Dye adsorbed on copolymer, possible specific sorbent for metal ions removal

Muntean, Simona Gabriela; Rădulescu-Grad, Maria Elena; Sfârloagă, Paula

doi:10.1039/c4ra02918f

Cited by 26 publications

(19 citation statements)

References 39 publications

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“…47 As the plot obtained from the q t versus t 1/2 does not pass through the origin, it suggests that the intraparticle diffusion partially controls the rate-limiting step and the adsorption of MG proceeds by film diffusion process as described above. 48−50 The intraparticle diffusion constant ( k id ) is obtained from the plot and increases from LDH A to LDH C and then further decreases for LDH D. The formation of Fe 2 O 3 on the LDH surface may restrict the transportation of MG to the external surface of the adsorbent. Therefore, a higher adsorption capacity ( q e ) is obtained for LDH C (Table 5).…”

Section: Resultsmentioning

confidence: 99%

Kinetics, Isotherm, and Thermodynamic Study for Ultrafast Adsorption of Azo Dye by an Efficient Sorbent: Ternary Mg/(Al + Fe) Layered Double Hydroxides

2018

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The extremely high adsorption efficiency of malachite green (MG) was examined through a series of batch experiments by using Fe 3+ -doped Mg/Al layered double hydroxides (LDHs). The incorporation of iron into Mg/Al LDH with varying Al + Fe molar ratio of 4 + 1, 3 + 2, 2 + 3, and 1 + 4 increased the adsorption capacity with respect to time. The spectral analysis and N 2 sorption studies showed that there was retention of surface morphology in all of the iron-modified LDH samples. The experimental evidences showed that the adsorbent Mg/(Al + Fe) with a molar ratio of 10:2 + 3 had a significant removal, i.e., 99.94% for MG with the initial concentration of 1000 mg L –1 at pH ∼ 9 and at room temperature in 5 min. With further increase in iron loading (at ratio 10:1 + 4), there was a decrease in the removal of MG due to the agglomeration of Fe 2 O 3 on the surface. The adsorption process was best fitted to the Freundlich isotherm followed by the pseudo-second-order model. The standard thermodynamic parameters (Δ H °, Δ S °, and Δ G °) were obtained over the temperature range of 20–50 °C. It was observed that the adsorption of MG onto Mg/(Al + Fe) LDH was spontaneous, exothermic, and enthalpy driven in the physisorption mode. A worthy desorption efficiency was achieved by using ethanol and water, which was more than 90% in the three cycles. Maintaining almost the same removal efficiency of MG even after three cycles indicated Mg/(Al + Fe) LDH as a promising material for wastewater treatment. This work was anticipated to open up new possibilities in dealing with anionic dye pollutants.

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Section: Resultsmentioning

confidence: 99%

Kinetics, Isotherm, and Thermodynamic Study for Ultrafast Adsorption of Azo Dye by an Efficient Sorbent: Ternary Mg/(Al + Fe) Layered Double Hydroxides

2018

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“…A plot of q e versus t 1/2 is usually indicative of the multistep-controlling processes of adsorption. [63][64][65] Thus a multi-step process is involved. It is, however, assumed that the process is controlled by two or more steps if a linear plot which does not pass through the origin is obtained.…”

Section: Batch Adsorption Experimentsmentioning

confidence: 99%

Effectiveness of carbon nanotube–cobalt ferrite nanocomposites for the adsorption of rhodamine B from aqueous solutions

et al. 2015

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The efficiency of adsorption of rhodamine B (RhB) from aqueous solution was investigated through a series of batch experiments by using cobalt ferrite nanoparticles (CoFe 2 O 4 ), acid-functionalized multiwalled carbon nanotubes (MWCNT-COOH) and carbon nanotube-cobalt ferrite nanocomposites. The adsorption capacity was evaluated as a function of pH, contact time, adsorbent dose, dye concentration and temperature. The effect of increasing the percentage of MWCNT-COOH in the nanocomposites was also studied. The adsorption capacity was lowest in CoFe 2 O 4 (5.165 mg g À1 ) and highest with MWCNT-COOH (42.68 mg g À1 ). For the nanocomposites, the adsorption capacity was enhanced with an increase in the amount of MWCNT-COOH. The optimum pH for adsorption was observed at 7 at which equilibrium was reached after 360 min. The kinetics of adsorption was fitted to the pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion models. The results showed that the pseudo-second order model best described the data as reflected in the lowest value for the sum of squared residuals. Among the various adsorption isotherms tested, the Langmuir isotherm provided the best fit to the equilibrium data. The thermodynamic parameters, DH , DS and DG , were obtained over a temperature range of 20-45 C. Adsorption was spontaneous, endothermic and entropy-driven, except for one of the doped nanocomposites for which adsorption was exothermic. A good desorption of RhB from the loaded adsorbents was obtained by using either acetone or ethanol with a desorption efficiency in the range of 62-95%.

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“…This can be explained by a large number of active centers at the beginning of adsorption and saturation of these centers on the surface of the adsorbent with achieving equilibrium. The necessary time for reaching the equilibrium increases with increasing the concentration due to the fact that adsorption involves film diffusion and internal diffusion [29]. The surface diffusion is rapid but the pore diffusion is slower, and the rate of diffusion in the internal adsorption sites decreased with increasing the initial dye concentration.…”

Section: Effect Of Initial Dye Concentration and Contact Timementioning

confidence: 99%

Removal of Colored Organic Pollutants from Wastewaters by Magnetite/Carbon Nanocomposites: Single and Binary Systems

Muntean

Nistor

Muntean

et al. 2018

Journal of Chemistry

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This work develops a methodology for selective removal of industrial dyes from wastewaters using adsorption technology based on magnetic adsorbents. The magnetic nanoparticles embedded within a matrix of activated carbon were tested as adsorbents for removal of industrial dyes from aqueous solutions. The effects of four independent variables, solution pH, initial concentration of pollutant, adsorbent dose, contact time, and their interactions on the adsorption capacity of the nanocomposite were investigated in order to optimize the process. The removal efficiency of pollutants depends on solution pH and increases with increasing the carbon content, with initial concentration of the pollutants, the temperature, and the dose of magnetite/carbon nanocomposites. Pseudo-second-order kinetic model was fitted to the kinetic data, and adsorption isotherm analysis and thermodynamics were used to elucidate the adsorption mechanism. The maximum adsorption capacities were 223.82 mg g −1 for Nylosan Blue, 114.68 mg g −1for Chromazurol S, and 286.91 mg g −1 for Basic Red 2. The regeneration and reuse of the sorbent were evaluated in seven adsorption/desorption cycles. The optimum conditions obtained for individual adsorption were selected as starting conditions for simultaneous adsorption of dyes. In binary systems, in normal conditions, selectivity decreases in the order: Red Basic 2 > Nylosan Blue > Chromazurol S.

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Dye adsorbed on copolymer, possible specific sorbent for metal ions removal

Abstract: The efficiency of styrene-divinylbenzene functionalized with trimethylamonium groups as sorbent for the direct dye removal from aqueous solutions was investigated.

Cited by 26 publications

References 39 publications

Kinetics, Isotherm, and Thermodynamic Study for Ultrafast Adsorption of Azo Dye by an Efficient Sorbent: Ternary Mg/(Al + Fe) Layered Double Hydroxides

Kinetics, Isotherm, and Thermodynamic Study for Ultrafast Adsorption of Azo Dye by an Efficient Sorbent: Ternary Mg/(Al + Fe) Layered Double Hydroxides

Effectiveness of carbon nanotube–cobalt ferrite nanocomposites for the adsorption of rhodamine B from aqueous solutions

Removal of Colored Organic Pollutants from Wastewaters by Magnetite/Carbon Nanocomposites: Single and Binary Systems

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