Novel Triazine-Based Covalent Organic Framework as a Superadsorbent for the Removal of Mercury(II) from Aqueous Solutions

Abstract

The aim of this work was to develop a superadsorbent for the removal of Hg2+ ions from aqueous solutions. In this regard, a porous covalent triazine ring-based nanoneedle was synthesized through a facile hydrothermal method. The structure and morphology of the synthesized covalent triazine ring-based adsorbent were characterized by different techniques. The structural stability of the synthesized superadsorbent was examined under different temperatures and pH conditions. The maximum adsorption capacity of the prepared organic framework is 1826 mg g–1 for removing Hg2+ ions at ambient temperature and an optimum pH of 5. Different linear and nonlinear models were applied for the fitting of the obtained adsorption data. It was found that the adsorption data can be well fitted to the linear Langmuir model (R 2 = 0.998). The adsorption kinetics can also be well described by the linear pseudo-second-order model. To make a portable, highly sensitive, and low-cost device for in situ sensing of trace amounts of Hg2+ ions, the smartphone colorimeter platform was developed using accessible equipment. The response of the developed system for the determination of Hg2+ ions was linear in the concentration range of 0.25–15 mg L–1, and the detection limit of the system is 0.063 mg L–1 Hg2+. The total cost of the developed system is lower than 400 US dollars, and the cost of each analysis is lower than 0.05 US dollars. Ultrahigh adsorption capacity, chemical stability, and fast adsorption kinetics make the synthesized triazine-based covalent organic framework a suitable candidate for the removal of Hg2+ ions from industrial effluents.

Melamine-based functionalized graphene oxide and zirconium phosphate for high performance removal of mercury and lead ions from water

“…Compared to the other adsorbents, the MT-PRGO has higher overall performance compared to functionalized MOFs, GO, and mesoporous silica. 16,23,24,26,[35][36][37][38][39][40][41]…”

Orderly Porous Covalent Organic Frameworks-based Materials: Superior Adsorbents for Pollutants Removal from Aqueous Solutions

“…COF-based materials containing N, O, and S functional groups have higher adsorption capacity than single COFs due to electrostatic interaction, coordination, and chelation with metal ions. 48 , 49 , 51 , 53 , 71 In addition, the configuration transformation of functional groups (i.e., the structure would convert from the enol form to the ketone form) can improve the adsorption performance. 50 Combining the functional materials with COFs could enable an elegant combination of physical and chemical properties, synergistic effects, and multiple functions of individual components.…”

“…The key advantage of TFPPy-CHYD is that the secondary amine groups could combine with Hg 2+ reversibly. A novel stable triazine-based COF (T-COF) 53 could effectively adsorb Hg 2+ in the solution within 15 min with a saturated adsorption capacity of 1,826 mg·g −1 , which is attributed to the soft-soft interaction between N atoms in triazine and Hg 2+ .…”

“…These advantages, together with the characteristics of predesigned structure, ordered porous structure, and adjustable physicochemical properties, make COFs promising next-generation materials with remarkable high sorption capacities for radioactive/toxic metal ions and organic contaminants. 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 …”

A Perspective on the Application of Covalent Organic Frameworks for Detection and Water Treatment

“…Finally, Afshari et al [ 63 ] fabricated a triazine ring-based COF (T-COF) superadsorbent for Hg(II) removal. The group also developed a portable device for in situ detection of trace amounts of Hg(II).…”