Palladium Recovery through Membrane Capacitive Deionization from Metal Plating Wastewater

Abstract

The potential application of membrane capacitive deionization (MCDI) for recovery of palladium (Pd) ions from catalyst solution wastewater generated from plating industry was investigated in this study. Several major issues were explored in this work to verify the suitability of MCDI for Pd recovery from a practical perspective: adsorption and desorption efficiencies, desorption mechanisms into high concentration of Pd concentrate, and its sustainability in long-term operation. The lab-scale MCDI operation achieved satisfactory and highly competitive Pd removal (99.07-99.94% removal with 1.42-1.52 of Pd selectivity over ammonium ions) showing that Pd can be effectively collected from plating industry wastewater. High concentration of Pd concentrate (64.77 and 919.44 mg/L of Pd from the 10 and 100 mg/L Pd containing catalyst solution, respectively) was obtained through successive five operation cycles of adsorption/desorption phases. However, it is significant to note that the desorption efficiency was inversely proportional to the concentration of Pd concentrate which is likely due to the Pd ions discharged from carbon electrode toward Pd solution against the enhanced concentration gradient. The long-term operation results suggest that scaling could reduce the MCDI efficiency during Pd recovery (0.17% decrease in Pd removal for every cycle on average) and hence may require adequate electrode cleaning regime.

Effect of Brine Water on Discharge of Cations in Membrane Capacitive Deionization and Its Implications on Nitrogen Recovery from Wastewater

“…To sum up, the ionic strength gradient between the surface of the carbon electrode and the aqueous brine solution affects the ion discharge kinetics. The slowed desorption kinetics are consistent with the findings from earlier studies which probed the effect of brine composition on ion discharge in (M)CDI[30,34].There are lot of things to understand the real mechanisms involved in the desorption of adsorbed ions from the electrodes. The desorption efficiencies could also be different for each ionic species and also for different electrodes and IX membranes.…”

“…The MCDI experiments were carried out in a lab-scale flow-through system as described in our previous work [29,30]. The dimensions of the rectangular feed channel of the test cell were 10 cm W x 10 cm L, and thus the effective electrosorption area was determined to be 100 cm 2 .…”

Electrochemical approaches for selective recovery of critical elements in hydrometallurgical processes of complex feedstocks

“…Palladium was recovered by MCDI by using commercial cation and anion exchange membranes . Selectivity of Pd over ammonium ions was of 1.42–1.52, while removal efficiency was 99.07–99.94% ( Kim et al., 2017a ).…”

Phosphorus removal mechanisms from domestic wastewater by membrane capacitive deionization and system optimization for enhanced phosphate removal

“…Capacitive deionization (CDI), on the other hand, is a promising technology that uses electrophoretic driving forces to remove charged ions from an aqueous solution (Pekala et al, 1998). It was shown to have great application potential for seawater and brackish water desalinations (Biesheuvel et al, 2017;Dorji et al, 2018), water softening (Tuan et al, 2015), selective removal of specific ions (Choi et al, 2016), resources removal and recovery (Huang et al, 2017;Kim et al, 2018), and water reclamation (Anderson et al, 2010). CDI operates at a low voltage, generally less than 1.23 V, to avoid faradaic reactions that can result in water electrolysis (Liang et al, 2017;Shanbhag et al, 2017;Zhang et al, 2018).…”