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In this study, single-spherical nanoscale zero valent iron (nZVI) particles with large specific sur-face area were successfully synthesized by a simple and rapid chemical reduction method. The XRD spectra and SEM–EDS images showed that the synthesized nZVI had excellent crystal struc-ture, but oxidation products, such as γ-Fe2O3 and Fe3O4, were formed on the surface of the parti-cles. The effect of different factors on the removal of Cr(VI) by nZVI were studied, and the opti-mum experimental conditions were found. Kinetic and thermodynamic equations at different temperatures showed that the removal of Cr(VI) by nZVI was a single-layer chemical adsorption, conforming to pseudo-second-order kinetics. By applying the intraparticle diffusion model, the ad-sorption process was composed of three stages, namely rapid diffusion, chemical reduction, and in-ternal saturation. Mechanism analysis demonstrated that the removal of Cr(VI) by nZVI in-volved adsorption, reduction, precipitation and coprecipitation. Meanwhile, Cr(VI) was reduced to Cr(III) by nZVI, while FeCr2O4, CrxFe1−xOOH, and CrxFe1−x(OH)3 were formed as end products. In addition, the study found that ascorbic acid, starch, and Cu modified nZVI can promote the removal efficiency of Cr(VI) in varying degrees due to the enhanced mobility of the particles. These results can provide new insights into the removal mechanisms of Cr(VI) by nZVI. [ABSTRACT FROM AUTHOR]

Sodium borohydride (NaBH4) is considered a good candidate for hydrogen generation from hydrolysis because of its high hydrogen storage capacity (10.8 wt%) and environmentally friendly hydrolysis products. However, due to its sluggish hydrogen generation (HG) rate in the water, it usually needs an efficient catalyst to enhance the HG rate. In this work, graphene oxide (GO)-modified Co-B-P catalysts were obtained using a chemical in situ reduction method. The structure and composition of the as-prepared catalysts were characterized, and the catalytic performance for NaBH4 hydrolysis was measured as well. The results show that the as-prepared catalyst with a GO content of 75 mg (Co-B-P/75rGO) exhibited an optimal catalytic efficiency with an HG rate of 12087.8 mL min−1 g−1 at 25 °C, far better than majority of the findings that have been reported. The catalyst had a good stability with 88.9% of the initial catalytic efficiency following 10 cycles. In addition, Co-, B-, and P-modified graphene showed a synergistic effect improving the kinetics and thermodynamics of NaBH4 hydrolysis with a lower activation energy of 28.64 kJ mol−1. These results reveal that the GO-modified Co-B-P catalyst has good potential for borohydride hydrolysis applications. [ABSTRACT FROM AUTHOR]

The current work presents the electro-oxidation of olive mill and biodiesel wastewaters in an alkaline medium with the aim of hydrogen production and simultaneous reduction in the organic pollution content. The process is performed, at laboratory scale, in an own-design single cavity electrolyzer with graphite electrodes and no membrane. The system and the procedures to generate hydrogen under ambient conditions are described. The gas flow generated is analyzed through gas chromatography. The wastewater balance in the liquid electrolyte shows a reduction in the chemical oxygen demand (COD) pointing to a decrease in the organic content. The experimental results confirm the production of hydrogen with different purity levels and the simultaneous reduction in organic contaminants. This wastewater treatment appears as a feasible process to obtain hydrogen at ambient conditions powered with renewable energy sources, resulting in a more competitive hydrogen cost. [ABSTRACT FROM AUTHOR]

Background: Multidrug resistant MDR bacterial strains are causing fatal infections, such as mastitis. Thus, there is a need for the development of new target-oriented antimicrobials. Nanomaterials have many advantages over traditional antibiotics, including improved stability, controlled antibiotic release, targeted administration, enhanced bioavailability, and the use of antibiotic-loaded nanomaterials, such as the one herein reported for the first time, appear to be a promising strategy to combat antibiotic-resistant bacteria. The use of rationally designed metallic nanocomposites, rather than the use of single metallic nanoparticles (NPs), should further minimize the bacterial resistance. Aim: Green synthesis of a multimetallic/ternary nanocomposite formed of silver (Ag), titanium dioxide (TiO2), and iron(III) oxide (Fe2O3), conjugated to chitosan (CS), in which the large spectrum fluoroquinolone antibiotic ciprofloxacin (CIP) has been encapsulated. Methods: The metallic nanoparticles (NPs) Ag NPs, TiO2 NPs, and Fe2O3 NPs were synthesized by reduction of Moringa concanensis leaf aqueous extract. The ternary junction was obtained by wet chemical impregnation technique. CIP was encapsulated into the ternary nanocomposite Ag/TiO2/Fe2O3, followed by chitosan (CS) conjugation using the ionic gelation method. The resulting CS-based nanoparticulate drug delivery system (NDDS), i.e., CIP-Ag/TiO2/Fe2O3/CS, was characterized in vitro by gold standard physical techniques such as X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM), Fourier-transform infrared (FTIR) spectroscopy. Pharmacological analyses (i.e., LC, EE, ex-vivo drug release behavior) were also assessed. Further, biological studies were carried out both ex vivo (i.e., by disk diffusion method (DDM), fluorescence-activated single cell sorting (FACS), MTT assay) and in vivo (i.e., antibacterial activity in a rabbit model, colony-forming unit (CFU) on blood agar, histopathological analysis using H&E staining). Results: The encapsulation efficiency (EE) and the loading capacity (LC) of the NDDS were as high as 94% ± 1.26 and 57% ± 3.5, respectively. XRD analysis confirmed the crystalline nature of the prepared formulation. FESEM revealed nanorods with an average diameter of 50–70 ± 12 nm. FTIR confirmed the Fe-O-Ti-CS linkages as well as the successful encapsulation of CIP into the NDDS. The zeta potential (ZP) of the NDDS was determined as 85.26 ± 0.12 mV. The antimicrobial potential of the NDDS was elicited by prominent ZIs against MDR E. coli (33 ± 1.40 mm) at the low MIC of 0.112 μg/mL. Morphological alterations (e.g., deformed shape and structural damages) of MDR pathogens were clearly visible overtime by FESEM after treatment with the NDDS at MIC value, which led to the cytolysis ultimately. FACS analysis confirmed late apoptotic of the MDR E. coli (80.85%) after 6 h incubation of the NDDS at MIC (p < 0.05 compared to untreated MDR E. coli used as negative control). The highest drug release (89% ± 0.57) was observed after 8 h using PBS medium at pH 7.4. The viability of bovine mammary gland epithelial cells (BMGE) treated with the NDDS remained superior to 90%, indicating a negligible cytotoxicity (p < 0.05). In the rabbit model, in which infection was caused by injecting MDR E. coli intraperitoneally (IP), no colonies were detected after 72 h of treatment. Importantly, the histopathological analysis showed no changes in the vital rabbit organs in the treated group compared to the untreated group. Conclusions: Taken together, the newly prepared CIP-Ag/TiO2/Fe2O3/CS nanoformulation appears safe, biocompatible, and therapeutically active to fight MDR E. coli strains-causing mastitis. [ABSTRACT FROM AUTHOR]

The analysis of chemical oxygen demand (COD) plays an important role in measuring water pollution, but it normally has a high ecological price. Advances in image acquisition and processing techniques enable the use of mobile devices for analytical purposes. Here, the PhotoMetrix PRO application was used for image acquisition and multivariate analysis. Statistical analysis showed no significant difference in the results compared to the standard method, with no adverse effect of the volume reduction. The cost of analysis and waste generation were reduced by one third, while the analysis time was reduced by one fifth. The miniaturized method was successfully employed in the analysis of several matrices and for the evaluation of advanced oxidation processes. The AGREE score was improved by 25% due to miniaturization. For these reasons, the miniaturized PhotoMetrix PRO method is a suitable option for COD analysis, being less hazardous to the environment due to reductions in the chemicals used and in waste generation. [ABSTRACT FROM AUTHOR]

Special attention has recently been paid to surface-defective titanium dioxide and black TiO2 with advanced optical, electrical, and photocatalytic properties. Synthesis of these materials for photodegradation and mineralization of persistent organic pollutants in water, especially under visible radiation, presents interest from scientific and application points of view. Chemical reduction by heating a TiO2 and NaBH4 mixture at 350 °C successfully introduced Ti3+ defects and oxygen vacancies at the surface of TiO2, with an increase in the photocatalytic degradation of amoxicillin—an antibiotic that is present in wastewater due to its intense use in human and animal medicine. Three TiO2 samples were prepared at different annealing temperatures to control the ratio between anatase and rutile and were subjected to chemical reduction. Electron paramagnetic resonance investigations showed that the formation of surface Ti3+ defects in a high concentration occurred mainly in the anatase sample annealed at 400 °C, contributing to the bandgap reduction from 3.32 eV to 2.92 eV. The reduced band gap enhances visible light absorption and the efficiency of photocatalysis. The nanoparticles of ~90 m2/g specific surface area and 12 nm average size exhibit ~100% efficiency in the degradation of amoxicillin under simulated solar irradiation compared with pristine TiO2. Mineralization of amoxicillin and by-products was over 75% after 48 h irradiation for the anatase sample, where the Ti3+ defects were present in a higher concentration at the catalyst's surface. [ABSTRACT FROM AUTHOR]

Based on China's goal of achieving carbon neutrality by 2060, this study focused on its coal gasification in 2010–2019. Carbon emissions were calculated from industrial data, and an LMDt model was established to analyze the influencing factors of carbon emissions. Through scenario analysis, the paths of carbon emission reductions in the chemical industry were analyzed, and their emission reduction potential was estimated. The results showed that the carbon emissions in the chemical industry increased rapidly in 2010–2019, reaching 196 million tons in 2019. The emission structure was the most important factor in mitigating carbon emissions, and the emission intensity, industrial structure, economic development level, and labor force scale had different degrees of promotion effects, of which emission intensity was the strongest. The chemical industry can reach a carbon peak before 2030 under the three analyzed scenarios, and the emission reduction potential is the largest under the landing policy scenario. The results showed that carbon capture, usage, and storage (CCUS) technology is key for carbon emission reductions and that it is necessary to adjust the industrial structure, reduce emission intensity, and increase forest carbon sink to achieve carbon neutrality in the chemical industry. [ABSTRACT FROM AUTHOR]

This study explored the effect stage number and plant type have on ammonia-nitrogen (NH 3 –N) removal kinetics in a two-stage pilot-scale vertical flow constructed wetland (VFCW) system treating landfill leachate. Half of the VFCW columns were planted with Typha latifolia and the other half Scirpus californicus , and half of the columns were loaded with municipal solid waste landfill leachate (diluted to 1 part leachate to 2 parts total) with the effluent from these columns was collected in two separate barrels. The remaining columns were loaded with the effluent collected from the first columns, creating a two-stage VFCW system with four unique pairs to be tested. The leachate used here experienced no prior pre-treatment, and average influent concentrations of NH 3 –N for the first- and second-stage VFCWs were 508 and 321 mg L−1, respectively— much higher than many other VFCW treatment systems. Some reduction in chemical oxygen demand was observed, as well as generation of nitrate and nitrite, evidence of nitrification. No apparent correlation between aboveground biomass and removal of NH 3 –N was observed. Overall removal efficiency of NH 3 –N through two stages of VFCWs was 53.7% for columns planted with T. latifolia and 58.3% for those planted with S. Californicus. Average NH 3 –N removal efficiencies for the first stage VFCWs were 32.7% and 34.3%, while those in the second stage were 31.3% and 36.5%; no significant difference was observed between the first and second stage, suggesting that stage number does not have a significant effect on the removal efficiency of NH 3 –N in the primary treatment of landfill leachate via VFCWs. However, average mass removal rates of NH 3 –N in the first stage were 166 and 175 mg L−1 d−1; the second stage was significantly lower at 99.4 and 112 mg L−1 d−1, indicating that the first stage removed more pollutants overall. [Display omitted] • Nitrification and denitrification observed throughout entire experiment. • Stage number not found to have a significant impact on NH 3 –N removal. • Higher accumulation of nitrite observed on second day of each loading period. • Results reported as k-values and mass removal rates to better contextualize results. [ABSTRACT FROM AUTHOR]

The Modified Fischer-Tropsch process converts CO 2 to chemicals using a dual-function Fe-based catalyst composed typically of magnetite and iron carbides. However, catalyst deactivation limits its industrial application. In this study, we combined Density Functional Theory (DFT) calculations and experiments to provide insights into the underlying catalyst deactivation and regeneration mechanisms. The dynamic state of the catalyst was observed with time on stream, revealing the impact of the evolving reaction mixture along the reactor. Rapid CO 2 and H 2 O dissociation on the carbide phase creates persistent *O, causing Fe 5 C 2 deactivation through oxidation. On the other hand, the direct carburization of Fe 3 O 4 proves challenging due to significant energy barriers, underscoring the need for metallic Fe or a highly reduced surface as a precursor to effective catalyst activation. These insights into iron catalyst evolution during CO 2 reduction can guide the development of strategies for achieving efficient catalyst performance. [Display omitted] • Evolving reaction mixture drives catalyst's phase transformation and deactivation. • Persistent *O surface species from CO 2 and H 2 O dissociation oxidize the carbide phase to Fe 3 O 4 , causing deactivation. • Direct carburization of Fe 3 O 4 faces high energy barriers, highlighting the need for reduction before regeneration. [ABSTRACT FROM AUTHOR]

In this study, we aimed to use the loss of happy life expectancy (LHpLE), an indicator that enables risk assessment considering wellbeing, to compare the risks of environmental carcinogenic chemicals in Japan. First, we surveyed Japanese people to determine their emotional happiness by age and sex and evaluated whether cancer incidence reduced emotional happiness. Questionnaires were administered to a general population panel and a panel of patients with cancer in 2022, recruiting a predetermined number of responses of 5000 and 850, respectively. Second, using the survey data, LHpLE was calculated for radon, arsenic, and fine particulate matter (aerodynamic diameter <2.5 μm; PM 2.5) and compared to psychological distress, considering increased mortality and decreased emotional happiness due to these risks. We discovered no significant decrease in emotional happiness due to cancer incidence and no significant associations between emotional happiness and cancer type, history, or stage. LHpLE was calculated to be 6.4 × 10−3 years for radon, 2.6 × 10−3 years for arsenic, 1.1 × 10−2 years (2012 exposure) and 8.6 × 10−4 years (2020 exposure) for PM 2.5 , and 9.7 × 10−1 years for psychological distress. The fraction of losses caused by these carcinogenic chemicals to HpLE exceeded 10−5, suggesting that risk reduction for these chemicals is important in environmental policies. The LHpLE indicator allows for comparing different types of risks, such as environmental chemicals and psychological distress. This is the first study to compare chemical risks using the LHpLE indicator. [Display omitted] • We evaluated whether cancer incidence reduced emotional happiness. • We estimated the loss of happy life expectancy for environmental chemicals. • Cancer incidence did not reduce emotional happiness. • The loss of happy life expectancy exceeded 10−4 years for radon, arsenic, and PM 2.5 • The loss of happy life expectancy was 1 year for psychological distress. [ABSTRACT FROM AUTHOR]

[Display omitted] • Oxygen vacancies was successfully prepared by simple chemical reduction method. • OTC removal efficiency achieved highest of 95.7% in 2.5-OVs-CuFe 2 O 4 /PMS system. • Oxygen vacancies promoted rapid conversion of oxygen into reactive species. • Oxygen vacancies accelerated the conversion of Fe(Ⅱ)/Fe(Ⅲ) and Cu(Ⅰ)/Cu(Ⅱ). • Free radicals of HO , SO 4 − , O 2 – and non-radical of 1O 2 contributed to the OTC degradation. Peroxymonosulfate (PMS) based advanced oxidation methods have gained attention for eliminating antibiotics like oxytetracycline (OTC) from wastewater. This study presents an innovative approach by incorporating oxygen vacancies (OVs) into CuFe 2 O 4 to create OVs-CuFe 2 O 4 materials. Compared to traditional CuFe 2 O 4 , OVs-CuFe 2 O 4 offered superior catalytic performance due to its surface-rich OVs promoting rapid conversion of oxygen and efficient metal redox of Fe(Ⅱ)/Fe(Ⅲ) and Cu(Ⅰ)/Cu(Ⅱ). OVs-CuFe 2 O 4 /PMS achieved impressive 95.7 % OTC removal in 45 min with a rate constant of 0.107 min−1, which was 3.87 times of CuFe 2 O 4 /PMS. The OVs-CuFe 2 O 4 /PMS system exhibited a broad pH tolerance range of 3 to 11 with OTC removal efficiency above 89.3 %. The OVs-CuFe 2 O 4 /PMS system produced various free radicals and non-radical for OTC degradation. The OVs-CuFe 2 O 4 also has good stability with removal efficiency of 81.9 % at fourth cycle. This research gives a strategy to construct oxygen vacancies enrich catalysts for efficient activation of PMS and treatment of antibiotics wastewater. [ABSTRACT FROM AUTHOR]

A highly water-soluble and uniformly dispersed concentrate of silver nanoparticles (Ag NPs) hydrosols were synthesized using a chemical reduction method. The Ag NPs hydrosols exhibited remarkable antibacterial activity against sulfate-reducing bacteria (SRB) and can serve as a biocide for anti-corrosion purposes. The addition of 50 ppm Ag NPs hydrosols reduced the corrosion rate by over 91 % in the presence of SRB biofilm compared to untreated conditions. Numerous Ag NPs adsorbed onto the cell wall, with some internalizing and entering the cell, resulting in cytoplasmic efflux and DNA damage, ultimately leading to cell death. [Display omitted] • A controllable Ag NPs hydrosol was synthesized through the chemical reduction method. • The Ag NPs hydrosol exhibited a strong killing effect on SRB within biofilms. • Ag NPs were internalized and enter the cell, leading to cytoplasmic efflux and DNA damage. • The Ag NPs hydrosol reduced SRB resistance compared to traditional biocides. [ABSTRACT FROM AUTHOR]

Bismuth sulfide nanoparticles (BiS NPs) were synthesized via the hydrothermal method, and reduced graphene oxide(rGO) and silver nanoparticles (Ag), which acted as substrates, have prepared using the chemical reduction method. The synthesized nanoparticles have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible spectroscopy, and photoluminescence spectroscopy. Commercially available paracetamol-500 mg (PAM) and aspirin-300 mg (ASP) were selected for photodegradation under visible light using the as-prepared composites in an aqueous solution. Photoluminescence spectroscopy was used to detect PAM and ASP using the photo-excited electron transfer (PET) process, and the limit of detection (LOD) has obtained for PAM(8.70 ppm) and ASP(4.43 ppm) with a sensitivity of 0.9954 and 0.8002, respectively. Fourier transform infrared spectroscopy (FTIR) was used to analyze the before and after degradation products and to confirm the disintegrated products such as –COOH and –CH– both before and after disintegration.. The experimental data were found to fit well with the Freundlich isotherm, suggesting that the as-prepared nanocomposites exhibited a heterogeneous nature for PAM (5119 mg/L), and the pseudo-first-order kinetic model suggests ASP (1030 mg/L) with R2 values of 0.9119 and 0.7075. The risk assessment analysis of PAM was 9.823 μg/L(RQ > 1) and that of ASP was 0.2106 μg/L(RQ < 1), indicating that PAM has a higher potential risk than ASP. The demographic data of the participants indicated that PAM was the most stockpiled medicine at home; this work also encompasses the action of a single PAM and ASP tablet toward the environment, if it is accidently disposed of improperly could create massive water/soil pollution; hence, the care/duty of each person should follow the proper disposal of medical waste because we cannot replace this environment. • BiSNPs@rGO/Ag composites successfully detect and degrade PAM and ASP. • Detection utilizes photo-induced electron transfer through photoluminescence spectroscopy. • PAM degradation tendency surpasses that of ASP. • Risk assessment indicates PAM poses a higher soil/water pollution risk than ASP. • Demographic data emphasizes prompt separate collection of stockpiled pharmaceutical drugs. [ABSTRACT FROM AUTHOR]

The objective of the present study was to employ a green synthesis method to produce a sustainable ZnFe 12 O 19 /BiOI nanocomposite and evaluate its efficacy in the photocatalytic degradation of metronidazole (MNZ) from aqueous media. An artificial neural network (ANN) model was developed to predict the performance of the photocatalytic degradation process using experimental data. More importantly, sensitivity analysis was conducted to explore the relationship between MNZ degradation and various experimental parameters. The elimination of MNZ was assessed under different operational parameters, including pH, contaminant concentration, nanocomposite dosage, and retention time. The outcomes exhibited high a desirability performance of the ANN model with a coefficient correlation (R2) of 0.99. Under optimized circumstances, the MNZ elimination efficiency, as well as the reduction in chemical oxygen demand (COD) and total organic carbon (TOC), reached 92.71%, 70.23%, and 55.08%, respectively. The catalyst showed the ability to be regenerated 8 times with only a slight decrease in its photocatalytic activity. Furthermore, the experimental data obtained demonstrated a good agreement with the predictions of the ANN model. As a result, this study fabricated the ZnFe 12 O 19 /BiOI nanocomposite, which gave potential implication value in the effective decontamination of pharmaceutical compounds. [Display omitted] • Synthesized and characterized ZnFe 12 O 19 /BiOI as a new green magnetic nanocomposite. •The ZnFe 12 O 19 /BiOI/Xenon process was evaluated in actual pharmaceutical wastewater. •OH radicals was the prevailing species for photodecomposition of metronidazole. •The ZnFe 12 O 19 /BiOI was an efficient and highly stable photocatalyst. • Artificial neural network confirmed the laboratory data in this work. [ABSTRACT FROM AUTHOR]

[Display omitted] • Development of a scalable and robust Cu-ASTO/Au/CoO x -WO 3 composite photocatalyst sheet. • The sheet demonstrated enhanced charge separation efficiency via an indirect Z-scheme mechanism. • Efficient photoconversion of CO 2 and H 2 O using this innovative photocatalyst system. • Comprehensive testing of the photocatalytic CO 2 reduction performance in both indoor and outdoor settings. Perovskite oxides have emerged as promising photocatalysts for CO 2 reduction to valuable chemicals and fuels. However, conventional perovskite oxide photocatalysts often suffer from inefficient charge separation and bulk charge recombination, negatively impacting overall photoactivity. In this work, we present a novel immobilized perovskite oxide-based photocatalyst sheet featuring an indirect Z-scheme heterostructure composed of Cu-loaded Al-doped SrTiO 3 (Cu-ASTO) and CoO x -loaded WO 3 (CoO x -WO 3) with an ultrathin (20 nm) gold interlayer serving as a conductive bridge. We tested this photocatalyst sheet in a sealed reactor containing a CO 2 -saturated aqueous solution of 0.1 M NaHCO 3 and a side window to allow irradiation. Under irradiation with a 300 W Xe lamp, the Cu-ASTO/Au/CoO x -WO 3 immobilized photocatalyst sheet produced methane (CH 4) at a rate of 2.676 µmol cm-2 h−1 and methanol (CH 3 OH) at 0.517 µmol cm-2 h−1. We attribute the superior activity of this catalyst to the all-solid-state indirect Z-scheme heterostructure that greatly extends the lifespan of photoinduced charge carriers and enhances the CO 2 photoconversion reaction. In experiments conducted outside, we demonstrated the immobilized photocatalyst's performance under natural sunlight, producing CH 4 at 0.307 µmol cm-2 h−1 and CH 3 OH at 0.069 µmol cm-2 h−1. This work provides design ideas for developing robust immobilized photocatalyst systems for the scalable operation of the CO 2 photoreduction process and broadening the scope of applications for perovskite heterostructure photocatalysts. [ABSTRACT FROM AUTHOR]

Cu (II) is a toxic heavy metal commonly identified in groundwater contaminants. Bentonite-based cutoff wall is the most used method in isolating and adsorbing contaminants, while the bentonite in it easily to fail due to Cu(II) exchange. This study synthesized a novel material through the modification of calcium bentonite (CaB) utilizing sodium hexametaphosphate (SHMP) and nano zero-valent iron (NZVI). The characteristics, adsorption performance, and mechanism of the NZVI/SHMP-CaB were investigated comprehensively. The results showed that SHMP can disperse CaB and reduce flocculation, while NZVI can be further stabilized without agglomeration. The best adsorption performance of NZVI/SHMP-CaB could be obtained at the dosage of 2% SHMP and 4% NZVI. The NZVI/SHMP-CaB exhibited an outstanding removal efficiency of over 60% and 90% at a high Cu(II) concentration (pH = 6, Cu(II) = 300 mg/L) and acidic conditions (pH = 3–6, Cu(II) = 50 mg/L), respectively. The adsorption of Cu(II) by NZVI/SHMP-CaB followed a pseudo-second-order kinetic model, and fitting results from the Freundlich isothermal model suggested that the adsorption process occurred spontaneously. Besides the rapid surface adsorption on the NZVI/SHMP-CaB and ion exchange with interlayer ions in bentonite, the removal mechanism of Cu(II) also involved the chemical reduction to insoluble forms such as Cu0 and Cu 2 O. The generated FePO 4 covered the surface of the homogenized NZVI particles, enhancing the resistance of NZVI/SHMP-CaB to acidic and oxidative environments. This study indicates that NZVI/SHMP-CaB is a promising alternative material which can be used for heavy metal removal from contaminated soil and water. [Display omitted] • NZVI/SHMP-CaB, a novel material, was synthesized for the removal of heavy metals. • Adsorption performance and mechanism of NZVI/SHMP-CaB were investigated. • Optimal ratio of 2% SHMP and 4% NZVI to CaB provided best adsorption performance. • Cu(II) was removed by rapid adsorption, ion exchange, and chemical reduction. [ABSTRACT FROM AUTHOR]

Life as we know it is homochiral, but the origins of biological homochirality on early Earth remain elusive. Shallow closed-basin lakes are a plausible prebiotic environment on early Earth, and most are expected to have significant sedimentary magnetite deposits. We hypothesize that ultraviolet (200- to 300-nm) irradiation of magnetite deposits could generate hydrated spin-polarized electrons sufficient to induce enantioselective prebiotic chemistry. Such electrons are potent reducing agents that drive reduction reactions where the spin polarization direction can enantioselectively alter the reaction kinetics. Our estimate of this chiral bias is based on the strong effective spinorbit coupling observed in the chiral-induced spin selectivity (CISS) effect, as applied to energy differences in reduction reactions for different isomers. In the original CISS experiments, spin-selective electron transmission through a monolayer of double-strand DNA molecules is observed at room temperature—indicating a strong coupling between molecular chirality and electron spin.We propose that the chiral symmetry breaking due to the CISS effect, when applied to reduction chemistry, can induce enantioselective synthesis on the prebiotic Earth and thus facilitate the homochiral assembly of life’s building blocks. [ABSTRACT FROM AUTHOR]

A gold nanoparticles transparent electrode was realized by chemical reduction. This work aims to compare the transparent gold nanoparticles electrode with a more commonly utilized gold-film-coated electrode in order to investigate its potential use as counter-electrode (CE) in dye-sensitized solar cells (DSSCs). A series of DSSC devices, utilizing I−/I3− and Co(III)/(II) polypyridine redox mediators [Co(dtb)3]3+/2+; dtb = 4,4′ditert-butyl-2,2′-bipyridine)], were evaluated. The investigation focused firstly on the structural characterization of the deposited gold layers and then on the electrochemical study. The novelty of the work is the realization of a gold nanoparticles CE that reached 80% of average visible transmittance. We finally examined the performance of the transparent gold nanoparticles CE in DSSC devices. A maximum power conversion efficiency (PCE) of 4.56% was obtained with a commercial I−/I3−-based electrolyte, while a maximum 3.1% of PCE was obtained with the homemade Co-based electrolyte. [ABSTRACT FROM AUTHOR]

The selective chemical conversion of biomass components to useful bioproducts may contribute to a renewable resource-based economy. The selective production of target bioproducts may be accomplished using heterogeneous catalysts operating under relatively moderate reaction conditions. In this work, carbohydrate biomass derived α-angelica lactone (AnL) and levulinic acid (LA) were converted to the versatile bioproduct γ-valerolactone (GVL), in the presence of nanohybrid catalysts (M-FDCA) and the microcrystalline metal-organic framework CAU-28, all of which were synthesized from bio-based 2,5-furandicarboxylic acid (FDCA) and a metal (M = Zr or Hf) precursor. The nanohybrids were prepared in a simple fast (FT) fashion, and, for comparison, via a conventional solvothermal (S) procedure. The M-FDCA catalysts stood on a higher footing than CAU-28 in the conversion of AnL and LA to GVL. The superior results for the M-FDCA catalysts may be partly due to their higher ratio S ext :S BET and nano-features, which may advantageously enhance active sites accessibility. In particular, the Hf-FDCA catalysts were stable and performed superiorly to the Zr-FDCA ones. Experimental mechanistic studies shed light on the multifunctional behavior of the hybrid catalysts in the one-pot conversion of AnL-to-GVL, which involved acid and reduction chemistry. [Display omitted] • Fast synthesis of biobased 2,5-furandicarboxylic acid (FDCA), Zr and Hf nanohybrids. • Catalyst benchmarking with microcrystalline metal-organic framework CAU-28. • Hf-FDCA best-performing in one-pot conversion of angelica lactone to γ-valerolactone. • Catalyst multifunctionality associated with -COOH of the linker and metal sites. • Hf-FDCA also best performing for levulinic acid to γ-valerolactone in 2-butanol. [ABSTRACT FROM AUTHOR]

Ravishing red luminescent Eu3+-activated SnO 2 quantum dot (QD) phosphors were successfully synthesized by employing a simple chemical reduction method. X-ray diffraction analysis confirmed that the Eu3+:SnO 2 QDs have a tetragonal structure. The particle size, interplanar distances, and elements existing in the sample were examined by performing transmission electron microscopy, high-resolution transmission electron microscopy, and elemental mapping studies, respectively. Under UV illumination, photoluminescence analyses were performed on pristine SnO 2 QDs and Eu3+:SnO 2 QDs. Under 294 nm of excitation, a broad emission band was observed for the undoped SnO 2 QDs centered at 454 nm. A robust red emission emitted from the Eu3+-activated SnO 2 QDs by excitation at 394 nm. The red emission intensity was significantly enhanced by increasing the Eu3+ ion concentration up to 0.3 mol%, and it was decreased drastically by increasing at above 0.3 mol% of Eu3+ ions due to concentration quenching. Furthermore, an energy migration was observed from SnO 2 QDs host to Eu3+ ions. The International Commission on Illumination (CIE) color coordinates, correlated color temperature, and color purity values were evaluated for all the Eu3+:SnO 2 QDs based on the emission profiles. The obtained CIE coordinates were compared with the standard National Television System Committee coordinates. Additionally, the applicability of the Eu3+:SnO 2 QDs was evaluated to visualize the latent fingerprints on smooth surfaces using the powder dusting method. The obtained latent fingerprint images exhibited good sensitivity, high contrast, and appreciable ridge details. The noncytotoxicity of the Eu3+:SnO 2 QDs was confirmed by conducting a toxicity test on normal fibroblast cell lines (L929). The results revealed that the noncytotoxic and ravishing luminescent Eu3+:SnO 2 QDs can garner significant interest for use in latent fingerprint, biological labeling, imaging, and security encoding. We believe that such a method of producing lanthanide-doped QDs can accelerate the development of QD phosphor-based research. [ABSTRACT FROM AUTHOR]

The fine particles generated by the foundry industry are present in the atmosphere; they have an impact on the climate because of their influence on atmospheric radioactive phenomena. As a result of this scenario, there is a rising amount of legislation restricting the emission of pollutants from foundry industries and related businesses. In response to this situation, many researchers have concentrated on end-of-pipe technologies, one of which is the wet scrubber, which is a device that is primarily used in foundries to control pollution and is one of the devices that has been incorporated. The disadvantage of using this wet scrubber, on the other hand, is that it contributes to secondary pollution when it is used. In order to combat secondary pollution, a model of an enhanced wet scrubber system that incorporates a multi-sand filtering technology was developed. The performance of this redesigned wet scrubber system was evaluated with the use of computational fluid dynamics (CFD) software. In CFD, the Reynolds stress model was applied for simulation. The pressure magnitudes and velocity magnitudes are obtained by this simulation. The volume fraction of the dust was evaluated through the DPM approach. Because of the introduction of the filtration tank's computation, it was discovered that successful filtration was accomplished using sand filters, meaning that environmental chemicals and particles were totally filtered from 0.17 kg at the entrance to zero kg of particles at the outflow. [ABSTRACT FROM AUTHOR]

This work reports on the fabrication of a novel planar reduced graphene oxide (rGO) memristor (MR) device. For the first time in the literature, the MR tunable resistive switching behavior is controlled by the GO reduction time at a constant temperature. The device is fabricated using standard microfabrication techniques on a flexible cyclic olefin copolymer substrate (COC). Thermal reduction of the GO layer at low temperatures (100 °C) avoids the drawbacks of chemical reduction methods such as toxicity and electrode metal damage during fabrication, while allowing for fine-tuning of the MR's switching behavior. The device has analog switching characteristics, with a range of different resistance states. By taking advantage of the slow nature of GO thermal annealing, the switching properties of the rGO memristors can be precisely controlled by adjusting the reduction period. At short annealing times (i.e., T < 20 h), the devices switch from high to low resistance states, while at longer annealing times the switching behavior is reversed, with the device switching from low to high resistance states (LRS to HRS). Resistive switching occurs as a result of the diffusion and removal of the oxygen functional groups in the GO film caused by Joule heating induced by the electric current. Complete electrical characterization tests are presented along with wettability and X-ray diffraction (XRD) tests. This work opens a new vision for realizing rGO-based MR devices with tunable switching properties, broadening the application horizon of the device. [ABSTRACT FROM AUTHOR]

The synthesis of nanoparticles from noble metals has received high attention from researchers due to their unique properties and their wide range of applications. Silver nanoparticles (AgNPs), in particular, show a remarkable inhibitory effect against microorganisms and viruses. Various methods have been developed to obtain AgNPs, however the stability of such nanostructures over time is still challenging. Researchers attempt to obtain particular shapes and sizes in order to tailor AgNPs properties for specific areas, such as biochemistry, biology, agriculture, electronics, medicine, and industry. The aim of this study was to design AgNPs with improved antimicrobial characteristics and stability. Two different wet chemical routes were considered: synthesis being performed (i) reduction method at room temperatures and (ii) solvothermal method at high temperature. Here, we show that the antimicrobial properties of the obtained AgNPs, are influenced by their synthesis route, which impact on the size and shape of the structures. This work analyses and compares the antimicrobial properties of the obtained AgNPs, based on their structure, sizes and morphologies which are influenced, in turn, not only by the type or quantities of precursors used but also by the temperature of the reaction. Generally, AgNPs obtained by solvothermal, at raised temperature, registered better antimicrobial activity as compared to NPs obtained by reduction method at room temperature. [ABSTRACT FROM AUTHOR]

The word "nano" means; one in a billion of a physical mass. Nanotechnology has been frequently beneficial branch of science in recent years by applying nanoparticules to various fields. Synthesis of particules in nano is size, has increased the covered surface area in unit volume and this made expanding of using nanoparticules in many different areas. Especially the metal nanoparticules have many advantages leading to development of many ways of synthesis. One of these methods of synthesis is "chemical reduction". This work makes a research on the anion effects on the size mass nanoparticules of metals Cu(II), Ni(II), Co(II), Zn(II) and Mn(II) after reduction to nano size of sodium bor hidrur which belongs to salt of acetate and chloride, nitrate, sulfate. Depending on the radius ratios and solubility values of metal cations and anions, the nanoparticule obtained from Cu(CH3COO)2 salt has the smallest radius. Nanometal particules with the largest radius were obtained by reduction of Cl- ion salts. Size analysis and scanning electron microscope (SEM) analysis made about the characterization of synthesised nano particules. [ABSTRACT FROM AUTHOR]

This study investigated the effects of the surface modification of gold nanoparticles (AuNPs) with negative, positive, and polar uncharged amino acids on hydroxyapatite formation under calcium-deficient conditions. The AuNPs were prepared using a chemical reduction method and capped with eight different amino acids. The different amino acid (AA) side chains had different interactions with the AuNPs, as indicated by the different shifts in the ultraviolet–visible spectra. The calcium and phosphor sources were added at the same concentration to obtain calcium-deficient hydroxyapatite (CDHA). X-ray diffraction revealed the presence of amino acid-capped AuNPs during synthesis resulting in CDHA with low crystallinity. The calculated crystallinity index (CI) indicated that aspartic acid could promote the crystallization of biomimetic hydroxyapatite. The crystallite size decreased by 6%–62%, which is beneficial for osteoinductivity in bone substitute applications. The involvement of AA-AuNPs in the synthesized hydroxyapatite resulted in apatite with a higher Ca/P ratio than that of the control except for cysteine, lysine, and glutamine. The morphology of the samples ranged from quasi-spherical to needle-like, which can potentially be used as an osteoinductive material. [ABSTRACT FROM AUTHOR]

Copper nanoparticles (CuNP) have been synthesized by using chemical reduction method using copper sulphate pentahydrate (CuSO4.5H2O) and ascorbic acid (C6H8O6) and distilled water as a solvent. The process was accelerated using microwave irradiation. The ascorbic acid was used both as reducing and capping agent. The synthesized material was studied by UV-Vis spectroscopy, FTIR spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX). The UV-Vis spectra showed a CuNP plasmon peak at 561 nm and FTIR showed the functional groups present with their absorption peaks which suggested that copper nanoparticles were surrounded by different organic molecules. The XRD revealed Cu and Cu2O with crystallite size 40 nm and 45 nm, respectively. EDX spectroscopy confirmed the existence of Cu and O. [ABSTRACT FROM AUTHOR]

Understanding the self‐assembly behavior of peptides is crucial for the design and synthesis of functional peptide‐based nanomaterials for various applications. In this study, a bifunctional peptide molecule with a sequence of KIIIIKYWYAF is designed, which reveals multiple functions for self‐assembling formation of peptide nanofibers (PNFs), noncovalent graphene oxide (GO) binding, and biomimetic metallization of nanoparticles (NPs). Well‐defined PNFs are obtained through the optimization of experimental conditions, which are further utilized to bind with GO to form GO/PNF nanohybrids via noncovalent interactions. Ascribed to the biomimetic function of peptide molecules, bimetallic gold‐platinum NPs (Au‐Pt NPs) are created along the PNFs by metallic ion adsorption and subsequent chemical reduction. The synthesized GO/PNF/Au‐Pt nanohybrids reveal improved electrochemical activity compared to Au, Pt, and Au‐Pt NPs, indicating potential contributions of both GO and PNFs to the final electrochemical sensing performance of the GO/PNF/Au‐Pt‐based electrodes. The fabricated electrochemical non‐enzymatic biosensors exhibit a detection limit of 0.379 µm and linear detection ranges of 1 µm–1 mm and 1–20 mm. The current study provides a facile strategy for the creation of peptide‐based superstructures with multiple functions and will inspire the design and synthesis of graphene‐peptide based nanomaterials for biomedicine, tissue engineering, and bioanalysis applications. [ABSTRACT FROM AUTHOR]

[Display omitted] In this work, pristine and NaBH 4 etched CeO 2 nanorods supported ruthenium (Ru) catalysts were synthesized and employed to investigate the effects of chemical etching and reduction activation treatment on CO oxidation. With 1 wt% Ru loading, the CeO 2 nanorods supported catalyst samples, after 6 wt% NaBH 4 etching treatment, showed significantly promoted H 2 consumption under 100 °C and low apparent activation energy (i.e., E a ∼ 31.2 kJ/mol) for CO oxidation. In - situ CO-DRIFTS profiles revealed that, for the reduced sample, the observed CO adsorption at ∼ 2020 cm−1 at 40 °C may be related to a strong RuO x -CeO 2 interaction induced by the NaBH 4 etching treatment, which was supported by the oxygen vacancy analysis results of X-ray photoelectron spectroscopy and CO-temperature programmed desorption. The enriched surface defects on CeO 2 support due to the chemical etching and reduction treatments are believed to promote the interaction between RuO x species and CeO 2 , which is responsible for the enhanced activity of CO oxidation. [ABSTRACT FROM AUTHOR]

A novel formic acid-assisted etching protocol has been developed to construct nirogen vacancies (NVs) on the ploymeric carbon nitride (PCN) surface. The NVs endows PCNs with an increased charge separation efficiency, and enhanced CO 2 activation. This NVs-PCN photocatalyst achieves superior CO 2 reduction activity with visible light. [Display omitted] • A novel formic acid-assisted etching method was developed for nitrogen vacancies (NVs) implantation in polymeric carbon nitride (PCN). • The NVs modification can promote the activation and reduction of CO 2. • This NVs-PCN displays exceptional catalytic activity for CO 2 reduction with visible light. • The relationship between the NVs and the CO 2 reduction catalysis has been established. Photocatalytic CO 2 reduction into valuable chemicals and fuels is thought to be an effective way to reduce greenhouse gas emissions and achieve sustainable carbon cycling. Recent studies have confirmed that polymeric carbon nitride (PCN) can drive CO 2 reduction reaction under visible light irradiation. However, the pristine PCN typically suffers from moderate efficiency. Herein, nitrogen-vacancies-functionalized PCN (NV S -PCN) photocatalysts are successfully prepared via a novel formic acid-assisted etching protocol for the first time. It is found that the NVs are mainly stemmed from the selectively breaking of surface N-(C) 3 sites within PCN matrix. Steady-state photoluminescence (PL), time-resolved PL, and photocurrent results approve that the NVs can significantly suppress the recombination of photogenerated charge carriers. CO 2 temperature programmed desorption and DFT calculations determine that the NVs modification can optimize the electronic properties of NVs-PCN photosystem, and thus considerably improve the activation of CO 2 , while lower the formation barrier of COOH* intermediates. Consequently, the NVs-PCN photosystem exhibits a 279-fold improvement in CO 2 reduction activity over the pristine PCN under 400 nm light irradiation. Moreover, we successfully prepare another NVs-modified PCN-T (trithiocyanuric acid as a precursor) under the same preparation conditions. This NVs-PCN-T photosystem also shows exceptional performances for photocatalytic CO 2 reduction and hydrogen production with visible light. The apparent quantum yields (AQYs) for CO 2 reduction and hydrogen production reach as high as 6.17 % and 31.08 % at 400 nm, respectively. The insights provided in this work are expected to provide a novel clue for manipulating catalytic properties and advancing the in-depth understanding on the role of defect structure of photocatalysts during CO 2 reduction. [ABSTRACT FROM AUTHOR]

Agriculture is important in the food production sector and, to meet all the food demand of the population, the agricultural sector has modernized, using chemical control in agriculture to control pests, diseases and weeds. The objective of this work was to carry out a literature review on the problems of chemical control in agriculture from an agricultural perspective, in order to demonstrate how chemical control affects the agricultural sector. The present study was developed based on the review of literature and relevant research based on data from the years between 2015 to 2021, using articles and data in Portuguese on academic google, using chemical control problems and the perspective of agriculture with agrochemicals as keywords. To ensure the production of crops, crop management must be carried out correctly, and the control of pests, diseases and weeds that affect crops, for this, one of the methods used today is chemical control. With the use of chemical control, it made it possible for agriculture to achieve large productions with the benefits provided by its use in the control of pests, diseases and weeds, but it brought with it some problems in its use, whether in the social, environmental and social spheres. Due to the problems caused by the large use of agrochemicals and the search for sustainable rural development, other alternative methods are adopted in agriculture, such as biological and cultural control, which has brought many benefits, one of which is the reduction of the use of chemical control. In agriculture, reducing costs and helping to maintain the sustainability of the entire agricultural production sector. In this way, the inadequate use of chemical control has brought and brings problems, such as contamination and intoxication in the environment and to human beings, in addition to problems related to resistance to pests, diseases and weeds, making their control more expensive, requiring the adoption of other methods. control methods, such as cultural control and biological control, which have in themselves more sustainable characteristics, thus reducing the use of agrochemicals in agriculture and reducing the problems caused by their use. [ABSTRACT FROM AUTHOR]

The homeostatic control of Sodium (Na+) ion in the human body assumes paramount relevance owing to its physiological importance. Any deviation from the normal level causes serious health problems like hypernatremia, hyponatremia, stroke, kidney problems etc. Therefore, quantification of Na+ levels in body fluids has significant diagnostic and prognostic importance. However, interfering ions like Potassium ion (K+) is the major hurdle in sodium detection. In this work, we synthesized the clusters of 3–9 nm-sized highly stable and pure Copper nanoparticles surface functionalised with curcumin, through chemical reduction method. Each cluster of particles is encapsulated in a curcumin layer which is clearly visible in TEM images. The results show that these curcumin functionalized Cu NPs (CuC) are highly selective to the colorimetric detection of Na+. The ions like K+, Mg2+ and Zn2+ did not interfere with the Na+ in this sensing technique. Low-cost paper-based sensor strips are fabricated and calibrated for the sensing of sodium in the physiological range and shade cards were developed as a calorimetric guide for estimation of Na+ which makes them ideal point of care diagnostic platform. We demonstrate that the proposed CuC paper strip can be used for detecting Na+ concentration within the whole physiological range in both blood serum and urine. [ABSTRACT FROM AUTHOR]

This study focused on the reduction of chemical oxygen demand (COD) from gas refinery wastewater via copper oxide nanoparticles which loaded on activated carbon supplied from Terminalia catappa (CuO-NPs-TCW-AC), while accordingly understudy process was accelerated by decomposition of organic pollutants in the presence of H2O2 as oxidant. CuO-NPs-TCW-AC as heterogeneous catalyst in the combination of H2O2 lead to generating OH radical as most efficient species degradation of organic pollutants (it is expected that copper ions also exhibited somewhat Fenton-like behaviors). TCW-AC prepared by carbonization at 850 °C for 90 min and subsequently was activated with CO2 at 900 °C for 90 min and TCW-AC as the final product was oxidizing with nitric acid and hydrochloric acid solution. Characterization of adsorbent and investigation of mechanism process were undertaken by FT-IR (before and after COD removal), pHZPC, Boehm's titration method, SEM, XRD, BET, and BJH. Conduction of preliminary experiments reveals that setting experimental condition at their optimum values including 0.06 g of the CuO-NPs-TCW-AC, pH of 4 and 0.1 mol L−1 of H2O2 at 75 °C following 5 min agitation at speed of 400 rpm leads to 61.5% reduction of initial COD (320 ppm) from gas refinery wastewaters. According to the coefficients of determination (R2) for Langmuir (0.985), Freundlich (0.993) and Temkin isotherm (0.981) reveal cooperative mechanism on whole adsorption/decomposition process, while its experimental and calculating maximum adsorbent capacity were 250.1, 263.2 (mg g−1), respectively. Judgment based on correlation coefficients represents an agreement among experimental and predicted adsorption capacity and confirms that understudy COD reduction using CuO-NPs-TCW-AC follows the second-order kinetics. The negative Gibbs free energy strongly support the high tendency of present material for COD through spontaneous while, higher adsorption rate by temperature rising confirm the endothermic nature of the process. As a result, the application of CuO-NPs-TCW-AC in the combination of H2O2 is suggested as a powerful tool for COD reduction from gas refinery wastewater. [ABSTRACT FROM AUTHOR]

Cytochrome c oxidase (CcO) is the terminal enzyme in the electron transfer chain in the inner membrane of mitochondria. It contains four metal redox centers, two of which, CuB and heme a3, form the binuclear center (BNC), where dioxygen is reduced to water. Crystal structures of CcO in various forms have been reported, from which ligand-binding states of the BNC and conformations of the protein matrix surrounding it have been deduced to elucidate the mechanism by which the oxygen reduction chemistry is coupled to proton translocation. However, metal centers in proteins can be susceptible to X-ray-induced radiation damage, raising questions about the reliability of conclusions drawn from these studies. Here, we used microspectroscopy-coupled X-ray crystallography to interrogate how the structural integrity of bovine CcO in the fully oxidized state (O) is modulated by synchrotron radiation. Spectroscopic data showed that, upon X-ray exposure, O was converted to a hybrid O* state where all the four metal centers were reduced, but the protein matrix was trapped in the genuine O conformation and the ligands in the BNC remained intact. Annealing the O* crystal above the glass transition temperature induced relaxation of the O* structure to a new R* structure, wherein the protein matrix converted to the fully reduced R conformation with the exception of helix X, which partly remained in the O conformation because of incomplete dissociation of the ligands from the BNC. We conclude from these data that reevaluation of reported CcO structures obtained with synchrotron light sources is merited. [ABSTRACT FROM AUTHOR]

Eric Scerri is the world-leading expert on (the history of) Periodic Table and was quite recently named the second-most influential academic in the field of chemistry over the last decade by Academic Influence. In this interview we discuss his main questions of interest in the philosophy of chemistry—the question of reduction of chemistry to physics and the dual sense of chemical element—in the context of his main study object, the periodic table of elements. Among other things, we touch upon the more specific issues related to chemical classification, such as pair reversal, the placement and order of certain elements, the structure and shape of periodic table, etc. We also discuss the status of chemical kinds as a traditional epitome of 'natural kinds', the relevance of philosophy of chemistry for chemical science, the implications of 'turn to practice' for philosophy of chemistry, and many other issues. Finally, Eric Scerri also discusses his most recent book, 'What is a Chemical Element?', co-edited with Elena Ghibaudi and published by Oxford University Press in 2020. [ABSTRACT FROM AUTHOR]

To address the secondary pollution problem of chemical reduction and the defects of a long bioremediation period for the soil around a chromium (Cr) salt plant in China, calcium polysulfide (CPS) combined with biostimulation (adding nutrient solution with glucose and urea) was used to reduce and stabilize hexavalent chromium [Cr(VI)] in the soil. The results showed that the remediation effect of adding CPS and nutrient solution was better than that of CPS alone for Cr(VI)-contaminated soil. An amount of 2.15% CPS with the Cr(VI) concentration reduced to approximately 330.0 mg/kg was selected as the optimal reducing agent dosage. Following the addition of 11 g/kg glucose and 13 g/kg urea, the degradation rate of Cr(VI) reached over 92% after 3 days, and the water-soluble fraction decreased by 95.6% after 40 days. The stability of the Cr was significantly enhanced. The correlation and regression analyses of Cr speciation indicated that the water-soluble fraction had significant negative correlations with the iron-manganese (Fe-Mn) oxide-bound fraction and the organic matter-bound fraction. There were significant negative correlations between the exchangeable fraction and the carbonate-bound fraction as well as extremely significant positive correlations between the Fe-Mn oxide-bound fraction and the organic matter-bound fraction. It was speculated that both the Fe-Mn oxide-bound fraction and the organic matter-bound fraction were transformed from the water-soluble fraction, and the exchangeable fraction and the carbonate-bound fraction were mutually transformed. This study enables us to acquire more knowledge about the speciation transformation of Cr in soil and provides an efficient, low-cost, and low-risk technology for the remediation of high Cr(VI)-contaminated soil. [ABSTRACT FROM AUTHOR]

In this manuscript, we accomplished the engineering of poly(methacrylic acid) [p(MAA)] micron-sized microgel (MG) integrated with silver nanoparticles (AgNPs). The micron-sized p(MAA) MG particles were synthesized by inverse suspension polymerization, and fabrication of silver nanoparticles was carried out via chemical reduction of Ag(I) ions in the synthesized MG network. The synthesized p(MAA) MG and p(MAA)–AgNPs composite was subjected for compositional and morphological analysis with Fourier transform infrared (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-ray diffraction (XRD), spectroscopy, and thermal gravimetric analyzer (TGA). The p(MAA) MG particles were observed to be spherical in shape with diameters in the range of 60–95 µm and found thermally stable below 225 °C. The existence of Ag in the p(MAA) MG was approved by EDX analysis. The prepared p(MAA)–AgNPs composite exhibited promising catalytic performance in the reduction of four different nitro-aromatic compounds including 4-nitrophenol (4-NP), 2-nitrophenol (2-NP), 2-nitroaniline (2-NA), and 4-nitroaniline (4-NA) with maximum reduction rates of 0.4205, 1.1222, 0.5195, and 1.6424 min−1, respectively. The catalyst was recycled for five consecutive cycles by a cost and time-effective process of filtration with gradual decrease in the catalytic activity to 10%. Also, the prepared p(MAA)–AgNPs composite was found active against Gram-negative E. coli and Gram-positive S. aureus with corresponding inhibition zones of 7 mm and 9 mm, respectively. [ABSTRACT FROM AUTHOR]

In this work, via the method of wet impregnation and chemical reduction, low-cost and available bentonite modified by cetyltrimethylammonium bromide (CTAB) was utilized as support to synthesize a novel organobentonite-supported Pd composite catalyst used for the catalytic transfer hydrogenation (CTH) of polyunsaturated fatty acid methyl ester (FAME). According to the results of characterization analysis, the organic modifier of CTAB was intercalated into the interlayer of bentonite, and the active metal Pd was immobilized and uniformly dispersed in the prepared composite catalyst. The possible formation mechanism of composite catalyst was proposed. The synthesized composite catalyst presented higher hydrogenation activity and selectivity compared with the pure nano-Pd catalyst. Moreover, the excellent stability remained for the composite catalyst after five catalytic runs in FAMEs hydrogenation. Hence, bentonite, as an economical and promising feedstock, could be used to synthesize a high-efficient and stable supported Pd composite catalyst successfully for the CTH of FAME. Low-cost bentonite, used as raw material, was modified by cetyltrimethylammonium bromide (CTAB) through the cation exchange process, forming organobentonite (OB) with an increased interlayer spacing. The cations of CTAB might be absorbed into the interlayers and on the surface of bentonite. The Pd ions were introduced through the impregnation of precursor solution of Pd (H2PdCl4) and bound to the cations of CTAB via electrostatic interactions. After the chemical reduction process by using NaBH4, the anionic PdCl42− could be reduced to metal Pd, which was immobilized and dispersed in the interlayers and on the surface of organobentonite, and then a novel Pd/OB composite catalyst formed. According to the result of TEM measurement, Pd particles showed the spheroidal shapes and dispersed uniformly in the synthesized composite catalyst. [ABSTRACT FROM AUTHOR]

The preparation of Ru nanoparticles supported on γ-Al2O3 followed by chemical reduction using RuCl3 as a precursor is demonstrated, and their properties are compared to Ru nanoparticles supported on γ-Al2O3 prepared by impregnation of γ-Al2O3 with Ru3(CO)12 and subsequent thermal decomposition. The Ru nanoparticles resulting from chemical reduction of RuCl3 are slightly larger (1.2 vs. 0.8 nm). In addition, Ru nanoparticles were deposited on Stöber SiO2 using both deposition techniques. These particles were larger than the ones deposited on γ-Al2O3 (2.5 and 3.4 nm for chemical reduction and thermal decomposition, respectively). Taking into account the size differences between the Ru nanoparticles, all catalysts display similar activity (0.14–0.63 mol·gRu−1·h−1) and selectivity (≥99%) in the sunlight-powered Sabatier reaction. Ergo, the use of toxic and volatile Ru3(CO)12 can be avoided, since catalysts prepared by chemical reduction of RuCl3 display similar catalytic performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Plasmonic Cu 6 Sn 5 bimetal was prepared using chemical reduction method. • Photocatalytic activity was enhanced for Cu 6 Sn 5 after combined with polyaniline. • A mechanism of plasmon-driven photocatalytic water splitting was proposed. A plasmonic Cu 6 Sn 5 /polyaniline (Cu 6 Sn 5 /PANI) nanocomposite was synthesized by chemical reduction and hydrothermal methods. The best photocatalytic overall water splitting performance was achieved by the Cu 6 Sn 5 /PANI 3wt% composite, which contains 3 wt% PANI, which is approximately three times more than that of pure Cu 6 Sn 5. Meanwhile, Cu 6 Sn 5 /PANI 3wt% exhibited excellent photocatalytic stability for water splitting during the stability investigation. The dramatic promotion of the photocatalytic activity performance can be ascribed to the cocatalyst PANI. The existence of PANI can remarkably promote the separation and transfer efficiency of the photoinduced electron-hole pairs, and therefore enhance the photocatalytic activity. Our results also verify that the photogenerated charge comes from plasmonic Cu 6 Sn 5 with the surface plasmon resonance (SPR) effect, which is different from traditional semiconductor-based photocatalysts. This work sheds some light on plasmonic photocatalyst development and provides an alternative pathway for photocatalytic reactions. [ABSTRACT FROM AUTHOR]

The study of non-Saccharomyces yeasts in wine fermentations allows the exploration of new alternatives for the reduction of ethanol in wines. The objective of this work was to evaluate the fermentation capacity of two indigenous Candida yeasts (C. oleophila and C. boidinii) in monoculture and sequential fermentations (laboratory and microvinification scale) to produce Chilean Sauvignon Blanc wine. Fermentations were monitored by the determination of ethanol, glycerol, organic acids, and residual sugars. The results indicated that at the laboratory scale for both the monoculture and sequential fermentations it was possible to reduce the ethanol concentration on 0.77% v/v (monoculture) and 1.5% v/v (sequential) for C. oleophila and 0.50% v/v (monoculture) and 0.04% v/v (sequential) for C. boidinii compared to S. cerevisiae (12.87% v/v). Higher glycerol concentrations were produced in monoculture than sequential fermentations (C. oleophila: 9.47 g/L and C. boidinii 10.97 g/L). For microvinifications, the monoculture and sequential fermentations with C. boidinii managed to reduce ethanol content by 0.17% v/v and 0.54% v/v, respectively, over the S. cerevisiae control (13.74% v/v). In the case of C. oleophila, the reduction was only observed in sequential fermentations with 0.62% v/v. Interestingly, grapes with higher sugar concentration resulted in wines with lees ethanol concentrations. This might be associated to the use of C. oleophila (13.12% v/v) and C. boidinii (13.20% v/v) in sequential fermentations microvinification scale. [ABSTRACT FROM AUTHOR]

Waste sludge disintegration and bound water reduction was investigated by comparative chemical oxidation using calcium hypochlorite, hydrogen peroxide, peroxymonusulfate and peroxydisulfate in the study. Response surface methodology (RSM) with Box-Benhken Design (BBD) was used to determine operating parameters namely initial pH (2-10), oxidant dosage (5-85 mg/g TSS), and Fe2+ to oxidant ratio (0.2-2) and disintegration time (20-100 min). According to ANOVA results, determination coefficient (R2) was found 93.2%, 76.3%, 84% and 84.8% for each oxidant, respectively. Under the optimum operating conditions, disintegration degree in terms of chemical oxygen demand (DDCOD) was calculated 11.09%, 5.23%, 10.75%, and 5.34%, respectively. Furthermore, bound water reduction (BWR) of waste sludge increased after the disintegration process, and 33.52%, 24.56%, 44.63% and 32.80% BWR values were obtained under the same operating conditions. Results show that the higher DDCOD and BWR values were achieved by calcium hypochlorite and peroxymonosulfate treatment. [ABSTRACT FROM AUTHOR]

The recovery of valuable metals from different types of wastes has become of prime strategic interest given the scarcity of primary critical raw materials at international scale. Implementation of new methods or refinement of classical techniques with modern technological advances is, therefore, an active research field. Mine wastes are of special interest because their high metal concentrations make them environmentally harmful and economically profitable at the same time. In this study, we evaluated two different methods of Cu recovery from extremely acidic mine waters seeping from wastes and abandoned mines in SW Spain. Through a series of different batch experiments, we compared the method efficiency and crystallographic properties of elemental copper (Cu[0]) obtained by reduction of Cu2+ ions by (1) chemical reduction using ascorbic acid at different environmental conditions of pH (1.50–3.95), temperature (25–80 °C) and ascorbic acid concentration (10 mM to 0.1 M), and (2) classical cementation method with scrap iron at pH 1.50 and 25 °C. Our study demonstrates that the precipitation of Cu[0] can take place at pH 3.95 and low AA concentrations (0.1 M), resulting in large (µm-scale), perfectly developed crystals of copper with pseudoprismatic to acicular habit after 24 h of aging, likely through formation of a transient compound consisting in Cu2+-ascorbate and/or cuprite (Cu2O) nanocolloids. Reduction experiments at higher AA concentrations (0.1 M) showed faster precipitation kinetics and resulted in high-purity (>98%) copper suspensions formed by subrounded nanoparticles. The AA method, however, yielded very low recovery rates (15–25%) because of the low pH values considered. The cementation method, which produced tree-like aggregates formed by sub-micron crystals arranged in different directions, proved to be much more efficient (>98% recovery) and cost-effective. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electrochemical ammonia synthesis. • Vibration structure of nitrogenase protein. • Outlook on ammonia economy. The 100th anniversary of a leading nitrogen fixation technology developer like CASALE SA is a reason to reflect over the 20th century successful solution of the problem of world food supply, and to look out for solutions for sustainable developments with respect to ammonia production. We review the role of nitrogen as essential chemical constituent in photosynthesis and biology, and component of ammonia as it is used as fertilizer for primary production by photosynthesis for farming and food supply and its future role as energy carrier. While novel synthesis methods and very advanced synchrotron based x-ray analytical techniques are being developed, we feel it is important to refer to the historical and economical context of nitrogen. The breaking of the N N triple bond remains a fundamental chemical and energetic problem in this context. We review the electrochemical ammonia synthesis as an energetically and environmentally benign method. Two relatively novel X-ray spectroscopy methods, which are relevant for the molecular understanding of the catalysts and biocatalysts, i.e. soft X-ray absorption spectroscopy and nuclear resonant vibration spectroscopy are presented. We illustrate the perceived reality in fertilizer usage on the field, and fertilizer production in the factory complex with photos and thus provide a contrast to the academic view of the molecular process of ammonia function and production. [ABSTRACT FROM AUTHOR]

Silver-decorated reduced graphene oxide (Ag@rGO) nanocomposite was synthesized via a facile chemical reduction method, and its morphology, functional groups, structure, optical and electrical characteristics were investigated. Large distributions of spherical Ag nanoparticles with particle size ranging from 108 to 126 nm anchored into rGO sheets were observed. The energy dispersive X-ray confirms the presence of carbon, oxygen and silver elements in the Ag@rGO nanocomposite. Fourier-transform infrared spectrum exhibited stretching vibrations due to C=O, C–H2, C–O, C=C, O–H and Ag–O bonds in Ag@rGO nanocomposite. X-ray diffraction results of Ag@rGO nanocomposite confirm the formation of rGO and metallic Ag nanoparticles exhibiting FCC structure. The bandgap and ID/IG values of Ag@rGO nanocomposite were obtained as 2.76 and 1.49 eV respectively. Moreover, the study of electrochemical properties of Ag@rGO nanocomposite was carried out, where the maximum specific capacitance of 717.3 and 433.05 F g−1 was achieved at 5 mV s−1 scan rate and 1 A g−1 current density. Moreover, the impedance spectroscopy study exhibited the charge transfer resistance (RCT) value as 6.98 and 71.29 Ω from the Nyquist and Bode plots. I–V characteristics curve shows that the addition of Ag into rGO increases its electrical conductivity. Thus, the results of Ag@rGO nanocomposite can be suitable for supercapacitor application. [ABSTRACT FROM AUTHOR]

[Display omitted] Nickel oxyhydroxide (NiOOH) is regarded as one of the promising cocatalysts to enhance the catalytic performance of photoanodes but suffers from serious interfacial charge-carrier recombination at the photoanode||NiOOH interface. In this work, surface-engineered BiVO 4 photoanodes are fabricated by sandwiching an oxygen vacancy (O vac) interlayer between BiVO 4 and NiOOH. The surface O vac interlayer is introduced on BiVO 4 by a chemical reduction treatment using a mild reducing agent, sodium hypophosphite. The induced O vac can alleviate the interfacial charge-carrier recombination at the BiVO4||NiOOH junction, resulting in efficient charge separation and transfer efficiencies, while an outer NiOOH layer is coated to prevent the O vac layer from degradation. As a result, the as-prepared NiOOH-P-BiVO 4 photoanode exhibits a high photocurrent density of 3.2 mA cm−2 at 1.23 V vs. RHE under the irradiation of 100 mW/cm2 AM 1.5G simulated sunlight, in comparison to those of bare BiVO 4 , P-BiVO 4, and NiOOH-BiVO 4 photoanodes (1.1, 2.1 and 2.3 mA cm−2, respectively). In addition to the superior photoactivity, the 5-h amperometric measurements illustrate improved stability of the surface-engineered NiOOH-P-BiVO 4 photoanode. Our work showcases the feasibility of combining cocatalysts with O vac , for improved photoactivity and stability of photoelectrodes. [ABSTRACT FROM AUTHOR]

[Display omitted] • OMNs Pt-Ru-Ir catalyst shows improved oxygen bifunctional electrocatalysis. • Superior ORR activity (0.21 mA/µg & 0.33 mA/cm2) with extended durability was found. • Excellent OER activity with low Tafel slope and enhanced durability obtained for Pt 70 Ru 25 Ir 5. • Synergistic and mesoporous morphology with trace Ir boosting the bifunctional oxygen kinetics. An efficient oxygen bifunctional catalyst Pt-Ru-Ir with ordered mesoporous nanostructures (OMNs) was successfully synthesized by chemical reduction using KIT-6 mesoporous silica as a template. The crystallographic behavior, electronic effects, and microstructure of the catalysts were investigated by XRD, XPS, SEM, and TEM analysis. The influence of OMNs and the effect of Ir content in Pt-Ru-Ir catalyst on both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) were investigated. The synergistic and electronic effects play an important role in electrocatalytic performance through the electronic coupling between Pt, Ru and Ir followed by the alloy formation with different lattice strain percentages. Amongst, the OMNs Pt 70 Ru 25 Ir 5 catalyst exhibits the highest mass activity of 0.21 mA µg−1 and specific activity of 0.33 mA cm−2 for ORR, which are nearly 5-fold greater than those for benchmark Pt/C catalyst. Furthermore, the Pt 70 Ru 25 Ir 5 demonstrated enhanced OER activity with an overpotential of 470 mV at 10 mA cm−2, an onset potential of 1.70 V, and a Tafel slope of 118 mV dec-1, outperforming commercial IrO 2. In addition, the durability of the Pt 70 Ru 25 Ir 5 catalyst for ORR and OER are found to be extended in comparison with that of other catalysts reported in this work after 6000 cycles. These results demonstrate that the ordered OMNs Pt-Ru-Ir with low Ir content (∼5 wt%) could be a promising oxygen bifunctional catalyst for electrochemical energy conversion and storage applications. [ABSTRACT FROM AUTHOR]

Gypsum plaster is used in linings, coatings, decorative elements, and sealing and is a component of drywall. However, it is susceptible to the development of mold and other microorganisms, especially in hot and humid environments with poor ventilation and sunshine. In order to provide antimicrobial activity to the gypsum, zinc oxide nanoparticles (ZnO-NPs) were added to its matrix. Two types of ZnO-NPs were synthesized, by simple precipitation of sulfate heptahydrate (ZnSO4.7H2O) by sodium hydroxide (NaOH) and with the use of lauryl sulfate, resulting in nanoparticles with a diameter ~ 40 nm. The antimicrobial activity was assessed by the microdilution technique for determination of minimum inhibitory concentration against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Aspergillus niger. SEM images and the count of CFU present in the Staphylococcus aureus biofilm in the specimens composed of reference gypsum and with 15% ZnO-NPs of both syntheses show the efficacy of ZnO-NPs in the gypsum matrix against biofilm (p < 0.05). The specimens with ZnO-NPs also did not allow the proliferation of Aspergillus niger. Therefore, this new material, by preventing the proliferation of these microorganisms, will benefit the health of its users as well as the environment, due to the reduction in the use of chemicals to clean it. Consequently, bringing economic and environmental benefits. [ABSTRACT FROM AUTHOR]

Heavy oil is an important part of petroleum hydrocarbon energy. With the depletion of conventional crude oil reserves, successful and efficient exploitation of heavy oil resources is becoming increasingly important. This article focuses on the nine relatively mature heavy oil development technologies from the perspectives of the level of understanding of the mechanism and the scale of the mining field: steam huff and puff, steam flooding, steam-assisted gravity drainage (SAGD), in situ combustion, thermochemical combined flooding, multicomponent thermal fluid, polymer flooding, chemical viscosity reduction development, and microbial oil recovery, which are divided into two technical categories: thermal recovery and cold recovery development. The basic development principles are explained, and application examples of the two categories of techniques are provided. It is pointed out that thermal compounding, cold mining development, and nanomaterial applications will be the three development trends in heavy oil development. [ABSTRACT FROM AUTHOR]

Palladium–bismuth oxoiodide nanocomposites of various molar ratios of Pd and BiOI have been synthesized by the facile solvothermal method following the chemical reduction technique. The as-synthesized particles have been characterized by X-ray diffraction, spectrophotometric and microscopic studies. All the electrodes made of different Pd–BiOI nanocomposites show improved catalytic performance with synergistic effects for the oxidation of methanol in comparison with the pure components, Pd and BiOI. The modified graphite electrode containing a thin layer of Pd–BiOI composite having 10 mol% of Pd, designated as PB10, has shown the best electrocatalytic performance in comparison with other electrodes for methanol oxidation. The current density using PB10 is increased by 5.4 times with respect to Pd which is further improved by 6.4 times in the presence of visible light for methanol oxidation reaction. The retention of peak current at the 200th cycle of voltammetric operation is found to be 99.5% indicating significant stability of the electrodes. The study essentially suggests PB10 can be used as an efficient anode catalyst for oxidation of methanol in alkali. [ABSTRACT FROM AUTHOR]

This paper examines processes for the preparation of metallic iridium nanoparticles under hydrothermal conditions. The reduction of aqueous potassium hexachloroiridate(IV) solutions with sodium tetrahydridoborate in acidic and alkaline media at temperatures from 130 to 180°C has been shown to take 2–30 min and result in the formation of fine metallic iridium powder with a characteristic mosaic structure. The average size of the iridium(0) nanoparticles varies from 8 to 300 nm, depending on synthesis conditions, and the crystallite size is no greater than 10 nm. According to low-temperature nitrogen gas adsorption measurements, the specific surface area of the materials prepared in acid solutions ranges from 1 to 10 m2/g, and that of the materials prepared in alkaline solutions reaches 25 m2/g. X-ray photoelectron spectroscopy results demonstrate that the surface of the 8-nm-diameter iridium nanoparticles is covered with an oxide film. As shown by differential scanning calorimetry and thermogravimetry in an argon atmosphere, the fraction of iridium oxide compounds in the material with a specific surface area of 25 m2/g does not exceed 5 wt %. [ABSTRACT FROM AUTHOR]