响应面优化制备花生壳纤维素及其对罗丹明B的吸附性能

Optimization of the preparation of peanut shell cellulose via response surface methodology and its adsorption properties to Rhodamine B

以废花生壳为原料制备了花生壳纤维素吸附剂并将其用于去除水中水中罗丹明B(Rhodamine B,RhB)染料。采用Box-Behnken Design(BBD)响应面法(RSM)法对制备条件进行了优化,筛选出获得吸附效果最佳的花生壳纤维素的制备条件。系统考察了溶液的pH值,初始浓度、吸附时间以及溶液离子强度对其吸附性能的影响。结果表明:pH=4时,花生壳纤维素对RhB的吸附效果最佳,饱和吸附容量qm为166.7 mg·g^-1;与RSM模型预测值吻合。吸附过程可在30 min内达到平衡,符合准二级动力学模型。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次循环使用后花生壳纤维素对RhB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。

In this paper,a facile method for the preparation of cellulose from waste peanut shell was reported.The optimization of the preparation process of the peanut shell cellulose to obtain the highest adsorption capacity was carried out by Box-Behnken Design(BBD)response surface methodology(RSM).The prepared peanut shell cellulose was used as adsorbent for the removal of Rhodamine B(RhB)in water.The effects of pH value,the initial concentration of RhB,contacting time,and coexisted ions were intensively investigated.The results indicated that the adsorptive properties of the obtained cellulose were highly pH dependent and reached optimum at pH 4.0.Adsorption processes reached the equilibrium within 30 min.The adsorption data of the obtained cellulose were well fitted with the Langmuir isotherm.The maximum adsorption capacity calculated from Langmuir isotherm was 166.7 mg·g^-1,which is consistent with the predicted value of RSM model.The adsorption process of RhB was highly affected by the ionic strength of the solutions,indicating that the adsorption mechanism of RhB could be mainly related with electrostatic attraction.The recycle of the obtained cellulose has been investigated and showed that the adsorption efficiency remained above 91%after 10 cycles.It should be expected to be very promising material for the removal of RhB in wastewater.