Decolorization of multicomponent dye-laden wastewater by modified waste fly ash: a parametric analysis for an anionic and cationic combination of dyes

Abstract

WFA modi cation was done by its reaction with the mixture of ammonia solution and phosphoric acid. BET analysis of modi ed WFA elucidate pore volume and surface area of 0.017cm 3 /g, 11.1m 2 /g respectively. Thermo-Gravimetric Analysis (TGA) con rmed the 45% loss in weight for the WFA whereas, for modi ed WFA, the loss was about 12%. XRD results proposed the improved crystallinity of the modi ed WFA. Moreover, the zeta-potential of -40mV indicates the favorable removal e ciency, against the pH value of 6.41. Regression results from the comparison of order-based kinetic models suggest that nth model parameters justify the complex nature of the adsorption mechanism with its feasible correlation coe cient (R 2 > 0.95) and its lower error values for both single and binary solutions. Monolayer coverage capacities for a single solution system of Methylene Blue (MB), Rhodamine-6G (Rh) and Methyl Orange (MO) were 24.93mg/g, 24.83mg/g and 14.95mg/g respectively. Further, the isothermal model's results suggest that the "Extended Sips" model gives relatively higher R 2 = 0.99 values and deals with the failed assumptions of both the Langmuir and Freundlich models. The thermodynamic model generated results conclude that involved single and binary physisorption processes were spontaneous and endothermic in the case of cation dyes solution and for MB/MO mixture it was exothermic.

Nitric Acid-Treated Blue Coke-Based Activated Carbon’s Structural Characteristics and Its Application in Hexavalent Chromium-Containing Wastewater Treatment

“…Researchers have been actively developing a number of management techniques, including chemical reduction, adsorption, bioremediation, and electrocoagulation, to reduce the pollution caused by Cr (VI) [7]. Among these, the adsorption method has drawn a lot of interest because of its benefits, which include its high efficiency, adaptability, economy, and ease of use [8]. Cr (VI) removal is aided by carbon-based materials having large surface areas, well-developed pore structures, plenty of functional groups, and superior chemical qualities [9].…”