Cd²⁺ and Zn²⁺ Complexes with 2,4,6‐Tri(2‐pyridyl)‐s‐Triazine and Terephthalate for Rapid, High‐Capacity Adsorption of Congo Red

Abstract

Three crystal complexes were designed and synthesised through the solvothermal method, with Cu 2+ , Zn 2+ , and Cd 2+ ions as the metal centres and 2,4,6‐tri(2‐pyridyl)‐ s ‐triazine (TPTZ) and terephthalate (BDC 2− ) as the ligands. Their compositions were determined to be Cd(TPTZ)Cl 2 (Cd‐MOF), {[Zn(TPTZ)(BDC)] ⋅ 3H 2 O} n (Zn‐MOF), and Cu 2 (PCA) 2 (BDC)(H 2 O) 2 (Cu‐MOF) (PCA − =2‐pyridinium amide), respectively. Cd‐MOF can adsorb 90 % of Congo red (CR) in 10 s at room temperature and atmospheric pressure, and CR removal was complete at 20 s over a wide pH range. The adsorption capacity for CR reached 1440 mg g −1 in 5 min. Selective adsorption was demonstrated in mixed dyes. The adsorption kinetic data agree well with the pseudo‐second‐order kinetic model. The Temkin model was successfully used to evaluate the adsorption isotherms of CR on Cd‐MOF at room temperature, suggesting that adsorption occurs through a hybrid of monolayer and multilayer mechanisms.

Bimetallic PCN-333 with Modulated Crystallization and a Porosity Structure for a Highly Efficient Removal of Congo Red

“…11 Among these methods, adsorption stands out due to its straightforward operation, high efficiency, and absence of secondary pollution. 12 Traditional dye adsorbents include activated carbon, 13 cellulose, 14 zeolite, 15 chitosan, 16 graphene oxide, 17 and so on. However, their adsorption capacity for numerous dyes is relatively low.…”

“…Currently, prominent techniques for treating dye-contaminated wastewater encompass chemical precipitation, oxidation, photocatalytic degradation, coagulation/flocculation, membrane separation, reverse osmosis, and adsorption . Among these methods, adsorption stands out due to its straightforward operation, high efficiency, and absence of secondary pollution . Traditional dye adsorbents include activated carbon, cellulose, zeolite, chitosan, graphene oxide, and so on.…”