Copper-based ternary hydrotalcite as a catalyst for hydroxylation of phenolic compounds

TY - JOUR

T1 - Copper-based ternary hydrotalcite as a catalyst for hydroxylation of phenolic compounds

AU - Dai, Rongrong

AU - Liu, Baogui

AU - Zhang, Yan

AU - Pedersen, Jacob Nedergaard

AU - Zhang, Xiaowen

AU - Dong, Mingdong

AU - Guo, Zheng

PY - 2021/12

Y1 - 2021/12

N2 - Hydrotalcites with different cations were synthesized by co-precipitation method and characterized using different techniques. The catalytic activity of the hydrotalcites was studied using hydroxylation of phenol by H 2O 2 as a model reaction. The CuNiAl ternary hydrotalcite was found to be the best catalyst in this work; and the effects of reaction temperature, ratio of substrate:catalyst, H 2O 2 concentration, solvent and pH value of the medium were investigated. The results showed that under optimal reaction conditions, the conversion of phenol can reach up to 62.8%, with catechol and hydroquinone as the main products. The substrate scope was expanded to other phenol-derivatives, such as m-cresol and 3-ethylphenol. A plausible reaction mechanism was proposed based on the control reactions and XPS analysis. The CuNiAl hydrotalcite shows high toxicity (the 48 h LC 50 value of CuNiAl hydrotalcite was 2.12 mg/L) in the acute toxicity tests of Daphnia magna. However, after simple filtration of the solid catalyst, the 48 h LC 50 value of the remaining solution was increased to 83.46 mg/L. In all, the as-synthesized CuNiAl35 hydrotalcite offers a novel biodegradation pathway for in situ treatment of phenol-contaminated water or other phenolic pollutions when applied together with dioxygenases for further degradation of resulting catechols or hydroquinones.

AB - Hydrotalcites with different cations were synthesized by co-precipitation method and characterized using different techniques. The catalytic activity of the hydrotalcites was studied using hydroxylation of phenol by H 2O 2 as a model reaction. The CuNiAl ternary hydrotalcite was found to be the best catalyst in this work; and the effects of reaction temperature, ratio of substrate:catalyst, H 2O 2 concentration, solvent and pH value of the medium were investigated. The results showed that under optimal reaction conditions, the conversion of phenol can reach up to 62.8%, with catechol and hydroquinone as the main products. The substrate scope was expanded to other phenol-derivatives, such as m-cresol and 3-ethylphenol. A plausible reaction mechanism was proposed based on the control reactions and XPS analysis. The CuNiAl hydrotalcite shows high toxicity (the 48 h LC 50 value of CuNiAl hydrotalcite was 2.12 mg/L) in the acute toxicity tests of Daphnia magna. However, after simple filtration of the solid catalyst, the 48 h LC 50 value of the remaining solution was increased to 83.46 mg/L. In all, the as-synthesized CuNiAl35 hydrotalcite offers a novel biodegradation pathway for in situ treatment of phenol-contaminated water or other phenolic pollutions when applied together with dioxygenases for further degradation of resulting catechols or hydroquinones.

KW - Catechol

KW - Cu-containing hydrotalcites

KW - Daphnia magna

KW - Hydroxylation

KW - Phenol

KW - Toxicity

U2 - 10.1016/j.jece.2021.106390

DO - 10.1016/j.jece.2021.106390

M3 - Journal article

SN - 2213-3437

VL - 9

JO - Journal of Environmental Chemical Engineering

JF - Journal of Environmental Chemical Engineering

IS - 6

M1 - 106390

ER -