scholarly journals Taguchi optimization approach for metronidazole removal from aqueous solutions by using graphene oxide functionalized β-cyclodextrin/Ag nanocomposite

2018 ◽  
Vol 2017 (1) ◽  
pp. 36-47 ◽  
Author(s):  
Neamatollah Jafarzadeh ◽  
Hamideh Rezazadeh ◽  
Zahra Ramezani ◽  
Sahand Jorfi ◽  
Mehdi Ahmadi ◽  
...  
Keyword(s):  
Experimental Data ◽  
Graphene Oxide ◽  
Ionic Strength ◽  
Contact Time ◽  
Carbon Adsorbents ◽  
Isotherm Models ◽  
Optimization Approach ◽  
Order Kinetic ◽  
Solution Ph ◽  
Taguchi Optimization

Abstract Metronidazole (MNZ) is a major threat to the ecosystems and human health, due to its toxicity and carcinogenic nature. The main aim of this study was to evaluate the efficiency of graphene oxide functionalized β-cyclodextrin/Ag nanocomposite (GO/β-CD/Ag) for MNZ removal from aqueous solution. The effect of operational parameters such as solution pH (2–5), adsorbent dosages (0.2–1 g/L), contact time (10–80 min), initial MNZ concentrations (0.25–10 mg/L) and ionic strength (0.001–0.1 mol/L) was studied using Taguchi experimental design. The maximum removal efficiency of 93.5% was observed for optimum conditions. The optimum values of contact time, the initial MNZ concentration, the ionic strength, the adsorbent dosage and solution pH were found to be 20 min, 0.25 ppm, 0.01 mol/L, 0.4 g/L and 2, respectively. Freundlich and Dubinin–Radushkevich isotherm models were best-fitted with experimental data. Pseudo-first order and type 1 pseudo-second order kinetic models showed the maximum correlation with the experimental data. Adsorption experiments with real samples indicated that the adsorptive removal of MNZ from a hospital wastewater was 72%. Desorption studies showed maximum recovery of GO/β-CD/Ag nanocomposite during three cycles. According to the obtained results, it can be concluded that the application of carbon adsorbents such as GO/β-CD/Ag can be considered an efficient method for final treatment of effluents containing antibiotics.

scholarly journals Sorption of Cd2+ and Pb2+ on Aragonite Synthesized from Eggshell

2020 ◽  
Vol 12 (3) ◽  
pp. 1174 ◽  
Author(s):  
Lulit Habte ◽  
Natnael Shiferaw ◽  
Mohd Danish Khan ◽  
Thenepalli Thriveni ◽  
Ji Whan Ahn
Keyword(s):  
Experimental Data ◽  
Synthetic Wastewater ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Solution Ph ◽  
Surface Precipitation ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
High Sorption ◽  
Pseudo Second Order

In the present work, waste eggshells were used as a precursor for the synthesis of aragonite crystals through the wet carbonation method. Cadmium (Cd2+) and lead (Pb2+) were removed by the synthesized aragonite from synthetic wastewater. The influence of initial solution pH, contact time, Cd2+ and Pb2+ concentration, and sorbent dosage were evaluated. The major sorption was observed in the first 100 mins and 360 mins for Pb2+and Cd2+ respectively reaching sorption equilibrium at 720 mins (12 hr). The sorption capacity toward Pb2+ was much higher than toward Cd2+. Both heavy metals displayed high sorption capacities at initial pH 6. The pseudo-second-order kinetic model fits well with the experimental data with a higher correlation coefficient R2. Two isotherm models were also evaluated for the best fit with the experimental data obtained. Langmuir isotherm best fits the sorption of the metals on aragonite synthesized from eggshells. X-ray diffraction (XRD) and Scanning electron microscopy (SEM) results of sorbent after sorption showed that the mechanism of sorption was dominated by surface precipitation. Therefore, aragonite crystals synthesized from waste eggshells can be a potential substitute source for the removal of Cd2+ and Pb2+ from contaminated water.

scholarly journals Equilibrium, Kinetics, and Thermodynamics of the Biosorption of Zn(II) from Aqueous Solution Using Powdered Cow Hooves

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Ilesanmi Osasona ◽  
Olubode O. Ajayi ◽  
Albert O. Adebayo
Keyword(s):  
Aqueous Solution ◽  
Contact Time ◽  
Kinetic Equations ◽  
Mesh Size ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Solution Ph ◽  
Equilibrium Studies ◽  
Biosorption Process ◽  
Increase With Increase

The capability of cow hoof (CH) to remove Zn(II) from aqueous solution under the influence of sorbent size, solution pH, contact time, and sorbent dosage was investigated through batch studies. Equilibrium studies were conducted at three different temperatures (298, 308, and 318 K) by contacting different concentrations of Zn(II) solution with a known weight of cow hoof. The biosorption of Zn onto cow hoof was found to increase with increase in the mass of sorbent used while the biosorption efficiency was found to decrease with increase in sorbent particle size. The optimum conditions of pH 4 and contact time of 60 minutes were required for maximum removal of Zn(II) by cow hoof (mesh size 212 µm). The equilibrium data were modelled using Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm models. The data were best fitted by Langmuir model. The kinetic data were analysed using Lagergren kinetic equations and these were well fitted by the pseudo-second-order kinetic model. The thermodynamic parameters showed that the biosorption process was feasible, spontaneous, and endothermic.

scholarly journals Synthesis and Characterisation of Graphene Oxide-Silica-Chitosan for Eliminating the Pb(II) from Aqueous Solution

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1922
Author(s):  
Sepehr Azizkhani ◽  
Ebrahim Mahmoudi ◽  
Norhafizah Abdullah ◽  
Mohd Halim Shah Ismail ◽  
Abdul Wahab Mohammad ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Contact Time ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Removal Capacity ◽  
Transmission Electron ◽  
Low Concentrations ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Ft Ir

Heavy metal ions have a toxic and negative influences on the environment and human health even at low concentrations and need to be removed from wastewater. Chitosan and graphene oxide are suitable nano plate adsorbents with high adsorption potential because of their π-π interaction, and they are available functional groups that interact with other elements. In this study, graphene oxide was coated with silica to enhance the hydrophilicity of the adsorbent. Subsequently, the adsorbent was functionalised by various amounts of chitosan to improve the Pb(II) removal. The adsorbent was analysed using transmission electron microscopy (TEM), Raman, Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and mapping analysis techniques. An investigation of the influences of the initial concentration of Pb(II), pH and contact time were included to obtain the optimum amount of adsorption. The range of the initial Pb(II) concentration studied was from 10 to 120 mg/L. The pH factor ranged from 3 to 8 with contact time from 0 to 140 min. Freundlich, Temkin and Langmuir isotherm models were fit to the results, and a pseudo-second-order kinetic model was found to provide a good fit as well. The maximum Pb(II) removal capacity achieved was 256.41 (+/− 4%) mg/g based on Langmuir isotherms.

scholarly journals Adsorption of Chromium(VI) onto Freshwater Snail Shell-Derived Biosorbent from Aqueous Solutions: Equilibrium, Kinetics, and Thermodynamics

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Xuan Hoa Vu ◽  
Lan Huong Nguyen ◽  
Huu Tap Van ◽  
Dinh Vinh Nguyen ◽  
Thu Huong Nguyen ◽  
...  
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Contact Time ◽  
Low Cost ◽  
Freshwater Snail ◽  
Isotherm Models ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Adsorption Mechanisms

In this study, freshwater snail shells (FSSs) containing CaCO3 were used as a low-cost biosorbent for removing Cr(VI) from aqueous solutions. The characteristics of FSS and mechanism of Cr(VI) adsorption onto FSS were investigated. The FSS biosorbent was characterized using nitrogen adsorption/desorption isotherm, X-ray diffraction, scanning electron microscopy with energy dispersive spectroscopy, and Fourier transform infrared spectroscopy. The adsorption mechanism was determined by conducting various batch adsorption experiments along with fitting experimental data with various adsorption models. Batch adsorption experiments were conducted as a function of solution pH, contact time, biosorbent dose, and initial Cr(VI) concentration. Results indicated that pH = 2, a contact time of 120 min, and an initial Cr(VI) concentration of 30 mg/L at 20°C were the best conditions for adsorption of Cr(VI) onto FSS. The Cr(VI) adsorption onto FSS decreased with an increase in temperature from 20 to 40°C. The obtained maximum adsorption capacity was 8.85 mg/g for 2 g/L of FSS dose with 30 mg/L of initial Cr(VI) at 20°C. The adsorption equilibrium data fit well with the Sips and Langmuir isotherm models at 20°C with a high R2 of 0.981 and 0.975, respectively. Also, a good correlation between the experimental data and the pseudo-second-order model was achieved, with the highest R2 of 0.995 at 20°C. The adsorption mechanisms were electrostatic interaction and ion exchange. Simultaneously, this mechanism was also controlled by film diffusion. The Cr(VI) adsorption process was irreversible, spontaneous (−∆G°), exothermic (∆H° is negative), and less random (∆S° is negative). In conclusion, freshwater snail shells have the potential as a renewable adsorbent to remove toxic metals from wastewater.

scholarly journals Multi-Component Adsorption of Benzene, Toluene, Ethylbenzene, and Xylene from Aqueous Solutions by Montmorillonite Modified with Tetradecyl Trimethyl Ammonium Bromide

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
H. Nourmoradi ◽  
Mehdi Khiadani ◽  
M. Nikaeen
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Structural Changes ◽  
Freundlich Isotherm ◽  
Isotherm Models ◽  
Ammonium Bromide ◽  
Order Kinetic ◽  
Multicomponent Adsorption ◽  
Benzene Toluene ◽  
Kinetic And Isotherm Models

Multicomponent adsorption of benzene, toluene, ethylbenzene, and xylene (BTEX) was assessed in aqueous solutions by montmorillonite modified with tetradecyl trimethyl ammonium bromide (TTAB-Mt). Batch experiments were conducted to determine the influences of parameters including loading rates of surfactant, contact time, pH, adsorbate concentration, and temperature on the adsorption efficiency. Scanning electron microscope (SEM) and X-ray diffractometer (XRD) were used to determine the adsorbent properties. Results showed that the modification of the adsorbent via the surfactant causes structural changes of the adsorbent. It was found that the optimum adsorption condition achieves with the surfactant loading rate of 200% of the cation exchange capacity (CEC) of the adsorbent for a period of 24 h. The sorption of BTEX by TTAB-Mt was in the order ofB<T<E<X. The experimental data were fitted by many kinetic and isotherm models. The results also showed that the pseudo-second-order kinetic model and Freundlich isotherm model could, respectively, be fitted to the experimental data better than other available kinetic and isotherm models. The thermodynamic study indicated that the sorption of BTEX with TTAB-Mt was achieved spontaneously and the adsorption process was endothermic as well as physical in nature. The regeneration results of the adsorbent also showed that the adsorption capacity of adsorbent after one use was 51% to 70% of original TTAB-Mt.

scholarly journals Removal of anionic surfactants by sorption onto Aminated Mesoporous Carbon

2013 ◽  
Vol 19 (3) ◽  
pp. 347-357 ◽  
Author(s):  
S.E. Moradi ◽  
J. Khodaveisy ◽  
R. Dashti
Keyword(s):  
Contact Time ◽  
Mesoporous Carbon ◽  
Anionic Surfactants ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Langmuir Model ◽  
Carbon Adsorbents ◽  
Solution Ph ◽  
Batch Mode ◽  
Ft Ir

Direct and indirect releases of large quantities of surfactants to the environment may result in serious health and environmental problems. Therefore, surfactants should be removed from water before release to the environment or delivery for public use. In the present work, the removal of anionic surfactants, benzene sulfonate (BS), p-toluene sulfonate (TS) and 4-octylbenzene sulfonate (OBS) from water by adsorption onto Amino modified mesoporous carbon (AMC) were studied. The AMC surface chemistry and textural properties was characterized by nitrogen adsorption, XRD and FT-IR analyses. Experiments were conducted in batch mode with the variables such as amount of contact time, solution pH, dose of adsorbent and temperature. Finally, the adsorption isotherms of anionic surfactants on mesoporous carbon adsorbents were in agreement with a Langmuir model. AMC has shown higher anionic surfactants adsorption capacity than the untreated mesoporous carbon, which can explain by strong interaction between anionic surfactant and cationic surface of adsorbent.

scholarly journals Effectiveness of beetroot seeds and H3PO4 activated beetroot seeds for the removal of dyes from aqueous solutions

2017 ◽  
Vol 8 (4) ◽  
pp. 522-531
Author(s):  
A. Machrouhi ◽  
M. Farnane ◽  
A. Elhalil ◽  
R. Elmoubarki ◽  
M. Abdennouri ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Solution Ph ◽  
Experimental Isotherm ◽  
Adsorbent Dosage ◽  
Adsorption Capacities ◽  
Monolayer Adsorption ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Abstract Raw beetroot seeds (BS) and H3PO4 activated beetroot seeds (H3PO4-BS) were evaluate for their effectiveness in removing methylene blue (MB) and malachite green (MG) from aqueous solution. BS were carbonized at 500°C for 2 h, and then impregnated with phosphoric acid (phosphoric acid to BS ratio of 1.5 g/g). The impregnated BS were activated in a tubular vertical furnace at 450°C for 2 h. Batch sorption experiments were carried out under various parameters, such as solution pH, adsorbent dosage, contact time, initial dyes concentration and temperature. The experimental results show that the dye sorption was influenced by solution pH and it was greater in the basic range. The sorption yield increases with an increase in the adsorbent dosage. The equilibrium uptake was increased with an increase in the initial dye concentration in solution. Adsorption kinetic data conformed more to the pseudo-second-order kinetic model. The experimental isotherm data were evaluated by Langmuir, Freundlich, Toth and Dubinin–Radushkevich isotherm models. The Langmuir maximum monolayer adsorption capacities were 61.11 and 74.37 mg/g for MB, 51.31 and 213.01 mg/g for MG, respectively in the case of BS and H3PO4-BS. The thermodynamic parameters are also evaluated and discussed.

scholarly journals Equilibrium, Kinetics, and Thermodynamics of the Removal of Nickel(II) from Aqueous Solution Using Cow Hooves

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
I. Osasona ◽  
O. O. Ajayi ◽  
A. O. Adebayo
Keyword(s):  
Aqueous Solution ◽  
Contact Time ◽  
Room Temperature ◽  
Physical Adsorption ◽  
Low Cost ◽  
Freundlich Isotherm ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Equilibrium Studies ◽  
Equilibrium Data

The feasibility of using powdered cow hooves (CH) for removing Ni2+ from aqueous solution was investigated through batch studies. The study was conducted to determine the effect of pH, adsorbent dosage, contact time, adsorbent particle size, and temperature on the adsorption capacity of CH. Equilibrium studies were conducted using initial concentration of Ni2+ ranging from 15 to 100 mgL−1 at 208, 308, and 318 K, respectively. The results of our investigation at room temperature indicated that maximum adsorption of Ni2+ occurred at pH 7 and contact time of 20 minutes. The thermodynamics of the adsorption of Ni2+ onto CH showed that the process was spontaneous and endothermic. Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm models were used to quantitatively analysed the equilibrium data. The equilibrium data were best fitted by Freundlich isotherm model, while the adsorption kinetics was well described by pseudo-second-order kinetic equation. The mean adsorption energy obtained from the D-R isotherm revealed that the adsorption process was dominated by physical adsorption. Powdered cow hooves could be utilized as a low-cost adsorbent at room temperature under the conditions of pH 7 and a contact time of 20 minutes for the removal of Ni(II) from aqueous solution.

scholarly journals Biosorption of Cr(III) from aqueous solution using an agricultural by-product jute stick powder: Equilibrium and kinetic studies

2018 ◽  
Vol 9 (3) ◽  
pp. 202-212 ◽  
Author(s):  
Mohammad Nasir Uddin ◽  
Jahangir Alam ◽  
Syeda Rahimon Naher
Keyword(s):  
Aqueous Solution ◽  
Contact Time ◽  
Metal Ion ◽  
Water Solution ◽  
Low Cost ◽  
Isotherm Models ◽  
Infrared Spectrometry ◽  
Order Kinetic ◽  
Adsorption Model ◽  
Experimental Conditions

The adsorption capacity of chromium(III) from synthetic waste water solution by a low cost biomaterial, Jute Stick Powder (JSP)was examined. A series of batch experiments were conducted at different pH values, adsorbent dosage and initial chromium concentration to investigate the effects of these experimental conditions. To analyze the metal adsorption on to the JSP, most common adsorption isotherm models were applied. To study the reaction rate, the kinetic and diffusion models were also applied. The morphological structure and variation of functional groups in the JSP before and after adsorption was examined by scanning electron microscope (SEM) and Fourier transform infrared spectrometry (FT-IR). Maximum chromium removal capacities of JSP was 84.34%with corresponding equilibrium uptake 8.4 mg/g from 50 mg/L of synthetic metal solution in 60 minutes of contact time at pH = 6.0 and 28 °C with continuous stirring at 180 rpm. The percent sorption of the biomass decreased with increasing concentration of metal ion but increased with decreasing pH, increasing contact time and adsorbent doses. Data for this study indicated a good correspondence with both isotherms of Langmuir and Freundlich isotherm. The analysis of kinetic indicated that Chromium was consistent with the second-order kinetic adsorption model. The rate of removal of Cr(III) ions from aqueous solution by JSP was found rapid initially within 5-30 minutes and reached in equilibrium in about 40 minutes. The investigation revealed that JSP, a low cost agricultural byproduct, was a potential adsorbent for removal of heavy metal ions from aqueous solution.

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