Simple Co-precipitation Method Research Articles

Preparation and characterization of zein-based core-shell nanoparticles for encapsulation and delivery of hydrophobic nutrient molecules: Enhancing environmental stress resistance and antioxidant activity

A simple reverse solvent co-precipitation method was designed to prepare zein/debranched oxidized starch core-shell composite nanoparticles. Studies have shown that the composite nanoparticles have good stability and the ability to protect resveratrol from chemical degradation during long-term storage, pasteurization, and ultraviolet irradiation. The encapsulation rate of resveratrol in composite nanoparticles (81.15%) was significantly higher than that of pure protein nanoparticles (47.15%). The results of FT-IR (fourier transform infrared spectroscopy), circular dichroism, and fluorescence spectra show that hydrogen bonding, hydrophobic interaction, and electrostatic interaction exist in the composite nanoparticles. Under pasteurization conditions, ultraviolet radiation, and two weeks of room-temperature storage, the composite nanoparticles can better maintain the biological activity of nutrient molecules. Moreover, the particles can maintain stability in different pH and ionic strength environments and gradually degrade and release active molecules in the intestinal tract in vitro in the simulated gastrointestinal environment. These results show that zein/debranched oxidized starch nanoparticles (ZDNPs) have great potential for application in the fields of functional drinks, food, and biomedicine-related delivery.

Effect of unpaired electron number elements (Al, Cr, Mn) doping in Fe2O3 on ortho to para hydrogen conversion at 77 K

Para hydrogen (p-H2), as a low-energy spin isomer of hydrogen molecule, has an important significance in the storage and transportation of liquid hydrogen. The ortho hydrogen (o-H2) to p-H2 conversion catalyst accelerates the intrinsically slow o-H2 to p-H2 conversion and becomes an essential component of the hydrogen liquefaction process. In this paper, doped Fe2O3 with different hetero elements (X-FO, X = Al, Cr, Mn) are prepared by a simple co-precipitation method to explore the effect of different unpaired electron numbers in doping elements on catalytic performance. It is shown that the disorder in the internal crystal structure of X-FO caused by doping of hetero elements is the main reason for the increased performance of X-FO, as this leads directly to an increase in the internal magnetic disorder. The catalytic performance is enhanced with the increase in the number of unpaired electrons in doping elements. Mn-FO with high unpaired electron number exhibits optimal catalytic performance. When the hydrogen flow rate is 100 mL min−1, p-H2 content is 49.45 % after catalytic conversion at 77 K. In this paper, a simple method is adopted, which has advantages in terms of production process and cost, and provides experimental support for the large-scale production of catalysts.

One Pot Synthesis of Nanofiber-Coated Magnetic Composites as Magnetic Dispersive Solid-Phase Extraction Adsorbents for Rapid Determination of Tetracyclines in Aquatic Food Products.

A magnetic adsorbent based on a C-nanofiber (Fe3O4@C-NFs) nanocomposite was synthesized using a simple one-pot co-precipitation method. The characterized results showed that the obtained C-nanofiber-coated magnetic nanoparticles had many attractive features such as a large specific surface area and a highly interwoven and branched mesoporous structure, as well as distinguished magnetism. The nanocomposite was then used as an adsorbent in the magnetic solid phase extraction (MSPE) of four typical tetracyclines (oxytetracycline, tetracycline, chlortetracycline, and doxycycline) in aquatic products. The TCs in the extract were determined using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Experimental variables of MSPE, including the sorbent amount, pH condition, adsorption and desorption time, and desorption solvent, were investigated and optimized systematically. The method validation indicated that the developed method showed good linearity (R2 > 0.995) in the range of 1.0-200 ng/mL. The average recoveries at the spiked levels ranged from 90.7% to 102.7% with intra-day and inter-day relative standard deviations (RSDs, n = 6) ranging from 3.72% to 8.17% and 4.20% to 9.69%, respectively. The limit of detection (LOD) and limit of quantification (LOQ) for the four kinds of TCs were 0.7 μg/kg and 2.0 μg/kg, respectively. Finally, MSPE based on C-nanofiber-coated magnetic nanoparticles was successfully applied to TC analysis in real aquatic products (grass carp, large yellow croaker, snakehead, mandarin fish, Penaeus vannamei, swimming crab, etc.). Compared with traditional extraction methods, the proposed method for TC analysis in aquatic products is more sensitive, effective, recyclable, and environmentally friendly.

Determination of Sb(V) in water samples via solid-phase extraction based on Mg–Al layered double hydroxide sorbents prior to ICP-MS

Solid-phase extraction (SPE) is an effective method for detecting trace metals. Mg-Al-layered double hydroxide (Mg-Al LDH) materials as an effective adsorbent for SPE because of its large anion exchange capacity, high yield and low cost. A new method was developed for detecting Sb(V) with SPE coupled with inductively coupled plasma mass spectrometry. Mg-Al LDH was synthesized via a simple coprecipitation method and characterized using scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffractometry, and X-ray photoelectron spectroscopy. Factors affecting the Sb(V) extraction efficiency, such as the eluent type and volume, solution pH, loading flow rate, sample volume, adsorbent weight, and salt concentration, were optimized. Under optimal conditions, the SPE method exhibited good linearity (R2 ≥ 0.999) in the range of 0.1–100 µg L−1 with a limit of detection equal to 0.017 µg L−1, good repeatability and reproducibility, and intraday and interday relative standard deviations of 1.84% and 1.48%, respectively. Furthermore, the method was applied to determine traces of antimony in drinking water and bottled water, and findings revealed recoveries between 82.7%–92.1%.

Nexus Advances Using Marine Biopolymeric Gel Material as a Photocatalyst for the Oxidation of Agricultural Wastewater Containing Insecticides.

The attention of the research community is focused not only on waste elimination, but also on waste valorization. The natural marine biopolymer gel substance chitosan, which can be derived from the waste substances of marine life, is a polymer-matrix-based nanocomposite. Chitosan attracts special attention due to its potential applications, especially in wastewater treatment. In this regard, magnetite-incorporated chitosan powders of nanometer scale were synthesized by a simple co-precipitation method to attain the dual functions of chitosan gel and magnetite. The synthesized magnetite-incorporated chitosan nanopowders were verified using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, a vibrating-sample magnetometer (VSM), a scanning electron microscope (SEM), and transmission electron microscopy (TEM) images, which showed that the synthesized magnetite-incorporated chitosan was nanosized. The superior application of such a material to offset the deterioration of the environment caused by insecticides is attained through a photocatalytic reaction. The experimental results verified the function of magnetite-incorporated chitosan, since it increased the composite-specific surface area, resulting in high methomyl molecule oxidation. Methomyl oxidation reached almost complete insecticide removal (99%) within only one hour of irradiance time. The optimal operational conditions were investigated, and the maximal removal rate occurred when the aqueous solution was at an acidic pH of 3.0. The reaction was affected by differing hydrogen peroxide and catalyst doses, and the optimized reagent was recorded at the levels of 40 and 400 mg/L of catalyst and hydrogen peroxide, respectively. Also, catalyst reusability was attained, confirming its sustainability, since it could be used for successive cycles. From the current investigation, it is proposed that magnetite-chitosan nanoparticles could serve as a promising photocatalyst for the elimination of insecticides from wastewater in a green manner.

PW6Mo6/ZIF-67@NF composite with exposed Co nodes as efficient oxygen evolution reaction electrocatalyst

The construction of efficient, sustainable, and low-cost nonprecious metal electrocatalysts for oxygen evolution reaction (OER) is necessary for the realization of electrocatalytic overall water splitting. Herein, the PW6Mo6/ZIF-67@NF is prepared using a simple coprecipitation method. Characterization results indicate that the PW6Mo6 induces the exposure of Co nodes in ZIF-67, which can act as catalytic active sites for OER. Meanwhile, the introduction of PW6Mo6 improves the conductivity and electrochemical active surface area of ZIF-67, which further enhances the OER performance. The electrochemical test results show that the PW6Mo6/ZIF-67@NF exhibit an ultralow overpotential of 201 mV at 10 mA cm−2 and a small Tafel slope of 55 mV dec−1 for OER, which is lower than that of ZIF-67@NF (329 mV, 286 mV dec−1). Our study demonstrates the potential of polyoxometalate and ZIF composites to decrease the barriers of OER and provides a feasible approach for exploring economical and practical electrocatalysts.

Photocatalytic degradation efficiency of Rhodamine-B for CuO/CdO nanosheets attained through simple co-precipitation method

In the present investigation, the growth of CuO/CdO nanosheets by simple coprecipitation method and characterized by XRD, SEM with EDX, TEM, UV–visible and PL. The incorporation of the non-ionic surfactant Triton X-100 blend with CuO/CdO resulted in hexagonal shaped grains with a nanoporous structure. The pristine CuO and CdO display monoclinic and cubic phases, respectively, whereas the CuO/CdO exhibits a combination of two phases, as proven by XRD analysis. According to TEM analysis the CuO/CdO composite particle size was reduced in the range between 20 and 50 nm resulting, the bandgap value is decreased around 1.26 eV due to size effect. The photocatalytic activity against Rhodamine-B (RhB) showed a 94 % degradation efficiency as compared to pristine CuO (71.42 %) and CdO (77.83 %). Furthermore, the CuO/CdO nanocomposite catalyst dosage increasing the degradation efficiency was found to be 97.62 %. Although the nitration process is more efficient at pH 6, the degradation efficiency for CuO, CdO, and CuO/CdO was found to be 75.74, 85.96 %, and 99.88 % at pH 6. In acidic solution, the reusability of CuO/CdO was outstanding with a 95.80 % degradation efficiency after five successive cycles.

Synthesis of Inexpensive Ternary Metal Oxides by a Co-Precipitation Method for Catalytic Oxidation of Carbon Monoxide.

By using a simple co-precipitation method, new Fe2 O3 -based nanocatalysts (samples) were synthesized. The samples were composites of two or three transition metal oxides, MOx (M=Fe, Mn, Co, Ni, and Cu). The average size of CuO crystallites in the composites composed of two oxide components (CuO-Fe2 O3 ) was about 14.3 nm, while in those composed of three (CuO-MnOx -Fe2 O3 ), the composite's phase compositions were almost in the amorphous form when annealing the sample at 300 °C. The latter sample had a specific surface area higher than that of the former, 207.9 and 142.1 g/m2 , respectively, explaining its higher catalytic CO oxidation. The CO conversion over the CuO-MnOx -Fe2 O3 -300 catalyst (1 g of catalyst, 2600 ppm of CO concentration in air, and 1.0 L/min of gas flow rate) begins at about 40 °C; the temperature for 50 % CO conversion (t50 ) is near 82 °C; and CO removal is almost complete at t99 ≈110 °C. The activity of the optimal sample was tested in different catalytic conditions, thereby observing a high durability of 99-100 % CO conversion at 130 °C. The obtained results were derived from XRD, FTIR, BET, SEM, elemental analysis and mapping, as well as catalytic experiments.

Wet-chemical synthesis of sponge-like porous Zn-doped copper oxide ceramic as an efficient solar-light triggered photocatalyst for multiple applications

Abstract This work presents a simple co-precipitation method for making Zn-doped copper oxide (C1−x (Zn) x O) that is nanostructured, porous, active in visible light, and highly conductive. The combined impacts of doping, structural modifications, and nanoscaled synthesis contribute to the development of a novel catalyst that has inherent characteristics. Physicochemical studies confirm the coexistence of all desired features in the C1−x (Zn) x O photocatalyst. The formed photocatalyst’s dye-destroying and antimicrobial properties were carefully examined and compared to those of pristine copper oxide (PCO) that had not been doped. When tested against Escherichia coli (a “negative strain”) and Staphylococcus aureus (a “positive strain”), the antimicrobial properties of the C1−x (Zn) x O photocatalyst were better than those of PCO and on par with those of commercially available drugs. Also, C1−x (Zn) x O photocatalyst gets rid of reactive orange 4 (RO-4) dye more effectively and faster (0.023 min−1) than PCO photocatalyst (0.11 min−1) by using simple sorption and photocatalytic annihilation. The C1−x (Zn) x O photocatalyst eliminated 90.25 % of RO-4 dye under visible light irradiation. Under identical circumstances, the PCO photocatalyst removed 65.12 % of the RO-4 dye. The boosted bactericidal and photocatalytic activity of the C1−x (Zn) x O photocatalyst may be attributed to its larger surface area (56.5 m2 g−1), good electrical conductivity (2.33 × 10−3 S m−1), low bandgap (1.98 eV), and doping-induced structural defects. The developed features increase the light-capturing sites on the catalyst surface, improve the charge transport kinetics, enable the catalysts to harvest visible light, and limit the charge recombination process, allowing our photocatalyst to show exceptional bactericidal and dye annihilation activities. This study opens new avenues for developing metal-substituted metal oxides with porous nanostructures for environmental and ecological protection.

Evaluation of Fe3O4 incorporated functionalized carbon nanotube self-standing buckypaper as electrodes for solid-state symmetric supercapacitor

Iron (II, III) oxide and carbonaceous materials drawn considerable attention in energy storage owing to their special features. In this study, simple reverse co-precipitation, acid functionalization and vacuum filtration methods adopted to synthesis Fe3O4 nanoparticles of size 11 nm and –COOH acid functionalized multi-wall carbon nanotubes (FMWCNT). And further used them to prepare and optimize Fe3O4 in FMWCNT as 15 wt% and 25 wt% self-standing buckypapers of around 30-μm thickness as electrodes for solid-state symmetric capacitor in the form of coin cell. The results show that 15 wt% and 25 wt% of Fe3O4-FMWCNT buckypapers hybrid nanostructures have Fe3O4 nanoparticles successfully incorporated in FMWCNT. The 25 wt% Fe3O4-FMWCNT electrodes with charge transfer resistance of 140 Ohm showed high areal specific capacitance (Cs) 78.5 mF/cm2 and retained 80 % of its Cs until 800 cycles even at high current density of 1 mA/cm2, scan rate of 100 mV/s whereas 15 wt% Fe3O4-FMWCNT showed low Cs of 47 mF/cm2 and retained 80 % of its Cs over 5000 cycles whereas only FMWCNT show Cs is 36 mF/cm2 with 54 Ohm. Finally, a solid-state symmetric supercapacitor coin cell with self-standing 25 wt% Fe3O4-FMWCNT buckypaper showed an excellent power density of 129.5 mW cm−3 and energy density of 3.6 mWh cm−3 is the innovation of the current work. This is mainly attributed to the combined effect of pseudocapacitive behavior from Fe3O4 by faradaic reaction with additional charge transfer resistance and electric double layer (EDLC) behavior from FMWCNTs by non-faradaic of electronic, ionic transport during charging-discharging. As-made solid-state symmetric supercapacitor appears as a high-performance storage device without extra support of current collectors for practical applications and for fabrication of planar capacitors.

Impact of bimetal doping on the structural and optical characteristics of copper oxide nanoparticles to enhance photocatalytic degradation of dyes: an investigative study

Metal oxide nanoparticles have attracted a lot of attention for dye degradation applications as they have better light absorption properties required for the photocatalysis. This paper presents the impact of bi-metal doping (i.e. Cerium and Tungsten) on the structural and optical properties of Copper oxide nanoparticles. Bi-metal doping has shown remarkable impact on the optical properties (i.e. enhanced light absorption) of CuO nanoparticles making it suitable for photocatalytic applications. A simple co-precipitation method was used to synthesize the pure, single-metal doped and bi-metal doped (i.e. Ce, W and Ce-W) CuO nanoparticles. XRD analysis was done to study the structural properties along with crystallite size estimation using Debye-Scherer formula. Absorption band at 852 cm−1 and 650 cm−1 in the FT-IR spectra further confirmed the presence of CeO2 & WO2 in the monoclinic phase of CuO nanoparticles. Maximum absorption wavelength and bandgap are measured using UV–vis Spectroscopy, and it has been observed that both these quantities depend upon the choice of dopant and can be tailored just by choosing the appropriate dopant. The paper presents an extensive analysis using experimental study to compare the impact of Ce, W and bimetal (Ce-W) doping on the structural, optical and photocatalytic properties of CuO nanoparticles. Enhanced optical absorption in the complete visible range is observed in case of bi-metal doped CuO nanoparticles making it a promising candidate for photocatalytic dye degradation application.

Creation of a Highly Active Small Cu-Based Catalyst Derived from Copper Aluminium Layered Double Hydroxide Supported on α-Al2 O3 for Acceptorless Alcohol Dehydrogenation.

A highly dispersed carbonate-intercalated Cu2+ -Al3+ layered double hydroxide (CuAl LDH) was created on an unreactive α-Al2 O3 surface (CuAl LDH@α-Al2 O3 ) via a simple coprecipitation method of Cu2+ and Al3+ under alkaline conditions in the presence of α-Al2 O3 . A highly reducible CuO nanoparticles was generated, accompanied by the formation of CuAl2 O4 on the surface of α-Al2 O3 (CuAlO@α-Al2 O3 ) after calcination at 1073 K in air, as confirmed by powder X-ray diffraction (XRD) and Cu K-edge X-ray absorption near edge structure (XANES). The structural changes during the progressive heating process were monitored by using in-situ temperature-programmed synchrotron XRD (tp-SXRD). The layered structure of CuAl LDH@α-Al2 O3 completely disappeared at 473 K, and CuO or CuAl2 O4 phases began to appear at 823 K or 1023 K, respectively. Our synthesised CuAlO@α-Al2 O3 catalyst was highly active for the acceptorless dehydrogenation of benzylic, aliphatic, or cyclic aliphatic alcohols; the TON based on the amount of Cu increased to 163 from 3.3 of unsupported CuAlO catalyst in 1-phenylethanol dehydrogenation. The results suggested that Cu0 was obtained from the reduction of CuO in the catalyst matrix during the reaction without separate reduction procedure and acted as a catalytically active species.

Simple and fast synthesis of BiOBr/[Bi6O5(OH)3](NO3)5·3H2O composites for efficient photocatalytic degradation of RhB under visible light

In this study, a heterostructure photocatalyst consisting of Bi6O5(OH)3](NO3)5·3H2O (was denoted as BiOOHN) and BiOBr was fabricated via a simple and economic co-precipitation method. In this method, the amount of Br in the composition was controlled by changing the volume of hydrobromic acid (HBr) during the manufacturing process. The photocatalytic performance of the prepared samples by photodegradation of rhodamine B (RhB) solution under visible light radiation was investigated and the optimum amount of HBr was obtained. The results showed that BiOBr/BiOOHN composite has higher photocatalytic efficiency compared to pure BiOOHN and BiOBr, so that almost 100 % of RhB solution was degraded in the presence of BiOBr/BiOOHN composite photocatalyst during 100 min, while this value was equal to 0 % and 21 % for pure BiOOHN and BiOBr, respectively. Results indicated that the BiOOHN band gap is in the ultraviolet region (3.45 eV) and not possible to activate this sample to generate electron-hole pairs under visible radiation. While the energy gap of the samples synthesized in the presence of HBr was around 2.90 eV, which enables the activation of these compounds under visible radiation to generate electron-hole pairs for photocatalytic reactions. Therefore, the weak BiOOHN photocatalytic performance is attributed to the its wide band gap energy in comparison with other samples. Also, the better performance of composite samples compared to pure BiOBr is owing to the formation of a heterostructure between BiOOHN and BiOBr. It leads to better separation of electron-hole pairs at the interface of two semiconductors and hinders their recombination, which improves photocatalytic performance. Also, a mechanism for the photocatalytic reactions of RhB degradation was proposed based on experimental data and the experiment of trapping active species. According to this mechanism, the holes and free hydroxyl radicals (•OH) play a key role in the photocatalytic degradation reactions of RhB.

Effect of in doping on the formaldehyde sensing performance of ZnSnO3 cubes ceramics

In this paper, Zn1-xInxSnO3 cubes were synthesized by a simple co-precipitation method, and the morphology and structure of the samples were characterized by various techniques. The results show that Zn1-xInxSnO3 has a regular cube structure with a size range of 900–1000 nm. It is obtained by N2 absorption and BET calculation that doping In element improves the specific surface area of the material, promotes the reaction between the measured gas and the gas-sensing material, and thus improves the gas-sensing property of the material. The gas-sensing test results indicate that contrasted with the pure ZnSnO3 sample, the optimal operating temperature of the Zn1-xInxSnO3 (ZISO) sample is reduced (200 °C), and the response value is improved. Especially, Zn0·95In0·05SnO3 (ZISO-5) showed a significantly improved response to 100 ppm formaldehyde gas at the optimum operating temperature of 200 °C, which provided rapid, real-time and efficient technical support for formaldehyde detection. In addition, we also discuss the gas-sensing mechanism of the Zn1-xInxSnO3 cube obtained by In doping to formaldehyde. This study provides technical support and theoretical basis for the optimization of gas-sensing property of ZnSnO3 gas-sensing materials.

ZnO-Bi2O3 Heterostructured Composite for the Photocatalytic Degradation of Orange 16 Reactive Dye: Synergistic Effect of UV Irradiation and Hydrogen Peroxide

The development of semiconductor photocatalysts has recently witnessed notable momentum in the photocatalytic degradation of organic pollutants. ZnO is one of the most widely used photocatalysts; however, its activity is limited by the inefficient absorption of visible light and the fast electron–hole recombination. The incorporation of another metal or semiconductor with ZnO boosts its performance. In this present study, a heterostructured ZnO-Bi2O3 composite was synthesized via a simple co-precipitation method and was investigated for the UV-driven photocatalytic degradation of the Reactive Orange 16 (RO16), a model textile dye. The successful fabrication of ZnO-Bi2O3 microstructures with crystalline nature was characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX). The discoloration of the dye solution was quantified using UV–Vis spectroscopy to determine the photocatalytic efficiency. The photocatalytic activity results demonstrated that the photodegradation at ZnO-Bi2O3 heterojunction was more efficient and 300 and 33% faster than individual Bi2O3 and ZnO catalysts, respectively, an effect that is indicative of a synergistic effect. In the presence of ZnO-Bi2O3 particles, the UV light-driven activity for RO16 degradation was twice as high as in its absence. The influence of adding the oxidant H2O2 on the UV-induced photocatalytic degradation was investigated and the results revealed a two-time increase in the photocatalytic activity of ZnO-Bi2O3 compared to UV irradiation alone, which could be ascribed to a summative degradative effect between UV and H2O2. Hence, this approach holds the potential for environmentally friendly wastewater treatment.

Rational design of microflower-like manganese-doped ultrathin cobalt hydroxide nanosheets as bifunctional electrode materials for electrochemical sensing and supercapacitor applications

Noble metal-based electrocatalyst must be replaced for electrochemical applications by earth-rich, highly active, low-cost, and highly efficient dual-function electrocatalysts. In this study, transition metal-based hydroxides (TMHs), such as 2D manganese-doped cobalt hydroxide (Mn-Co(OH)2) ultrafine nanosheets, are investigated using a very simple large-scale co-precipitation method for efficient electrochemical sensing (nitrofurantoin (NFT)) and supercapacitor (SC) applications. The characterization results show that the porous and large surface area, polycrystalline nature, confinement of the 2D orientation, and strong synergistic effect contribute to the admirable electrochemical concert of Mn-Co(OH)2 for both sensing and SC applications. CV, GCD, EIS, and DPV techniques are used to thoroughly investigate electrochemical and physicochemical properties. As an electrochemical sensor, the Mn-Co(OH)2 modified disposable screen-printed carbon electrode (Mn-Co(OH)2/SPCE) shows excellent electrochemical assets for NFT detection with broad linear ranges (0.05–219 μM and 262–641 μM), low detection limit (0.012 μM) and good anti-interference ability. The obtained specific capacitance of Mn-Co(OH)2 is 348.8 F g−1 at 1 A g−1 with a maintenance capacitance of 80.76 % after 5000 cycles at 10 A g−1. The enhanced electrochemical behavior of Mn-Co(OH)2 may be related to the fast diffusion pathways of Mn doping and the enhanced redox reaction (cobalt ions) of the flower-like ultrathin nanosheets owing to their high surface area (214 m2/g). The characterization results and electrochemical performance (sensing and SCs) provide important and noteworthy insights into the synthesis of noble metal-free and high-efficiency transparent 2D TMHs nanosheets with high performance that can be widely used in various applications.

Photocatalytic degradation and removal of type II pyrethroid pesticide (lambda-cyhalothrin) residue from wastewater using nanoceria for agricultural runoff application

Synthetic chemical pesticides' nature, mode of action, and persistence have brought about debates regarding whether the end justifies the means. Lambda-cyhalothrin is an important insecticide for farmers and households, with great accessibility and excellent action against pests and disease-carrying insects. Like other pyrethroid pesticides, Lambda-cyhalothrin targets the nervous system of insects or pests. However, its fate in the environment, especially in water and living systems, has made it crucial to explore methods of treating or degrading its residues in the environment. The present study aimed to develop a suitable method for the photocatalytic degradation and removal of Lambda-cyhalothrin (LCY) from wastewater and agricultural runoff. The nanoceria were used under natural solar irradiation without applying any scavenger chemical or buffer. This was synthesized using a simple co-precipitation method using cerium nitrate hexahydrate as a precursor. The synthesized nanoceria were characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Fourier Transform Infrared spectroscopy (FTIR) and particle size analysis. The average size of the particle was 27 nm. The photocatalytic degradation was conducted in batches with various pesticide concentrations exposed to different amounts of nanoceria. The initial and final concentrations of the LCY at each level were determined using Shimadzu UV spectroscopy. At optimum conditions, nanoceria was found to degrade and remove more than 63% of the initial pesticide concentration. This method can be suitable for degrading and removing pesticide residue from agricultural runoff (at source) and industrial effluents from synthetic pesticide industries.

Simple synthesis of mesoporous ferrite materials as magnetic adsorbents for phosphate removal

AbstractMesoporous MFe2O4 materials (M = Mn, Cu, and Co) as magnetic adsorbents for phosphate removal were synthesized by a simple coprecipitation method without annealing at high temperatures. Several techniques, including powder X‐ray diffraction, field emission electron scanning microscopy, nitrogen adsorption‐desorption and vibrating sample magnetometry were used to characterize the samples. The effects of M2+ ions on their point of zero charge and their phosphate adsorption capacity were investigated. All three samples consist of nanosized particles with cubic spinel structure and ferromagnetic properties, which allows them to be easily separated from aqueous effluents using a magnet. According to the batch experiments, the adsorption isotherms and the adsorption kinetics for these mesoporous materials are well fitted with the nonlinear Langmuir model and the nonlinear pseudo‐second‐order model, respectively. Among them, CuFe2O4 powder showed the best phosphate adsorption performance with the maximum P adsorption capacity of 27.49 mgP g‐1, which can be assigned to the highest surface area and the high pH value at its point of zero charge.

Congregating Ag into γ-Bi2O3 coupled with CoFe2O4 for enhanced visible light photocatalytic degradation of ciprofloxacin, Cr(VI) reduction and genotoxicity studies

The work attempts to construct a highly effective γ-Bi2O3/CoFe2O4/Ag visible active photocatalyst for the enhanced degradation of ciprofloxacin (CIP) and Cr(VI) reduction. γ-Bi2O3/CoFe2O4/Ag photocatalyst was prepared by simple solid phase and co-precipitation methods. The nanosphere shaped CoFe2O4 photocatalyst are embedded on top of γ-Bi2O3 nanotriangle. The addition of Ag into γ-Bi2O3/CoFe2O4 heterojunction primitively facilitates the photocatalytic activity in higher rate. The quantitative analysis of photocatalyst possesses to have lower e−/h+ recombination rate compared to its counterparts. The prepared γ-Bi2O3/CoFe2O4/Ag photocatalyst showed 96.6% degradation of CIP in 220 min and 99.2% reduction of Cr(VI) in 120 min. Additionally, γ-Bi2O3/CoFe2O4/Ag showed outstanding recyclability and long-term stability with a degradation efficiency of 96.5% even after six cycles. The intermediate products formed were identified and the degradation pathway was elucidated by gas chromatography-mass spectrometry analysis. Total organic carbon measurement was carried over to assess the efficiency of complete degradation and the removal percentage was found to be 98%. The end product toxicity study towards bacteria was proven to have less toxicity level when compared to parent compound. Lastly, the genotoxicity of γ-Bi2O3/CoFe2O4/Ag photocatalyst was tested in Allium cepa and the results confirmed to have no cause of toxicity impacts. Overall, the work not only tends to provide a highly visible active γ-Bi2O3/CoFe2O4/Ag photocatalyst, but also attributes to have no further negative imprints in the environment.

Adsorption of phosphate in water by defective UiO-66/Ce2(CO3)3 composite: Adsorption characteristics and mechanisms

In this study, the defect-rich UiO-66 is first synthesized by a two-step strategy, and then a new T-UiO-66/Ce2(CO3)3 (TUC) adsorbent has been successfully synthesized for phosphate removal from water using a simple co-precipitation method. The pseudo-secondary kinetic model and the Langmuir model, respectively, fit the adsorption kinetics and isotherms. The combined thermodynamic analysis shows the spontaneous and heat-absorbing nature of the adsorption process. TUC has a maximum adsorption capacity of 138.9 mg/g at 298 K, and its adsorption capacity is stable throughout a large pH range (4–9). Electrostatic attraction, defect-induced ligand compensation groups and CO32-active groups with phosphate in ligand exchange make up the majority of the adsorption mechanism. Meanwhile, TUC shows excellent adsorption performance for low concentration phosphorus-containing solution. By applying adsorption for 120 min while treating actual water samples, the phosphate concentration can be reduced from 1.68 mg/L to 0.2 mg/L, which is much less than the primary A phosphorus discharge standard of urban wastewater treatment plants. Moreover, the adsorbent shows good stability after five cycles, and the phosphate may still be adsorbed with an efficiency of up to 81% and desorbed with an efficiency of over 85%.