Current trends in direct transformation of waste printed circuit boards (WPCBs) into value-added materials and products

Circular economy and electronic waste (e-waste) are among today's hot topics for scientists, environmentalists, and even policymakers. A considerable fraction of e-waste is waste printed circuit boards (WPCBs), which contains a wide range of metals, ceramics, and polymers. This variety of substances has made the recycling of WPCB an interesting challenge. Recently, there have been trends to not only recover WPCB into raw materials but also add extra value to final products by transforming the products into nanomaterials, catalysts, composites, etc. In this article, first, a practical model for adding value through recycling processes is defined, that is, the valorization model. Second, the recent studies that offered functional commodities extracted from WPCB, with an average value higher than traditional recycling methods, are reviewed and compared, to conclude a future projection for WPCB valorization.