Manipulating Oxidation States of Copper within Cu-BTC Using Na₂S₂O₃ as a New Strategy for Enhanced Adsorption of Sulfide

Abstract

Manipulation of the oxidation states of the metal species within metal−organic frameworks leads to compositional, structural, and surface property evolutions, which will impact their performance as sorbents in adsorptive separation processes. In this study, we propose a new low-cost postsynthesis strategy to modify the oxidation states of copper species within the copper-1,3,5-benzenetricarboxylic acid (Cu-BTC) structure employing Na 2 S 2 O 3 as the reducing agent. The compositional and structural evolutions of the modified samples were thoroughly characterized by a series of methods, and the dimethyl disulfide (DMDS) adsorption performance was evaluated. Accurately controlled reduction of Cu(II) to Cu(I) and formation of nanopores in the modified Cu(I)/Cu(II)-BTC samples have been observed and confirmed experimentally. Specifically, the sample 0.46/Cu-BTC/24h with a Cu(I)/Cu(II) molar ratio of 1.79 exhibits both the highest DMDS adsorption capacity (146.66 mg-S/g) and fastest diffusion with D of 7.59 × 10 −13 cm 2 /s at 298 K. Further density functional theory calculations reveal that the modified Cu(I)/Cu(II)-BTC structures exhibit much higher interaction energy, E in , with DMDS (70.65 kJ/mol) than the parent Cu(II)-BTC (20.28 kJ/mol). Controllable reduction of Cu(II) to Cu(I) in Cu-BTC leads to significantly enhanced guest−host interactions as well as the formation of uniform nanoscale porosity leading to effect enhancement for the adsorption of DMDS using modified Cu-BTC materials.

Synthesis of nanocellulose aerogels and Cu-BTC/nanocellulose aerogel composites for adsorption of organic dyes and heavy metal ions

“…The available glycosidic bonds were hydrolyzed, and as a result, individual crystallites transversely were released. The dispersion of the produced CNC in water was promoted by the charged sulfate esters groups onto the surface, which were generated by the reaction between hydroxyl groups of MCC and sulfuric acid 28 . Although the resulting CNC could be turned into a gel by many physical methods, the next physical cross-linked aerogel would not have enough strength.…”

“…Cu-BTC was first reported in 1999 by Chui et al 26 and has attracted considerable attention both theoretically and experimentally 27 . Due to its open metal sites and large pore windows 28 , Cu-BTC has particular potential for adsorption and catalysis 29 , 30 . However, the powdered morphology of Cu-BTC, like other MOF compounds, restricts its applications 31 .…”

Synthesis of Nanocellulose Aerogels and Cu-BTC/Nanocellulose Aerogel Composites for Adsorption of Organic Dyes and Heavy Metal Ions

“…The available glycosidic bonds were hydrolyzed, and as a result, individual crystallites transversely were released. The dispersion of the produced CNC in water was promoted by the charged sulfate esters groups onto the surface, which were generated by the reaction between hydroxyl groups of MCC and sulfuric acid [25]. Although the resulting CNC could be turned into a gel by many physical methods, the next physical cross-linked aerogel would not have enough strength.…”

“…Cu-BTC was rst reported in 1999 by Chui et al [23] and has attracted considerable attention both theoretically and experimentally [24]. Due to its open metal sites and large pore windows [25], Cu-BTC has particular potential for adsorption and catalysis [26] [27]. However, the powdered morphology of Cu-BTC, like other MOF compounds, restricts its applications [28].…”

Structure–Property–Energetics Relationship of Organosulfide Capture Using Cu(I)/Cu(II)-BTC Edited by Valence Engineering

“…We systematically synthesized Cu-BTC and Cu(I)/Cu(II)-BTC sorbents using Na 2 S 2 O 3 as the reduction agent to manipulate the Cu(II)/Cu(I) ratio. 21 The synthesis procedure is described in the Supporting Information. Here, our samples are labeled x/Cu-BTC.…”