Polyethyleneimine-Modified Garden WasteBiochar: Preparation and Its Applicationfor Aqueous Cr(Ⅵ) Adsorption

Garden Waste (GW) and Polyethyleneimine were used as source materials to create polyethyleneimine-modified garden waste biochar (PGWBC).The composite was employed as an adsorbent in both static and dynamic Cr(VI) adsorption experiments after being evaluated using N 2 adsorption-desorption and Fourier transform infrared spectroscopy.The material characterization results indicated that PGWBC was a mesoporous material that contained mainly narrow slit mesopores.The static adsorption data indicated that Cr(VI) adsorption by PGWBC was a pH-dependent process, a rise in pH from 2 to 9 resulting in a decrease in Cr(VI) adsorption from 44.6 mg/g to 3.8 mg/g.The adsorption process was endothermic and spontaneous, as characterized by the pseudo-second-order model and the Langmuir equation, the maximum Cr() uptake was 56.1 mg/g in 308 K.The dynamic adsorption revealed that increasing the flow rate impaired Cr(VI) adsorption, and the Thomas model was more suited to represent Cr(VI) adsorption by PGWBC than the Yoon-Nelson model.