A Scalable Prototype by In Situ Polymerization of Biodegradables, Cross-Linked Molecular Mode of Vapor Transport, and Metal Ion Rejection for Solar-Driven Seawater Desalination

Abstract

Water scarcity in mass populated areas has become a major global threat to the survival and sustainability of community life on earth, which needs the prompt attention of technological leadership. Solar evaporation has emerged as a renewable energy resource and a novel technique for clean water production and wastewater treatment. Indeed, mounting a scalable solar evaporator including high evaporation efficiency and thermal management remains a significant challenge. Herein, we demonstrate a self-floatable, ecofriendly polypyrrole/wood sponge-based (PPy@WS) steam generator. The low-cost and easy to fabricate evaporator system consists of a single-step in situ polymerization of a 2-D (two-dimensional) hydrophilic wood sponge abundantly available for commercialization. The as-prepared PPy@WS solar evaporator exhibits excellent wettability and is super hydrophilic (contact angle ∼ 0), salt-resistant, and has an excellent light absorption of ∼94% due to omnidirectional diffusion reflection in PPy Nanoparticles (NPs). The capacity of the PPy@WS evaporator to absorb broadband solar radiation and convert it into thermal energy has enabled it to achieve excellent surface temperature (38.6 °C). The accumulated heat can generate vapors at the rate of 1.62 kg·m−2·h−1 along with 93% photothermal conversion efficiency under one sun (1 kW·m−2). Moreover, the presented prototype possesses the capability to be installed directly without the use of any complex protocol to purify seawater or sewage with an efficient rejection ratio of primary metal ions present in seawater (approximately 100%). This simple fabrication process with renewable polymer resources and photothermal materials can serve as a practical model towards high-performance solar evaporation technology for water-stressed communities in remote areas.

Keywords

• desalination
• in situ polymerization
• solar steam generation
• wood pulp