Toxic Cr removal from aqueous media using catechol-amine copolymer coating onto as-prepared cellulose.

Green composite adsorbent with low cost and high efficiency towards toxic Cr(VI) removal from the polluted water has a broad application prospect. In this work, a mussel-inspired Cr-adsorbent namely poly(catechol tetraethylenepentamine-p-phenylenediamine)@as-prepared cellulose (PAC@AC) is successful fabricated via catechol-amine copolymer adhering onto as-prepared cellulose (AC). The detailed characterizations of product are run with SEM, FT-IR, TGA, XRD, EDS and XPS analysis. Many factors are investigated to affect the adsorption of Cr(VI) by PCA@AC, including ratio of AC to PCA, adsorbent dosage, contact time, initial Cr(VI) concentration, pH, temperature and exterior ions. The maximum adsorption capacity of PCA@AC for Cr (VI) is obtained by 507.61 mg/g at 30°C using Langmuir model, which is very higher than the pure AC. The removal ability of PCA@AC is ascribed to the electrostatic interaction and reduction reaction of Cr(VI) to Cr(III) during the adsorption process. In addition, the adsorption process is spontaneous and endothermic, not require any external energy. The composite adsorbent (PCA@AC) has great potential for Cr(VI)-wastewater purification with an excellent chelating ability.