Synthesis of polyamide grafted on biosupport as polymeric adsorbents for the removal of dye and metal ions

The polymeric composite adsorbent was successfully synthesized by grafting polyamide on eggshell (CMP). The performance of the CMP composite as an adsorbent was studied for the methylene blue (MB) dye removal in a batch mode system. The effects of several factors such as adsorbent dosage, initial concentration of MB dye, and initial solution pH on the efficiency of MB removal were investigated. Kinetic studies were implemented to understand the adsorption mechanism. The maximum adsorption capacity was achieved under the conditions of an initial concentration of 200 ppm, the adsorbent dosage of 0.01 mg, and solution pH of 6 at room temperature. The pseudo-second-order kinetic model showed best fitted the experimental data. The adsorption capacity of the CMP was 345 ± 4 mg/g at 298 K for MB dye. The adsorption mechanisms included π-π interactions, electrostatic attraction, interaction with functional groups, and formation of complexes. The CMP showed simultaneous removal of MB dye and toxic metals such as Pb, Cr, Ni, Cd, Hg, and As. The CMP composite can be potentially used as an efficient and low-cost biosorbent for the removal of MB dye and heavy metals.