Morphophysiological changes of Acca sellowiana (Myrtaceae: Myrtoideae) saplings under shade gradient / Alterações morfofisiológicas em mudas de Acca sellowiana (Myrtaceae: Myrtoideae) sob gradiente de sombreamento

Abstract Understanding morphological and physiological changes under different light conditions in native fruit species in juveniles' stage is important, as it indicate the appropriate environment to achieve vigorous saplings. We aimed to verify growth and morphophysiological changes under shade gradient in feijoa (Acca sellowiana (O. Berg) Burret) to achieve good quality saplings adequate to improve cultivation in orchards. The saplings were grown for twenty-one-month under four shading treatments (0%, 30%, 50%, and 80%). Growth, photosynthetic pigments, gas exchanges, chlorophyll fluorescence, and leaf anatomy parameters were evaluated. Saplings under full sun and 30% shade had higher height and diameter growth and dry mass accumulation due to higher photosynthesis rate. As main acclimatization mechanisms in feijoa saplings under 80% shade were developed larger leaf area, reduced leaf blade thickness, and enhanced quantum yield of photosystem II. Even so, the net CO2 assimilation and the electron transport rate was lower and, consequently, there was a restriction on the growth and dry mass in saplings under deep shade. Therefore, to obtain higher quality feijoa saplings, we recommend that it be carried out in full sun or up to 30% shade, to maximize the sapling vigor in nurseries and, later, this light environment can also be used in orchards for favor growth and fruit production.

Resumo A verificação de mudanças morfológicas e fisiológicas sob diferentes condições luminosas em espécies frutíferas nativas em estágio juvenil é importante, uma vez que indicam o ambiente adequado para a formação de mudas com alto vigor. Objetivou-se verificar o crescimento e as alterações morfofisiológicas sob gradiente de sombreamento em mudas de feijoa (Acca sellowiana (O. Berg) Burret) para obter mudas de boa qualidade, adequadas para fomentar os plantios da espécie em pomares. As mudas foram cultivadas por vinte e um meses sob quatro tratamentos de sombreamento (0%, 30%, 50% e 80%). Foram avaliados parâmetros de crescimento, pigmentos fotossintéticos, trocas gasosas, fluorescência da clorofila e anatomia foliar. Mudas a pleno sol e 30% de sombra apresentaram maior crescimento em altura, diâmetro e acúmulo de massa seca, devido à maior taxa de fotossíntese. Como principais mecanismos de aclimatação sob 80% de sombra, as mudas desenvolveram maior área foliar, redução da espessura do limbo foliar e aumento do rendimento quântico do fotossistema II. Mesmo assim, a assimilação líquida de CO2 e a taxa de transporte de elétrons foram menores e, consequentemente, houve restrição ao crescimento e acúmulo de massa seca das mudas no maior nível de sombreamento. Portanto, para a obtenção de mudas de feijoa de maior qualidade, recomendamos que seja realizada a pleno sol ou até 30% de sombra, para maximizar o vigor das mudas em viveiros e, posteriormente, este ambiente de luz também pode ser utilizado em pomares para favorecer o crescimento e a produção de frutos.

Engineering Green-light-responsive Heterologous Gene Expression in Pseudomonas.

Engineering bacterial properties requires precision and fine-tuning for optimal control of the desired application. In consequence, it is essential to accurately turn the function of interest from OFF to ON state and vice versa, avoiding any type of residual activation. For this type of purpose, light switches have revealed a clean and powerful tool in which control does not depend on the addition of chemical compounds that may remain in the media. To reach this degree of directed regulation through light, the switch based on the cyanobacterial two-component system CcaSR system was previously adapted to manipulate Pseudomonas putida for transcription of a gene of interest. In this chapter, we describe how to induce biofilm formation by placing the expression of the c-di-GMP-producing diguanylate cyclase PleD from Caulobacter sp. under the control of the CcaSR system. The regulation through optogenetics accomplished with this protocol promotes higher exploitation of biofilm beneficial features in a cheaper and cleaner way compared to chemical induction.

Formation of di-Tyrosine in pasteurized milk during shelf storage.

Formation of the protein crosslink di-Tyrosine was studied in PET-bottled pasteurized milk exposed to fluorescent light in a commercial display cabinet. An HPLC method with fluorescence detection was developed and intra-laboratory validated using pure di-Tyrosine synthesized on purpose. Di-Tyrosine was detected after 1-day lightening and increased up to 7 days, reaching around 250 and 320 µg/g protein in whole and partly skimmed milk, respectively. Afterward, a progressive decrease occurred. By transmission electron microscopy with specific immune gold labelling, presence of di-Tyrosine was observed for the first time on the surface of casein micelles of lightened milk. The crosslink formation, however, did not bring to protein aggregation phenomena detectable by laser light scattering measurements. Exposure to light also induced degradation of riboflavin and decrease of yellowness index. Di-Tyrosine proved to be a suitable indicator to evaluate the progress of protein oxidation in pasteurized milk during storage on the market.

Photosensitization can be an effective risk-reduction strategy against the post-baking mold spoilage of bread.

Photosensitization was developed as a risk-reduction strategy against the contamination by environmental mold spores during the bread cooling phase. Two food-grade photosensitizers -chlorophyllin (CHL) and riboflavin (RBF), were used to evaluate the effect of visible (blue) LED illumination against three common bread spoilage molds. Aided by CHL, 405 nm LEDs inactivated Rhizopus stolonifer and Penicillium expansum by 77.4 ± 3.3% and 52.1 ± 7.3% respectively in 30 min on dichloran rose bengal chloramphenicol agar. These reductions were much higher than the corresponding reductions observed with food-grade RBF and 445 nm LEDs - 22.8 ± 3.2% and 45.5 ± 5.9%, indicating that CHL-based photosensitization was more effective as an intervention than RBF-based photosensitization. When the three molds were illuminated on bread after spraying CHL and spot-inoculation, their populations were reduced by 51-58%. CHL-based photosensitization was observed to retain the texture and moisture of the bread samples, but had a statistically significant impact on their colour. The results of this study suggest that CHL-based photosensitization can be developed as a risk reduction method to prevent the spoilage of bread.

"Floating Catalytic Foam" with prominent heat-induced convection for the effective photocatalytic removal of antibiotics.

Immobilized photocatalysts represent a promising candidate for the wastewater treatments due to their good reusability, high stability and low eco-risk. Mass transfer within the immobilized catalytic bed is a crucial process that determines the contacting, adsorption, and degradation kinetics in the photodegradation. In this study, a floating catalytic foam (FCF) with a prominent pumping effect was designed to promote mass transfer. The polyurethane foam immobilized with rGO/TiO2/ultrathin-g-C3N4 photocatalyst (PRTCN) was prepared by a simple dip-coating and Uv-light aging process. It was found that the hydrophilic-hydrophobic interfaces could not only contribute to the floating of the catalyst but also establish a temperature gradient across the floating immobilized catalyst. In addition, the temperature gradient induced convection could serve as a built-in pump to effectively promote the diffusion and adsorption of target antibiotic molecules during the photocatalytic process. Therefore, the PRTCN demonstrated a high photodegradation and mineralization efficiency with excellent reusability and anti-interference capability. Moreover, the photodegradation mechanism and the intermediates' toxicity of norfloxacin were detailly investigated by ultra-high resolution electrospray time-of-flight mass spectrometry, density functional theory simulation and ECOSAR estimation. This work proposed a facile and sustainable strategy to enhance the mass transfer problem on immobilized photocatalysts, which could promote the application of the immobilized photocatalysts in the real water-treatment scenarios.

Synergistic interface engineering in n-p-n type heterojunction Co3O4/MIL/Mn-STO with dual S-scheme multi-charge migration to enhance visible-light photocatalytic degradation of antibiotics.

Constructing an effective multi-heterojunction photocatalyst with maximum charge carrier separation remains challenging. Herein, a high-efficient Co3O4/MIL-88A/Mn-SrTiO3 (Co3O4/MIL/Mn-STO) n-p-n heterojunction photocatalyst was successfully prepared by a simple hydrothermal method for the photodegradation of sulfamethoxazole (SMX). The combination of MIL and Co3O4/Mn-STO established an internal electric field and heterojunction, accelerating the separation of carriers, and thus improved photocatalytic performance. In the Co3O4/MIL/Mn-STO photocatalytic system, 95.5 % of SMX was degraded in 90 min. The photocatalytic kinetic removal rate of Co3O4/MIL/Mn-STO reached 0.0337 min-1, 8 times of Co3O4 (0.0041 min-1), 5.2 times of Mn-STO (0.0062 min-1), 4.6 times of MIL (0.0078 min-1), and 3.6 times of MIL/Mn-STO (0.0095 min-1). Remarkably, superoxide radicals (•O2-) and holes (h+) have been recognized as the main active species in the degradation process through reactive species elimination experiments and electron spin resonance (ESR) tests. The experimental and theoretical proved the in-built interfacial contact and synergistic effect between the photocatalyst accomplished with low bandgaps, high specific surface area, more reaction sites, high electron-hole pair separation, and maximum solar-light utilization. The molecular structure and possible degradation routes with intermediate products in the photocatalytic system were investigated using a liquid chromatography-mass spectrometer (LC-MS) and DFT calculations. This work provided new insight into the guidelines of rational design/growth of new multicomponent photocatalysts to remove antibiotics and other emerging contaminants in wastewater.

Growth of Ag/g-C3N4 nanocomposites on nickel foam to enhance photocatalytic degradation of formaldehyde under visible light.

Formaldehyde is a pollutant that significantly affects the indoor air quality. However, conventional remediation approaches can be challenging to deal with low-concentration formaldehyde in an indoor environment. In this study, Photocatalysts of Ag/graphitic carbon nitride (g-C3N4)/Ni with 3D reticulated coral structure were prepared by thermal polymerization and liquid phase photo-deposition, using nickel foam (NF) as the carrier. Experiments demonstrated that when the Ag concentration was 3%, and the relative humidity was 60%, the Ni/Ag/g-C3N4 showed the maximum degradation rate of formaldehyde at 90.19% under visible light irradiation, and the formaldehyde concentration after degradation was lower than the Hygienic standard stated by the Chinese Government. The porous structure of Ni/Ag/g-C3N4 and the formation of Schottky junctions promoted the Adsorption efficiency and degradation of formaldehyde, while the nickel foam carrier effectively promoted the desorption of degradation products. Meanwhile, the degradation rate was only reduced by 3.4% after 16 recycles, the three-dimensional porous structure extended the lifetime of the photocatalyst. This study provides a new strategy for the degradation of indoor formaldehyde at low concentrations.

Review of low-cost light sources and miniaturized designs in photoacoustic microscopy.

Significance: Photoacoustic microscopy (PAM) is a promising imaging technique to provide structural, functional, and molecular information for preclinical and clinical studies. However, expensive and bulky lasers and motorized stages have limited the broad applications of conventional PAM systems. A recent trend is to use low-cost light sources and miniaturized designs to develop a compact PAM system and expand its applications from benchtop to bedside. Aim: We provide (1) an overview of PAM systems and their limitations, (2) a comprehensive review of PAM systems with low-cost light sources and their applications, (3) a comprehensive review of PAM systems with miniaturized and handheld scanning designs, and (4) perspective applications and a summary of the cost-effective and miniaturized PAM systems. Approach: Papers published before July 2023 in the area of using low-cost light sources and miniaturized designs in PAM were reviewed. They were categorized into two main parts: (1) low-cost light sources and (2) miniaturized or handheld designs. The first part was classified into two subtypes: pulsed laser diode and continuous-wave laser diode. The second part was also classified into two subtypes: galvanometer scanner and micro-electro-mechanical system scanner. Results: Significant progress has been made in the development of PAM systems based on low-cost and compact light sources as well as miniaturized and handheld designs. Conclusions: The review highlights the potential of these advancements to revolutionize PAM technology, making it more accessible and practical for various applications in preclinical studies, clinical practice, and long-term monitoring.

A novel multifunctional magnetically recyclable BiOBr/ZnFe2O4-GO S-scheme ternary heterojunction: Photothermal synergistic catalysis under Vis/NIR light and NIR-driven photothermal detection of tetracycline.

The threat of tetracycline (TC) to human health has become a significant issue that cannot be disregarded. Herein, in order to achieve effective degradation and high-sensitivity detection of TC, BiOBr/ZnFe2O4-GO (BOB/ZFO-GO) S-scheme heterojunction nanocomposites (NCs) have been prepared using hydrothermal method. GO with high light absorption capacity accelerated the electron transfer between BiOBr and ZnFe2O4 nanocrystals and extended the light absorption region of BOB/ZFO NCs. The optimal GO addition of BOB/ZFO-GO NCs could degrade TC solution of 10 mg/L in 80 min and have a high reaction rate constant (k) of 0.072 min-1 under visible/NIR light. According to calculations, the non-metal photocatalyst (BOB/ZFO-GO(2)) with the best degradation performance had a photothermal conversion efficiency of up to 23%. Meanwhile, BOB/ZFO-GO NCs could be recycled by magnetic field. The excellent photocatalytic and photothermal performance could be maintained even after several cycles. In addition, a photothermal detection sensor based on a photothermal material/specific recognition element/tetracycline sandwich-type structure was constructed for the trace detection of TC concentration with a detection limit as low as 10-4 ng/mL. This research provides a unique idea for the multi-functionalization of photocatalysts and has a wide range of potential applications for the identification and treatment of organic wastewater.

Evaluation of Cladophora and Chlamydomonas microalgae for environmental sustainability: A comparative study of antimicrobial and photocatalytic dye degradation.

The present study emphasizes exploring the potential of bioactive compounds such as polysaccharides, protein, pigments, antioxidants, and vitamins extracted from two microalgae species, Cladophora and Chlamydomonas. The extraction process was optimized for different periods, and the extracted bioactive compounds were characterized. These bioactive compounds showed significant antibacterial activity against gram-positive and gram-negative bacteria. Notably, Cladophora species exhibited a higher zone of inhibition than Chlamydomonas species against both gram-positive and gram-negative bacterial strains. Moreover, the photocatalytic activity of these bioactive compounds was investigated for the degradation of methylene blue and crystal violet dyes under different light conditions. The results demonstrated that Cladophora species exhibited superior photocatalytic activity under natural sunlight, UV light, and visible light sources compared to Chlamydomonas species. Moreover, Cladophora species achieved the highest dye degradation efficiencies of 78% and 72% for methylene blue and crystal violet, respectively, within 150 min compared to UV light and visible light sources.

Construction of a floating photothermal-assisted photocatalytic system with a three-dimensional hollow porous network structure.

Solar energy is the inevitable choice to achieve the low-carbon, green, and circular development of society, and photocatalysis technology is one of the shining pearls. To make full use of the solar spectrum and solve the shortcomings of the recovery difficulty of powdery materials and the loss of activity due to the influence of the external environment, it is possible to construct floating materials using melamine sponges to recover photocatalytic materials quickly. At the same time, floating materials can absorb oxygen in the air for the generation of active groups, effectively solving the problem of less O2 in the water. The carbon-based materials have excellent light absorption properties, high thermal conductivity, and excellent photothermal conversion efficiency and are ideal for constructing floating photothermal photocatalytic systems. As an example, we combined a cheap melamine sponge with urea, prepared a hollow porous network structure g-C3N4 (HPNCN) with a high specific surface area by direct thermal shrinkage method, and then attached the CoO to its surface by hydrothermal method to form a heterojunction with a suitable band gap. Various characterization tests verified the photothermal-photocatalytic properties. Among them, 30% CoO/HPNCN has the best photocatalytic degradation effect on tetracycline (TC), and the removal rate is 88.1%. After five cycles, the removal rate is only 5% lower than the initial, indicating that it has good stability and recyclability. We conducted an active ingredient capture experiment, ESR, and LC-MS analysis to clarify the intermediates and reaction mechanism of TC photocatalytic degradation. On this basis, the ECOSAR program and QSAR method were used to analyze the environmental toxicity of TC and its intermediate products. These results provide a broad prospect for the potential application of the floating photothermal-photocatalysis system in antibiotic pollution control and its application in other fields.

Sphere-rod-like Ag/AgCl@Fe2O3 Z-scheme heterojunction as photocatalysts for efficient degradation of tetracycline under visible light irradiation.

Integration of multi-functional components into one is urgent for creating a viable platform to improve photocatalytic efficiency for environmental treatment. Here, MIL-88B-NH2 (Fe) was firstly employed to capture Ag+ cation for the formation of AgCl@MIL-88B-NH2 (Fe), and then turned into the strongly coupled Ag/AgCl@Fe2O3 with sphere-rod-like structure. As prepared Z-scheme Ag/AgCl@Fe2O3 heterojunction exhibited outstanding photocatalytic performance of tetracycline (TC) with a removal efficiency of 94.9% and a reaction kinetics of 0.0272 min-1, superior to single Ag/AgCl or Fe2O3, which attributed to the broad light absorption range and accelerated electron-hole pair separation stemmed from the synergistic effect between surface plasmon resonance effect (SPR) of metal Ag and AgCl/Fe2O3 heterojunction. Meanwhile, Ag/AgCl@Fe2O3 was found to be highly catalytic in the degradation of TC even after consecutive runs. Moreover, active species trapping experiments combined with ESR techniques revealed that superoxide radical, hydroxyl radical, electron, and hole all were involved in photodegradation of TC process. Importantly, the degradation intermediate products of TC were revealed in depth by LC-MS, and a possible degradation pathway was further proposed. This work opens up new insights into the integration of functional composites for the construction of advanced photocatalysts applied in environmental purification.

Constructing a novel type-â ¡ ZnO/BiOCOOH heterojunction microspheres for the degradation of tetracycline and bacterial inactivation.

A novel ZnO/BiOCOOH microsphere photocatalyst with a type-Ⅱ mechanism was developed for the first time. This strategy was accomplished by immobilizing ZnO onto 3D BiOCOOH microspheres via a single-step hydrothermal synthesis method. The ability to degrade tetracycline (TC) in water under visible light and inactivate bacteria of as-catalyst were analyzed. Among the prepared samples, the ZnO/BiOCOOH composite, with a mass ratio of 40%(Zn/Bi), exhibited the highest photocatalytic activity, which was able to degrade 98.22% of TC in just 90 min and completely eradicated Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in 48 h, and had potential application in solving water resource environmental pollution. The photoelectric characteristics of the photocatalysts were examined by means of electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) spectroscopy. The findings indicated that the superior photocatalytic performance could be credited to the dissociation of electrons (e-) and holes (h+) in heterojunction composites. Finally, electron paramagnetic resonance (EPR) and capture experiments were conducted to confirm the photocatalytic mechanism of the type-Ⅱ heterojunction. This work provides a new Bi-base photocatalyst for aqueous environmental control.

Low intensity magnetic separation of vivianite induced by iron reduction on the surface layer of Fe(III)[Fe(0)] iron scrap.

Phosphorus (P) recovery through vivianite, which can be found in activated sludge, surplus sludge and digested sludge in the wastewater treatment plants (WWTPs), is a cutting-edge and efficient technology in recent years. However, how to generate and separate vivianite in an effective and economical way with natural iron oxide mineral was still the bottleneck to limit its application. Therefore, in this study, the P recovery efficiency (EP) and vivianite recovery efficiency (EV) of three kinds of iron oxides were investigated. We found that the EP of Akaganeite was 1.83 times and 4.88 times higher than that of Geothite and Hematite. Simultaneously, EV of Akaganeite was 1.64 times and 2.88 times higher than that of Geothite and Hematite. As Akaganeite is main component of rust on the surface of iron scrap, we used Fe(III)[Fe(0)] iron scrap with Fe(0) inside and Akaganeite outside as iron source and electron acceptor for vivianite production and magnetic separation. At the terminal stage (60 day), the P recovery efficiency with 20 g/L Fe(III)[Fe(0)] iron scrap was 36%. Applying a magnetical separator with magnetic field intensity of 0.3 T, vivianite was separated from the solution efficiently and immediately. Low intensity magnetic separation with iron scrap would recover P resources economically with the total cost to be $2.23/kg P, which was much lower than recovery via iron salts. Besides, it provided a significant insights into the P recovery and vivianite separation by reusing Fe waste during wastewater treatment.

Efficient removal of the recalcitrant metamizole contaminant from drinking water by using a CaLaCoO9 perovskite supported on recycled polyethylene.

Metamizole (MZ) is a widely used anti-inflammatory drug. Due to its common use, this contaminant is found in sewage and rivers. In order to reduce the contamination produced by the MZ, we fabricated in this work a photocatalytic composite using recycled polyethylene (RPE) and the CaLaCoO9 (LCCO) perovskite. Those nanoparticles had a microplate-like morphology and sizes of 1.4-5.5 µm according to the analysis of microscopy. The photocatalytic properties of the LCCO powders were evaluated under ultraviolet-visible (UV-Vis) irradiation and found a removal efficiency of 96%. When the RPE+LCCO composite was employed for the photocatalytic degradation of MZ, a maximum degradation of 92.5% was obtained. The influence of the pH on the photocatalytic activity was also studied and found that an initial pH = 3 produced a total degradation of MZ after 240 min of UV-Vis irradiation. Moreover, three reuse cycles were carried out for the pure LCCO powders and for the RPE+LCCO composites and found that the maximum loss of degradation was 5%. Furthermore, scavenger experiments demonstrated that the super oxide and hydroxyl radicals are formed during the photocatalytic reaction and were responsible for the degradation of MZ. Additionally, the X-ray photoelectron-spectroscopy and Raman analysis demonstrated the formation of defects (oxygen vacancies), those ones delayed the electron-hole recombination, which in turn, enhanced the degradation of the MZ. Thus, the studies performed in this work proved that composites made with recycled plastics and LCCO perovskites are a low-cost and feasible alternative for the cleaning of water sources polluted with pharmaceutical compounds.

Sterilization mechanism and nanotoxicity of visible light-driven defective carbon nitride and UV-excited TiO2.

The sterilization effect of photocatalysis and biotoxicity of nanomaterial catalysts have attracted high attention. In this study, the novel visible-driven defective carbon nitride (VL/DCN) system exhibits non-photoreactivation, non-toxic superior performance compared with traditional ultraviolet radiation (UV) and UV/titanium dioxide (UV/TiO2). The inactivation of antibiotic-resistant bacteria (ARB) by novel VL/DCN still reached 7 log within 4 h, and the reduction rates of aminoglycoside gene strB and tetracycline gene tetA exceeded 0.8 log and 1.2 log, respectively. Further, the sterilization mechanism and nanotoxicity were contrastively and systematically analyzed among above three systems as following. Firstly, in the VL/DCN system, reactive oxygen species (ROSs) generated from photocatalytic process leads to the destruction of cell membranes, resulting in dissolving out of potassium ion (K+), protein and cell membrane ATP content. Thus, resistant bacteria were completely inactivated and photoreactivation disappears. In contrast, the UV only acted on bacterial DNA and existed the light resurrection. The UV/TiO2 strictly dependent on ultraviolet light and can be used in limited scenarios. Secondly, in cell viability analysis by human lung cell line BEAS-2B experiments, the 10% inhibition of cell growth when DCN was 600 mg/L much lower than 28% inhibition of cell growth when TiO2 was only 200 mg/L. The expression of pro-inflammatory cytokines ((Interleukin, IL) -6), IL-8, IL-1ß) under the effect of DCN was 1.5-fold, 5.7-fold and 3.7-fold lower than TiO2, respectively. Meanwhile, DCN induced cells to produce less ROSs, malondialdehyde (MDA), and more superoxide dismutase (SOD). Above results demonstrated that DCN has far lower cytotoxicity than TiO2. This study provides theoretical support for the application of photocatalytic sterilization technology and the exploration of the toxicity of nanomaterials.

An ultra-porous g-C3N4 micro-tube coupled with MXene (Ti3C2TX) nanosheets for efficient degradation of organics under natural sunlight.

It remains as a challenge for realizing efficient photo-responsive catalysts towards large-scale degradation of organic pollutants under natural sunlight. This work reports a new pore engineering strategy for creating ultra-porous g-C3N4 micro-tubes with an unprecedentedly high specific surface area of 152.96 m2/g. This is mainly associated with releasing internal vapor pressure in the autoclave where the hydrothermal treatment of the urea/melamine mixture is processed. Supported by microscopic observation, porosity measurement and spectroscopic characterization, it is found that releasing the pressure at halfway of hydrothermal process is vital for forming exfoliated rod-like precursors and the de-aggregation of these rods presents substantial benefits on the production of mesopores on g-C3N4 micro-tubes during the calcination of precursors. This offers a large number of reactive sites required by photocatalytic reaction. Coupling these micro-tubes with Ti3C2TX nanosheets via electrostatic interaction yields a 1D/2D heterojunction with a close interfacial contact. The addition of metallically conductive Ti3C2TX nanosheets accelerates the separation between electrons and holes, and also enhances the light absorption. All these merits of structural design lead to forming a group of highly efficient catalysts demonstrating an excellent photocatalytic degradation rate of k = 0.0560 min-1 for RhB dyes under 100 mW/cm2 visible light radiation that micks sunlight outdoors. This laboratory valuation is further supported by an outdoor test that shows a fast degradation rate of 0.0744 min-1 under natural sunlight.

Visible light-driven oxidation of non-native substrate by laccase attached on Ru-based metal-organic frameworks.

Light-induced electron transfer can broaden the substrate range of metalloenzyme. However, the efficiency of photo-enzyme coupling is limited by the poor combination of photosensitizer or photocatalyst with enzyme. Herein, we prepared the nano-photocatalyst MIL-125-NH2@Ru(bpy) by in site embedding ruthenium pyridine-diimine complex [Ru(bpy)3]2+ into metal organic frameworks MIL-125-NH2 and associated it with multicopper oxidase (MCO) laccase. Compared to [Ru(bpy)3]2+, the coupling efficiency of MIL-125-NH2@Ru(bpy)3 for enzymatic oxygen reduction increased by 35.7%. A series of characterizations confirmed that the amino group of laccase formed chemical bonds with the surface defects or hydrophobic groups of MIL-125-NH2@Ru(bpy)3. Consequently, the tight binding accelerated the quenching process and electron transfer between laccase and the immobilized ruthenium pyridine-diimine complex. This work would open an avenue for the synthesis of MOFs photocatalyst towards photo-enzyme coupling.

Boosting the performance of LaCoO3/MoS2 perovskite interface for sustainable decontaminants under visible light-driven photocatalysis.

The novel composite LaCoO3/MoS2 hybrid nanostructure was synthesized via a combination of sol-gel, hydrothermal, and ultrasonication methods. Alizarin Red S (ARS) and Rhodamine B (RhB) were employed as a model pollutant, to assess the photodegradation efficiency of synthesized catalysts. The effect of MoS2 (2.5%, 5%, 7.5%, and 10%) on LaCoO3 (LCO) and its photocatalytic performance was studied. The properties of synthesized catalysts were assessed using various material characterization techniques. The photocatalytic dye degradation of ARS and RhB was investigated under visible light. Among the synthesized catalyst LM-5% composite (LaCoO3 with 5% MoS2) is determined to be the best photocatalyst as it degrades 96 % (ARS) and 90 % (RhB) in 40 min and 80 min, respectively. The photocatalyst is stable even after multiple runs and exhibits negligible loss in degradation efficiency during the cyclic test. Trapping experiments reveal the significance of superoxide anion and hydroxyl radicals against the photodegradation of ARS and RhB. The kinetics of photodegradation of ARS and RhB by LM-5% is found to be 5.70 × 10-2 and 2.25 × 10-2 min-1, respectively. Herein, we demonstrated a catalyst possessing excellent photodegradation activity which may ignite the possibilities of using efficient photocatalysts for environmental remediation.

Visible light-driven C/O-g-C3N4 activating peroxydisulfate to effectively inactivate antibiotic resistant bacteria and inhibit the transformation of antibiotic resistance genes: Insights on the mechanism.

Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) dissemination within water pose a serious threat to public health. Herein, C and O dual-doped g-C3N4 (C/O-g-C3N4) photocatalyst, fabricated via calcination treatment, was utilized to activate peroxydisulfate (PDS) to investigate the disinfection effect on tetracycline-resistant Escherichia coli and the transformation frequency of ARGs. As a result, approximately 7.08 log E. coli were inactivated, and 72.36 % and 53.96 % of antibiotics resistance gene (tetB) and 16 S rRNA were degraded respectively within 80 min. Futhermore, the transformation frequency was reduced to 0.8. Characterization and theoretical results indicated that C and O doping in g-C3N4 might lead to the electronic structure modulation and band gap energy reduction, resulting in the production of more free radicals. The mechanism analysis revealed that C/O-g-C3N4 exhibited a lower adsorption energy and reaction energy barrier for PDS compared to g-C3N4. This was beneficial for the homolysis of O-O bonds, forming SO4•- radicals. The attack of the generated active species led to oxidative stress in cells, resulting in damage to the electron transport chain and inhibition of ATP production. Our findings disclose a valuable insight for inactivating ARB, and provide a prospective strategy for ARGs dissemination in water contamination.