Improved methanogenesis in anaerobic wastewater treatment by magnetite@polyaniline (Fe3O4@PANI) composites

The magnetite@polyaniline (Fe 3 O 4 @PANI) composites with different Fe 3 O 4 loadings were prepared, and their effect on methane production in anaerobic systems was investigated. The Fe 3 O 4 @PANI composite with a 40% loading of Fe 3 O 4 showed a better performance on accelerating methane production rate than other composites. The methane production rate was increased by 26.98% at the Fe 3 O 4 @PANI dosage of 0.6 g L −1 . The results of the contact angle and CLSM revealed that Fe 3 O 4 @PANI had a good bio-affinity and contact directly with bacteria and archaea. Then the mechanisms related to the enhancement of methane production by the composites were explored by the species annotation and enzyme activity . It showed that Fe 3 O 4 @PANI promoted the enrichment of DIET-related functional bacteria and archaea and improved the enzyme activity related to the acetoclastic methanogenic pathway.