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Chemically modified Lagenaria vulgaris shell (ccLVB) was tested as a new sorbent for the removal of Ni(II) from aqueous solution, in batch conditions. The sorption process was very fast reaching equilibrium in about 20 min. Ni(II) sorption is almost invariant in the pH range from 3 to 6. Sorption kinetics followed pseudo-second order, intraparticle diffusion and Chrastil’s models, which suggest that both surface reaction and diffusion were the rate-limiting steps. Equilibria experimental results are well fitted by Langmuir and Temkin sorption isotherm models, indicating mixed adsorption process. The maximum biosorption capacity of ccLVB for Ni(II) was found to be 84.51 mg g-1. The calculated thermodynamic parameters showed that the biosorption of nickel on ccLVB was feasible, spontaneous and exothermic at 25-45ºC. The desorption experiments showed that the ccLVB could be reused for five cycles without significant loss in sorption capacity. Release of Na+ ions from the biosorbent during sorption of Ni(II) reveals that the main sorption mechanism is ion exchange. Presented study suggests that ccLVB can be used effectively for the removal of Ni(II) ions from aqueous solution.

The effectivness of UV/H2O2 process, Fenton and photo-Fenton process at decolorization of commercially important textile dyes Reactive Orange 4 (RO4) and Reactive Blue 19 (RB19) was evaluated. The effect of operational condition such as initial pH, initial H2O2 concentration, initial Fe2+ concentration and initial dye concentration on decolorization of RO4 and RB19 was studied. The photo-Fenton process is found to be more efficient than UV/H2O2 and Fenton process for decolorization of simulated dye bath effluent and solutions of the dyes in water alone under optimum conditions. In simulated dye bath the removal efficiency was slightly lower than for the solutions of the dyes in water alone for both dyes types. The results revealed that the tested advanced oxidation processes were very effective for decolorization of RO4 and RB19 in aqueous solution. [Projekat Ministarstva nauke Republike Srbije, br. TR34008]

A new biosorbent, abbreviated as LVB-ZrO2,was synthesized by chemically modifying Lagenaria vulgaris shell with ZrO2. The removal of textile dye RB19 from aqueous solution by LVB-ZrO2 was studied. Characterization by SEM, FTIR and XRD confirmed the chemical modification of the biomaterial, which showed significant improvement of removal efficiency compared with unmodified Lagenaria vulgaris shell. LVB-ZrO2 point of zero charge is 5.49. The biosorption process is highly pH dependent and the optimal pH is 2.0, at which complete dye removal was attained. The results are the best by a pseudo-second order kinetic model. The optimal adsorbent dosage is 4 mg/dm³. The RB19 biosorption follows the Langmuir isotherm model (R²=0.9978), with the maximum sorption capacity of 75.12 mg/g. LVB-ZrO2 is a mechanically stable, easy to synthesize, cost-effective, biocompatible and environmentally-friendly biosorbent with the high potential for the removal of RB19 from aqueous solution. [ABSTRACT FROM AUTHOR]

A new biosorbent, abbreviated as LVB-ZrO₂, was synthesized by chemically modifying Lagenaria vulgaris shell with ZrO₂. The removal of textile dye RB19 from aqueous solution by LVB-ZrO₂was studied. Characterization by SEM, FTIR and XRD confirmed the chemical modification of the biomaterial, which showed significant improvement of removal efficiency compared with unmodified Lagenaria vulgaris shell. LVB-ZrO₂point of zero charge is 5.49. The biosorption process is highly pH dependent and the optimal pH is 2.0, at which complete dye removal was attained. The results are the best by a pseudo-second order kinetic model. The optimal adsorbent dosage is 4 mg/dm³.The RB19 biosorption follows the Langmuir isotherm model (R² = 0.9978), with the maximum sorption capacity of 75.12 mg/g. LVB-ZrO₂is a mechanically stable, easy to synthesize, cost-effective, biocompatible and environmentally-friendly biosorbent with the high potential for the removal of RB19 from aqueous solution.