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Waste printed circuit boards (WPCBs) contain valuable material resources and hazardous substances, thereby posing a challenge for sustainable resource recovery and environmental protection initiatives. Overcoming this challenge will require mapping the toxic footprint of WPCBs to specific materials and substances used in manufacturing electronic components (ECs). Therefore, this work collected 50 EC specimens from WPCBs in five ubiquitous consumer products, such as television, refrigerator, air conditioner, washing machine and computer. The work extracted and analyzed metal contents and used leachability assessments based on tests adopted by the regulatory policies from China and the United States. The work found that copper and iron are the most abundant constituents in ECs, with concentrations ranging 5.90-796.62 g/kg and 0-831.53 g/kg, respectively; whereas abundance of precious metal content is in the order of silver > gold > palladium > platinum, with silver concentration ranging 15-5290 mg/kg. The content of marginally-regulated toxic substance arsenic ranged 0-9700 mg/kg; whereas fully regulated toxic metals such as chromium, lead and mercury did not exceed the thresholds set by China and US standards. The work found new toxic threats from arsenic and selenium leached from 20 of 50 ECs exceeding regulatory standards. These results will aid manufacturers and recyclers in protecting workers' health and environmental quality from arsenic and selenium pollution, and should initiate discussion about regulating these toxic components as part of a comprehensive program to reduce the toxic footprint of electronic products.

The concept of zero waste is an ideal situation that will require different solutions for different categories of waste. Electronic waste (E-waste), the fastest growing category of solid hazardous waste presents various unique challenges. Electronic product repair, reuse and remanufacture (3re) are crucial for effective source reduction of E-waste and the integration of the electronics industry into a circular or zero-waste economy framework. Increasingly, 3re implementation is restricted by regulatory difficulties, particularly the invocation of copyright laws. Here, we use the examples of electronic printer cartridges and restored compact discs (CDs) to identify the challenges and to explore solutions for managing the risks associated with E-waste through circular economy and the opportunities presented by innovative Blockchain solutions. A set of international consensuses on judicial definitions, such as 3re, refurbish fake/counterfeit product and copyright exhaustion, are proposed to accelerate source reduction in E-waste management toward the goal of zero waste. [Figure not available: see fulltext.]

Waste Electrical and Electronic Equipment (WEEE) contain toxic metals and organic compounds, posing significant threats to human health and environmental quality. The risks vary according to equipment types and components that are influenced by innovations in technical configuration and regulatory policy. To disentangle the relative impacts of these influences in protecting health and environment, we investigated 13 WEEE and 14 components using a life cycle impact assessment procedure. Additionally, we analyzed Waste Mobile Phones (WMPs) and Waste Printed Circuit Boards (WPCBs) from computers manufactured between 2002 and 2010 to identify trends of toxic chemicals and potential adverse impacts associated with technological configurations and regulatory policies. The results show that, among WEEE, Cathode Ray Tube TV presented the highest carcinogenicity and non-carcinogenicity toxicity potential. Waste Air Conditioner posed the highest potential for ecotoxicity. Among electronic components, Waste Organic Light Emitting Diode displays posed the highest potential risk for carcinogenesis, whereas WPCBs from laptop computers posed the highest potential risk for non-cancer diseases. Solid State Drives posed the highest risks for ecotoxicity. Chromium was associated with risk of carcinogenesis and non-cancer diseases; whereas Al and Fe posed the highest potential for ecotoxicological impacts. During the period covered by the study, innovations in technological configurations and regulatory policies demonstrably reduced the potential toxicity risks posed by E-waste, attributable to reduction in the concentrations of toxic organic chemicals in WMPs/WPCBs. These results advance current understanding of strategies to reduce the risks posed by WEEE through coordination of technological innovations and regulatory policies.

Phosphogypsum (PG) contains a lot of soluble phosphate (PO43--P) and fluorine ion (F-), which seriously has hindered the sustainable development of the phosphorous chemical industry. In this study, a new burning raw material (BRM) as an intermediate product in the cement production process was used for PO43--P and F- stabilize in PG. The stabilizing mechanism of PO43--P and F- were investigated by Fourier Transform infrared spectroscopy (FT-IR), X-ray diffractometer (XRD), Scanning Electron Microscopy (SEM), X-ray fluorescence (XRF) and X-ray spectroscopy system (XPS). The effect of PG and BRM weight ratio, solid-to-liquid ratio, reaction time, and reaction temperature on the concentrations of PO43--P and F- were studied. The results showed that the concentration of F- in the PG leaching solution was 8.65 mg/L and the stabilizing efficiency of PO43--P was 99.78%, as well as the pH of the PG leaching solution was 8.12 when the weight ratio of PG and BRM was 100:2, and the solid to liquid ratio was 4:1, reacting for 24 h at the temperature of 30 ℃. PO43--P and F- were mostly solidified as Ca5(PO4)3F, CaPO3(OH), Ca5(PO4)3(OH), Ca2P2O7·2H2O, CaSO4PO3(OH)·4H2O, CaF2, and CaFPO3·2H2O. Leaching test results indicated that the concentrations of PO43--P, F- and heavy metals were less than the integrated wastewater discharge standard (GB8978–1996). This study provides a new harmless treatment method for PG.