Chitosan sorbents for platinum sorption from dilute solutions
Chitosan sorbents for platinum sorption from dilute solutions
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DOI：
10.1021/ie990165k
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发表时间：
1999-10-01
影响因子：
4.2
通讯作者：
Tobin, JM
中科院分区：
文献类型：
--
作者：
Guibal, E;Larkin, A;Tobin, JM
壳聚糖已被证明能有效去除稀废水中的铂。最大摄取能力达到300 mg g(-1)（约1.5 mmol g(-1)）。吸附的最佳pH为pH 2。戊二醛交联预处理是在酸性溶液中稳定生物聚合物的必要条件。研究了吸附等温线与pH、吸附剂粒径和交联比的关系。令人惊讶的是，交联的程度（由交联剂在处理液中的浓度决定）对吸收能力没有显著影响。氯离子或硝酸盐等竞争阴离子会导致吸附效率大幅下降。吸附动力学还表明，增加交联比或吸附剂粒径对吸附剂的吸收率没有显著影响。传质速率受到初始铂浓度和生物聚合物调节的显著影响。凝胶球调节似乎降低了吸附速率。钼酸盐和钒酸盐离子的传质受粒子内传质控制，铂离子的传质受外扩散和粒子内扩散控制。与前一种离子相比，铂不形成多核水解物质，这是负责扩散到聚合物网络的空间位阻。
Chitosan has proved efficient at removing platinum in dilute effluents. The maximum uptake capacity reaches 300 mg g(-1) (almost 1.5 mmol g(-1)). The optimum pH for sorption is pH 2. A glutaraldehyde cross-linking pretreatment is necessary to stabilize the biopolymer in acidic solutions. Sorption isotherms have been studied as a function of pH, sorbent particle size, and the cross-linking ratio. Surprisingly, the extent of the cross-linking (determined by the concentration of the cross-linking agent in the treatment bath) has no significant influence on uptake capacity. Competitor anions such as chloride or nitrate induce a large decrease in the sorption efficiency. Sorption kinetics show also that uptake rate is not significantly changed by increasing either the cross-linking ratio or the particle size of the sorbent. Mass transfer rates are significantly affected by the initial platinum concentration and by the conditioning of the biopolymer. Gel-bead conditioning appears to reduce the sorption rate. While for molybdate and vanadate ions, mass transfer was governed by intraparticle mass transfer, for platinum, both external and intraparticle diffusion control the uptake rate. In contrast with the former ions, platinum does not form polynuclear hydrolyzed species, which are responsible for steric hindrance of diffusion into the polymer network.