Zn-doped aerogel for Ni2+ adsorption (Zn-A-Ni) and reuse of Zn-A-Ni to create Zn, Ni-co-doped carbon aerogel for applications in adsorption and energy storage

Abstract

In order to solve the problem of heavy metal pollution, in this study, Zn-doped aerogel (Zn-A) was used as a material to remove Ni²⁺ from wastewater. Zn-A was synthesized from sodium alginate and nipa palm shell-derived cellulose via the sol–gel method combined with freeze-drying. Zn-A has the ability to adsorb Ni²⁺ up to 194.2 mg/g (Zn-A-Ni). After adsorbing Ni²⁺, Zn-A-Ni was pyrolyzed to form Zn, Ni-co-doped carbon aerogel (Zn-CA-Ni), which has high potential for manufacturing electrodes in supercapacitors (specific capacitance reaches 124.0F/g) and crystal violet treatment (adsorption capacity reaches 38.7 mg/g). Furthermore, Zn-A and Zn-CA-Ni were characterized through modern methods: Scanning electron microscope, energy dispersive X-ray, Fourier-transform infrared spectroscopy, X-ray diffraction analysis, and Nitrogen adsorption–desorption isotherm. The ability to adsorb Ni²⁺ of Zn-A and adsorb crystal violet of Zn-CA-Ni was determined through ultraviolet–visible spectroscopy measurement. In addition, the electrochemical properties of Zn-CA-Ni were also analyzed through cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy.