Role And Multiscale Characteristics Of Graphene Modified Biochar Induced Pig Manure Aerobic Composting

Biochar addition provides an effective pathway to improve composting process and passivate heavy metal during organic wastes composting. However, in general, thc sorption capacity of biochar prepared directly from biomass feedstock without pre-or post-treatments was relatively low. In this study, bamboo biochar (BB), wood biochar (WB), graphene modified bamboo biochar (GBB) and wood biochar (GWB) as mixing agents were utilizated to improve the effectiveness of pig manure composting. as well as to reduce nitrogen loss and heavy metals bioavailability. Results showed that the application of graphene modified biochar induced a more positive effect than unmodified biochar on composting performance. Graphene modified biochar at 50 obviously accelerated the compost into the high temperature period, effectively buffered the pH to around 8, increased the seed germination index by approximately 20%, and provided more microorganisms to improve compost maturity. It also improved the organic matter degradation, increased the NO3-N to over 0.6 g kg and thereby decreased the nitrogen loss. The application of graphene modified biochar further increased the passivation effect of Cu and Zn by above 25%, Interestingly, GWB at 5% showed the best performance in terms of decomposing effectiveness and heavy metal passivation for pig manui-e aerobic composting.