Selective Separation of Nickel (II) and Cobalt (II) from Waste Water by Using Continuous Cross-Flow Micellar Enhanced Ultrafiltration with Addition of Chelating Agent

Abstract

The performance of continuous cross-flow micellar enhanced ultrafiltration (MEUF) is evaluated for the selective separation of nickel (Ni²⁺) and cobalt (Co²⁺) from the aqueous stream using anionic surfactant sodiumdodecyl sulfate (SDS) and the mixture of the anionic and nonionic surfactant (SDS+TritonX-100) with the addition of iminodiacetic acid (IDA) as a chelating agent. Operating parameters like operating time (upto 100 min), cross flow rate (100–175 mL/min.), pH of the feed solution (3-6), molar concentration ratio of the chelating agent to metals (C/M ratio, 0.5–2.5), and molar concentration ratio of the surfactant to metals (S/M ratio, 5–9) were studied to investigate the effectiveness of the process on selective separation. For the single surfactant system at all empirically selected parameters, 92% Ni²⁺ in the permeate and 94% Co²⁺ in the retentate was achieved whereas for the mixed surfactant system 93% Ni²⁺ in permeate and 84% Co²⁺ in retentate was achieved. Flux variation for single and mixed surfactant system was studied. Flux observed for the single surfactant system was 36 L/m².h and for the mixed surfactant system was 31.5 L/m².h. Flux measurement also indicates insignificant fouling of the membrane.

Keywords:

• chelating agent
• Co²⁺
• MEUF
• Ni²⁺
• selective separation