Growth of cobalt based-coordination polymer on the surface of filter paper for fast up-taking of Congo red by simple filtration

Abstract

The grafting of coordination polymers (CPs) to other compounds is a great technique to produce advanced materials with favored properties. Especially, conjugation of the CPs with flexible materials such as filter paper (FP) is anticipated to prepare valuable adsorbents for separation purposes. Herein, a Co-based coordination polymer (Co-CP) with 2-aminobenzene-1,4-dicarboxylic acid (NH2-BDC) as a linker was grown on the surface of functionalized FP to attain CP-paper composite. Chloroacetic acid was used as a surface modifier for improving the adaptability and connection between Co-CP and FP. The terminal COO− groups on the surface of carboxylated filter paper (CFP) operated as connecting groups to coordinate Co2+ cations. Layer-by-layer (LbL) growth ensured complete and homogeneous distribution of the CP on the CFP. The exploited strategy to functionalize FP revealed efficient, selective, and rapid uptake of model pollutants (more than 90% for Congo red, CR) through the simple filtration of CR solution on the obtained CFP/Co-CP as a CP-paper. The kinetics and mechanism and of the uptake by CFP/Co-CP were also demonstrated by the Langmuir isotherm and the pseudo-second-order model represented a very good match with experimental data. The CFP/Co-CP can be simply recovered and reused four times without effective loss of its dye uptake ability.