Activation of ordered mesoporous carbon nitride prepared via soft-template for CO2 adsorption

A mesoporous carbon nitride material (MCN) was nanocasted by using a soft-template of triblock surfactant Pluronic F127, a carbon resource from resol and dicyandiamide (DCDA) as a nitrogen precursor. The obtained MCN was activated to improve its porous channel (AMCN). A reference sample of mesoporous carbon (MC) material was also prepared in the same protocol without DCDA. The tunable mesostructures (p6m symmetry) was proved by X-ray diffraction, transmission electron microscopy images and nitrogen adsorption-desorption isotherms. Fourier transformation infrared spectroscopy and energy dispersive X-ray spectroscopy presented about 3.1 wt% of doped-nitrogen in the obtained MCN. In comparison to the MC, a significant increase of BET surface area (333 m2/g for MC, 414 m2/g for MCN and 951 m2/g for AMCN) and an enlargement of pore volume (0.23 cm3/g for MC, 0.25 cm3/g for MCN and 0.33 cm3/g for AMCN), which contributed to a noticeable enhancement of the room temperature CO2 uptake from 1.8 mmol/g (for MC) to 3.7 mmol/g (for MCN) and 4.1 mmol/g (for AMCN). This work emphasized that the assistance of DCDA and further activation resulted in enlargement of both pore volume and BET surface area promising a feasible application of MCN and AMCN in adsorption technology.

Enhanced the Synergistic Effect of Tetracycline Adsorption and Photocatalytic Degradation on a Novel Mesoporous Carbon Nitride

A novel mesoporous g-C3N4 with guanidine hydrochloride as precursor was prepared by molten salt assisted hard template of silica (SiO2) aerogel for photocatalytic degradation of tetracycline (TC). The textural structure, chemical composition, morphology and optical properties of mesoporous g-C3N4 were characterized by a series of means, and the synergistic effect of adsorption and photocatalytic degradation of TC was elucidated. The results show that the successfully synthesized mesoporous g-C3N4 presented a coral-like rod shaped and heptazine ring structure. When the amount of SiO2 aerogel template was 1.4 g, the richer nitrogen defects of the sample (GM-1.4) with the lower band gap (2.42 eV) was displayed.The photocatalytic degradation rate of GM-1.4 for TC was reached to 83.4% under visible illumination for 120 min. Furthermore, the •O2- and h+ were proved to be the main active species, and the reasons of TC photodegradation were associated with the destruction of TC molecular structure.

Preparation of Non-polluting Tb-Doped Mesoporous Carbon Nitride Photocatalyst and Study on the Efficacy and Mechanism of Degradation of Antibiotics in Water

Given that the biological treatment of antibiotic wastewater can easily induce resistant bacteria, the photocatalytic degradation of antibiotics is considered a better method for treating antibiotic wastewater. Therefore, the ability to remove Tylosin (TYL) and Tetracycline (TC) in aqueous solution using rare earth element Tb-doped g-C3N4 under simulated natural solar radiation was investigated. A series of rare earth Tb3+ doped mesoporous g-C3N4 were successfully prepared by nitric acid treatment and Tb(NO3)3·5H2O samples showed significantly higher degradation efficiency for TYL and TC than pure g-C3N4. Leaching toxicity experiments were carried out on the catalyst using chard seeds and demonstrated negligible toxicity of the leachate from the catalyst. The structure, elemental state, optical properties, morphology and photogenerated carrier separation of the prepared xTCN catalysts were characterized by XRD, XPS, UV-Vis DRS, TEM and PL. The results showed that Tb doping enhanced the photocatalytic activity of the g-C3N4 catalyst by narrowing the band gap while improving the light-trapping ability; The separation and transport rate of photogenerated carriers were significantly increased after Tb doping. Finally, a simple, efficient and non-polluting Tb-doped carbon nitride photocatalyst is successfully developed in this paper.