Simultaneous disintegration of municipal sludge and generation of ethanol with magnetic layered double hydroxides

In order to investigate the effect of magnetic ZnCaFe-layered double hydroxides (MLDH) on the disintegration of municipal sludge and generation of ethanol, the MLDH was synthesized for use in the treatment of municipal sludge. The results indicated that the disintegration performance of municipal sludge was obviously enhanced by the MLDH under visible light irradiation, and the MLDH could also improve saccharification and fermentation in the dark. The yields of 468.9 mg/g for reducing sugar and 136.3 mg/g for ethanol were achieved respectively when the MLDH was 0.3 mg/mL, pretreatment time was 80 min, simultaneous saccharification and fermentation (SSF) time was 120 h, and enzyme loading was 60 FPU/g. The conversion yields were still higher than that of control group after 6 cycles of the MLDH. Therefore, the recyclable MLDH is promising for the treatment and energy conversion of municipal sludge.