| Degradation of CPs is one of the greatest world-wise challenges in the environmental purification, because of the high toxicity, bioaccumulation and persistence, etc. Treatments of physics and chemistry are either high-cost or low efficiency, hence some investigators recently has turned to the rising photocatalysis technique hoping to gain the breakthroughs of environmental purification and clean energy utilization. In this study, metal doped ordered mesoporous carbon(C) composites was synthesized by combining the efficient adsorbent nickel doped ordered mesoporous carbon with the superior photocatalyst graphite carbon nitride(g-C3N4). The composites were characterized by XRD, BET, FESEM, TEM and UV-Vis techniques, and, the adsorption activities of nickel doped ordered mesoporous carbon were studied, so did the photocatalytic activities of g-C3N4 and g-C3N4/C materials. Intermediate products generated during the photodegradation of 2.4-dlchlorophenol(2.4-DCP) were analyzed by HPLC and GC-MS methods, and the degradation pathway and mechanism were proposed.Main conclusions of this paper are summarized as below:(1) Nickel doped ordered mesoporous carbon materials were synthesized in EISA(Evaporation Induced Self-Assembly) way by using commercial surfactant triblock copolymer F127 as soft-template, alkaline phenolic resin as carbon precursors, nickelous nitrate as metallic compounds. Results of XRD, BET and TEM Characterization indicated that mesoporous carbon owned well-ordered mesoporous structures, high specific surface area and pore volumes. Adsorption tests of Rhodamine B(Rh B) showed that as-achieved carbon materials had fast adsorption rate and high loading capacity, and the process was well-fitted with the pseudo second-order rate equation and Langmuir adsorption isotherm.(2) Graphite carbon nitride was achieved by thermal treatments of the cheap and convenient melamine at different temperatures, XRD, SEM and UV-Vis characterization results showed as-synthesized g-C3N4 had well-maintained graphitic stacking structures and strong response abilities of visible light. The catalytic test results of Rh B solution indicated that the sample calcined at 580 ℃ had the highest photocatalytic activities under the irradiation of both visible-light and sun-light.(3) Nickel doped ordered mesoporous carbon composites were synthesized by low-temperature thermal treatment of the mixtures of as-prepared C and g-C3N4 materials. XRD, SEM and UV-Vis characterization results indicated that as-achieved samples had high specific surface area and strong visible-light response abilities, catalytic test results of Rh B showed that sample g-C3N4/C-4 had the highest photocatalytic efficiency and removal rate, which had 4 wt% of mesoporous carbon.(4) The g-C3N4/C-4 composites showed the highest photocatalytic ability with degradation rate up to 95.25%, which was much higher than pure g-C3N4, in concentration of 2.4-DCP 20 mg/L under conditions of 0.5 g/L and illumination time of 240 min.(5) Photocatalytic degradation of 2.4-DCP products were found through analysis that C-Cl bond on benzene ring was oxidized and then fractured by hydroxyl radical from photocatalyst,Cl substitute became free-Cl existing in the solution,2.4-DCP was degraded by ?OH and generated intermediate product of small molecule organic,and small molecule organics were further degraded under photocatalysis. Through kinetic analysis of reaction La-S-Ti O2/SBA-15 catalysis on degradation rate of 2.4-DCP followed first-order reaction. |
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