Facile synthesis of carbon black and sodium alginate based particles system for efficient solar desalination of highly concentrated brine

Interfacial solar desalination of seawater/wastewater is one of the most promising strategies to mitigate the crisis of freshwater shortage. Tremendous progress on improving the evaporation rate has been achieved over the past ten years, however, with the rapid evaporation at the interfacial region of water and air, salt simultaneously aggregates on the solar absorbers, reducing the stability of the evaporative performance. It is essential to design salt-resistant solar evaporators, especially for dealing with highly concentrated brine, in which salt clogging is more likely to occur. Here, we demonstrate a facile and scalable synthesis of self-cleaning particles system by coating carbon black (CB) onto expanded polystyrene (EPS), which can generate freshwater from high salinity brine. With sodium alginate (SA) as a binder, the EPS core-CB shell particles are fabricated by a simple ‘rolling rice dumpling’ strategy. These particles spontaneously gather to a system in water attributing to the surface tension, which function coordinatively to realize the self-cleaning process through rotating ascribed to the unbalanced force after salt crystallization. Benefiting from the low cost of materials, facile synthesis procedure, and good performance in high salinity water, our EPS-CB particles system opens up an avenue for the practical applications of interfacial solar desalination. •A facile and low cost strategy for fabricating self-cleaning solar evaporator.•Excellent salt resistant performance in highly concentrated brine (20 wt% NaCl, saturated NaCl).•Complete separation of water and inorganic solute was realized.