Highest Degradation Efficiency Research Articles

Short-term study of biological degradation of diesel oil by bacteria isolated from petroleum-contaminated soil

The use of fossil fuels leads to environmental contamination during their extraction, processing and distribution. Microbial biodegradation provides a sustainable method for cleaning contaminated areas which follows the principles of sustainability. This paper presents the dynamics of biodegradation of hydrocarbon fractions of diesel oil, using Planomicrobium sp. and Rhodococcus sp. isolated from petroleum-contaminated sites. GC–MS analysis was employed to analyse abundances of the specific compounds such as n-alkanes, isoprenoids, sesquitepranes, hopanes, steranes and aromatic compounds (naphthalene and its methylated homologues, phenanthrene and anthracene and their methylated homologues, and dibenzothiophene and its methylated homologues). The obtained results showed that after 30 days of biodegradation of diesel, a significant degradation was achieved, with almost complete degradation of n-alkanes and a decrease in the amount of sesquiterapanes. Rhodococcus sp. had a higher efficiency in degradation of n-alkanes, while Planomicrobium sp. had a higher efficiency in the degradation of branched hydrocarbons. Both strains showed high activity in the biodegradation of sesquitepranes and demonstrate ability to degrade methylated phenanthrenes. Additionally, dimethyl-dibenzothiophenes were almost completely degraded and removed from the system. This study presents the first comprehensive report on the GC–MS analysis of the diesel biodegradation pattern of the Planomicrobium sp., compared with the well-established Rhodococcus sp.

Directional Formation of Reactive Oxygen Species Via a Non-Redox Catalysis Strategy That Bypasses Electron Transfer Process.

A broad range of chemical transformations driven by catalytic processes necessitates the electron transfer between catalyst and substrate. The redox cycle limitation arising from the inequivalent electron donation and acceptance of the involved catalysts, however, generally leads to their deactivation, causing substantial economic losses and environmental risks. Here, a "non-redox catalysis" strategy is provided, wherein the catalytic units are constructed by atomic Fe and B as dual active sites to create tensile force and electric field, which allows directional self-decomposition of peroxymonosulfate (PMS) molecules through internal electron transfer to form singlet oxygen, bypassing the need of electron transfer between catalyst and PMS. The proposed catalytic approach with non-redox cycling of catalyst contributes to excellent stability of the active centers while the generated reactive oxygen species find high efficiency in long-term catalytic pollutant degradation and selective organic oxidation synthesis in aqueous phase. This work offers a new avenue for directional substrate conversion, which holds promise to advance the design of alternative catalytic pathways for sustainable energy conversion and valuable chemical production.

All‐In‐One Self‐Floating Wood‐Based Solar‐Thermal Evaporators for Simultaneous Solar Steam Generation and Catalytic Degradation

AbstractSolar‐driven steam generation has emerged as a sustainable technology for addressing freshwater scarcity. However, significant challenges still exist in developing high‐performance, multifunctional evaporators that are adept at both efficiently evaporating water and degrading pollutants, primarily because of the trade‐offs among functional designs. Here, a self‐floating solar evaporator is reported by functionalizing balsa wood with solar‐thermal conversion material carbon nanotubes and catalytic manganese dioxide (MnO2) nanoflowers for simultaneous solar evaporation and pollutant degradation. MnO2 nanoflowers are rich in oxygen vacancies that can effectively activate peroxymonosulfate to generate reactive oxygen species for efficient organic pollutant degradation. A distinctive non‐wetted porous interior structure and a precisely targeted water pathway are spontaneously established in the multifunctional evaporator, ensuring fast water supply, thermal insulation, efficient mass transfer, and high buoyancy. The resulting evaporators successfully combine an impressive evaporation rate of 2.74 kg m−2 h−1, a high pollutant degradation efficiency (98.3% for 100 mg L−1 tetracycline and 97.4% for 200 mg L−1 Methyl orange), and stable self‐floating and self‐standing capabilities that ensure long‐term operation stability even in complex real‐world environments. This work provides an approach to design multifunctional solar evaporators, ensuring strong alignment with practical requirements while expanding their potential application scenarios.

Preparation of Newly Polymer-Coated Microbial Pellets and Their Adsorption and Degradation Properties for Oil-Containing Wastewater.

Water is the lifeblood of everything on earth, nourishing and nurturing all forms of life, while also contributing to the development of civilization. However, with the rapid development of economic construction, especially the accelerated process of modern industrialization, the pollution of oily sewage is becoming increasingly serious, affecting the ecological balance and human health. The efficient elimination of pollutants in sewage is, therefore, particularly urgent. In this paper, a core-shell microbial reactor (MPFA@CNF-SA-AM) was fabricated by using nanocellulose and sodium alginate (SA) particles embedded with microorganisms as the core and lipophilic and hydrophobic fly ash as the outer shell layer. Compared with that of free microorganisms and cellulose and SA aerogel pellets loading with microorganisms (CNF-SA-AM), which has a degradation efficiency of 60.69 and 82.89%, respectively, the MPFA@CNF-SA-AM possesses a highest degradation efficiency of 90.60% within 240 h. So that this self-floating microbial reactor has selective adsorption properties to achieve oil-water separation in oily wastewater and high effective degradation of organic pollutants with low cost. The adsorption curves of MPFA@CNF-SA-AM for diesel and n-hexadecane were studied. The results showed that the adsorption follows the Freundlich model and is a multimolecular layer of physical adsorption. In addition, the degradation mechanism of diesel oil was studied by gas chromatography-mass spectrometry. The results showed that diesel oil was selectively adsorbed to the interior of MPFA@CNF-SA-AM, and it was degraded by enzymes in microorganisms into n-hexadecanol, n-hexadecaldehyde, and n-hexadecanoic acid in turn, and finally converted to water and carbon dioxide. Compared with existing oily wastewater treatment methods, this green and pollution-free dual-functional core-shell microbial reactor has the characteristics of easy preparation, high efficiency, flexibility, and large-scale degradation. It provides a new, effective green choice for oily wastewater purification and on-site oil spill accidents.

Highly efficient degradation and detoxification of antibiotics over C–Dots/siderite heteroaggregates in photo-Fenton systems: The crucial role of C–Dots

The substantial presence of antibiotics in aquatic environments remains as a critical environmental issue that needs to be urgently addressed. In this study, mimetics of C–Dots/siderite heteroaggregates (CSI) were studied in a visible-light-responsive Fenton system as a platform for the degradation of antibiotics in contaminated water. By virtue of the excellent electron transfer of C–Dots, the sustained conversion cycles of Fe(II) → Fe(III) → Fe(II) in CSI were greatly accelerated, and meanwhile the H2O2 utilization was enhanced. The optimized CSI–3 nanocomposite displayed a prominent degradation efficiency towards a series of tetracycline analogs at ppb levels. Density functional theory (DFT) calculations indicated the excellent photo-Fenton catalytic performance of CSI originated from the increased d-band center and electron density, which considerably improves the utilization of H2O2. Both experimental and theoretical studies revealed that the correlated toxicity of degradation intermediates was significantly decreased. Additionally, a continuous flow device integrating the CSI photo-Fenton system maintained a high degradation efficiency after long-term treatment of simulated chlortetracycline wastewater. The presented work thereby confirms a spontaneous remediation process for the decontamination and detoxification of persistent organic pollutants under the action of heteroaggregates formed by engineered nanoparticles and natural minerals.

Enhanced photocatalytic activity of porous TiO2 containing C/P/K derived from grapefruit peel.

Grapefruit peel possesses a porous structure and a significant specific surface area. In this study, we introduce an innovative and eco-friendly approach for synthesizing porous TiO2. This was accomplished by employing grapefruit peel as a bio-template and tetrabutyl titanate as the precursor, utilizing a two-step rotary impregnation-calcination process. The TiO2 faithfully reproduced the structural characteristics of the grapefruit peel across different scales, simultaneously incorporating C, P, K elements from the original grapefruit peel into the final samples. The fabricated samples were analyzed using XRD, XPS, SEM, TEM, BET, and UV-vis DRS. The results showed that the TiO2 displays an anatase phase, and possesses a high specific surface area. The investigation of photocatalytic performance demonstrated that the CPK-TiO2-10 sample exhibited outstanding photocatalytic activity against Rhodamine B (RhB) solution, achieving complete degradation within 60 minutes. Additionally, the total organic carbon (TOC) removal rate reached 91.34% after 60 minutes of irradiation. The sample maintained a high degradation efficiency, even after five recycling cycles. This exceptional performance can be attributed to its porous structure, enriched with pores and a larger surface area, as well as the beneficial effects of doping with C, P, K elements in TiO2.

A sustainable electrochemical strategy utilizing pulsed alternating current and dual carbon felt electrodes for enhanced degradation of organic pollutants: Oxidation performance and mechanisms

In this work, a novel electrochemical (EC) oxidation system utilizing pulsed alternating current (PAC) and dual carbon felt (CF) electrodes has been established for sustainable degradation of sulfamethoxazole (SMX) with no addition of extra oxidant. The EC/PAC system showed high degradation efficiency and energy efficiency compared to the pulsed direct current (PDC) and direct current (DC) systems. The EC/PAC process was effective across a wide pH range of 3–11 for SMX removal. The results showed that the 1O2 confined to the CF electrode surface was the dominant oxidative specie that was generated from dissolved oxygen in the system. Under PAC conditions, the cathode and anode were rapidly switched on the same CF electrode, increasing the generation of 1O2 for enhanced SMX oxidation. Furthermore, the EC/PAC system demonstrated resistance to interference from various anions of different concentration levels found in natural environment. In contrast to the EC/PDC system, the EC/PAC system emerged as a promising option for more efficient H2O2 production. High-resolution mass spectrometry results revealed the SMX degradation pathways and byproducts, which were then evaluated for toxicity removal. Overall, the EC/PAC system offers a green and sustainable solution to future wastewater treatment, with high degradation rates, energy efficiency, and sustainability.

Tailoring the surface functional groups of biochar for enhanced adsorption and degradation of pharmaceutically active compounds

In this study, orange peel biochar (OPBC) was synthesized through a pyrolysis process. Decoration with two specific functional groups (i.e., –COOH and NH2) was performed through a ball milling-assisted modification process to yield the respective biochars (i.e., OPBC-COOH and OPBC-NH2). Both OPBC-COOH and OPBC-NH2 demonstrated excellent adsorption capacities for sulfamethoxazole (SMX) and carbamazepine (CBZ), and hydrogen bonding between the pharmaceuticals and BCs followed the primary adsorption mechanism. In addition, both OPBC-COOH and OPBC-NH2 (0.3 g/L) exhibited high degradation efficiencies for SMX (10 mg/L, 87 %; 92 %) and CBZ (10 mg/L, 73 %; 83 %) when peroxymonosulfate (PMS, 1 mM) was present. The scavenging experiments confirmed that electron transfer and radical/non-radical pathways (·OH and 1O2) are mainly responsible for the degradation of SMX and CBZ, respectively. It was also proven that the oxygen- and nitrogen-containing surface functional groups on BC are important for activating PMS for the degradation of organic pollutants. These findings provide new insights into the effects of functional groups on BC for the degradation of contaminants of emerging concern.

A solid-state pulse power sub-nanosecond SiC DSRD-based generator with high-voltage and high repetition frequency for pulse discharge water treatment

Water treatment is one of the most important issues for all walks of life around the world. The unique advantages of the solid-state power electronic pulses in water treatment make it attractive and promising in practical applications. The output voltage, rising time, repetition rate, and peak power of output pulses have a significant impact on the effectiveness of water treatment. Especially in pulse electric field treatment and pulse discharge treatment, the pulse with fast rising time achieves the advantage of generating plasma without corona, which can avoid water heating effect and greatly improve the efficiency of the pulse generator. High repetition rate can significantly reduce the peak power requirement of the pulse in water treatment application, making the equipment smaller and improving the power density. Therefore, the study developed a high-voltage high frequency sub-nanosecond pulse power generator (PPG) system for wastewater treatment. It adopts SiC DSRD (Drift Step Recovery Diode) solid-state switches and realize modular design, which can achieve high performance and can be flexible expanded according to the requirements of water treatment capacity. Finally, an expandable high-voltage PPG for water treatment is built. The output parameters of the PPG include output pulse voltage range from 1 to 5.28 kV, rise time <600 ps (20%–90%), repetition up to 1 MHz. The experiment results of PPG application for pulse discharge water treatment is presented. The results indicate that the proposed generator achieves high-efficiency degradation of 4-Chlorophenol (4-CP), which is one of the most common chlorophenol compounds in wastewater. From experiment, the homemade system can degrade 450 mL waste water containing 500 mg/L 4-CP in 35 min, with a degradation rate of 98%. Thereby, the requirement for electric field intensity decreased. Through the further quantitative analysis, the impact of frequency, voltage, and electrode spacing on the degradation effect of 4-CP is confirmed.

Preparation of modified wood-based metal nanoparticles synthesized in situ and efficient removal of organic pollutants from wastewater

Wood has excellent properties such as biodegradability, high reactivity and rich channel skeleton structure. However, the defects such as hole blockage and limited specific surface area limit the application of wood-based materials in wastewater treatment. Therefore, in this research, wood substrates (DTWS) were treated using a deep eutectic solvent method, which was able to remove both lignin and hemicellulose from wood. Wood-based carriers with high specific surface area and high chemical activity were formed. The DTWS-Ag material was formed by growing Ag nanoparticles (NPs) in wood channels by hydrothermal method. The results showed that with the increase of lignin and hemicellulose removal, the degradation performance of DTWS-Ag material showed a volcanic trend due to the interaction between Ag and the inner wall of the pipe. The pore size and the amount of Ag NPs are very important to the degradation rate of dye molecules. DTWS-4-Ag composite material makes wood pore diameter and Ag NPs production reach a high balance, so that it has the highest degree of reduction. DTWS-4-Ag showed high catalytic degradation efficiency and stability for methylene blue degradation, with the degradation efficiency up to 98.3%. This low-cost, renewable wood-based filter has high dye degradation efficiency and can be widely used in practical wastewater treatment.

Investigating a batch-flow photocatalytic LED system for diclofenac removal in wastewater treatment plants: Assessing the influence of reaction conditions on photocatalytic efficiency

This work introduces an innovative batch-flow photocatalytic LED system aimed at efficiently removing diclofenac from wastewater. The study highlights the novelty of fabricating TiO2-loaded carbon fiber photocatalysts through a hydrothermal process, exhibiting a blue shift in their absorption spectrum and enhancing their photon absorption capability. A crucial design feature is the spectral matching between the LED light source and the photocatalyst, which is critical for achieving high photodegradation efficiency. A significant innovation of our study is the testing of the system under real conditions at an operational sewage treatment plant. Here, the designed system demonstrated high efficacy in degrading diclofenac across various treatment stages, highlighting its robustness and adaptability to changing environmental conditions. The highest degradation efficiency was achieved with sewage from the secondary settling tank, where nearly 90 % efficiency was observed after 6 h of irradiation. Moreover, the use of renewable energy sources emphasizes the system's sustainability, presenting a greener alternative to traditional wastewater treatment methods. The investigation not only showcases the system's effectiveness in diclofenac degradation but also its adaptability and stability under real-world conditions, marking a significant advancement in sustainable wastewater treatment technologies.

Controllable construction of hollow Fe3O4/Ag particles for microwave absorption and photocatalysis

Hollow metallic composite particles are widely used in microwave absorption and catalysis due to their unique cavity structures, and favorable physical and electromagnetic properties. In this work, we propose an approach to prepare highly dispersed Fe3O4/Ag composite particles with a hollow structure using water-soluble green template method combined with in-situ growth process. The as-prepared cubic Fe3O4/Ag composite particles with an average size of 3.19 μm of hollow Ag and 11.65 nm of Fe3O4 coating on the surface were used as fillers for preparing microwave absorption epoxy resin films, showing a minimum reflection loss of −62.37 dB at 16.63 GHz with 7.5 mm thickness. An effective absorption bandwidth of 4.80 GHz can be observed in the frequency bands of 4.70–6.09 and 14.59–18.00 GHz. This mechanism is attributed to the internal cavity of the Fe3O4/Ag particles realizing multiple reflections of electromagnetic waves, and the synergistic effect of Fe3O4 and Ag. Moreover, this perspective is confirmed by their photocatalytic performance. The Fe3O4/Ag particles achieve a high photocatalytic degradation efficiency of 99.84 % for Congo red dye within 30 min of light exposure and maintain a value of 96.62 % after 6 cycles, demonstrating an outstanding reusability.

Construction of CuFe2O4/Bi2MoO6 heterogeneous catalyst for high-efficiency photocatalytic degradation of levofloxacin under visible light: Mechanism, pathways and DFT calculation

The utilization of solar energy to stimulate semiconductor photocatalytic degradation is a sustainable method for environmental remediation. CuFe2O4/Bi2MoO6 was synthesized for the degradation of levofloxacin by successfully loading CuFe2O4 nanoparticles on the surface of Bi2MoO6 microflower by a simple sol-gel and hydrothermal method. Comprehensive characterizations confirmed the formation of a heterojunction structure between CuFe2O4 and Bi2MoO6. Owning to the strong synergistic effect between CuFe2O4 and Bi2MoO6, involving higher surface area and pore volume, multiple metal ion reaction centers enriched the charge transfer pathways, heterojunction structure facilitated charge migration and reduced electron-hole complexation, the optimal CBM-10 composite catalysts showed high degradation efficiency of LVF with 95.1% in 60min, and robust structural stability after five cycle experiments. The free radical scavenging test and DFT calculations revealed that three possible reaction pathways for photocatalytic degradation of LVF by combining the analysis of intermediates by HPLC-MS and h+, •O2- and •OH free radical were the main active species.

Improved Expression of Cerrena unicolor Laccase in Aspergillus niger via Combined Strategies and Its Applications

The application of laccases in biotechnology and industry is an expanding research field. Laccases derived from Cerrena unicolor (C. unicolor) exhibit notable potential in the food and industrial sectors. However, generating sufficient yields of this laccase through heterologous expression to meet commercial demands remains a challenge. Therefore, we heterologously expressed LACCASE2 (Lac2), a laccase gene from C. unicolor, in Aspergillus niger. By incorporating strategies such as codon optimization, molecular chaperone-assisted expression, and atmospheric and room-temperature plasma (ARTP) mutagenesis, we successfully screened the strain OPT-HacA-M10 with the highest laccase yield, which exhibited a remarkable enzymatic activity of 416.8U/mL in a 50-L fermenter. We further assessed the enzymatic properties of the recombinant laccase rLac2, focusing on its capabilities in dye decolorization and mycotoxin degradation. In the absence of a mediator, rLac2 exhibited extremely high degradation efficiency for Remazol Brilliant Blue R and indigo. Impressively, outstanding results were achieved with this laccase in denim bleaching. In mycotoxin degradation tests, with methyl syringate as a mediator, rLac2 achieved degradation rates of over 94% for aflatoxin B1 and zearalenone. In summary, due to its heightened laccase activity and versatile applications, our enhanced strain is highly suitable for industrial and food sectors.

Fully bio-based intumescent flame retardant hybrid: A green strategy towards reducing fire hazard and improving degradation of polylactic acid

Polylactic acid (PLA) is a promising renewable polymer material with excellent biodegradability and good mechanical properties. However, the easy flammability and slow natural degradation limited its further applications, especially in high-security fields. In this work, a fully bio-based intumescent flame-retardant system was designed to reduce the fire hazard of PLA. Firstly, arginine (Arg) and phytic acid (PA) were combined through electrostatic ionic interaction, followed by the introduction of starch as a carbon source, namely APS. The UL-94 grade of PLA/APS composites reached V-0 grade by adding 3 wt% of APS and exhibited excellent anti-dripping performance. With APS addition increasing to 7 wt%, LOI value increased to 26 % and total heat release decreased from 58.4 (neat PLA) to 51.1 MJ/m2. Moreover, the addition of APS increased its crystallinity up to 83.5 % and maintained the mechanical strength of pristine PLA. Noteworthy, APS accelerated the degradation rate of PLA under submerged conditions. Compared with pristine PLA, PLA/APS showed more apparent destructive network morphology and higher mass and Mn loss, suggesting effective degradation promotion. This work provides a full biomass modification strategy to construct renewable plastic with both good flame retardancy and high degradation efficiency.

3D-TNAs/N-TiO2 photoanode assisted heterogeneous electro-Fenton with a novel Fe-MOFs@CF cathode for efficient synergetic oxidation of organic contaminants

Photoelectro-catalysis (PEC) and heterogeneous electro-Fenton (HEF) reactions are two frontier research fields for real effluent treatments. In the present work, a synergetic system with integration of both PEC and HEF has been developed for pollutant removal. PEC process with lower external bias results in the efficient separation of photogenerated hole and electrons, which can also modulate the HEF catalytic performance at the counter electrode, and in other cases the active HEF reaction can in turn affect the intrinsic activity of PEC. In this system, three dimensional TiO2 nanotube arrays coupled with nitrogen doped TiO2 nanoparticles (3D-TNAs/N-TiO2) was prepared as photoanode for solar light-driven PEC process while NH2-MIL-101 loaded on carbon felt (Fe-MOFs@CF) have been used as the cathode for HEF reaction. The performances of the synergetic system showed much higher degradation efficiency, which were evaluated by degrading typical organic containments in water (with the best of∼95 % in 5 min with 2*3 cm2 electrode area). The reaction rate in the coupling system were ∼7.25 and 1.18 times higher than single PEC or HEF with a wide pH applied range, well recycled and good stability for further application in water purification.

Resource utilization of MSWI fly ash supporting TiO2/BiOCl nanocomposite for enhanced photocatalytic degradation of sodium isopropyl xanthate: Mechanism and performance evaluation

The removal of organic pollutants in water environments and the resource utilization of solid waste are two pressing issues around the world. Facing the increasing pollution induced by discharge of mining effluents containing sodium isopropyl xanthate (SIPX), in this work, municipal solid waste incineration fly ash (MSWI FA) was pretreated by hydrothermal method to produce stabilized FA, which was then innovatively used as support for the construction of FA/TiO2/BiOCl nanocomposite (FTB) with promoted photocatalytic activity under visible light and natural sunlight. When the content of FA was 20 wt% and the mass ratio of TiO2 to BiOCl was 4:6, a remarkable performance for the optimal FTB (20-FTB-2) was achieved. Characterizations demonstrated that TiO2 and BiOCl uniformly dispersed on FA contributing to high surface area and broad light adsorption of FTB, which exhibits excellent adsorption capacity and light response ability. Build in electric field formed in the interface of TiO2/BiOCl heterojunction revealed by density functional theory calculations accelerated the separation of photoinduced e− and h+, leading to high efficiency for SIPX degradation. The synergetic effect combined with adsorption and photocatalytic degradation endowed 20-FTB-2 superior SIPX removal efficiency over 99% within 30 min under visible light and natural sunlight irradiation. The photocatalytic degradation pathways of SIPX were determined through theoretical calculations and characterizations, and the toxic byproduct CS2 was effectively eliminated through oxidation of •O2−. For 20-FTB-2, reusability of photocatalyst was showed by cycle tests, also the concentrations of main heavy metals (Pb, Zn, Cu, Cr, and Cd) in the liquid phases released during photocatalyst preparation process (< 1 mg/L) and photodegradation process (< 8.5 μg/L) proved the satisfactory stability with low toxicity. This work proposed a novel strategy to develop efficient and stable support-based photocatalysts by utilizing MSWI FA and realize its resource utilization.

Enhancement of Peroxydisulfate Activation for Complete Degradation of Refractory Tetracycline by 3D Self-Supported MoS2/MXene Nanocomplex.

Antibiotic abuse, particularly the excessive use of tetracycline (TC), a drug with significant environmental risk, has gravely harmed natural water bodies and even posed danger to human health. In this study, a three-dimensional self-supported MoS2/MXene nanohybrid with an expanded layer spacing was synthesized via a facile one-step hydrothermal method and used to activate peroxydisulfate (PDS) for the complete degradation of TC. The results showed that a stronger •OH signal was detected in the aqueous solution containing MoS2/MXene, demonstrating a superior PDS activation effect compared to MoS2 or Ti3C2TX MXene alone. Under the conditions of a catalyst dosage of 0.4 g/L, a PDS concentration of 0.4 mM, and pH = 5.0, the MoS2/MXene/PDS system was able to fully eliminate TC within one hour, which was probably due to the presence of several reactive oxygen species (ROS) (•OH, SO4•-, and O2•-) in the system. The high TC degradation efficiency could be maintained under the influence of various interfering ions and after five cycles, indicating that MoS2/MXene has good anti-interference and reusability performance. Furthermore, the possible degradation pathways were proposed by combining liquid chromatography-mass spectrometry (LC-MS) data and other findings, and the mechanism of the MoS2/MXene/PDS system on the degradation process of TC was elucidated by deducing the possible mechanism of ROS generation in the reaction process. All of these findings suggest that the MoS2/MXene composite catalyst has strong antibiotic removal capabilities with a wide range of application prospects.

Photocatalytic degradation of ammonia to nitrogen by anatase TiO2 under microwave discharge electrodeless lamp irradiation

In this study, a microwave discharge electrodeless lamp (MDEL) photo-degradation system coupled with anatase TiO2 (P25) was constructed to improve the selective degradation of NH3 to N2. The MDEL system can generate abundant reactive oxygen species (ROS) with ultraviolet radiation at 185 nm and 254 nm during gas phase reaction. The species and content of ROS generated in the reaction system were determined by oxidation extraction spectrophotometry, and the effects of residence time, temperature, and relative humidity on the production of reactive oxygen species were investigated. In addition, the removal efficiency under different conditions such as initial ammonia concentration, relative humidity and residence time was explored. It was found that the removal rate could reach 83% when the initial ammonia concentration was 100 ppm, relative humidity was 55% and gas residence time was 5.16 s. The high-energy ultraviolet at 185 nm from MDEL could break NH3 molecules in advance and produced a large amount of ·NH2. Besides, NH3 was converted to N2 by generating large amounts of ROS, reducing NOx and nitrate generation. Our work presents a novel approach to construct a photocatalytic system for high efficiency degradation of NH3.

Photocatalytic degradation of methylene blue by TiO2/Nd2O3 composite thin films

To improve the photocatalytic property of TiO2 thin films, the composite thin films of TiO2/Nd2O3 structure were fabricated by electron-beam physical vapor deposition method, and the photocatalytic property of the fabricated films was experimentally studied in the present work. The XRD and Raman analyses show that the TiO2/Nd2O3 films are mainly hexagonal crystalline phase of Nd2O3. The XPS analysis for the chemical state changes of Ti, O and Nd of the basic elements in the films is confirming the electron flow in the internal electric field which generated in the TiO2/Nd2O3 films. The surface morphology shows the lattice distortion which affects the changes in the energy band structure. Moreover, the formation of n-n homojunctions improved the separation efficiency of electrons and holes, and enhanced the catalytic activity. The photocatalytic performance for the methylene blue target dye shows that the sample with TiO2 thickness of 20–25 nm has better performance, high degradation efficiency and high reaction rate.