基于改性氮化硼吸附的污泥焚烧烟气重金属脱除和细颗粒物成核抑制机理研究

Sewage sludge incineration is one of the optimization technology for its high efficiency and speed. But, it is necessary to pay more attention to the pollution of heavy metal and fine particles in flue gas. Then, the cooperative control of the heavy metal removal and the nucleation inhibition of fine particles become a difficulty and hotspot in the sludge incineration pollution control. In this project, a novel efficient adsorbent-active boron nitride (BN) was introduced to this field for its strong thermal stability and regenerability, it was also be doped with S, P2O5 to form active site..The project focuses on the adsorption inhibition mechanism of modified BN on fine particle nucleation precursor (heavy metal, gas phase Ca, SiO or other suboxides). Firstly, the synergetic adsorption efficiency of modified BN on fine particle nucleation precursors was studied by theoretical means of quantum mechanics and chemical thermodynamics, validated with fluidized bed incineration experiment, ELPI fine particle sampling and ICP/XRD/FESEM-EDX/EXAFS. The adsorption kinetics of modified BN on fine particle nucleation precursors was studied by molecular dynamics and quantum mechanics method combined with simulated adsorption experiment of flue gas system. Finally, a comprehensive control effect model of heavy metal toxicity was established, and the synergistic removal technology of heavy metal and fine particles was evaluated and optimized..The research is helpful to expand the application area of BN adsorbent, improve the theoretical system of synergistic removal of heavy metals and fine particles, and provide theoretical guidance for the formation of new methods of synergistic control of heavy metals and fine particles.

快捷高效的焚烧方法是污泥处理优选技术之一，烟气重金属脱除与细颗粒物生成抑制是该技术污染控制的难点和研究热点。本项目将耐高温、易再生高效吸附剂-活性氮化硼引入该领域，通过掺杂S、P2O5形成活性位。项目重点研究改性氮化硼对细颗粒物成核前驱体(重金属、气相Ca以及SiO等次氧化物)的吸附抑制机理。首先采用量子力学、化学热力学理论方法，结合ELPI细颗粒物在线采样，ICP/XRD/FESEM-EDX/EXAFS等手段研究改性氮化硼对细颗粒物成核前驱体的协同吸附效能；运用分子动力学、量子力学方法，结合模拟烟气系统吸附动力学实验，研究改性氮化硼对成核前驱体的界面吸附动力学；最后建立重金属毒性综合控制效能模型，对重金属和细颗粒物协同脱除技术进行评价优化。该研究有利于拓展活性氮化硼吸附剂应用领域，完善固废焚烧烟气重金属和细颗粒物协同脱除理论体系，为形成新型重金属与细颗粒物协同控制技术提供理论指导。

高效的焚烧方法是污泥处理优选技术之一，烟气重金属脱除与细颗粒物生成抑制是该技术污染控制的难点和研究热点。本项目将耐高温、易再生高效吸附剂-活性氮化硼引入该领域，通过掺杂S、P2O5形成活性位，重点研究改性氮化硼对细颗粒物成核前驱体(重金属、气相Ca以及SiO等次氧化物)的吸附抑制机理。. 项目利用前驱体法制备改性氮化硼，材料比表面积高达765.67 m2/g，在吸附反应温度为400 ℃时改性氮化硼对高温烟气中重金属的吸附总量达到57.17 mg/g，是活性炭吸附剂吸附量的3.9倍，是普通氮化硼的10倍以上。并且发现改性氮化硼对于Zn具有极强的吸附选择性，最高吸附量达32.74mg/g。. 项目通过掺杂活化的方式制备出的P-BN样品，含磷量＞30mg/g，具有837.08m2/g的最大比表面积。通过重金属烟气的混合吸附实验，发现P-BN对于重金属的选择吸附能力的顺序为Zn＞Cu＞Pb＞Cd＞Cr，对于重金属Zn具有45.33mg/g的吸附量。通过TG-DSC的解析分析和动力学的模拟分析，发现P-BN对于重金属Zn、Cu的吸附过程中存在物理吸附和化学吸附两种吸附方式。. 项目研究发现活化改性BN对细颗粒前驱体（SiO等）有一定的吸附能力，但其吸附量远小于重金属。活化改性BN对细颗粒前驱体的吸附能力在高温环境保持较好状态，在200℃温度下达到0.304mg/g的最大吸附量，且在300℃的较高温度下也可以达到0.276mg/g的较高吸附量。. 项目研究发表高水平论文4篇，其中SCI收录期刊论文2篇，EI收录中文期刊论文1篇；申请国家发明专利4件，授权1件；培养硕士毕业生4人，项目组成员晋升教授1人，副教授1人。项目研究有利于拓展活性氮化硼吸附剂应用领域，完善固废焚烧烟气重金属和细颗粒物协同脱除理论体系，为形成新型重金属与细颗粒物协同控制技术提供理论指导。