Solar Distillation for Desalination Purposes: Application of Alternative and Technological Materials for the more Efficient Production of Drinking Water.
Solar still; renewable energy; fresh water; Brazilian semiarid.
The water crisis is a global concern whose aggravation makes the desalination of oceanic waters and other saline reservoirs reasonable. In Brazil, the reality of drought has led the Federal Government to create the Water Sweet Program (PAD), among other measures. The PAD proposal is to recover, deploy and manage reverse osmosis systems in rural semi-arid communities. However, after seven years, only 47.6% of the initial target is fully operational. In line with the objectives of the PAD, with the privileged offer of solar energy and with the vast literature that reports the advantages of the use of solar distillers for the conditions like those found in Brazil, the objective of this work is to investigate materials that promote the increase of productivity equipment. For this, tests were carried out in an environment with real and simulated irradiation, investigating mainly the effects of alternative and technological materials in the composition of collector plates and in the improvement of the optical and thermal properties of the brine on the rate of evaporation. The photo-assisted evaporation tests using nanostructured CoFe2O4 presented reproducibility higher than 99% and increased the evaporation rate by 13.8% with respect to reference, and the residual ash plate promoted an effective gain of 18.2%. The solar evaporation tests recorded rates 60.7% higher with theoretically inert plate, painted externally with black commercial paint, suggesting accumulated close to 4.0 kg/m2 in only 3.5 h of sun exposure. Thus, the studies show that the construction of solar stills that meet the inalienable assumptions of low cost, efficiency and safety to exempt contaminants in the distillate, are possible to mitigate the effects of drought in the Brazilian semiarid.