Removal of Methylene Blue by Peanut Shell Biochar/Ag3PO4/AgI Composite with Synergic Adsorption/Photocatalysis

Abstract As an effective means to promote photoinduced carrier separation, the construction of Z‐scheme heterojunction photocatalysts can be widely used for the degradation of organic pollutants. In this work, an innovative peanut shell biochar/Ag 3 PO 4 /AgI ternary composite was prepared, and the chemical compositions, structural morphology, optical and photoelectrochemical properties of the photocatalyst were characterized. The peanut shell biochar/Ag 3 PO 4 /AgI composite delivered a high photodegradation efficiency of MB at 99.7 % in 60 min with kinetic constant of 0.0366 min −1 , which is about 3.81, 9.89, and 1.17 times that Ag 3 PO 4 (0.0096 min −1 ), AgI (0.0037 min −1 ) and Ag 3 PO 4 /AgI (0.0313 min −1 ), respectively. Meanwhile, the composite also exhibits excellent photocatalytic activity for methyl orange, rhodamine B, congo red, tetracycline and ofloxacin. Based on radical capture experiments and photoelectrochemical test, the possible photocatalytic mechanism was revealed. Compared with monomers, biochar/Ag 3 PO 4 /AgI exhibits higher photocatalytic degradation activity under visible light irradiation, which was due to the introduction of electron‐transporting biochar into the composite, and the formation of heterostructure between Ag 3 PO 4 and AgI, which enhance the separation rate of photoinduced carriers. The excellent stability and photocatalytic activity make peanut shell biochar/Ag 3 PO 4 /AgI an ideal photocatalyst to solve environmental crisis.