Pretreatment of black liquor from refined cotton production by acidification and adsorption using activated carbon fiber
酸析-活性炭纤维吸附预处理精制棉黑液

Acidification and activated carbon fiber (ACF) adsorption were investigated for removal of organic pollutants from black liquor generated from refined cotton production. Acidification is to remove lignin, while ACF adsorption is to remove the remaining organic matters from black liquor. UV-vis spectroscopy, FTIR were used to evaluate the chemical changes of black liquor. The acute toxicity of black liquor before and after adsorption was evaluated by bacterial bioluminescence assays. The results indicated that the main organic components of black liquor are guaiacyl (G-) and hydroxyphenyl (H-) lignin. When pH=2.0 for acid precipitation, ACF dosage was 90 g/L, 85% of COD could be removed after 5 h of adsorption at 40°C. The adsorption process can be described by Redlich-Peterson isotherm model. The kinetic data followed the pseudo-second-order equation and the adsorption process was endothermic. After acidification and ACF adsorption, up to 95% of the acute toxicity of black liquor was removed, which may be favorable for further biological treatment.