Highly porous activated carbons were fabricated from sunflower
seed hull by ZnCl2 activation and used as adsorbents to remove
Cr(VI) ions from aqueous solution. The activated carbons can be
dominantly microporous or mesoporous depending on the ZnCl2/
SSH impregnation ratios and activation temperatures. The
adsorption experiments indicated that the micropore dominant
samples were more favorable for Cr(VI) removal, and the existence
of some mesopore could facilitate the intra-particle diffusion,
hence enhance the Cr(VI) removal. The optimum pH for Cr(VI)
adsorption varied with the change of initial Cr(VI) concentration in
the solutions. In general, more acidic environment was required to
promote Cr(VI) adsorption in solutions with higher initial Cr(VI)
concentrations. However, acidic solution (pH 2.0 in this study)
would result in reduction of Cr(VI) to Cr(III), and consequently
reduce the overall removal efficiency of chromium element. The Cr
(VI) adsorption on SSH activated carbons can be well explained by
the Langmuir isotherm model and the pseudo-second-order
kinetic model, i.e., the adsorption occurred through monolayer
formation on the surface of adsorbents via chemical interactions
such as ionic or covalent bonds. Generally considering the low cost
and abundant raw material, easy fabrication process, high carbon
yield and high adsorption capacity, SSH-derived activated carbons
can be potentially used as attractive low-cost adsorbent for largescale
treatment of Cr(VI) containing industrial wastewaters
Highly porous activated carbons were fabricated from sunflowerseed hull by ZnCl2 activation and used as adsorbents to removeCr(VI) ions from aqueous solution. The activated carbons can bedominantly microporous or mesoporous depending on the ZnCl2/SSH impregnation ratios and activation temperatures. Theadsorption experiments indicated that the micropore dominantsamples were more favorable for Cr(VI) removal, and the existenceof some mesopore could facilitate the intra-particle diffusion,hence enhance the Cr(VI) removal. The optimum pH for Cr(VI)adsorption varied with the change of initial Cr(VI) concentration inthe solutions. In general, more acidic environment was required topromote Cr(VI) adsorption in solutions with higher initial Cr(VI)concentrations. However, acidic solution (pH 2.0 in this study)would result in reduction of Cr(VI) to Cr(III), and consequentlyreduce the overall removal efficiency of chromium element. The Cr(VI) adsorption on SSH activated carbons can be well explained bythe Langmuir isotherm model and the pseudo-second-orderkinetic model, i.e., the adsorption occurred through monolayerformation on the surface of adsorbents via chemical interactionssuch as ionic or covalent bonds. Generally considering the low costand abundant raw material, easy fabrication process, high carbonyield and high adsorption capacity, SSH-derived activated carbonscan be potentially used as attractive low-cost adsorbent for largescaleการรักษาประกอบด้วยอุตสาหกรรม wastewaters Cr(VI)
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