纳米过氧化钙联合污泥裂解液降解土壤中四溴双酚A的研究

发布时间：2018-06-28 13:44

  本文选题：土壤修复 + 四溴双酚A　； 参考：《大连理工大学》2016年硕士论文

【摘要】：四溴双酚A是当前使用最普遍的溴代阻燃剂,研究表明它具有毒性。如果不对其进行妥善的处理,将对人类健康和生态环境产生很大的危害。四溴双酚A微溶于水,它容易在土壤中聚集,对土壤造成严重的污染。当前关于土壤中四溴双酚A的降解报道不是很多,主要的方法有物理化学法和生物法。本文首次采用纳米过氧化钙联合污泥裂解液来修复四溴双酚A污染的土壤,取得了如下的研究成果。首先以无水氯化钙和过氧化氢为原料,加入不同分散剂制备纳米级过氧化钙。分散剂分别采用常规分散剂聚乙二醇1000和经氢氧化钠破解剩余污泥制备产生的污泥裂解液。结果表明,分散剂聚乙二醇1000用于反应时,纳米过氧化钙的产率为68.46%,纯度为65.55%,粒径在100-250 nm之间。污泥裂解液作为分散剂制备的纳米过氧化钙的产率为66.91%,纯度为65.51%,粒径在100-200 nm之间。由此表明污泥裂解液可作为分散剂来制备纳米过氧化钙,具有较好的分散效果。这也为剩余生物污泥的资源化利用提出了一条新的参考路径。此外,本文对不同土壤体系下四溴双酚A的测试方法及条件进行了研究。首先确定了用于测试的土壤样品干燥温度为50℃；对于污染土样、污染土样加水、污染土样加水和纳米过氧化钙的体系,采用氢氧化钠提取法测试时相对误差分别为2.38%、2.08%和17.36%,土壤样品测试的适宜pH值为9.0。对于污染土样加污泥裂解液体系,采用乙酸乙酯法提取四溴双酚A比氢氧化钠法更准确,氢氧化钠提取四溴双酚A时的相对误差是30.94%,而乙酸乙酯提取时相对误差只有6.02%。在明确测试方法及条件的基础上,研究了不同土壤体系下四溴双酚A的降解情况。不同的体系分别是由污泥裂解液,纳米过氧化钙和水组成或是由它们联合组成。研究表明降解土壤中四溴双酚A较好的体系是土壤加裂解液和纳米过氧化钙的体系。在此体系下,纳米过氧化钙用量为0.2g,降解时间为20天时,污染土壤20 g (TBBPA含量50 mg/kg)中TBBPA的降解率达到71.85%。在上述研究的基础上,对土壤中四溴双酚A的降解机理进行了初探。通过对土壤中脱氢酶活性的测定及考察土壤中微生物是否失活对四溴双酚A降解的影响,可推测四溴双酚A的降解主要是通过生物法和化学法联合作用而实现的。通过对LC-MS检测的四溴双酚A降解的产物进行解析,推测在污泥裂解液和纳米过氧化钙的共同作用下,土壤中四溴双酚A的降解路径可能有三种方式：脱溴,p键的断裂和甲基化的反应。
[Abstract]:Tetrabromobisphenol A (BPA) is the most commonly used brominated flame retardant and has been shown to be toxic. If it is not properly handled, it will do great harm to human health and ecological environment. Tetrabromobisphenol A is slightly soluble in water, and it is easy to accumulate in the soil, causing serious pollution to the soil. There are few reports about the degradation of tetrabromobisphenol A in soil. The main methods are physicochemical method and biological method. In this paper, nanometer calcium peroxide combined with sludge pyrolysis solution was used for the first time to repair the soil contaminated by tetrabromobisphenol A (BPA), and the following results were obtained. Firstly, nanometer calcium peroxide was prepared from anhydrous calcium chloride and hydrogen peroxide by adding different dispersants. The sludge pyrolysis liquid was prepared by conventional dispersant polyethylene glycol 1000 and sodium hydroxide cracking sludge. The results show that when the dispersant polyethylene glycol 1000 is used in the reaction, the yield of nano-calcium peroxide is 68.46, the purity is 65.55 and the particle size is between 100-250 nm. The yield of nanometer calcium peroxide prepared by sludge pyrolysis solution as dispersant is 66.91, the purity is 65.51 and the particle size is between 100-200 nm. The results show that sludge cracking liquid can be used as dispersant to prepare nanometer calcium peroxide and has good dispersion effect. It also provides a new reference path for the utilization of surplus biological sludge. In addition, the test methods and conditions of tetrabromobisphenol A in different soil systems were studied. The drying temperature of the soil sample for testing was determined to be 50 鈩，

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