Sürdürülebilir Kalkınma Amaçları
Yazarlar
Yayınlar
- 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 Erişim2017Scopus SJRQ2Rapid malachite green removal from aqueous solution by natural zeolite: Process optimization by response surface methodology
Tanyol, Mehtap
In this study, malachite green removal from aqueous solutions by natural zeolite was investigated. The interaction between zeolite and malachite green was determined by SEM/EDX and FTIR. The parameters like adsorbent dosage (0.1–1 mg/100 mL), initial malachite green concentration (40–200 mg/L) and the contact time (10–600 s) were optimized using the central composite design of response surface methodology. Maximum removal yield (99.70%) was obtained at an adsorbent dosage of 0.68 mg/100 mL, an initial malachite green concentration of 79.02 mg/L, and at 414 s contact time. The equilibrium process complied better with the Langmuir isotherm model, which exhibits a single layer adsorption, when compared with the Freundlich isotherm model. Adsorption kinetics followed the pseudo-second-order type kinetic and intra-particle diffusion played an important role onto adsorption mechanism of malachite green. The findings of this study demonstrated that zeolite which is found abundant on earth as a cheap and efficient adsorbent could be used for rapid malachite green adsorption from aqueous solutions.
AtıfScopus12WoS11OpenAlex13
İncele - MakaleYalnız künye2015Scopus SJRQ2Removal of Phosphate from Aqueous Solutions by Chemical- and Thermal-Modified Bentonite Clay
Tanyol, Mehtap; Yonten, Vahap; Demir, Veysel
The study investigated phosphate adsorption from aqueous solutions using chemical- and thermal-modified bentonite in batch system. The adsorbent was characterized by SEM, BET, and FTIR spectroscopy. Contact time, beginning phosphate concentration, pH of the solution, and the effects of the temperature on phosphate adsorption capacity were determined by a series of experimental studies. In a wide pH range (3-10), high phosphate removal yields were obtained (between 94.23 and 92.26 %), and with the increase in temperature (from 25 to 45 degrees C), phosphate removal increased. Langmuir and Freundlich isotherms were used to determine the sorption equilibrium, and the results demonstrated that equilibriumdata displayed better adjustment to Langmuir isotherm than the Freundlich isotherm. Phosphate sorption capacity, calculated using Langmuir equation, is 20.37 mg g(-1) at 45 degrees C temperature and pH 3. Mass transfer and kinetic models were applied to empirical findings to determine the mechanism of adsorption and the potential steps that control the reaction rate. Both external mass transfer and intra-particle diffusion played a significant role on the adsorption mechanism of phosphate, and adsorption kinetics followed the pseudo-second-order-type kinetic. Furthermore, thermodynamic parameters (Delta H degrees, Delta G degrees, Delta S degrees) which reveal that phosphate adsorption occur spontaneously and in endothermic nature were determined. The results of this study support that bentonite, which is found abundant in nature and modified as an inexpensive and effective adsorbent, could be used for phosphate removal from aqueous solutions.
AtıfWoS26OpenAlex27İncele