Selective Adsorption and Separation of Organic Dyes by Poly(acrylic acid) Hydrogels Formed with Spherical Polymer Brushes and Chitosan

2018 ◽  
Vol 71 (11) ◽  
pp. 846 ◽  
Author(s):  
Rui Zhang ◽  
Hongwei Peng ◽  
Tianxu Zhou ◽  
Min Li ◽  
Xuhong Guo ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Polymer Brushes ◽  
Electrostatic Interactions ◽  
Separation Efficiency ◽  
Organic Dyes ◽  
Selective Adsorption ◽  
Cationic Dyes ◽  
Order Kinetic ◽  
Double Network ◽  
Poly Acrylic Acid

Direct discharge of industry organic dyes has caused serious environmental pollution. In this study, a series of double network poly(acrylic acid) (PAA) hydrogels were fabricated with spherical polymer brushes (SPBs) and chitosan (CS) as crosslinker. Neutral spherical polyelectrolyte brushes of polystyrene–poly-N-isopropylacrylamide (PNIPAM@PS) in which poly(N-isopropylacrylamide) (PNIPAM) arms were grafted on polystyrene (PS) nanospheres, were employed as macro-crosslinkers. The innumerable hydrogen bonds both between the highly entangled PAA chains and between PNIPAM and the PAA chains composed the first network of the hydrogels. The electrostatic interactions between CS and the PAA chains formed the second network of the hydrogels. These double network hydrogels, named PNIPAM@PS/CS/PAA, achieve good compressive performance and a low swell ratio because of their compact structure through plentiful hydrogen bonding and electrostatic interactions. The hydrogel could absorb cationic dyes from water with high separation efficiency and selectivity due to the electrostatic interaction between the carboxy groups and dye molecules. The adsorption process fitted a pseudo-second-order kinetic model and Langmuir isotherm model very well. Moreover, the hydrogel can separate cationic dyes from mixed dye solutions through electrostatic interactions. After being loaded with silver nanoparticles, the obtained silver@hydrogel exhibited a good capacity for the photocatalytic degradation towards different dyes. The hydrogels are promising for dye-containing wastewater treatment.

Adsorption of Dyes onto Sodium Alginate Graft Poly(Acrylic Acid-co-2-Acrylamide-2-Methyl Propane Sulfonic Acid)/ Kaolin Hydrogel Composite

2017 ◽  
Vol 25 (8) ◽  
pp. 627-634 ◽  
Author(s):  
Linhui Zhu ◽  
Chengdong Guan ◽  
Bin Zhou ◽  
Zhentao Zhang ◽  
Rui Yang ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Sodium Alginate ◽  
Xylenol Orange ◽  
Methyl Violet ◽  
Cationic Dyes ◽  
Anionic Dyes ◽  
Hydrogel Composite ◽  
Adsorption Capacities ◽  
Initial Ph ◽  
Poly Acrylic Acid

Adsorption of four dyes, namely methyl violet (MV), rhodamine 6G (R6G), acid chrome blue K (AK) and xylenol orange (XO) onto sodium alginate graft poly(acrylic acid-co-2-acrylamide-2-methyl-1-propanesulfonicacid)/kaolin (SA-g-P(AA-co-AMPS)/KL) hydrogel composite is studied. The factors influencing the adsorption capacities, including the initial concentrations of dye solutions, contact time, initial pH values and dosage of the adsorbent as well as ionic strength of the solution are discussed. It is more effective for the composite to adsorb cationic dyes such as MV and R6G rather than anionic dyes AK and XO. The maximum adsorption capacities of MV, R6G, AK and XO are 1361.1, 1627.8, 563.5 and 312.4 mg/g, respectively. The adsorption thermodynamics for the four dyes are in accordance with both the Freudlich and Redlich-Peterson equations. It is shown that adsorption of the cationic dyes R6G and MV is spontaneous, while that of anionic dyes AK and XO is not. The kinetics studies show that the adsorption of the four dyes fitted a pseudo-second-order equation.

Amino-Functionalized Multi-Walled Carbon Nanotubes as Novel Adsorbents for Selective Adsorption of Anionic Dyes in Aqueous Solution

NANO ◽  
2015 ◽  
Vol 10 (05) ◽  
pp. 1550065 ◽  
Author(s):  
Hui Huang ◽  
Jingang Yu ◽  
Wei Liu ◽  
Xinyu Jiang
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solution ◽  
Adsorption Kinetics ◽  
Organic Dyes ◽  
Selective Adsorption ◽  
Order Kinetic ◽  
Equilibrium Isotherms ◽  
Anionic Dyes ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

In this study, amino-functionalized multi-walled carbon nanotubes ( MWCNTs - NH 2) were successfully synthesized via an improved method and used for removal of organic dyes in aqueous solution. The synthesized MWCNTs - NH 2 were characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscope (SEM), etc. The adsorption capacity and selectivity of MWCNTs - NH 2 for organic dyes was evaluated using rhodamine B ( RhB ), malachite green (MG), methyl orange (MO) and congo red (CR) as models. The selective adsorption toward anionic dyes was found for the MWCNTs - NH 2, and MO was selected as a typical anionic dye to deeply investigate the adsorption kinetics, equilibrium isotherms and thermodynamic parameters of the adsorption process. The adsorption kinetics and equilibrium isotherms data fitted well with the pseudo-second-order kinetic equation and Langmuir isotherm model. The thermodynamics study revealed that the adsorption of MO onto MWCNTs - NH 2 was spontaneous, exothermic and physisorptive in nature. The results indicated that MWCNTs - NH 2 are promising nanomaterials for removal of anionic dyes from industrial wastewater.

A pH-sensitive, strong double-network hydrogel: Poly(ethylene glycol) methyl ether methacrylates-poly(acrylic acid)

2011 ◽  
Vol 50 (6) ◽  
pp. 423-430 ◽  
Author(s):  
Sina Naficy ◽  
Joselito M. Razal ◽  
Philip G. Whitten ◽  
Gordon G. Wallace ◽  
Geoffrey M. Spinks
Keyword(s):  
Acrylic Acid ◽  
Ethylene Glycol ◽  
Methyl Ether ◽  
Ph Sensitive ◽  
Poly Ethylene Glycol ◽  
Double Network ◽  
Poly Ethylene ◽  
Glycol Methyl Ether ◽  
Poly Acrylic Acid

scholarly journals Sustainable Development of Magnetic Chitosan Core–Shell Network for the Removal of Organic Dyes from Aqueous Solutions

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7701
Author(s):  
Karthik Rathinam ◽  
Xinwei Kou ◽  
Ralph Hobby ◽  
Stefan Panglisch
Keyword(s):  
Electrostatic Interactions ◽  
Dye Removal ◽  
Adsorption Process ◽  
Organic Dyes ◽  
Core Shell ◽  
Order Kinetic ◽  
Alizarin Red ◽  
Anthraquinone Dye ◽  
Magnetic Chitosan ◽  
Repulsive Forces

The wide use of alizarin red S (ARS), a typical anthraquinone dye, has led to its continued accumulation in the aquatic environment, which causes mutagenic and carcinogenic effects on organisms. Therefore, this study focused on the removal of ARS dye by adsorption onto a magnetic chitosan core–shell network (MCN). The successful synthesis of the MCN was confirmed by ATR-FTIR, SEM, and EDX analysis. The influence of several parameters on the removal of ARS dye by the MCN revealed that the adsorption process reached equilibrium after 60 min, pH played a major role, and electrostatic interactions dominated for the ARS dye removal under acidic conditions. The adsorption data were described well by the Langmuir isotherm and a pseudo-second order kinetic model. In addition to the preferable adsorption of hydrophobic dissolved organic matter (DOM) fractions onto the MCN, the electrostatic repulsive forces between the previously adsorbed DOM onto MCN and ARS dye resulted in lower ARS dye removal. Furthermore, the MCN could easily be regenerated and reused for up to at least five cycles with more than 70% of its original efficiency. Most importantly, the spent MCN was pyrolytically converted into N-doped magnetic carbon and used as an adsorbent for various dyes, thus establishing a waste-free adsorption process.

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