改性荔枝皮对水中Pb(Ⅱ)的动态吸附特性  

Biosorption of Pb(Ⅱ) by Modified Lychee Pericarps in Fixed-Bed Columns

作　　者：孔郑磊 李晓晨[1] 杨继利[1] 潘新革[1] 

机构地区：[1]山东农业大学水利土木工程学院,山东泰安271018

出　　处：《环境科学研究》2014年第10期1186-1192,共7页Research of Environmental Sciences

基　　金：国家自然科学基金青年项目(51208174)

摘　　要：以改性荔枝皮为吸附剂对Pb(Ⅱ)进行固定床动态吸附试验,考察了填料柱高(3.1、5.2和10.4 cm)、Pb(Ⅱ)溶液进水流速(2、4和6 mLmin)和初始ρ〔Pb(Ⅱ)〕(50、100和200 mgL)对Pb(Ⅱ)的吸附穿透曲线和传质区长度的影响.结果表明:降低柱高、增大流速、增大初始ρ〔Pb(Ⅱ)〕均会使穿透时间提前;柱高、流速和初始ρ〔Pb(Ⅱ)〕引起的传质区长度的平均变化率绝对值分别为0.076、0.090和0.004,可见与初始ρ〔Pb(Ⅱ)〕相比,柱高和流速对传质区长度的影响更大.吸附穿透曲线的试验数据符合Thomas模型的使用条件(R2>0.95),吸附容量实测值(qexp)大于59.1 mgg,与Thomas模型预测值(qcal)较为接近,说明内部扩散和外部扩散均非该吸附过程的限速步骤.在仅改变流速或者初始ρ〔Pb(Ⅱ)〕时,穿透时间预测值和实测值间的最大误差分别为7.14%和8.45%,表明可以通过BDST(bed depth service time)模型确定固定床的使用周期.Modified lychee pericarps were employed for the adsorption of Pb（ Ⅱ） using fixed-bed columns,and the effects of column heights（ 3. 1,5. 2 and 10. 4 cm）,flow rates（ 2,4 and 6 mLmin） and initial concentrations（ 50,100 and 200 mgL） on the breakthrough curve,as well as mass transfer zone lengths,for Pb（ Ⅱ） adsorption were investigated. The results showed that the breakthrough time would be shortened by reducing column height and increasing the flow rate and initial concentration. The average changing rate of height of mass transfer zone was under the three conditions of initial Pb（ Ⅱ） concentration,column height and flow rate0. 076,0. 090 and 0. 004,respectively. This result showed that compared with the initial Pb（ Ⅱ） concentration,column height and flow rate imposed more significant effects on the height of mass transfer zone. The column data were well fitted by the Thomas model（ R20. 95）,with the experimental values（ qexp） being more than 59.1 mgg,and there was satisfactory coherence between the experimental and theoretical values（ qcal）. This indicated that neither external nor internal diffusions were the limiting step for the adsorption processes. The bed depth service time（ BDST） model was applied to predict the breakthrough time under different conditions. The results showed that the maximum error between the predicted and experimental values of breakthrough time were 7. 14% and 8. 45%,respectively,with reference to changing flow rates or initial concentrations.

关 键 词：荔枝皮 吸附 Pb(Ⅱ) 填料柱 Thomas模型 BDST模型 

分 类 号：X712[环境科学与工程—环境工程]