【作者】 陶志颖；

【导师】 许仕荣；

【作者基本信息】 湖南大学 ， 市政工程， 2010， 硕士

【摘要】 随着水污染的日益严重和饮用水水质标准的不断提高,传统的净水工艺已难以满足居民生活用水水质标准,活性炭滤池作为深度处理工艺单元得到了广泛应用和深入研究。一般认为,活性炭滤池出水残余铝浓度平均降低50%,但实际生产过程中却发现个别活性炭滤池经长期运行后,其出水残余铝浓度明显高于沉后水,且pH值升高会加速该情况出现。鉴于活性炭滤池这种特殊性,本文结合净水工艺中铝的浓度变化和影响因素,通过试验对活性炭吸附与解吸铝进行了较为深入的研究。首先,通过对净水工艺中铝的浓度变化调查及影响因素分析：水厂原水铝浓度较低；沉后水残余铝浓度可能高于原水；砂滤出水残余铝浓度低于沉后水；运行正常的活性炭滤池在进水pH升高后出水残余铝浓度高于砂滤水,初步认为水厂各工艺单元出水残余铝浓度变化主要原因为：碱铝混凝剂的投加和石灰水的投加而引起的pH值升高。其次,基于吸附基本机理,考虑改变吸附条件(初始铝浓度、吸附剂投加量、温度、吸附时间和pH值)对新炭吸附铝进行试验,结果表明：吸附剂投量过多会导致高投加量对应低吸附容量；初始铝浓度过高会导致高初始浓度对应低吸附率；吸附效果随温度升高而提高；吸附过程分前期、中后期两个阶段；吸附平衡后,无论怎样延长吸附时间,相同条件下吸附速率不变；碱性和酸性吸附效果都较好,中性吸附效果最差,控制pH值在中性左右可以延长活性炭使用周期,减少活性炭因铝的吸附饱和而需再生的次数。最后,基于解吸基本机理,考虑改变解吸条件(温度、解吸时间、pH值、解吸剂种类和解吸剂浓度)进行了吸附平衡后的活性炭对铝的解吸试验,结果表明：解吸效果随温度升高而提高；解吸过程分初期、中期和后期三个阶段；解吸平衡后,无论怎样延长解吸时间,相同条件下解吸速率不变；碱性和酸性解吸效果都较好,中性解吸效果最差,控制pH值在中性左右可以延缓活性炭滤池炭解吸铝速率；活性炭滤池出水铝超标,对其进行再生,解吸剂NaOH的最佳浓度为0.20mol/L。此试验结果对于控制炭池出水残余铝浓度具有重要参考价值。更多还原

【Abstract】 With the increasing standards of water purity and increasing water pollutions,the traditional purification process of water is difficult to meet the drinking standard of living.As an advanced water treatment unit,active carbon basin is studied deeply and is used in water purification process.Generally speaking,the average aluminum concentration of water has decreased by 50% after filtering in the carbon basin. Actually,the aluminum concentration of water from the carbon basin is obviously higher than sedimentation from original water,which occurs in some individual tank after running long-time.And the increasing of pH value will activate this process. With the special characteristic of active carbon basin,the experimental study is performed for absorption and desorption of aluminum using active carbon with considering the influencing factor for aluminum concentration in process of water purification in this article.Firstly,according to the survey and the experiment research of the influencing factor in the water purification process,the conclusion is that the concentration of aluminum is impacted by pH value and the dosage of coagulant and coagulant-aids.Secondly,based on absorption theory,the absorption corresponding experiment is performed according to different initial aluminum concentration,the dosage of adsorbent,temperature,time and pH value.The experiment result shows that high dosage of absorbent and high initial aluminum concentration results in low absorption capacity;the adsorption effect elevates along with the temperature enhance.The adsorption process divides into two periods:earlier,mid and late;after adsorption equilibrium,the rate of adsorption keeps same regardless of lengthening the adsorption time under same condition.pH value is an important carbon absorption efficiency factor of aluminum; the neutral condition adsorption effect is worst.Finally,based on desorption theory, the desorption corresponding experiment is performed according to concentration of desorbing,the category of desorbing, desorbing temperature,time and pH value after the adsorption equilibrium.The conclusion is that the increasing desorbing effect with increasing temperature;the desorption process is divided into three period:initial,medium-term,and late.When being balance,no matter how to extend the time of desorbing, the rate of desorption will not change;pH value is the main factor in the process of carbon desorbing aluminum.The effect of desorption is better with acidic and alkaline but the neutral condition is worst;The effect of five kind of strippants(NaAC,NaHCO3,Na2CO3, Na3PO4,NaOH),NaOH are the best for the activated charcoal desorption aluminum;in six density of NaOH(0.01mol/L,0.05mol/L,0.10mol/L,0.20mol/L,0.50mol/L, 1.0mol/L),the effect of 0.20mol/LNaOH is best for the activated charcoal desorption aluminum.The experiment results will have great value on controlling the aluminum concentration of water from the active carbon basin.更多还原