Environmental effects and enhancement mechanism of graphene/tourmaline composites

Abstract Through releasing negative ions and infrared radiation, tourmaline can absorb dust and hazardous substances to purify air. The purpose is to improve the air purification efficiency of tourmaline through the remarkable electrical properties of graphene. The efficient preparation method of graphene/tourmaline composite was proposed. The environmental properties of the graphene/tourmaline composites, such as infrared radiation and negative ion release, were systematically analyzed. The Hall effect was used to reveal the enhancement mechanism of graphene on tourmaline. This laid a solid foundation for the application of composites in the air purification fields. The results demonstrated that graphene could significantly enhance the environmental effect of tourmaline. The ball milling method was the optimum preparation method, and the parameters were determined as follows: ball milling speed = 200 rpm and ball milling time = 2 h. The optimum graphene content was 0.5% of the mass of tourmaline. The negative-ion release performance of graphene/tourmaline composites was higher than that of tourmaline by over 11.9%. The infrared emissivity and negative-ion release of graphene/tourmaline composites were observed to be significantly correlated with the band gap. The main reason for the enhancement in the environmental properties of tourmaline by graphene was that the band gap of tourmaline was reduced when graphene was compounded with tourmaline.