile phones, has seen a remarkable surge and they are a valuable source of recovery of precious metals. The current study reports on the physical and chemical processing of mobile phone waste into leachate, followed by recovery of precious metals, using ionic liquid functionalized activated carbon (ACF). The recovery process was explored both in batch and column study. The presence of base metals in the final leachate was minimized by employing multi-stage chemical leaching, leading to a more efficient purification process. Moreover, adjustment of HCl concentration in the leachate leads to decreased in other metals interference during adsorption. Following the batch adsorption results, a favorable interaction between IL and metal complexes leads to a quantitative adsorption of the precious metals. In addition, ACF also gave an excellent performance in the column adsorption process with the high bed depth and low flow rate of the leachate as the influential parameter. An increase in the bed depth and a decrease in leachate flow rate proportionally increases the values of kTh (rate constant), qe (adsorption capacity), and KYN (rate constant) and positively increases the 50% breakthrough time (τ). Moreover, the final purification of the adsorbed metals was performed selectively through sequential desorption, employing Na2S2O3, NH4SCN, and HNO3 solutions. Finally, the adsorption capability of ACF shown a negligible change after five repetitive adsorption-desorption cycles. Thus, the current study presents a method to process mobile phone waste and selectively recover the precious metals from the leachate.

Study of the Mechanical Properties of Polyester Based GFRP Composites in E-Waste from Mobile Phones Displays

Everyone now lives in a technologically highly hybridised environment; mobile technology is regarded as one of the most significant of all technologies. Inside the phone is the entire world. This article primarily focuses on recycling e-waste into composites (especially waste from mobile phones). The range of products used for this study included basic and smartphones. The primary product chosen was the display glass from smartphones. With the use of recent literature reviews, the problem was identified. Many studies focused on polyester resins with ceramic powders and their composites. The mobile display powder has been mixed with Polyester resin. The mobile phone display electronic waste (MPDEW), like polyester resin, was cost-effective. Mobile phone waste was used as filler in various proportions including 0, 5 and 10 %. To determine the effect of e-waste with polymer composites, the mechanical properties such as tensile, compression, flexural, and impact were undertaken. The scanning electron microscope was also used for the microstructural analysis.

E-waste by mobile Phones: A Case Study on the Consumption, Disposal Behavior, and Awareness of Consumers in Kolkata, India

Mobile phones, particularly smartphones, have become an indispensable part of our daily lives. Technological advancements and the availability of high-speed internet services have culminated in an enormous rise in the number of mobile phone users. Nowadays, as a result of constant advancements in mobile phone technology and other factors, a portion of consumers use more than one mobile phone. On the other hand, the actual lifespan of a mobile phone has reached nearly 4 years. As a result, mobile phone waste as a component of electronic waste has increased significantly over the last decade. From an environmental point of view, various carcinogenic chemical components may be released from mobile phones during the informal recycling process, drastically polluting our environment. According to our survey, while the majority of educated mobile phone users in Kolkata are aware of the adverse effects of electronic waste (e-waste), they typically choose less expensive and easier disposal solutions since they are not concerned about the recycling of mobile phones or e-waste. This study primarily highlighted mobile phone disposal behaviours in Kolkata, India. After reviewing the results of our questionnaire, we noticed numerous actual problems with customers’ disposal patterns for their obsolete mobile phones. In this article, we attempt to depict the current problem of e-waste generated from mobile phones in Kolkata.

Incorporating self-employed maintainers into WEEE formal recycling system: A system dynamic approach

The establishment and operation of a formal recycling system for waste electrical and electronic equipment is an important measure to reduce environmental hazards and improve the recycling of resources, but how to incorporate self-employed maintainers into the system has formed an important research gap. Based on the perspective of extended producer responsibility, we argue that self-employed maintainers are required to assume the corresponding environmental responsibility for the environmental externality caused by informal maintenance activities. Using qualitative structural analysis techniques of system dynamics approach with quantitative simulation analysis techniques, we construct an incentive model for self-employed maintainers’ participation in formal recycling system, based on which we propose four incentive strategies. A simulation analysis is further conducted by using the case of waste mobile phones recycling in Qingdao to verify the effectiveness of our incentive model and strategies.

ESG Modeling and Prediction Uncertainty of Electronic Waste

Driven by a variety of factors, including the advent of digitalization, increasing population and urbanization, and rapid technological advancements, electronic waste (e-waste) has emerged as the fastest growing waste stream globally. Effective management of e-waste is inherently aligned with environmental, social, and governance (ESG) frameworks and is typically examined within this context. Accurate quantification of the current and future accumulation of e-waste is a key step towards ensuring its proper management. Numerous methodologies have been developed to predict e-waste generation, with the grey modeling approach receiving considerable attention due to its ability to yield meaningful results using relatively small datasets. This study aims to introduce a novel forecasting technique for predicting e-waste, particularly when limited historical data are available. The proposed approach, the non-linear grey Bernoulli model with fractional order accumulation NBGMFO(1,1) enhanced by Particle Swarm Optimization, demonstrates superior accuracy compared to alternative forecasting models. Additionally, the Fourier residual modification method is applied to enhance the precision of the forecast. To provide a practical illustration, a case study utilizing waste mobile phone data from Turkey is presented.

Critical and strategic metals in mobile phones: A detailed characterisation of multigenerational waste mobile phones and the economic drivers for recovery of metal value

Mobile phones have a high embedded value of interest within a circular economy. With the number of these devices operating worldwide expected to reach 18bn by 2025 their low recycling rate leads to large tonnages of End-of-Life Mobile Phones (EoL-MPs) and de facto a challenging waste stream. The rapid replacement of mobile phones to meet consumer demand further compounds the challenges due to increased demand for raw materials, increased energy, and water consumption, and, where uncontrolled and poor disposal at end-of-life occurs, significant impacts on health and the environment.EoL-MPs comprise a complex and heterogeneous combination of materials that include strategically and economically important high technology metals, many of which are classified as critical by the EU. A detailed characterisation of key components (PCBs, casings, screens, cameras, and speakers) of multigenerational (feature phones, multimedia phones, and smartphones) EoL-MPs is studied to determine the potential for recovery of both metal and non-metallic fractions and the economic drivers for recovery of the metal value. On average, the major mass fraction distributed in a mobile phone is: plastics (40%), metals (35%) and ceramics (25%).The results show that 1 tonne of EoL-MPs can contain up to 53 Kg copper, 141 g gold, 270 g silver, 10 g platinum, 18 g palladium and 3.3 Kg rare earth elements, among other valuable metals, with many of these elements found to be at least twice, and in some cases, up to 600 times more concentrated than in their natural ores. The calculated economic value of the EoL-MPs components is in the order: cameras (86,860 US$/ton), printed circuit boards (55,459 US$/ton), speakers (21,853 US$/ton) and screens (3,779 US$/ton). Based on the predicted 5 billion EoL-MPs discarded by the end of 2022, this waste stream has a potential economic value of US$ 9.25 billion. Use of EoL-MPs as a secondary resource-rich stream of these critical materials therefore offers a route to close the materials loop, helps to mitigate the threat to natural resources and the environmental and human health impacts arising from mining operations, relieves supply demands and contributes to the economy.

Evaluation of the recycling potential of obsolete mobile phones through secondary material resources identification: A comprehensive characterization study

The growing concern over the management of e-wastes has generated an interest in the recovery of resources from these wastes under the concept of urban mining and circular economy. However, in the absence of accurate knowledge of the physico-chemical compositional structure of these wastes makes the recycling process difficult. Thus, the present study conducted a recycling-oriented characterization of waste mobile phones (WMPs) for the identification of secondary materials and estimated their recycling potential. The characterization was performed using ICP-OES and FTIR techniques after dismantling WMPs for the determination of elemental composition and the polymeric fractions respectively. Dismantling of the WMPs revealed that enclosures, batteries, display modules, and PCBs consist of 35.33 wt%, 28.9 wt%, 19.44 wt%, and 16.31 wt% respectively. Of these components, PCBs constitute the highest economic recovery potential with an estimated potential revenue generation of more than 50,000 US $ per ton of waste PCBs. Copper showed the highest recovery potential (234.39 tons/year) with an economic value of approximately 3317 US $/ton of WPCBs followed by Sn (27.37 tons/year) and Ni (24.64 tons/year). Among different precious metals, Au was found to have the highest percentage of economic value (76.22%) followed by Pd (8.16%) and Ag (3.13%). The display modules and enclosures were found to have relatively lower contributions than WPCBs in the overall recycling potential due to lower metal contents and mixed polymeric fractions. The findings in the study indicate that WMPs could serve as a promising new source for sustainable secondary mining of rare and valuable metals. Further, the study will help the policymakers in designing effective e-waste management strategies through the promotion of sustainable recovery of materials.

Research on the Disassembly Process and Model of Waste Mobile Phone Circuit Board Components

Dismantling the waste printed circuit boards (WPCBs) of obsolete mobile phones is essential for resource recycling and environmental protection. An automated WPCB disassembly equipment based on the hot-vibration process was designed and applied, with optimized process conditions of a heating temperature of 250 °C and an equipment amplitude of >3.66 mm. The dismantling rate for electronic components and metal shields was 98%, but disassembly of components with underfill was less effective. Both simulation and actual measurement results of the equipment’s thermal field showed that the temperature inside the disassembly bin was uniform, with a maximum temperature difference of 6–8 °C. The area of the low-temperature region accounted for approximately 5% of the total area. The acceleration ranged from 2.11 to 8.28 g when using the disassembly force model. This equipment and process can be applied to disassemble large quantities of WPCBs.

Towards the definition of WEEE recycling targets in Ecuador. A case of study for mobile phones.

The rise of consumption patterns of electrical and electronic equipment (EEE) and the generation of waste EEE (WEEE) has been strongly increasing globally. Recycling rates (RRs) are one of the main indicators for monitoring the progress towards a circular economy and establishing recovery and treatment schemes. For this reason, this study discusses the setting of recycling targets for WEEE in Ecuador, using mobile phones as a case study. Firstly, the generation of mobile phone waste from 2012 to 2018 is estimated based on literature review. The most appropriate model for estimating WEEE generation is selected according to the applicable market conditions, input requirements and available data. Then, the composition of a mobile phone is determined through an extensive literature review. Based on these results, the materials' environmental impact and potential economic value are approximated using the ReCiPe Endpoint (H, A) method and the prices of virgin materials, respectively. The estimation shows that in Ecuador an average of 2 million devices are discarded every year, which represents an interesting source of resources but currently does not have appropriate management. Ecuador has implemented regulatory frameworks in favour of the integral management of these wastes. However, mass-based collection targets still appear to be the only available measure. Therefore, national results on electronics recycling do not allow adequate monitoring of progress towards a circular economy and largely neglect environmental aspects and economic potential.

Synthesis of AgNPs from waste mobile phone circuit boards using an emulsion liquid membrane method

The disposal of mobile phone print circuit boards (WMPCBs) has now been a problem because of the continually increasing production of mobile phones. It could be considered a new source of precious metal but may jeopardize the environment and human health without proper management. An emulsion liquid membrane (ELM) method is applied and improved to recover silver from WMPCBs and prepare AgNPs. The effects of significant operating parameters were studied for a better understanding of the ELM process. Under the optimized conditions i.e., 0.25 % (v/v) Cyanex 302, 6 % (v/v) Span 80, 5 % (w/v) ASC, 3500 rpm emulsification speed, 10 min emulsification time, 300 rpm extraction stirring speed, 10 min extraction stirring time and 3 (v/v) phase ratio, 98.7 % silver was extracted. AgNPs produced were flower structures assembled by a group of individual nanosheets with a diameter of 800–1400 nm and a thickness of 10–14 nm. The purity was 98.7 % and the yield was 96.6 %. AgNPs of oblate spheroidal structure with a diameter of 30–50 nm could be synthesized by controlling the concentration of Span 80 in ELM. The current study intends to fulfill the gap by exploring the recovery of silver from WMPCBs by the ELM method.

Forecasting Waste Mobile Phone (WMP) Quantity and Evaluating the Potential Contribution to the Circular Economy: A Case Study of Turkey

Information and communication technology (ICT)-based products have a significant effect on increasing levels of waste electrical and electronic equipment (WEEE) or electronic waste (e-waste) due to their shorter lifespan as a result of rapid technological changes. Mobile phones are the most popular ICT products, and their market share is increasing gradually. Therefore, effective management of waste mobile phones (WMP) is sought as their recovery brings enormous economic and regulatory benefits. Forecasting the quantities of WMP and their recoverable material content generates valuable data for the related stakeholders in the circular economy (CE) in the design and management of their supply chain networks. This paper presents an approach to determining the WMP quantity for Turkey considering the system from sales to end-of-life (EOL) stages and the years between 2001 and 2035. The proposed model includes two main parts: estimation and forecasting. Firstly, the generated WMP quantity is estimated based on dynamic lifespan and sales using the Distribution Delay (DD) Method considering the years from 2001 to 2020. To select the most suitable model for future projection, seven different time series methods (e.g., Simple Exponential Smoothing, Holt’s, Logistics, Gompertz, Logarithmic, Bass, and ARIMA models) are considered to estimate the generated WMP. For the given data, the Holt’s Method is determined to be the best method to forecast the WMP quantities for the years from 2021 to 2035. In addition, waste materials amount and revenue potentials are estimated for the years from 2001 to 2035. The WMP for Turkey is expected to be approximately 11.5 million units and has a 52 million US$ revenue potential in 2035. The present study contributes to the literature, as it is the first holistic forecasting study on the quantification of WMPs in Turkey. Moreover, since WMPs include remarkable recovery potential in terms of CE, the data and findings of this study may help policymakers, governments, producers, consumers, and all stakeholders to establish effective e-waste management approaches.

High-efficient removal of tetrabromobisphenol A from waste mobile phone printed circuit boards leached solution by micellar enhanced ultrafiltration

Background: Tetrabrombisphenol A (TBBPA) is one of the major brominated flame retardants (BFRs) used in waste mobile phone printed circuit boards (WMPPCB) that accounts for approximately 60% of the total BFR market. Methods: The potential of TBBPA removal from WMPPCB leached solution was investigated using micelle-enhanced ultrafiltration (MEUF) in the presence of cationic, anionic, and nonionic surfactants. The efficiency of several parameters including surfactant concentration, transmembrane pressure (TMP), pH, and TBBPA concentration, was evaluated to improve the MEUF. The optimal conditions were used to assess the MEUF for removing TBBPA in a real sample. Results: The cationic surfactant cetylpyridinium chloride (CPC) showed better performance than other surfactants in removing TBBPA due to its electrostatic interactions with anionic forms of TBBPA. The removal efficiency of TBBPA increased from 48.99% to 99.10% by adding a surfactant (less than the critical micelle concentration). Increasing the pH in the range of 5 to 11 increased the efficiency of TBBPA removal due to the increase in the TBBPA solubility in the micelles. TMP had the most significant effect on permeate flux compared to other parameters but did not significantly affect the TBBPA removal efficiency. The MEUF process effectively removed (above 99%) TBBPA in the concentration range of 20 to 80 mg L-1 under optimal conditions. The HPLC-UV analysis of the real sample indicated the removal efficiency of 100% of TBBPA. Conclusion: MEUF using CPC is a critical performance technology for removing TBBPA from the leached solution of electronic waste.

Study on the Influencing Factors of "Internet +" Recycling of Waste Mobile Phone Dominated by Retailers

Study on the Influencing Factors of "Internet +" Recycling of Waste Mobile Phone Dominated by Retailers

Differences and determinants for polluted area, urban and rural residents’ willingness to hand over and pay for waste mobile phone recycling: Evidence from China

Currently, China has the largest generation volume of waste mobile phones (WMPs), but the recycling rate is still negligible. How to improve the willingness to hand (WTH) over to formal recycling channels and willingness to pay (WTP) have become the most core problems in the e-waste recycling industry. As the important link between WMPs generation and collection, the residents’ role and function are attracting more and more attention. Thus, this study is designed to identify the determinants of the residents’ WTH and WTP for WMPs through the contingent valuation method (CVM). At the same time, it will explore the current existing gaps from the urban and rural residents. Especially, this study also considers Guiyu Town as one special rural region for understanding the differences with other regions. The results show that the respondents generally have the relatively lower knowledge and cognition on WMPs recycling. Only 9.4% respondents are satisfied with the current government's management of WMPs. Personal information leakage is an important reason for low WTH. The WTH of Guiyu, urban and rural respondents were 51.3%, 45.9% and 41.2%, respectively; while their WTP were 46.80%, 31.70% and 37.80%, respectively. Finally, it is estimated that their WTP values were 18.75 ($2.81), 16.14 ($2.42) and 15.85 ($2.38) RMB per unit, respectively. The demographic variables, cognition and attitude are important factors on all residents' WTH and WTP. Meanwhile, it is indicated that if owning higher WTH, the residents will trend to higher WTP. Especially, the WTH and WTP of Guiyu residents are higher than other residents.

Estimating the Generation of Discarded Mobile Phones and Highlighting Areas for Recycling Precious Metals from Printed Circuit Boards in Thailand

Over the last decade, Thailand imported approximately 21 million units of new mobile phones every year, equivalent to 262 million. While technology changes, consumers want the newest model to serve their lifestyle. These discarded mobile phones will be a challenging issue for waste management systems because of the metals in mobile phones, especially in printed circuit boards (PCBs). Sufficient and sustainable management is needed to maximize the benefits of recycling metals and minimize potential risks to public health. This study aims to estimate the possible range of DMP generation in Thailand (2012–2021) with the Approximation 2, Simple Delay, and Time Step methods using the government published data and a literature review. The results show that the discarded mobile phones ranged from approximately 1700 to 2500 tons/year, equivalent to 0.027 to 0.038 kg/year/capita over the last ten years. In 2021, more than half of the total mobile phone waste generated in the northeastern and central areas of Thailand was around 468.73 and 325.14 tons/year, respectively. Additionally, 1.28 tons of precious metals (Ag, Au), 5.33 tons of rare earth elements, and 7.26 tons of toxic metals (As, Cd, Cr, Pb) can be found in the PCB waste of DMPs.

Remediation of metals and plastic from e-waste by iron mine indigenous acidophilic bacteria.

The growing consumption of electrical and electronic equipment leads to high amounts of electronic waste (e-waste), which is now considered the fastest-growing waste stream at the national and international levels. As well as being a potential secondary resource due to its precious metals content, e-waste also contains strategic metals and plastics. For instance, mobile phones have about 25-55% plastic substances. A few studies have been performed to investigate the potential of indigenous bacteria in metals' bioleaching from the polluted environment. Heterotrophic bioleaching potential in acidic conditions had been preliminarily investigated. Two soil types of iron ore were considered the source of indigenous bacteria. Despite the acidophilic nature of the bacterial consortium, they continued their leaching activity regardless of alkaline conditions. Maximum biorecovery rate related to copper (4%) responding to the main soil, owing to the higher copper content of mobile phone waste. Chromium had the least recovery rate (⩽0.002%). Overall, the maximum metal recovery rate was 4.7%, achieved by tailing heterotrophs at an e-waste loading of 10 g l-1. Statistical analysis had shown that there was no significant difference between the metal recovery rates and soil type or even the solid-liquid ratio (p > 0.05). Although acidophilic indigenous heterotrophs could not be an appropriate alternative for a large amount of metal recovery process, they might have considerable potential in the bioremediation of e-waste plastic fractions and metals in low concentrations simultaneously.