氨水改性活性炭的制备及其对苯酚吸附性能的研究

Experimental Study on Preparation and Adsorption Behavior About Phenol of Ammonia Modified Activated Carbon

以活性炭为载体,10%的氨水溶液为改性剂,采用浸渍法对其进行改性.利用比表面积测定法、SEM及Boehm滴定法表征了氨水改性活性炭的表面理化性质.以苯酚废水为处理对象,分别考察了吸附时间、pH值、活性炭投加量及苯酚废水的初始浓度对改性活性炭去除苯酚效果的影响.结果表明:活性炭经氨水改性后,表面多处塌陷,比表面积是未改性活性炭的1.057倍,表面酸性官能团含量降低,是未改性活性炭的0.421倍.在吸附时间为6h时,活性炭对苯酚的吸附均已达到平衡,改性活性炭对苯酚的吸附量为152.763mg/g,比未改性活性炭的吸附量提高了66%;氨水改性活性炭对苯酚的去除率随着pH值升高而降低,在pH值为6～7时,去除率达到61%;随着活性炭投加量的增加,溶液中的苯酚含量越来越少;随着苯酚废水初始浓度的提高,氨水改性活性炭对苯酚的去除率逐渐降低;Freundlich和Langmuir二种等温线模型均能较好的反应活性炭对苯酚的吸附行为,其中Freundlich模型更为理想.

In this experiment activated carbon was chosen as a carrier to be modified by ammonia with the immersion method.Surface property was characterized by area measurement,SEM and Boehm titration.Effect of adsorption time,pH,modified activated carbon dosage and initial concentration of phenol were investigated.The results show that the surface of ammonia modified activated carbon had much collapse,the specific surface area was 1.057 times that of unmodified activated carbon.The amount of total surface acidic functional groups were decreased to 0.421 times that of untreated GAC.Under the condition of adsorption time with 6 hours,the adsorption capacity was balanceable,the adsorption capacity of modified activated carbon was 152.763mg/g and improved 66%.Along with the increase of pH value,the removal rate of phenol was reduced,Under the condition of pH value with 6 to 7,the removal rate of phenol was 61%.With the increase of carbon dosing quantity,the removal rate of phenol also was increased.With the increase of the initial concentration of phenol,the removal of phenol was reduced.Both Freundlich and Langmuir model of sorption isotherms could reflect the adsorption behavior of modified activated carbon for phenol,while the Freundlich model was more properly.