Synthesis of Biochar-Supported K-doped g-C3N4 Photocatalyst for Enhancing the Polycyclic Aromatic Hydrocarbon Degradation Activity.

Fayun Li,Meixia Lin

doi:10.3390/ijerph17062065

Abstract

The development of novel and green photocatalysts have attracted considerable attentions due to their excellent performance for environmental remediation, especially for the degradation of persistent pollutants. In this work, the biochar-supported K-doped g-C3N4 composites with the high photocatalytic activity under visible light irradiation was prepared by the calcination-impregnation method. The crystal structure, apparent morphology and functional group composition of the as-prepared photocatalytic materials were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscope (FTIR). Moreover, the characterization of UV-Vis diffuse reflectance spectra (UV-Vis DRS) and photoluminescence technique (PL) verified the good optical properties of resultant samples. Naphthalene was selected as the representative compound to evaluate the photocatalytic performance of the prepared photocatalysts under visible light irradiation. The evaluation results showed that the biochar-supported K-doped g-C3N4 composites exhibited excellent photocatalytic activity (82.19%). Moreover, the photocatalytic degradation rate basically remained unchanged after five cycles, indicating the good stability of the prepared photocatalysts. In addition, a possible mechanism for the photodegradation process was proposed on the basis of the main intermediates detected by gas chromatography-mass spectrometer (GC-MS). This study may provide a promising approach for the polycyclic aromatic hydrocarbon degradation by waste utilization of agricultural biomass and increasing the photocatalytic performance of pure g-C3N4.

Highlights

The pollution of petroleum hydrocarbons is one of the environmental problems in the petrochemical industry in recent years [1]
Petroleum hydrocarbons are complex mixtures composed of alkanes, olefins and polycyclic aromatic hydrocarbons (PAHs)
The biochar, as electron transfer channels and acceptors, effectively inhibited the recombination of photogenerated electron-hole pairs and had a large number of surface hydrophilic functional groups, which could effectively improve the dispersion of the prepared composite photocatalytic materials in polar solvents such as water and further improve the photocatalytic performance

Summary

Introduction

The pollution of petroleum hydrocarbons is one of the environmental problems in the petrochemical industry in recent years [1]. Petroleum hydrocarbons are complex mixtures composed of alkanes, olefins and polycyclic aromatic hydrocarbons (PAHs). Petroleum hydrocarbon leakage may cause serious and persistent water and soil pollution. Due to petroleum hydrocarbon contamination, the quality and visibility of water body decrease, and the fertility and water-holding capacity of soil are reduced [2]. PAHs have the characteristics of high toxicity, mutagenicity and carcinogenicity [3]. PAHs deposited in soil and groundwater pose a tremendous threat to the entire ecosystem. Naphthalene, as a representative substance of polycyclic aromatic hydrocarbons (PAHs), has been classified as a priority control pollutant by the Environmental Protection

Methods

Results

Conclusion