【作者】 高叶松；

【导师】 欧阳通；

【作者基本信息】 厦门大学 ， 环境工程， 2008， 硕士

【摘要】 随着有机合成农药的大量使用,在农作物、土壤、水体及大气中的农药残留问题逐渐突出。目前,处理农药废水的技术有很多,如活性炭吸附法、催化氧化法、化学絮凝法、活性污泥法等。本文的研究重点为普通粘土矿物—高岭土和硅藻土的改性技术及其对甲基异柳磷的吸附特性研究。本文采用十六烷基三甲基溴化铵(HDTMA)对高岭土和硅藻土进行改性,并研究其制备条件对甲基异柳磷的吸附性能影响。结果表明,在室温和pH=4的条件下用0.6 CEC当量的HDTMA反应15 min改性制备的有机高岭土对甲基异柳磷的吸附效果最佳;而有机硅藻土的最宜制备条件为:室温,pH为7,HDTMA:CEC为0.5,反应时间为15 min。在静态条件下,研究了甲基异柳磷初始浓度、吸附时间、溶液pH值、吸附剂投加量及盐的加入等因素对吸附效果的影响,求得了有机高岭土和硅藻土的静态吸附等温线。实验结果表明,有机高岭土及硅藻土对甲基异柳磷的吸附反应速率较快,在最佳吸附条件下,即有机高岭土投加量为10 g/L,溶液中甲基异柳磷的初始浓度为30 mg/L,吸附平衡时间为40 min,在所选pH(5-9)范围内甲基异柳磷的去除率均能保持在80%左右;在所实验的pH范围内(4-10),室温、吸附时间20 min、吸附剂投加量10 g/L,有机硅藻土对初始浓度为30 mg/L的甲基异柳磷的吸附率可保持在34.0%左右。溶液中某些共存离子可以明显提高有机高岭土和硅藻土的吸附性能。有机高岭土和硅藻土对甲基异柳磷的吸附行为可较好地采用Freundlich吸附等温式进行描述。采用动态吸附实验求得了有机高岭土和有机硅藻土对甲基异柳磷的吸附穿透曲线,同时研究了有机粘土与土壤的质量比及溶液pH值等因素对吸附效果的影响。在到达穿透点前,40 g土壤与80 g有机高岭土对甲基异柳磷的吸附率可高达94.1%,而30 g土壤与30 g有机硅藻土对甲基异柳磷的最高吸附率为66.6%。随着吸附层中有机硅藻土所占比例的增加,甲基异柳磷的去除率呈现增大的趋势。当其它条件一定时,进水溶液pH值对甲基异柳磷的去除率影响很小。更多还原

【Abstract】 With the vast use of organic man-made pesticide,the pollution of the remnant gradually goes serious.Various techniques have been used to remove pesticide from waste water,including active carbon adsorption,catalyse oxidation,chemical coagulation and activated sludge process.This paper emphasizes the modification techniques of common clay minerals—kaolin and diatomite and the adsorption to the isofenphos-methyl.In this paper,Hexadecyltrimethylammonium(HDTMA) was used to modify kaolin and diatomite.The influence of synthetic conditions on the isofenphos-methyl adsorption of modified clays was investigated.The experimental results indicated that the organic kaolin prepared at room temperature,pH of 4,dosage of HDTMA at the proportion of 0.6 CEC and react time of 15 minutes showed the best adsorption performance,while the appropriate condition to make organic diatomite was:room temperature,the pH value was 7,the dosage of HDTMA was 0.5CEC,the react time was 15 minutes.The properties and optimal conditions for organic clays to adsorb isofenphos-methyl were investigated under static state in the laboratory and also the effects of the initial concentration,adsorption time,adsorbent concentration,the pH value and salt were discussed.Through the test,made the static adsorption isotherms of organic kaolin and diatomite,the research results indicated that the adsorption rate of isofenphos-methyl with the two kinds of sorbent was rapid.About 80%removal of isofenphos-methyl could be achieved within 40 minutes at the initial concentration of 30 mg/L,dosage of modified kaolin at 10 g/L in the natural water pH range of 5 to 9, while the removal rate by organic diatomite could reach to 34.0%within 20 minutes at room temperature,initial concentration of 30 mg/L,adsorbent concentration of 10 g/L in the pH range of 4-10.Besides,the addition of salt could obviously improve the adsorption capability of organic kaolin and diatomite.The adsorption isotherms of isofenphos-methyl with the two kinds of sorbent all fitted the Freundlich equation.Through the dynamic adsorption,made the penetrating curves of organic kaolin and diatomite,also has conducted the experimental study to the influence factors, such as the mass ratio of organic clays and soil and the pH value.The results showed that the optimal removal rate of isofenphos-methyl by 40 g soil and 80 g organic kaolin might reach to 94.1%,however,that of 30 g soil and 30 g organic diatomite was only 66.6%.The removal effect was improved with increase in proportion of organic diatomite in adsorption layer.Furthermore,the pH value played a trifling role to the adsorption effect.更多还原