scholarly journals Study on the adsorption of Rhodamine B on MoS2/RGO composite

2020 ◽  
Vol 9 (4) ◽  
pp. 57-63
Author(s):  
Trang Phan Thi Thuy ◽  
Tam Truong Thanh ◽  
Vien Vo ◽  
Lien Nguyen Hong

In this study, MoS2/RGO (reduced graphene oxide) composite material was synthesized and tested for adsorption of RhB in water. The adsorption studies were carried out at room temperature and the effects of pH, amount of adsorbents, concentration of adsorbate and time of adsorption on the adsorption were measured. In addition, the dynamics of the adsorption process was also investigated. The results showed that the MoS2/RGO composite displayed toward RhB with maximum adsorption capacity reaching q = 57.79 mg/g at pH = 3.54 and the adsorption process follows the Langmuir adsorption isotherm with the pseudo-second-order model. Findings from this research indicated that the graphene based semiconductor MoS2/RGO composite could be considered a promising adsorbent for removal of organic dyes from waste waters.

2018 ◽  
Vol 56 (1A) ◽  
pp. 25
Author(s):  
Nguyen Quang Dat

In this paper, we present a recent study in the adsorption of uranium from an aquatic environment by reduced graphene oxide - Cu0.5Ni0.5Fe2O4 ferrite – polyaniline (RGO/CNF/PANI) composite. Uranium concentration was carried out by batch techniques. The effect of pH, contact time, concentration of equilibrium state and reusability on uranium adsorption capacity have been studied. The adsorption process was accomplished within 240 min and could be well described by the pseudo-second-order model. The adsorption isotherm agrees well with the Langmuir model, having a maximum adsorption capacity of 2000 mg/g, at pH = 5 and 25 oC. The RGO/CNF/PANI materials could be a promising absorbent for removing U (VI) in aqueous solution because of their high adsorption capacity and convenient magnetic separation. 


Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2218 ◽  
Author(s):  
Carlos Grande-Tovar ◽  
William Vallejo ◽  
Fabio Zuluaga

In this work, we synthesized chitosan grafted-polyacrylic acid (CS-g-PA) through surface-initiated atom transfer radical polymerization (SI-ATRP). We also studied the adsorption process of copper and lead ions onto the CS-g-PA surface. Adsorption equilibrium studies indicated that pH 4.0 was the best pH for the adsorption process and the maximum adsorption capacity over CS-g-PA for Pb2+ ions was 98 mg·g−1 and for Cu2+ it was 164 mg·g−1, while for chitosan alone (CS), the Pb2+ adsorption capacity was only 14.8 mg·g−1 and for Cu2+ it was 140 mg·g−1. Furthermore, the adsorption studies indicated that Langmuir model describes all the experimental data and besides, pseudo-second-order model was suitable to describe kinetic results for the adsorption process, demonstrating a larger kinetic constant of the process was larger for Pb2+ than Cu2+. Compared to other adsorbents reported, CS-g-PA had comparable or even superior adsorbent capacity and besides, all these results suggest that the new CS-g-PA polymers had potential as an adsorbent for hazardous and toxic metal ions produced by different industries.


2018 ◽  
Vol 77 (5) ◽  
pp. 1313-1323 ◽  
Author(s):  
Jianjun Zhou ◽  
Xionghui Ji ◽  
Xiaohui Zhou ◽  
Jialin Ren ◽  
Yaochi Liu

Abstract A novel magnetic bio-adsorbent (MCIA) was developed, characterized and tested for its Cd(II) removal from aqueous solution. MCIA could be easily separated from the solution after equilibrium adsorption due to its super-paramagnetic property. The functional and magnetic bio-material was an attractive adsorbent for the removal of Cd(II) from aqueous solution owing to the abundant adsorption sites, amino-group and oxygen-containing groups on the surface of Cyclosorus interruptus. The experimental results indicated that the MCIA exhibited excellent adsorption ability and the adsorption process was spontaneous and endothermic. The adsorption isotherm was consistent with the Langmuir model. The adsorption kinetic fitted the pseudo-second-order model very well. The maximum adsorption capacity of Cd(II) onto MCIA was 40.8, 49.4, 54.6 and 56.6 mg/g at 293, 303, 313 and 323 K, respectively. And the MCIA exhibited an excellent reusability and impressive regeneration. Therefore, MCIA could serve as a sustainable, efficient and low-cost magnetic adsorbent for Cd(II) removal from aqueous solution.


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Mashael Alshabanat ◽  
Ghadah Alsenani ◽  
Rasmiah Almufarij

The adsorption of crystal violet (CV) onto date palm fibers (DPFs) was examined in aqueous solution at 25°C. The experimental maximum adsorption capacity value was0.66×10−6. Langmuir, Freundlich, Elovich and Temkin models were applied to describe the equilibrium isotherms. The influence of pH and temperature on dye removal was evaluated. The percentage removal of CV dye by adsorption onto DPF at different pH and temperatures showed that these factors play a role in the adsorption process. Thermodynamic analysis was performed, and the Gibbs free energyΔGο, enthalpy changeΔHο, and entropyΔSοwere calculated. The negative values ofΔGοindicate spontaneous adsorption. The negative value ofΔHοindicates that the interaction between CV and DPF is exothermic, and the positive value ofΔSοindicates good affinity between DPF and CV. The kinetic data were fitted to a pseudo-second-order model.


2021 ◽  
Vol 16 (2) ◽  
pp. 566-581
Author(s):  
B. Jagadeeswara Reddy ◽  
Sneha Latha Pala ◽  
Wondwosen Kebede Biftu ◽  
M. Suneetha ◽  
Kunta Ravindhranath

Abstract Sorbents derived from stem powders of Feronia limonia (FLSP), Amorphophallus paeoniifolius (APSP) and Pumpkin (Cucurbitapepo) (PSP) plants are investigated for the removal of Cu2+ ions from polluted water by adopting batch methods of extraction. Extraction conditions are optimized for the effective removal of Cu2+ ions. High sorption capacities are observed: 175.5 mg/g for FLSP; 140.4 mg/g for APSP; 130.0 mg/g for PSP. Effective pH ranges are: 5 to 10 for FLSP; 6 to 10 for APSP and 7 to 10 for PSP. The three spent adsorbents can be regenerated and used. Thermodynamic parameters indicate that the adsorption process is spontaneous, endothermic and have positive change in entropy values. As ΔH values are more than 25.0 kJ/mole, the adsorption may be due to surface complex formation between Cu2+ ions and functional groups of the adsorbents viz., -OH, -COOH etc. in the effective pH ranges. The good adsorption behaviour of FLSP even in acidic pHs may be due to the ion-exchange of Cu2+ ions for H+ ions of the functional groups of the adsorbent. The Langmuir adsorption isotherm and pseudo second-order model describe well the adsorption process. The sorbents are effectively applied to treat effluents from Cu-based industries and polluted lake water.


2019 ◽  
Vol 79 (1) ◽  
pp. 126-136 ◽  
Author(s):  
Yan Chen ◽  
Wei Chen ◽  
Quanzhou Chen ◽  
Changhong Peng ◽  
Dewen He ◽  
...  

Abstract In this study, a novel poly ligand exchanger-Zn(II)-loaded resin was designed to effectively remove ammonia-nitrogen (NH3-N) from wastewater. The surface morphology and structure of the Zn-loaded resin were characterized using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and Fourier transform infrared spectroscopy (FTIR), respectively. SEM shows the surfaces of the Zn(II)-loaded resin were rough and nonporous and EDS demonstrated that Zn2+ was loaded onto the resin successfully. In addition, the combination form of Zn(II) with NH3-N adsorption reagent was revealed by FTIR spectra; the complex could be R-N-R-O-Zn-O-R-N-R and R-N-R-(O-Zn)2. The kinetics and equilibrium of the NH3-N adsorption onto the Zn(II)-loaded resin has been investigated. The effects of pH, reaction time, and temperature on NH3-N removal from wastewater by Zn(II)-loaded resin were investigated, and the results showed that the maximum adsorption capacity reached 38.55 mg/g at pH 9.54 at 298 K in 240 min. The adsorption ability of the modified resin decreased with an increase in temperature. Moreover, the NH3-N adsorption followed a pseudo-second-order kinetic process. The kinetic data demonstrated that the adsorption process might be limited by a variety of mechanisms. The study can provide the scientific foundation for the extensive application of a novel poly ligand exchanger-Zn(II)-loaded resin to remove NH3-N from wastewater.


2020 ◽  
Vol 7 (3) ◽  
pp. 191811
Author(s):  
Yazhen Wang ◽  
Shuang Li ◽  
Liqun Ma ◽  
Shaobo Dong ◽  
Li Liu

Corn stalk was used as the initial material to prepare a corn stalk matrix-g-polyacrylonitrile-based adsorbent. At first, the corn stalk was treated with potassium hydroxide and nitric acid to obtain the corn stalk-based cellulose (CS), and then the CS was modified by 2-bromoisobutyrylbromide (2-BiBBr) to prepare a macroinitiator. After that, polyacrylonitrile (PAN) was grafted onto the macroinitiator by single-electron transfer living radical polymerization (SET-LRP). A novel adsorbent AO CS-g-PAN was, therefore, obtained by introducing amidoxime groups onto the CS-g-PAN with hydroxylamine hydrochloride (NH 2 OH · HCl). FTIR, SEM and XPS were applied to characterize the structure of AO CS-g-PAN. The adsorbent was then employed to remove Pb(II) and Cu(II), and it exhibited a predominant adsorption performance on Pb(II) and Cu(II). The effect of parameters, such as temperature, adsorption time, pH and the initial concentration of metal ions on adsorption capacity, were examined in detail during its application. Results suggest that the maximum adsorption capacity of Pb(II) and Cu(II) was 231.84 mg g –1 and 94.72 mg g −1 , and the corresponding removal efficiency was 72.03% and 63%, respectively. The pseudo-second order model was more suitable to depict the adsorption process. And the adsorption isotherm of Cu(II) accorded with the Langmuir model, while the Pb(II) conformed better to the Freundlich isotherm model.


2015 ◽  
Vol 72 (8) ◽  
pp. 1437-1445
Author(s):  
Ting Li ◽  
Chencen Guo ◽  
Tonghui Xie ◽  
Chengxianyi Zhou ◽  
Yongkui Zhang

A novel anion exchange resin, quaternary ammonium–Chlorella vulgaris (QACV), was prepared by introducing quaternary ammonium groups onto dried Chlorella vulgaris as base material. Degrees of epoxy, amine and quaternary ammonium groups of QACV were measured. Water retention, optical microscopy, and Fourier transform infrared spectrometry were used to characterize QAVC. The adsorption behavior of QACV towards Ag(CN)2− in different conditions was studied carefully. The results showed that QAVC was efficient to adsorb Ag(CN)2− at pH 9–11, and adsorption equilibrium was almost reached in 30 min. Both kinetics and isotherm parameters in the adsorption process were obtained. The data indicated that the pseudo-second-order model provided a good correlation for adsorption of Ag(CN)2− on QACV and the calculated rate constant of the adsorption was 3.51 g/(mmol min). The equilibrium data fitted well in the Langmuir isotherm and the estimated maximum adsorption capacity qm was 1.96 mmol/g. The dimensionless separation factor RL was between 0 and 1, suggesting that the adsorption process of Ag(CN)2− using QACV was favorable. The QACV could be used successively three times without significantly affecting its adsorption efficiency. Chlorella vulgaris was a potential base material to be modified with quaternary ammonium groups to prepare an adsorbent for adsorption of Ag(CN)2−.


2021 ◽  
Vol 55 (9-10) ◽  
pp. 1131-1142
Author(s):  
BENGÜ ERTAN ◽  

Stinging nettle was used as lignocellulosic adsorbent for the removal of cationic dye – malachite green (MG), and anionic dye – Congo red (CR), from aqueous solution, without any chemical pretreatment. The adsorption equilibrium data fitted well with the Langmuir model for the adsorption of both dyes, with the calculated maximum adsorption capacity of 270.27 mgg-1 and 172.14 mgg-1 for MG and CR, respectively. The adsorption process was controlled by the pseudo-second-order model in the adsorption of MG and by the pseudo-first-order model in the adsorption of CR. The thermodynamics modelling displayed that the process was spontaneous and endothermic. The π–π electron–donor interaction, hydrogen bonds and pore diffusion may also be effective, besides electrostatic interaction between the adsorbate and the adsorbent in the mechanism of MG and CR uptake.


2012 ◽  
Vol 209-211 ◽  
pp. 2005-2008 ◽  
Author(s):  
Fang Juan Zhang ◽  
Hua Yong Zhang ◽  
Lu Yi Zhang

The feasibility of coal gangue as an adsorbent for phosphate removal from wastewater was investigated. The results showed that the equilibrium data were well fit to Langmuir isotherm model and the maximum adsorption capacity calculated was 2.49 mg/g at 25°C. The adsorption process followed pseudo-second order model. And the practical waste water experiment indecated that the phosphate concentration of real sewage decreased from 0.625mg/L to 0.121mg/L. These results suggested that coal gangue can be used as an adsorbent to removal phosphate from wastewater.


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