稻床养鸡固废中残留抗生素和砷的微波处理研究

发布时间：2018-08-14 18:52

【摘要】：随着经济和物质水平快速发展,鸡肉的需求量逐渐增大。越来越多的规模化集约养鸡场随之出现,并带来了数量巨大的鸡粪,亟待处理。四环素类抗生素(TCs)和洛克沙胂(ROX)是养鸡过程中极为常用的两类药剂,在鸡粪中通常有较多的残留。目前大量的鸡粪常采用传统的堆肥技术处理为有机肥,但其中残留的TCs通常难以降解,而有机砷在堆肥过程中容易转化为毒性更大的无机砷,存在更大的环境风险。而微波催化热解技术不仅能有效降解有机污染物,也能稳定固化重金属。本研究以集约养鸡业产生的稻壳鸡粪(Rice Husk Chicken Manure,RHCM)为处理对象,分别开展其中残留TCs的微波热解技术和残留砷的药剂稳化/微波固定联用技术的系统研究,对微波处理系统的作用机理进行了探讨,并对稻壳鸡粪微波制备生物炭的可行性和经济性进行了分析和评估。主要研究结论包括:(1)在稻壳鸡粪中TCs的微波热降解实验研究中,对药剂种类、微波功率、辐照时间等实验条件对TCs降解的影响进行了探讨,从结果可知:碳化硅材质容器显示出优越的微波吸收能力而被选为微波热降解稻壳鸡粪中TCs的反应容器,Fe SO4·7H2O的加入被证明能够显著提升稻床养鸡固废的微波吸收性能,当Fe SO4·7H2O固体掺杂量达到10%(m/m)的质量比例,在优化实验微波条件:560W、20min下,两种TCs的消减率均高于95%。高效液相色谱(HPLC)对降解产物的分析鉴定了TCs在热解过程中先发生差向异构化、脱水分解反应,最后母体及产物完全矿化的降解过程。中试微波热解处理稻壳鸡粪中TCs的效果可以满足项目要求。(2)在稻壳鸡粪中砷(As)的稳定化实验研究中,Fe SO4·7H2O展示了比碱性物质、钙盐、硫化物更强的对砷的稳定/固定化作用。而微波高温固定化技术与药剂稳定化技术被本研究证明对As的无害化处理具有协同作用,其中Fe SO4·7H2O同时起到了共沉淀稳定剂和微波敏化剂的关键性作用。在5%(m/m)比例的Fe SO4·7H2O添加量,700W、20min的优化微波条件组合下,稻壳鸡粪中砷的稳定/固化率达到了96.1%。微波中试研究验证了此联用技术对批量稻床养鸡固废砷处理的可行性。对洛克沙胂的热重分析结果阐明了其在微波热解过程中先迅速降解为无机砷而后被铁离子稳定及被微波高温固定。对处理后RHCM的XPS表征揭示了Fe元素主要以Fe2O3和Fe3O4形式存在,而其中As则形成了稳定的Fe As O3。(3)对制备产物—稻壳鸡粪生物炭进行BET、SEM、FTIR等吸附特性、表面形貌和理化性质的表征和分析,结果表明本研究微波热解产物为介孔物质,可见发达孔隙结构和大量灰分,颗粒尺寸主要集中在10-100μm。碳材料表面官能团种类丰富,饱含氮磷等营养元素,且重金属含量远低于标准,微生物指标同样符合农田利用标准。因此所制备生物炭在土壤改良及土壤修复领域显示出良好的市场前景。在研究基础上完成了连续化的微波鸡粪处理设备的初步设计。
[Abstract]:With the rapid development of economy and material level, the demand for chicken is increasing gradually. More and more intensive chicken farms appear, and bring a huge amount of chicken manure, which needs to be dealt with. Tetracycline antibiotics (TCs) and roxarsone (ROX) are two kinds of fungicides commonly used in chicken breeding. At present, a large amount of chicken manure is usually treated as organic manure by traditional composting technology, but the residual TCs is usually difficult to degrade, while organic arsenic is easily converted into inorganic arsenic with greater toxicity during composting, and there is a greater environmental risk. Microwave catalytic pyrolysis can not only effectively degrade organic pollutants, but also stabilize the solidification of heavy metals. In this study, rice husk chicken dung (Rice Husk Chicken manureus) produced from intensive chicken industry was treated with microwave pyrolysis technique of residual TCs and combined technique of stabilization and microwave fixation of residual arsenic. The mechanism of microwave treatment system was discussed, and the feasibility and economy of microwave preparation of biochar from rice husk chicken manure were analyzed and evaluated. The main conclusions are as follows: (1) in the experimental study of microwave thermal degradation of TCs in rice husk chicken manure, the effects of the kinds of medicament, microwave power and irradiation time on the degradation of TCs were discussed. The results showed that the silicon carbide material container showed superior microwave absorption ability and was selected as the reaction container for microwave thermal degradation of TCs in rice husk chicken dung. It was proved that the addition of Fe SO4 7H2O could significantly improve the microwave absorption performance of rice bed chicken solid waste. When the mass ratio of Fe SO4 7H2O solid doping is 10% (m / m), the reduction rate of both TCs is higher than 95% under the optimized microwave condition: 560W / min. Analysis of degradation products by (HPLC) the degradation process of TCs in pyrolysis was characterized by differential isomerization dehydration and decomposition finally the parent and product were completely mineralized. The effect of microwave pyrolysis on the treatment of TCs in rice husk chicken dung could meet the requirements of the project. (2) in the stabilization experiment of arsenic (As) in rice husk chicken dung, Fe SO4 7H2O showed more stable / immobilized arsenic than alkaline substances, calcium salts and sulfides. The technology of microwave immobilization at high temperature and the technology of medicament stabilization have been proved to be synergistic to the innocuous treatment of as, among which Fe SO4 7H2O plays the key role of both coprecipitation stabilizer and microwave sensitizer. Under the optimized microwave condition of adding Fe SO4 7H2O to 5% (m / m) of rice husk chicken manure for 20 min, the stabilization / solidification rate of arsenic reached 96.1%. The microwave pilot study verified the feasibility of the combined technology for the treatment of solid arsenic in batch rice bed chicken. The results of thermogravimetric analysis of roxarsone show that it is rapidly degraded to inorganic arsenic and then stabilized by iron ion and fixed by microwave during microwave pyrolysis. The XPS characterization of treated RHCM revealed that Fe existed mainly in the form of Fe2O3 and Fe3O4, and that as formed a stable Fe as O 3. (3) the preparation product, rice husk chicken manure biochar, was adsorbed by BET-SEMFTIR. The surface morphology and physicochemical properties were characterized and analyzed. The results showed that the microwave pyrolysis product was mesoporous material, developed pore structure and a large amount of ash, and the particle size was mainly concentrated in 10-100 渭 m. The surface functional groups of carbon materials are rich in kinds of nutrient elements such as nitrogen and phosphorus, and the heavy metal content is far below the standard, and the microbial index is also in line with the farmland utilization standard. Therefore, the prepared biochar has a good market prospect in the field of soil improvement and soil remediation. On the basis of the research, the preliminary design of continuous microwave chicken manure treatment equipment was completed.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X713

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