Anchoring of Ag6Si2O7 nanoparticles on α-Fe2O3 short nanotubes as a Z-scheme photocatalyst for improving their photocatalytic performances

Visible-light-assisted peroxydisulfate activation over Ag6Si2O7/Cu(II)-modified palygorskite composite for the effective degradation of organic pollutants by radical and nonradical pathways

Photoassisted persulfate activation (PPA) is highly efficient oxidation process, but the eligible catalysts are scarce. Herein, a visible-light-responsive Ag₆Si₂O₇ was anchored on Cu(II)-exchanged attapulgite (Cu-Pal) via a facile precipitation-deposition method to construct a novel PDS activator. The synthesized catalyst was systemically analyzed by a series of characterization techniques. The results revealed that Ag₆Si₂O₇ nanoparticles were evenly dispersed on Cu-Pal to form heterojunction. 16%-Ag₆Si₂O₇/Cu-Pal, an optimal catalyst exhibited excellent catalytic performance and stability in the visible-light-assisted PDS activation for AR18 degradation. The influences of reaction parameters on this process were investigated. Under the optimal conditions ([catalyst] = 1.0 g L^-1, [PDS] = 3.9 mM, pH_i = 5.1), 50 mg L^-1 of AR18 was completely degraded within 30 min. More importantly, quenching experiments and EPR tests revealed that besides the common SO₄^•- and •OH, ¹O₂ and O₂^•- were generated as main reactive oxygen species in the PPA by 16%-Ag₆Si₂O₇/Cu-Pal. Moreover, it was found that surface hydroxyl groups of the catalyst and copper species incorporated in Pal could significantly influence PDS activation and ROS generation. Based on these results, together with PDS decomposition, fluorescent probe analysis, and XPS analysis of the used catalyst, the possible mechanisms of the PPA by 16%-Ag₆Si₂O₇/Cu-Pal were proposed. Finally, the versatility and practicability of the established PPA process were verified by degrading other organic contaminants and testing effects of the coexisting anions and water matrices on AR18 degradation. This study may provide new insights for designing and developing the efficient heterogeneous catalysis for wastewater treatment via persulfate-based AOP.

Dark–induced vertical growth of chemobrionic architectures in silver based precipitating chemical gardens

Light sensitivity of many silver compounds has restricted observation of silver based chemical gardens. Here we report for the first time, silver based chemical gardens grown in dark. An identical...

Incorporation of a Z-scheme AgI/Ag6Si2O7 heterojunction to PET fabric for efficient and repeatable photocatalytic dye degradation

Anchoring the Z-scheme AgI/Ag6Si2O7 photocatalyst on PET fabric facilitates reuse. AgI enhances the separation effect of photogenerated carriers. The photocatalytic activity and stability of AgI/Ag6Si2O7/PET composites are greatly improved.

Design and synthesis of a novel nanocomposite based on magnetic dopamine nanoparticles for purification of α-amylase from the bovine milk

In this paper, a novel nanocomposite based on magnetic nanoparticles decorated by dopamine were reported. Three modified magnetic nanocomposites by dopamine were offered with different type of linkers. The mentioned magnetic nanocomposites were applied to separate α-amylase protein from fresh bovine milk. All of the magnetic nanocomposites were characterized and investigated by using Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, field-emission scanning microscope, X-ray diffraction pattern, and vibrating-sample magnetometer analyses. To investigate the purifying application, sodium dodecyl sulfate polyacrylamide gel electrophoresis, one-dimensional isoelectric focusing gel electrophoresis, and alpha-amylase activity assay were employed. With paying attention to factors such as yield of purification and concentration of separated protein by each of magnetic nanocomposite, it could be concluded that the length of linkers played an important role in α-amylase protein separation. According to the results, the best separation and purification of α-amylase protein with 49.83% recovery and 40.11-fold purification efficiency was related to longest length linker, 1,4-butanediol diglycidyl ether, because of considerable conjugation with nanocomposite. Also, docking calculation has shown that the binding energy is - 1.697 kcal/mol and ΔG = - 6.844 kcal/mol which result that the interaction process between dopamine and α-amylase protein is spontaneous.

A novel 3D Z-scheme heterojunction photocatalyst: Ag6Si2O7 anchored on flower-like Bi2WO6 and its excellent photocatalytic performance for the degradation of toxic pharmaceutical antibiotics

A novel 3D Ag₆Si₂O₇/Bi₂WO₆ Z-scheme heterojunction exhibited excellent photocatalytic performance for the degradation of toxic pharmaceutical antibiotics.

Fabrication of Ag/AgBr/Ag3VO4 composites with high visible light photocatalytic performance

Herein, Ag/AgBr/Ag₃VO₄ composites were synthesized by a simple continuous precipitation method. The obtained composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy and photoluminescence spectroscopy (PL). Photocatalytic performance of the composites was assessed by the degradation of methyl orange (MO) and tetracycline hydrochloride (TC) under visible light, and the effects of different nominal mass ratios of AgBr and Ag₃VO₄ on the photocatalytic activity were investigated. The results showed that after 20 min of visible light irradiation (λ > 420 nm), the removal rate of MO in the presence of a 5 : 1 sample reached 98.6%. The EIS and photocurrent results demonstrated that the enhancement of the visible light photocatalytic activity was attributed to the efficient electron–hole pair separation. In addition, the scavenging reactions conducted via the addition of different scavengers confirmed that h⁺ and ·O²⁻ were the main active species in the reaction. The present study offers potential for the degradation of contaminants.

Ag/AgBr/Ag₃VO₄ composites were synthesized by a simple continuous precipitation method, which were used to degrade organic pollutants and found to have excellent photocatalytic properties.

SiO₂ Stabilized Magnetic Nanoparticles as a Highly Effective Catalyst for the Degradation of Basic Fuchsin in Industrial Dye Wastewaters

Catalytic degradation of organic pollutants by nanomaterials is an effective way for environmental remediation. The Fenton reaction involving H₂O₂ oxidation catalysed by Fe³⁺ is an advisable way for wastewater degradation. Herein, Fe₃O₄/SiO₂ core-shell nanoparticles were prepared as catalyst by coprecipitation and sol-gel methods, and this catalyst is used for degradation of fuchsin in wastewater by H₂O₂. The Fenton reaction between H₂O₂ and Fe₃O₄ is proposed to explain the catalytic performance. The coating of SiO₂ on Fe₃O₄ nanoparticles could dramatically stabilize the Fe₃O₄ in aqueous solution and prevent their oxidation. More importantly, the magnetic property of Fe₃O₄ nanoparticles endows them with good recyclability. Thus, due to the outstanding catalytic results, almost 100% removal degradation was achieved within 5 min over a wide pH value range at room temperature, which is better than that without catalysts. Temperature is a positive factor for improving the degradation rate, but room temperature is selected as the best temperature for economic and energy savings reasons, because more than 98% of fuchsins can still be degraded at room temperature. Moreover, these Fe₃O₄/SiO₂ core-shell nanoparticles exhibit excellent magnetic recyclability and stable properties after repeated utilization. Therefore, these as-presented Fe₃O₄/SiO₂ core-shell nanoparticles with low-cost and high performance are expected to be applied in practical industry wastewater degradation.

Insights into the efficient charge separation and transfer efficiency of La,Cr-codoped SrTiO3 modified with CoP as a noble-metal-free co-catalyst for superior visible-light driven photocatalytic hydrogen generation

Doped SrTiO₃ modified with CoP as a co-catalyst for photocatalytic H₂ evolution was designed and fabricated in this work.

Silicate silver/flower-like magnalium hydroxide composites for enhanced visible light photodegradation activities

Flower-like magnalium layered composites (MgAl-LDH) were first fabricated by a hydrothermal method, and a series of AgSiO_x/MgAl-LDH composites with different mole ratios was successfully prepared by loading AgSiO_x on the MgAl-LDH surface. The photocatalytic activities of the composites for the degradation of methylene blue (MB) were investigated under visible light irradiation (xenon lamp). The prepared AgSiO_x/MgAl-LDH composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy, thermogravimetric analysis (TG), and X-ray photoelectron spectroscopy (XPS). The results revealed that AgSiO_x/MgAl-LDH (5 : 1) displayed a photocatalytic degradation efficiency of 99.7% in 30 min for MB. The photocatalytic degradation rate was higher than that of pure AgSiO_x.

Flower-like magnalium layered composites (MgAl-LDH) were first fabricated by a hydrothermal method, and a series of AgSiO_x/MgAl-LDH composites with different mole ratios was successfully prepared by loading AgSiO_x on the MgAl-LDH surface.

In-situ synthesis of amorphous silver silicate/carbonate composites for selective visible-light photocatalytic decomposition

Coupling two different semiconductors to form composite photocatalysts is an extremely significant technique for environmental remediation. Here, a one-step in-situ precipitation method has been developed to prepare amorphous silver silicate/carbonate (AgSiO/Ag₂CO₃) nanoparticles (NPs) composites, which are well dispersed sphere-like particles with the sizes of around ~50–100 nm. The high-efficiency photocatalytic activities under visible light (VL) have been carefully evaluated, and the AgSiO/Ag₂CO₃ NPs composites exhibit selective photocatalytic degradations on Methylene Blue (MB) and Rhodamine B (RhB). The maximum degradation rate for MB can reach ~99.1% within ~40 min under VL irradiation, much higher than that of RhB (~12%) in the same condition, which can be ascribed to (I) the smaller molecule size of MB than that of RhB, (II) the fast charge separation between AgSiO NPs and Ag₂CO₃ NPs, abundant heterojunction interfaces as well as fully exposed reactive sites. These composites are proposed to be an example for the preparation of other silicate composite photocatalysts for practical applications in environmental remediation.

Dimensional heterostructures of 1D CdS/2D ZnIn2S4 composited with 2D graphene: designed synthesis and superior photocatalytic performance

Multidimensional heterostructure of 1D/2D CdS/ZnIn₂S₄ with 2D RGO are successfully synthesized, which exhibit superior photoactivity and good stability for the degradation of organic dyes.

Designed synthesis and surface engineering strategies of magnetic iron oxide nanoparticles for biomedical applications

Iron oxide nanoparticles (NPs) hold great promise for future biomedical applications because of their magnetic properties as well as other intrinsic properties such as low toxicity, colloidal stability, and surface engineering capability. Numerous related studies on iron oxide NPs have been conducted. Recent progress in nanochemistry has enabled fine control over the size, crystallinity, uniformity, and surface properties of iron oxide NPs. This review examines various synthetic approaches and surface engineering strategies for preparing naked and functional iron oxide NPs with different physicochemical properties. Growing interest in designed and surface-engineered iron oxide NPs with multifunctionalities was explored in in vitro/in vivo biomedical applications, focusing on their combined roles in bioseparation, as a biosensor, targeted-drug delivery, MR contrast agents, and magnetic fluid hyperthermia. This review outlines the limitations of extant surface engineering strategies and several developing strategies that may overcome these limitations. This study also details the promising future directions of this active research field.

Mesoporous iron oxide nanowires: synthesis, magnetic and photocatalytic properties

Controlled synthesis of mesoporous iron oxide nanowire nanohybrids with enhanced visible light-driven photocatalytic activity.