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

Abstract

The objective of this study was the synthesis of a novel nanocomposite (CoZnAl‐layered double hydroxide [LDH]/graphene oxide [GO]) to solve the adsorption problem of positively charged pollutants by LDHs. To prepare this nanocomposite, CoZnAl‐LDH and GO were synthesized by coprecipitation and modified Hummers methods, respectively. After ultrasonic pretreatment, they were combined to produce CoZnAl‐LDH/GO nanocomposite with a smooth and uniform texture which used to remove methylene blue as a cationic model pollutant. The synthesized nanocomposite showed a good adsorption capacity with the maximum adsorption capacity of 169.49 mg/g according to the Langmuir model. The effect of temperature on the adsorption process was surveyed by thermodynamic studies confirming the desirability and the spontaneity of the adsorption process. According to kinetic results, the pseudo‐second‐order model fitted the adsorption process, well. Meanwhile, it was determined that the adsorption process, especially in the beginning, had a high rate and 70% of the pollutant was removed within the first 5 min. Also, the effect of pH on the pollutant removal efficiency was investigated. Finally, the reusability of the nanocomposite was tested. High adsorption capacity and rate, the wide range of operational pH (4–10), and good reusability all suggest that CoZnAl‐LDH/GO is a promising adsorbent for industrial and practical uses.

Development of Electro-Reduced AgNPs/MnO2/rGO Composite toward a Robust Sensor for the Simultaneous Determination of Piroxicam and Ofloxacin

“…Fourier-transform infrared (FTIR) spectroscopy was employed to investigate the surface functional group in the as-synthesized composites, as represented in Figure B. The FT-IR spectrum of the GO sample reveals characteristic peaks centered at 3700–3200, 1734, 1622, 1398, 1217, and 1051 cm –1 , which could be ascribed to the ν OH mode of the O–H groups, CO, skeletal ring stretch, O–H deformation, C–OH stretching, and C–O–C (epoxy group) stretching vibrations. − The peaks arising at 1110 and 607 cm –1 in the sample MnO 2 /GO could be attributed to Mn–O–H and Mn–O vibrations, respectively. , Such hallmarks could be observed in the AgNPs/MnO 2 /ErGO sample, implying the successful synthesis of the desired material. Furthermore, the sample AgNPs/MnO 2 /ErGO witnesses a remarkable decrease in the intensity of the broad peak centering in the region of 3700–3200 cm –1 , suggesting the transformation of GO into rGO nanosheets.…”

Efficient Adsorption of Methylene Blue Using a Hierarchically Structured Metal–Organic Framework Derived from Layered Double Hydroxide

“…The addition of dodecyl sulfate anions remarkably enhanced the affinity of organic/Zn–Al LDHs due to electrostatic attractions between the adsorbate and the surfactants. Similarly, Sharifi et al prepared a CoZnAl-LDH/graphene oxide (GO) nanocomposite via ultrasonic mixing, addressing the challenge of adsorbing positively charged pollutants by LDHs . Wang et al demonstrated a synthetic compound, MgNiCo-LDH@ ZIF-67, as an adsorbent for Congo Red (CR) in water.…”

Application of zirconium modified layered double hydroxide and calcination product for adsorptive removal of phosphate from aqueous solution

“…From the perspective of the significance of water quality and rising utilities of nanotechnology, efforts have been made to discuss different types of water treatment by adsorption using nanoadsorbents 15–17 . LDHs consist of positively charged metallic layers, negatively exchangeable anions, and water molecules 18 . Owing to their unique advantages, such as tunable layers and exchangeable anions, 19 LDHs with a high adsorption capacity and fast removal rate have been widely employed in phosphate adsorption 20 …”