Polymeric Inclusion Membrane (PIM) for Thiocyanate Extraction from Acid-Neutral Solution

Thiocyanate can be found in the gold mine tailing that use cyanide method for gold extraction. Reaction of cyanide ion and sulphuric ion producing thiocyanate in the tailing which enhancing the environmental problem. A new polymeric inclusion membrane (PIM) has been developed to extract thiocyanate from acid to neutral solution. PIM was produced by diluting PVC as base polymer, trioctylamine (TOA) and tetraoctyl methyl ammonium chloride (TOMAC) as carriers, and 1-decanol as plasticizer in tetrahydrofurane (THF) as solvent. Thiocyanate concentration was measured based on the formation of Fe(III)-thiocyanate complex at 457 nm. As a result, thiocyanate could be extracted up to 42% using PIM technique with composition (w/w) 70% PVC, 15% TOMAC as carrier, and 15% 1-decanol as plasticizer. Feed phase was contained of 80 mg/L thiocyanate solution at pH 4. Stripping phase was contained of sodium chloride solution of 1.0 M.