Synthesis of new alginate-silver nanoparticles/mica (Alg-AgNPs/MC) bionanocomposite for enhanced adsorption of dyes from aqueous solution

Abstract

Wastewater treatment is of utmost importance in providing equitable and safe drinking water to all. In that bid, herein, a novel and potential Alginate-Silver nanoparticle/Mica (Alg-AgNPs/MC) bio-nanocomposite has been synthesized by the green method. The synthesized nanocomposite was further harnessed for the removal of methylene blue (MB) and brilliant green (BG) dyes from an aqueous solution for the first time and has not been reported in literature till now. The Alg-AgNPs/MC bionanocomposite was thoroughly characterized through FTIR, SEM-EDX, TEM, XRD, and TGA/DTA analysis. Moreover, Alg-AgNPs/MC bionanocomposite was further employed to remove both dyes from the aqueous solution in batch mode. The Alg-AgNPs/MC bionanocomposite could remove 99.07% of MB and 91.53% of BG at an initial concentration of (20 mg L−1), adsorbent dosage (0.01 g), time (180 min), pH-8 for MB dye and pH-9 for BG. The Alg-AgNPs/MC bionanocomposite achieved maximum adsorption capacities of 352 and 249 mg g−1 for BG and MB dyes, respectively. The equilibrium adsorption data for both dyes were best fitted to the Freundlich model with R2, 0.9945 and 0.9799 for BG and MB dyes, respectively. The adsorption dynamics were best followed by a pseudo second order kinetic model for both dyes. The positive value of thermodynamic parameter ΔH indicates the process to endothermic and spontaneous in nature. The exhausted Alg-AgNPs/MC bionanocomposite can be regenerated up to the 4th cycle successfully.