3D Porous Photothermal Materials for High Salt Wastewater Treatment

Abstract

The treatment of high salinity wastewater is complex with high cost and energy consumption. Interfacial solar vapor generation technology because of its green, high efficiency and low energy consumption has become a hot spot in the field of water resource recovery and utilization. In this study, a novel three-dimensional porous graphene composite material (3D h-CN/r-GO) was designed by a hydrothermal reaction with fibrous carbon nitrogen (h-CN) modified graphene (r-GO), and its performance for adsorption of nitrobenzene and phenol as simulated contaminants via photothermal evaporation was studied. The results showed that 3D h-CN/r-GO has a broad-spectrum absorption and multistage channel structure and presents the characteristics of fast thermal response. Its light steam conversion efficiency can reach 90.4% under the condition of simulated sunlight. The adsorption of nitrobenzene, phenol, and other common volatile pollutants can be realized in the process of treatment, and its adsorption capacities of nitrobenzene and phenol were 67.6 mg·g-1 and 57.5 mg·g-1, respectively. Moreover, 3D h-CN/r-GO can realize efficient interfacial solar vapor generation with long-time stability, and its retention rate of pollutants and salts is up to 98%. The recovery and utilization of steam condensate meets the discharge standard. Therefore, this study provides a promising way for the treatment of high salinity wastewater with low energy consumption and cost.