Ultrasonic-assisted Co-precipitation Research Articles

Auto-combustion synthesis and characterization of La2CrMnO6/g-C3N4 nanocomposites in the presence trimesic acid as organic fuel with enhanced photocatalytic activity towards removal of toxic contaminates

Constructing semiconductor materials based on layered graphitic carbon nitride (g-C3N4) and metal oxides can help in extending the lifetime of charge carriers and aid in resolving the low number of active sites on their surface for light-driven processes. Herein, we initially designed La2CrMnO6 nanostructures through trimesic acid-assisted auto-combustion route and subsequently, La2CrMnO6/g-C3N4 nanocomposites were prepared by ultrasonic-assisted co-precipitation method with improved UV-catalytic performance. The shape, size distribution and various properties of nano-sized products were measured via diverse description systems of microscopic and spectroscopic. The photocatalytic performances of the La2CrMnO6 nanoparticles and La2CrMnO6/g-C3N4 nanocomposites were compared by degradation of artificial dyes under the UV-light region. Besides, the impacts of dye type, diverse weight percentages of g-C3N4:La2CrMnO6 in composite, scavenger kind and dye solution concentration were studied on modifying ability of nano-catalyst utility. The outcomes manifested La2CrMnO6/g-C3N4 (80:20) nanocomposites have the greatest efficiency, where the highest MO decomposition of 80.98 % was achieved at 10 ppm within 90 min of irradiation. Moreover, the feasible mechanism of MO elimination by UV catalytic purpose was considered.

Design and fabrication of graphitic carbon nitride incorporated zinc silicate hybrid nanocomposite for effective degradation of eriochrome black T dye as water pollutant under sunlight irradiations

This paper presents an approach to prepare zinc silicate (Zn2SiO4) and its nanocomposites with graphitic carbon nitride (g-C3N4) for enhanced photocatalytic performance. Zn2SiO4 was synthesized using a simple and cost-effective sonochemical method, followed by the fabrication of Zn2SiO4/g-C3N4 through an ultrasonic-assisted co-precipitation method. The characterization of Zn2SiO4 and its nanocomposites was carried out using various techniques such as XRD, FTIR, EDS, SEM, TEM, BET, and DRS. The main focus of this study was to investigate the photocatalytic efficiency of g-C3N4, Zn2SiO4, and different Zn2SiO4 nanocomposites for the degradation of eriochrome black T (EBT) and erythrosine (ER). It is worth noting that this is the first time Zn2SiO4 has been combined with carbon nitride, which resulted in excellent photocatalytic performance. The experimental results revealed that several factors influenced the efficiency of the photocatalytic process, including the content of Zn2SiO4 in the nanocomposite, catalyst loading, and initial concentration of EBT. Among all the tested compositions, Zn2SiO4/g-C3N4 with 10 % Zn2SiO4 exhibited the best performance. Specifically, when 70 mg of 10 % Zn2SiO4/g-C3N4 was used as a catalyst, it achieved a remarkable degradation efficiency of 75.5 % for 10 ppm EBT. This finding highlights the potential application of Zn2SiO4/g-C3N4 nanocomposites as efficient photocatalysts for environmental remediation. The results of scavenger test indicated that superoxide radicals and positive holes played significant roles in driving the photodegradation reactions. Furthermore, a kinetics study was performed to determine the rate constant (k) associated with the photocatalytic process. It was observed that a higher rate constant (k = 0.011 min−1) corresponded to a higher efficiency of 75.5 %. This finding suggests that the Zn2SiO4/g-C3N4 nanocomposites possess excellent photocatalytic activity and can effectively degrade organic pollutants.

An ultra-sensitive SARS-CoV-2 antigen optical biosensor based on angiotensin converting enzyme 2 (ACE-2) functionalized magnetic-fluorescent silica nanoparticles.

This work reports on the design and synthesis of an angiotensin-converting enzyme 2 (ACE-2) functionalized magnetic fluorescent silica nanoparticles (Fe-FSNP) as a biosensing platform to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen. Iron oxide (Fe3O4) nanoparticles were synthesized via ultrasonic-assisted coprecipitation and then coated with fluorescent silica nanoparticles (FSNP) through thesol-gelmethod forming the Fe-FSNP samples. Silica obtained from local geothermal powerplant was used in this work and Rhodamine B was chosen as the incorporated fluorescent dye, hence this reports for the first time ACE-2 was immobilized on the natural silica surface. The Fe-FSNP nanoparticle consists of a 18-25 nm magnetic core and a silica shell with a thickness of 30 nm as confirmed from the transmission electron microscopy image. Successful surface functionalization of the Fe-FSNP with ACE-2 as bioreceptor was conducted through hydrosylilation reaction and confirmed through the Fourier transform infrared spectroscopy. The detection of SARS-Cov-2 antigen by Fe-FSNP/ACE2 was measured through the change in its maximum fluorescence intensity at 588 nm where fluorescence- quenching had occurred. The biosensing platform showed a rapid response at 30 min with a linear range of 10-6to 10-2μg ml-1. The magnetic-fluorescent properties of the nanoparticle enables an ultra-sensitive detection of SARS-Cov-2 antigen with the limit of detection as low as 2 fg ml-1.

Synthesis and characterization of Fe2SiO4/Fe2O3/g-C3N4 ternary heterojunction photocatalyst with enhanced photocatalytic activity under visible light

Ultrasonic-assisted co-precipitation is used for the first time to prepare Z-scheme Fe2SiO4/Fe2O3/g-C3N4 ternary heterojunction photocatalysts. Their morphology, crystal structure, specific surface area, optical properties, composition, and photocatalytic behavior have been thoroughly examined. When compared to single-component and binary Fe2SiO4/Fe2O3 heterojunction photocatalysts, ternary Fe2SiO4/Fe2O3/g-C3N4 heterojunction photocatalysts exhibit the most profitable performance for degradation of erythrosine under simulated light. It is likely that this is due to the high rate of separation migration of photoexcited charge carriers, the formation of Z-scheme heterojunction, and the specific surface area. Based on the results of active species trapping experiments, a possible Z-scheme mechanism could explain the significantly reduced photocatalytic rate of ternary heterojunction photocatalysts. It has been demonstrated that superoxide radicals play a significant role in the photodegradation process. A kinetic analysis revealed that the higher efficiency (97.9%) was associated with a higher rate constant (k = 0.0345 min‒1). A Fe2SiO4/Fe2O3/g-C3N4 nanocomposite is an excellent choice for large-scale applications because of its exceptional stability and recyclability.

Facile preparation and characterization of Zn2Ti3O8/g-C3N4 nanocomposites for degradation of rhodamine B under simulated sunlight

Zinc titanate (Zn2Ti3O8, ZTO) was initially synthesized using a straightforward and inexpensive Pechini approach, and subsequently Zn2Ti3O8/g-C3N4 (ZTO/CN) nanocomposites with varied contents were created using an ultrasonic-assisted co-precipitation process. Based on the appropriate bandgaps (2.0 eV and 2.7 eV), the photodegradation of rhodamine B (RhB) was studied. This is the first time that ZTO/CN nanocomposites are studied for the degradation of organic pollutants. The results showed that the best performance belonged to the sample with a mass ratio of 0.25 to 1 among different ZTO/CN nanocomposites. Therefore, 50 mg of ZTO/CN (0.25:1) degraded 89.0 % of 10 ppm RhB. Scavenger testing revealed that superoxide radicals and holes played significant parts in photodegradation processes.

Enhanced Photocatalytic Activity of π-Conjugated Pyridine Rings-Modified C3N4/Bi@BiOCl Z-Scheme Heterogeneous Material.

The enhanced photocatalytic properties of Z-Scheme Bi@BiOCl/C3N4-DPY heterojunction materials were successfully prepared by the ultrasonic-assisted coprecipitation method. The Bi@BiOCl/C3N4-DPY heterojunction exhibited remarkable photocatalytic activity under visible light irradiation, and the degradation rate of methyl orange (MO) was about 90.6% in 180 min. This impressive efficiency is mainly due to the Z-Scheme charge transfer mechanism in Bi@BiOCl/C3N4-DPY, resulting in the efficient separation of charge carriers and an increase in the REDOX potential of photogenerated electrons and holes. C3N4 was modified with a π-deficient conjugated pyridine ring, which caused the light absorption redshift, promoted the formation of oxidizing •O2-, and improved the photocatalytic activity. At the same time, a well-aligned heterojunction is formed at the interface between C3N4-DPY and BiOCl, facilitating the seamless transfer of light-induced electrons from the LUMO of C3N4-DPY to the CB of BiOCl. In addition, the addition of Bi introduces a unique band gap reduction effect, resulting in a change in the density of the band states, which further promotes charge transfer and separation. It is worth noting that the introduction of metallic bismuth (Bi) brings about a unique band gap reduction effect, resulting in a change in the density of states within the band, which ultimately promotes charge transfer and separation. The Z-scheme charge migration inside Bi@BiOCl/C3N4-DPY further promotes the efficient separation of photogenerated electron-hole pairs, greatly improving the overall efficiency of the material. The Z-structured photocatalyst developed in this study has great application potential in various fields of photocatalysis.

Electrochemical, Photocatalytic and Photoluminescence properties of BaWO4 and rGO-BaWO4 nano-composites: A Comparative study

The rGO-BaWO4 (rGO-BWO) nanocomposites were synthesized by employing the ultrasonic-assisted co-precipitation method. Nanocomposites formed with BWO nanoparticles anchored to layers of reduced graphene oxide through in situ reduction and a homogeneous distribution of BWO nanoparticles were confirmed by SEM images. The rGO-BWO nanocomposite showed improved photocatalytic activity for the visible light degradation of Methylene Blue (MB) dye with a rate constant of 27 × 10−3 min−1 compared to pristine BWO. The band gaps for BWO nanoparticles estimated using UV–Vis DRS are of the order of 3.25 eV–4.25 eV, while they were 2.78 eV–3 eV for rGO−BWO nanocomposites. The delocalized surface charges induced by the interactions between the rGO and BWO nanoparticles in the composite material might be responsible for the observed reduction in the band gap. Photoluminescent investigations demonstrate that rGO-BWO nanocomposites have a lower peak intensity compared to pure BWO particles, indicating a reduced recombination rate and better photocatalytic activity. In particular, when used as supercapacitor electrodes, the produced nanocomposites outperform BWO. Because of its larger surface area, the rGO-BWO nanocomposites display two-fold higher outcomes including 586, 571, 406, 375 and 307 F/g compared to BWO 391, 352, 291, 214 and 174 F/g at each current density 1, 2, 3, 5 and 10 A/g and faster charge transfer owing to improved porosity in the surface of rGO-BWO.

Ultrasonic-assisted Co-precipitation synthesis of CoAl2O4 with different capping agents: Determination of electrical and optical features

In this study, cobalt aluminate nanoparticles were synthesized by a modified coprecipitation method using different capping agents and ultrasonic treatment. Optical, morphological and structural analyses of the samples were performed and the dielectric behaviour of the samples was investigated using the impedance spectroscopy technique in the frequency range of 10–107 Hz and at room temperature. It was determined that with the use of capping agent for NPs with 30–60 nm grain size, the optical forbidden energy gaps increased from 1.80 eV to 2.15 eV and the Co/Al ratio decreased from 0.534 to 0.362. It has been shown by Williamson Hall analysis that lattice shrinkage occurs with the use of the capping agent in the structural analysis of the materials. It has been determined that the type of capping agent is effective on the grain size, optical absorption and structural content of the final product, and especially lattice shrinkage is an effective mechanism in grain size reduction. The effect seen in the materials produced with the highest OA caused a 50 % decrease in grain size compared to the one without the use of capping agent. AC impedance spectroscopy showed that CoAl2O4 spinel structures have the inhomogeneous distribution of conductive grains with limited conductive grain boundaries and behave in accordance with Koops' model. It was determined that the use of dielectric properties in the high-frequency region improved with the use of capping agents.

Zn-doped NiO nanocomposites for efficient solar light-assisted wastewater treatment and its profound for low phytotoxic and antibacterial applications

The present research aims to eradicate methylene blue toxins (test effluent) in aquatic environments using photocatalytic Zn-doped NiO nanoparticles. Ultrasonic-assisted co-precipitation process was adopted to synthesize Zn-doped NiO nanoparticles. The prepared samples were characterized by XRD, SEM, in vitro antibacterial, phytotoxicity, and photocatalytic analysis. XRD patterns exhibited a solitary phase of Fm3m space-group-cubic-structured Zn-doped NiO crystallites with a preferred orientation along the (200) plane. SEM analysis explored the formation of nanorods with hexagonal ends. Zn-doped NiO is capable of rendering significant antibacterial efficacy against Staphylococcus aureus (MTCC 25923) and Escherichia coli (MTCC 25922) bacterial strains. Zn-doped NiO nanocomposites are appropriate for decomposing methylene blue (MB) contaminants in 120 minutes under direct sunlight irradiation. Hydroponically grown Vigna radiata seedlings and Mentha piperita L plants in dye-deprived water show minimal phytotoxicity and enhanced physiological aspects of plants. The outcome of the current research encouraged bringing new ideas for further utilization of textile MB effluent after photocatalytic treatment to non-domestic applications, such as irrigating roadside plants, public parks, and gardens.

Preparation, characterization and application of BaZr0.1Ce0.7Y0.2O3-δ for a high-performance and stable proton ceramic electrochemical cell

The high sintering temperature (＞1500 °C) of the electrolyte is the main challenge for the application of proton ceramic electrochemical cells (PCECs). In this work, we prepare BaZr0.1Ce0.7Y0.2O3-δ (BZCY) electrolyte materials by various synthetic routes, compare their physicochemical properties and optimize their applications in PCEC. The BZCYs powder prepared by the solid state reaction method shows a large grain size of 2–3 μm and is used in the support layer. The optimal proportion of the support is determined according to the thermal expansion characterization. The BZCYp powder from the ultrasonic-assisted co-precipitation method presents well dispersed particles of 30∼50 nm and is used as the electrolyte layer and in the fuel electrode layer. The electrolyte becomes very dense after co-sintering with the support at 1400 °C without any sintering aids, giving a low conducting activation energy of 0.26 eV. The single cell demonstrates excellent performance and good stability. Under steam electrolysis mode, the cell gives 840 and 260 mAcm−2 @1.3V at 600 °C and 500 °C. Under cell mode, the cell displays 0.46 and 0.21Wcm−2@0.7V at 600 °C and 500 °C, respectively.

Magnetically Recoverable CMC/Fe3O4 Nanocomposite for Efficient Removal of Hg(II) and Cd(II) ions from the Aqueous Solution

ABSTRACT Heavy metals such as Mercury and Cadmium are highly cytotoxic metals when released into the environment and pose serious hazards to the ecosystem. The current study introduces CMC/Fe3O4 nanocomposite as an effective, magnetically recyclable, low-cost, and environment-friendly biopolymer-based adsorbent for removing these harmful contaminants from waste water. This nanocomposite was synthesized by ultrasonic assisted coprecipitation method and characterized using X-ray diffractometer, scanning electron microscope, BET surface area, Fourier-transform infrared spectroscopy, etc. Series of batch experiments were carried out at room temperature to determine the adsorption capacity of CMC/Fe3O4, which is found to be 243.52 mg g−1 and 414.04 mg g−1 toward Hg(II) and Cd(II), respectively, at optimum conditions. Optimum parameters for Hg(II) were pH 7, initial concentration 200 mg L−1, and 0.02 g of adsorbent loading, while for Cd(II) experiments were conducted using pH 6, initial concentration 500 mg L−1, and 0.03 g of adsorbent. The adsorption was well described by the Langmuir isotherm model and Pseudo-second order kinetic model, and the thermodynamic study reveals spontaneous and endothermic nature of adsorption.

In-situ synthesis of Bi2WO6/AgBr/Ag4V2O7 with double Z-scheme heterojunction for oxytetracycline degradation and weakening toxicity

Herein, a novel Bi2WO6/AgBr/Ag4V2O7 double Z-scheme heterojunction photocatalytic material was synthesized by the ultrasonic-assisted coprecipitation method. When the content of AgBr in Bi2WO6/AgBr/Ag4V2O7 is 30 wt% and the content of Ag4V2O7 is 1 wt%, under the optimized reaction conditions, the degradation rate of Bi2WO6/AgBr/Ag4V2O7 to oxytetracycline (OTC) reached 88.13 % within 60 min, and the photocatalytic activity decreased only slightly after repeated use for three times, other than that, the toxicity of OTC to wheat decreased significantly after degradation. The morphology, composition, crystal structure and visible light absorption capacity of the samples are investigated by a series of characterization techniques. Furthermore, free radical capture experiment, electron paramagnetic resonance (EPR) experiment and liquid chromatography-mass spectrometry (LC-MS) were used to explore the possible photocatalytic mechanism and degradation path of OTC. The results show that the improvement of photocatalytic activity is attributed to the construction of a double Z-scheme heterojunction, which provides a more effective structural space for the separation of photogenerated e--h+ pairs. This study provides a new idea for the separation of photogenerated e--h+ pairs and broadens the response range of visible light, and proposes a new strategy for the environmental treatment of photocatalysts.

Preparation and characterization of nano- Fe(OH)3, its composites with two natural zeolites, and granulation of them for nitrate removal from polluted water

The development of a cost-efficient, highly effective, and granular shape adsorbent is highly desired for nitrate removal. In this study, two different Fe(OH)3 nanoparticles with amorphous and crystalline structures, and nanocomposites were successfully synthesized using the ultrasonic-assisted co-precipitation. Both nanoparticles were scrutinized using FTIR, SEM, and XRD. Crystallized Fe(OH)3/zeolite nanocomposites were not efficient for nitrate removal;hence, the rest of the study was carried out with amorphous Fe(OH)3 nanoparticles (Am-Fe(OH)3). Clinoptilolite and analcime were acid-washed and used as a support for synthesized Am-Fe(OH)3 nanoparticles. Nanocomposites of clinoptilolite and analcime were abbreviated as Fe(OH)3/Clin and Fe(OH)3/Anc, respectively. The nanocomposites were characterized by BET, FTIR, SEM, EDS, and XRD techniques. Subsequently, granules of the above-mentioned nanocomposites were prepared using the wet gelation method and alginate. Two crucial features of pH and adsorbent:alginate ratio, were assessed and optimized as 11–12 and 1:3, respectively. The performance of granules were investigated regarding pH, time, and adsorbent dosage. Fe(OH)3/Clin and Fe(OH)3/Anc granules removed 96.82% and 34.02% of nitrate from a contaminated solution with initial concertation of 50 mg l−1. Overall, Fe(OH)3/Clin granule was an effective adsorbent for nitrate removal. The maximum adsorption capacity of Fe(OH)3/Anc and Fe(OH)3/Clin were 0.4443 mg g−1 and 5.6211 mg g−1 for 0.2 g of each adsorbent, respectively. Both adsorbents displayed good compatibility with the pseudo-second-order kinetic model.

Textile wastewater depuration using a green cellulose based Fe3O4 bionanocomposite

Supported iron oxide nanoparticles (NPs) on natural fiber surfaces have enormous potential in wastewater depuration strategies. We describe here the fabrication and advanced oxidation capabilities of a bionanocomposite based on cellulosic fique fibers (FF) decorated with magnetite (Fe3O4) NPs. The composite material’s assembly was monitored using FESEM, XPS, ATR-IR, XRD, and TGA. Cellulose in FF undergoes an alkaline treatment, resulting in a heterogeneous and positively charged microstructure with channels and cavities acting as nanoreactors, facilitating size control, dispersion, and stabilization of the Fe3O4 NPs via an ultrasonic-assisted co-precipitation method. The bionanocomposite material (FF/Fe3O4) promotes color removal from indigo carmine (IC) solutions via heterogeneous Fenton-like reactions. UV–vis and MS data show the removal of up to 90% of the color in IC-spiked model aqueous samples through oxidation reactions within 5 min for up to 10 cycles. The bionanocomposite catalytic performance is significantly affected by pH and oxidant (H2O2) concentration. In addition, after treating a real effluent from a denim factory with the FF/Fe3O4 bionanocomposite for 120 min, we observed reductions of 24% in chemical oxygen demand (COD), 100% in surfactant content, 99% in true and apparent color, and 99% in turbidity.

Comparative X-Ray Diffraction (XRD) Study on the Synthesis of Natural Based Magnetic Silica Nanoparticles

The aim of this study was to compare the synthesis process of magnetic silica nanoparticles (Fe-SNP) through the analysis of X-ray Diffraction (XRD) results. Fe3O4 magnetic nanopowders was synthesized by ultrasonic assisted co-precipitation and Fe-SNP was synthesized by direct mixing method of sodium silicate (Na2SiO3) and magnetite (Fe3O4) and the sol-gel method. Silica sludge was used as a silica source from Indonesia geothermal power plant waste. The synthesized of Fe-SNP is the functionalization of Fe3O4 with silica. Variations concentration of Na2SiO3 is used for the direct mixing method and variations of Fe3O4 form is used for the sol-gel method. Particles formed and particle size were characterized by XRD. The XRD results showed that there is no SiO2 phase in the sample synthesized by direct mixing method while two phases of SiO2 and Fe3O4 were found in the sample synthesized by sol-gel method. The size of the Fe3O4 nanoparticles calculated with Scherer’s formula and it obtained 19.9 nm, while the Fe3O4 nanoparticles with the addition of 20 mL and 6 mL Na2SiO3 concentrations were 6,53 nm and 10,23 nm. For the sol-gel method the size of Fe3O4 nanoparticles obtained was 11,03 using Fe3O4 powders and 9,86 using Fe3O4 solutions.

Photocatalytic Degradation of Methylene Blue using Fe2O3-TiO2/Kaolinite under Visible Light Illumination

<p>Combining TiO<sub>2</sub> and a semiconductor with a smaller band gap, such as Fe<sub>2</sub>O<sub>3</sub>, to form a heterojunction composite can increase its photocatalytic activity. In this work, the Fe<sub>2</sub>O<sub>3</sub>-TiO<sub>2</sub>/kaolinite composites were successfully synthesized by ultrasonic-assisted coprecipitation using titanium-tetraisopropoxide (TTIP) dan Fe (NO<sub>3</sub>)<sub>3</sub>.9H<sub>2</sub>O as precursors. Using kaolinite as a matrix also increases the photocatalyst’s surface area. The obtained Fe<sub>2</sub>O<sub>3</sub>-TiO<sub>2</sub>/kaolinite composites were characterized. The crystal phase was characterized using X-Ray Diffraction and resulted in anatase with a crystallite size average of 9,7 nm. Fourier Transform Infrared Spectrophotometer (FTIR) shows the peak at a wavenumber 574-1210 cm<sup>−1</sup> ascribed TiO<sub>2</sub> and Fe<sub>2</sub>O<sub>3</sub> incorporated into kaolinite. The Optical properties show the absorption edge of Fe<sub>2</sub>O<sub>3</sub>-TiO<sub>2</sub>/kaolinite is redshift toward the visible light region. The result showed that the photocatalytic activity of Fe<sub>2</sub>O<sub>3</sub>-TiO<sub>2</sub>/kaolinite composites with heterostructure was more active than the corresponding Fe<sub>2</sub>O<sub>3</sub> or pure TiO<sub>2</sub> in the degradation of methylene blue under visible light illumination, which can degrade 83% for 180 minutes. Fe<sub>2</sub>O<sub>3</sub> and kaolinite cause its synergistic effect as supporting materials. Furthermore, it indicates that the recombination of photo hole and photoelectron charge pair can be minimized. The Fe<sub>2</sub>O<sub>3</sub>-TiO<sub>2</sub>/kaolinite composite is a promising photocatalyst to degrade organic pollutants for wastewater treatment.</p>

Preparation of copper-based catalysts from electroplating sludge by ultrasound treatment and their antibiotic degradation performance

The recovery of heavy metals from electroplating sludge is important for alleviating heavy metal pollution and recycling metal resources. However, the selective recovery of metal resources is limited by the complexity of electroplating sludge. Herein, CuFe bimetallic Fenton-like catalysts were successfully prepared from electroplating sludge by a facile room-temperature ultrasonic-assisted co-precipitation method. The prepared CuFe–S mainly consisted of nanorods with diameters of 20–30 nm and lengths of 100–200 nm and a small number of irregular particles. Subsequently, we performed tetracycline (TC) degradation experiments, and the results showed that the product CuFe–S had very good performance over a wide pH range (2–11). At an initial pH = 2, CuFe–S could degrade 91.9% of 50 mg L−1 TC aqueous solution within 30 min, which is better than that of a single metal catalyst. Free radical scavenging experiments and electron paramagnetic resonance (EPR) tests revealed that ·OH was the main active species for the degradation of TC by CuFe–S. In conclusion, a CuFe bimetallic Fenton-like catalyst was developed for the catalytic degradation of antibiotics, which provides a novel technical route for the resource utilization of electroplating sludge and shows an important practical application prospect.

Ultrasonic-assisted preparation of interlaced layered hydrotalcite (U–Fe/Al-LDH) for high-efficiency removal of Cr(VI): Enhancing adsorption-coupled reduction capacity and stability

Cr(VI) contamination in aquatic systems has been a challenge for environmental science researchers. To environmental-friendly, stable, and efficiently remove Cr (VI), a novel layered double hydroxide was prepared through the ultrasonic-assisted co-precipitation method. The ultrasonic-assisted step prevented the Fe2+ oxidation, improved the morphology and performance, and finally, the adsorption-coupled reduction capacity and stability were enhanced. By adding U–Fe/Al-LDH (1.0 g/L) for Cr(VI) (100 mg/L), the removal rate reached 82.24%. The removal data were well fitted by the pseudo-second-order kinetic and Langmuir isotherm model. Using U–Fe/Al-LDH can be performed over a wide pH range (2–10), with a theoretical maximum removal capacity of 118.65 mg/g. The Cr(VI) with high toxicity was adsorbed and reduced to low-toxicity Cr(III). In the final phase, stable Cr(III) complex precipitates were generated. After 30 days, the dynamic leaching amounts of total Cr in used U–Fe/Al-LDH-2 were 0.1052 mg/L. Combined with the results of the influence experiment of coexisting anions and oxidants and the SO42− release experiment, the stability of the removal effect and the safety of U–Fe/Al-LDH were proved. In conclusion, U–Fe/Al-LDH-2 is a promising remediation agent and a feasible Cr(VI) removal method for the practical remediation.

Synthesis of magnetite nanoparticles coated with polyvinyl alcohol for hyperthermia application

One of the main challenges in hyperthermia treatment is how to improve the heating performance of nanoparticles with high specific loss power (SLP). To tackle this challenge, magnetite nanoparticles (MNPs) and coated magnetite nanoparticles with polyvinyl alcohol (PVA@MNPs) were fabricated via ultrasonic-assisted coprecipitation technique. The obtained nanoparticles were characterized by using FT-IR, TEM, TGA, XRD, ICP-OES, DLS, zeta potential, VSM and UV–Vis spectroscopy. The self-heating properties of the MNPs and PVA@MNPs were studied under alternating magnetic strength, frequency and induction time. MNPs and PVA@MNPs showed that the nanoparticles have a nearly spherical shape ranging between 12.3 ± 3.2 and 10 ± 2.5 nm, respectively. The higher value of zeta potentials of PVA@MNPs (− 11.49 mV) implies that the nanoparticle may show good stability in aqueous solutions. The magnetization saturation values were 41.98 and 45.08 emu g−1 for MNPs and PVA@MNPs, respectively. The prepared nanoparticles showed small coercivity and a remanence magnetization due to the soft magnetic nature of the prepared nanoparticles. The highest SLP value was 163.81 W g−1 for PVA@MNPs, while the lowest SLP value was 4.84 W g−1 for MNPs under the same magnetic field condition. The presence of PVA shell improved the particle stability and the magnetization for PVA@ MNPs. This successfully caused an improvement in the heating performance and magnetic hyperthermia as well. These features make the prepared PVA@MNPs in this study applicable as hyperthermic agents for biomedical applications.

Functionalized iron oxide nanoparticles: synthesis through ultrasonic-assisted co-precipitation and performance as hyperthermic agents for biomedical applications

Dual-functional iron oxide nanoparticles (IONPs), displaying self-heating and antibacterial effects are highly desired for biomedical application. This study involved the synthesis of functionalized IONPs coated with 3-aminopropyltriethoxysilane and polyethylene glycol via ultrasonic-assisted co-precipitation technique. The synthesized IONPs were then characterized by using Fourier-transform infrared spectroscopy, X-ray diffraction, dynamic light scattering, scanning electron microscopy, zeta potential, vibrating sample magnetometer and thermogravimetric analysis techniques. In addition, the effect of the synthesized IONPs on bacterial growth (S. aureus and E. coli) was studied. The influence of magnetic field power, as well as the viscous carriers on the heating efficiency of the synthesized IONPs was investigated. The specific absorption rate values increased as the power increased and decreased with the increase in the carrier viscosity. These characteristics render the synthesized iron oxide nanoparticles synthesized in the present study suitable for biomedical application as hyperthermic agents.