초록
<P><B>Abstract</B></P><P><B>BACKGROUND</B></P><P>A major cost in acid‐catalysed hydrolysis of biomass to fermentable sugars is the consumption of acid itself. In this study, a combined process was developed in which the acid and sugar in the hydrolysate were separated using an acid retardation process and then the dilute aqueous product streams were concentrated using a continuous‐effect membrane distillation (CEMD) process, thus acid could be reused as catalyst.</P><P><B>RESULTS</B></P><P>The recovery rate of sugar was as high as 94.3–99.2% while the recovery rate of sulfuric acid was 92.4–98.9%. The eluents were further concentrated using the CEMD process. When a solution of 2 wt% sulfuric acid was concentrated to <I>c</I>. 40 wt%, the maximum value of permeation flux (<I>J<SUB>w</SUB></I>) and gained output ratio (<I>GOR</I>) was 6.20 L m<SUP>−2</SUP> h<SUP>−1</SUP> and 15.50, respectively. Meanwhile, the dilute aqueous sugar solution obtained from corn stover was concentrated 20‐fold to a final concentration of <I>c</I>. 497.6 g L<SUP>−1</SUP> using the CEMD process with a final <I>GOR</I> of 5.5.</P><P><B>CONCLUSION</B></P><P>The combination of acid retardation and CEMD is suitable for the production of sugar, further purification and concentration of eluents; the sugar solution can be used for fermentation and acid solution can be reused as catalyst. © 2015 Society of Chemical Industry</P>