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- MakaleYalnız künye2026Scopus SJRQ2Adsorption of Reactive Red 120 dye from aqueous solutions using sepiolite clay with a channel-structured morphology: Mechanism, kinetics, isotherm, and thermodynamic studies
Fırat, Tülay
The effective treatment of dye-containing wastewater remains a major environmental challenge due to the high stability and solubility of reactive dyes. In this study, the adsorption behavior of Reactive Red 120 (RR120), an anionic reactive azo dye, from aqueous solutions was investigated using natural sepiolite clay possessing a channel-structured morphology. Batch adsorption experiments were performed to evaluate the effects of contact time (1–200 min), initial dye concentration (50–500 mg L−1), adsorbent dosage (0.1–1.5 g), solution pH (2–10), and temperature (25–50°C). The adsorption equilibrium was reached within approximately 75 min. The Langmuir isotherm provided the best fit to the equilibrium data, yielding a maximum monolayer adsorption capacity of 168.4 mg g−1 at 298 K. Thermodynamic analysis revealed that the adsorption process was spontaneous and endothermic, with an activation energy of 32.41 kJ mol−1. Adsorption kinetics were analyzed using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models, while equilibrium data were evaluated using Langmuir, Freundlich, and Temkin isotherm models. The kinetic data were best described by the pseudo-second-order model, while thermodynamic analysis revealed that the adsorption process was spontaneous and endothermic. FTIR and XRD analyses further supported the important role of the channel-structured framework of sepiolite in RR120 adsorption. Unlike many clay-based adsorbents that require chemical modification, natural sepiolite exhibited high adsorption performance due to its intrinsic fibrous morphology, nano-channel structure, and high surface area. These findings demonstrate that natural sepiolite is a promising, low-cost, and sustainable adsorbent for the treatment of dye-contaminated wastewater.
- MakaleAçık Erişim2018Scopus SJRQ2Comparative Adsorption of Different Dyes from Aqueous Solutions onto Polymer Prepared by ROP: Kinetic, Equilibrium and Thermodynamic Studies
Torğut, Gülben; Demirelli, Kadir
Poly(1,2-epoxy-3-phenoxy)propane was synthesized by ring-opening polymerization using Sn (Oct) 2 as a catalyst and benzyl alcohol as an initiator. Homopolymer’s epoxy type was acylated with chloroacetyl chloride firstly and then modified with the diethanol amine. The polymers were characterized by FT-IR and 1H - NMR. Dye adsorption properties of poly(2-phenoxy ethyl [bis(2-hydroxy ethyl)amino]acetate) were investigated by using bromocresol green (BCG), alizarin yellow (AY) and methylene blue (MB). Amounts of dye holding polymers at different times were calculated and plotted as a function of time. According to the removal results, all of the dyes reach its highest efficiency at 90 min. The effect of pH on adsorption of dyes was studied in the pH range of 2–11. Kinetic models known as pseudo-first order and pseudo-second order were used to analyze the mechanism of adsorption, and the results indicated an adsorption kinetic compatible with the pseudo-second order. The Langmuir and Freundlich isotherms were utilized to explain the adsorption equilibrium, and when it was compared with each other, it was revealed that the Langmuir isotherm model was better than Freundlich isotherm. The maximum adsorption capacities of BCG, AY and MB were 52.63, 15.87 and 31.25 mg/g, respectively. Furthermore, thermodynamic properties (Δ H∘, Δ S∘, Δ G∘) of modified polymer were investigated for the three dyes. According to the thermodynamic parameters, the adsorption of the dyes occurred spontaneously and was endothermic. The results of this study support that novel polymer, an inexpensive and effective adsorbent, could be used for dye removal from aqueous solutions.
AtıfScopus20WoS16OpenAlex24
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