CADMIUM(II) removal from aqueous solution by adsorption on water hyacinth (Eichhornia crassipes) hydrochar modified with citric acid

Abstract

This study is focused on synthesizing biosorbents from water hyacinth (Eichhornia crassipes), WH. Three biosorbents were obtained: WH modified with citric acid (WH-CA), hydrocarbonized WH (WHHC), and WHHC modified with CA (WHHC-CA). The capacity of these biosorbents to adsorb Cd(II) from water solutions was ascertained. WH and WHHC were modified hydrothermally using 2, 1 and 0.5 M CA solutions and were designated using CA concentration. All biosorbents were characterized using various techniques. At pH = 6 and 25 °C, WHHC-CA1 exhibited the highest capacity for adsorbing Cd(II) of 166.6 mg/g, so the optimal CA concentration is 1 M.