High-value zeolitic material from bagasse fly ash: utilization for dye elimination.

Bagasse fly ash (BFA), a sugar industry waste, was used to prepare zeolitic material (ZFA) by means of alkaline hydrothermal treatment. ZFA showed improved morphology as a result of this treatment. The adsorption of the reactive dyes turquoise blue (TB) and brilliant magenta (BM), on both BFA and ZFA, was investigated in a batch contact system. A series of batch experiments revealed that optimal dye removal occurs at a 200 mg/L to 300 mg/L solute concentration, 60 minutes of agitation time, 5 g/L to 10 g/L adsorbent dose, a pH level of 2 to 4, and a temperature of 298 K. ZFA showed enhanced adsorption capacity as compared to BFA. According to the Langmuir equation, the maximum adsorption capacity was 12.66 mg/g and 45.45 mg/g for turquoise blue and brilliant magenta dyes, respectively, on BFA; and 21.74 mg/g and 100.00 mg/g for turquoise blue and brilliant magenta dyes, respectively, on ZFA. Kinetic studies showed that the correlation coefficients best fit with the pseudo-second-order kinetic model, confirming that the adsorption rate was controlled by a hemisorptions process.

Sorptive removal of nickel onto weathered basaltic andesite products: kinetics and isotherms.

The suitability of weathered basaltic andesite products (WBAP) as a potential sorbent was assessed for the removal of Ni (II) from electroplating industrial wastewater. A model study based on the batch mode of operation was carried out for Ni (II) removal from aqueous solution. The effect of various parameters such as hydronium ion concentration, shaking time, sorbent dose, initial Ni (II) concentration, and temperature on the sorption process was studied. At optimised conditions of the various parameters, the industrial wastewater loaded with Ni (II) was sorbed onto WBAP. Thermodynamic parameters for the sorption process were evaluated. Freundlich, Langmuir, Temkin, and Dubinin-Kaganer-Radushkevich isotherms were applied to the sorption pattern on the WBAP. The sorption dynamics of the process was evaluated by applying Lagergren, Bangham, and Weber & Morris equations. The sorption process follows Pseudo-second-order rate of surface diffusion which is identified as the predominating mechanism. The sorption process was found to be reversible by the recovery of sorbed Ni (II) upon extraction with 0.5 MHNO3. The sorbent before and after sorption, was characterized by Fourier transform infrared (FTIR), Powder X-Ray diffraction PXRD), and Thermogravimetric analysis (TGA) methods. The change in surface morphology and crystallanity of the mineral after sorption was analyzed by Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). Based on the previous model study, an electroplating industrial effluent was successfully treated with WBAP to minimize the pollution load caused by Ni (II).