TY - JOUR
T1 - Ion exchange homogeneous surface diffusion modelling by binary site resin for the removal of nickel ions from wastewater in fixed beds
AU - Ma, Anthony
AU - Abushaikha, Ahmad
AU - Allen, Stephen J.
AU - McKay, Gordon
N1 - Publisher Copyright:
© 2018
PY - 2019/2/15
Y1 - 2019/2/15
N2 - The presence of toxic heavy metals in wastewater is a continuing threat to both the environment and living organisms. The present study investigates the ion-exchange potential of a dual-exchanged (Na+/H+) chelating resin to remove nickel ions from wastewater in a fixed bed column ion exchanger. The resin contains iminodiacetic acid (IDA) functional groups that can lead to the capture of heavy metal ions, provided that the pH condition and ratio of Na+: H+ are appropriate. Too much Na+ results in precipitation of nickel hydroxide, resulting in clogging of the ion exchange columns, while too much H+ in the solution leads to competitive protonation, reducing the uptake of Ni2+ ions. The experimental work has been supported by modelling results using a new film-homogeneous surface diffusion model (HSDM) to simulate the fixed bed breakthrough curves for the two exchange processes – assigned 1 and 2. The best fit model simulation curves were obtained by optimizing the overall external diffusion mass transfer coefficient kf (=5.41 × 10−3 cms−1), the surface diffusivity Ds (Ds1 = 224 × 10−7cm2s−1 for 2Na+/Ni2+ exchange; and, Ds2 = 3.60 × 10−10 cm2s−1 for 2H+/Ni2+ exchange) and the equilibrium constant KRP (KRP1 = 351 dm3/g for 2Na+/Ni2+ exchange; and KRP2 = 781 dm3/g for 2H+/Ni2+ exchange) until a good fit was obtained between the model and experimental data. Optimisation was achieved by employing the downhill simplex method and performing a multidimensional minimization of the objective function, i.e. minimizing the SSE between the experimental data and the model prediction.
AB - The presence of toxic heavy metals in wastewater is a continuing threat to both the environment and living organisms. The present study investigates the ion-exchange potential of a dual-exchanged (Na+/H+) chelating resin to remove nickel ions from wastewater in a fixed bed column ion exchanger. The resin contains iminodiacetic acid (IDA) functional groups that can lead to the capture of heavy metal ions, provided that the pH condition and ratio of Na+: H+ are appropriate. Too much Na+ results in precipitation of nickel hydroxide, resulting in clogging of the ion exchange columns, while too much H+ in the solution leads to competitive protonation, reducing the uptake of Ni2+ ions. The experimental work has been supported by modelling results using a new film-homogeneous surface diffusion model (HSDM) to simulate the fixed bed breakthrough curves for the two exchange processes – assigned 1 and 2. The best fit model simulation curves were obtained by optimizing the overall external diffusion mass transfer coefficient kf (=5.41 × 10−3 cms−1), the surface diffusivity Ds (Ds1 = 224 × 10−7cm2s−1 for 2Na+/Ni2+ exchange; and, Ds2 = 3.60 × 10−10 cm2s−1 for 2H+/Ni2+ exchange) and the equilibrium constant KRP (KRP1 = 351 dm3/g for 2Na+/Ni2+ exchange; and KRP2 = 781 dm3/g for 2H+/Ni2+ exchange) until a good fit was obtained between the model and experimental data. Optimisation was achieved by employing the downhill simplex method and performing a multidimensional minimization of the objective function, i.e. minimizing the SSE between the experimental data and the model prediction.
KW - Binary-site surface diffusion modelling
KW - Breakthrough curves
KW - Fixed bed ion exchange
KW - Iminodiacetate resin
KW - Nickel ions removal
UR - http://www.scopus.com/inward/record.url?scp=85054053804&partnerID=8YFLogxK
U2 - 10.1016/j.cej.2018.09.135
DO - 10.1016/j.cej.2018.09.135
M3 - Article
AN - SCOPUS:85054053804
SN - 1385-8947
VL - 358
SP - 1
EP - 10
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
ER -