LDH Composites Research Articles

Novel Zn-Al LDHs based S-scheme heterojunction with coral reef-like structure for photocatalytic activation of peroxymonosulfate towards nitenpyram decomposition

The construction of an S-scheme heterojunction is an effective way to enhance the photocatalytic activity of composite materials. Thus, a co-precipitation method is combined with a hydrothermal synthesis method in this study to synthesize an S-scheme heterojunction of Bi2WO6/Ag3PO4/Zn-Al LDH photocatalyst with an exceptional morphology like a coral reef. On this basis, an AP0.5BWLDH0.3/PMS/Vis reaction system is constructed. The prepared Bi2WO6/Ag3PO4/Zn-Al LDH composites present better oxidation performance than pure Bi2WO6, Zn-Al LDH and Ag3PO4, with 100% Nitenpyram (50 mg/L) degraded within 90 min due to the photocatalytic activation of peroxymonosulfate. The significant increase in photocatalytic activity is not only due to the uniformly distributed coral reef-shaped nanostructures but also the extended life of the carrier with strong redox capability through S-scheme heterojunction. During the simulated exposure to sunlight, the internal electric field, optimized energy band structure, as well as coulomb force interaction all contributed to the promotion of the transportation of electron-hole pairs in the Bi2WO6/Ag3PO4/Zn-Al LDH composite. For this reason, electrons and holes have high reducing and oxidizing properties, which make the composites have high redox capacity. Then the radical trapping experiments, ESR testing and XPS analysis were used to verify these results. It was revealed that the S-scheme heterojunction mechanism was suitable for the electron migration in a photocatalyst. This study extends the design and preparation ideas of new S-scheme heterojunction photocatalysts and then proposes effective strategies to solve future water pollution.

Rational design of three-dimensional interlaced frameworks with 2D MXene-Ti3C2Tx and 2D ZnCo bimetallic hydroxide for enhanced sodium-ion capacitors

MXene-Ti3C2Tx is a promising material for next-generation energy storage for sodium-ion capacitors (SICs). However, the attraction between active functional groups and hydrogen bonds on the surface of Ti3C2Tx make the interlayer agglomerate obviously. Herein, we introduce 2D ZnCo bimetallic hydroxide (ZnCo-LDH) to adsorb on Ti3C2Tx nanosheets (Ti3C2Tx/ZnCo-LDH) and form the 3D interlaced porous frameworks, which could stabilize the complex structure and provide flexible ion diffusion channels. The ZnCo-LDH could not only increase the active sites for adsorbing the charges, but also prevent Ti3C2Tx from agglomerating and promote the electron transport kinetics. Benefited from this novel stable structure, Ti3C2Tx/ZnCo-LDH possess a wonderful specific capacitance (644.9 F g−1 at 2 mV s−1) and outstanding rate performance that combine with pseudocapacitance and low resistance. Particularly, the Ti3C2Tx/ZnCo-LDH electrode exhibit an excellent cyclic stability with 95.5% of the initial capacitance after 10000 cycles at 5 A g−1. More significantly, the SICs fabricated with 3D porous Ti3C2Tx/ZnCo-LDH display maximized energy density of 27.2 Wh kg−1 and power density of 7987.5 W kg−1, and an outstanding cycle stability of 95.8% after 10000 cycles. This work could provide an effective strategy for the preparation of MXene and LDH composites as electrode materials for sodium ion capacitors.

SrTiO3@NiFe LDH core-shell composites for photocatalytic CO2 conversion.

A series of core@shell SrTiO3@NiFe LDH composites (STONFs) were synthesized and their photocatalytic CO2 reduction performance was studied. The photocatalyst STONF 2 exhibited enhanced CO2 reduction performance with CO yield of 7.9 μmol g−1 h−1. The yield was 25.7 times and 8.8 times higher than that of NiFe LDH and SrTiO3 respectively, and also higher than most LDH based photocatalysts. Compared with two individual components, STONFs exhibited their combined merits of widened absorption spectrum, higher transportation efficiency and alleviated recombination of e−/h+ pairs. In addition, there were fewer oxygen vacancies in STONF 2 than as-prepared SrTiO3. Lower oxygen vacancies concentration would increase the opportunity of direct bonding between interface atoms of two components and successively increase the electron transportation and separation. These factors synergistically contributed to enhanced photocatalytic performance. This work will provide new insight for designing complementary multi-component photocatalysis systems.

Synthesis and characterization of Co(II)–Co(III) LDH and Ac@Co(II)–Co(III) LDH nanohybrid and study of its application as bactericidal agents

The present study reports the green synthesis of a highly mesoporous Co(II)–Co(III) LDH and its nanohybrid through a sol–gel route with non-aqueous ethanol: acetone mixture as greener reagents. The compounds were characterized using PXRD, FESEM, HRTEM, FTIR, XPS, TGA-DTA, etc. It was observed that the synthesized Co(II)–Co(III) LDH and its nanohybrid showed well-organized LDH structures similar to that of the Mg-Al hydrotalcite material, bearing mesopores and crystalline structures highly as confirmed by PXRD, FESEM, and HRTEM studies.FTIR, XPS, and TGA-DTA studies also showed that the synthesized compounds formed a typical LDH –OH shared construction, containing di and trivalent cobalt with a 3:1 divalent: trivalent LDH ratio, and exhibited a common three-step thermal degradation behavior. Zeta potential and BET analysis showed that the synthesized materials bear a positive charge typical of LDH composition; the surface area and pore volume were found to be 88 m2.g−1and 1.37 cm3.g−1(cobalt LDH), and the intercalated nanohybrid as 169 m2.g−1 and 1.26 cm3/g, respectively.Furthermore, antibacterial evaluation studies using a well-diffusion method, broth serial dilution method (MIC/MBC), and time-kill efficacy test showed the synthesized compounds are effective bactericidal agents against the two bacterial strains viz S. aureus(gram-positive) and E.coli(gram-negative). The results showed that the synthesized Ac@Co(II)–Co(III) LDH nanohybrid showed better activity than Co(II)–Co(III) LDH. The inhibition activity of cobalt LDH and its nanohybrid were found to be higher against E.coli than S.aureus. This higher inhibition activity might be due to the factors like particle size, high surface area, and positively charged active cobalt LDH nanoparticles with acetylacetone molecule, which act on the negatively charged host cell membrane, resulting in the damage of bacterial cell wall.

Ultrafast photodegradation of nitenpyram by Ag/Ag3PO4/Zn–Al LDH composites activated by persulfate system: Removal efficiency, degradation pathway and reaction mechanism

In this study, an investigation is conducted into the degradation of nitenpyram (NTP) using highly efficient APMMO/PDS/Vis system. As photocatalysts, silver phosphate (AP) and calcined Zn–Al layered double hydroxides (MMO) exhibit high efficiency in achieving charge separation. Besides, the injection of electrons into peroxydisulfate (PDS) from the APMMO can contribute to obtaining the species in the active state with higher efficiency. Based on the APMMO/PDS/Vis system, 50 mg/L of nitenpyram (NTP, 50 mL) can be completely removed in 60 min using 0.8 g/L photocatalyst and 0.2 g/L PDS under the optimum condition and visible light (780 nm > λ > 420 nm). Meanwhile, as demonstrated under visible light within 30 min, an ultrahigh degradation efficiency can be achieved by NTP based on APMMO1/PDS/Vis system. Besides, the electron paramagnetic resonance (EPR) technique and radical quenching experiments suggested 1O2, h+, SO4−•, •O2−, and •OH are all contributory to the removal of pollutants. Given the outcomes achieved by LC/MS system and mass spectrometry, the primary degradation intermediates of NTP end up being converted into photodegradation products (such as 2-Chloropyridine, 6-Chloropurine Riboside and dl-Leucine). Additionally, there are three potential photodegradation pathways to NTP degradation have been deployed. Moreover, the NTP light degradation occurring in APMMO1/PDS/Vis system is competent under the three types of real water sample. Accordingly, the high-efficiency APMMO1/PDS/Vis system is fit for use in water pollution control for agricultural productions.

Hierarchical coral-like MnCo2O4.5@Co–Ni LDH composites on Ni foam as promising electrodes for high-performance supercapacitor

Transition metal oxides are generally designed as hybrid nanostructures with high performance for supercapacitors by enjoying the advantages of various electroactive materials. In this paper, a convenient and efficient route had been proposed to prepare hierarchical coral-like MnCo2O4.5@Co–Ni LDH composites on Ni foam, in which MnCo2O4.5 nanowires were enlaced with ultrathin Co–Ni layered double hydroxides nanosheets to achieve high capacity electrodes for supercapacitors. Due to the synergistic effect of shell Co–Ni LDH and core MnCo2O4.5, the outstanding electrochemical performance in three-electrode configuration was triggered (high area capacitance of 5.08 F cm−2 at 3 mA cm−2 and excellent rate capability of maintaining 61.69% at 20 mA cm−2), which is superior to those of MnCo2O4.5, Co–Ni LDH and other metal oxides based composites reported. Meanwhile, the as-prepared hierarchical MnCo2O4.5@Co–Ni LDH electrode delivered improved electrical conductivity than that of pristine MnCo2O4.5. Furthermore, the as-constructed asymmetric supercapacitor using MnCo2O4.5@Co–Ni LDH as positive and activated carbon as negative electrode presented a rather high energy density of 220 μWh cm−2 at 2400 μW cm−2 and extraordinary cycling durability with the 100.0% capacitance retention over 8000 cycles at 20 mA cm−2, demonstrating the best electrochemical performance compared to other asymmetric supercapacitors using metal oxides based composites as positive electrode material. It can be expected that the obtained MnCo2O4.5@Co–Ni LDH could be used as the high performance and cost-effective electrode in supercapacitors.

Magnesium/aluminum layered double hydroxides intercalated with starch for effective adsorptive removal of anionic dyes

In this research, the adsorptive performance of a starch-magnesium/aluminum layered double hydroxide (S-Mg/Al LDH) composite was investigated for different organic dyes in single-component systems by conducting a series of batch mode experiments. S-Mg/Al LDH composite showed preferential adsorption of anionic dyes than cationic dyes. The marked impact of key process variables (e.g., contact time, adsorbent dosage, pH, and temperature) on its adsorption was investigated. Multiple isotherms, kinetics, and thermodynamic models were applied to describe adsorption behavior, diffusion, and uptake rates of the organic dyes over S-Mg/Al LDH composite. A better fitting of the non-linear Langmuir model reflects the predominance of monolayered adsorption of dye molecules on the composite surface. Partition coefficients (mg g−1 μM−1) for S-Mg/Al LDH were observed in the following descending order: Amaranth (665) > Tartrazine (186) > Sunset yellow (71) > Eosin yellow (65). Furthermore, comparative evaluation of the adsorption enthalpy, entropy, and Gibbs free energy values indicates that the adsorption process is spontaneous and exothermic. S-Mg/Al LDH composite maintained a stable adsorption/desorption recycling process over six consecutive cycles with the advantages of low cost, chemical/mechanical stability, and easy recovery. The results of this study are expected to expand the application of modified LDHs toward wastewater treatment.

Improving the reduction and sensing capability of Fe3O4 towards 4-nitrophenol by coupling with ZnO/Fe0/Fe3C/graphitic carbon using ZnFe-LDH@carbon as a template

FeOx-carbon composites are highly active for biomolecule electroanalysis; but not for environmental pollutants such as 4-nitrophenol (4-NP). This is due to the weak electroreduction capability of FeOx towards 4-NP. Herein, we demonstrate that by hybridizing Fe3O4 with ZnO/Fe0/Fe3C/graphitic carbon (g-C) this limitation is mitigated leading to exceptional 4-NP reduction and detection. The Fe3O4/ZnO/Fe0/Fe3C/g-C heterostructure is synthesized via carbothermal reduction of ZnFe-LDH@carbon under N2. The effect of temperature, LDH composition, and g-C on the microstructure and chemical composition of the heterostructure are thoroughly investigated. The presence of ZnO and g-C induce structural pores within Fe3O4/ZnO/Fe0/Fe3C/g-C by preventing the aggregation of Fe3O4 particles which leads to high ECSA and mass transfer. Meanwhile, a temperature > 800 °C is crucial to avoid the inactive ZnFe2O4 phase and transform ZnFe-LDH@carbon fully into Fe3O4/ZnO/Fe0/Fe3C/g-C.The Fe0 site facilitates 4-NP adsorption, while Fe3C acts as a conductive channel for fast electron transfer at Fe2+/Fe3+ redox couple sites in Fe3O4 where 4-NP electroreduction occurs. These properties work in synergy leading to high sensitivity, ultra-low 4-NP detection limit, and selectivity in PBS as well as tap and river water. The results of this study show that the electroanalytical performance of Fe3O4 for environmental pollutants can be tuned by coupling it with the appropriate interface(s).

Three-dimension hierarchical composite via in-situ growth of Zn/Al layered double hydroxide plates onto polyaniline-wrapped carbon sphere for efficient naproxen removal

In this work, a novel adsorbent, 3D hierarchical CS@PANI@ZnAl-LDH composite, has been successfully fabricated through the hydrothermal synthesis of the carbon sphere, oxidative polymerization of polyaniline, and in-site growth of ZnAl-layered double hydroxides, simultaneously applied for the naproxen removal from aqueous solutions. The dynamics and isotherms fit better with the pseudo-second-order and Langmuir model, demonstrating the chemisorption, monolayer, and endothermic process. In addition, the high uptake capacities of CS@PANI@ZnAl-LDH for naproxen was 545.5 mg/g at 298 K when the pH was 5.0, outperforming most previously reported materials. Moreover, after five adsorption-desorption cycles, the spent CS@PANI@ZnAl-LDH maintains high removal efficiency and structural composition, revealing excellent recyclability and stability. Furthermore, Fourier transformed infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) analyses indicate electrostatic interactions, π-π interactions, and hydrogen bonding between CS@APNI@ZnAl-LDH and naproxen. Quantitative analyses, Localized orbit locator (LOL)-π isosurface, and Independent Gradient Model further verify the adsorption mechanisms mentioned above, indicating the synergistic effects between PANI and ZnAl-LDH improve the elimination ability for naproxen. Significantly, Hirshfeld surface analyses reveal that naproxen behaves as the H-bond acceptor, and the ZnAl-LDH acts as the H-bond donor. This work provided a feasible way to design purification materials for wastewater treatment.

Ag-In-Zn-S Quantum Dot-Dominated Interface Kinetics in Ag-In-Zn-S/NiFe LDH Composites toward Efficient Photoassisted Electrocatalytic Water Splitting.

Photoassisted electrocatalysis (P-EC) emerges as a rising star for hydrogen production by embedding photoactive species in electrocatalysts, for which the interfacial structure design and charge transfer kinetics of the multifunctional catalysts remain a great challenge. Herein, Zn-AgIn5S8 quantum dots (ZAIS QDs) were embedded into 2D NiFe layered double hydroxide nanosheets through a simple hydrothermal treatment to form 0D/2D composite catalysts for P-EC. With evidence from transient photovoltage spectroscopy, we acquired a clear and fundamental understanding on the kinetics of charge extraction time and extraction amount in the 0D/2D heterojunctions that was proved to play a key role in P-EC. Upon light illumination, for HER, the optimized NiFe-ZAIS exhibits obviously reduced overpotentials of 129 and 242 mV at current densities of 10 and 50 mA cm-2, which are 22 and 33 mV lower than those of dark electrocatalysis, respectively. For OER, the NiFe-ZAIS electrode also shows low overpotentials of 220 and 268 mV at current densities of 10 and 50 mA cm-2, respectively, under light illumination, which were able to almost double the intrinsic activity. Finally, with NF@NiFe-ZAIS as both the cathode and the anode, the assembled electrolyzer only requires 1.62 V to reach the overall water splitting current density of 10 mA cm-2 under P-EC. This work provides a useful example for the profound understanding of the design and the kinetics study of multifunctional P-EC catalysts.

Application of Biochar Functionalized with Layered Double Hydroxides: Improved Plant Growth Performance after Use as Phosphate Adsorbent

The objective of this study was to verify the feasibility of using biochar, functionalized with layered double hydroxides, as a fertilizer after its use in phosphate treatment (P-BC-LDHs). It was conducted with several levels of P-BC-LDHs using seed germination and early growth assays of lettuce (Lactuca sativa L.). The application of P-BC-LDHs resulted in successful seedling emergence, with an excellent germination capacity of over 96% for all treatments. However, compared to the controls, P-BC-LDHs did not provide favorable seedling traits. In contrast, in the latter experiments, lettuce cultivated under mixtures with P-BC-LDHs, particularly at an application rate of 2.5% (w/w), displayed superior growth quality to those under non-treated conditions. The length of lettuce shoots and roots from this optimal dosage were increased by at least 24% compared to untreated samples. A 17% reduction in biomass yield was observed for the samples from non-supplemented substrates. The nutrient release profiles showed that P-BC-LDHs were capable of slowly supplying phosphorus, thereby increasing the long-term nutrient availability for plants. The findings reported here provide important insights into these materials and confirm that P-BC-LDHs can be used for agricultural purposes after phosphate remediation applications. The results of this study provide constructive information to facilitate the implementation of biochar-based LDH composites for sustainable phosphate removal and recovery.

Effect of Pt(Au)/MgAlOx catalysts composition on their properties in the propane dehydrogenation

A series of bimetallic Au-Pt catalysts were obtained by using MgAl-layered double hydroxides (LDH) as support precursors. Their properties were studied in comparison with monometallic analogs. The effect of the nature of the interlayer anion in LDH composition (CO32−, OH-), Mg/Al ratio in support, platinum and gold content as well as their ratio, on catalytic activity in propane dehydrogenation were studied. The properties of the samples with anchored metal complexes were researched by DRES and XRD. The size of the anchored metal particles was estimated by TEM and CO chemisorption methods.

Flower-like NiMn-layered double hydroxide microspheres coated on biomass-derived 3D honeycomb porous carbon for high-energy hybrid supercapacitors

The efficient utilization of composites derived from the renewable biomass resources could provide a cost-effective alternative for supercapacitor applications. Herein, the honeycomb-like porous carbon conductive scaffold was prepared with biomass Chingma Abutilon seeds as the precursor. Subsequently, NiMn-layered double hydroxide (NiMn LDH) microspheres with pseudocapacitive properties were uniformly supported on the as-prepared carbon nanomaterials in the form of nanosheets. Typically, the highly conductive porous carbon skeleton provided more active sites for fast electron transport and might regulate the growth of the nanosheets. Indeed, the optimal CAS30@NiMn LDH material exhibited a large specific capacity of 1719 F g−1 (1 A g−1) and superior rate stability in the three-electrode configuration, which were relatively higher than the values of pure NiMn-LDH. Moreover, the as-assembled hybrid supercapacitor with CAS30@NiMn LDH composite could deliver a high energy density of 95.29 Wh kg−1 and impressive cycle performance (87 % retention after 5000 cycles).

Biomimetic design of Ni Co LDH composites linked by carbon nanotubes with plant conduction tissues characteristic for hybrid supercapacitors

The instability and poor conductivity of metal-organic frameworks (MOFs) are the main factors limiting its application in supercapacitors. In this paper, inspired by the bionic concept of plant conduction tissue, a unique hierarchical structure with Ni Co layered double hydroxide linked by carbon nanotubes (CNTs/Ni Co LDH) was designed and synthesized for the first time. Among them, the introduction of CNTs can not only transport electrons and ions into the interior of materials, but also can play a role in the connection when the materials break, just like lotus root silk. Furthermore, the phase transition from MOF to LDH can enhance the redox activity of the materials and thus improve the coulomb efficiency. When used as an electrode material, CNTs/Ni Co LDH composites had a superior specific capacitance of 1628 F g−1 at 1 A g−1, and had an enhanced rate capability. The assembled hybrid supercapacitor exhibited a competitive energy density of 38.89 Wh kg−1 at power density of 800 W kg−1, and had a remarkable cyclic stability with a specific capacitance retention of 99.379% for 10,000 cycles at 5 A g−1. This bionic concept of plant conducting tissues can provide a new way to optimize the electrochemical performance of pure MOFs or metal hydroxide materials.

Synthesis of MnO2/Mg-Al layered double hydroxide and evaluation of its NO-removal performance

The removal of toxic nitric oxide (NO) from exhaust gas is challenging and expensive. MnO2/Mg-Al LDH, a composite of manganese dioxide and Mg-Al layered double hydroxide, was synthesized via the rehydration method for potential application in NO removal. MnO2/Mg-Al LDH was found to be complexed with MnO2, pillared between the LDH layers and intercalated with CO32− and OH−. We investigated the performance of a MnO2/Mg-Al LDH treatment in removing NO from exhaust gas. The exhaust gas was circulated in a reaction tube filled with MnO2/Mg-Al LDH, CO3･Mg-Al LDH, or a MnO2 + CO3･Mg-Al LDH mixture, and the NO removal efficiency of the MnO2/Mg-Al LDH composite was compared with that of the other compounds. When NO gas (150 ppm, linear velocity 1.0 m/min) was distributed at 170 °C, treatment with the MnO2･Mg-Al LDH composite and CO3･Mg-Al LDH yielded removal rates of 83.9% and 0%, respectively. The significantly higher NO removal rate of MnO2/Mg-Al LDH was ascribed to the transformation of NO to NO2 via oxidation over MnO2. Further, the NO removal rate after 90 min through the application of a simple mixture of MnO2 and CO3･Mg-Al LDH (Mn: 4.2 wt%) was only 1.4%, suggesting that a synergistic effect was generated by the MnO2/Mg-Al LDH composite. Though NO removal by MnO2/Mg-Al LDH was reduced at temperatures of 140 °C and higher, the results suggest that the synthesized compound can be much more effective than those commonly used for NO removal from exhaust gas.

Biodegradation of Poly (Butylene Succinate) (PBS)/Stearate Modified Magnesium-Aluminium Layered Double Hydroxide Composites under Marine Conditions Prepared via Melt Compounding.

In the present work, polybutylene succinate (PBS)/stearate modified magnesium-aluminium layered double hydroxide (St-Mg-Al LDH) composites were prepared via melt processing and the effect of different loadings of St-Mg-Al LDH on the degradation behaviour of PBS under marine conditions was investigated. The morphological, mechanical and thermal characteristics of the composites were studied using different characterisation techniques. Optical imaging and scanning electron microscopy revealed that the incorporation of St-Mg-Al LDH accelerates the degradation of PBS along with the activity of microorganisms adhered to the composite films. PBS/St-Mg-Al LDH composites are found to have lower thermal degradation temperatures than those of pure PBS. The decrease in thermal stability is correlated with the degradation of PBS due to the catalytic action Mg and Al present in LDH. Tensile and DMA analysis revealed that the addition of St-Mg-Al LDH did not have a significant impact on the mechanical properties of PBS.

Chitosan-Ni/Fe layered double hydroxide composites as an efficient solid phase extraction sorbent for HPLC-PDA monitoring of parabens in personal care products

There is a dire need for development of efficient and sensitive methods to efficiently screen parabens. In this research, we focused on quantification of four parabens (i.e., methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butyl paraben (BP)) using chitosan intercalated nickel/iron layered double hydroxide (CS–Ni/Fe-LDH) composites as solid phase extraction sorbent prior to HPLC-PDA analysis. CS-Ni/Fe LDH composites with a heterogeneous, porous texture, and coral reef-like structure exhibit appealing extraction efficiency for the target parabens due to the enhanced possibility for the formation of hydrogen bonding and hydrophobic interactions. The performance of the composites was assessed and optimized for solid phase extraction of parabens from standard samples and real samples (rose water, cream, toothpaste, hair serum, and sunscreen). The LDH-SPE-HPLC method exhibited a wide linear range (e.g., 100–50,000 ng L−1), good linearity (R2 ≥ 0.999), and good precision (relative standard deviation (RSD) < 3%). This method successfully enriched selected parabens with remarkable recovery above 85.95% and a good RSD (0.01–2.90%). The quantitation of MP, EP, PP, and BP was made at detection range (and limits of detection (LOD)) of 5–15 (9.8), 11–21 (16.2), 6–18 (12.4), and 10–20 (15.6) ng L−1, respectively. The prepared composites also displayed excellent performance with enhanced reusability/durability (n = 30 cycles) and reproducibility (n = 5).

Starch-Mg/Al layered double hydroxide composites as an efficient solid phase extraction sorbent for non-steroidal anti-inflammatory drugs as environmental pollutants

Using a co-precipitation method, starch-Mg/Al layered double hydroxide (S-Mg/Al LDH) composites were synthesized. Their physicochemical properties were assessed by Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and thermo-gravimetric analysis. The quantification of six non-steroidal anti-inflammatory drugs (NSAIDs) was conducted using real samples (e.g., hospital waste water, river water, sewage treatment plant water, and tablet formulations) by gas chromatography-mass spectrometry. For the development of this method, the system was optimized in terms of several key variables (e.g., pH, flow rate, and eluent type/volume). The developed method for NSAIDs exhibited good resolution, sensitivity, reproducibility, and specificity even in complex matrices with limits of detection between 4 and 20 pg/mL. Hence, S-Mg/Al LDH composites were proven to be efficient and fast solid phase extraction (SPE) sorbents for NSAIDs. In addition, each LDH-SPE cartridge showed good reusability without a noticeable change in performance (e.g., up to 30 cycles) and target recoveries between 99.5 – 82.9 %. This work should open up new opportunities for a sesnsitive and sustainable quantitative method for the determination of NSAIDs in complex samples.

Hollow N‐ZIFs@NiCo‐LDH as highly efficient catalysts for 4‐nitrophenol and dyes

N‐ZIF‐(1:0)@NiCo‐LDH, N‐ZIF‐(1:3.5)@NiCo‐LDH and N‐ZIF‐(0:1)@NiCo‐LDH were prepared by mixing solvents in various volume ratios (Vmethanol:Vwater = 1:0, 1:3.5 and 0:1) when synthesizing precursors. These composite materials were characterized using scanning and transmission electron microscopies, X‐ray diffraction, X‐ray photoelectron spectroscopy and nitrogen adsorption–desorption measurements, and investigated as catalysts for reduction of 4‐nitrophenol, methyl orange and methylene blue. The NaBH4 concentration as an important factor that may affect catalytic activity for reduction of 4‐nitrophenol was examined. Under optimal experimental conditions, the excellent catalytic activity of the N‐ZIF‐(0:1)@NiCo‐LDH composite, compared to that of N‐ZIF‐(1:0)@NiCo‐LDH and N‐ZIF‐(1:3.5)@NiCo‐LDH composites, could be attributed to the presence of graphitic nitrogen. In addition, compared with previously reported catalysts, all catalysts prepared show excellent catalytic activity owing to the unique structure exposing more active sites.

The treatment of Raw Water Sources of Drinking Water using Chitosan/Mg/Al–LDH Composites: Problem cases in Municipal Waterworks in Banjarmasin

A study was done on treatment of raw water sources for drinking water using chitosan/Mg-Al LDH (CS/Mg/Al–LDH) composites by adsorption process. An analysis on the adsorbent characterizations of FTIR, SEM and XRF showed that the CS/Mg/Al–LDH had many different functional groups and a high specific surface area for adsorption processes. The CS/Mg/Al–LDH showed high adsorption uptake capacity and selectivity for iron (Fe), turbidity, and colour in the raw water sources for drinking water in Municipal Waterworks in Banjarmasin. Therefore, the CS/Mg/Al–LDH composites have the potential to be used as an adsorbent in water and wastewater treatment.