毕业设计幻灯片.ppt

,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,无忧,PPT,整理发布,氨氮在砂土中的吸附,/,解吸动力学研究,研究背景,目的意义,实验研究,论文结论,1.,研究背景,研究表明，铵态氮的环境行为中，吸附作用是一个可以阻滞和延缓氮素进一步迁移和转化，在一定程度上抑制氮素流失的重要过程。,NH,4,+,有机氮溶解在土中,主要存在形式,一部分被植物吸收，另一部分被土吸附,吸附作用,“三氮”,衡量水质的重要指标,2.,目的意义,研究岩土对氨氮的吸附,/,解吸的规律，探讨其吸附,/,解吸的模型,着重考虑“三氮”中氨氮在砂土介质中的吸附,/,解吸的动力学过程，是进行围岩介质与地热水中“三氮”迁移机理研究的基础性工作之一。是理论基础的奠定阶段，对于以后的进一步研究和分析具有重要的意义,目的,意义,3.,实验研究,3.1,研究现状,3.2,土样基本性质,3.3,实验方法,3.4,实验过程,3.5,实验分析,3.1,研究现状,氨氮的吸附和解吸基本都符合一级反应动力学方程,氨氮的吸附,/,解吸速率先增大,而后逐渐变缓。不同粒径的土壤对氨氮的吸附平衡时间几乎相同，但是吸附量不同,可以说土壤粒度的大小只影响土壤吸附和解吸速率，而对吸附和解吸平衡时间影响不大,国外学者采用多种动力学方程对土的反应动力学数据进行拟合,探讨方程的适应性,不同方程的适宜程度不同,土壤化学反应中一些动力学方程只是在一定时间范围内显示具有较好的适应性,国内,国外,3.2,土样基本性质,土样背景氨氮测量,编号,1,2,3,4,5,质量（,g,）,20.003,20.0037,20.0026,20.0033,20.0078,振荡时间（,h,）,0.5,1,2,3,4,离心后吸光度,0.038,0.047,0.045,0.047,0.041,浓度（,mg/L,）,1.1891,2.5103,2.2167,2.5103,1.6295,2mol/L,氯化钾,进一步计算可得，土样中氨氮的含量为,0.0125mg/g,纳氏试剂比色法,3.2,土样基本性质,粒径,/m,5m,5-75m,75-2000m,2000m-60mm,含量,/%,13.2%,22.24%,64.56%,0%,粒径分析一览表,土样粒径分析,3.2,土样基本性质,粒径,/m,200,卵石（碎石）,60d200,粗粒,砾粒,粗砾,20d60,中砾,5d20,细砾,2d5,砂粒,粗砂,0.5d2,中砂,0.25d0.5,细砂,0.075d0.25,细粒,粉粒,0.005d0.075,粘粒,d0.005,土的工程分类标准,（,GB/T50145-2007,）土的粒组划分,3.2,土样基本性质,粒径,/m,5m,5-75m,75-2000m,2000m-60mm,含量,/%,13.2%,22.24%,64.56%,0%,土类,粒组含量,土类代号,土类名称,砂,细粒含量,5%,级配,Cu5,，,1Cc3,SW,级配良好砂,级配：不同时满足上述要求,SP,级配不良砂,含细粒土砂,5%,细粒含量,15%,SF,含细粒土砂,细粒土质砂,15%,细粒含量,0.95,常温下吸附实验,ExpAssoc,模型,y=y,0,+A,1,(1-exp(-x/t,1,)+A,2,(1-exp(-x/t,2,),筛孔数,2mm,0.9mm,0.15mm,震荡时间,min,吸附量,mg/g,吸附量,mg/g,吸附量,mg/g,0,0,0,0,1,0.2943,0.2579,0.284,3,0.2893,0.2811,0.3072,5,0.3049,0.3123,0.3126,15,0.3161,0.2958,0.2893,30,0.3135,0.3151,0.3126,60,0.3151,0.3085,0.2839,120,0.3124,0.3148,0.2827,数据拟合,常温下吸附实验,拟合结果为,R,2,=0.99288,过,2.0mm,筛：,q=2.6286,10,-19,+0.02842,(1-exp(-t/6.15219),+0.28622,(1-exp(-t/0.00187),过,0.9mm,筛：,q=8.1063,10,-19,+0.08552,(1-exp(-t/2.10738),+0.2241,(1-exp(-t/0.00534),过,0.15mm,筛：,q=2.4543,10,-18,+0.04783,(1-exp(-t/0.02612),+0.24822,(1-exp(-t/0.00616),ExpAssoc,模型,y=y,0,+A,1,(1-exp(-x/t,1,)+A,2,(1-exp(-x/t,2,),常温下吸附实验,过,2mm,筛土样,0.31464mg/g,62.93%,过,0.9mm,筛土样,0.30962 mg/g,61.92%,过,0.15mm,筛土样,0.29605mg/g,59.21%,吸附量,吸附率,还有,40%,左右的,氨氮会流失，,对地下水造成,潜在的污染,吸附量差别不大，随粒度增加吸附量略有增加,不同温度下吸附实验,ExpAssoc,模型,y=y,0,+A,1,(1-exp(-x/t,1,)+A,2,(1-exp(-x/t,2,),常温（,20.7,）,40,60,震荡时间,min,土样吸附量,mg/g,土样吸附量,mg/g,土样吸附量,mg/g,0,0,0,0,1,0.2943,0.3016,0.3029,3,0.2893,0.2959,0.2794,5,0.3049,0.2918,0.2655,15,0.3161,0.2922,0.2571,30,0.3135,0.2963,0.257,60,0.3151,0.281,0.2598,120,0.3124,0.2796,0.2932,180,-,0.2753,0.2585,数据拟合,不同温度下吸附实验,常温条件下：,q=-1.06510,-18,+0.02842(1-exp(-t/6.15219),+0.28622(1-exp(-t/0.00187),40,条件下：,q=-9.627210,-20,-0.02543(1-exp(-t/84.58608),+0.29783(1-exp(-t/0.00693),60,条件下：,q=9.431110,-16,-0.06772(1-exp(-t/1.76574),+0.33254(1-exp(-t/0.00086),ExpAssoc,模型,y=y,0,+A,1,(1-exp(-x/t,1,)+A,2,(1-exp(-x/t,2,),拟合结果为,R,2,=,0.99472,不同温度下吸附实验,常温条件下,0.3146mg/g,62.93%,40,条件下,0.2796 mg/g,55.92%,40,条件下,0.2648 mg/g,52.96%,吸附量,吸附率,温度越小,吸附量,越大,常温解吸实验,ExpAssoc,模型,y=y,0,+A,1,(1-exp(-x/t,1,)+A,2,(1-exp(-x/t,2,),振荡时间,h,解吸量,mg/g,解吸量,mg/g,0,0,0,0.25,0.0448,0.0286,0.5,0.056,0.0348,1,0.0535,0.0385,2,0.0585,0.0398,3,0.0784,0.0373,5,0.0768,0.0373,7,0.0784,0.051,24,0.0697,0.0598,数据拟合,常温解吸实验,过,20,目筛土样解吸方程：,q=-0.00002+0.0313,(1-exp(-t/1.72807)+0.04389,(1-exp(-t/0.0902),过,100,目筛土样解吸方程：,q=-1.273810,-9,+0.03189(1-exp(-t/11.52868)+0.03205(1-exp(-t/4.118410,-11,),ExpAssoc,模型,y=y,0,+A,1,(1-exp(-x/t,1,)+A,2,(1-exp(-x/t,2,),拟合结果为,R,2,=,0.95396,常温解吸实验,过,20,目筛土样,0.07517 mg/g,24.28%,过,100,目筛土样,0.05996mg/g,20.25%,解吸量,解吸率,经过较大孔径筛的土样解吸率大,（,1,）该类型粉土质砂对氨氮的吸附、解吸速率均,为先增大，而后逐渐变得缓和，最后达到一个平衡的吸附,/,解吸量。,（,2,）该土在,10min,左右时吸附量即已经达到平衡时的吸附量。而解吸却在,5h,左右才达到平衡解吸量，这充分说明了一旦氨氮的水溶液与土样接触，会马上被土所吸附；而解吸过程却进行的十分缓慢。,4.,论文结论,（,3,）土的粒度的大小对吸附,/,解吸平衡时间的影响不大，而对吸附,/,解吸率却有一定的影响。随粒度增加，吸附解吸率增加。,（,4,）温度对吸附平衡量的影响较大，温度越低，吸附量越大,.,常温条件下：,q=-1.06510,-18,+0.02842(1-exp(-t/6.15219),+0.28622(1-exp(-t/0.00187),40,条件下：,q=-9.627210,-20,-0.02543(1-exp(-t/84.58608),+0.29783(1-exp(-t/0.00693),60,条件下：,q=9.431110,-16,-0.06772(1-exp(-t/1.76574),+0.33254(1-exp(-t/0.00086),经过一定的变形，动力学吸附的方程为：,常温条件下：,ln,（,0.31464-q,）,=ln0.02842-t/6.15219,40,条件下：,ln,（,0.32326-q,）,=ln0.02543-t/84.58608,60,条件下：,ln,（,0.40026-q,）,=ln0.06772-t/1.76574,可以看出，该方程是经过一定变化的一级反应动力学方程。说明，实验用土的氨氮的吸附符合一级反应模型。,经过一定的变形，动力学解吸的方程为：,过,20,目筛土样：,ln,（,0.0752-q,）,=ln0.0313-t/1.7281,过,100,目筛土样：,ln,（,0.0640-q,）,=ln0.0319-t/11.5287,可以看出，该方程是经过一定变化的一级反应动力学方程，说明，实验用土氨氮的解吸符合一级反应模型,（,5,）实验用土的吸附,/,解吸动力学均符合,一级反应动力学模型。,欢迎各位评委老师提出指导,谢谢！,