Calcined graphene/MgAl-layered double hydroxides for enhanced Cr(VI) removal

Pseudo-Janus Zn/Al-based nanocomposites for Cr(VI) sorption/remediation and evolved photocatalytic functionality

“…The peak of (0 0 3) centered at 2h = 11.5°suggests the intercalation of CO 2À 3 anions and water molecules into the interlayer galleries [6]. Elemental analysis of the Zn/Al-LDH by ICP OES after it is dissolved in dilute acid confirms that the Zn to Al molar ratio is 3.91:1, close to the Zn to Al feeding molar ratio of 4:1.…”

“…A great number of adsorbents, such as activated carbon, synthetic functional polymers, chemically modified polysaccharides, mesoporous aluminosilicate, heterostructured metal oxides, and biomass waste have been used for extricating Cr(VI) from aqueous solutions [3][4][5]. However, a class of compounds known as layered double hydroxides (LDH) or hydrotalcite-like compounds (HTlc) are undoubtedly one of the most promising adsorbents because of their good stability, large surface area, and high anion exchange capacity [1][2][3][4]6]. x is defined as the M 3+ /(M 2+ +M 3+ ) ratio that presents the layer charge density of LDH, whereas A nÀ is the interlayer anion of valence n (CO 2À 3 ; NO À 3 , Cl À etc.).…”

Magnetic calcinated cobalt ferrite/magnesium aluminum hydrotalcite composite for enhanced adsorption of methyl orange

“…Solution pH plays an important role in adsorption process due to its influences on the surface charge of the adsorbent and the extent of ionization or speciation of the adsorbate [39]. To determine and interpret the mechanisms of MO ions adsorption process over CoFe 2 O 4 /MgAl-LDO governing adsorption kinetics, the experimental data obtained were fitted to pseudo-first-order and pseudo-second-order kinetic models [12,34], with the respective equations defined as follows: where q e (mg/g) and q t (mg/g) are the amount of MO adsorbed on the adsorbent at equilibrium and at time t (min), respectively, t is the contact time, k 1 (min -1 ) and k 2 (g mg -1 min -1 ) are the rate constant of pseudo-first-order and pseudo-second-order model, respectively.…”

“…Adsorption data aforementioned were used for the evaluation of Gibbs free energy change ( G ∆ ), enthalpy change ( H ∆ ), and entropy change ( S ∆ ) using the following equations [37,39]: (12) where K d is the equilibrium constant that can be obtained from Langmiur isotherms at different temperatures, R (8.314J/mol k) is the universal gas constant, H ∆ and S ∆ can be calculated from the slope and intercept of van't Hoff plots of ln K d versus 1/T (shown in Fig. 7).…”

Functionalization of Graphene Oxide with 9-aminoanthracene for the Adsorptive Removal of Persistent Aromatic Pollutants from Aqueous Solution

“…21,22 In addition, the interaction between GO and pollutants is closely related to its surface structure which is tunable and flexible. 23,24 The surface of GO usually consists of two parts: unoxidized and oxidized zones. The unoxidized zone is referring to the lowly oxidized GOs while oxidized zones consist of both sp 3 zones and sp 2 clusters.…”