Water desalination and highly efficient solar evaporation using the ferrite SnFe2O4/PVA: GA: AC hydrogel nanocomposite: Physical and photo-chemical properties

This study designs a novel tin ferrite (SnFe2O4)/PVA: GA: activated carbon (AC) hydrogel evaporator material for solar water desalination. This approach addresses challenges in traditional seawater desalination, such as increasing the evaporation efficiency, the detrimental influence of condensed water droplets and water vapor on light absorption, and the difficulties in efficiently obtaining clean water. The PVA: GA: SnFe2O4/AC nanocomposite hydrogel was synthesized by dispersing SnFe2O4 nanoparticles and activated carbon (AC) in polyvinyl alcohol (PVA) and cross-linking it with glutaraldehyde (GA). The structural, optical, and morphological properties of the synthesized nanocomposite hydrogel were characterized using X-ray diffraction (XRD), UV–Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FESEM). Fresh water preparation and solar evaporation experiments were performed in the presence a simulated the sunlight by an IR lamp (250 W, 2300 K), with intensity 2094 LUX. The synergistic photothermal and microporous properties of the nanocomposite hydrogel enabled an impressive evaporation rate of 3.85 kgm−2h−1. Total dissolved solids (TDS) and inductively coupled plasma (ICP) analyses confirmed excellent salt resistance. Furthermore, distillation of Caspian seawaters significantly reduced the concentration of K+, Mg2+ Na+, and Hg2+ ions. Water hardness decreased from 6648 ppm to 213 ppm, and conductivity was reduced from 8651 µS/cm to 453 µS/cm, both complying with World Health Organization (WHO) standards. This work offers a promising avenue for further research to enhance the availability of drinking water in urban and rural communities through solar evaporation technology.