Enhanced Removal of Methylene Blue and Methyl Violet Dyes from Aqueous Solution Using a Nanocomposite of Hydrolyzed Polyacrylamide Grafted Xanthan Gum and Incorporated Nanosilica

Abstract

The synthesis and characterization of a novel nanocomposite is reported that was developed as an efficient adsorbent for the removal of toxic methylene blue (MB) and methyl violet (MV) from aqueous solution. The nanocomposite comprises hydrolyzed polyacrylamide grafted onto xanthan gum as well as incorporated nanosilica. The synthesis exploits the saponification of the grafted polyacrylamide and the in situ formation of nanoscale SiO2 by a sol-gel reaction, in which the biopolymer matrix promotes the silica polymerization and therefore acts as a novel template for nanosilica formation. The detailed investigation of the kinetics and the adsorption isotherms of MB and MV from aqueous solution showed that the dyes adsorb rapidly, in accordance with a pseudo-second-order kinetics and a Langmuir adsorption isotherm. The entropy driven process was furthermore found to strongly depend on the point of zero charge (pzc) of the adsorbent. The remarkably high adsorption capacity of dyes on the nanocomposites (efficiency of MB removal, 99.4%; maximum specific removal Qmax, 497.5 mg g(-1); and efficiency of MV removal, 99.1%; Qmax, 378.8 mg g(-1)) is rationalized on the basis of H-bonding interactions as well as dipole-dipole and electrostatic interactions between anionic adsorbent and cationic dye molecules. Because of the excellent regeneration capacity the nanocomposites are considered interesting materials for the uptake of, for instance, toxic dyes from wastewater.

Efficient Removal of Cationic and Anionic Dyes from Aqueous Solution Using Cellulose-g-p(AA-co-AM) Bio-Adsorbent

“…At lower pH values, most of the -COO -and -NH2 groups were protonated into −COOH and −NH3 + groups, and the abundant presence of H + ions on the surface of the adsorbent compete with the MB cationic dye molecules, resulting in low dye adsorption. In the alkaline solution, the CP bio-adsorbent was deprotonated, and the adsorption was increased due to the electrostatic interaction between the bio-adsorbent and MB dye molecules (Ghorai et al 2014). The adsorption of AR1 on the CP bio-adsorbent was higher at low pH, and it decreased with increasing pH value.…”

Synthesis of Nanosilica From Rice Husk and Optimization of the Removal of Crystal Violet Dye From Aqueous Solution

“…The XRD result (Fig. 2b) shows that there is a broad peak at 2θ = 22 o associated with amorphous silica and the size of the particles was estimated by half width of peak (β) using Scherer's formula: (3) where, K = 0.9 nm is a constant, λ= 1.542 Å is the wavelength of Cu-K α and β is the full width at half the maximum in radians of the X-ray diffraction peak. Using the above formula (Eq.…”

“…The adsorption process can be explained on the higher surface area as well as increased availability of the silanol sites on the surface. On the other hand, with higher adsorbent dosage, lower rate of adsorption has been presented due to the aggregation of adsorption and enhanced diffusion path length, which reduces the adsorption of dye molecules [3].…”

“…Water pollution in various industries such as printing, food, rubber, leather, plastic and cosmetic releases more than 100 tons dyes per year into the environment, so that such toxic cationic dyes cause the known harmful effects to humans and animals via the skin, eyes and respiratory tract [1][2][3][4]. Due to the dyes having complex aromatic structures and a matter of great concern, they are usually biologically non-degradable and present high stability and toxicity and it is therefore necessary to treat effluents containing these and related dyes [5][6].…”

Preparation and characterization of gum karaya hydrogel nanocomposite flocculant for metal ions removal from mine effluents

“…Different polysaccharides like pullulan-, dextran-, gum ghatti-, gum karaya-and gum xanthan-based polymeric materials and different nanomaterials have shown excellent potential as coagulants for the removal of different suspended particles from polluted waters. Furthermore, they have been also used as adsorbents for the removal of different metal ions and dyes from the aqueous solutions Gupta et al 2011;Mittal et al 2013a, b;Ghorai et al 2014;Saravanan et al 2013Saravanan et al , 2014Saravanan et al , 2015. Nanomaterials have also shown their potential as photo-catalysts Gupta 2011, 2012;Gupta et al 2012;Saleh 2015).…”