Recovery of lanthanum(III) from aqueous solution using biosorbents of plant and animal origin: Batch and column studies

The present investigation attempts to recover lanthanum(III) from aqueous environments using biosorbents of animal (fish scales) and plant origin (neem saw dust). Optimization experiments were carried out using a log transformed 5-level Box-Behnken design. Maximum La(III) uptake was noted to be 200.0 mg/g in the case of fish scales (FS) and 160.2 mg/g in the case of neem sawdust (NS) under optimum conditions (pH: 6.0, biomass dosage: 0.3 g/L; 0.2 g/L, initial metal concentration: 300 mg/L; 250 mg/L, temperature: 50 degrees C, time: 4 h; 3 h). A low p-value of <0.0001 validated the significance of the model. The process was found to follow a homogeneous chemical mode in the case of FS whereas heterogeneity and physisorption was noted in the case of NS. This was further confirmed by scanning electron microscopy (SEM). High uptake values in the case of FS could be attributed to the involvement of both intraparticle and film diffusion. Thermodynamic studies showed that the process is endothermic and spontaneous in the case of both the adsorbents. FTIR analysis confirmed a major involvement of the participation of amide, amines, alkines, aliphatic compounds and alkyl groups during La(III) biosorption. Maximum adsorption efficiency and recovery of La(II) from ceramic industrial effluent using FS were noted as 88.5% and 84.6% which were obtained in column mode at a flow rate of 1 ml/min, bed height of 12 cm and 0% dilution. Regeneration studies suggested that the biosorbent FS could be consistently reused up to 6 cycles, (C) 2014 Elsevier Ltd. All rights reserved.