Design of Biomass Network Cellulose Aerogel for Heavy Metal Wastewater Purification Driven by Solar Energy

As a green and low-energy water treatment technology, solar-driven interface evaporation technology is widely used in seawater desalination, power generation and wastewater treatment systems. Here, we developed a three-dimensional sponge as a solar evaporator by introducing a composite hydrophilic polymer (konjac glucomannan, KGM) and a solar absorber (reduced graphene oxide, rGO) into the polyvinyl alcohol (PVA) networks, building biomass-derived aerogel evaporator in a cost-effective fashion. Under one sun, the sponge achieved a rapid evaporation rate (1.61 kg m−2.h−1) and a high interface water evaporation efficiency (93.60 %). Due to the peculiarity of rGO, KGM and PVA, the sponge had the characteristics of adequate water transport, effective water activation, and anti-salt-fouling function. Moreover, it can simultaneously remove heavy metal ions and organic dyes from wastewater, the concentration of heavy metals (Cr3+, Mn2+, Cu2+, Zn2+, Pb2+) in wastewater can be purified from grams to micrograms. In addition, the durability and repeatability character of the sponge also had been verified. The results showed that the interfacial evaporation driven by solar energy based on composite sponge can treat heavy metal ions and organic dyes repeatedly and effectively. It is expected that this study will provide new ideas for solving the problem of water shortage.