水中对羟基苯甲酸酯的污染调查及在化学预氧化法中的去除机理研究

发布时间：2018-03-09 00:12

  本文选题：对羟基苯甲酸酯类化合物　切入点：污染调查　出处：《合肥工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：对羟基苯甲酸酯类化合物作为防腐杀菌剂被广泛应用,由于大量使用,现已在地表水、地下水、饮用水、污水、空气、灰尘及土壤等中检测到,尤其在水体环境中污染更严重,对水体环境安全造成了严重的威胁。本文调查了几类水体:湖泊水、河流水、地下水和自来水中对羟基苯甲酸酯类化合物的污染现状,并研究了次氯酸钠和二氧化氯工艺对对羟基苯甲酸酯类化合物的降解动力学、影响去除效果的主要因素和降解机理。调查了几类水体中对羟基苯甲酸酯的污染现状。在湖泊水样中对羟基苯甲酸酯类化合物总量较低,地下水中该类药物浓度较大,介于51.59-77.70 ng/L,其主要来源于生活污水。地表河流中对羟基苯甲酸酯类化合物浓度范围为18.13-42.47ng/L,其主要来源为污水处理厂;在自来水中也检测到了该类药物的存在,表明给水处理厂对其去除效果有限,需探求有效的方法处理对羟基苯甲酸酯类化合物。研究了次氯酸钠对四种对羟基苯甲酸酯的去除效果与机理。在pH=7.0,温度为25±1℃条件下,对羟基苯甲酸甲酯(MeP)、对羟基苯甲酸乙酯(EtP)、对羟基苯甲酸丙酯(PrP)和对羟基苯甲酸丁酯(BuP)与次氯酸钠的反应级数分别为1.614,2.019,1.851和1.860。随着pH值的增加,对羟基苯甲酸酯的反应常数先增加后减小;随着温度的增加,反应常数不断增加;加入NH4+和腐殖酸后,对羟基苯甲酸酯的氯化反应过程受到抑制。对羟基苯甲酸酯与次氯酸钠的反应过程中,溶液的TOC几乎未改变,矿化程度很低,通过GC-MS每种药物分别检测到两种转化产物;加入Br-和I-后,会大大影响转化产物的种类,生成溴代和碘代产物。研究了二氧化氯对两种对羟基苯甲酸酯的去除效果与机理。二氧化氯与MeP和PrP的反应符合二级动力学模型;在pH=5.0,温度为15±1℃条件下,二级反应速率常数分别为84.3 M-1·s-1和83.2 M-1·s-1。随着pH值和温度的增加,对羟基苯甲酸酯的反应常数都会逐渐增大;在反应体系中加入腐殖酸后,二氧化氯与对羟基苯甲酸酯的反应过程受到抑制;加入HCO3-后会在一定程度上促进反应的发生。对羟基苯甲酸酯的去除过程中,TOC几乎未改变,矿化程度很低;通过GC-MS技术,检测到两种降解产物,并根据降解产物推测出可能的降解途径。在自然水体中二氧化氯对微量对羟基苯甲酸酯的去除效果很好,可以达到有效去除该类药物的目的。
[Abstract]:P-hydroxybenzoate compounds are widely used as antiseptic fungicides. Due to their extensive use, they have been detected in surface water, groundwater, drinking water, sewage, air, dust and soil, especially in the water environment. This paper investigates the pollution status of p-hydroxybenzoate compounds in lake water, river water, groundwater and tap water. The degradation kinetics of p-hydroxybenzoate by sodium hypochlorite and chlorine dioxide was studied. The main factors affecting the removal efficiency and the degradation mechanism were investigated. The pollution status of p-hydroxybenzoate in several kinds of water was investigated. The total amount of p-hydroxybenzoate in lake water was lower, and the concentration of this kind of drugs in groundwater was higher. Between 51.59 and 77.70 ng / L, mainly from domestic sewage. The concentration of p-hydroxybenzoate compounds in surface rivers ranges from 18.13-42.47 ng / L, mainly from sewage treatment plants, and the presence of such drugs is also detected in tap water. The results show that the removal efficiency of p-hydroxybenzoate in feed water treatment plant is limited, and an effective method is needed to treat p-hydroxybenzoate compounds. The removal efficiency and mechanism of four p-hydroxybenzoate esters by sodium hypochlorite have been studied. Under the condition of pH = 7.0 and temperature 25 卤1 鈩，

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