废白土炭去除印染废水过程中多染料竞争吸附的研究

Study on Competitive Adsorption of Multiple Dyes in the Process of Removing Printing and Dyeing Wastewater by Spent Bleaching Earth Carbon

以废白土资源化利用为出发点,将SBE通过缺氧高温煅烧制备成废白土炭(SBE@C)吸附剂,探究多染料竞争吸附的关系。考察不同热解温度对SBE@C吸附印染废水中三种染料(甲基橙、曙红Y和茜素红)的影响,并对热解前后的材料进行SEM、EDAX、BET、XRD、FTIR和XPS表征分析。结果表明,高温热解法使SBE表面残油被炭化,增大了比表面积和孔体积,从而提升了吸附容量;热解温度为800℃时,SBE@C对染料的吸附效能最佳;多元竞争吸附实验表明,三种染料之间均存在一定程度的竞争吸附,且多元污染过程均由化学吸附决定,符合颗粒内扩散模型;用NaOH溶液对SBE@C进行再生,四次循环后SBE@C对三种染料仍具有良好的吸附能力。

Spent bleaching earth(SBE)is a solid waste produced in the process of oil refining.The improper disposal of SBE would cause environmental pollution and waste of resources.Considering the resource utilization of SBE,SBE was anoxically calcined to prepare spent bleaching earth carbon(SBE@C)adsorbent at high temperature,and the study of competitive adsorption of multiple dyes by SBE@C was performed.The effect of different pyrolysis temperatures on the adsorption of three dyes(i.e.,methyl orange,eosin Y,alizarin red)by SBE@C in printing and dyeing wastewater was studied.SEM,EDAX,BET,XRD,FTIR and XPS characterization analysis of the materials before and after pyrolysis were carried out.The results showed that the high temperature pyrolysis carbonized the residual oil on the surface of SBE,which increased the specific surface area and pore volume,thereby increasing the adsorption capacity.When the pyrolysis temperature was 800℃,SBE@C had the best adsorption performance for dyes.Multiple competitive adsorption experiment showed that there was a certain degree of competitive adsorption among the three dyes.Also,the multiple competitive adsorption process was determined by chemisorption,and fitted well with the intra-particle diffusion model.SBE@C was regenerated with NaOH solution,and SBE@C still had a great adsorption performance for the three dyes after four cycles.