▎ 摘　　要

The hydroxyapatite (HAp) was conjugated on carboxylated graphene nanoplatelets (Gra-C to GHAp) or multi-wall carbon nanotubes (CNT-C to CHAp) by its in-situ synthesis using the wet-chemical precipitation method, to increase their surface areas and, thus, negatively-charged active sites for adsorption of cationic pollutants as dyes from a water solution. Various characterization techniques have been utilised for the analysis of crystallinity, bulk and surface chemistry, as well as the morphological structure of synthesized nanocomposites, while Rhodamine 6G was used in adsorption experiments as target pollutant to study. The results show much higher adsorption capacity (90 mg g(-1)) for GHAp, compared to CHAp (59 mg g(-1)) or their original counterparts (6.5 mg g(-1)1 for HAp, 25 mg g(-1) for Gra-C, 20 mg g(-1) CNT-C), be related to quantitatively higher electrostatic attraction of dye molecules with the surface located carboxylic and phosphorus groups from Gra-C and equally distributed HAp particles, respectively, resulting to a monolayer adsorption capacity and heterogeneous sorption. Pseudo-second-order kinetic and Freundlich isotherm model are revealed to be the best described their adsorption behavior. The reusability of nanocomposites was also confirmed by up to 77% of adsorption efficiency after three repeated desorption and regeneration cycles, indicating them as a promising adsorbent for dyes removal from wastewater.