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Highly ordered flower-like mesoporous NiO microspheres with a flower size of ∼2–5 μm and nanoflake size of ∼10–100 nm have been successfully synthesized via a chemical precipitation method assisted by hydrothermal treatment, using nickel acetate tetrahydrate as a metal source, ammonium hydroxide as a base, and diethanolamine (DEA) as a complexing agent. A Ni(OH)2 precursor was prepared with and without cetyltrimethylammonium bromide (CTAB) as a structure directing agent to investigate its effect on the size and morphology of the NiO particles. The physicochemical properties of the obtained NiO nanoparticles (NPs) were characterized using scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), thermogravimetric and differential thermal analyses (TGA/DTA), Fourier-transform infrared (FT-IR) and diffuse reflectance ultraviolet visible (DR UV-vis) spectroscopies, and Brunauer–Emmett–Teller (BET) analysis. The results show that the obtained NiO NPs have a highly ordered nanostructure, with a moderate surface area of 21 m2 g−1, and a pore size of ∼6 nm. SEM, TGA/DTA and PXRD analysis indicate that CTAB is involved in the synthesis process and reduced the Ni(OH)2 size from 2 to 5 μm without having any significant effects on the particle morphology. The photocatalytic performance of NiO NPs was investigated under the illumination of UV light in the decolourization reaction of methyl green dye in aqueous solution. The NiO NPs exhibit excellent dispersion in the dye solution and considerable photocatalytic activity with a rate constant that is almost ten times higher than that of bulk NiO NPs. [ABSTRACT FROM AUTHOR]

In this study, the visible light active pristine, binary and ternary g-C 3 N 4 /CdS/CuFe 2 O 4 nanocomposite is prepared through a coprecipitation-assisted hydrothermal technique. The characterization of the as-synthesized catalysts was conducted using various analytical techniques. When compared with pristine and binary nanocomposites, the ternary g-C 3 N 4 /CdS/CuFe 2 O 4 nanocomposite exhibits higher photocatalytic degradation of azithromycin (AZ) under a visible light source. Ternary nanocomposite exhibits high AZ removal efficiency of about 85% within 90 min of the photocatalytic degradation experiment. Enhanced the visible light absorption ability and the suppression of photoexcited charge carriers is also achieved by forming heterojunctions between pristine materials. The ternary nanocomposite exhibited ∼2 times higher degradation efficiency than CdS/CuFe 2 O 4 nanoparticles and ∼3 times higher degradation efficiency than CuFe 2 O 4. The trapping experiments were conducted and it shows superoxide radicals (O 2 •-) are the predominant reactive species involved in the photocatalytic degradation reaction. This study provided a promising approach for the treatment of contaminated water using g-C 3 N 4 /CdS/CuFe 2 O 4 as a photocatalyst. [Display omitted] • g-C 3 N 4 /CdS/CuFe 2 O 4 nanocomposite is prepared through a coprecipitation-assisted hydrothermal technique. • Ternary nanocomposite exhibits higher photocatalytic degradation of azithromycin (AZ) under a visible light source. • Addition of Peroxydisulfate enhanced the photocatalytic efficiency which shows the involvement of SO 4.•- radicals in the degradation reaction. • Highly stable nature of the prepared ternary photocatalyst even after 5 cycles of photocatalytic degradation reaction. [ABSTRACT FROM AUTHOR]

Copper ferrite (CuFe2O4) nanoparticles were prepared using the sol-gel autocombustion method and then coated with phosphate using different treatments with H3PO4. The structural and chemical properties of the phosphate-coated CuFe2O4 nanoparticles were controlled by changing the concentration of H3PO4 during the coating process. The prepared nanoparticles were characterized using XRD, FTIR, SEM, and EDS which provided information about the catalysts' structure, chemical composition, purity, and morphology. The catalytic and photocatalytic activities of the phosphate-coated CuFe2O4 samples were tested and evaluated for the degradation of phenol using HPLC. The prepared nanoparticles successfully emerged as excellent heterogeneous Fenton-type catalysts for phenol degradation. The phosphate-coated CuFe2O4 catalysts exhibited a higher catalytic activity compared with the uncoated CuFe2O4 ones. Such a higher catalytic performance can be attributed to enhanced morphological, electronic, and chemical properties of the phosphate-coated CuFe2O4 nanoparticles. Additionally, the phosphate-coated CuFe2O4 nanoparticles also revealed a higher catalytic activity compared with TiO2 nanoparticles. Different experimental conditions were investigated, and complete removal of phenol was achieved under specific conditions. [ABSTRACT FROM AUTHOR]

Colloidal gas aphrons (CGAs) are highly stable, spherical, micrometer-sized bubbles encapsulated by surfactant multilayers. They have several intriguing properties, including: high stability, large interfacial area, and the ability to maintain the same charge as their parent molecules. The physical properties of CGAs make them ideal for biotechnological applications such as the recovery of a variety of: biomolecules, particularly proteins, yeast, enzymes, and microalgae. In this review, the bio-application of CGAs for the recovery of natural components is presented, as well as: experimental results, technical challenges, and critical research directions for the future. Experimental results from the literature showed that the recovery of biomolecules was mainly determined by electrostatic or hydrophobic interactions between polyphenols and proteins (lysozyme, β-casein, β-lactoglobulin, etc.), yeast, biological molecules (gallic acid and norbixin), and microalgae with CGAs. Knowledge transfer is essential for commercializing CGA-based bio-product recovery, which will be recognized as a viable technology in the future. [ABSTRACT FROM AUTHOR]

Sepiolite clay was used as an adsorbent for the removal of iron ions from industrial methyldiethanolamine (MDEA) solvent. The raw sepiolite clay was modified by different chemical and thermal treatments, and was characterized by FTIR, XRD, SEM-EDX, and BET-specific surface area analysis. Treating sepiolite with nitric acid significantly improved the adsorption capacity of iron ions from lean MDEA. The experimental equilibrium data were represented by Henry, Freundlich, and Langmuir isotherm models. The thermodynamic parameters indicated that the adsorption of iron ions on sepiolite was spontaneous and endothermic process. The kinetic studies showed that the adsorption followed pseudo-second order model. [ABSTRACT FROM AUTHOR]

We investigate HS gas sensors based on spinel ferrite CuFeO nanoparticles prepared by the co-precipitation method. This technique is an efficient and fast technique to produce nanoparticles. Furthermore, those nanoparticles are metal-oxide nanoparticles with magnetic properties that enable their retrieval and reuse for mutable times and applications. The produced nanoparticles are pressed in a form of disc, and placed between two electrical electrodes, with the top electrode with a grid structure to enable gas exposure. The study includes investigations of crystal structure, composition, morphology, and charge transport. The results revel that the produced nanoparticles are sensitive and selective to HS which indicate their potential to be used for practical applications. [ABSTRACT FROM AUTHOR]

The environmentally friendly nature of natural cellulose, as well as its excellent crystallinity and mechanical properties, have piqued researchers' interest. In this study, date palm seeds as agricultural waste generated abundantly every year in the Gulf region were used as a raw material to extract crystalline nanocellulose. Dewaxing, alkali treatment, bleaching, and acid hydrolysis were used in a stepwise treatment approach to remove nanocellulose from seeds. The amorphous phase of the biopolymer had been successfully removed, according to the FT-IR analysis of the obtained cellulose. Sodium chlorite bleaching provided the highest degree of crystallinity, with a crystallinity index of 72.49%. The nanocellulose exhibited a bimodal distribution at 43–78 nm and 190-458 nm using particle size analysis. An agglomerated and irregular semi-spherical crystalline cellulose structure was revealed by SEM analysis. Nano spheres of 20–100 nm dispersed within the amorphous matrix of the cellulose was observed in one of the samples using TEM analysis. The extractable crystalline cellulose displayed good thermal stability. Date-derived crystalline nanocellulose has promising properties and could be used in several industrial and domestic applications. [ABSTRACT FROM AUTHOR]

The adsorption of carbon monoxide (CO), propane (C3H8) and propene (C3H6) on V2O3(0001) films grown on Au(111) was studied by Temperature Programmed Desorption (TPD) and X-ray Photoelectron Spectroscopy (XPS). The “oxidized” surface (i.e., as prepared exhibiting V=O termination), the “reduced” surface (i.e., V=O groups being removed by electron irradiation), as well as the oxygen pre-covered reduced surface were investigated. Both TPD and XPS indicate that the oxidized surface has little affinity for CO adsorption, while the reduced surface readily binds CO (CO amount approx. 10 times higher). Accordingly, CO can be used to titrate the presence or absence of vanadyl oxygen (via adsorption on the vanadium atoms) but also of defects like surface oxygen vacancies. For propane and propene, desorption of the parent molecules was the major process, i.e., surface reactions were absent under the applied conditions. When oxygen was pre-adsorbed on the reduced surface, the adsorption properties resembled that of the oxidized surface, i.e., the vanadyl groups were (partially) re-established. TPD and XPS provide a handle to differentiate the binding sites on the V2O3 surface. [ABSTRACT FROM AUTHOR]

Palladium nanoparticles (Pd NPs) have attracted considerable attention recently for their excellent catalytic properties in various catalysis reactions. However, Pd NPs have some drawbacks, including their high cost, susceptibility to deactivation, and the possibility of poisoning by intermediate products. Herein, Pd nanoparticles with an average diameter of 6.5 nm were successfully incorporated on electronically transparent 2D MXene (Ti3C2Tix) nanosheets (Pd-MXene) by microwave irradiation. Considering the synergetic effects of ultra-fine Pd NPs, together with the intrinsic properties of 2D MXene, the obtained Pd-MXene showed a specific surface area of 97.5 m2g−1 and multiple pore channels that enabled excellent electrocatalytic activity for the reduction of CO2. Further, the 2D Pd-MXene hybrid nanocatalyst enables selective electroreduction of CO2 into selective production of CH3OH in ambient conditions by multiple electron transfer. A detailed explanation of the CO2RR mechanism is presented, and the faradic efficiency (FE) of CH3OH is tuned by varying the cell potential. Recyclability studies were conducted to demonstrate the practical application of CO2 reduction into selective production of CH3OH. In this study, metal and MXene interfaces were created to achieve a highly selective electroreduction of CO2 into fuels and other value-added chemical products. [ABSTRACT FROM AUTHOR]

A facile low-temperature approach was employed to prepare CuFe 2 O 4 nanoparticles over chemically reduced graphene oxide (CuFe 2 O 4 /rGO) by co-precipitation of rGO with copper and iron salts in one-pot. The structures, compositions, purities, and morphologies of CuFe 2 O 4 /rGO composites were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques. The results showed that CuFe 2 O 4 nanoparticles decorated uniformly the rGO sheets. The prepared CuFe 2 O 4 /rGO composites were applied as heterogeneous Fenton-like catalysts for the degradation of phenol, as a model pollutant, using high-performance liquid chromatography (HPLC). The photocatalytic activity of the CuFe 2 O 4 /rGO composites was also investigated. Complete removal of phenol was achieved within 15 min under photocatalytic conditions at room temperature. The CuFe 2 O 4 /rGO nanocomposites exhibited a higher catalytic activity compared to bare CuFe 2 O 4 nanoparticles. The catalytic performance of CuFe 2 O 4 /rGO was also higher than TiO 2 catalysts. Image 109 • CuFe 2 O 4 /rGO composites were prepared by a facile low-temperature approach. • CuFe 2 O 4 nanoparticles decorated uniformly the rGO sheets. • The composites exhibited high catalytic activity for the degradation of phenol. • Complete removal of phenol was achieved within 15 min under photocatalytic conditions at room temperature. [ABSTRACT FROM AUTHOR]

In this study, a graphene–sand hybrid (GSH) was successfully synthesized from locally available desert sand and sugar using a green chemistry approach and used as an adsorbent for the removal of dissolved sulfides from aqueous solutions. The structure, composition, and morphology of the new GSH adsorbent were characterized in detail by Raman spectroscopy, scanning electron microscopy equipped with energy dispersive X-ray spectroscopy, zeta potential and Fourier-transform infrared spectroscopy. Batch experiments were conducted to evaluate the effect of several process parameters such as contact time, pH, adsorbent dosage and ionic strength on the removal of sulfide using the GSH adsorbent. These results indicated that GSH exhibited good sulfide removal capacity from aqueous solutions with a maximum uptake capacity of 370 mg g−1, so far the highest value reported in the literature. Langmuir and pseudo-second order models well fitted the equilibrium and kinetic data, respectively. Comparison of linear and non-linear regression methods for the adsorption isotherms revealed that a non-linear model was a better way to obtain the isotherm parameters. The spectroscopic and microscopic and thermogravimetric analysis demonstrated that chemical interaction with oxygen rich functional groups played a major role in adsorption, resulting in the formation of elemental sulfur and sulfates as byproducts. The obtained results illustrated that the prepared graphenic material is an effective, environmentally friendly and economically viable adsorbent for removing toxic and malodorous sulfide ions from aqueous solutions. [ABSTRACT FROM AUTHOR]

Owing to increase in cost and low availability of Li source causes the high rate of the energy storage devices. By focusing on these issues, the cost effective and high performed electrode is needed for energy storage application. Na based electrodes can replace the Li ion batteries because of the availability of Na is higher than the Li. The cost of the energy storage devices can be reduced by using Na instead of Li. Many other electrodes are reported based on Na ion batteries. Since in this present work we prepared O3–NaFeO 2 (NIO) high performance electrode prepared by two step hydrothermal assisted solid-state method. But the battery performance of NaFeO2 is suffers from capacity decay during long term cycling. For these issues naturally derived sucrose from the sugarcane is prepared which increase the electrochemical performance of Ac carbon coated NaFeO 2 (AC Coated NIO). The AC Coated NIO electrode delivers the capacity of about 131 mAh g−1 at 80 mA g−1. The retention capacity of material is about 92% after 100 cycles. Such electrochemical action of the current electrode can show the way to cost effective and highly performed Na ion electrode development for Energy storage devices. [ABSTRACT FROM AUTHOR]

Porous magnetite (Fe3O4) and hematite (α-Fe2O3) nanoparticles were prepared via the sol-gel auto-combustion method. The gels were prepared by reacting ferric nitrates (as oxidants) with starch (as fuel) at an elevated temperature of 200 °C. Different ratios (Φ) of ferric nitrates to starch were used for the synthesis (Φ = fuel/oxidant). The synthesized iron oxides were characterized by Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, X-ray diffraction (XRD) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmet-Teller (BET) and vibrating sample magnetometer (VSM) analysis techniques. The crystal structure, morphology, and specific surface area of the iron oxide nanoparticles (Fe3O4 and α-Fe2O3) were found to be dependent on the starch content. The FT-IR, XRD and VSM analysis of the iron oxides for Φ = 0.3 and 0.7 confirmed the formation of the α-Fe2O3 core, whereas at Φ = 1, 1.7, and 2 showed that Fe3O4 cores were formed with the highest saturation magnetization of 60.36 emu/g at Φ = 1. The morphology of the Fe3O4 nanoparticles exhibited a quasi-spherical shape, while α-Fe2O3 nanoparticles appeared polygonal and formed clusters. The highest specific surface area was found to be 48 m² g-1 for Φ = 1.7 owing to the rapid thermal decomposition process. Type II and type III isotherms indicated mesoporous structures. [ABSTRACT FROM AUTHOR]

Nowadays, cobalt-based catalysts are becoming increasingly attractive for various reactions. In this work, the catalytic and photocatalytic activities of different cobalt ferrites were investigated for the degradation of phenol in water at neutral pH. Pure CoFe 2 O 4 and mixed Co x Ni 1-x Fe 2 O 4 ferrites were synthesized using different precursors (chloride and nitrate). CoFe 2 O 4 catalysts derived from chloride precursors showed a higher catalytic efficiency compared to those derived from nitrate precursors. Significant enhancement in the catalytic activities was observed when Ni was incorporated into CoFe 2 O 4. Furthermore, the catalytic activities of phosphorus-modified cobalt ferrites (P-CoFe 2 O 4) significantly improved the photocatalytic degradation of phenol. Unlabelled Image • CoFe 2 O 4 nanoparticles exhibited different morphological features and catalytic properties. • Nitrate-derived CoFe 2 O 4 catalysts were inactive, while chloride-derived catalysts were active. • Mixed Co x Ni 1-x Fe 2 O 4 ferrites with showed significant enhancements in the catalytic activities. • For the first time, P-CoFe 2 O 4 were synthesized and tested for the catalytic degradation of phenol. [ABSTRACT FROM AUTHOR]

Phosphorus-modified copper ferrite (P–CuFe 2 O 4) nanoparticles were prepared by a simple sol-gel auto-combustion process and used for the photocatalytic ozonation of lomefloxacin (LOM). The morphology, crystallinity, and structure of the synthesized CuFe 2 O 4 and P–CuFe 2 O 4 nanoparticles were investigated using various techniques. The high-performance liquid chromatography (HPLC) analysis revealed that the degradation of LOM achieved a 99% reduction after a duration of 90 min in the photocatalytic ozonation system. In accordance with the charge-to-mass ratio, four intermediates were proposed with the help of their fragments obtained in LC–MS/MS. The degradation kinetics of lomefloxacin followed a pseudo-first order reaction, and the degradation mechanism was proposed based on the results. P 0.035 Cu 0.965 Fe 2 O 4 showed the highest total organic carbon (TOC) removal with 20.15% in 90 min, highest specific surface area and the highest fluoride and ammonium production using the ion chromatography (IC). The experimental results obtained from the electron paramagnetic resonance (EPR) analysis indicated that the modified P–CuFe 2 O 4 samples exhibited significantly elevated levels of superoxide (. O 2 −) production compared to the CuFe 2 O 4 samples. The findings of this study demonstrate that the introduction of phosphorus modification into the copper ferrite photocatalyst led to an augmentation of both the specific surface area and the total pore volume. Furthermore, the incorporation of phosphorus served to promote the efficient separation of electron-hole pairs by effectively trapping electrons in the conduction band, hence enhancing the degradation efficiency. [Display omitted] • Phosphorus Modified Copper Ferrite (P–CuFe 2 O 4) nanoparticles were successfully synthesized using a sol-gel auto-combustion method. • Phosphorus modification showed interesting improvements over parent materials. • Photocatalytic ozonation exhibited higher efficiency than the photolysis process for the degradation of lomefloxacin. • Ions F− and NH 4 + were found and gradually built up during the reaction. [ABSTRACT FROM AUTHOR]

• Cerium vanadate nanostructures was prepared by simple one-pot co-precipitation method. • The nanostructures resulted in complete degradation of 100 ppm phenol in 80 min via activation of PMS. • The degradation followed a pseudo-first-order kinetics model with high R2 value and low activation energy of 23.74 kJ/mol. • The nanostructures were tested for recyclability up to 5 cycles and displayed excellent recyclability and reusability. • The mechanistic study revealed that non radical pathway via 1O 2 mediated activation of PMS govern the catalytic activity. In this study, a nanostructured CeVO 4 material was synthesized using a simple co-precipitation technique and investigated as a catalyst for phenol degradation via peroxymonosulfate (PMS) activation. The structural and morphological properties of the CeVO 4 catalyst were characterized using XRD, XPS, FTIR, Raman spectroscopy, TGA, SEM, and TEM. The results indicated that the prepared catalyst exhibited a pure crystalline phase with a rod-like structure. The CeVO 4 catalyst exhibited high activity towards PMS activation, resulting in complete degradation of phenol within the first 80 min at room temperature. The degradation reaction was found to follow pseudo-first-order kinetics with a low activation energy of 23.74 kJ/mol. The degradation followed a catalytic surface-mediated electron transfer route as confirmed using ESR measurements. The effects of several experimental parameters on phenol degradation were investigated, including the catalyst loading, initial phenol concentration, PMS dosage, reaction temperature, and pH. The regeneration and reusability of the CeVO 4 catalyst were also examined for 5 consecutive cycles. This study puts forward CeVO 4 as a heterogeneous catalyst for the complete removal of persistent organic pollutants via PMS activation, indicating a favorable application in wastewater treatment. [ABSTRACT FROM AUTHOR]

Calcium alginate hydrogel was grafted with poly (styrene-co-maleic anhydride) synthetic polymer (PSMA) and used as an adsorbent for the effective removal of methyl violet 6B cationic dye from aqueous solutions. The characteristics of native and grafted alginate hydrogels were investigated using FTIR, Zetasizer and TGA/DSC. The carboxyl groups' content and the swelling properties were determined as well. Batch adsorption experiments were conducted as a function of initial dye concentration, adsorbent dosage, solution ionic strength, solution pH, time of contact and temperature. Results revealed that grafting of PSMA onto alginate improved the removal percentage of the dye up to 30%. The highest adsorption capacity of the dye was obtained at a temperature of 40 °C, a pH range of 5-11 and at lower solution ionic strengths. The kinetics of adsorption followed the pseudo-second-order model and the equilibrium data could be better described by the Langmuir isotherm. The maximum adsorption capacity was found to be 109.9 mg/g suggesting the promising potential of our low-cost adsorbent for the removal of cationic dyes from aqueous solutions. A desorption study was carried out where the adsorbent showed high desorption characteristics and it could be reused at least for five consecutive cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Conversion of N 2 into ammonia is highly desirable for sustainable energy production. • The Au-WS 2 @RGO photoelectrode is more efficient at converting N 2 to ammonia. • The detailed mechanism of PEC reduction of N 2 to NH 3 is investigated using DFT. • Au-WS 2 @RGO exhibits the highest NRR performance among state-of-the-art NRR catalysts. The photoelectrochemical reduction of nitrogen to ammonia (NH 3) is a sustainable and cost-effective process. The photoelectrocatalysts adsorb light, activate N 2 , and transport electrons efficiently to achieve high-yield NH 3. In the present work, gold-tungsten sulfide-anchored reduced graphene oxides (Au-WS 2 @RGO) are developed as highly efficient photoelectrocatalysts for the N 2 reduction reaction (NRR) to synthesize NH 3. The effect of Au nanoparticles loaded on WS 2 @RGO is optimized to achieve hierarchical 2D Au-WS 2 @RGO with excellent electrical conductivity, large active surface area, and unique porous network. Photoelectrocatalytic NRR of Au-WS 2 @RGO achieves remarkable NH 3 production rates with ultrahigh NH 3 yield of 34 μgh-1mg cat -1 at −0.6 V, tremendous faradaic efficiency (FE) of 16.2 %, long durability for about 14 h, and prolonged lifetime of photo-carriers. DFT calculations support the experimental findings and demonstrate that Au-WS 2 @RGO as an effeient NRR catalyst with low overpotential. The Au-WS 2 @RGO shows the highest NRR performances even in atmospheric air (AirRR) and outperforms the state-of-the-art NRR catalysts. The high AirRR performance and durability of Au-WS 2 @RGO make it a promising alternative to Au-based NRR catalysts in photo electrolyzers. Further, an innovative methodology will be proposed for high-efficiency urea fertilizer production using Au-WS 2 @RGO-based NRR photocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanohybrids of 2D Au-WS 2 were used to fabricate an efficient bifunctional electrode. • A 2D Au-WS 2 photoanode is employed for the PEC oxidation of phenol. • PEC oxidation of phenol and As(III) over a 2D Au-WS 2 photoanode was investigated simultaneously. • The PEC system removes organic and inorganic pollutants from wastewater. Two dimensional (2D) photoelectrocatalysts with a tunable band gap and a large surface area have emerged in recent years for advanced oxidation processes that remove toxic compounds from wastewater. In this study, ultra-thin 2D tungsten sulfide (2D WS 2) photoelectrocatalysts have been fabricated using organosulfur sources, and the resulting 2D WS 2 has high chemical stability and visible light band edges. Additionally, citrate stabilized Au nanodots were successfully incorporated into the 2D WS 2 nanosheets in order to reduces the charge carrier recombination. The morphology, composition, chemical state, and optical properties of the Au-WS 2 photoanodes have been systematically investigated. An Au-WS 2 photoanode is successfully assembled in a photoelectrochemical cell (PEC) for removing phenol and oxidizing toxic As(III) into non-toxic As(V) under visible light. The studies show that the Au-WS 2 photoanode had an oxidation efficiency of 99% for phenol and 95% for As(III) under visible light illumination. Furthermore, X-ray photoelectron spectroscopy (XPS) and theoretical analyses were used to investigate the oxidation pathways of phenol and As(III). A reachability study was carried out to demonstrate that mixed synthetic wastewater containing phenol and arsenite could be used for extended periods in a practical manner. In this study, Au-WS 2 photoanodes were demonstrated to be highly effective in enhancing environmental remediation using advanced oxidation methods. [ABSTRACT FROM AUTHOR]

Rapid urbanization and industrial development has led to increased discharge of wastewater from process plants such as oil and gas refineries in recent years. Refinery wastewater is a complex mixture of various organic and inorganic compounds. Due to their toxicity and increased generation volume, environmentally accepted disposal of oily wastewater is a current challenge to the petroleum industry worldwide. Besides, stringent global standards have necessitated new and existing facilities to achieve higher levels in wastewater treatment to recover more water for re-use. Compared to different physical and chemical methods employed in effluent treatment, biological processes are considered to be environment-friendly, benign, profitable and cost effective. In this review, the source, characteristics and toxicity impact of petroleum refinery wastewater (PRW) is introduced. A comprehensive summary on the recent developments of different biotreatment techniques adopted for PRW refinement, with reference to inorganics and heavy metals have been discussed. Based on observations, it is inferred that no individual process can be considered as a panacea, since each method is outlined by several advantages and limitations. This work aims to help future researchers and practitioners to have a good understanding of the present progress and future perspectives in the field. [ABSTRACT FROM AUTHOR]

The SnO 2 and SnO 2 /rGO nanostructures were successfully synthesized using the facile hydrothermal synthesis technique. The prepared nanostructures were well studied using different techniques such as XRD, XPS, UV-DRS, FT-IR, EDX, SEM and HR-TEM analysis. The crystalline nature of SnO 2 and SnO 2 /rGO was confirmed by the XRD technique. The formation of highly pure SnO 2 and SnO 2 /rGO nanostructures was confirmed by EDX analysis. The morphological results show the good agglomeration of several spherical nanoparticles. The optical properties were studied through the UV-DRS technique and the bandgap energies of SnO 2 and SnO 2 /rGO are estimated to be 3.12 eV and 2.71 eV, respectively. The photocatalytic degradation percentage in presence of SnO 2 and SnO 2 /rGO against RhB was found to be 96% and 98%, respectively. The degradation of TTC molecules was estimated as 90% and 88% with SnO 2 /rGO and SnO 2 , respectively. The degradation of both RhB and TTC molecules was well suited with the pseudo-first-order kinetics. The results of successive experiments clearly show the enhancement in the photocatalytic properties in the SnO 2 /rGO nanostructures. [Display omitted] • SnO 2 and SnO 2 /rGO were successfully synthesized using hydrothermal technique. • Visible light absorption ability of SnO 2 and SGO is confirmed by UV-DRS analysis. • Photocatalytic activity of SnO 2 and SnO 2 /rGO was studied against Rhodamine B and Tetracycline. • Photocatalytic degradation mechanism is proposed based on optical properties and band edge positions. [ABSTRACT FROM AUTHOR]

[Display omitted] • The capture and utilization of CO 2 is crucial for climate change mitigation. • A plasmon-enhanced photoelectrochemical process for CO 2 and N 2 into urea was proposed. • The plasmonic Au nanostructures are tuned to maximize CO 2 and N 2 PEC reduction activity. • A PEC system based on Au nanosheets yielded higher urea (of 98.5 µg urea mg cat -1 h−1) and FE of 22.7% The photoelectrochemical reduction of CO 2 and N 2 (N 2 CO 2 RR) is a promising method of producing urea under ambient conditions since highly active and stable electrocatalysts are desired. Plasmonic metals have attracted considerable attention due to their enhanced electrochemical activity at visible and near-infrared wavelengths (NIR). Herein, the morphology of Au was tuned to spherical nanoparticles, nanorods, and nanosheets by utilizing a variety of structure-directing agents. Among them, Au nanosheets (Au NSs) can absorb a broad spectrum of NIR wavelengths, enabling electrochemical reduction of N 2 into NH 3 , with high yield rates and higher Faradic efficiency (FE) than most of the N 2 RR results reported. In addition, a distal associative pathway for N 2 RR into NH 3 has been established over Au NSs. Additionally, the Au NSs photocathode demonstrates high stability over a period of 10 consecutive runs. In addition, this work provides a guide to fabricating highly stable photocathodes that convert N 2 and CO 2 into urea. Au NSs photocathode achieves a maximum urea yield rate of 98.5 µg urea mg cat -1h−1 and FE of 22.7% at −0.7 V vs. RHE. Results show that the N 2 and CO 2 is the primary factor for urea production, whereas reducing NO 3 – and HCO 3 – contributes significantly to the total urea yield rate. Density functional theory calculations (DFT) reveal that Au NSs play a crucial role in promoting N 2 and CO 2 adsorption, activation, and stimulating the coupling reaction between C-N to form urea by the distal mechanism. As a result, this work opens up the possibility of developing hybrid catalytic systems for simultaneously reducing nitrate-containing wastewater and CO 2 , thus producing urea-rich treated water for agricultural use and achieving carbon neutrality. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel Au/α-Fe 2 O 3 /RGO photocathode and Ru/RGO anode were synthesized and characterized. • Investigated half-cell PEC CO 2 reduction over Au/α-Fe 2 O 3 /RGO photocathode • Results on paired PEC CO 2 reduction efficiency coupled with the anodic oxidation of furfural were presented • Paired PEC electrolyzer enables a cost-effective process for CO 2 reduction and conversion of biomass compounds. The global warming and energy requirement have accentuated the need to convert atmospheric CO 2 into fuels through a highly efficient photoelectrochemical cell (PEC) process. Typically, CO 2 reduction at the cathode is accompanied by water oxidation at the anode to produce O 2 , which is not of significant value. Herein, we report the design of paired PEC to reduce CO 2 to CH 3 OH and the oxidation of furfural (FF) to 2-furoic acid (2-FA) and 5-hydroxyfuroic acid (5-HFA). The paired PEC electrolyzer was constructed with Au/α-Fe 2 O 3 /RGO and Ru/RGO/Pt based asymmetric electrodes. The photocathode-driven PEC CO 2 conversion test showed a high CH 3 OH yield of 63 μmol L−1 cm−2 at 21.5 % quantum efficiency with a Faradaic efficiency of 91 % at -0.6 V under visible light. The anodic furfural oxidation test demonstrated a higher FF conversion (82 %) with higher yields of 2-FA and 5-HFA. This study showed the potential of the paired PEC process to produce valuable products at both electrodes. [ABSTRACT FROM AUTHOR]

• Co, Ni & Co-Ni mixed ferrites were developed as novel CDI electrode materials. • Co 0.5 Ni 0.5 -Fe 2 O 4 showed high specific capacitance of 255 F/g than pure ferrites. • NaCl electrosorption capacity of 21.84 mg/g & good reusability for Co 0.5 Ni 0.5 -Fe 2 O 4. • Co 0.5 Ni 0.5 -Fe 2 O 4 is a potential CDI electrode material for desalination application. Capacitive deionization (CDI) is an emerging technology for water desalination and is based on electrosorption of ions onto surfaces of electrically charged electrodes. The CDI electrode materials play a significant role in determining the process efficiency. In this study, pure and mixed nickel-cobalt ferrites Co x Ni 1-x Fe 2 O 4 (x = 0.0, 0.3, 0.5, 0.7 and 1.0) were synthesized using the sol-gel auto-combustion method and investigated as novel CDI electrode materials. The purity, structure, and morphology of the synthesized ferrite nanoparticles were analyzed by various techniques. The electrochemical performance of the synthesized materials was investigated, and the results showed that the mixed ferrite Co 0.5 Ni 0.5 Fe 2 O 4 electrode possessed the highest specific capacitance of 255 F/g at a scan rate of 10 mV/s. The electrodes were used to treat 250 mg/L NaCl solution in a CDI cell at 1.2 V and a feed flow rate of 10 mL/min. Under optimized experimental conditions, the highest specific salt adsorption capacity was 21.84 mg/g, corresponding to 23.43% of NaCl removal efficiency. These electrodes were highly stable and easily regenerable with less than 5% loss in electrosorption capacity for six adsorption/desorption cycles. The recyclability, stability, and enhanced electrochemical performance of the fabricated electrodes establish cobalt-nickel ferrites as a promising material for use in CDI desalination application. Image, graphical abstract [ABSTRACT FROM AUTHOR]

A green and cost-effective technique for the preparation of silver nanoparticles (Algae-AgNPs) as a colorimetric sensor for hydrogen peroxide (H2O2) is described. Silver nanoparticles were capped using the green algae (Noctiluca scintillans) extract at an optimum time of 3 h at 80 °C. The pH of the plant extract (pH = 7.0) yields nanoparticles with a mean size of 4.13 nm and a zeta potential of 0.200 ± 0.02 mV and negative polarity, using dynamic light scattering (DLS). High-resolution transmission electron microscopy (HRTEM) analysis showed regular spherical particles with the average size of 4.5 nm. Selected area electron diffraction (SAED) results revealed the polycrystalline nature of the silver nanoparticles. The obtained patterns were indexed as (111), (200), (220), and (311) reflections of the fcc (face centered cubic) silver crystal based on their d-spacing of 2.47, 2.13, 1.49, and 1.27 Å, respectively. The apparent color change from brown to colorless was observed when nanoparticles reacted with H2O2. Linear responses were obtained in three different ranges (nM, µM, and mM). Limits of detection (LOD) of 1.33 ± 0.02 and 1.77 ± 0.02 nM and quantitation limits (LOQ) of 7.31 ± 0.03 and 9.67 ± 0.03 nM were obtained for Abs and ΔAbs calibration curves, respectively. 10% v/v Algae-AgNPs solution inhibited Staphylococcus aureus over Escherichia coli, while a 50% reduction of tumor cell growth of MDA-MB-231 human breast adenocarcinoma was obtained. [ABSTRACT FROM AUTHOR]

Renewable biomass waste derived porous carbon materials are widely accepted due to their low cost, eco-friendliness, and sustainability. Herein, a two dimensional (2D) nitrogen (N) -doped porous carbon nanosheets were prepared via a facile and cost-effective pyrolysis method using potassium hydroxide (KOH) activated Tamarind shell biomass waste and urea as the precursors. With the synergetic effect of N-doping, graphitic nature, 2D morphology, hierarchical pores, large specific surface area (410 m2 g−1) and high electrical conductivity, the as-obtained N-doped carbon nanosheets showed many favorable features to be an excellent electrode material for effective capacitive deionization (CDI) process. Furthermore, the presence of nitrogen heteroatom contributes to an increase in polarity of the carbon material, which is crucial for improving the wettability of the electrode in the CDI process. The electrochemical analysis showed that the N-doped carbon nanosheets have a better electrochemical double layer (EDL) characteristic, and it possess a specific capacitance of 174.5 F g−1 in 10 mV s−1 than undoped carbon nanosheets (70.6 F g−1). Besides, in the deionization test, the N-doped carbon nanosheets exhibit a maximum salt adsorption capacity (SAC) of 18.8 mg g−1 in 600 mg L−1 NaCl solution at 1.2 V, which is significantly higher than that of undoped carbon nanosheets (11.1 mg g−1). Thus, N-doping is proposed to be an effective method in not only improving the electrical conductivity and wettability of the carbon but also played a crucial role in enhancing the electrosorption performance. As such, the low-cost biomass waste tamarind shell derived N-doped carbon nanosheets developed in this work present offers a promising electrode material for conventional high-performance symmetric CDI applications. • N-doped porous carbon nanosheets (NTC-800) produced from biomass of tamarind shell • NTC-800 possesses specific capacitance of 174.5 F g−1 at 10 mV s−1 scan rate. • NTC-800 utilized as active electrode material for symmetric CDI application • NTC-800 exhibits salt removal capacity of 18.8 mg g−1 at 600 mg L−1, 1.2 V. • NTC-800 shows good regeneration ability in symmetrical CDI system. [ABSTRACT FROM AUTHOR]