A low-cost route to the syntheses of microporous cobalt-substituted aluminophosphates by using the waste mother-liquor

In an attempt to synthesize microporous materials with respect to green chemistry, we investigate the syntheses of cobalt-substituted aluminophosphate molecular sieves by a low-cost approach through recycling waste mother-liquors of two layered aluminophosphates Mu-4 and AlPO-IM prepared in the Al(iPrO)3–H3PO4–Tem–TEG system (Tem: diethylamine or imidazole, TEG: triethylene glycol). A Co-substituted aluminophosphate [C8H24N2][Al8Co2P10O40] (denoted CoAPO-CJ51) was obtained with the addition of Co2+ ions into the mother-liquor of Mu-4. Its structure is analogous to zeotype GIS with 20% occupancy by Co2+ ions in the metal site, and the protonated diethylamine molecules are located in the 8-ring channels. Co-substituted aluminophosphate [C3H5N2][Al2CoP3O12] (denoted CoAPO-CJ52) was obtained with the addition of Co2+ ions into the mother-liquor of AlPO-IM. Its structure is analogous to zeotype LAU with 33.3% occupancy by Co2+ ions in the metal site, and the protonated imidazole molecules are located in the 10-ring channels. Both compounds are characterized by single-crystal X-ray diffraction analysis, ICP and TG analyses.