Modeling and mechanism of the adsorption of copper ion onto natural bamboo sawdust
2012; Elsevier BV; Volume: 89; Issue: 1 Linguagem: Inglês
10.1016/j.carbpol.2012.02.069
ISSN1879-1344
AutoresXue-Tao Zhao, Teng Zeng, Xue-Yan Li, Zhangjun Hu, Hongwen Gao, Zhi Xie,
Tópico(s)Advanced Cellulose Research Studies
ResumoThe sorption of copper ions onto natural bamboo sawdust with cellulose–lignin polymeric structure strongly depends on pH. The adsorption capacity for copper ions increases as increasing pH and copper loadings. The fitting of copper pH boundary curve by NEM surface complexation models shows that: three-sites model including the ion exchange reaction of permanent charge fits better than two-sites model. The incorporation of the hydrated ion reaction gives better fitting results. XAFS study shows that: copper ions mainly form inner complexation with sawdust, but there is no obvious evidence on the complexation of carboxylic acid groups with copper ions. EXAFS fitting result shows that: as pH rises, the spatial configuration of copper ions shifts from tetrahedron to octahedron. Meanwhile the increase in the coordination number indicates that hydrated copper ions participate in the adsorption. Both XANES and EXFAS spectrum offer a similar explanation for copper adsorption in the range of experimental and fitting errors.
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