Recovery of precious metals from processed wastewater: conventional techniques nexus advanced and pragmatic alternatives

Abstract

The loss of highly sought-after metals such as gold, silver, and platinum during extraction processes not only constitutes a significant waste of valuable resources but also contributes to alarming environmental pollution. The ever-growing adverse impacts of these highly valued metals significantly increase the contamination of water bodies on discharge, while reducing the reusability potential of their corresponding processed wastewater. It is, therefore, of great interest to identify pragmatic solutions for the recovery of precious materials from processed water. In this review, pollution from targeted precious metals such as gold, silver, platinum, palladium, iridium, ruthenium, and rhodium was reviewed and analyzed. Also, the hazardous effects are elicited, and detection techniques are enumerated. An insightful approach to more recent treatment techniques was also discussed. The study reveals nano- and bio-sorption techniques as adoptable pragmatic alternatives, among other techniques, especially for industrial applications with merits of cost, time, waste management, and eco-friendliness. The results indicate that gold (46.2%), palladium (23.1%), platinum (19.2%), and silver (11.5%) are of utmost interest when considering recent recovery techniques. High yield and cost analysis reduction are reasons for the observed preference of this recovery process when considering groups of precious metals. The challenges and prospects of nanomaterials are highlighted. HIGHLIGHTS Precious metals are present in processed wastewater as pollutants.; Conventional recovery methods are associated with limitations.; Bio- and nano-sorption provide pragmatic alternatives to other existing techniques with cost-effectiveness, simplicity of design, and eco-friendly disposal methods.; The technological approach via trapping and impregnation of precious metals in sorbents is effective in the recovery of precious metals.;

Keywords

• biosorption
• metal recovery
• nanomaterials
• precious metals
• sequestration