节点文献
稻壳灰吸附剂对罗丹明B的吸附性能研究
Studies on the adsorption of Rhodamine B by rice husk ash adsorbent
【摘要】 以发电废弃物稻壳灰为原料,以NaOH为活化剂制备了稻壳灰吸附剂,并将其用于去除水中罗丹明B(Rhodamine B,Rh B)染料。系统考察了溶液pH值、初始浓度、吸附时间、吸附温度以及溶液离子强度对其吸附性能的影响。结果表明:pH=3时,稻壳灰吸附剂对水中Rh B的吸附效果最佳,饱和吸附容量qm为322. 6mg·g-1;吸附热力学研究表明,吸附过程符合Langmuir等温吸附模型。吸附过程焓变ΔH为7. 67 kJ·mol-1,ΔS为24. 92 J·mol-1·K-1,ΔG<0,表明稻壳灰吸附剂对Rh B的吸附过程是自发的吸热熵增过程;吸附过程可在20 min内达到平衡,符合准二级动力学模型;吸附过程的活化能Ea为24. 1 kJ·mol-1。吸附容量随着溶液离子强度的增大而减小,说明其吸附是以静电作用为主的吸附过程。10次循环使用后稻壳灰吸附剂对Rh B的吸附效率仍能保持91%以上,表明该材料可以多次循环使用,是潜在的高效吸附材料。
【Abstract】 In this paper,a facile method for the preparation of rice husk ash absorbent,from waste of power generation as raw material and NaOH as activator,was reported. The obtained absorbent was used for the removal of Rhodamine B( Rh B) in water. The effects of pH value,the initial concentration of Rh B,contacting time,contacting temperature and coexisted ions were intensively investigated.The results indicated that the adsorptive properties of the obtained absorbent were highly pH dependent and reached optimum at pH 3. 0. The maximum adsorption capacity reached 322. 6 mg·g-1. The adsorption data of the obtained absorbent were well fitted with the Langmuir isotherm.Thermodynamic studies suggested that the adsorption process of Rh B was endothermic( ΔH> 0,7. 67 kJ·mol-1),entropy favored( ΔS>0,24. 92 J·mol-1·K-1),and spontaneous( ΔG<0) in nature.Adsorption processes reached equilibrium within 20 mins and the kinetic data were well fitted to the pseudo-second-order model.The activation energy( Ea) for the Rh B removal was found to be at 24. 1 kJ·mol-1. The adsorption process of Rh B was highly affected by the ionic strength of the solutions.The adsorption capacity decreases with the increase of ionic strength of solution,indicating the adsorption mechanism of Rh B could be mainly related with electrostatic attraction.The recycle of the obtained absorbent had been investigated and showed that the adsorption efficiency remained above 91%after 10 cycles,which indicated it could be reused.It should be expected to be very promising material for the removal of Rh B in wastewater.
【Key words】 rice husk ash absorbent; Rhodamine B; adsorption; electrostatic interaction;
- 【文献出处】 化学研究与应用 ,Chemical Research and Application , 编辑部邮箱 ,2019年08期
- 【分类号】X703;O647.33
- 【被引频次】17
- 【下载频次】387