Flexible thiourea-based covalent organic frameworks for ultrahigh mercury removal from aqueous solutions

被引：35

作者：

Hussain, Muzammil ^{[1
]}

Maile, Nagesh ^{[1
]}

Tahir, Khurram ^{[1
]}

Ghani, Ahsan Adul ^{[1
]}

Kim, Bolam ^{[1
]}

Jang, Jiseon ^{[2
]}

Lee, Dae Sung ^{[1
]}

机构：

[1] Kyungpook Natl Univ, Dept Environm Engn, 80 Daehak Ro, Daegu 41566, South Korea

[2] Korea Radioact Waste Agcy, R&D Inst Radioact Wastes, 174 Gajeong Ro, Daejeon 34129, South Korea

来源：

CHEMICAL ENGINEERING JOURNAL | 2022年 / 446卷

基金：

新加坡国家研究基金会;

关键词：

Covalent organic framework; Thiourea; Tautomerism; Mercury adsorption; SELECTIVE REMOVAL; ADSORPTION; EFFICIENT; HG(II); WATER; DESIGN; PB(II); CARBON; RESIN; IONS;

D O I：

10.1016/j.cej.2022.137410

中图分类号：

X [环境科学、安全科学];

学科分类号：

08 ; 0830 ;

摘要：

Covalent organic frameworks (COFs) have gained significant interest because of their exceptional performance in wastewater remediation. However, most COF adsorbents are synthesized using symmetrical rigid aromatic linkers, which limit the COF molecular design. Herein, we introduced a highly desirable thiourea moiety into a flexible crystalline framework through the condensation of the aliphatic thiocarbohydrazide linker with 1,3,5-triformylphloroglucinol knot. The synthesized flexible thiourea-based COFs, TpTch-90 and TpTch-120, existed in both keto and enol tautomeric forms simultaneously. Adsorption mechanism studies demonstrated that mercury adsorption favored keto and thiol tautomeric forms over their respective enol and thione tautomeric forms. TpTch-120 showed higher adsorption kinetics as it exhibited a high keto form as compared with that of TpTch90. However, both TpTch-90 and TpTch-120 COFs possessed very high Hg2+ adsorption capacity (4270 and 4277 mg/g) owing to abundant available chelating sites and their adsorption isotherms were fitted well by the Langmuir model. Both COFs were stable under harsh conditions and showed high removal efficiencies (> 97%) under strongly acidic conditions (1-3 M HCl). Moreover, TpTch-90 and TpTch-120 adsorbed Hg2+ selectively in the existence of competing metal ions attributable to the presence of soft-soft interaction between sulfur in COFs and mercury ions.

引用

页数：9