Preparation of bichar/layered double hydroxide@alginate aerogel as a highly efficient adsorbent for Cu2+ and Cd2+

Abstract Calcium cross‐linked layered double hydroxide‐bichar/alginate aerogel (LBCA) was synthesized by ultrasonic‐assisted hydrothermal and freeze‐drying method. The Mg‐Al layered double hydroxide (LDH) was successfully loaded on the bichar (BC) and the LDH‐BC was dispersed uniformly in the calcium alginate aerogel, which was confirmed by X‐Ray Diffraction, scanning electron microscopy and BET tests. The obtained LBCA was applied to remove the Cu 2+ and Cd 2+ in the aqueous solution. As compared with LDH nanosheets, removal rates of LBCA aerogel on Cu 2+ and Cd 2+ were ranged from 59% to 94% and 45% to 86%, respectively. The adsorption kinetic data accorded with the pseudo second‐order kinetic equation, and the isotherm data were in good agreement with the Langmuir model. Moreover, LBCA aerogel showed good regeneration ability, and raw materials for the fabrication of LBCA aerogel are abundant and low price.