Sequential Removal of Oppositely Charged Multiple Compounds from Water Using Surface-Modified Cellulose

Efficient removal of organic and inorganic pollutants is a challenge owing to the involvement of different physicochemical properties. Herein, we discuss a novel approach for successive adsorption of oppositely charged multiple compounds [acid fuchsin (AF), Cu­(II), perylene tetracarboxylate (PTC) anions, and Zn­(II) ions] from water using chemically modified cellulose fibers (PEI/CE). The changes in net surface charges of the adsorbent accompanied by the successive adsorption of oppositely charged compounds from water are utilized as a concept for adsorption of multiple pollutants on the same adsorbent. The PEI/CE adsorbent was separated via simple filtration after each adsorption experiment and used directly for further successive adsorption without any drying or surface treatments. Compared to most of the reported adsorbents, PEI/CE fibers showed excellent adsorption capacities of 562, 552, 216, and 157 mg/g for AF, Cu­(II) ions, PTC dye, and Zn­(II) ions, respectively. Analysis of the data from kinetic and isotherm studies revealed the best fit to the pseudo-second-order and Langmuir isotherm model for all adsorbates. Furthermore, data from the zeta potential measurements and elemental analysis helped to establish the mechanism of the adsorption process. Such concepts are viable for the removal of known pollutants from multiple industrial effluents. A series of such simple, renewable adsorbents and successive adsorption processes could be developed as a new platform for effective removal of several pollutants from wastewater effluents