Functionalised Adsorbents for Removal and Recovery of Precious Metals and Chromium from Aqueous Solutions

Precious metals (PMs) such as palladium (Pd), platinum (Pt), and gold (Au) are economically valuable elements that commonly co-exist with toxic chromium(VI) [Cr(VI)] in industrial effluents. However, effective techniques for recovering or removing them from these wastewater streams remain a technological and critical environmental challenge. There is a limited comparative evaluation of various studies on functionalised adsorbents that have proven capability for wastewater treatment. Systematic and consolidated evaluation of functionalised adsorbents for the recovery or removal of PMs and Cr(VI) is offered in this review. Current developments in production and functionalisation approaches, characterisation techniques, adsorption studies (models, equilibrium, mechanisms), recovery and recycling methods are distinctly integrated. The reasonable framework informing the realistic layout and optimisation of future adsorbents by carefully investigating performance trends and identifying predominant gaps is demonstrated in the review. The perceptions reported are meant to support the enhancement of sustainable, effective, and scalable techniques applicable to wastewater remediation in mining, industrial, and emergingeconomy settings.