TY - JOUR
T1 - Dissolution, Adsorption, and Redox Reaction in Ternary Mixtures of Goethite, Aluminum Oxides, and Hydroquinone
AU - Zhang, Huichun
AU - Rasamani, Kowsalya Devi
AU - Zhong, Shifa
AU - Taujale, Saru
AU - Baratta, Laura R.
AU - Yang, Zijie
N1 - Publisher Copyright:
© Copyright 2019 American Chemical Society.
PY - 2019/2/21
Y1 - 2019/2/21
N2 - To better understand the oxidative reactivity of iron oxides in the fate of contaminants in acidic environments, we examined the reactivity of goethite in binary mixtures with Al 2 O 3 by carrying out oxidation experiments of hydroquinone (HQ) in the presence of goethite and/or Al 2 O 3 at pH 3. Kinetic results revealed inhibiting effects of 0.2-20 g/L of three different types of Al 2 O 3 on the oxidative reactivity of goethite. Surprisingly, soluble Al ions of 0.18-18 mM had a negligible impact on the reactivity. It turned out that the Fe 3+ dissolved from goethite partly contributed to the observed HQ oxidation and the Al 2 O 3 adsorbed the Fe 3+ to lead to the slower HQ oxidation. The observed pseudo-first-order rate constants in HQ oxidation had a strong linear correlation with Fe 3+ concentration in various goethite and Al 2 O 3 mixtures. Separate experiments confirmed the reactivity of Fe 3+ toward HQ and the linear correlation between [Fe 3+ ] and HQ oxidation reactivity. Finally, sedimentation experiments showed negligible heteroaggregation between goethite and AluC-Al 2 O 3 or nAl 2 O 3 but intensive heteroaggregation between goethite and Alu 65-Al 2 O 3 , which explained the observed highest inhibition effect of Alu 65. Overall, oxide mixtures are very complex whose reactivity is determined by many factors such as oxide dissolution.
AB - To better understand the oxidative reactivity of iron oxides in the fate of contaminants in acidic environments, we examined the reactivity of goethite in binary mixtures with Al 2 O 3 by carrying out oxidation experiments of hydroquinone (HQ) in the presence of goethite and/or Al 2 O 3 at pH 3. Kinetic results revealed inhibiting effects of 0.2-20 g/L of three different types of Al 2 O 3 on the oxidative reactivity of goethite. Surprisingly, soluble Al ions of 0.18-18 mM had a negligible impact on the reactivity. It turned out that the Fe 3+ dissolved from goethite partly contributed to the observed HQ oxidation and the Al 2 O 3 adsorbed the Fe 3+ to lead to the slower HQ oxidation. The observed pseudo-first-order rate constants in HQ oxidation had a strong linear correlation with Fe 3+ concentration in various goethite and Al 2 O 3 mixtures. Separate experiments confirmed the reactivity of Fe 3+ toward HQ and the linear correlation between [Fe 3+ ] and HQ oxidation reactivity. Finally, sedimentation experiments showed negligible heteroaggregation between goethite and AluC-Al 2 O 3 or nAl 2 O 3 but intensive heteroaggregation between goethite and Alu 65-Al 2 O 3 , which explained the observed highest inhibition effect of Alu 65. Overall, oxide mixtures are very complex whose reactivity is determined by many factors such as oxide dissolution.
UR - https://www.scopus.com/pages/publications/85062211539
U2 - 10.1021/acs.jpcc.8b12217
DO - 10.1021/acs.jpcc.8b12217
M3 - 文章
AN - SCOPUS:85062211539
SN - 1932-7447
VL - 123
SP - 4371
EP - 4379
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 7
ER -