scholarly journals Adsorptive Removal of Methylene Blue from Aquatic Environments Using Thiourea-Modified Poly(Acrylonitrile-co-Acrylic Acid)

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1734 ◽  
Author(s):  
Abel Adekanmi Adeyi ◽  
Siti Nurul Ain Md Jamil ◽  
Luqman Chuah Abdullah ◽  
Thomas Shean Yaw Choong ◽  
Kia Li Lau ◽  
...  

The paper evaluates the adsorptive potential of thiourea-modified poly(acrylonitrile-co-acrylic acid), (TA-poly(AN-co-AA)) for the uptake of cationic methylene blue (MB) from aquatic environments via a batch system. TA-poly(AN-co-AA) polymer was synthesized through redox polymerization and modified with thiourea (TA) where thioamide groups were introduced to the surface. Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), CHNS and Zetasizer were used to characterize the physico-chemical and morphological properties of prepared TA-poly(AN-co-AA). Afterwards, it was confirmed that incorporation of thioamide groups was successful. The adsorption kinetics and equilibrium adsorption data were best described, respectively, by a pseudo-second-order model and Freundlich model. Thermodynamic analysis showed the exothermic and spontaneous nature of MB uptake by TA-poly(AN-co-AA). The developed TA-poly(AN-co-AA) polymer demonstrated efficient separation of MB dye from the aqueous solution and maintained maximum adsorption capacity after five regeneration cycles. The findings of this study suggested that synthesized TA-poly(AN-co-AA) can be applied successfully to remove cationic dyes from aquatic environments.

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaodong Li

Using straw and urea as raw materials, biochar (BC) and g-C3N4 were prepared by oxygen-free pyrolysis at 300°C and 550°C. BC/g-C3N4 was prepared by loading different amounts of g-C3N4 onto the surface of biochar and characterized by SEM and FT-IR. The adsorption effect on methylene blue (MB) was investigated from the aspects of dosage and pH. The studies of adsorption equilibrium isotherms and the kinetic and the thermodynamic parameters on the BC/g-C3N4 adsorbents are discussed. The results showed that BC/g-C3N4 0.16 g/L with a doping ratio of 1 : 3 was added to the MB solution with an initial concentration of 50 mg/L and pH=11. The adsorption rate and adsorption amount were 96.72% and 302.25 mg/g, respectively. The adsorption process included surface adsorption and intraparticle diffusion, which conformed to the pseudo-second-order kinetic model and Langmuir-Freundlich model. Thermodynamic parameters (ΔG0<0, ΔH0>0, and ΔS0>0) showed that the adsorption reaction is spontaneous, which positively correlated with temperature.


Author(s):  
J. W. Soo ◽  
L. C. Abdullah ◽  
S. N. A. M. Jamil ◽  
A. A. Adeyi

Abstract In this paper, the adsorptive performance of synthesized thiourea (TU) modified poly(acrylonitrile-co-acrylic acid) (TU-P(AN-co-AA)) polymeric adsorbent capturing p-nitrophenol (PNP) from aqueous solution was investigated. The TU-P(AN-co-AA) was synthesized via the redox polymerization method with acrylonitrile (AN) and acrylic acid (AA) as monomers and modified chemically with thiourea (TU). Characterization analysis with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), CHNS, zeta potential measurement, Brunauer–Emmett–Teller (BET) surface analysis and thermal analyses were carried out to determine the morphology and physico-chemical properties of synthesized polymer. The characterization results had indicated successful surface modification of polymer with TU. The performance of TU-P(AN-co-AA) in removal of PNP were investigated under various experimental parameters (adsorbent dosage, initial adsorbate concentration, contact time and temperature). The results had demonstrated that the Freundlich isotherm model and pseudo-second-order kinetic model best described the equilibrium and kinetic data, respectively. Thermodynamic studies had showed that the uptake of PNP by TU-P(AN-co-AA) was spontaneous and exothermic in nature. The results from the regeneration studies suggested that the TU-P(AN-co-AA) polymer is a reusable adsorbent with great potential in removing PNP from wastewater.


NANO ◽  
2019 ◽  
Vol 14 (02) ◽  
pp. 1950019 ◽  
Author(s):  
Junjie Chen ◽  
Yonggan Ju ◽  
Hongling Chen

Fe3O4 nanoparticles coating with poly dimethyl diallyl ammonium chloride (Fe3O4/PDDA) as novel magnetic adsorbents were synthesized with chemical co-precipitation method to study the removal capacity of organic phosphonates from aqueous solution. The as-prepared magnetic absorbents were characterized for the morphology, material structure and surface properties by SEM, TEM, FT-IR, XRD, TGA and BET. HEDP was employed as a common organic phosphonate to investigate the adsorption performance. Substantial quaternary ammonium groups existing on the surface of Fe3O4/PDDA could enhance the absorption of HEDP with electrostatic attraction. In the optimum condition (4[Formula: see text]mg adsorbent dosage, 11.0 pH, 36[Formula: see text]mg/L HEDP solution and 120[Formula: see text]min adsorption time), the maximum adsorption capacity ([Formula: see text]) for HEDP could reach 254.86[Formula: see text]mg/g. The kinetic study revealed that the adsorption process followed the pseudo-second-order model. The adsorption isotherm fitted closely to the Freundlich model. The as-prepared magnetic adsorbents exhibited notable reusability in some cycles and were easily separated from the solution with the external magnetic field. These as-prepared Fe3O4/PDDA nanoparticles have the potential as an environmental-friendly adsorbent for organic phosphonates removal from waste-water.


2015 ◽  
Vol 14 (04) ◽  
pp. 1550009 ◽  
Author(s):  
N. M. Mubarak ◽  
Y. T. Fo ◽  
Hikmat Said Al-Salim ◽  
J. N. Sahu ◽  
E. C. Abdullah ◽  
...  

The study on the removal of methylene blue (MB) and orange-G dyes using magnetic biochar derived from the empty fruit bunch (EFB) was carried out. Process parameters such as pH, adsorbent dosage, agitation speed and contact time were optimized using Design-Expert Software v.6.0.8. The statistical analysis reveals that the optimum conditions for the maximum adsorption of MB are at pH 2 and pH 10, dosage 1.0 g, and agitation speed and contact time of 125 rpm and 120 min respectively. While for orange-G, at pH 2, dosage 1.0 g, and agitation speed and contact time of 125 rpm and 120 min respectively. The maximum adsorption capacity of 31.25 mg/g and 32.36 mg/g for MB and orange-G respectively. The adsorption kinetic for both dyes obeyed pseudo-second order.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohamed S. Yahia ◽  
Ahmed S. Elzaref ◽  
Magdy B. Awad ◽  
Ahmed M. Tony ◽  
Ahmed S. Elfeky

Abstract Commercial Granulated Active Carbon (GAC) has been modified using 10 Gy dose Gamma irradiation (GAC10 Gy) for increasing its ability of air purification. Both, the raw and treated samples were applied for removing Chlorpyrifos pesticide (CPF) from ambient midair. Physicochemical properties of the two materials were characterized by Fourier Transform Infrared (FT-IR) and Raman spectroscopy. The phase formation and microstructure were monitored using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), supported with Energy-Dispersive X-ray (EDX). The Surface area measurement was detected using BET particle size prosometry. Obtained outcomes showed that, the maximum adsorption capacity, given by Langmuir equations, was greatly increased from 172.712 to 272.480 mg/g for GAC and GAC10 Gy, respectively, with high selectivity. The overall removal efficiency of GAC10 Gy was notably comparable to that of the original GAC-sorbent. The present study indicated that, gamma irradiation could be a promising technique for treating GAC and turned it more active in eliminating the pesticides pollutants from surrounding air. The data of equilibrium has been analyzed by Langmuir and Freundlich models, that were considerably better suited for the investigated materials than other models. The process kinetics of CPF adsorbed onto both tested carbon versions were found to obey the pseudo first order at all concentrations with an exception at 70 mg/l using GAC, where, the spontaneous exothermic adsorption of Chlorpyrifos is a strong function for the pseudo-first order (PFO) and pseudo second order (PSO) kinetics.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Jhonatan R. Guarín ◽  
Juan Carlos Moreno-Pirajan ◽  
Liliana Giraldo

Currently, there is a great pollution of water by the dyes; due to this, several studies have been carried out to remove these compounds. However, the total elimination of these pollutants from the aquatic effluents has represented a great challenge for the scientific community, for which it is necessary to carry out investigations that allow the purification of water. In this work, we studied the bioadsorption of methylene blue on the surface of the biomass obtained from the algae D. antarctica. This material was characterized by SEM and FTIR. To the data obtained in the biosorption experiments, different models of biosorption and kinetics were applied, finding that the best fit to the obtained data is given by applying the pseudo-second-order models and the Toth model, respectively. It was also determined that the maximum adsorption capacity of MB on the surface of the biomass is 702.9 mg/g, which shows that this material has great properties as a bioadsorbent.


2021 ◽  
Vol 43 (4) ◽  
pp. 436-436
Author(s):  
Nida Shams Jalbani Nida Shams Jalbani ◽  
Amber R Solangi Amber R Solangi ◽  
Shahabuddin Memon Shahabuddin Memon ◽  
Ranjhan Junejo Ranjhan Junejo ◽  
Asif Ali Bhatti Asif Ali Bhatti

In current study, the diphenylaminomethylcalix[4]arene (3) was synthesized and immobilized onto silica surface to prepare a selective, regenerable and stable resin-4. The synthesized resin-4 has been characterized by FT-IR spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDX) and Brunauer-Emmett-Teller (BET) techniques. To check the adsorption capacity of resin-4, the batch and column adsorption methodology were applied and it has observed that the resin-4 was selectively removed Hg2+ ions under the optimized parameters. The maximum adsorption capacity was obtained at pH 9 using 25 mg/L of resin-4. Under the optimal conditions, different equilibrium, kinetic and thermodynamic models were applied to experimental data. The results show that adsorption mechanism is chemical in nature following Langmuir model with good correlation coefficient (R2=0.999) and having 712.098 (mmol/g) adsorption capacity. The energy of calculated from D-R model suggests the ion exchange nature of the adsorption phenomenon. Dynamic adsorption experiments were conducted using Thomas model. The maximum solid phase concentration (qo) was 7.5 and rate constant was found to be 0.176 with (R2=0.938) for Hg2+ ions. The kinetic study describes that the adsorption mechanism follows pseudo second order (R2=0.999). The thermodynamic parameters such as ∆H (0.032 KJ/mol) and ∆S (0.127 KJ/mol /K) and ∆G (-5.747,-6.306, -7.027 KJ/mol) shows that the adsorption of Hg2+ ion is endothermic and spontaneous. The reusability of resin-4 was also checked and it has observed that the after 15 cycle only 1.2 % adsorption reduces. Moreover, the resin-4 was applied on real wastewater samples obtained from local industrial zone of Karachi, Sindh-Pakistan.


Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 681 ◽  
Author(s):  
Fabian Arias Arias ◽  
Marco Guevara ◽  
Talia Tene ◽  
Paola Angamarca ◽  
Raul Molina ◽  
...  

Recently, green-prepared oxidized graphenes have attracted huge interest in water purification and wastewater treatment. Herein, reduced graphene oxide (rGO) was prepared by a scalable and eco-friendly method, and its potential use for the removal of methylene blue (MB) from water systems, was explored. The present work includes the green protocol to produce rGO and respective spectroscopical and morphological characterizations, as well as several kinetics, isotherms, and thermodynamic analyses to successfully demonstrate the adsorption of MB. The pseudo-second-order model was appropriated to describe the adsorption kinetics of MB onto rGO, suggesting an equilibrium time of 30 min. Otherwise, the Langmuir model was more suitable to describe the adsorption isotherms, indicating a maximum adsorption capacity of 121.95 mg g−1 at 298 K. In addition, kinetics and thermodynamic analyses demonstrated that the adsorption of MB onto rGO can be treated as a mixed physisorption–chemisorption process described by H-bonding, electrostatic, and π − π interactions. These results show the potential of green-prepared rGO to remove cationic dyes from wastewater systems.


Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1449 ◽  
Author(s):  
Xianchun Hu ◽  
Xianfeng Du

Microporous starch (MPS) granules were formed by the partial hydrolysis of starch using α–amylase and glucoamylase. Due to its biodegradability and safety, MPS was employed to adsorb tea polyphenols (TPS) based on their microporous characteristics. The influences of solution pH, time, initial concentration and temperature on the adsorptive capacity were investigated. The adsorption kinetics data conformed to the pseudo second–order kinetics model, and the equilibrium adsorption data were well described by the Langmuir isotherm model. According to the fitting of the adsorption isotherm formula, the maximum adsorption capacity of TPS onto MPS at pH 6.7 and T = 293 K was approximately 63.1 mg/g. The thermodynamic parameters suggested that the adsorption of TPS onto MPS was spontaneous and exothermic. Fourier transform infrared (FT–IR) analysis and the thermodynamics data were consistent with a physical adsorption mechanism. In addition, MPS-loaded TPS had better stability during long-term storage at ambient temperature.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Preeti S. Kulkarni ◽  
Varuna S. Watwe ◽  
Abubakar J. Hipparge ◽  
Sana I. Sayyad ◽  
Rutika A. Sonawane ◽  
...  

AbstractThe potential of uncharred biomaterial derived from dry leaves of Ficusbenjamina (Family: Moraceae,local name: Weeping Fig) plant to remove Cr(VI) from aqueous samples was investigated. In the present work, treatment of dilute acids was used for activating the adsorption centres on the biomass instead of cumbersome charring process. The plant material was characterized using FT-IR, FE-SEM and EDX. Various influencing factors such as pH of equilibrating solution, contact time, Cr (VI) concentrations, adsorbent dose and temperature were optimized to obtain maximum sorption efficacy. The interactions among the biomaterial and Cr (VI) in water were studied by fitting the sorption data in four different adsorption isotherms. The data fitting and experimental evidences indicated formation of monolayer of Cr(VI) over the biomass surface. The process followed pseudo-second order kinetics and was thermodynamically spontaneous under laboratory conditions and reached equilibrium in 24 hours. Maximum adsorption capacity of 56.82 mg/g was obtained at the pH 2 when the concentration before adsorption was 200 mg L−1 of Cr(VI) with 24 hours of equilibration time and 2.50 g L−1 of dose of biomaterial at room temperature. The sorption efficiency was found to be better than many charred bio-based materials.


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