摘要
采用简单快速的合成法制备多级孔Zeolitic Imidazole Frameworks-67(ZIF-67)并将其应用到染料废水AO7的吸附处理中。通过SEM、BET、XRD、TG等手段对吸附前后的ZIF-67进行了表征,并对吸附动力学、吸附速率控制步骤及ZIF-67再生特性进行了详细研究。结果表明:合成的ZIF-67尺寸均匀,具有微孔材料的吸附特征;其在400℃仍具有热稳定性且在吸附反应前后晶型和结构基本没有发生变化,表明其具有较强的热稳性和水稳性。ZIF-67对AO7表现出良好的吸附性能,其对初始质量浓度为20 mg/L、50 mg/L、100 mg/L和150 mg/L的AO7的吸附量分别为38.96 mg/g、96.87 mg/g、182.39 mg/g和255.25 mg/g。不同初始质量浓度的AO7在ZIF-67上的吸附均符合伪二级动力学方程(R2> 0.999),伪二级动力学方程拟合的理论吸附量qe,cal与实测平衡吸附量qe,exp的相对误差仅为5.44%~8.66%;吸附反应受颗粒内扩散和吸附反应过程2个步骤控制。溶液p H值是影响ZIF-67吸附AO7效率和材料重复利用性能的重要因素;初始pH=8(接近AO7的p Ka)时,ZIF-67显示出对AO7最强的吸附能力(qe=39.10 mg/g,ρ0=20 mg/L,V0=100 m L,ZIF-67投加量500 mg/L,T=25℃)和较为理想的可再生性(3次循环后吸附量仅降低12.69%)。
The present paper intends to trace and study the high chroma,for it is of strong toxicity and difficult degradative features of the multi-stage porous ZIF-67,which can be synthesized from the cobalt nitrate hexahydrate,the 2-methylimidazole and the triethylamine with a convenient and quick synthesis method by removing the AO7 from the aqueous solution acidic orange 7( short for AO7). And,then,the gained ZIF-67 pre-&-pro adsorption can be said featured by SEM,BET,XRD and TG,whereas it is possible for the adsorption kinetics dynamics,the rate controlling step and the regeneration power of the adsorbent to be traced and investigated in detail. The results of our investigation indicate that the gained ZIF-67 through synthesis turns out to be uniformed in size and adsorptive by the micro-porous materials. The other detailed features can be illustrated as follows: its thermal stability is high at 400 ℃,its crystallized shape and structure pre-&-pro adsorptive reaction can be basically unchanged,thus,signifying that it has strong thermal stability and water solubility. To be more specific,it demonstrates nice adsorptive performance for AO7,with its initial adsorptive mass concentrations being of 20 mg/L,50 mg/L,100 mg/L and 150 mg/L respectively,i. e. at the rates of 38. 96 mg/g,96. 87 mg/g,182. 39 mg/g and 255. 25 mg/g,correspondingly. On the other hand,its adsorption on the ZIF-67 tends to follow a pseudo-second-order equation kinetics model( R2> 0. 999) closely,with the relative error between the theoretical adsorption capacity( qe,cal) calculated by pseudo-second-order equation and the equilibrium adsorption capacity( qe,exp) that can be measured being merely of 5. 44%-8. 66%. What is more,the adsorptive reaction of AO7 on ZIF-67 can all be controlled by the intrapartial diffusion and adsorption reaction process. Besides,the p H value of the solution has been found to be an important factor influencing the adsorption efficiency and material reuse performance of ZIF-67. For instance,when the initial p H value is 8,that is,close to the p Kaof AO7,its strongest adsorption capacity and idealistic regeneration power toward AO7,as well as the equilibrium adsorption capacity( qe) can be so high as to 39. 10 mg/g under the condition of ρ0= 20 mg/L,V0= 100 m L,dosage500 mg/L and T = 25 ℃ with the adsorptive power reduced by merely 12. 69% after 3 recycles.
作者
宋珍霞
蔡长青
赵晓宇
邾文婷
SONG Zhen-xia;CAI Chang-qing;ZHAO Xiao-yu;ZHU Wen-ting(College of Biological and Chemical Engineering,Anhui Polytechnic University,Wuhu 241000,Anhui,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2020年第5期1871-1878,共8页
Journal of Safety and Environment
基金
安徽省高等教育提升计划科学研究项目(TSKJ2016B15)
安徽省大学生创新创业训练计划项目(201810363194)。
