Valorization of Dairy Sludge in Water Treatment: Assessment of Biosorption of an Industrial Dye (A-BG)

Abstract

Pollution control has become a priority today. Industrial wastewater in general and from the textile and paper industries in particular can contain a variety of organic micro pollutants including dyes. The non treatment of these waters poses a serious problem for the ecosystem. In order to reduce the polluting load of this water, it is advantageous to carry out treatments before it is discharged. Biosorption can be considered as an effective and inexpensive alternative to the various existing technologies for the removal of micro pollutants. Biosorption was studied as a function of initial pH solution, biosorbent dose, biosorbent particle diameter and initial dye ion concentration. These parameters were measured in batch experiments. Equilibrium uptake increased with increasing dye concentration with a maximum sorption capacity of a 178.6 mg g-1. Model equations such as Langmuir and Freundlich isotherms were used to analyze the adsorption equilibrium data and the best fits to the experimental data were provided by the first isotherm model. Scanning electron microscopy and energy-dispersive X-ray (SEM-EDX), Brunauer–Emett–Teller (BET), Fourier transform infrared analyses (FTIR) and microbiological characterisation were also performed to characterize the biosorbent. To describe the adsorption mechanism, kinetic models such as pseudo-second-order and the intra particle diffusion were applied. The proposal study consists of testing in a batch system the ability of a dairy sludge to fix a dye used in the textile industry, A-BG (Astrazon brilliant) in aqueous solution. Dairy sludge was investigated as potential adsorbent for the removal of hazardous cationic dyes.