Honeycomb like CdS/sulphur-modified biochar composites with enhanced adsorption-photocatalytic capacity for effective removal of rhodamine B

Honeycomb like CdS/Sulphur-modified biochar composites (CdS/S-BC) with excellent adsorption-photocatalytic activity was prepared by impregnation and calcination methods. Sulphur-modified biochar (S-BC) has manifested the high porosity and large specific surface area because of the modification of S. 1-CdS/S-BC (1 represents the CdS molar amount) exhibits high synergistic adsorption-photocatalytic degradation effect for RhB, and the RhB removal efficiency of 1-CdS/S-BC up to 99.18% within 60 min under visible light (λ ≥ 420 nm) irradiation. Compared with single materials BC, S-BC, CdS, the outstanding RhB removal performance of 1-CdS/S-BC was not only ascribed to the large specific surface area and abundant reactive sites provided by S-BC, but also can significantly promote the migration and utilization of photoinduced carriers. The CdS/S-BC adsorption mechanism studies demonstrated that hydrogen bond and electrostatic interaction are main action of adsorption, meanwhile the superoxide radicals (·O2-) are the main active species in the photocatalytic degradation process. This study provided an available strategy for the efficient utilization of green biomass to prepare adsorption-photocatalytic materials.