Kinetics and Thermodynamics Study of Thiosulfate Removal from Water by Calcined MgAl-CO3 Layered Double Hydroxides

2011 ◽  
Vol 396-398 ◽  
pp. 880-885
Author(s):  
Cui Yu Geng ◽  
Xiao Yu ◽  
Zheng Chang ◽  
Xiao Dong Lei ◽  
Xiao Ming Sun ◽  
...  
Keyword(s):  
Memory Effect ◽  
Layered Double Hydroxides ◽  
Reaction Rate ◽  
Langmuir Equation ◽  
Contaminated Water ◽  
Equilibrium Isotherm ◽  
Kinetics And Thermodynamics ◽  
Pseudo Second Order ◽  
Uptake Process ◽  
Double Hydroxides

Layered double hydroxides (LDHs) are potential scavengers for anionic contaminants due to their “memory effect”. Here we report the removal of thiosulfate anion from contaminated water by calcined MgAl–CO3 LDH (CLDH). The results indicate that CLDH exhibits a good performance in adsorption of thiosulfate.We studied the kinetics and thermodynamics of adsorption of thiosulfate from water. The equilibrium isotherm showed that the uptake of thiosulfate anion well agrees with the Langmuir equation, the positive value of △HӨ demonstrates the endothermic feature of the adsorption, the pseudo-second order kinetics model can be uItalic textsed to describe the uptake process and the value of Ea was calculated to be 75.898 kJ/mol. Our results suggest that the process of thiosulfate uptaking was controlled by the reaction rate of thiosulfate with the CLDH rather than diffusion.

scholarly journals A Comparative Study on The Adsorption Behavior of Congo Red on to ZnAl and ZnCr Layered Double Hydroxides

2020 ◽  
Vol 9 (2) ◽  
pp. 108-116
Author(s):  
Tarmizi Taher ◽  
◽  
Nyanyu Ummu Hani ◽  
Neza Rahayu Palapa ◽  
Risfidian Mohadi ◽  
...  
Keyword(s):  
Experimental Data ◽  
Surface Area ◽  
Adsorption Kinetics ◽  
Layered Double Hydroxides ◽  
Congo Red ◽  
Adsorption Process ◽  
Bet Surface Area ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Double Hydroxides

In this work, two synthetic layered double hydroxides (LDH) consists of Zn2+ as M2+ cation with different M3+ cation, i.e., Al3+ and Cr3+ were used as an adsorbent for Congo Red removal aqueous solution. Both Zn-Al and Zn-Cr LDH were characterized by X-ray diffraction, FT-IR, and BET surface area analyzer. The effect of contact time, initial dye concentration, and temperature were evaluated in a batch technique in order to investigate the characteristic of Congo Red adsorption onto both adsorbents. The experimental data were assessed according to the parameter of adsorption kinetics, isotherm, and thermodynamics. The results of LDH characterization showed that Zn-Al LDH has a higher interlayer distance than Zn-Cr LDH, although Zn-Cr LDH has a higher surface area. The FT-IR analysis indicated the interlayer space of both Zn-Cr and Zn-Al LDH was dominated by CO32- as the interlayer anion species. The adsorption kinetics study of Congo Red on both LDH revealed that the adsorption process followed the pseudo-second-order model. For the adsorption isotherm, the experimental data fit well with the Freundlich model rather than the Langmuir model. The thermodynamic study indicated that the adsorption process that occurred on both adsorbents was spontaneous with exothermic nature.

scholarly journals Luminescent Layered Double Hydroxides Intercalated with an Anionic Photosensitizer via the Memory Effect

Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 153 ◽  
Author(s):  
Alexandre Teixeira ◽  
Alysson Morais ◽  
Ivan Silva ◽  
Eric Breynaert ◽  
Danilo Mustafa
Keyword(s):  
Aqueous Solution ◽  
Memory Effect ◽  
Layered Double Hydroxides ◽  
Efficient Energy Transfer ◽  
Efficient Energy ◽  
Calcination Temperatures ◽  
Anionic Species ◽  
Benzenetricarboxylic Acid ◽  
Double Hydroxides ◽  
Rehydration Process

Layered double hydroxides (LDHs) containing Eu3+ activators were synthesized by coprecipitation of Zn2+, Al3+, and Eu3+ in alkaline NO3−-rich aqueous solution. Upon calcination, these materials transform into a crystalline ZnO solid solution containing Al and Eu. For suitably low calcination temperatures, this phase can be restored to LDH by rehydration in water, a feature known as the memory effect. During rehydration of an LDH, new anionic species can be intercalated and functionalized, obtaining desired physicochemical properties. This work explores the memory effect as a route to produce luminescent LDHs intercalated with 1,3,5-benzenetricarboxylic acid (BTC), a known anionic photosensitizer for Eu3+. Time-dependent hydration of calcined LDHs in a BTC-rich aqueous solution resulted in the recovery of the lamellar phase and in the intercalation with BTC. The interaction of this photosensitizer with Eu3+ in the recovered hydroxide layers gave rise to efficient energy transfer from the BTC antennae to the Eu3+ ions, providing a useful tool to monitor the rehydration process of the calcined LDHs.

scholarly journals Kinetic Adsorption of Direct Yellow Onto Zn/Al and Zn/Fe Layered Double Hydroxides

2019 ◽  
Vol 4 (4) ◽  
pp. 101
Author(s):  
Neza Rahayu Palapa ◽  
Bakri Rio Rahayu ◽  
Tarmizi Taher ◽  
Aldes Lesbani ◽  
Risfidian Mohadi
Keyword(s):  
Layered Double Hydroxides ◽  
Kinetic Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Order ◽  
Bet Method ◽  
Pseudo Second Order ◽  
Time Variations ◽  
Co Precipitation ◽  
Double Hydroxides

Zn/Al and Zn/Fe layered double hydroxides has successfully synthesized by co-precipitation methods with molar ration 3:1. The samples were characterized using X-Ray Diffraction, Fourier Transform Infrared Spectroscopy and Surface Area using BET method. In this study, Zn/Al and Zn/Fe layered double hydroxides were used to remove direct yellow dye in aqueous solution. The experiments were carried out time variations with the aim of observing the kinetic studies. The results showed that the adsorption of direct yellow onto Zn/Al and Zn/Fe layered double hydroxides based on co-efficient correlation kinetic models more fit using pseudo-second-order than pseudo-first-order.

Sign in / Sign up

Export Citation Format

Share Document