Solar evaporation enhancement using floating light-absorbing magnetic particles

Abstract

We have demonstrated a new strategy for enhancing solar evaporation by using floating light-absorbing materials. Floating Fe₃O₄/C magnetic particles with an average size of 500 nm were synthesized by carbonization of poly(furfuryl alcohol) (PFA) incorporated with Fe₃O₄ nanoparticles. The Fe₃O₄/C particles had a BET surface area of 429 m² g⁻¹, and a density of 1.44 g cm⁻³. Because of their hydrophobicity and a bulk packing density of 0.53 g cm⁻³, Fe₃O₄/C particles were floatable on water. Our results indicated that these Fe₃O₄/C particles enhanced the water evaporation rate by as much as a factor of 2.3 in the solar evaporation of 3.5% salt water. In addition, Fe₃O₄/C particles were easily recycled using a magnet, and stable after being recycled three times. Our work provides a low-cost and highly effective way for accelerating solar evaporation for industrial applications such as solar desalination, salt production, brine management and wastewater treatment.