CN-116536770-B - Cobalt (II) complex monocrystal and preparation method and application thereof

Abstract

The invention belongs to the field of removing pollutants in water by coordination chemistry and adsorption, and discloses a cobalt complex monocrystal and a preparation method and application thereof. The chemical formula of the compound is { [ Co 3 L(μ 2 -O)(DMF) 2 (H 2 O) 4 ]·(DMF) 3 } n , belonging to monoclinic system, the space group is C2/C, a= 29.732 (6) A, b= 17.665 (4) A, c= 31.723 (6) A, alpha=90°, beta=96.99 (3) °, gamma=90°, V=16538 (6) A 3 . Wherein L represents that 5,11,17, 23-tetra [ (m-carboxyphenyl) azo ] -25,26,27, 28-tetrahydroxycalix [4] arene loses four H atoms. The Co (II) complex monocrystal can rapidly adsorb and remove Pb 2+ 、Cd 2+ in water, realizes higher adsorption capacity, and shows high selectivity to Pb 2+ and Cd 2+ . The cobalt complex monocrystal can exist stably in water, and has good application prospect.

Inventors

• LIU LEILEI
• JIANG WEN
• YU CAIXIA
• ZHAO YUJIA

Assignees

• 烟台大学

Dates

Publication Date

20260512

Application Date

20230426

Claims (2)

1. 1. A cobalt complex monocrystal is characterized in that the chemical formula is { [ Co 3 L(μ 2 -O)(DMF) 2 (H 2 O) 4 ]·(DMF) 3 } n , n is a positive integer, belongs to monoclinic system, space group is C2/C, β=96.99(3)°,γ=90°, Wherein L represents 5,11,17, 23-tetra [ (m-carboxyphenyl) azo ] -25,26,27, 28-tetrahydroxycalix [4] arene loses four H atoms, and DMF represents N, N' -dimethylformamide.
2. 2. The use of the cobalt complex single crystal according to claim 1 for removing Pb 2+ and Cd 2+ from water.

Description

Cobalt (II) complex monocrystal and preparation method and application thereof Technical Field The invention relates to the field of removing pollutants in water by coordination chemistry and adsorption, in particular to a cobalt complex monocrystal, a preparation method and application thereof. Background Lead (Pb 2+) is one of the most widely distributed and toxic industrial pollutants, can be accumulated in human bodies for a long time, and causes serious damage to brain, liver, kidney, reproductive system and immune system. In the context of rapid industrial and economic growth, pb 2+ pollution has become an important environmental issue, and almost all countries are concentrating on finding effective strategies for removing Pb 2+ from aqueous solutions. At present, the trapping method of heavy metal ions comprises a chemical precipitation method, an oxidation-reduction method, an electrolytic method, a membrane permeation method, an ion exchange method, an adsorption method and the like, wherein the adsorption method has high efficiency, simple operation and low cost. Trace cadmium (Cd 2+) is also highly toxic in aquatic media and can cause irritation to the respiratory tract, and long-term exposure can cause loss of sense of smell, gum macula, or yellow circles. Although cadmium compounds are not easily absorbed by intestinal tracts, cadmium compounds can be absorbed by bodies through respiration and accumulated in livers or kidneys to cause harm, especially obvious damage to kidneys. To date, a large number of adsorbents such as alumina, zeolite molecular sieves, activated carbon materials, nanomaterials and chelating polymers have been synthesized. Most adsorbents face the challenges of moderate selectivity and low absorption capacity due to lack of structural and functional adjustability. Therefore, in order to realize efficient removal of Pb 2+ and Cd 2+ in aqueous solutions, development of a novel adsorbent with adjustable structure and function has received attention. Metal-organic frameworks (MOFs) are framework structures composed of organic ligands and Metal ions or Metal cluster nodes, and are widely applied in the adsorption field due to the characteristics of high specific surface area, adjustable chemical components, adjustable pore structures and the like (Inorganic Chemistry,2022,61,4,2017-2030). The porous metal-organic framework with specific structure and performance can be modified by selecting a ligand with specific functional groups or synthesizing the porous metal-organic framework so as to have special chemical and physical properties for removing heavy metal ions. Therefore, it is the current direction of research of the present inventors to obtain more active adsorption sites for adsorption removal of Pb 2+ by purposely loading different functional groups (carboxylic acid groups, azo groups, etc.) into the channels of MOFs. The inventor previously issued patent 2022104393339, namely a copper (II) complex monocrystal and a synthetic method and application thereof, which are used as adsorbents for adsorbing and removing lead ions and iodine in water. However, the method has the defects that 1, the adsorption kinetics of the copper (II) complex single crystal to Pb 2+ is slow, the adsorption equilibrium is reached within about 200 minutes, and 2, the copper (II) complex single crystal is easily influenced by interfering ions. Therefore, the inventor further performs research and development of the compound in the later period to realize selective adsorption of various metal ions. Disclosure of Invention The invention aims at providing a cobalt complex single crystal with more active adsorption sites for Pb 2+ and Cd 2+, and also aims at providing a preparation method and application thereof. In order to achieve the aim of the invention, the technical scheme is as follows: The chemical formula of the cobalt complex monocrystal is { [ Co 3L(μ2-O)(DMF)2(H2O)4]·(DMF)3}n, n is a positive integer, belongs to monoclinic system, space group is C2/C, α=90°,β=96.99(3)°,γ=90°,Wherein L represents 5,11,17, 23-tetra [ (m-carboxyphenyl) azo ] -25,26,27, 28-tetrahydroxycalix [4] arene loses four H atoms, and DMF represents N, N' -dimethylformamide. The preparation method of the cobalt complex monocrystal comprises the following steps: Cobalt chloride hexahydrate (0.05 mmol) and H 4 L (0.01 mmol) are dissolved in N, N' -dimethylformamide and distilled water, and are sealed in a reaction bottle, are subjected to ultrasonic treatment at room temperature, are placed in a constant-temperature oven, and are cooled to room temperature, so that red blocky crystals are obtained, namely Co (II) complex single crystals. The complex can be used as an adsorbent for adsorbing and removing Pb 2+ and Cd 2+ in water. The invention has the advantages that the functional groups such as carboxylic acid groups, azo groups and the like are modified in the pore canal of the three-dimensional framework structure of th