Carbonized balsa wood–based photothermal evaporator for treating inorganic chemical wastewater

Abstract

Solar desalination provides a sustainable and eco-friendly solution for purifying wastewater, addressing environmental challenges associated with wastewater treatment. This study focuses on the purification of inorganic contaminants from laboratory chemical wastewater (ICWW) using a spherical solar still (SSS). To enhance the evaporation rate and overcome the impact of heavy metals on absorption efficiency, a carbonized balsa wood (CBW) solar evaporator was employed. Balsa wood pieces, carbonized at 250 °C for 15 min, were arranged in a SSS configuration. The CBW-integrated SSS demonstrated a remarkable freshwater productivity of 2.33 L/m2 for ICWW, surpassing the conventional SSS, which produced only 1.5 L/m2. The presence of heavy metal ions (Na+, Ca+, K+, and Mg2+) in ICWW significantly affected the evaporation rate, and the CBW solar evaporator exhibited an impressive removal efficiency of approximately 99%. Water quality parameters, including pH and chemical oxygen demand (COD), were investigated before and after treatment. The CBW-integrated SSS achieved an outstanding COD removal efficiency of about 99.77%, reducing the COD level from 229.51 to 0.521 mg/L. These results underscore the efficacy of the proposed solar desalination system in purifying ICWW, offering a promising approach to address environmental concerns associated with wastewater treatment.