NiAl-layered Double Hydroxide Research Articles

Synergistic Effect of NiAl-Layered Double Hydroxide and Cu-MOF for the Enhanced Photocatalytic Degradation of Methyl Orange and Antibacterial Properties

This study synthesized NiAl-layered double hydroxide (LDH)/Cu-MOF photocatalyst using a simple impregnation method involving NiAl-LDH and Cu-MOF. The successful synthesis was confirmed through Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), zeta potential measurements, thermogravimetric analysis (TGA), ultraviolet diffuse reflectance spectroscopy (UV-DRS), N2 adsorption at −196 °C, and electrochemical impedance spectroscopy (EIS). Photocatalysts based on NiAl-LDH, Cu-MOF, and NiAl-LDH/Cu-MOF were used to remove methyl orange (MO) dye from contaminated water. The impact of various factors, including pH, dye concentration, and photocatalyst amount, on MO degradation efficiency was assessed. FTIR analysis was conducted both before and after dye degradation. The optimal degradation conditions were a photocatalyst dose of 25 mg and a pH of 3. Kinetic studies indicated that the degradation of MO dye onto NiAl-LDH/Cu-MOF followed a pseudo-first-order and an L–H or Langmuir–Hinshelwood model. The value of R2 = 0.94 confirms the validity of pseudo-first-order and Langmuir–Hinshelwood (L–H) kinetic models for the photocatalytic degradation of MO dye. This study highlights the importance of developing novel photocatalysts with improved degradation efficiency to protect the water environment. Antibacterial activity was also performed with antibacterial sensibility testing by disk diffusion to determine minimal inhibitory and bactericidal concentrations. In short, NiAl-LDH/Cu-MOF can be helpful for various biomedical and industrial applications.

Ultrasensitive Detection of Trace Silver Ions Using MoS42--Intercalated LDH Nanosheets Enhanced SPR Sensor.

The widespread use of silver raises concerns about environmental and health risks, necessitating highly sensitive detection methods for trace silver ions (Ag+). Surface plasmon resonance (SPR) sensors offer benefits like label-free detection and rapid response, but their sensitivity for Ag+ detection is limited due to weak ion adsorption. Here, we developed an SPR sensor with MoS42--intercalated NiAl-layered double hydroxide (LDH) as the adsorption layer of Ag+ to enhance detection sensitivity. Our sensor achieves a sensitivity of 254.75 nm/μg/L and detects Ag+ at a low concentration of 2.8 pM, outperforming various existing sensors. It also shows excellent repeatability, long-term stability, and selectivity, proving effective in real-world environmental samples. This work advances high-performance SPR sensors for heavy metal ion detection.

Preparation of La-doped NiAl-LDH with boosted electron transfer for the enhanced photocatalytic activity of tetracycline: Performance evaluation, degradation pathway, and mechanism insight

Developing a photocatalysis-based system is an effective strategy for removing antibiotics. Herein, La-doped NiAl-layered double hydroxides (LaNiAl-LDH) photocatalyst was synthesized using a chemical co-precipitation-hydrothermal method. The prepared samples were characterized by various advanced analyses and investigated for the photocatalytic degradation of tetracycline (TC). The crystalline phase and functional groups of the synthesized samples were successfully confirmed by XRD and FTIR analyses. By doping La into NiAl-LDH structure, the band gap was reduced from 3.01 eV to 2.57 eV, indicating higher photocatalytic activity of 1% LaNiAl-LDH. The surface morphology of the synthesized samples shows the formation of nanosheets in the structure of LDH. Under the optimum status ([TC]0 = 10 mg/L, [1% LaNiAl-LDH] = 0.2 g/L, and pH = 6), the photocatalytic activity of 1% LaNiAl-LDH (84.85%) was higher than NiAl-LDH (71.52%) within 90 min reaction. This difference can be attributed to the presence of La sites in 1% LaNiAl-LDH which act as electron-transfer mediators, leading to a significant improvement in the separation of photogenerated charge carriers. The effect of the addition of various scavengers was evaluated. Moreover, using the o-phenylenediamine (OPD), and photoluminescence (PL) analysis, the formation of •OH radicals was supported. The higher charge-transfer efficiency of 1% LaNiAl-LDH was confirmed by photoelectrochemical analysis. Furthermore, the reusability, stability, and degradation pathway of the as-synthesized nanocomposite were systematically examined. This work presents guidance for applying doped LDH-based materials in photocatalysis and promising applications in wastewater remediation.

Controlling charge migration and CO2 conversion through surface decoration of 2D-hydrotalcite on bismuth oxybromide for enhanced artificial photosynthesis

Photocatalytic reduction of CO2 in pure H2O media to produce chemicals presents an appealing avenue for simultaneously alleviating energy and environmental crises. However, the rapid recombination of photogenerated charge carriers presents a significant challenge in this promising field. Heterojunction engineering has emerged as an effective approach to address this dilemma. Here, by decorating 2D NiAl-layered double hydroxides (NAL) onto bismuth oxybromide (BOB), we have created a S-scheme heterojunction (N1B1 composite). This catalyst affords CO2-to-CO yields of 102.30 μmol g−1 with a selectivity of 100 %. Ultraviolet photoelectron spectroscopy (UPS) and in-situ irradiated X-ray photoelectron spectroscopy (ISI-XPS) reveal that charge transfer occurs efficiently from BOB to 2D-NAL upon light irradiation. The designed N1B1 heterojunction achieves 7.3-fold and 2.1-fold increase in the internal electric field strength compared to bare 2D-NAL and BOB, respectively, which should be accountable for the improved charge migration. Additionally, pulsed chemisorption and in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) show the presence of multiple carbonate intermediates with activated OCO bonds upon N1B1 composite, with *CO2− being identified as the most crucial species for CO production.

NiAl-LDHs-derived NiO/Al2O3 with high specific surface area for wide range hydrogen detection

The construction of heterojunctions is generally considered as one of the effective strategies to improve gas sensing performance. Herein, the NiO/Al2O3 (NAO) hybrid structure is constructed by calcining Ni–Al layered double hydroxides (NiAl-LDHs). The specific surface area and pore size of NAO are effectively regulated by changing the content of NaOH. The XPS and BET characterization results indicate that NAO-5 exhibits a high oxygen vacancy content, a large specific surface area (468.524 m2 g−1), and abundant pore size. The hydrogen (H2) sensitivity property of NAO was investigated, and NAO-5 exhibited outstanding gas sensing performance to 500 ppm H2 at 370 °C, including high response (10.524), fast response recovery speed (21 and 30 s), and wide detection range (0.1–5000 ppm). The improved gas property is mainly attributed to the increased oxygen vacancies and specific surface area. This study provides a feasible approach for NiAl-LDHs in H2 monitoring and early warning.

Photocatalytic CO2 Reduction by Near-Infrared-Light (1200 nm) Irradiation and a Ruthenium-Intercalated NiAl-Layered Double Hydroxide.

Near-infrared light-driven photocatalytic CO2 reduction (NIR-CO2PR) holds tremendous promise for the production of valuable commodity chemicals and fuels. However, designing photocatalysts capable of reducing CO2 with low energy NIR photons remains challenging. Herein, a novel NIR-driven photocatalyst comprising an anionic Ru complex intercalated between NiAl-layered double hydroxide nanosheets (NiAl-Ru-LDH) is shown to deliver efficient CO2 photoreduction (0.887 μmol h-1) with CO selectivity of 84.81 % under 1200 nm illumination and excellent stability over 50 testing cycles. This remarkable performance results from the intercalated Ru complex lowering the LDH band gap (0.98 eV) via a compression-related charge redistribution phenomenon. Furthermore, transient absorption spectroscopy data verified light-induced electron transfer from the Ru complex towards the LDH sheets, increasing the availability of electrons to drive CO2PR. The presence of hydroxyl defects in the LDH sheets promotes the adsorption of CO2 molecules and lowers the energy barriers for NIR-CO2PR to CO. To our knowledge, this is one of the first reports of NIR-CO2PR at wavelengths up to 1200 nm in LDH-based photocatalyst systems.

Syntheses of Ni-Based Layered-Double Hydroxide Materials Via Liquid Phase Deposition Method for Alkaline Water Electrolysis

For the sustainable society, hydrogen production has received much attention during decades. The alkaline water electrolysis process has been recognized as one of the important processes for hydrogen products. For the achievements of an effective water electrolysis system, the decrease of the overpotential on the oxygen evolution reaction (OER), which is the four-electron and proton transfer process. These complex 4-electron sluggish processes lead to the large energy losses in the whole water electrolysis. Although the noble catalysts such as IrO2 or RuO2 exhibit high OER activity, their large-scale applications are limited due to cost problem. From this point of view, the low-cost transition metal materials, especially Ni-based catalysts, have been extensively studied. And also, it has been reported that the well-defined layered double hydroxide (LDH) structures can promote water oxidation through the interlayer anion effects. Despite this fact, the specific procedures for the preparation of Ni-based LDH structures have not been well established. Therefore, in this study, we have investigated the preparation of Ni-based LDH structures in the aqueous solution at room temperature, the so-called liquid phased deposition (LPD) method.Through the LPD method, we have synthesized various types of Ni-based LDH structures. As an example, the Ni-Al LDH structures were synthesized on the conductive substrate. It was found that our synthesized Ni-Al LDH exhibited relatively high OER activity and durability against electrochemical potential cycling [1]. In addition, the dependencies of the OER activity on the interlayer anion species were clearly demonstrated. In addition, the other types of Ni alloy LDHs were also prepared and their OER activity was investigated. Through the electrochemical measurements, we have confirmed the advantages of our materials prepared by LPD methods as an anode for alkaline water electrolysis.

Humidity sensitive memristor based on Ni–Al layered double hydroxides

Reaping the advantages of their exceptional humidity-sensitive elements, humidity sensors exhibit a remarkable ability to adapt to alterations in ambient moisture levels. The significance of the humidity sensor in biological detection is progressively growing, owing to this characteristic. This work examines the impact of humidity on the resistive switching properties Ni–Al layered double hydroxides (LDHs) memristor. As the porous Ni–Al LDHs material contains a significant number of hydroxyl groups, the Ni–Al LDHs memristor exhibits remarkable sensitivity to changes in humidity. As the relative humidity level increases, a conspicuous decrease is observed in resistance of low resistance state, which attributed to the transition of protons facilitated by water. The humidity detection range of the Ni–Al LDHs memristor is from 30 RH% to 95 RH%, and it exhibits a sensitivity of 101.72 mV/RH. The Ni–Al LDHs memristor exhibits humidity sensitive resistive switching characteristics. In different humidity environments can produce a dynamic change between high and low resistance state switching. An artificial humidity sensing system by utilizing the unique resistance change behavior in Ni–Al LDHs memristor induced by humidity was demonstrated.

NiAl LDH nanosheets based on Ag nanoparticles-decoration and alkali etching strategies for high performance supercapacitors

Layered double hydroxides (LDHs) represent a category of two-dimensional layered intercalation materials, showing significant potential as electrode materials for the production of high-energy-density supercapacitors due to their tunable composition, ease of synthetic modification, and low cost. Here, we constructed alkali-etched NiAl LDH-OH nanosheets/Ag nanoparticles (NPs) composite material (Ag@NiAl LDH-OH) for high-performance supercapacitors through a simple solvent-thermal reaction. The alkali treatment is employed to selectively etch some Al3+ ions, generating cation vacancies as active sites for energy storage. Additionally, under the simultaneous influence of strong alkalis and vacancies, the interlayer spacing of LDHs expands, aiding in the promotion of interlayer ion mobility. Meanwhile, the decoration of silver nanoparticles ensures excellent electron conductivity in the NiAl-LDH-OH nanosheets, thereby facilitating improved utilization of the active substance and achieving outstanding rate performance. The Ag@NiAl LDH-OH electrode, when prepared, demonstrates a significant increase in specific capacitance, reaching 1790 F g−1 at a current density of 1 A g−1. This represents approximately 7 times the specific capacitance of the pristine NiAl LDH electrode, with a capacity retention of 79 % even under a high current density of 20 A g−1. Moreover, the assembled asymmetric supercapacitor (ASC) attains a maximum energy density of 138.25 Wh kg−1 at a power density of 700 W kg−1, maintaining 81 % of its initial specific capacitance after 20000 cycles. This research introduces novel pathways for advancing high-energy-density SCs.

High stability and selectivity of butterfly pea flower extract-NiAl LDH-based catalysts in the tetracycline degradation.

Layered double hydroxide (LDH) is an applicable material that can be modified in various ways. Modifications using natural extracts fulfill the principles of "green chemistry." The preparation of butterfly pea flower extract (BPE)-modified NiAl LDH was completed using the calcination and restacking method. The characteristics of the prepared composites were identified through analysis of functional groups, crystal phase, bandgap energy, surface area and surface morphology. Fourier transform-infrared (FT-IR) characterization revealed that the active group of the catalyst is -OH except for NiAl layered double oxide (LDO), which has the metal oxide-like functional groups. X-ray diffraction patterns expressed a typical layered material structure of NiAl LDH dan NiAl LDH-BPE, but not for NiAl LDO and NiAl LDO-BPE. Introducing BPE into NiAl LDH and NiAl LDO effectively decreased the bandgap energy and changed the surface morphology. The prepared catalysts were applied in a batch system with pH 5 to degrade tetracycline (TC). NiAl LDO demonstrated the highest activity as a catalyst in TC degradation, with a 93.61% degradation rate. In contrast, NiAl LDO-BPE demonstrated the highest structural stability in TC degradation and repeated use, with an initial degradation percentage of 82.58% and a fifth regeneration percentage of 71.4%.

Custard apple seed oil-based polyesteramide polyol- a precursor for layered double hydroxide (LDH)-modified polyurethane coatings

Polyesteramide polyol was synthesized by employing aminolysis with a base catalyst with custard apple seed oil as source material. It was afterward esterified with phthalic anhydride to form polyesteramide polyol. Polyurethane coatings are produced by combining polyesteramide polyols, which are synthesized, with hexamethylene diisocyanate trimer (HDI). The co-precipitation technique was used to synthesize a nickel-aluminum layered double hydroxide (Ni-Al LDH). Subsequently, the synthesized Ni-Al LDH was further modified by incorporating the corrosion inhibitor 2-mercaptobenzothiazole (MBT) into its interlayer space by the in-situ method. The synthesized Ni-Al LDH and Ni-Al-MBT LDH are then incorporated into the polyesteramide polyol to enhance the anti-corrosive properties of the polyurethane coatings. The synthesized diethanolamide, polyesteramide polyol, and LDH have been characterized using FTIR whereas SEM and XRD are specific to LDH analysis. EIS, DSC, TGA, salt spray, contact angle, and mechanical testing such as thickness, adhesion flexibility, scratch hardness, impact resistance, and pencil hardness are focused on coating evaluation. The incorporation of LDH led to a substantial enhancement in the coating's corrosion resistance, as evidenced by a decrease in corrosion. Incorporating LDH and MBT-LDH improved the scratch resistance of the coating by 1.5 kg compared to plain PU coating, whereas hardness properties also improved slightly. In anticorrosive analysis, it is observed that LDH and MBT-LDH show better anticorrosive performance as compared to plain PU coating.

V2O5-assembled NiAl-layered double hydroxide as high-performance electrode for asymmetric supercapacitor

V2O5-assembled NiAl-layered double hydroxide as high-performance electrode for asymmetric supercapacitor

Investigation of Ag nanoparticles decorated Ni-Al layered double hydroxide as a gas sensor

Chemiresistive gas sensors based on LDH structure were investigated for the detection of widely used volatile organic compounds (VOCs) including methanol, ethanol, and acetone at room temperature. In order to increase the surface active sites and subsequently improve the detection sensitivity of gas molecules, the use of Ag decoration method along with the creation of porosity on the surface of LDH structures were investigated. In this method, methanol solvent was used as a hole scavenger and UV radiation as a catalyst for binding Ag to the surface of LDH sheets. The microstructure and morphology of the composites were investigated by FESEM, HRTEM, EDS, EDS mapping, XRD, and MS analysis. The investigated parameters included relative humidity, calibration curve, repeatability, selectivity, and response/recovery times. According to the obtained results, the creations of surface corrosion by methanol and decorating the structure with Ag have both affected the sensitivity of the sensors. The pure Ni-Al LDH sensor has a response value of 6.8–250 ppm of ethanol. By increasing the specific surface area and creating LDH nanosheets, the response value can be increased up to 8.52. Also, the addition of Ag NP (Ni-Al LDH decorated with Ag NP) has increased the response up to 10.89. It was also observed that the response times in different modes have the least difference. At the end, the response mechanism was investigated based on the heterojunction theory.

Breakthrough Study of CO2 Adsorption and Regeneration Performance of Mn‐ and Ce‐Doped Ni–Al Layered Double Hydroxides Derived Mixed Oxides in Packed‐Bed Column

AbstractCarbon dioxide (CO2) capture is an important strategy to mitigate greenhouse gas emissions and reduce global warming effects. This study synthesizes two nanomaterials, Ce‐doped Ni–Al mixed metal oxide (CNAO) and Mn‐doped Ni–Al mixed metal oxide (MNAO), from Mn‐ and Ce‐doped Ni–Al‐layered double hydroxides using a co‐precipitation method followed by a calcination process. The materials are characterized using various techniques, such as High‐resolution transmission electron microscopy‐energy dispersive x‐ray spectroscopy/selected area electron dispersion (HRTEM‐EDS/SAED), X‐ray diffraction (XRD), x‐ray photoelectron spectroscopy (XPS), Brunauer‐Emmett‐Teller (BET), and attenuated total reflection Fourier transform infrared (ATR FT‐IR). The CO2 adsorption performance of the materials is evaluated using packed‐bed column experiments at the testing conditions of 13 vol% ± 1 vol% CO2 in N2 simulated flue gas, flow rate of 20 mL min−1, inlet pressure of 14.15 ± 0.1 psi, and temperature of 31 °C ± 2 °C. The results show that both CNAO and MNAO are promising nanomaterials for CO2 capture applications due to their high CO2 adsorption capacity and efficiency. CNAO has a higher saturation capacity of 11.4 mmol g−1 and a longer breakthrough time than MNAO, which has a saturation capacity of 10.0 mmol g−1. The doping of Ce and Mn enhances the CO2 adsorption capacity of the materials compared to the un‐doped Ni–Al mixed oxide. The mechanisms of CO2 adsorption are mainly linearly adsorbed CO2, bidentate, and monodentate or bulk carbonate formation, as revealed by ATR FT‐IR analysis. The regeneration performance results suggest that CNAO is more stable than MNAO under multiple regeneration cycles and more promising material for large‐scale CO2 capture applications.

Alkali-etched ultrathin NiAl-layered double hydroxides with rich vacancies for the sensitive electrochemical detection of dopamine

Defect engineering is an effective solution to improve the catalytic performance by liberating edge active sites. Herein, we report the synthesis of porous and ultrathin NiAl-layered double hydroxide nanosheets with rich defects (ELDHe) through the alkali etching followed by liquid delamination of the bulk NiAl-LDH. Etching and delamination actions introduce abundant defects and pores on the ultrathin LDH nanosheets, which can offer numerous edge sites, large specific surface area, and lots of vacancies. Consequently, the ELDHe modified glassy carbon electrode (ELDHe/GCE) realizes fast charge-transfer and mass-transfer on the electrode/electrolyte interface due to the more active centers and large surface area of ELDHe. The modified electrode presents excellent sensing performance toward dopamine. The chronoamperometric sensor achieves a large linear range of 0.05 ∼ 180 μM to dopamine with a detect limit of 6.1 nM. This sensor demonstrates good selectivity, reproducibility, and stability. The corresponding analytical method is successfully applied for the determination of dopamine in human urine samples.

Photocatalytic degradation of reactive dyes over Ni[sbnd]Al layered double hydroxide

Due to the uncontrolled discharge of textile effluents, the extent of reactive dyes in wastewater is rising. Due to their toxicity, efficient removal becomes quite essential. In this report, NiAl layered double hydroxide (LDH) has been prepared using the coprecipitation methodology for the photocatalytic degradation of reactive dyes. The as-prepared materials were characterized by different techniques, such as DRS, XRD, FESEM, HRTEM, and XPS etc. The XRD pattern of the LDH confirms the formation of the rhombohedral (R3m) phase. The FESEM analysis reveals the irregular hexagon-like shape of the prepared LDH. The NiAl LDH has 98(1) and 87(1)% photodegradation efficiencies towards the removal of reactive blue 19 and reactive Red 120, respectively. The control experiments in the presence of different scavengers confirm that hydroxyl radicals and superoxide anions participate in photocatalytic degradation. The HRMS studies confirm the formation of different smaller fragments, thereby providing a deeper insight into the photodegradation mechanism. Moreover, the demineralization efficiency (88.9%) is quite close to the degradation efficiency for reactive blue 19, signifying practically complete demineralization of the pollutants. The recyclability studies ascertain the high stability of the photocatalyst. Therefore, the as-prepared NiAl LDHs can be considered a promising photocatalyst for the removal of reactive dyes from wastewater.

Construction of MoS42− intercalated NiAl-layered double hydroxide by solvent-free method for promoting photocatalytic degradation of antibiotics: Synergistic effect of oxygen vacancies and electron-rich groups

MoS42− intercalated NiAl-layered double hydroxides (LDH) were prepared by solvent-free techniques, which possessed oxygen vacancies and efficient electron transfer channels. Oxygen vacancies were increased with increasing of the MoS42− intercalation amount. Through X-ray Photoelectron Spectroscopy (XPS), Electron Paramagnetic Resonance (EPR), Kelvin Probe Force Microscopy (KPFM), and Density Functional Theory (DFT), the presence of oxygen vacancies and electron transfer channels were confirmed. In the meantime, the formation mechanisms of electron transfer channels and the synergistic mechanisms involving oxygen vacancies and electron transfer channels were illustrated. Electrochemical characterization revealed that compared with LDH, the electron lifetime of LDH-WM-0.5 increased from 1.70 ns to 2.88 ns, and the recombination efficiency of electron holes was reduced by about 6 times. Degradation experiments demonstrated that the degradation rate of tetracycline by LDH-WM-0.5 increased from 19.0 % to 90.0 % in 3 h, representing a 4.5-fold improvement compared to LDH photocatalysts. This study contributed novel insights into developing advanced photocatalysts by strategically manipulating the presence of oxygen vacancies and constructing the electron transfer channels.

An S-scheme heterointerface-engineered high-performance ternary NiAl-LDH@TiO2/Ti3C2 MXene photocatalytic system for solar-powered CO2 reduction to produce energy-rich fuels

While there is much potential for photocatalytic CO2 reduction, poor light absorption and high recombination rates of photogenerated charges limit its effectiveness. To address these challenges, we systematically developed a heterointerface-engineered ternary hybrid photocatalyst comprising NiAl-layered double hydroxide (LDH), titanium dioxide (TiO2), and titanium carbide (Ti3C2) MXene via an in situ growth approach. As a result of the unique combination of these three components, the synthesized ternary NiAl-LDH@TiO2/Ti3C2 photocatalyst demonstrated broad light absorption spanning across the ultraviolet, visible, and near-infrared regions, as well as elevated CO2 adsorption capacity. In situ-irradiated X-ray photoelectron spectroscopy and electron paramagnetic resonance analyses provided compelling evidence for an unconventional S-scheme charge transfer mechanism in the ternary system that effectively separates the charges and suppresses recombination, allowing NiAl-LDH to maintain its strong reducing capacity and TiO2 to maintain its robust oxidizing capacity. Utilizing the complementary and synergistic properties of these three components (NiAl-LDH, TiO2, and Ti3C2), an optimized ternary NiAl-LDH@TiO2/Ti3C2 photocatalyst with 30 wt% Ti3C2 exhibited extraordinary solar-driven CO2 reduction performance with a remarkable 99 % CO selectivity against competitive H2 production and a high apparent quantum yield of 0.81 at 365 nm. Additionally, the ternary photocatalyst exhibited excellent stability, maintaining its performance capacity over multiple CO2 reduction cycles. This work provides a fresh perspective on designing and creating efficient ternary S-scheme photocatalytic systems for solar-driven CO2 reduction and highlights the potential for energy-rich fuel production.

Superior adsorptive removal of ciprofloxacin by graphene oxide modified Ni-Al layered double hydroxide composites

Pharmaceutical drug removal from industrial wastewater has become a major challenge in recent years. To address this concern, an eco-friendly, non-toxic, renewable, low-cost, and simple-to-synthesize catalyst called Ni-Al LDH (Layered Double Hydroxide) was synthesized using the co-precipitation method. LDH was further constructed with GO (Graphene Oxide) using the electro-self-assembly method for its effective performance in the removal of ciprofloxacin from wastewater. XRD, FESEM, EDX, Raman, FTIR, UV-Vis DRS, and BET analysis were used to characterize the as-prepared Ni-Al LDH and composites of GO@LDH. Using bare LDH and its composite with GO, several parameters such as adsorbent dosage, contact time, adsorbate concentration, and pH were optimized. GO(5)@LDH shows complete adsorption of 87.4% in 180 min for ciprofloxacin solution. The SBET for Ni-Al LDH, GO(1)@LDH, and GO(5)@LDH was determined to be in the order 3.5456 m2/g, 19.575 m2/g, and 22.5591 m2/g, suggesting that the surface area of the LDH increases upon GO loading. According to the calculation based on Langmuir isotherm, GO(5)@LDH (1968.5 mg/g) has a greater maximum adsorption capacity than Ni-Al LDH (332.2 mg/g). The kinetic analysis reveals that it adheres to a pseudo-second-order kinetic model. The catalyst was effectively employed for four repeating cycles with only a 10% decrease in removal rate, demonstrating that it can be easily regenerated. The morphology of the catalyst GO(5)@LDH remained the same before and after use, as seen by the XRD spectra, indicating the stability of the catalyst. As a result, LDH-GO composites are ideal catalysts for the treatment of ciprofloxacin wastes in the environment.

Treatment of Methylene Blue Using Ni-Al/Magnetite Biochar Layered Double Hydroxides Composite by Adsorption

Methylene blue dye is hard to degrade and requires treatment using Ni-Al Layered double hydroxides (LDHs) modified with magnetite biochar (MBC) to form Ni-Al/magnetite biochar composite in overcoming environmental pollution. Material attainment was identified by characterization using X-Ray Diffraction (XRD), Fourier Transform – Infra Red (FT-IR), Branuer Emmet Teller (BET), Scanning Electron Microscopy – Energy Dispersive X-Ray (SEM-EDX) and Vibration Sample Magnetometer (VSM). XRD characterization displays angle 2θ at 11°, 60° is a typical angle of LDH, and angles 22° and 35° of magnetite biochar. FT-IR characterization analysis at wavelength 1381 cm-1 for NO3- group and M-O group at wave number 700 cm-1. C-H group on biochar at 1404 cm-1 and wave number 586 cm-1 for Fe-O group. BET characterization analysis of Ni-Al/MBC has a large surface area and pore volume of 127.310 m²/g and 0.1950 cm³/g. SEM characterization analysis of Ni-Al/MBC has large, coarse pores and non-uniform shape, EDX data shows that there are forming elements such as Ni, Al from LDH and, Fe, C elements from magnetite biochar. pH, kinetics, isotherms, and thermodynamics become influential in adsorption processes. The adsorption capacity of the composite reaches 68.493 mg/g by following the Langmuir equation and adsorption kinetics refers to the Pseudo Second Order (PSO) equation. Adsorption continuity is spontaneous and endothermic. Ni-Al/MBC has stability in the process of adsorbent regeneration up to five adsorption cycles and, therefore can be used as a potential adsorbent in the treatment of methylene blue dye in aqueous environmental pollution. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).