Adsorption of an Anionic Dye from Aqueous Solution over a Treated Clay

MARIA C. AVILA; ILEANA D. LICK; MARIA LUCIA RUIZ; NORA A. COMELLI

Groundwater for Sustainable Development.

Elsevier

Año: 2021

2352-801X

The presence of synthetic dyes in water causes serious environmental issues due to the poor water quality, toxicity to the environment and human carcinogenic effects. Adsorption has progressively become an economical and feasible method for dye wastewater decontamination. Clayminerals are an interesting alternative for removing colorants from colored aqueous solutions because they are inexpensive, easy to extract and handle, and non-toxic. In this work, a bentonitetreated with H2SO4 is used to adsorb an azoderivative dye such as methyl orange (MO). Thephysicochemical properties of the solids were evaluated through X-ray powder diffraction (XRD),Brunauer Emmett Teller surface area analysis (BET), Scanning electron microscopy coupled withEnergy dispersive spectroscopy (SEM-EDS), and Fourier transform infrared spectroscopy (FTIR).The initial dye concentration, adsorbent mass, contact time, temperature and pH influence theadsorption capacity. Acid modification of the clay increased its capacity to adsorb MO. For a concentration of 200 mg/L MO, an adsorption capacity of 125 mg/g was achieved. The adsorptionprocess follows the pseudo second-order kinetic model. The thermodynamic study indicates thatthe adsorption is spontaneous and exothermic. The adsorption isotherm is best fitted to the Freundlich mathematical model. The results obtained show that, after receiving an acid treatment,clay can be effectively used to remove MO in aqueous solution.