Novel Superadsorbent Highly Porous Hydrogel Based on Arabic Gum and Acrylamide Grafts for Fast and Efficient Methylene Blue Removal (original) (raw)
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Batch adsorption experiments were carried out for the removal of methylene blue (MB) cationic dye from aqueous solution using organic/inorganic hydrogel nanocomposite of titania incorporated sodium alginate crosslinked polyacrylic acid (SA-cl-poly(AA)-TiO 2). The hydrogel was prepared by graft copoly-merization of acrylic acid (AA) onto sodium alginate (SA) biopolymer in the presence of a crosslinking agent, a free radical initiator and TiO 2 nanoparticles. The hydrogel exhibited a high swelling capacity of 412.98 g/g. The factors influencing adsorption capacity of the absorbents such as pH of the dye solutions, initial concentration of the dye, amount of absorbents, and temperature were investigated and used to propose a possible mechanism of adsorption. The adsorption process concurs with a pseudo-second-order kinetics and with Langmuir isotherm equation. A very high adsorption capacity (Q max = 2257.36 (mg/g)) and a correlation coefficient of 0.998 calculated from isotherm equations show the high efficiency of the absorbent and thus expected to be a good candidate as an absorbent for water treatment.
Journal of Colloid and Interface Science, 2006
The removal of methylene blue (MB) in water with the superabsorbent hydrogel (SH) formed by modified gum arabic, polyacrylate, and polyacrylamide was investigated. The SH exhibited excellent performance in MB absorption. The maximum absorption capacity was 48 mg of the dye per g of SH, representing 98% of the MB removed. Experimental parameters were used as follows: pH 8, hydrogel mass 50 mg, and initial concentration of MB 50 mg L−1. In a procedure with an individual solution of orange II, an opposite effect related to the MB was observed: the hydrogel only absorbed water, resulting in an orange II-richer solution. The orange II concentration in solution increased about 50 times (relative to the initial concentration). In another experiment using an aqueous mixture of orange II and MB, the SH absorbed the MB exclusively. Compared to the MB, the orange II is separated from water by SH selectivity-absorption through an inverse process. This effect was attributed to the formation of a ionic complex between the imine groups of MB and the ionized carboxylic groups of SH.The hydrogel has an excellent performance of methylene blue absorption (ca. 98%). This effect has assigned to the formation of an ionic complex between the imines groups of methylene blue and the ionized carboxylic groups of hydrogel.
Iranian Journal of Environmental Health Science & Engineering, 2010
Dye removal from wastewater has received considerable attention with several classes of dye being investigated. Methylene blue has wide applications and can cause some harmful effects in humans. The use of clean technology of low-priced and biodegradable absorbents could be a good tool to minimize the environmental impact caused by dye manufacturing and textile effluents.The present study deals with the preparation of a novel sIPN (semi interpenetrating) hydrogel composed of copolymer of acrylamide and acrylicacid with poly vinyl alcohol as linear polymer there in. The adsorption abilities of hydrogels with different molar ratios for removal of methylene blue from aqueous solutions were investigated. A weighed quantity of dry hybrid hydrogel was immersed in 50 ppm MB solution and kept at 37 o C. The amount of MB adsorbed was measured spectrophotometrically (λ= 661.6 nm) in periodically taken solution samples. The maximum dye adsorption concentration for hydrogel composites was 95% a...
Macromol
Removal of dyes through adsorption from wastewater has gained substantial interest in recent years, especially in development of hydrogel based adsorbents, owing to their easy use and economical nature. The aim of the present study was to design a super-adsorbent hydrogel based on sodium styrenesulfonate (NaSS) monomer for removal of dyes like methylene blue (MB). NaSS displays both an aromatic ring and strongly ionic group in its monomer structure that can enhance adsorption capacity. Poly(sodium styrenesulfonate-co-dimethylacrylamide) hydrogels were prepared by solution free radical polymerization using gelatin methacryloyl (GelMA) as crosslinker, creating a highly porous, three-dimensionally crosslinked polymer network contributing to higher swelling ratios of up to 27,500%. These super-adsorbent hydrogels exhibited high adsorption capacity of 1270 mg/g for MB adsorption with above 98% removal efficiency. This is the first report for such a high adsorption capacity for dye absorb...
2021
The performance of poly(methacrylic acid-co-acrylamide/nanoclay composite (poly(MAA-co-AAm)/NCC) hydrogel to adsorb methylene blue (MB) dye from aqueous solutions was investigated and the adsorption efficiency was improved by incorporating Cloisite 30B nanoclays in the adsorbent structure. The hydrogels were analyzed using FTIR, XRD, TGA, and SEM analysis. The effect of adsorbent dose, temperature, initial dye concentration, contact time, and pH on the efficiency of the adsorption process was investigated. Adsorption efficiencies of 98.57 and 97.65% were obtained for poly(MAA-co-AAm)/NCC and poly(MAA-co-AAm) hydrogels, respectively. Kinetic study revealed that the adsorption process followed pseudo-first-order kinetic model and α-parameter values of 6.558 and 1.113 mg/g.min were obtained for poly(MAA-co-AAm)/NCC and poly(MAA-co-AAm) hydrogels, respectively indicating a higher ability of nanocomposite hydrogel in adsorbing MB-dye. In addition, the results of the intra-particle diffus...
Hybrid hydrogel networks synthesized by the simple free radical polymerization of acrylamide, acrylamidoglycolic acid and cloisite sodium clay. To synthesize these hybrid hydrogels N,N'methylenebisacrylamide used as a cross linker and ammonium peroxydisulphate used as an initiator. The structural characterization of this poly(acrylamide-co-acrylamidoglycolic acid/cloisite hybrid hydrogels (PAAGC), were done using Fourier transform infrared spectroscopy. The resulting hybrid networks was used as an adsorbent for studying the effectiveness in the removal of methylene blue (MB), which is having a wide range of use in different fields such as biology and chemistry. The effects of contact time, initial sorbate concentration, pH, and dose of adsorbent were studied to optimize the adsorption capacity. The batch sorption technique employed, revealed a maximum adsorption. Adsorption isotherms and Kinetic models were fitted to know the adsorption mechanism. This Hybrid hydrogels exhibited excellent performance in MB adsorption. The investigations demonstrated that the PAAGC can be based as an efficient adsorbent for the removal of MB from aqueous solution.
Journal of colloid and interface science, 2018
In this work, xanthan gum-cl-poly acrylic acid (XG-cl-pAA) hydrogel and xanthan gum-cl-poly acrylic acid/oxidized MWCNTs (XG-cl-pAA/o-MWCNTs) hydrogel nanocomposite was successfully surface modify by microwave assisted copolymerization, in which N, N'-methylenebisacrylamide (MBA) was used as a cross-linking agent. A copolymerization of acrylic acid (AA) onto xanthan gum (XG) initiated by microwave radiation method. Different weight percentages of oxidized MWCNTs were incorporated into the hydrogel matrix during the grafting reaction. An optimum hydrogel based on maximum swelling capacity further incorporated with oxidized MWCNTs to form XG-cl-pAA/o-MWCNTs. The structure, thermal stability, wettability and morphology of XG-cl-PAA and XG-cl-PAA/o-MWCNTs were characterized by fourier transform infrared (FTIR), Raman, X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Contact angle, and scanning electron microscope (SEM). The effects of pH, contact time and equilibrium conce...
Polymer Bulletin, 2011
The present study examined the use of ghassoul, natural clay available in large quantities under the Atlas Mountains in Morocco, for the removal of the basic dye, methylene blue, from aqueous solutions. The effect of initial dye concentrations, agitation time, pH and temperature on adsorption capacities of methylene blue was investigated. The initial pH of the aqueous solution and the change of temperature (25-55 °C) were found to have little effect on the adsorption process. The adsorption was a rapid with 90-99% of the dye removed within the first 10-20 min. The adsorption kinetics are described successfully using a pseudo-second order rate equation and the rate constant decreases with increasing the initial concentration of MB. Experimental and calculated kinetic data for equilibrium are well expressed by Langmuir isotherm. The equilibrium adsorption capacity of ghassoul was determined with the Langmuir equation as well as the pseudo-second-order rate equation and found to be >290 mg dye per gram of the adsorbent. The results indicate that ghassoul could be employed as a low cost alternative to commercial activated carbon in wastewater treatment for the removal of colour and dyes.
International Journal of Biological Macromolecules, 2021
Synthetic hydrogel has been widely used in several applications, but poor mechanical stability and biodegradability limit their applications and raise environmental concerns. Here, a biodegradable hydrogel was developed via simple free-radical polymerization of poly(acrylic acid) (PAA) in the presence of cassava starch (CS) and poly (vinyl alcohol). The hydrogel showed exceptional mechanical and physical properties. The structural morphology changed at higher CS content from a dense fiber-like porous network to larger pores with thicker cell walls. Due to the formation of a double network structure via physical entanglement, the compressive modulus significantly increased from 27 kPa (CS 0 wt%) to 127 kPa (CS 50 wt%). Reducing synthetic content (PAA) to 25 wt % and increasing CS content to 50 wt% did not reduce the removal efficiency of the hydrogel toward methylene blue (MB). The maximum adsorption capacity of the CS50 hydrogel was 417.0 mg/g. Data fitting to theoretical models indicated monolayer adsorption of MB on a homogeneous surface via chemisorption. Removal efficiency was higher than 70% at the 5 th cycle of adsorption-desorption. The biodegradability and photodegradability of the hydrogel were improved by grafting with CS. The developed hydrogel represents an alternative biodegradable adsorbent for a sustainable system of wastewater treatment.
Polymers
The use of some hydrogels as adsorbents for pollutants removal from wastewater is limited due to their high swelling properties and the difficulty in recovering them after the adsorption process. To overcome these problems, a new hydrogel nanocomposite based on chitosan-grafted-polyacrylic acid/oxidized electrospun carbon nanofibers (CT-g-PAA/O-ECNFs) was prepared by an in situ grafting polymerization process. The prepared hydrogel nanocomposite was used as a novel effective and highly reusable adsorbent for the removal of methylene blue (MB) from polluted water with low cost. The morphology and the structure of CT-g-PAA/O-ECNFs were investigated by numerous techniques. The effect of incorporating O-ECNFs on the swelling capability of the prepared hydrogel was explored in distillated water and MB solution at normal pH. The effect of parameters including ratio of O-ECNFs, contact time, pH, initial concentration, and temperature on adsorption process were explored. The adsorption isot...