Forecasting model to assess the potential of secondary lead production from lead acid battery scrap

The physicochemical interacting mechanisms and real-time spectral induced polarization monitoring of lead remediation by an aeolian soil

Compared to traditional lead-remediating materials, natural-occurring paleosol is ubiquitous and could be a promising alternative due to its rich content in calcite, a substance known for its lead-removal ability via carbonate dissolution-PbCO3 precipitation process. Yet, the capability of paleosol to remediate aqueous solutions polluted with heavy metals, lead included, has rarely been assessed. To fill this gap, a series of column permeation experiments with influent Pb2+ concentrations of 2000, 200, and 20 mg/L were conducted and monitored by the spectral induced polarization technique. Meanwhile, the SEM-EDS, XRD, XPS, FTIR and MIP tests were carried out to unveil the underlying remediation mechanisms. The Pb-retention capacity of paleosol was 1.03 mmol/g. The increasing abundance of Pb in the newly-formed crystals was confirmed to be PbCO3 by XRD, SEM-EDS and XPS. Concurrently, after Pb2+ permeation, the decreasing calcite content in paleosol sample from XRD test, and the appearance of Ca2+ in the effluent confirmed that the dissolution of CaCO3 followed by the precipitation of PbCO3 was the major mechanism. The accumulated Pb (i.e., the diminished Ca) in paleosol was inversely proportional (R2 >0.82) to the normalized chargeability (mn), an SIP parameter denoting the quantity of polarizable units (primarily calcite).

Forecasting of secondary lead recovery from motorcycle batteries in Brazil: a contribution to waste management

This study aims to predict the potential for secondary lead recovery from motorcycle batteries in Brazil, since this is considered the second largest category of automobiles in the country. To achieve this objective, a forecasting model based on the ARIMA methodology was applied, with input data taken from Brazilian sectorial platforms. Furthermore, an analysis of the data, of the residuals, autocorrelation tests, as well as Kolmogorov-Smirnov and Dickey-Fuller tests, were performed. The SARIMA model (3,1,0) (2,0,0)12 presented a better adaptation to the behavior of the series. The results showed that the amount of secondary lead obtained based on the forecast model will be 89,972,842.08 million tons between 2021 and 2030 (14 million tons of lead originated only from motorcycle LABs in 2021). These results show a possible insufficiency of the installed capacity to supply the amount of lead to be processed in the country, not to mention the LABs from other vehicles (light and heavy) and other emerging battery technologies from electric vehicles. In addition, an analysis was conducted on the importance of secondary lead for the economy and the dangers of illegal recycling in Brazil. In general, this study contributes to the understanding of the importance of secondary production of lead in Brazil, an important asset for a country that does not have sufficient primary production for its domestic demand. The findings may assist in several alternatives for the proper planning and management of the collection, disposal and recycling of lead, providing the Brazilian government with directions for the development of new policies related to lead recycling.

Estimation of lithium-ion battery scrap generation from electric vehicles in Brazil

Among the diversity of electronic waste, lithium-ion batteries (LIB), specifically those used in the propulsion of electric vehicles (EV), are considered pollutants of significant impact. When not used and disposed of correctly, LIBs can cause damage of various types to health and the environment. The electrochemical instability inherent in these batteries releases toxic gases, risks explosion, and is always associated with a series of electronic circuits composed of various metals, including heavy metals. As a result of public policies to encourage vehicle electrification, the Brazilian EVs sector has shown high growth, even within an economic crisis scenario. In this sense, this study presents a model for estimating the production of electric vehicles and the generation of scrap LIBs, based on time series, combining battery life, car sales data, and the mileage profile covered by a car in Brazil. Around 700 thousand EVs are expected to be circulating in Brazil by 2030, with approximately 500 thousand LIBs to be converted into scrap by 2040. Finally, the delaying effect of the scrap generated from LIBs is highlighted, in line with the battery life, which, in the future, may have a very negative impact on waste management.

Forecasting e-waste recovery scale driven by seasonal data characteristics: A decomposition-ensemble approach

Forecasting the scale of e-waste recycling is the basis for the government to formulate the development plan of circular economy and relevant subsidy policies and enterprises to evaluate resource recovery and optimise production capacity. In this article, the CH-X12 /STL-X framework for e-waste recycling scale prediction is proposed based on the idea of 'decomposition-integration', considering that the seasonal data characteristics of quarterly e-waste recycling scale data may lead to large forecasting errors and inconsistent forecasting results of a traditional single model. First, the seasonal data characteristics of the time series of e-waste recovery scale are identified based on Canova-Hansen (CH) test, and then the time series suitable for seasonal decomposition is extracted with X12 or seasonal-trend decomposition procedure based on loess (STL) model for seasonal components. Then, the Holt-Winters model was used to predict the seasonal component, and the support vector regression (SVR) model was used to predict the other components. Finally, the linear sum of the prediction results of each component is used to obtain the final prediction result. The empirical results show that the proposed CH-X12/STL-X forecasting framework can better meet the modelling requirements for time-series forecasting driven by different seasonal data characteristics and has better and more stable forecasting performance than traditional single models (Holt-Winters model, seasonal autoregressive integrated moving average model and SVR model).

A Green Lead Recycling Strategy from Used Lead Acid Batteries for Efficient Inverted Perovskite Solar Cells

Lead is widely used as a crucial elemental for lead acid batteries (LABs) and emerging halide perovskite solar cells (PSCs). However, the use of soluble lead will raise environmental concerns. For the purpose of Pb recycling, herein, we report a reactant-recycling strategy to extract Pb from used LABs and synthesize high-purity PbI₂. The recycled PbI₂ shows smaller grain size, higher crystallinity, and higher thermal stability compared to the commercial sources. Perovskite films deposited with the high-quality PbI₂ show larger grain size and fewer defects than the commercial ones. Consequently, the synthesized PbI₂ enables a power conversation efficiency of 20.45% for the inverted MAPbI₃ (MA= methylammonium) PSCs with excellent air stability. This work offers a novel strategy for lead recovery from LABs and a green path for the realization of high-performance PSCs with high defect tolerance.

Recycling Spent Lead-Acid Batteries into Lead Halide for Resource Purification and Multifunctional Perovskite Diodes

Lead-acid batteries are a reliable and cost-effective uninterrupted power supply for cars, wheelchairs, and others. Recycling the spent lead-acid batteries has increased cost and could be a serious pollution issue after extensive use. It is important to exploit new-generation application to increase their value. In this article, we used a simple method for recycling spent lead-acid batteries for a useful lead iodide resource with a high purity of over 99% and a recycling yield of 93.1% and then fabricated multifunctional FAPbI₃ perovskite diodes using recycled lead iodide (PbI₂). The cost of recycled PbI₂ based on lab-grade chemicals is estimated to be only 13.6% that of lab-grade PbI₂, which undoubtedly greatly reduces the preparation cost of devices in the lab. The external quantum efficiencies of our perovskite diodes prepared with commercial and recycled PbI₂ are 19.0 and 18.7%, respectively, which shows that the performance of the device prepared from recycled PbI₂ is comparable to that of commercial lab-grade PbI₂. Based on the expense of industrial-grade chemicals, the cost of recycled PbI₂ is extrapolated to be 70.2% that of industrial-grade PbI₂. Therefore, it can not only offer an approach to recycle hazardous solid waste but also save manufacturing cost of new-generation photoelectric devices, leading to earning additional value for lead waste.