【作者】 李力；

【导师】 涂志英； 易行国；

【作者基本信息】 三峡大学 ， 生态学， 2023， 硕士

【摘要】 草甘膦是目前全球使用最广泛的农药除草剂之一,但每生产1吨草甘膦,就会产生约4.5吨废水,环境处理费用约800-1500元/吨。该废水中包含有部分可再生资源,如草甘膦（1.2-1.8%,w%）和增甘磷（3.0-5.0%,w%）等。如果能对这些废水中高附加值资源进行回收利用,不仅能一定程度降低现有环境处理成本,还能带来二次经济价值。因此,从环境和经济角度考虑,对草甘膦生产废水进行绿色经济的处理,回收其中的高值品,降低环境污染风险具有重要意义。本论文以两种草甘膦生产废水作为研究对象,利用络合氧化策略从草甘膦废水中选择性制备甘氨酸,运用改性树脂吸附技术从草甘膦废水中回收草甘膦,采用次氯酸钠氧化工艺对草甘膦废水进行脱氮回用,实现对该废水的资源化回收利用,为草甘膦生产废水资源化工艺提供了一种新的思路。主要研究内容及结论如下:（1）草甘膦废水组成分析及转化试剂筛选。膜处理蒸发浓缩液（2号废水）总氮（TN）约为2.96×10⁶ mg/L、总磷（TP）约为35323 mg/L、化学需氧量（COD）约为163621 mg/L,P和Cl元素含量分别为6.88%和0.12%;蒸发冷凝水（4号废水）TN约为1100 mg/L。筛选到Fe²⁺/H₂O₂体系从2号废水中转化制备甘氨酸效果最好;Fe³⁺-D301树脂对2号废水中草甘膦的吸附效果最好;Na Cl O氧化体系对4号废水总氮去除效果最好。（2）采用先络合后氧化技术,实现了2号废水选择性转化甘氨酸。重点研究了试剂配比、稀释倍数、温度和p H对甘氨酸转化率的影响,结果表明,最佳反应温度为45℃、最佳试剂配比为1:6、最佳稀释倍数为200～500倍、最佳反应p H为7～8。紫外可见吸收光谱和傅里叶变换红外光谱表明亚铁离子先与草甘膦羧酸基团上的氢氧键发生了络合,再在双氧水条件下发生选择性断键得到甘氨酸。（3）采用Fe³⁺-D301树脂从2号废水中回收草甘膦,利用扫描电子显微镜分析仪（SEM）、SEM配置的能谱仪（EDS）和x射线光电子能谱（XPS）等方式对树脂进行了表征,结果表明,D301树脂上的N原子与Fe原子形成了Fe-N配位键,从而使Fe³⁺负载在D301树脂的上。Fe³⁺-D301树脂对草甘膦的吸附等温线和动力学曲线分别符合Langmuir模型和pseudo-second-order模型,理论最大吸附量q_max=684.6 mg/g。XPS分析表明,Fe³⁺-D301树脂上的Fe与草甘膦分子中P-O键上的O原子配位形成Fe-O-P从而吸附草甘膦。实际废水吸附实验表明,Fe³⁺-D301用量为6.00 g时,对500.00 m L 2号废水中草甘膦的最大吸附率为74.65%。同时Na OH、H₂SO₄和Fe₂（SO₄）₃均可作为解吸剂,草甘膦的解吸率都达到了95.83%以上。（4）采用次氯酸钠氧化法对4号废水进行除氮处理,重点考察了反应温度、p H、反应间隔和加药方式对废水中TN去除的影响,结果表明,在80℃、反应间隔为20min（分六次加入）,加药比例为1:3（前三次:后三次）时,TN去除率最高可达99.45%（TN<40 mg/L）,同时有效含氯量（x）和总氮去除量（y）之间存在良好的相关性（y=0.02033x+166.99646;R²=0.85995）。铜绿微囊藻急性毒性实验表明经蒸汽机械再蒸发技术（MVR）处理后的蒸发冷凝液具有良好的可生化性。最后进行了放大实验,并据此设计了草甘膦生产废水除氮工艺装置。更多还原

【Abstract】 Glyphosate is currently one of the most widely used pesticide herbicides in the world,but for every ton of glyphosate produced,about 4.5 tons of wastewater will be generated,and the environmental treatment cost is about 800-1500 yuan/ton.The wastewater contains some renewable resources,such as glyphosate（1.2-1.8%,w%）and glyphosate（3.0-5.0%,w%）.If these high value-added resources in wastewater can be recycled,it can not only reduce the existing environmental treatment cost to a certain extent,but also bring secondary economic value.Therefore,from the perspective of environment and economy,it is of great significance to treat glyphosate production wastewater in a green and economic way,recover high-value products in it,and reduce the risk of environmental pollution.In this paper,glyphosate production wastewater as the research object,using complex oxidation strategy to selectively prepare glycine from glyphosate production wastewater,using modified resin adsorption technology to recover glyphosate from glyphosate production wastewater,using sodium hypochlorite oxidation process to denitrification and reuse of glyphosate production wastewater,to achieve resource recovery and utilization of this wastewater.It provides a new way to recycle the waste water from glyphosate production.The research content and conclusions are as follows:（1）Composition analysis of glyphosate wastewater and screening of conversion reagents.The total nitrogen（TN）,total phosphorus（TP）and chemical oxygen demand（COD）of the membrane treated evaporation concentrate（No.2 wastewater）were about 2.96×10⁶ mg/L,35323 mg/L,163621 mg/L,6.88%and 0.12%,respectively.The TN of evaporative condensate（No.4 wastewater）is about 1100 mg/L.It was screened that the Fe²⁺/H₂O₂ system had the best effect on the preparation of glycine from No.2 wastewater.Fe³⁺-D301 resin has the best adsorption effect on glyphosate in No.2 wastewater.The Na Cl O oxidation system had the best effect on removing total nitrogen from No.4 wastewater.（2）The selective conversion of glycine from No.2 wastewater was achieved by complexation followed by oxidation.The effects of reagent ratio,dilution ratio,temperature and p H on glycine conversion were studied.The results showed that the best reaction temperature was 45℃,the best reagent ratio was 1:6,the best dilution ratio was 200～500 times,and the best reaction p H was 7～8.Uv-vis absorption spectrum and Fourier transform infrared spectrum showed that ferrous ion complexed with the hydrogen oxygen bond of glyphosate carboxylic acid group first,and then selectively broke the bond under the condition of hydrogen peroxide to obtain glycine.（3）Glyphosate was recovered from No.2 wastewater by Fe³⁺-D301 resin.The resin was characterized by scanning electron microscopy（SEM）,SEM equipped energy spectrometry（EDS）and X-ray photoelectron spectroscopy（XPS）.The results showed that the N atom on D301 resin formed Fe-N coordination bond with Fe atom.Thus,Fe³⁺is loaded on D301 resin.The adsorption isotherms and kinetic curves of Fe³⁺-D301 resin for glyphosate were consistent with Langmuir model and pseudo-second-order model,respectively,and the theoretical maximum adsorption capacity qmax=684.6 mg/g.XPS analysis showed that Fe on Fe³⁺-D301resin coordinated with the O atom on the P-O bond in glyphosate molecule to form Fe-O-P and adsorb glyphosate.The actual wastewater adsorption experiment showed that the maximum adsorption rate of glyphosate in 500.00 m L of No.2 wastewater was 74.65%when the dosage of Fe³⁺-D301 was 6.00 g.At the same time,Na OH,H₂SO₄ and Fe₂（SO₄）₃ could all be used as desorption agents,and the desorption rate of glyphosate reached more than 95.83%.（4）The effect of reaction temperature,p H,reaction interval and dosing method on the removal of TN in No.4 wastewater was investigated by sodium hypochlorite oxidation method.The results showed that at 80℃,reaction interval was 20 min（six times added）,dosing ratio was 1:3(the first three times:The highest TN removal rate was 99.45%（TN<40 mg/L）,and a good correlation was found between the amount of sodium hypochlorite（x）and total nitrogen removal（y）（y=0.02033x+166.99646;R²=0.85995）.The acute toxicity test of Microcystina aeruginosa showed that the evaporative condensates treated by steam mechanical re-evaporation（MVR）had good biodegradability.Finally,the amplification experiment was carried out,and the process device for removing nitrogen from glyphosate wastewater was designed.更多还原