Performance of an acid stable nanofiltration membrane for nickel removal from aqueous solutions: effects of concentration, solution pH and ionic strength

The performance of a nanofiltration membrane for the removal of the nickel ion was studied as a function of the nickel concentration, solution pH, and the background ionic strength of the solution. Nanofiltration is investigated as a means to determine to what extent the nickel ions could be removed from acid mine drainage; thus the effect of solution chemistry on nanofiltration performance is investigated. Higher fluxes (47.61/m(2)/h) were experienced at the lower nickel concentration (10mg/l) than at the higher (28.91/m(2)/h) nickel concentration (100mg/l). Higher nickel ion rejections (97.3%) were obtained at the higher nickel concentration (100mg/l) than at the lower nickel concentration (93.6%). Higher flux was obtained at the higher pH (pH 4) with a 0.01M NaCl background solution than at lower pH (pH 3) when a 0.05M NaCl was used as background solution. Higher nickel ion rejections were obtained at higher pH (pH 4) for the two ionic strength background solutions. Higher fluxes were also obtained with the lower NaCl background solution. Slightly higher ion rejections were obtained with the lower NaCl background concentration. It therefore appears that this nanofiltration membrane should be successfully applied for the removal of nickel ions from acid mine drainage.