Functional decoration on a regenerable bifunctional porous covalent organic framework probe for rapid detection and adsorption of copper ions

Developing fluorescence porous probe for detecting and eliminating Cu^(2+) contamination in water or biosystem is an essential research project that has attracted considerable attention.However,improving the fluorescence detecting efficiency while enhancing the adsorption capacity of the porous probe is of great challenge.Herein,a bifunctional two-dimensional imine-based porous covalent organic framework(TTP-COF)probe was designed and synthesized from 1,3,5-tris(4-aminophenyl)benzene(TAPB)and 2,4,6-Triformylphloroglucinol(TP)ligand.TTP-COF displayed rapid detection of Cu^(2+)(limit of detection(LOD)=10 nmol·L^(−1) while achieving a high adsorption capacity of 214 mg·g^(−1)(pH=6)at room temperature with high reusability(>5 cycles).The key roles and contributions of highπ-conjugate and delocalized electrons in TABP and functional–OH groups in TP were proved.More importantly,the fluorescence quenching mechanism of TTP-COF was studied by density functional theory theoretical calculations,revealing the crucial role of intramolecular hydrogen bonds among C=N and–OH groups and the blocking of the excited state intramolecular proton transfer process in detecting process of Cu^(2+).

Adsorption of Pb^2+and Cu^2+with Unburned Desulphurization Slag Modified Nickel Slag

Desulphurization slag modified nickel slag adsorbent was prepared by unburned forming technology. The structure of the sample was characterized by BET,XRD,IR,SEM and EDAX. The adsorption performance of Pb^2＋ and Cu^2＋ onto the resultant adsorbent from aqueous solution was studied. Results indicated that the adsorbent possesses a network pore structure formed by the AFt and C–S–H through cross lapping; the adsorbent contains a large number of Si–OH and Al–OH functional groups. The presence of functional groups not only provides abundant adsorption sites for Pb^2＋ and Cu^2＋,but also improves the adsorption performance of Pb^2＋ and Cu^2＋ from waste water through the complexation of heavy metal ions. The result of specific surface area analysis showed that the adsorbent sample possesses mesoporous structure and the BET specific surface area is 27.15 m^2/g. The solution p H values for the adsorption of Pb^2＋ and Cu^2＋ were optimized to be 6 and 5.5,respectively. The adsorption capacities of Pb^2＋ and Cu^2＋ gradually increase,whereas the removal rates of the two metal ions decrease with increasing the initial concentration of simulated solution. The resultant adsorbent gives a higher adsorption capacity for Cu^2＋ than for Pb^2＋ in the single ion solution. However,it shows preferential adsorption of Pb^2＋ rather than that of Cu^2＋. Meanwhile,results of recyclability indicate the remarkable regeneration capacity,re-adsorption ability and reusability performance of the adsorbent sample.

Application of Modified Nickel Slag Adsorbent on the Removal of Pb^(2＋) and Cu^(2＋) from Aqueous Solution

Al（OH）_3 modified nickel slag adsorbent was prepared by sintering technology. The structure of the sample was characterized by BET, XRD, IR, SEM and EDAX. The sample＇s adsorption performance of Pb^（2＋） and Cu^（2＋） from aqueous solution was studied. Results indicated that the adsorbent is a loose and porous mesoporous material. Its surface had mass aluminosilicate, high-activity γ-Al_2O_3 and its p H ranges from 4 to 12 that all have negative charges. The BET surface of the adsorbent is 23.90 m^2/g. Furthermore, its surface contains rich oxygenic functional groups, which could not only provide abundant adsorption sites for Pb^（2＋） and Cu^（2＋）, but also improve the adsorption performance of Pb^（2＋） and Cu^（2＋） from waste water through the complexation of heavy metal ions. The best p H values selected in the adsorption of Pb^（2＋） and Cu^（2＋） are 6 and 5, respectively. With the increase of the initial concentration of simulated solution, the adsorption capacities of Pb^（2＋） and Cu^（2＋） gradually increased but the removal rates showed a downward trend. The competitive adsorption results of Pb^（2＋） and Cu^（2＋） showed that Pb^（2＋） has better preferential adsorption than Cu^（2＋）.