钢渣对阴离子染料刚果红的吸附特性和机理

Adsorption Properties and Mechanism of Anionic Congo Red Dyeing Wastewater by Steel Slag

研究了钢渣对阴离子染料刚果红的吸附,并考察了初始刚果红浓度、钢渣投加量、钢渣粒径等因素对吸附过程的影响.试验条件下,钢渣可以吸附去除95%以上的刚果红,且吸附过程不受pH值和温度的影响.钢渣单位吸附量随初始刚果红浓度的增加而增加,随钢渣投加量、钢渣粒径的增大而减少.钢渣吸附处理刚果红过程符合准二级吸附速率方程及Freundlich等温吸附方程.对比试验发现钢渣对阳离子孔雀石绿染料的吸附效果优于阴离子刚果红染料,但对同为阳离子染料的亚甲基蓝吸附效果却很差.电镜扫描(SEM)及红外光谱(FTIR)分析进一步表明,钢渣吸附处理阴、阳离子染料的效果,与染料在钢渣表面的结合方式密切相关,结晶体的形成有利于染料分子的吸附.

The adsorption of Congo red from solution was conducted by using steel slag as the adsorbent.The effects of initial concentrations of Congo red,slag dosages and its particle sizes on the adsorption process were investigated.Under the tested condition,steel slag was observed to adsorb above 95% Congo red,and the adsorption process was not affected by pH and temperature.The amount of dye adsorbed per unit weight of steel slag increased with increasing initial concentrations of Congo red,while decreased slightly with the increase of slag dosages and particle sizes.Kinetic and isotherm studies showed that the adsorption process followed the pseudo-second-order kinetic model and Freundlich model respectively.Compared to the adsorption of cationic dye onto slag,the adsorption amount of slag followed the sequence of Malachite Green（cationic dye）〉Congo red（anionic dye）〉Methylene（cationic dye）.Analysis results from Fourier transform infrared spectroscopy（FTIR） and scanning electron microscope（SEM） reveal that the adsorption processes are correlated with the combination ways of dyes onto slag surface,depending on the formation of crystal.