Mechanism for the effects of carbonization temperature on the structure of pig bone biochar and tetracycline catalytic degradation performance

Abstract: Tetracycline (TC) can easily lead to persistent environmental toxicity via bio-enrichment effects, due to the inefficient bio-absorption, high solubility, and high bio-activity. Advanced oxidation processes based on sulfate radicals (SR-AOPs) can be expected to serve as an alternative means. Green low-cost biochar (BC) can be also used as an uneven catalyst. The persulfate (PS) was efficiently decomposed to generate the high-oxidation to restore power free radicals (OH, and SO4-·) during the degradation mineralization of organic matter. In addition, the annual waste bone production has reached 1348 tons in 2021 in China. Traditional treatments of waste bone can also be limited in the implementation conditions or cure such defects as bacterial reproduction. The waste bone can be prepared to catalyze the PS degradation TC. There are different properties of thermal temperature, crystallization, and surface shape made of BC, leading to the removal performance of pollutants. In this study, the different structures of pig bones coal with cooking pig bones were prepared as the raw materials at different temperatures of thermal resolution from 500 ℃ to 900 ℃. Energy spectroscopy was selected to analyze the effect of heat resolution on the pig bone's carbon shape, active phosphorus (hydroxyapatite, HAP) crystal structure, oxygenic acid, as well as the active functional units and cavity structure. Then, the material performance was compared to determine the optimal material pH, and PS parameters impact. The optimal system was achieved in the active oxygen sudden extinction to investigate the interaction between bone carbonization temperature and structure for the catalyst degradation performance. The results showed that there was a noticeable carbonization structure of the pig's bone with the change in the carbonization temperature, indicating three distinct structures of layered cracks, needle-shaped clusters, and empty heart balls at three supply temperatures. Compared with 500 ℃ and 900 ℃, the crystalline structure formed at 700 ℃, and the fully volatile organic components presented the 700BPBC surface calcium phosphorus in the high-temperature formed crystal and the sp2 structural carbon frame in the pig coal combined to form the needle-shaped fiber structure in the form of cluster. The more fine and shorter narrow conveyor was formed with a more microporous structure and better crystal comparison of phosphatic minerals. Energy and infrared spectrum analysis showed that the non-crystalline transformation was significantly influenced by the thermal resolution temperature, and then the content of C, O, Ca, and P, due to the full splitting of organic collagen and inorganic phosphorus and crystalline composition in HAp. As such, the 700BPBC was superior to the other two kinds of pig bone biochar with the rich -OH and active CHAp. The catalytic degradation experiment showed that the degrading capacity order from large to small is 700BPBC, 500BPBC, 900BPBC. Among them, the 700BPBC shared a stronger performance of catalytical degeneration for the TC, due to the small, narrow conveyor, rich active functional agglomeration spots, and better crystalline comparison. Furthermore, the ion form of quercetin was easier to capture than pig coal, when the solution environment was weakly acidic (pH value is 5). The best activity was achieved in the free radicals produced by sulfate (PS). The moderate overdose of sulphate (BC:PS = 1:6) produced the most effective free radical. The OH contributed the most under the 700BPBC/PS system. The free radical reaction was the dominant pathway to catalyze the degradation reaction. There were active CHAp and C=O-induced non-free radical reactions.