Facile preparation of hierarchical polyaniline-lignin composite with a reactive silver-ion adsorbability

A hierarchical polyaniline-lignin (PANI-EHL) composite was facilely prepared from aniline and enzymatic hydrolysis lignin in an aqueous solution of ammonia. The morphology, FTIR, UV-vis spectra, thermogravimetric analysis, and wide-angle X-ray diffraction analyses of the composite were systematically investigated. Furthermore, the sorption property of the PANI-EHL composite for silver ions in aqueous solution was studied via a static sorption technique. The result demonstrated that the PANI-EHL composite possessed a strongly reactive sorption characteristic for silver ions. Serrated silver threads with length up to 10 mm were obtained by using the PANI-EHL composite as a low-cost adsorbent. Moreover, the role of EHL and polyaniline in the PANI-EHL composite for silver ions sorption was investigated. The investigation indicated that the EHL unit could play a vital role in the chelation of silver ions, whereas the polyaniline unit played a leading role in redox sorption.