Adsorptive, electrochemical and computational approaches for the recovery of precious metals from wastewater

Abstract

The global shortage of clean water and rising demand for precious metals have intensified interest in alternative resource streams beyond conventional mining. Wastewater, particularly from electronic manufacturing and electroplating processes, often contains metal concentrations that exceed those found in natural ores. This characteristic positions wastewater not only as a pollutant matrix but also as a valuable secondary resource. With increasing demand for both water availability and metal supply chains, attention has gradually shifted toward alternative recovery routes that can serve dual purposes. In this regard, the present review takes a closer look at the combined use of adsorption and electrochemical techniques, not as parallel options, but as interdependent steps within a single process. Individually, each method brings certain strengths, although neither is without limitations. Adsorption is widely recognized for its ability to selectively capture and concentrate metal ions, even in fairly complex aqueous environments. Once metals are taken up, their regeneration and recovery often requiring additional chemicals and, in some cases, generating secondary waste streams that are challenging to manage. Electrochemical approaches, by contrast, allow direct metal recovery through reduction processes and can regenerate the working surface under suitable conditions. However, these systems tend to lose effectiveness when selectivity becomes critical, particularly in multi-ion solutions where competing species interfere. In this perspective, adsorption is integrated with electrochemical treatment. The adsorption step effectively isolates and enriches the target species while the electrochemical step of electroreduction and recovery facilitates regeneration without extensive chemical input. Though it is not a perfect solution in every case, yet its advantages cannot be overlooked. The current review brings these aspects together by linking material characteristics with process performance, examining a range of adsorbent systems with emphasis on how structural features influence selectivity and reuse, alongside the emerging role of computational approaches in the design of adsorbents and the optimization of conditions to enhance the uptake and recovery of precious metals. Overall, the integration of adsorption and electrochemical methods minimizes reagent usage and facilitates cyclic operations for the recovery of precious metals from wastewater, which is increasingly significant for promoting circular resource utilization.