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Iron-modified activated carbon derived from agro-waste for enhanced dye removal from aqueous solutions

2021; Elsevier BV; Volume: 7; Issue: 6 Linguagem: Inglês

10.1016/j.heliyon.2021.e07191

2405-8440

Fateme Barjasteh-Askari, Mojtaba Davoudi, Maryam Dolatabadi, Saeid Ahmadzadeh,

Chromium effects and bioremediation

Finding a cost-effective adsorbent can be an obstacle to large-scale applications of adsorption. This study used an efficient activated carbon adsorbent based on agro-waste for dye removal.Pistachio shells as abundant local agro-wastes were used to prepare activated carbon. Then, it was modified with iron to improve its characteristics. Acid red 14 was used as a model dye in various conditions of adsorption (AR14 concentration 20-150 mg L-1, pH 3-10, adsorbent dosage 0.1-0.3 g L-1, and contact time 5-60 min).A mesoporous adsorbent was prepared from pistachio shells with 811.57 m2 g-1 surface area and 0.654 cm3 g-1 pore volume. Iron modification enhanced the characteristics of activated carbon (surface area by 33.3% and pore volume by 64.1%). Adsorption experiments showed the high effectiveness of iron-modified activated carbon for AR14 removal (>99%, >516 mg g-1). The adsorption followed the pseudo-second kinetic model (k = 0.0005 g mg-1 min-1) and the Freundlich isotherm model (Kf = 152.87, n = 4.61). Besides, the reaction occurred spontaneously (ΔG0 = -36.65 to -41.12 kJ mol-1) and was exothermic (ΔH0 = -41.86 kJ mol-1 and ΔS0 = -3.34 J mol-1 K-1).Iron-modified activated carbon derived from pistachio shells could be cost-effective for the treatment of industrial wastewater containing dyes.