泡沫掺量对泡沫混凝土孔结构及铅离子吸附性的影响

以P·O42.5硅酸盐水泥为主要原材料,采用压缩空气发泡方式制备了泡沫混凝土,通过立体显微镜观察并表征不同泡沫掺量下泡沫混凝土孔结构,基于不同孔结构研究了泡沫混凝土对Pb2+的吸附作用.研究结果表明,当泡沫掺量为3.77％～ 5.28％时,随泡沫掺量增加气孔的圆度逐渐增大,平均弦长和气孔间距系数均随泡沫掺量增加而逐渐增大,小于0.2 mm的孔含量逐渐减少,0.2～2 mm的孔含量增加,2～4 mm的孔含量显著增加.泡沫混凝土对Pb2+的吸附在动力学上符合准二级动力学模型,等温吸附符合Langmuir吸附等温式,以化学吸附为主.泡沫混凝土对Pb2+的吸附容量高,吸附速率较快,可广泛应用于含Pb2+废水的处理.

Effect of Foam Content on Foamed Concrete Pore Structure and Pb2+ Adsorption

The foamed concrete was prepared by using compressed air foaming method with P · O 42.5 Portland cement as the main raw material.The foamed concrete pore structure under different foam content was observed and characterized by stereomicroscope.The adsorption of Pb2+ on foamed concrete was studied based on different pore structures.The results show that when the amount of foam is 3.77％ -5.28％,the roundness increases with the increase of foam content,the average chord length and the pore spacing coefficient increase with the increase of the foam content,the pore content of less than 0.2 mm is gradually reduced,the pore content of 0.2 mm to 2 mm is increased,and the pore content of 2 mm to 4 mm is significantly increased.The adsorption of Pb2+ on foamed concrete is in accordance with the Pseudo-first-order kinetic model,isothermal adsorption conforms to Langmuir adsorption isotherm,adsorbed Pb2+ via chemical adsorption.The adsorption capacity of Pb2+ in foam concrete is high,the adsorption rate is fast.It can be widely used in the adsorption of Pb2+.