摘要
采用改进的滴加成球法合成壳聚糖树脂,用环氧氯丙烷对树脂进行交联,制备新型壳聚糖交联树脂。研究了交联树脂对Cr(VI)的吸附效果,探讨了溶液pH值、吸附时间、温度、Cr(VI)初始质量浓度等因素对吸附性能的影响及吸附热力学和动力学。结果表明,各因素中pH值对壳聚糖交联树脂吸附Cr(VI)影响较大。对初始质量浓度为120mg/L的Cr(VI)溶液,壳聚糖交联树脂投加量为1 g/L,pH=3,温度为25℃,吸附2h时可达到最大吸附容量(72mg/g)。用Langmuir等温模型和Pseudo second-order动力学模型对树脂的吸附过程进行线性拟合,R2分别为0.999 9和0.999 7,模型计算的饱和吸附容量qmax(73.53 mg/g)和平衡吸附量qe(29.23 mg/g)与试验结果(72.10 mg/g和27.73 mg/g)基本吻合。Fick扩散模型表明,树脂对Cr(VI)的吸附可分为3个阶段,说明Cr(VI)的去除是物理吸附和化学吸附共同作用的结果。
In this study, a kind of novel chitosan cross-linked resin was prepared by an improved drop-sphere-forming method, epichloro- hydrin was used to cross-link the resin in enhancing its rigidity. The characterization of chitosan cross-linked resin showed that the specific surface area and the mean diameter of the pores of the resins were 1.59 m2/g and 20 nm, respectively. Besides, the average diameter of the resin particles was 0.2 mm. The adsorption of Cr（VI） onto the cross-linked chitosan has been investigated. The resin showed a high- er affinity towards the uptake of Cr（VI） from the simulated wastewater, but the adsorption ability was influenced by time, pH value, temperature and the initial concentration of the solution. The results showed that the pH was the main influencing factor, and the maxi- mum adsorption was observed at a pH value of 3,0; in addition, the temperature has also influenced the adsorption ability. The chitosan resins were added in the solution as initial concentration as 120 mg/L, at pH = 3 and 25 ℃ with an adsorbent dosage of 1 g/L. The system underwent an upward trend dramatically for 2 hours, and the adsorption capacity reached the highest point at 72 mg/g. Under the room temperature, the data of the equilibrium sorption experiments was fitted well with Langrnuir isotherm, and the related coefficient of the model was 0.999 9. Besides, under the adsorption temperatures of 25 ℃, the experimental kinetic data were well correlated with Pseudo-second-order model, and the related coefficient of the model was 0.999 7. Fick diffusion law describes the adsorption reactions take place through 3 steps ： （i） external film diffusion, （ii） intra- particle diffusion and （iii） interaction between adsorbate and active site （--NH2）. The results shown the cross-linked chitosan resin could remove Cr（VI） efficiently and the removal of Cr（VI） may inelude both physical adsorption of Cr（VI） on the surface or inside of the resin and ion exchange between Cr（VI） and the chitosan resin.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2012年第6期72-76,共5页
Journal of Safety and Environment
基金
国家水体污染重大专项(2009ZX07210-004-02)
