Coordination polymer derived Ni based composite material with N-doped mesoporous carbon as matrix for pollutants removal

Abstract

To obtain a magnetic composite material for water treatment, a Ni based composite material with nitrogen doped mesoporous carbon as matrix (Ni@NC) has been synthesized with coordination polymer as precursor. In Ni@NC, Ni nanoparticle with the size about 3–5 nm dispersed evenly in nitrogen doped mesoporous carbon matrix. Ni@NC exhibits striking catalytic activity in reductive conversion of 4-nitrophenol to 4-aminophenol with the existence of sodium borohydride (NaBH4). The conversion efficiency reaches almost 100% in 160 s with the amount of Ni@NC as low as 5 mg. After eight successive cycles of reductions, the efficiency still retains above 99%. For a catalyst, chemical content plays an important role in its performance. Here, the influence of nitrogen species on 4-nitrophenol reductive property is discussed in detail, which illustrates pyrrolic N and quaternary N both play significant roles during catalytic reduction process. In addition, Ni@NC also possesses excellent activity in catalytic reduction of organic dyes, such as Rhodamine B (RhB), methyl orange (MO) and methylene blue (MB). Due to its large surface area and suitable pore size, Ni@NC also possesses adsorption removal property towards tetracycline and Cr2O72−. Magnetic measurement reveals ferromagnetic character of Ni@NC, which facilitates its magnetic separation from the treated samples. All these merits make Ni@NC a promising multifunctional environmental material in waste water treatment.