Carbonized sawdust/barium titanate composite solar absorber for solar driven seawater desalination

A low cost and feasible fabrication of novel photothermal conversion material and solar absorber was widely studied for enhanced solar-to-vapor performance in solar driven vapor generation. In this work, a novel hybrid carbonized sawdust/barium titanate composite was fabricated by sol-gel method, where it was later incorporated with a cotton towel using a dip-coating process to produce a solar absorber. The solar driven seawater desalination setup was made up of i) solar absorber where heat was localized and the evaporation occurs, ii) thermal insulation using polystyrene foam and air gap to minimize the heat loss, and iii) water pathway for continuous supply of seawater to the solar absorber. Carbonized sawdust/barium titanate composite solar absorber was tested under direct solar radiation for about 2 h using seawater collected from the beach coast of Universiti Malaysia Sabah, where it was repeated three times to observe the stability of the solar absorber. The average efficiency of the carbonized sawdust/barium titanate composite solar absorber was about 72.04% with average evaporation rate of 1.32 kg/m(2) h. Salinity of the clean water was significantly reduced about 99.8% from the initial seawater salinity at 29300 ppm to 50 ppm, and the pH value was observed at 7.40. The salinity and pH value of the generated clean water was within the safe water limit based on the World Health Organization (WHO) standard.

Automated summary

A low cost and feasible fabrication method for a novel photothermal conversion material and solar absorber was developed and applied in solar driven vapor generation and seawater desalination. The experimental results showed that the solar absorber had high efficiency and evaporation rate, and could effectively reduce the salinity of seawater and maintain a suitable pH value.