Abstract
Bioethanol is an important renewable resource that facilitates the sustainable development of society. In Miyako Island, Okinawa Prefecture, bioethanol is produced from sugarcane molasses, but molasses-based distillery wastewater is a highly polluted and dark brown-colored effluent that can cause serious problems in wastewater treatment. In a trial of seven adsorbents to investigate the separation of the colorants from wastewater, Diaion HP20 was selected as the most suitable adsorbent. Adsorbing and desorbing operations using column chromatography with HP20 recovered 74.5% of the colorants from wastewater (33.7 and 40.8% for 20 and 50% ethanol-eluted fractions, respectively). The isolated colorants as well as the wastewater itself exhibited scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH), and contained polyphenols. The distillery wastewater contained 11.3 g-tocopherol equivalent/L of DPPH radical-scavenging constituents and 7.66 g-catechin equivalent/L of polyphenol constituents.
