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3D flower-like hierarchical mesoporous Bi4O5I2/MoS2 Z-scheme layered heterojunction photocatalyst was fabricated by oil bath and hydrothermal methods. The heterojunction with narrow band gap of ∼1.95 eV extended the photoresponse to near-infrared region, which showed obvious photothermal effect due to the introduction of MoS2 with broad spectrum response. MoS2 nanosheets were anchored onto the surface of flower-like hierarchical mesoporous Bi4O5I2 nanosheets, thereby forming efficient layered heterojunctions, the solar-driven photocatalytic efficiency in degradation of highly toxic dichlorophenol and reduction of hexavalent chromium was improved to 98.5% and 99.2%, which was ∼4 and 7 times higher than that of the pristine Bi4O5I2, respectively. In addition, the photocatalytic hydrogen production rate reached 496.78 μmol h-1 g-1, which was ∼6 times higher than that of the pristine Bi4O5I2. The excellent photocatalytic performance can be ascribed to the promoted photothermal effect, as well as, the formation of compact Z-scheme layered heterojunctions. The 3D flower-like hierarchical mesoporous structure provided adequate surface active-sites, which was conducive to the mass transfer. Moreover, the high stability of the prepared photocatalyst further promoted its potential practical application. This strategy also provides new insights for fabricating layered Z-scheme heterojunctions photocatalysts with highly photothermal-photocatalytic efficiency.

An analytical solution for contaminant transport through a vertical cut-off wall and aquifer system is developed, which can consider the advection, dispersion and degradation processes. The uniqueness of the solution is that it includes hyperbolic eigenfunctions, considers the degradation process and is suitable for an aquifer with finite thickness due to the existence of a river or lake. The solution is first verified against an existing analytical solution and a numerical model using the Comsol software program. The three important aspects are then investigated and some important conclusions are obtained. In some scenarios, the hyperbolic eigenfunctions must be considered; otherwise, the obtained results are unreasonable. When the aquifer thickness is more than a critical value (approximately ten times the cut-off wall thickness in this study), it is reasonable to regard the aquifer as semi-infinite. Contaminant degradation has significant influence on contaminant transport. A higher degradation intensity leads to a lower contaminant concentration but a larger mass flux in the cut-off wall. Therefore, the present solution is suitable for an aquifer with arbitrary thickness and has better applicability than the existing analytical solutions. It is promising to be used as an applicable tool for the design of vertical slurry cut-off walls.

In this work, Ag/Bi5O7I nanocomposite was prepared and firstly applied in piezo/photocatalytic reduction of N2 to NH3 and methyl orange (MO) degradation. Bi5O7I was synthesized via a hydrothermal-calcination method and shows nanorods morphology. Ag nanoparticles (NPs) were photo deposited on the Bi5O7I nanorods as electron trappers to improve the spatial separation of charge carriers, which was confirmed via XPS, TEM, and electronic chemical analyses. The catalytic test indicates that Bi5O7I presents the piezoelectric-like behavior, while the loading of Ag NPs can strengthen the character. Under ultrasonic vibration, the optimal Ag/Bi5O7I presents high efficiency in MO degradation. The degradation rate is determined to be 0.033 min−1, which is 4.7 folds faster than that of Bi5O7I. The Ag/Bi5O7I also presents a high performance in piezocatalytic N2 fixation. The piezocatalytic NH3 generation rate reaches 65.4 μmol L−1 g−1 h−1 with water as a hole scavenger. The addition of methanol can hasten the piezoelectric catalytic reaction. Interestingly, when ultrasonic vibration and light irradiation simultaneously act on the Ag/Bi5O7I catalyst, higher performance in NH3 generation and MO degradation is observed. However, due to the weak adhesion of Ag NPs, some Ag NPs would fall off from the Bi5O7I surface under long-term ultrasonic vibration, which would greatly reduce the piezoelectric catalytic performance. This result indicates that a strong binding force is required when preparing the piezoelectric composite catalyst. The current work provides new insights for the development of highly efficient catalysts that can use multiple energies.

Photocatalytic oxidation of toxic pollutants is a proficient technique to solve the problems associated with the treatment of bisphenol-A which is classified as 1B reprotoxic substance. In this paper, Ag2C2O4/Ag@GNS nanocomposite whereas Ag and graphene nanosheets (GNS) used as the charge carriers, which is combined through peroxymonosulfate (PMS) for the removal of bisphenol-A (BiP-A) for the first time. The XRD, UV-DRS, SEM, and TEM studies were performed to confirm the phase structure and the purity. Ag2C2O4/Ag@GNS nanocomposite exhibited superior photocatalytic performance and removal rate when compared with pure Ag2C2O4 and pure GNS. In Ag2C2O4/Ag@GNS photocatalyst, the deposited Ag on the surface of Ag2C2O4 rods effectively formed a metal and semiconductor heterostructure, thus photogenerated charge carriers were separated easily by the surface plasmon resonance effect (SPR) effect of noble Ag. Hence charge carriers lifetime has been extended to a great extent for the better photocatalytic performance. The experimental results confirmed that the O2−, OH, SO4− radicals were played major role in the photolysis process. Furthermore, the effect of the photocatalyst & PMS concentration, pH and co-existing ions towards the BiP-A degradation were studied in detail. According to the mass spectroscopy studies BiP-A pollutant was effectively deteriorated into smaller molecules and CO2, H2O. Furthermore, we have proposed the possible degradation pathway and photocatalytic mechanism for better understanding.

Surface water bodies are getting contaminated day by day. Pollutants like 2-Chloropyridine (a class of halogenated pyridine derivative which are widely used in pharmaceutical and agrochemical sector) is detected in surface water bodies. It is toxic and carcinogenic. One of the reason of its presence in water bodies can be attributed to effluents from sewage treatment and industrial waste treatment plants, which may be due to inefficient conventional treatment technologies. Use of Advanced Oxidation technologies like Fenton’s oxidation has proven to be a promising alternative to degrade these recalcitrant and non-biodegradable compounds. The Present study accesses the applicability of laterite soil as a source of iron catalyst in Fenton’s oxidation process to degrade2-chloropyridine (2-CP) at various concentrations. Parameters like pH, dosage of laterite iron, hydrogen peroxide are optimized. Effect of initial concentration of the target compound on degradation kinetics is also investigated. Up to 75% degradation was achieved in a total reaction time period of 10hrs corresponding to Laterite iron: H2O2 ratio of 1:50 at a pH of 3 for a sample containing 2-CP compound at 10 mg/L. Use of iron in Fenton’s oxidation process harnessed from the laterite soil can be a suitable alternative to treat polluted water bodies contaminated with pharmaceutical halopyridine compounds.

Due to various anthropogenic activities, environmental pollution is increasing day by day. Currently human as well as the whole living population is in threat due to Organic pollutants. Several pertaining measures have been done for the reduction of organic pollutants. Various petrochemical activities resulted in the release of organic pollutants into the environment. These organic pollutants are measured as lethal, oncogenic, and unsafe. Hence their reduction is essential for hours with effective and sustainable techniques. Recently, scientists and researchers all over the worldwide are focusing their research activities on these topics due to various emerging environmental problems. Among the several techniques, photocatalytic degradation gained much attention to, the removal of organic pollutants present in the environment. In the present review paper, we had discussed the efficient photocatalytic degradation of organic compounds using various copper-based nanomaterials. We have elaborated in detail about the most efficient copper-based nanoparticles as a photocatalyst used in wastewater treatment for the removal of various organic pollutants. The catalytic activity of copper nanomaterial-based photocatalyst showed high reusable stability, high degradation efficiency up to 99.9% due to their good stability and reusability.

The rapid degradation of magnesium (Mg)-based implants in physiological environment limits its clinical applications, and alloying treatment is an effective way to regulate the degradation rate of Mg-based materials. In the present study, three Mg alloys, including Mg-0.8Ca (denoted as ZQ), Mg-0.8Ca-5Zn-1.5Ag (denoted as ZQ71) and Mg-0.8Ca-5Zn-2.5Ag (denoted as ZQ63), were fabricated by alloying with calcium (Ca), zinc (Zn) and silver (Ag). The results obtained from electrochemical corrosion tests and in vitro degradation evaluation demonstrated that the three Mg alloys exhibited distinct corrosion resistance, and ZQ71 exhibited the lowest degradation rate in vitro among them. After addition of Zn and Ag, the antibacterial potential of Mg alloys was also enhanced. The in vitro cell experiments showed that all the three Mg alloys had good biocompatibility. After implantation in a rat femoral defect, ZQ71 showed significantly higher osteogenic activity and bone substitution rate than ZQ63 and ZQ, due to its higher corrosion resistance as well as the stimulatory effects of the released metallic ions. In addition, the average daily degradation rate of each Mg alloy in vivo was significantly higher than that in vitro, as could be due to the implantation site located in the highly vascularized trabecular region. Importantly, the correlations between the in vitro and in vivo degradation parameters of the Mg alloys were systematically analyzed to find out the potential predictors of the in vivo degradation performance of the materials. The current work not only evaluated the clinical potential of the three biodegradable Mg alloys as bone grafts but also provided a feasible approach for predicting the in vivo degradation behavior of biodegradable materials.

Messenger RNA (mRNA) has emerged as a critical global technology that requires global joint efforts from different entities to develop a COVID-19 vaccine. However, the chemical properties of RNA pose a challenge in utilizing mRNA as a vaccine candidate. For instance, the molecules are prone to degradation, which has a negative impact on the distribution of mRNA among patients. In addition, little is known of the degradation properties of individual RNA bases in a molecule. Therefore, this study aims to investigate whether a hybrid deep learning can predict RNA degradation from RNA sequences. Two deep hybrid neural network models were proposed, namely GCN_GRU and GCN_CNN. The first model is based on graph convolutional neural networks (GCNs) and gated recurrent unit (GRU). The second model is based on GCN and convolutional neural networks (CNNs). Both models were computed over the structural graph of the mRNA molecule. The experimental results showed that GCN_GRU hybrid model outperform GCN_CNN model by a large margin during the test time. Validation of proposed hybrid models is performed by well-known evaluation measures. Among different deep neural networks, GCN_GRU based model achieved best scores on both public and private MCRMSE test scores with 0.22614 and 0.34152, respectively. Finally, GCN_GRU pre-trained model has achieved the highest AuC score of 0.938. Such proven outperformance of GCNs indicates that modeling RNA molecules using graphs is critical in understanding molecule degradation mechanisms, which helps in minimizing the aforementioned issues. To show the importance of the proposed GCN_GRU hybrid model, in silico experiments has been contacted. The in-silico results showed that our model pays local attention when predicting a given position’s reactivity and exhibits interesting behavior on neighboring bases in the sequence.

OBJECTIVES: Empower 3 software is important in modeling, optimization, and reducing the time of manual calculation of related substance by subtracting the baseline of a blank chromatogram from the unknown sample automatically; so, the major objective of the developed method is to introduce a new, selective, and economical high performance liquid chromatography (HPLC) and spectrophotometric method for simultaneous estimation of sodium benzoate (SDB) and cefdinir (CFR) in the presence of its degradation products. MATERIALS AND METHODS: Chromatographic separation is optimized and adjusted using two methods; method (I) is characterized for separation of active pharmaceutical ingredient (CFR) in pure and dosage forms using Atlantis dC18 column [4.6 mm x 250 mm (5 μm particle size or equivalent)] with a mobile phase consisting of methanol: 0.02 M phosphate buffer solution pH 3.0 (40:60 v/v) at a flow rate of 1.0 mL/minute, injection volume 10 μL and wavelength 254 nm. Method (II) is identified for related substances in a Hichrom C18 column (15 x 0.46 cm), 5 μm particle size or equivalent, using a binary gradient consisting of solution A [0.1% tetramethylammonium hydroxide solution (pH: 5.5) with 0.1 M EDTA (1000:0.4 v/v)] and solution B (0.1% tetramethylammonium hydroxide solution (pH 5.5): acetonitrile: methanol : 0.1 M EDTA (500:300:200:0.4 v/v) using injection volume 10 μL for reversed-phase HPLC with a wavelength equals to 254 nm and flow rate 1.0 mL/min. Two ecofriendly spectrophotometric methods were successfully used to resolve the spectral overlap of drugs. RESULTS: Method A, the first derivative of ratio spectra spectrophotometric method (1(st)DD) where CFR was determined at two wavelengths 283.5 nm, 313.4 nm and SDB was determined at 216.7 nm, 235.5 nm. Method B, ratio subtraction method is performed to overcome the interference between CFR and the preservative SDB. The ultraviolet spectrum of the laboratory mixture is divided by that of CFR (20 μg/mL) as a divisor then subtracting the amplitudes in the plateau region at 250-315 nm (the constant) from that of the ratio spectrum. The zero-order spectra of SDB were obtained at 225 nm by multiplying the resulting ratio spectra by the divisor (CFR), zero order of CFR was been estimated at a wavelength value of 283 nm after multiplication of the divisor by the obtained constant. CONCLUSION: The optimized method was adjusted and validated as per International Conference on Harmonization guidelines and could be easily utilized by quality control laboratories and for laboratory-prepared mixtures.

Microbial fuel cell (MFC) is an emerging technology which has been immensely investigated for wastewater treatment along with electricity generation. In the present study, the treatment efficiency of MFC was investigated for hydrocarbon containing wastewater by optimizing various parameters of MFC. Mediator-less MFC (1·2 l) was constructed, and its performance was compared with mediated MFC with Escherichia coli as a biocatalyst. MFC with electrode having biofilm proved to be better compared with MFC inoculated with suspended cells. Analysis of increasing surface area of electrode by increasing their numbers indicated increase in COD reduction from 55 to 75%. Catholyte volume was optimized to be 750 ml. Sodium benzoate (0·721 g l–1) and actual common effluent treatment plant (CETP) wastewater as anolyte produced 0·8 and 0·6 V voltage and 89 and 50% COD reduction, respectively, when a novel consortium of four bacterial strains were used. Twenty MFC systems with the developed consortium when electrically connected in series-parallel connection were able to generate 2·3 V and 0·5 mA current. This is the first report demonstrating the application of CETP wastewater in the MFC system, which shows potential of the system towards degradation of complex organic components present in industrial wastewater.

Low dimensional sp3 carbon nanostructures have attracted increasing attention recently, due to their unique properties and appealing applications. Based on in silico studies, this work exploits the impacts from functional groups on the tensile properties of carbon nanothreads (NTH) – a new sp3 carbon nanostructure. It is found that functional groups will alter the local bond configuration and induce initial stress concentration, which significantly reduces the fracture strain/strength of NTH. Different functional types lead to different local bond re-configurations, and introduce different impacts on NTH. Further studies reveal that the tensile properties decreases generally when the content of functional groups increases. However, some NTHs with higher content of functional groups exhibit higher fracture strain/strength than their counterparts with lower percentage. Such observations are attributed to the synergetic effects from the sample length, self-oscillation, and distribution of functional groups. Simulations show that the tensile behaviour of NTH with the same functional percentage differs when the distribution pattern varies. Overall, ethyl groups are found to induce larger degradation on the tensile properties of NTH than methyl and phenyl groups. This study provides a comprehensive understanding of the influence from functional groups, which should be beneficial to the engineering applications of NTH.

Ultra-performance liquid chromatographic (UPLC) method, for ledipasvir and sofosbuvir determination in bulk mixtures, and in tablets was developed and validated. The determination of the drugs, ledipasvir and sofosbuvir was carried out applying BEH C18 column (50 mm × 2.1 mm i.d, 1.6 µm particle size), with UV detector at λ max of 220 nm. The mobile phase applied for the current study, composed of two solvents, A (0.01 N w/v potassium di-hydrogen orthophosphate buffer of pH 3.5 modified with dilute orthophosphoric acid) and B (acetonitrile) in the ratio of 50:50 v/v. The isocratic mobile phase was moved at a flow rate of 0.3 ml/min. The validation study with proportionate to selectivity, linearity, robustness, precision, accuracy, stability, (LOD) limit of detection and (LOQ) limit of quantification, was performed utilizing the ICH Guidelines. Ledipasvir and Sofosbuvir displaying a linear response between 22.5-135 μg/ml for Ledipasvir 100-600 µg/ml for Sofosbuvir, with correlation coefficient (R2) 0.9997 and 0.998 for Ledipasvir and Sofosbuvir respectively. The % recovery for Ledipasvir and Sofosbuvir was 99.72 ± 0.61% and 100.21 ± 0.68 respectively. The LOD and LOQ values for Ledipasvir and Sofosbuvir were obtained to be 0.31 and 0.95 µg/ml and 1.29 and 3.91 µg/ml, respectively. The method also exhibits good robustness for different chromatographic conditions like mobile phase, temperature and flow rate. So, the approach can be successfully implemented for the quantitative analysis of ledipasvir and sofosbuvir in the (Q.C) Quality Control of in-house developed tablets, and the same can be exercised for the industrial use.

Photocatalytic optical fibers are promising for the degradation of gaseous and volatile pollutants in air due to their high specific surface area, high light utilization efficiency, easy regeneration, and sustainability. In particular, photocatalytic optical fibers have proven highly useful for the removal and conversion of different kinds of air pollutants in air. However, these fibers suffer from low photocatalytic degradation efficiencies. In this review, we have focused on introducing photocatalytic quartz optical fibers and photocatalytic plastic optical fibers for the degradation and transformation of gas-phase air pollutants. The principle of photocatalytic optical fibers and main methods for improving their photocatalytic and light utilization efficiencies based on semiconductor photocatalytic coatings are summarized. Moreover, the Langmuir-Hinshelwood kinetic rate equation was summarized to analyze the photocatalytic reduction of gaseous pollutants. Finally, an outlook on the future of photocatalytic optical fibers toward the removal and conversion of gaseous air pollutants is discussed.

Introduction: Cannabidiol (CBD), cannabinol (CBN), and Δ9-tetrahydrocannabinol (Δ9-THC) are major cannabinoids in cannabis resin and products. The kinetic of the chemical reaction of resin cannabis is important for product development and storage. A few reports are available in the literature on the rate of CBD and Δ9-THC degradation, and CBN formation in dried resin and solutions of various pH. Materials and Methods: Thermal degradation of CBD, Δ9-THC, and formation of CBN was studied at 50°C, 60°C, 70°C, and 80°C for dried cannabis resin. The effect of pH and temperature on cannabinoids transformation in cannabis solution was also examined at pH 2, 4, 6, 8, 10, and 12 and at 40°C, 50°C, 60°C, and 70°C. High-performance chromatography coupled with diode-array detection (HPLC-DAD) was used for the analysis of CBD, CBN, and Δ9-THC transformation. The values of activation energies (Ea), shelf-life (t90% - t110%), and rate constant (k) were calculated for the CBD, Δ9-THC, and CBN. The effect of temperature and pH on the dried cannabis resin was adequately modeled with the Arrhenius equation. Results: The results indicated that the chemical kinetics in the thermal degradation of CBD, Δ9-THC, and formation of CBN were the zero-order, pseudo-zero-order, and first-order reactions, respectively, in cannabis resin. The first-order and pseudo-first-order degradation kinetics were evidenced for CBD and Δ9-THC, respectively, in cannabis solutions, whereas the zero-order formation kinetic was detected for the CBN. The transformation rate of the CBD, CBN, and Δ9-THC increased with increasing temperature, especially as temperature increased to 70°C at pH 2.0. The optimum pH for CBD stability was between pH 4 and 6, whereas the optimum pH for Δ9-THC stability was between pH 4 and 12. Conclusion: The major cannabinoids (CBD, CBN, and Δ9-THC) reacted more quickly at high temperature and in an acidic solution. Especially, the minimum transformation of CBD, CBN, and Δ9-THC was achieved by using on a low temperature, slightly to moderately acidic pH values, and short-time processing. These results may help to improve the storage condition of CBD, CBN, and Δ9-THC products and in the manufacturing process.

Plastic films play an important role in China's agricultural production. However, the large-scale use of plastic film has also caused very serious agricultural film pollution. Biodegradable polymers have received much attention because of the environmental pollution caused by the traditional plastic mulching film. The most typical copolymer is poly (butylene adipate co butylene terephthalate) (PBAT). Poly (Butylene Adipate-co-Terephthalate) (PBAT) is a kind of aliphaticaromatic polyester with excellent biodegradability and mechanical processing properties. Therefore, it has been rapidly developed and widely used in the industry. However, the degradation period of the agricultural film depends on certain requirements. Currently, the degradable materials available in the market do not meet the needs of all crops due to their degradation period. In this paper, the basic properties, degradation process and methods to delay the degradation of PBAT are reviewed for improving the degradation period of the plastic film that is prepared by using this kind of material. The degradation process includes photodegradation, biodegradation, and hydrolysis. The methods of delaying the degradation process include adding a chain extender, light stabilizer, antihydrolysis agent and antibacterial agent, providing a theoretical basis for the research and development of biodegradable film with a controllable degradation cycle. The future research and development of biodegradable polymers will mainly focus on controllable degradation rate, stable degradation cycle, new materials, and reducing research and development costs.

Global warming has led to increasing pile foundation deterioration in permafrost regions. Theoretical analysis and indoor model tests were used to analyse variations in the shaft resistance and ultimate bearing capacity (UBC) for various permafrost active-layer thicknesses (Za). A relationship for atmospheric temperature, Za and ground temperature was developed. The equivalent adfreezing force was used as an index to evaluate the degradation of pile foundation bearing behaviour and a theoretical model was established. Based on the theoretical degradation model and indoor experimental data, a model was established to reflect the deterioration of pile foundation bearing behaviour in warm permafrost regions. The model was verified using numerical simulations. The results showed that shaft resistance at the ultimate state can be divided into three stages (stable change, rapid increase and attenuation). The depth of the maximum values decreased from −0.40 m to −0.65 m with an increase in Za. The pile head load (Q) against pile head settlement (S) curves were divided into three stages (elastic stage, elastic–plastic and plastic). A greater Za made the plastic stage of the Q–S relationship occur earlier, resulting in a gradual decrease in UBC. The degradation variable (D) of bearing behaviour showed rapidly and then slowly increasing deterioration. This study provides experimental support for clarifying the degradation mechanism of pile foundation bearing behaviour and a degradation model to consider and quantify the impact of climate change on pile foundations in degraded permafrost.

In this study, biochar (BC) derived from pomelo was prepared via a high-temperature calcination method to modify the graphitic carbon nitride (g-C3N4) to synthesize the BC/g-C3N4 composite for the degradation of the tetracycline (TC) antibiotic under visible light irradiation. The experimental results exhibit that the optimal feeding weight ratio of biochar/urea is 0.03:1 in BC/g-C3N4 composite could show the best photocatalytic activity with the degradation rate of tetracycline is 83% in 100 min irradiation. The improvement of photocatalytic activity is mainly attributed to the following two points: (i) the strong bonding with π-π stacking between BC and g-C3N4 make the photogenerated electrons of light-excited g-C3N4 transfer to BC, quickly and improve the separation efficiency of carriers; (ii) the introduction of BC reduces the distance for photogenerated electrons to migrate to the surface and increases the specific surface area for providing more active sites. This study provides a sustainable, economical and promising method for the synthesis of photocatalytic materials their application to wastewater treatment.

CeO2/g-C3N4 photocatalysts have attracted tremendous attention in the photocatalytic degradation of organic pollutants. The design and construction of highly active CeO2/g-C3N4 photocatalysts without harsh conditions is still challenged. Herein, highly dispersed CeO2–x nanoparticles with rich oxygen vacancies were successfully precipitated on the surface of g-C3N4 under mild conditions. The fabricated CeO2–x/g-C3N4 exhibits remarkable activity and stability for photocatalytic degradation of MO pollutant. The optimal rate constant of MO degradation over CeO2–x/g-C3N4 is about 0.031 min–1, which is three times higher than that of g-C3N4. A negligible activity decrease is observed after three cycling runs. The enhanced catalytic performance can be ascribed to the excellent dispersion of CeO2–x with rich oxygen vacancies that benefit O2 adsorption and visible light absorption. In addition, the proper band alignment between CeO2–x and g-C3N4 is conducive to the highly efficient separation of photogenerated electron-hole pairs.

The natural hematite (α-Fe2O3) is stable and abundant on the earth, as well as with strange electronic band structure and good visible light absorption properties. However, the composition and catalytic performance of natural hematite should be explored. In this study, the photo-assisted hematite nanoparticles activated persulfate (H-NPs/PS/vis) system was constructed. As detected, H-NPs had an irregular agglomerate structure with abundant internal pore and were mainly composed of Fe2O3, SiO2 and TiO2. The system was applied to removing various antibiotic (i.e., lomefloxacin, ciprofloxacin and enrofloxacin with initial concentration of 10 mg/L), achieving high degradation performance of 82.0%, 81.2% and 82.2% after 120, 330 and 240 min, respectively. Moreover, H-NPs had excellent reusability with low metal leaching (Ti leaching percentage lower than 0.01%, Fe dissolution percentage was 0.48%) and stable structure. At last, a possible reaction mechanism of H-NPs/PS/vis system was proposed that lomefloxacin (LOM) was efficiently removed via the synergistic process of components contained in H-NPs with PS and light, involving the generation of •O2−, •OH and SO4•−. Above all, this paper provided a novel application scheme of natural hematite through in-depth and comprehensive experimental exploration.

Abstrct Polycaprolactone/hydroxyapatite (PCL/HA) composite coating was fabricated by a combination of hydrothermal and dipping methods to delay the degradation of Mg alloy AZ31 as bioresorbable materials. The PCL/HA coating was composed of nano rod-shape HA crystals and PCL filled in the space of HA crystals. Compared with the single HA coating, the binding strength between the PCL/HA composite coating and Mg alloy was obviously improved and the PCL/HA coating still adhered to the surface of AZ31 substrate even after 38 days of immersion. The electrochemical corrosion rate of HA coated sample was reduced by ten times after being filled by PCL. The electrochemical impedance spectroscopy (EIS) and immersion test results showed that the PCL/HA composite coating could provide a more effective barrier for Mg substrate than the HA coating alone. The cytocompatibility and the antibacterial property of HA coating and PCL/HA coating were evaluated by culturing with bone marrow-derived mesenchymal stem cells (BMSCs) and methicillin-resistant staphylococcus aureus (MRSA) for 24 h under direct culture conditions, respectively. The PCL/HA composite coating showed better BMSC cell compatibility, more suitable for BMSC adhesion than HA coating alone and showed a potential application prospect as a biological materials. However, from the perspective of clinical applications, the antibacterial property of PCL/HA composite coating needs to be further improved.

In this study, β-blocker metoprolol was degraded by photocatalysis and photo-Fenton catalyzed by doped TiO2. The effect of two main variables was elucidated, content and type of doping cation (Fe or Cu). The catalysts were synthesized by Evaporation-Induced Self-Assembly (EISA) method and their performance was compared with typical Degussa P25. All synthesized materials were found to be mesoporous with a specific surface in the range of 121–242 m2/g, they all exhibited anatase phase, and crystallites in the range of 6–10 nm. The use of X-ray photoelectron spectroscopy (XPS) allowed to establish not only the presence of the expected Ti4+ but also Ti3+ species. Cu2+ and Fe3+ species were also identified in the doped catalysts. It was found that the addition of Cu and Fe diminished the energy band gap of synthesized TiO2, from 3.20 eV to 2.58 and 2.64, respectively. The content of Cu is directly correlated with this effect. In photocatalysis, the doping of TiO2 did not have an effect of metoprolol degradation rate. This was improved, however, approximately 60% by the synthesized TiO2 compared to Degussa P25. On the other hand, the photo-Fenton-like process catalyzed by Cu-TiO2 exhibited the highest degradation (total removal) and mineralization extent (90%), being faster than the photocatalytic process and the UV-H2O2 system. Another difference between both methods, was the amount and type of intermediates generated. These were identified by LC-MS. Photo-Fenton catalyzed by Cu/TiO2 can be considered as an effective process with high oxidative power in the metoprolol degradation.

Bioactive materials XX, S2452199X21005077 (2021). doi:10.1016/j.bioactmat.2021.10.041, Biodegradable magnesium (Mg) alloys can revolutionize osteosynthesis, because they have mechanical properties similar to those of the bone, and degrade over time, avoiding the need of removal surgery. However, they are not yet routinely applied because their degradation behavior is not fully understood.In this study we have investigated and quantified the degradation and osseointegration behavior of two biodegradable Mg alloys based on gadolinium (Gd) at high resolution.Mg-5Gd and Mg-10Gd screws were inserted in rat tibia for 4, 8 and 12 weeks. Afterward, the degradation rate and degradation homogeneity, as well as bone-to-implant interface, were studied with synchrotron radiation micro computed tomography and histology. Titanium (Ti) and polyether ether ketone (PEEK) were used as controls material to evaluate osseointegration.Our results showed that Mg-5Gd degraded faster and less homogeneously than Mg-10Gd. Both alloys gradually form a stable degradation layer at the interface and were surrounded by new bone tissue. The results were correlated to in vitro data obtained from the same material and shape. The average bone-to-implant contact of the Mg-xGd implants was comparable to that of Ti and higher than for PEEK. The results suggest that both Mg-xGd alloys are suitable as materials for bone implants., Published by Elsevier B.V., [Amsterdam]

In this work, different types of photocatalysts in single (CdS and CeO2) and binary (CdS/CeO2 in different molar ratio: 0.5:1, 1:1 and 1:0.5) systems were synthesized by co-precipitation method. Crystal structure, surface area, morphology, band gap energy, functional groups and optical properties of the as-synthesized photocatalysts were characterized by using XRD, BET, SEM-EDX, UV/Vis, FTIR and PL instruments, respectively. Photocatalytic activities of single and binary nanocomposite were evaluated by using aqueous solution of model pollutant methyl orange dye (MeO). Photocatalytic activities of binary CdS/CeO2 (1:1) nanocomposite were found to be higher than those of single counterparts. The photodegradation efficiencies of the binary system were found to be 53.73%. The reusability of binary photocatalyst was tested and only about 33% decrement was observed after four successive runs. Photocatalytic degradation of MeO dye follows the pseudo first order kinetics for the entire as-synthesized nanocomposite. The results also suggest that in the CdS/CeO2 (1:1) nanocomposite the photoinduced electrons and holes can be effectively separated.

Purpose It is challenging to treat and manage gentamicin mycelial residue (GMR) due to the high residual antibiotic content in GMR. The objective of this study is aimed to investigate the viability of recycling GMR by co-composting with rice chaff, describe the dynamics of the physicochemical and biology parameters and microbial community, and evaluate the maturity of the compost products. Methods The co-composting process applied was a pilot-scale composting process under the conditions found outside the laboratory. Three 1-tonne piles of fresh GMR were composted in each treatment; test treatment contained rich chaff and the control did not. Dried GMR was made by drying fresh GMR. Three compost treatments were as follows: (1) no rice chaff, 8:1 weight/weight fresh GMR-to-dried GMR (CK); (2) 8:1 weight/weight fresh GMR-to-rice chaff (T1); and (3) 4:1 weight/weight fresh GMR-to-rice chaff (T2). The raw materials were made into three compost cones of 2 m diameter and 1.5 m height.Results The optimal fresh GMR:rice chaff ratio (w/w) was 4:1. Over 99% of gentamicin was degraded after 73 days of co-composting. The key parameters of the final products, such as the pH, C/N ratio, germination index and crop growth indexes, all met the national standards for compost maturity indicators. Compared with those of fungi, the abundance and diversity of bacteria obviously increased during co-composting. Canonical correlation analysis (CCA) revealed that the bacterial community dynamics were closely correlated with the amount of residual gentamicin. Micromonospora and Enterococcus may have been the key microorganisms degrading the gentamicin.Conclusion The addition of rice chaff improved the decomposition of gentamicin residue in the GMR and made the GMR usable in fertilizer; this result could help antibiotic production factories recycle more of their waste products. The results provide new insight into the potential for co-composting with rice chaff to achieve sustainable GMR management.

Peracetic acid (PAA)-based system is becoming an emerging advanced oxidation process (AOP) for effective removal of organic contaminants from water. Various approaches have been tested to activate PAA, while no previous researches reported the application of metal-organic frameworks (MOFs) materials for PAA activation. In this study, zeolitic imidazole framework (ZIF)-67, a representative MOFs, was facile synthesized via direct-mixing method at room temperature, and tested for PAA activation and sulfachloropyridazine (SCP) degradation. The as-synthesized ZIF-67 exhibited excellent performance of PAA activation and SCP degradation with 100% of SCP degraded within 3 min, owing to the specific MOFs structure and abundant Co2+ sites. The pseudo-first-order kinetic model was applied to fit the kinetic data, with rate constant k1 of ZIF-67 activated PAA system 34.2 and 156.5 times higher than those of conventional Co3O4 activated PAA and direct oxidation by PAA. Radical quenching experiments and electron paramagnetic resonance (EPR) analysis indicated that CH3C(O)OO• played a major role in this PAA activation system. Then, the Fukui index based on density functional theory (DFT) calculation was used to predict the possible reaction sites of SCP for electrophilic attack by CH3C(O)OO•. In addition, the degradation pathway of SCP was proposed based on Fukui index values and intermediates detection, which mainly included the S-N bond cleavage and SO2 extrusion and followed by further oxidation, dechlorination, and hydroxylation. Therefore, ZIF-67 activated PAA is a novel strategy and holds strong potential for the removal of emerging organic contaminants (EOCs) from water.

Bismuth-rich Bi5O7Br is a promising photocatalyst for pollutant removal owing to its stability and appropriate band structure in comparison with bismuth oxybromide. However, bulk-phase Bi5O7Br suffers from poor light absorption and high charge recombination rates resulting in poor activity. Elemental doping is a powerful strategy to enhance photocatalytic activity. In this study, we prepared a series of Br auto-doped ultrathin Bi5O7Br nanotubes and explored the effect of Br doping on photocatalytic NO removal. The optimal doping content was determined via a photocatalytic NO removal experiment, which revealed the optimal ratio of Bi and Br was approximately 3:1. In situ diffuse reflectance infrared Fourier transform spectroscopy (In situ DRIFT) and density functional theory (DFT) studies revealed that NO removal mechanism catalyzed by Br doped Bi5O7Br. Our work presents a new strategy for the enhancement of photocatalytic pollutant degradation by bismuth oxyhalide photocatalysts.

N-doped reduced graphene oxide quantum dots (N-rGQDs) have attracted more and more attention in efficient catalytic degradation of aqueous organic pollutants. However, the synthesis of N-rGQDs is generally a complex and high energy required process for the reduction and N-doping steps. In this study, a facile and green fabrication approach of N-rGQDs is established, based on a metal-free Fenton reaction without additional energy-input. The N structures of N-rGQDs play a significant role in the promotion of their catalytic performance. The N-rGQDs with relatively high percentage of aromatic nitrogen (NAr-rGQDs) perform excellent catalytic activities, with which the degradation efficiency of pollutant is enhanced by 25 times. Density functional theory (DFT) calculation also indicates aromatic nitrogen structures with electron-rich sites are prone to transfer electron, presenting a key role in the catalytic reaction. This metal-free Fenton process provides a green and cost-effective strategy for one-step fabrication of N-rGQDs with controllable features and potential environmental catalytic applications.

Composites of Titanium (IV) oxide combined with montmorillonite (MMT) with various TiO2/MMT were prepared for photocatalysis application. The prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and diffuse reflectance UV–visible spectroscopy. The main influential factors such as the TiO2/MMT dose, calcined temperature and pH value of the solution were studied. The main intermediates of phenol degradation were determined by High Performance Liquid Chromatography (HPLC). The results showed that the average size of TiO2 nanoparticles was decreased from 22.51 nm to 10.66 nm through the immobilization on MMT. The components in the interlayer domain were replaced by titanium pillars, and the pillaring reaction proceeded in the interlayer domain, and the basic skeleton of MMT was unchanged, and also TiO2 was dispersed on the surface of the MMT. When the initial concentration of phenol is 10 mg/L, the phenol solution pH is 6 and the UV light irradiation time is 240 min, the phenol degradation rate of 30%TiO2/MMT composite is 89.8%, which is better than MMT (11.5%) and pure TiO2 (58.8%). It shows that TiO2 loaded on MMT improves its photocatalytic activity. The phenol reaction process detected by HPLC showed that it had undergone through hydroquinone and benzoquinone, and finally converted into maleic acid and carbon dioxide and small molecules. The possible photocatalysis mechanism is presented.

Microfluidics is characterized by the manipulation of fluids in submillimeter channels and has great application potential in encapsulation. To further extend the application of microfluidics in food industries, a 3D printed microfluidic device is used to encapsulate vitamin A and improve its stability. Two natural macromolecules, sodium alginate and gelatin, are added to water as the continuous phase to generate monodisperse emulsion. Under different flow rate ratios, the diameter of droplets decreases with the increase of continuous flow rate. However, at the same flow rate ratio, varying the dispersed and continuous flow rates does not significantly change the diameter and size distribution of emulsion collected. The prepared O/W (oil/water) single emulsion can form microgel particles and avoid degradation of vitamin A by simulated gastric acid; the encapsulated vitamin A will not be released until particles reach simulated intestinal tract. In the simulated digestion in vitro, no vitamin A is released for 2 h in the acidic environment; under an alkaline or neutral environment such as those in intestinal fluids, vitamin A can be released from the microgel particles within 2.5 h. Using the presented approach, emulsions encapsulating vitamin A have been prepared and can potentially be applied to encapsulate other oil-soluble substances in the food industry.

OBJETIVES: To assess the effect of various factors on laser fiber tip degradation with the Thulium Fiber Laser (Tm-fiber): fiber stripping, adjustable laser settings (energy, frequency, peak power)...

Due to the massive discharge of antibiotics in water, it is an urgent matter to remove antibiotics from waste water. The photocatalysts with high stability and activity have attracted extensive attention from researchers. By an in-situ polymerization method, polypyrrole (PPy) was modified on the surface of TiO2 (named as TiO2/PPy). By one-step reduction method, NiCoP was grafted on the surface of TiO2/PPy (named as TiO2/PPy/NiCoP) to synthesize the photocatalyst of TiO2/PPy/NiCoP for degradation of tetracycline (TC) antibiotic. The characterization results revealed that NiCoP was deposited on the surface of TiO2/PPy successfully. The photocatalytic experiment results illustrated that 83.2% of TC could be degraded at natural pH with 20 mg of TiO2/PPy/NiCoP in 50 mL of TC solution (10 mg/L) under visible light irradiation. The high catalytic activity is attributed to the attachment of NiCoP on the surface of TiO2/PPy which can enlarge the light response range of TiO2 effectively. Scavenger studies revealed that the degradation of TC was dominated by •O2− and h+. The photodegradation efficiency of TC with TiO2/PPy/NiCoP still reached over 74% after 5 consecutive cycles, indicating the potential applications in practical wastewater.

Donor-acceptor (D-A) conjugated polymers are widely used in photovoltaic applications and heterogeneous catalysis due to their tunable building block and pre-designable structures. Here, a series of adjustable Donor-acceptor (D-A) benzothiodiazole-based conjugated polymers were designed and synthesized. The photocatalytic performance could be improved by fine-tuning the chemical structure by halogen substitution (F or Cl). The polymers exhibited excellent optoelectronic properties and were effective photocatalysts for the degradation of RhB and MO dyes, as well as promoting the oxidative coupling of benzylamines. Complete degradation of RhB and MO occurred in 30 min under visible light radiation, while the yield of benzylamine coupling mediated by superoxide anion was as high as 82%. Systematic characterization methods were used to gain insights on the unique photocatalytic performance of the polymers. Our findings provide further insights into the design and synthesis of benzothiadiazole-based conjugated polymers as promising organic photocatalysts for solar energy conversion.

Volatile organic compound (VOC) pollution has a serious impact on human and urgently needs to be controlled through the development of new methods and catalytic materials. Compared with traditional thermal catalytic oxidation, the synergistic photothermocatalysis is regarded as a green and environmentally friendly strategy for organic compound pollutant removal, which can promote spontaneous heating of the surface of catalysts to achieve thermal catalytic reaction conditions via harvesting light irradiation. In this paper, a monolithic photothermocatalyst was synthesized through coating graphene oxide (GO) and MnOx in turn on a commercially available melamine sponge, where the GO mainly acted as a photothermal conversion layer to heat the catalytically active MnOx. This monolithic catalyst presented excellent photo-induced activity for formaldehyde elimination under ambient conditions (∼ 90% degradation ratio in 20 min for ∼160 ppm initial concentration formaldehyde), and meanwhile possessed a high catalytic durability for multiple cycles. The kinetic study demonstrated that this photothermocatalytic process followed a pseudo-second-order kinetics. Finally, we proposed a possible formaldehyde degradation pathway based on in situ DRIFTS examination.

Catalytic potential of carbon nanomaterials in peroxydisulfate (PDS) advanced oxidation systems for degradation of antibiotics remains poorly understood. This study revealed ordered mesoporous carbon (type CMK) acted as a superior catalyst for heterogeneous degradation of sulfadiazine (SDZ) in PDS system, with a first-order reaction kinetic constant (k) and total organic carbon (TOC) mineralization efficiency of 0.06 min‒1 and 59.67% ± 3.4% within 60 min, respectively. CMK catalyzed PDS system exhibited high degradation efficiencies of five other sulfonamides and three other types of antibiotics, verifying the broad-degradation capacity of antibiotics. Under neutral pH conditions, the optimal catalytic parameters were an initial SDZ concentration of 44.0 mg/L, CMK dosage of 0.07 g/L, and PDS dosage of 5.44 mmol/L, respectively. X-ray photoelectron spectroscopy and Raman spectrum analysis confirmed that the defect structure at edge of CMK and oxygen-containing functional groups on surface of CMK were major active sites, contributing to the high catalytic activity. Free radical quenching analysis revealed that both SO4•− and •OH were generated and participated in catalytic reaction. In addition, direct electron transfer by CMK to activate PDS also occurred, further promoting catalytic performance. Configuration of SDZ molecule was optimized using density functional theory, and the possible reaction sites in SDZ molecule were calculated using Fukui function. Combining ultra-high-performance liquid chromatography (UPLC)–mass spectrometry (MS)/MS analysis, three potential degradation pathways were proposed, including the direct removal of SO2 molecules, the 14S-17N fracture, and the 19C-20N and 19C-27N cleavage of the SDZ molecule. The study demonstrated that ordered mesoporous carbon could work as a feasible catalytic material for PDS advanced oxidation during removal of antibiotics from wastewater.

A series of transition metals (Fe, Co, Ni, Cu, Cr and Mn)-doped CeO2-TiO2 catalysts were prepared by the sol-gel method and applied for the catalytic removal of 1,2-dichloroethane (DCE) as a model for chlorinated VOCs (CVOCs). The various characterization methods (XRD, N2 adsorption-desorption, UV-Raman, NH3-TPD and H2-TPR) were utilized to investigate the physicochemical properties of the catalysts. The results show that doping Fe, Co, Ni or Mn can obviously promote the activity of CeO2-TiO2 mixed oxides for DCE degradation, which is related to their improved texture properties, acid sites (especially for strong acidity) and low-temperature reducibility. Particularly, CeTi-Fe doped with moderate Fe exhibits excellent activity for DCE degradation, giving a T90% value as low as 250 °C. More importantly, only trace chlorinated byproducts were produced during the low-temperature degradation of various CVOCs (DCM, TCE, CB) over CeTi-Fe1/9 catalyst with high durability.

In this study, a novel continuous flow-circulation photocatalytic reactor was acquired for treatment of synthetic wastewater containing a binary mixture of ammonia and phenol. Performance of the photo-reactor was examined using synthesized N-Doped ZnO Beads (N-ZnB) within the existence of Hydrogen peroxide (H2O2) and UV irradiation. The Beads of catalyst were synthesized using modified sol–gel method. A protocol was followed for the characterization of N-ZnB catalyst by performing some common analytical methods such as SEM, EDS, Raman and DRS. N-Doping narrows in band gap energy as calculated from DRS the band gab energy reduced from 3.2 eV to 3.16 eV and reduces electron – hole pair recombination and accordingly improves the efficiency of ammonia and phenol photo-degradation. The optimum photo-degradation conditions were detected by examining the effect of operational parameters as the flow rate, pH, catalyst dosage, H2O2 concentration and initial concentration for both ammonia and phenol. At optimum conditions, N-ZnB catalyst achieved 98.3% and 95.8% degradation for both ammonia and phenol, respectively, after 2 hr of UV irradiation. Also, the reusing ability and strength of N-ZnB was investigated. The developed beads could be used as an effective catalyst for the degradation of binary mixture of ammonia and phenol from wastewater.

Embedded pellets obtained by means of embedding activated sludge in polyvinyl alcohol—sodium alginate were successfully adapted in aniline wastewater degradation system. The results of shake flask ...

Post-depositional degradation of organic matter (OM) in freshwater sediments is crucial for driving the biogeochemical dynamics and influencing the consequential carbon burial. This process also often causes diagenetic alterations on paleoenvironmental proxies. Yet, mechanisms behind the degradation of sedimentary OM and the depth-related variations in stable isotope ratios can only be explained in part. Degradation of sedimentary OM in two drinking water reservoirs with contrasting trophic states (eutrophic versus mesotrophic) and catchment land-use (agriculture versus forestry) were studied with a combination of typical chemical treatments to group sedimentary organic matter into four different biochemical fractions, i.e., carbohydrates, proteins, lignins and lipids. Our results show that the degradation of sedimentary OM was mainly driven by preferential degradation of aquatic proteins and carbohydrates. In a subsequent step, lipids seemed to be degraded. This process entails more pronounced reduction of sedimentary OM and associated depth variations in δ13C and δ15N in the eutrophic reservoir of agricultural catchment, when compared to the mesotrophic reservoir with a forest dominated catchment. Moreover, changes in the relative proportions of biochemical components in sedimentary OM have more pronounced impact on δ15N isotope values relative to the ones of δ13C. Our findings also suggest that algae-derived OM is primarily responsible for the post-depositional alterations of elemental and isotopic compositions of sedimentary OM. This may be of importance for estimates of carbon sinks in lakes and reservoirs.

Adding gentamicin to silk fibroin enhances both the antibacterial performance and degradation rate of silk-based materials. The increased material degradation rate can affect the strength of early internal fixation, resulting in internal fixation failure. This study sought to adjust the gentamicin concentration to control the material degradation rate, thereby better meeting clinical application requirements. The in vitro degradation, water absorption rate, and expansion rate of silk-based materials containing different gentamicin concentrations were studied. A gentamicin-loaded silk-based screw was implanted into the femurs of New Zealand rabbits. Micro-computed tomography was used to measure the screw diameter, which was then used to calculate the degradation rate. The specimens were stained with hematoxylin and eosin and Masson’s trichrome. The in vitro results revealed increasing material degradation rates with increasing gentamicin concentration but no significant differences in water absorption rates with different gentamicin concentrations. The degradation rates of gentamicin-loaded (4 mg/g) silk-based rod-like materials were approximately 11.08% at three months in vitro and 9.4% in the animal experiment. The time for complete degradation was predicted from the fitting curve to be approximately 16 months. No inflammatory hyperplasia was observed in bone or soft tissue. The degradation and biocompatibility of the material containing 4 mg/g gentamicin meet clinical application requirements, and previous experimental results demonstrate good antibacterial performance of materials containing this gentamicin concentration.

Nanocomposite thin film material Ag(NP)/TiO2(T) was synthesized and fabricated by facile template method and employed for the removal of Alizarin Yellow using UV-A radiations. The materials were suitably characterized by advanced analytical methods. The mechanism and kinetics of dye degradation was extensively studied for various parametric studies. The increase in pH from 6.0 to 8.0 had caused to decrease the removal efficiency of Alizarin Yellow from 53.1 to 37.5 % using the Ag(NP)/TiO2(T) thin film catalyst. The degradation of Alizarin Yellow using the thin film catalyst has followed the pseudo-first order degradation kinetics and the increase in concentration of Alizarin (0.5–15.0 mg/L) has caused to significant decrease in rate constants of degradation. The NPOC results showed significant amount of dye was mineralized since at pH 6.0 the percentage removal of Alizarin Yellow was found to be 48.36 % using the nanocomposite Ag(NP)/TiO2(T) photocatalyst. Photostability of catalyst was reaffirmed by successive photocatalytic operations and at the end of six successive operations has caused to a minimal decrease in percentage removal of Alizarin Yellow i.e., 0.97 % using the thin film catalyst. The co-existence of cations/anions demonstrated the study of real matrix treatment of waste water contaminated with Alizarin Yellow. The scavenger study implied to propose a plausible mechanism of oxidation.

The organic compounds contaminated soil substantially threatens the growth of plants and food safety. In this study, we synthesis zero-valent bimetallic Fe/Cu catalysts for the degradation of 2,4-dichlorophenol (DCP) in soils with persulfate (PS) in combination of organic surfactants and exploring the main environmental impact factors. The kinetic experiments show that the wt5% dosage of Fe/Cu exhibits a higher degradation efficiency (86%) of DCP in soils, and the degradation efficiency of DCP increases with the increase of the initial PS concentration. Acidic conditions are favorable for the DCP degradation in soils. More importantly, the addition of Tween-80, and Triton-100 can obviously desorb DCP from the soil surface, which enhances the degradation efficiency of DCP in soils by Fe/Cu and PS reaction system. Furthermore, the Quenching experiments demonstrate that SO 4 ·- and ·OH are the predominant radicals for the degradation of DCP during the Fe/Cu and PS reaction system as well as non-radical also exist. The findings of this work provide an effective method for remediating DCP from soils. © 2020 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd.. All rights reserved.

This paper presents a comparison between the performances of two chemistries of synthetic oil lubricants, polyalphaolefins (PAOs) and perfluoropolyethers (PFPEs) when applied on gold-plated electrical contacts operating at contact loads of 9.8 cN and experiencing fretting-induced degradation. Performance assessment was done using the contact resistance and coefficient of friction behavior and the surface’s response to fretting in the presence of different types of lubricants within the two chemistries. It was found that the PAOs improved the fretting performance of the lightly loaded contacts, and statistically, were at least fifty times more reliable for a longer duration of fretting cycles than the PFPEs, suggesting their suitability for low contact load applications. At low loads, PFPEs underwent contact separation due to hydrodynamic lubrication, and the behavior was more observable among the PFPEs having higher kinematic viscosities. On the contrary, viscous PAOs had improved fretting performance and delayed time to contact failure than less viscous PAOs. The applied lubricant film thickness also contributed to the contact’s performance, and it was found that increasing the thickness of the PFPE films advanced contact failures, while the PAO film postponed contact’s time to failure.

Photocatalytic technology can solve various environmental pollution problems, especially antibiotic pollution. A novel La-doped MIL-53(Al)/ZnO composite material was successfully synthesized by a combination of hydrothermal method and calcination, showing high photocatalytic degradation percent of sulfamethazine (SMT). The 2 mol% La MIL-53(Al)/ZnO photocatalyst shows the highest degradation efficiency toward SMT (92%) within 120 min, which is 4.1 times higher than pure ZnO (increased from 18% to 92%). In addition, the degradation analysis of SMT by high performance liquid chromatography proves that the products are CO2 and H2O. The improved photocatalytic activity is mostly caused by the following factors. (1) Doping La ions can decrease the band gap of ZnO, enhance light response, and effectively enhance the separation rate of photo-generated holes and electrons. (2) MIL-53(Al) can adsorb SMT and promote the separation of electron. This work shows that the synthesized La-doped MIL-53(Al)/ZnO photocatalyst is expected to be used as a green and effective method for treatment of environment water pollution.

In this study, novel iron-doped biochar (Fe-BC) was produced using a simple method, and it was used as an H2O2 activator for tetracycline (TC) degradation. Generally, iron loading can improve the separation performance and reactivity of biochar (BC). In the Fe-BC/H2O2 system, 92% of the TC was removed within 30 min with the apparent rate constant (kobs) of 0.155 min−1, which was 23.85 times that in the case of the BC/H2O2 system (0.0065 min−1). The effects of the H2O2 and Fe-BC dosage, initial pH, and TC concentration on the TC removal were investigated. The radical quenching and electron paramagnetic resonance (EPR) measurements demonstrated that the removal of TC using the Fe-BC/H2O2 process involved both radical (•OH and O2−•) and non-radical pathways (1O2 and electron transfer). In addition, the performance of the catalyst was also affected by the persistent free radicals (PFRs) and defective sites on the catalyst. Moreover, the degradation pathways of TC were proposed according to the intermediate products detected by LC-MS and the ecotoxicity of intermediates was evaluated. Finally, the Fe-BC/H2O2 showed high resistance to inorganic anions and natural organic matter in aquatic environments. Overall, Fe-BC is expected to be an economic and highly efficient heterogeneous Fenton catalyst for removing the organic contaminants in wastewater.

Propranolol hydrochloride can be considered a persistent and bioaccumulative pharmaceutical in the environment. This drug and its by-products are potentially toxic and have adverse effects, since these compounds have been associated with endocrine-disrupting effects, reproductive deficiencies, embryo abnormalities and pericardial oedema. TiO2–La 0.05%–carboxymethyl-β-cyclodextrin (CMCD) nanoparticles were successfully prepared by a simple two-step method, which consists of sonification and functionalization. The characterization analyses reveal that lanthanum is dispersed on the semiconductor surface, probably forming Ti–O–La bonds, which can induce oxygen vacancies and surface defects that effectively restrain the recombination of photogenerated electron/holes pairs. The efficiency of TiO2–La 0.05%–CMCD samples in degradation of propranolol under UV-light irradiation is higher than that of pristine TiO2 within 20 min reaction, probably due to complex formation between the β-blocker and the oligosaccharide, which allows us to propose a photocatalytic mechanism based on the formation of intermediates and competition of these compounds to the radicals and CMCD cavities.

It is highly demanded to steer the charge flow in semiconductor for efficient photocatalytic environmental remediation. Herein, we designed an interfacial contact Ti3C2 MXene/ZnIn2S4 nanosheets (TC/ZISNS) Schottky heterostructure which could greatly enhance photogenerated charge separation of ZnIn2S4 (ZIS). Through TEM、XPS measurement, the strong interface coupling between 2D ZnIn2S4 nanosheets and 2D Ti3C2 MXene were explained, and the formation of Schottky heterostructure was demonstrated by electrochemical method. To investigate the photocatalytic activity of as-prepared samples, the photocatalytic reduction of Cr(VI) and photocatalytic oxidation degradation tetracycline hydrochloride (TC-H) experiments were carried out. The results showed that the Schottky catalyst (10%-TC/ZISNS) possessed the optimum photocatalytic efficiency. Especially, the apparent rate constant of Cr(VI) reduction with 10%-TC/ZISNS was 3.9 times than that of pure ZIS. The photocatalytic performance of 10%-TC/ZISNS toward degradation rate of TC-H was 1.8 times than that of pure ZIS. Finally, a possible mechanism for great enhancement of visible-light driven photocatalytic activity in the TC/ZISNS system was provided. On the whole, this work provided a new insight on 2D/2D contact Schottky heterostructure for enhancing photocatalytic activity.

The Electro-Fenton (EF) process is one of the promising advanced oxidation processes (AOPs) for environmental remediation. The H2O2 yield of EF process largely determines its performance on organic pollutants degradation. Conventional Pd-catalytic EF process generates H2O2 via the combination reaction of anodic O2 and cathodic H2. However, the relatively expensive catalyst limits its application. Herein, a hybrid Pd/activated carbon (Pd/AC)-stainless steel mesh (SS) cathode (PACSS) was proposed, which enables more efficient H2O2 generation. It utilizes AC, the support of Pd catalyst, as part of cathode for H2O2 generation via 2-electron anodic O2 reduction, and SS serve as a current distributor. Moreover, H2O2 could be catalytically decomposed upon AC to generate highly reactive ·OH, which avoids the use of Fe2+. Compared with conventional Pd catalyst, H2O2 concentration obtained by PACSS cathode is 248.2% higher, the O2 utilization efficiency was also increased from 3.2% to 10.8%. Within 50 min, 26.3%, 72.5%, and 94.0% H2O2 was decomposed by Pd, AC, and Pd/AC. Fluorescence detection results implied that Pd/AC is effective upon H2O2 activation for ·OH generation. Finally, iron-free EF process enabled by PACSS cathode was examined to be effective for reactive blue 19 (RB19) degradation. After continuous running for 10 cycles (500 min), the PACSS cathode was still stable for H2O2 generation, H2O2 activation, and RB19 degradation, showing its potential application for organic pollutants degradation without increase in the running cost.