Layered double hydroxide (LDH)-coated attapulgite for phosphate removal from aqueous solution

2011 ◽  
Vol 64 (11) ◽  
pp. 2192-2198 ◽  
Author(s):  
Gan Fang-qun ◽  
Zhou Jian-min ◽  
Wang Huo-yan ◽  
Zhao Hong-ting

In this study, a composite adsorbent, layered double hydroxide (LDH)-coated attapulgite (LDH-AP), was synthesized and characterized. Its potential application for LDH stabilizer and phosphate (P) removal from aqueous solution was evaluated using the batch mode and continuous mode in a packed bed column. The batch experiments revealed that the data of P adsorption onto LDH-AP could be well described by the Freundlich equation, and the maximum adsorption capacity was estimated to be 6.9 mg/g. The column experiments were conducted in the tap water and the results indicated that the competing anions could slightly decrease phosphate removal. The saturated column was regenerated by 0.2 mol/L of NaOH and the regenerated column was examined for its reuse in phosphate removal. The results of this study suggested that attapulgite could be used as an applicable stabilizer of LDH and LDH-AP could be potentially used as a promising filtration medium for phosphate removal.

Author(s):  
Zaini Hamzah ◽  
Mohd Najif Ab Rahman ◽  
Yamin Yasin ◽  
Siti Mariam Sumari ◽  
Ahmad Saat

Layered double hydroxide with molar ratio of 4 (MAN 4) was synthesized by co-precipitation and followed by hydrothermal method. The compound was then later going through ion exchange with K2HPO4 for 48 hours to produce MgAlHPO4 (MAHP 4). The solid produced were characterized using X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR). Adsorption of lead solution by MAHP 4 was carried out using batch experiment by mixing the lead solution and the solid of layered double hydroxide. The effects of various parameters such as contact time, pH, adsorbent dosage and initial concentration were investigated. The optimum pH for lead removal was found to be at pH of 5 and the optimum time of lead removal was found at 2 hours. The isotherm data was analysed using Langmuir and the correlation coefficient of 0.998 was obtained. The maximum adsorption capacity, Qo (mg/g) of 500 mg/g was also recorded from the Langmuir isotherm. The remaining lead solution was determined by using EDXRF (Energy Dispersive X-Ray Fluorescence spectrometry) model MiniPal 4 (PAN analytical). The results in this study indicate that MAHP 4 was an interesting adsorbent for removing lead from aqueous solution.


2020 ◽  
Vol 10 (1) ◽  
pp. 33-45 ◽  
Author(s):  
Neza Rahayu Palapa ◽  
Risfidian Mohadi ◽  
Addy Rachmat ◽  
Aldes Lesbani

Layered double hydroxide (LDH) Cu/Al and Cu/Cr had been used as adsorbent of malachite green (MG) in aqueous solution. The properties of Cu/Al and Cu/Cr LDHs were analyzed by X-ray diffraction, surface area analysis (BET) and FTIR spectroscopy. Adsorption study of MG was achieved at pH 9. Adsorption of MG follows the pseudo-second-order kinetic model. Langmuir isotherm was suitable for adsorption of MG on both LDH with a maximum adsorption capacity of 59.52 mg/g. The thermodynamic study indicated that the adsorption process is physisorption, spontaneous, and endothermic process.  Adsorption of MG onto LDHs involve the acid-base interaction between adsorbent and adsorbate.


2011 ◽  
Vol 148-149 ◽  
pp. 1276-1279 ◽  
Author(s):  
Li Fang Zhang

In this study, the adsorption of C. I. Reactive Red 2 from aqueous solution on Ni-Al layered double hydroxide (LDH) was investigated in a batch system. The effect of Ni-Al molar ratio, pH, temperature and initial dye concentration on adsorption of the dye was carried out. The results showed that Ni-Al layered double hydroxide had higher capacity of removal of the dye. Ni-Al LDH with Ni-Al molar ratio of 3 exhibited the maximum dye removal at pH 4.0. Adsorption capacity of dye increased with increasing temperature or initial dye concentration. It was found that the adsorption equilibrium data followed the Langmuir adsorption model. The maximum adsorption capacity obtained from the Langmuir equation at temperature of 30°C was 333.3mg/g (R2=0.991) for the dye.


2016 ◽  
Vol 7 (2) ◽  
pp. 152-161 ◽  
Author(s):  
Hassiba Bessaha ◽  
Mohamed Bouraada ◽  
Louis Charles Deménorval

Layered double hydroxide Zn/(Al + Fe) with a molar ratio of 3:(0.85 + 0.15), designated as ZAF-HT, was synthetized by co-precipitation. Its calcined product CZAF was obtained by heat treatment of ZAF-HT at 500°C. The calcined and uncalcined materials were used to remove the acid dyes indigo carmine (IC) and green bezanyl-F2B (F2B) from water in batch mode. The synthetized materials were characterized by X-ray diffraction, scanning electron microscopy, Brunauer–Emmett–Teller analysis, Fourier transform infra-red spectroscopy and thermogravimetric/differential thermal analysis. The sorption kinetic data fitted a pseudo-second-order model. The adsorbed amounts of the calcined material were much larger than ZAF-HT. The maximum adsorption capacity of CZAF was found to be 617.3 mg g−1 for IC and 1,501.4 mg g−1 for F2B. The isotherms showed that the removal of IC and F2B by ZAF-HT and CZAF could be described by a Langmuir model. The thermodynamic parameters were also calculated. The negative values of standard free energy ΔG° indicate the spontaneity of sorption process. The reuse of CZAF was studied for both dyes and the calcined material showed a good stability for four thermal cycles.


2011 ◽  
Vol 36 (1-3) ◽  
pp. 178-186 ◽  
Author(s):  
Yong-Un Han ◽  
Won-Suk Lee ◽  
Chang-Gu Lee ◽  
Seong-Jik Park ◽  
Ki-Woo Kim ◽  
...  

2011 ◽  
Vol 287-290 ◽  
pp. 390-393
Author(s):  
Li Fang Zhang ◽  
Ying Ying Chen

The adsorption of C. I. Reactive Red 2 from aqueous solution on Zn-Al calcined layered double hydroxide (CLDH) was investigated. Experiments were carried out as a function of Zn-Al molar ratio, contact time, pH, temperature and initial dye concentration. The results showed that Zn-Al calcined layered double hydroxide had higher capacity of removal of the dye. Zn-Al CLDH with Zn-Al molar ratio of 3 and with pH range of 4.0-8.0 was found to be optimal for dye removal. Adsorption capacity of dye decreased with increasing temperature and increased with increasing initial dye concentration. It was found that the adsorption equilibrium data followed the Langmuir adsorption model. The maximum adsorption capacity obtained from the Langmuir equation at temperature of 30°C was 116.28mg/g (R2=0.9992) for the dye.


2020 ◽  
Vol 10 (3) ◽  
pp. 220-232
Author(s):  
Nurlisa Hidayati ◽  
Neza Rahayu Palapa ◽  
Bakri Rio Rahayu ◽  
Risfidian Mohadi ◽  
Elfita Elfita ◽  
...  

Layered double hydroxide (LDH) of Zn/Al and citrate-Zn/Al was prepared and used as an adsorbent of Congo red from aqueous solution. LDH was characterized by X-ray, FTIR, and BET analysis. Adsorption of Congo red was studied through kinetic, isotherm, and thermodynamic analyses. Zn/Al LDH has diffraction at 10.29o (003) with interlayer distance 8.59 Å and citrate-Zn/Al LDHs have anomalous diffraction at 7.57o (003) with interlayer distance 11.68 Å. The surface area of citrate-Zn/Al (40.50 m2 g-1) has higher than pristine LDH (1.97 m2 g-1). Adsorption of Congo red was conducted at pH 6 for Zn/Al LDH and at pH 8 for citrate-Zn/Al LDH. Adsorption of Congo red on both LDHs follows the pseudo-second-order kinetic model. The isotherm parameter follows the Freundlich isotherm model with maximum adsorption capacity 166.67 mg g-1 for Zn/Al and 249.99 mg g-1 for citrate-Zn/Al LDH. Adsorption of Congo red on both LDHs was classified as physical adsorption with energy 4.085-4.148 kJ mol-1. 


2021 ◽  
pp. 116774
Author(s):  
Fataneh Vasheghani Farahani ◽  
Mohammad Hassan Amini ◽  
Seyed Hamid Ahmadi ◽  
Seyed Amirabbas Zakaria

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