磁改性污泥基生物炭对猪粪堆肥及土霉素降解的影响

This study explored the effects of two Fe²⁺/Fe³⁺ concentrations on the properties of magnetically modified sludge-based biochar（MMSB）and its influence on humification and oxytetracycline（OTC）degradation during pig manure composting. Two concentrations of MMSB，MMSB-0.1 with 0.1 mol·L^-1 Fe²⁺/Fe³⁺ concentration and MMSB-0.25 with 0.25 mol·L^-1 were incorporated into pig manure at a mass ratio of 10% （dry weight） for composting. Results revealed that pig manure with MMSB prolonged the thermophilic phase of composting about 1 to 3 days，increased the peak composting temperature about 1.0 to 3.3 ℃ ，and accelerated moisture content reduction by 5.14% to 7.00%. The humification process during composting was significantly improved with adding MMSB. Compared with the control group，the humic acid contents of MMSB-0.1 group and MMSB-0.25 group increased by 18.16% and 10.76% respectively. The humification index values greatly increased by 57.17% and 37.75% for two groups respectively. MMSB shortened the half-life of OTC. The ultimate degradation rates were lower than CK due to the amplification of OTC adsorption facilitated by the Fe₃O₄-loaded MMSB during composting. The pearson correlation analysis and redundancy analysis revealed that the maturity and degradation of OTC were strongly influenced by MC，temperature，and dissolved organic carbon. Adding MMSB，such as MMSB-0.1 group with a lower dose of magnetic modification，can easily control physical and chemical properties，increase maturity degree，and accelerate OTC degradation during pig manure composting. This study presents the fundamental research concepts on the pig manure composting via magnetic modified biochar.