Adsorption potential of neodymium/alginate beads for removal of Congo red and Brilliant blue G from aqueous solution

In this study, neodymium/alginate (Nd/Alg) beads were prepared to removal of Congo Red (CR) and Brilliant Blue G (BBG) dyes from aqueous solution and the adsorption potentials of these dyes were investigated. For this, Nd/Alg beads prepared using crosslinking were characterized by FTIR, SEM–EDS and TGA. For the adsorption of CR and BBG dyes, the effects of various parameters including the amount of Nd in adsorbent (bead), pH, contact time, adsorbent amount, initial dye concentration and temperature were investigated. The optimum conditions for the effective removal of CR and BBG dyes were determined as Nd amount in bead: 3%, pH: 7, contact time: 60 min, bead amount: 15 mg, initial dye concentration: 25 mg/L and temperature 298 K. Adsorption isotherm studies (Langmuir and Freundlich isotherms) and kinetic studies (pseudo-first-order and pseudo-second-order) were carried out under optimum conditions. The adsorption data were found to completely follow Langmuir model for CR and BBG dyes. The maximum adsorption capacities were found to be 46.03 mg/g for CR and 25.25 mg/g for BBG under optimum conditions. The adsorption kinetic data of both dyes were found to be compatible with pseudo-first-order and adsorption processes were explained by intraparticle diffusion. According to thermodynamic studies, nature of adsorption reaction was spontaneous, exothermic and increasing randomness for both dyes. As a result, it can be concluded that Nd/Alg beads obtained with a natural polymer have low cost and high efficiency and even small amounts of these beads have high potential for treatment of high concentration dye wastewater.