Recycling e-waste has been a significant topic for environmental protection and also for resource recovery. Waste tantalum capacitors (WTCs), widely existing in discarded small appliances, are rich in high quality tantalum (Ta) resources. However, recovering Ta from WTCs is difficult due to the tightly covered mold resin. This study proposes an efficient and environmentally friendly process using supercritical water (SCW) to decompose the organics and recover Ta from WTCs. Two methods of SCW were studied: SCW depolymerization (SCWD) and SCW oxidation (SCWO). The results indicated that the mold resin (packing) of WTCs were effectively decomposed by SCW treatments. The organic decomposition efficiency in SCWD was lower than that in SCWO. The optimal parameters for SCWD and SCWO were, respectively, considered to be 425 °C, 25 MPa, and 120 min and 400 °C, 25 MPa, and 90 min, adding a 10% volume ratio of H 2 O 2 . After SCWO treatment, Ta electrodes were directly recovered, and the purity of Ta could reach 93.18%. For the sample treated by SCWD, Ta powder could be further recovered by mechanical separation. This study presents an efficient and environmentally friendly process to recover Ta from e-waste, which is significant for resource regeneration and environmental conservation.

Electrocatalytic water oxidation is a rate-determining step in the water splitting process, however, its efficiency is significantly hampered by the limitations of the cost-effective electrocatalysts. Here, an advanced ultralow iridium...

No abstract

No abstract

Oxygen evolution reaction (OER) is regarded as the rate determining step of electrocatalytic overall water splitting, enabling the OER electrocatalysts should meet the standards of high activity, low cost, good...