Abstract: <SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: "Times New Roman"; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">Microwave acid activated red mud was adopted as absorbent for the adsorption and decoloring<SPAN style="mso-spacerun: yes">&nbsp; </SPAN>treatment of scarlet dyestuff wastewater.Influences of factors,such as adsorption time,pH,dosage of absorbent,on decoloring effect were investigated.Results indicated microwave acid activated red mud could successfully remove 97.7% of acid scarlet when optimum technological conditions were as follows:pH of wastewater was 4.0,absorbing time was 2 h,and absorbent dosagewas 15 g/L.Experiment data were fitted with relevant mathematical models and results indicated isothermal adsorption equilibrium was in accord with Langmuir model;and adsorption process kinetics met pseudo-second-order reaction rate equation,with good linear correlation coefficient. </SPAN>