Removal of Cu (II) from Aqueous Solution Using a Novel Crosslinked Alumina-Chitosan Hybrid Adsorbent

A novel biosorbent was developed by coating chitosan, a naturally and abundantly available biopolymer, on to activated alumina based on oil shale ash via crosslinking. The adsorbent was characterized by various techniques, such as Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric-differential thermal analysis, and X-ray photoelectron spectroscope. Batch isothermal equilibrium adsorption experiments were condcted to evaluate the adsorbent for the removal of Cu(II) from wastewater. The effect of pH and agitation time on the adsorption capacity was also investigated, indicating that the optimum pH was 6.0. The equilibrium adsorption data were correlated with Langmuir and Freundlich models. The maximum monolayer adsorption capacity of chitosan coated alumina sorbent as obtained from Langmuir adsorption isotherm was found to be 315.46 mg·g−1 for Cu(II). The adsorbent loaded with Cu(II) was readily regenerated using 0.1 mol·L−1 sodium hydroxide solution. All these indicated that chitosan coated alumina adsorbent not only have high adsorption activity, but also had good stability in the wastewater treatment process.