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Crosslinker-less surface-imprinted Macadamia derived activated carbons for trace Cr(III) removal from aqueous solution

Lesaoana, Mahadi, Pakade, Vusumzi E., Chimuka, Luke
Environmental technology & innovation 2019 v.14 pp. 100336
Fourier transform infrared spectroscopy, Macadamia, acid mine drainage, activated carbon, adsorbents, adsorption, aqueous solutions, carboxylation, chromium, ecosystems, humans, leaching, pH
Leaching of chromium compounds into the environment from the electroplating process may cause health detrimental effects to humans and ecosystem exposed to these compounds. Ion-imprinted adsorbents possessing high selectivity are required to eradicate trace chromium compounds from complex matrices. A pseudo-surface imprinting technique was applied on carboxylated Macadamia activated carbon (MAC) by grafting MAC with triethylenetetramine, N,N’-diisopropylcarbodiimide and CrCl3⋅6H2O (template ion) to produce MAC-pseudo-ion imprinted adsorbents (MAC-PIIA). MAC-pseudo-non-imprinted adsorbent (MAC-PNIA) counterparts were prepared by the same procedure, but Cr3+ was excluded in the synthesis. The presence of N–H and C–N bands in FTIR spectra at 3005 and 1232 cm−1, respectively, confirmed successful grafting. The adsorption performance of the MAC-PIIA recorded at pH 5, 120 min, and 3.3 g/L dosage concentration, was 80% (69.61 mg/g). Application of the MAC-PIIA (72.2%) and MAC-PNIA (56.0%) on spiked acid mine drainage artificial sample led to collapse in the removal efficiency. Multilayer Freundlich adsorption described the mechanism.