Electrochemical recovery of silver from waste aqueous Ag(I)/Ag(II) redox mediator solution used in mediated electro oxidation process

Abstract

The paper presents a process for the electrochemical recovery of silver(Ag) by electro deposition on the electrode surface from the waste solutions of Ag(I)/Ag(II) redox system in nitric acid medium used for the mediated electrochemical process. Electrochemical recovery was carried out in an undivided cell with DSA-O 2 electrodes at room temperature condition. At an optimized current density of 12 A/dm 2 , 99% of Ag recovery efficiency was achieved with high yield and low energy consumption. Experimental runs were made in order to observe the performance of the Ag recovery process. The operating conditions like current density, temperature and Ag(I) concentration of the electrolyte, the acid concentrations, agitation rate and inter-electrode distance were optimized.

WITHDRAWN: Fabrication of a novel hydrophilic ion-imprinted polymer based on silica-modified magnetic graphene oxide as a sensitive sorbent for the fast separation of silver ions from aqueous media

“…However, the accumulation of excess silver in environmental samples has highlighted the concern about its existence in the natural samples, which has led to the establishment of a threshold value of silver content in many countries to adjust a limited value for the silver ion existence in various samples [2]. By this, the issues of separation, enrichment, and determination of trace amounts of silver ions have received considerable critical attention [3] and had been studied by many researchers applying a variety of separation methods, including atomic flame absorption [4,5], solid phase extraction (SPE) [6], membrane filtration [7], chemical precipitation [8], ion exchange [9], electrochemical deposition [10] and adsorption [11,12].…”

“…Fig 10. The impact of temperature on the silver(I) adsorption onto Ag(I)-MGOIIP (initial concentration 10-300 mg L -1 , solution pH = 4, and adsorbent dosage = 1 g L -1 )…”

Effect of process parameters on the concentration, current efficiency and energy consumption of electro-generated silver(II)

“…NO x removal , organic waste destruction, e.g. phenol destruction (Matheswaran et al, 2007), isopropanol destruction (Sequeira et al, 2006), combined removal of methyl mercaptan and hydrogen sulfide (Muthuraman et al, 2011) and recovery of silver from aqueous waste (Raju et al, 2009); limited number of studies are focused on the electrochemistry of Ag(II) formation and its kinetics using expensive gold (Lehmani et al, 1996), platinum (Noyes & Kossiakoff, 1935) and boron-doped diamond anodes (Panizza et al, 2000). Though, other researchers ) have examined the cell performance of the Ag(II) generation in different acidic media using platinized titanium, the effect of operating parameters on the Ag(II) yield have been highly overlooked.…”

Mixed metal oxide anodes for electrochemical oxidation of phenolic pollutants

“…In most cases, the organic pollutants can be eliminated at the suitable chloride concentration (Martinez-Huitle and Ferro 2006). However, the variation of active chlorine species is strongly influenced by electrolysis conditions such as time, temperature and electrode material (Neodo et al 2012 (Chen et al 2012b, Chu et al 2012, Farmer et al 1992, Raju et al 2010. However, employing metallic mediators may have a risk of introducing high toxicity in the effluent and an addition step to recover the metallic species is required before discharging the effluents (Martinez-Huitle and Ferro 2006).…”