Enhanced Biosorption of Pb(II) Ions from Aqueous Solutions onto Citric Acid Treated Aspergillus niger Biomass: Equilibrium and Kinetic Studies

In the present study, initially Aspergillus niger was tested for biosorption of Pb(II) ions and then studied the effect of pretreatment for enhanced biosorption. It was found that the maximum biosorption potential was achieved with citric acid treatment (70.56 %) in comparison with the biomass without treatment (65.46 %) at a biosorbent dose of 20 mg/L, pH 4, 100 rpm, 37 ºC for 8 h. The optimized conditions for treated Aspergillus niger were determined by optimizing the biosorption parameters such as pH, temperature, biomass dose, incubation time and agitation speed. This study indicates that the citric acid treated Aspergillus niger is an effective biosorbent for removal of lead (II) at optimized conditions with the maximum biosorption potential of 83.6 % as compared to previous reported work. SEM-EDX and FTIR analysis showed the structural variations and the functional groups involved in lead biosorption, respectively. Biosorption kinetics showed that pseudo second order kinetic model as the better fit.

Mathematical modeling and thermodynamic study of copper (II) removal from aqueous solution by Coriandrum Sativum seeds

Coriandrum Sativum seeds (CSS), were tested as a new eco-friendly adsorbent of copper ions from aqueous solutions. Hence, the effect of the most influencing experimental parameters such as initial concentration of Cu (II) and the temperature was studied upon the adsorption process in order to use its results in following studies. Lagergren pseudo-first-order, pseudo-second-order, and Intraparticle diffusion models were used to describe the biosorption kinetics. The adsorption process was also analyzed by Langmuir, Freundlich and Temkin models and the maximum monolayer biosorption capacity of CSS was found to be 33,5 mg. g−1 by using the Langmuir model. So as to investigate the thermodynamic properties of the adsorption process, the Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) values in the temperature range of 25-55C° were also calculated in order to conclude the process characteristics. SEM and EDAX analysis were effectuated in order to study the surface morphology of CSS before and after the adsorption process.