Preparation of RGO-P25 Nanocomposites for the Photocatalytic Degradation of Ammonia in Livestock Farms

Shihua Pu,Jiaming Zhu,Dingbiao Long,Zuohua Liu,Feiyun Yang

doi:10.3390/catal8050189

Abstract

In this paper, the Hummer’s method was used to prepare the compound catalyst of reduced graphene and TiO2 (RGO-P25), and the sand core plate was used as the carrier to provide the theoretical basis for the application of animal environmental purification by exploring the degradation of ammonia in RGO-P25. Characterization results show that the band gap of P25 is reduced from 3.14 eV to 2.96 eV after the combination of RGO, and the recombination rate of the photogenerated electrons and holes also decreased significantly, both resulting in the improvement of ammonia degradation by composite catalysts. Experimental results show that the carrier (sand core plate) and RGO-P25 are effectively stabilized with Si–O–Ti, but the blank core plate carrier could not degrade the ammonia, and its adsorption is not obvious, only 5% ± 1%, under 300 W ultraviolet lamp irradiation, the degradation rates of P25, RGO and RGO-P25 for ammonia at initial concentrations of 119–124 ppm were 72.25%, 81.66% and 93.64%, respectively. P25 dispersed through RGO can effectively adsorb ammonia on the surface to provide a reaction environment and thereby improve its photocatalytic efficiency, thus, endowing the RGO-P25 composites with higher photocatalytic degradation performance than RGO or P25 individually.

Highlights

With the rapid development of China’s aquaculture industry, the scale of livestock and poultry farming has been continuously increasing, thereby resulting in a significant increase in poultry breeding waste and emissions
The scanning electron microscopy (SEM) image in Figure 1d demonstrates that the fritted disc is mainly composed of particulate matters that form a porous structure, which can effectively increase the load and bonding force between the load material and the load base and in turn prevent the loss of reduced graphene oxide (RGO)-P25 in suspension, thereby improving its utilization in the photocatalytic process [33]
The blank sand core plate used in this experiment did not impart a photocatalytic degradation effect on ammonia (Figure 8). These findings indicate that most of the ammonia gas was decomposed by the RGO-P25 catalyst, and the catalytic performance was stable

Summary

Introduction

With the rapid development of China’s aquaculture industry, the scale of livestock and poultry farming has been continuously increasing, thereby resulting in a significant increase in poultry breeding waste and emissions. Environmental pollution from livestock and poultry farming mainly involves malodourous gas pollution and faecal sewage pollution, and causes spread of disease. The smell of livestock and poultry housescomes from the discharged gas, dung manure, faecal transport, and fertilization, including main ammonia, hydrogen sulphide, indole, mercaptan, volatile fatty acids, and hundreds of other toxic and hazardous substances [5,6]. Among these gases, ammonia and hydrogen sulphide are the main components of the odour and are among the odorous pollutants regulated by the state [7,8]

Methods

Results

Conclusion