Simultaneous Removal of Cationic and Anionic Dyes from Environmental Water Using Montmorillonite-Pillared Graphene Oxide

Abstract

We investigate the removal of methyl orange (MO) and methylene blue (MB) from aqueous solution by montmorillonite-pillared graphene oxide (MGO). Experimental conditions were used that evaluate the potential of MGO in removing anionic and cationic dyes in single and binary systems, and we investigated the uptake capacity of MGO toward organic dye as a function of different pH, adsorbent dosage, temperature, and adsorption time. In the single system, the Langmuir and Freundlich adsorption models were used to describe the equilibrium isotherm and calculate the isotherm constants. Moreover, the pseudo-first-order and pseudo-second-order kinetic models were applied to study the mechanism of MGO adsorbing dyes. Thermodynamic studies demonstrated that the adsorption of MO and MB onto MGO was feasible and spontaneous. In the binary system, the adsorption capacities of MO and MB by MGO were dramatically higher than those in a single system. Therefore, through the recorded adsorption results under different conditions, we could illustrate that the MGO was absolutely used as an adsorbent to be capable of simultaneous removals of MO and MB.

Synthesis of CoZnAl‐layered double hydroxide/graphene oxide nanocomposite for the removal of methylene blue: Kinetic, thermodynamic, and isotherm studies

“…Figure a shows that the rise of pH is generally in favor of the adsorption process; however, its effect in the range of 5.5–8.5 is not significant. Similar results have been reported for the effect of pH on MB adsorption using montmorillonite‐pillared GO by Liu et al For further study, the graph of the zero point charge of CoZnAl‐LDH/GO was plotted. As shown in Figure b, pH zpc was obtained to be 6.4.…”

“…Of course, the electrostatic attraction force between MB and CoZnAl‐LDH/GO partially explains the adsorption mechanism. MB (a cationic dye) would be likely adsorb on CoZnAl‐LDH/GO through π—π bond interactions between the adsorbent and the aromatic ring of the dye . In pH values above pH zpc , the synergy effect of the electrostatic and π—π interactions provide more favorable conditions for the removal of MB.…”

Preparation of aerochitin‐TiO2 composite for efficient photocatalytic degradation of methylene blue

“…These organic pollutants contribute directly to water pollution and one of the major problems concerning organic pollutants is colored dyestuffs. These colored dyestuffs may be carcinogenic and mutagenic to humans and aquatic organisms . The wastewater treatment methods applied for the industrial effluents include coagulation flocculation, electro chemical oxidation, biodegradation, ion exchange, ozonation, and adsorption by activated carbon .…”

Recent Advances in Graphene Based TiO2 Nanocomposites (GTiO2Ns) for Photocatalytic Degradation of Synthetic Dyes

“…The chromophore is a covalently unsaturated group, which is responsible for the color production for the absorption in the UV or visible region; the auxochrome is supplementary to the chromophore, and influences the solubility in water and the affinity towards a particular support [195]. Concerning their uses, dyes can be anionic, cationic, and non-ionic; anionic dyes are divided into direct, acid, and reactive dyes, while cationic dyes are basic [196]. Water treatments by using GTiO 2 Ns in the photocatalytic degradations of dyes became very important due to the danger of dyes as environmental pollutants [142].…”