The feasibility of foam separation for color removal from direct dyes-containing wastewater was assessed
using actual textile wastewater as the research system and cetyl trimethyl ammonium bromide (CTAB) as
the collector. The influences of liquid loading volume, air flow rate, surfactant concentration, and initial
pH on the removal efficiency and reuse of CTAB in the foamate were studied. The results indicated that
using CTAB as a collector for foam separation can provide good foaming quality and effectively remove
color from textile wastewater. Under optimum operational conditions (liquid loading volume 450 mL,
gas flow rate of 500 mL/min, CTAB concentration 20 mg/L, and an initial pH of 7.0), the removal efficiency
reached 88.9%. The residual dye content met the discharge standard for the dyeing and finishing textile
industry (GB4287-92) published by the Ministry of Environmental Protection of the People’s Republic of
China. Using recycled foamate in untreated wastewater, the removal efficiency of 87.5% was obtained
with CTAB concentration 10 mg/L of the wastewater.