Aluminum Pillared Palygorskite-Supported Nanoscale Zero-Valent Iron for Removal of Cu(II), Ni(II) From Aqueous Solution

A new composite clay, aluminum pillared palygorskite-supported nanoscale zero-valent iron (Al–P-nZVI), was prepared by reducing ferric ion (FeCl3.6H2O) to Fe0 with sodium borohydride (NaBH4) on aluminum pillared palygorskite, in order to improve metal ions adsorption capacities of palygorskite and reduce nanoscale zero-valent iron reunion. The composite clay was characterized by FTIR, TEM and XRD spectra. Batch isothermal equilibrium adsorption experiments were conducted to evaluate the clay adsorbent for the removal of Cu(II) and Ni(II) from water. The effects of pH, shaking time on adsorption capacity were also investigated. The pseudo-second-order model was relatively suitable for describing the reaction process. The equilibrium adsorption data were fitted to Langmuir adsorption models. The maximum adsorption capacities of aluminum pillared palygorskite-supported nanoscale zero-valent iron sorbent as obtained from Langmuir adsorption isotherm were found to be 787 and 704 mg g−1 for Cu(II) and Ni(II), respectively. A comparison of the results of the present investigation with those reported in the literature showed that Al–P-nZVI exhibits greater adsorption capacity for Cu(II)and Ni(II). These results demonstrated that Al–P-nZVI could potentially be used as an effective material for environmental remediation.