Laser thermal synthesis of reduced graphene oxide/CuS nanocomposites for efficient solar-driven water purification

Utilizing inexhaustible solar energy to realize water purification is a green and sustainable solution to water pollution. Herein, a laser thermal method was adopted to prepare reduced graphene oxide/CuS nanocomposites (rGO/CuS) for solar-driven water purification. By laser treatment of aqueous NaOH solution containing graphene oxide, CuCl 2 , and thiourea, rGO was formed, and CuS was anchored on the rGO surface at an elevated temperature. The prepared rGO/CuS showed high photothermal conversion ability, and the water evaporation enthalpy was reduced for rGO/CuS loaded melamine sponge (rGO/CuS-MS). A notable high solar-driven water evaporation rate of 2.09 kg•m −2 •h −1 was achieved for rGO/CuS-MS under 1.0 kW•m −2 solar irradiation. Integrating with the adsorption ability, the rGO/CuS-MS demonstrated efficient removal capacity of rhodamine B (RhB), volatile m-dinitrobenzene (m-NB), and Ni 2+ in water under solar irradiation. The results indicated that the water evaporation could enhance the RhB, m-NB, and Ni 2+ adsorption capacity of rGO/CuS-MS. Both the unevaporated and distilled water can be efficiently purified by rGO/CuS-MS under solar irradiation. Also, increasing solar flux showed contribution to higher RhB removal ratio for the accelerated water evaporation. This study could contribute to preparing rGO-based nanocomposites for water resources remediation applications.