Abstract
Date palm waste-derived biochar (DBC) was produced through pyrolysis (600 degrees C) and modified with zeolite (Z-DBC), silica (S-DBC), or nano-zerovalent iron (nZVI-DBC) to design efficient sorbents. The pristine and engineered biochars were characterized by SEM, XRD, BET, TGA, CHNS-O, and FTIR to investigate the surface, structural, and mineralogical composition. The nZVI-DBC exhibited lowest pH (6.15) and highest surface area (220.92m(2)g(-1)), carbon (80.55%), nitrogen (3.78%), and hydrogen (11.09%) contents compared with other biochars. Isotherm sorption data for chlortetracycline (CTC) removal from aqueous solutions was described well by Langmuir and Redlich-Peterson isotherms showing the highest fitness (R-2 values in the range of 0.88-0.98 and 0.88-0.99, respectively). Langmuir predicted maximum CTC adsorption capacity was in order of nZVI-DBC (89.05mgg(-1)) > S-DBC (45.57mgg(-1)) > Z-DBC (30.42mgg(-1)) > DBC (28.19mgg(-1)). Kinetics adsorption data was best described by power function model (R-2=0.93-0.99), followed by interaparticle diffusion (R-2=0.85-0.96) model. The nZVI-DBC performed outclass by removing 98% of CTC, followed by S-DBC (68%), Z-DBC (35%), and DBC (36%). Chemisorption, H-bonding, and interaparticle diffusion were the operating mechanisms for CTC adsorption onto DBC, S-DBC, and Z-DBC, while - electron donor-accepter interactions and redox reactions augmented these mechanisms for highest CTC adsorption onto nZVI-DBC. Therefore, nZVI-DBC may serve as an efficient green technology for the removal of CTC from aqueous solutions and to reduce surface date palm waste pollution.