Ratio Of NaOH Research Articles

Optimization and characterization of the ternary blended iron rich natural binder concrete system

Around the world, the infrastructure developmental activities searching for new generation cementing binders. Geopolymer is a hard stratum of non-crystalline inorganic alumino-silicate networks developed by alkali activated industrial by-product materials like fly ash, metakaolin and ground granulated blast furnace slag. Laterite is a natural iron-rich aluminosilicate binder material that could be used as a binder with an essential chemical composition. In this research, optimization of iron rich binder content is used to enhance the compressive strength of concrete. For this, various factors were considered and employed in the Taguchi’s experimental technique. An orthogonal array of L16 (4)5 of four parameter levels and four factors are considered to optimize the iron-rich natural material with metakaolin and GGBFS as ternary blend, the molarity of NaOH solution, Na2SiO3to NaOH ratio, and liquid by binder ratio. The results trials showed strength fluctuating between 16 and 60 N/mm2 and the optimized mix obtained as 65 N/mm2. The optimized samples were undergone material characterization to ensure the transformation of iron source activated compound combinations, and the phase changes using FTIR, XRD, SEM-EDS, DTA, Electron paramagnetic resonance spectroscopy, and Mossbauer Spectroscopy.

A novel design for biodiesel production from methanol + mutton bone fat mixture

Bioenergy plays a significant role in the green transition. In this work, the conversion of methanol and mutton bone fat oil (as a low-cost feedstock) for bioenergy production was studied. The five-level, three-factor response surface methodology (RSM) was used to optimize the transesterification reaction conditions for produced biodiesel. Twenty ultrasonic-assisted experiments at the frequency of 25 kHz were conducted to investigate the effects of methanol/oil molar ratio (M/O) and concentrations of KOH and NaOH as catalysts on biodiesel yield. A second-order polynomial equation was developed by fitting the RSM experimental data using Design-Expert software. Results showed that the optimum biodiesel yield of 90.087% could be achieved by the KOH catalyst with 2.5 wt% concentration and 15:1 M/O during 3 h of the reaction. Furthermore, the biofuel analyses showed that methanol and mutton bone fat oil can be used as a proper feedstock for biofuel production. In the following, a membrane filtration package system is proposed and modeled. The reaction kinetics was determined based on experimental data. The results of the mathematical modeling showed the reaction time appears to be 6 times shorter in a membrane setup (30 min). Consequently, membrane application is highly recommended for biodiesel production from mutton bone fat oil.

Highly-efficient molten NaOH-KOH for organochlorine destruction: Performance and mechanism

Molten salt has been increasingly acknowledged to be useful in the destruction of chlorine-containing organic wastes (COWs), e.g., organochlorine. However, the operational temperatures are usually high, and local structure and thermodynamic property of the molten salt remain largely unclear. In this study, novel molten NaOH-KOH is developed for organochlorine destruction, and its eutectic point can be lowered to 453 K with 1:1 mol ratio of NaOH to KOH. Further experiment shows that this molten NaOH-KOH is highly-efficient towards the destructions of both trichlorobenzene and dichlorophenol, acquiring the final dechlorination efficiencies as 88.2% and 94.1%, respectively. The organochlorine destruction and chloride salt enrichment are verified by fourier-transform infrared spectrometer. Molten NaOH-KOH not only eliminates the C-Cl and CC bonds, but also traps generated CO2, other acidic gases, and possibly particulate matters as a result of the high surface area and high viscosity. This makes it possibly advantageous over incineration for organic waste destruction for carbon neutrality. To sufficiently reveal the inherent mechanism for the temperature dependent performance, molecular dynamics simulation is further adopted. Results show that the radial distance between ions increases with temperature, causing larger molar volume and lower resistance to shear deformation. Moreover, thermal expansion coefficient, specific heat capacity, and ion self-diffusion coefficient of the molten NaOH-KOH are found to increase linearly with temperature. All these microscopic alterations contribute to the organochlorine destruction. This study benefits to develop highly-efficient molten system for COWs treatment via a low-carbon approach.

Phenol Liquefaction of Waste Sawdust Pretreated by Sodium Hydroxide: Optimization of Parameters Using Response Surface Methodology.

In this study, a two-step method was used to realize the liquefaction of waste sawdust under atmospheric pressure, and to achieve a high liquefaction rate. Specifically, waste sawdust was pretreated with NaOH, followed by liquefaction using phenol. The relative optimum condition for alkali-heat pretreatment was a 1:1 mass ratio of NaOH to sawdust at 140 °C. The reaction parameters including the mass ratio of phenol to pretreated sawdust, liquefaction temperature, and liquefaction time were optimized by response surface methodology. The optimal conditions for phenol liquefaction of pretreated sawdust were a 4.21 mass ratio of phenol to sawdust, a liquefaction temperature of 173.58 °C, and a liquefaction time of 2.24 h, resulting in corresponding liquefied residues of 6.35%. The liquefaction rate reached 93.65%. Finally, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) were used to analyze untreated waste sawdust, pretreated sawdust, liquefied residues, and liquefied liquid. SEM results showed that the alkali-heat pretreatment and liquefaction reactions destroyed the intact, dense, and homogeneous sample structures. FT-IR results showed that liquefied residues contain aromatic compounds with different substituents, including mainly lignin and its derivatives, while the liquefied liquid contains a large number of aromatic phenolic compounds. XRD showed that alkali-heat pretreatment and phenol liquefaction destroyed most of the crystalline regions, greatly reduced the crystallinity and changed the crystal type of cellulose in the sawdust.

Prediction of the Maximum Compressive Strength Geopolymers Using the Method of Weighted Chemical Compositions of Binders

Geopolymers are composite hard materials made by mixing solid binders such as fly ash and slag, and alkaline liquid activators such as NaOH and sodium silicate. Geopolymers have recently been developed to be used as a replacement for portland cement concrete. Industrial by-products, such as fly ash, steel making slags and garbage melting furnace slags, can be used to create geopolymers in a process that emits less carbon dioxide than does cement making. This reduction in CO2 emission is important because CO2 is one of the substances known to contribute to global warming. In the future, further uses of these fly ashes and slags must be explored. The development of high compressive strength geopolymers using fly ash and slags will strongly contribute to the fields of construction, geotechnical engineering, and architecture. The compressive strength of geopolymers, qu, is generally considered to be a function of the weight ratio of activator to binder, w, and the weight ratio of NaOH to sodium silicate, η. The maximum compressive strength, qumax, is determined as the maximum value among the peak values of qu, which were obtained for various values of w and η. The values of w and η that yield the maximum compressive strength, qumax, are defined as the optimum values wopt and ηopt, respectively. When designing geopolymers, it is essential to establish a method to predict qumax using the chemical compositions of the binders only. This research first determines the chemical and physical properties of geopolymer materials by using scanning electron microscopy (SEM) and X-ray diffraction (XRD) observations, and then determines the mechanical properties of qumax, and finally devises a method to predict qumax by combining SiO2, Al2O3, and CaO in binders.

Fabrication of multifunctional carbon/clay nanocomposites by recycling oil shale semi-coke waste for coloring and enhancing mechanical and aging-resistant properties of acrylonitrile–butadiene–styrene

With the increasingly demanding of environmental regulations, the disposal and sustainable resource utilization of industrial solid waste have attracted much attention. The carbon/clay nanocomposites were successfully fabricated derived from oil shale semi-coke waste via NaOH-assisted hydrothermal technology for coloring and reinforcing of acrylonitrile–butadiene–styrene in this study. The obtained nanocomposites were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and energy dispersive spectroscopy. With the increase in the mass ratio of NaOH to oil shale semi-coke, kaolinite, quartz, and other minerals in oil shale semi-coke gradually changed to analcine-C to faujasite-Na to sodalite, while the morphologies of carbon/clay nanocomposites transformed from nanosheets to nanosheets/nanorods to nanorods. Different morphologies had different effect on the mechanical properties of ABS, and the mixed-dimensional morphologies of the nanocomposites obviously improve the mechanical performances due to their synergistic effect compared with sheet-like and rod-like carbon/clay nanocomposites, respectively. Furthermore, the incorporation of carbon/clay nanocomposites into acrylonitrile–butadiene–styrene also enhanced its aging-resistant properties compared with the pure acrylonitrile–butadiene–styrene. Therefore, this study provides a feasible approach to realize the resource and sustainable utilization of oil shale semi-coke solid waste as functional filler for polymers.

Thermodynamic analysis of caustic–roasting of electric arc furnace dust

Electric Arc Furnace Dust (EAFD) is a byproduct of the steelmaking industry, which is one of the most significant and rapidly generated hazardous waste. This material includes recyclable elements such as zinc (Zn) and iron (Fe), exclusively in the form of zinc-ferrite (ZnFe2O4), zincite (ZnO), magnetite (Fe3O4) with some other minor compounds of Si, Mn, Mg, and Pb. A combination of pyro and hydrometallurgical route, also known as hybrid process, has acquired considerable attention to extract Fe and Zn from electric arc furnace dust (EAFD). In the current study, systematic thermodynamic assessments using thermochemical–software FactSage and targeted experimental investigations were carried out to assess the suitability of the caustic-roasting step of this important hybrid process. Thermodynamic calculation of the effect of different parameters on the conversion of EAFD to a suitable feedstock for the next separation stages showed that the major zinc-ferrite (ZnFe2O4) phase of EAFD can be potentially converted to ZnO and sodium-ferrite (NaFeO2) intermediate phase while reacting with NaOH (>2 mol) at temperatures equal or higher than 100 °C. The suitable condition was assessed to an EAFD to NaOH ratio of 1:3 M fraction and a temperature, T > 318 °C at the normal atmospheric condition. Moreover, the selected experimental investigation was also showing a good agreement with the current thermodynamic assessment.

Response Surface Analysis (RSA) optimization of temperature-resistant gel foam fabrication and performance evaluation

For applications in high temperature environments, a high temperature resistant gel foam formulation with a novel semi-interpenetrating network structure was created. It was specifically determined experimentally what affects component concentration and temperature had on gelation time, gelation strength, and foam qualities by the use of a single-factor screening research and response surface analysis (RSA). The findings revealed that the foam volume grew from 370 ml to 390 ml before and after aging at 100 °C, the precipitation half-life was increased from 25 min to 50.4 min. The foam stabilization period was doubled by the optimized temperature-resistant gel foam, which also greatly improved temperature resistance. The gel foam performed best when the coordination ratios of NaOH, AA, AMPS, MBA, APS, sodium streptavidin sulfonate (AOS), alkyl glycoside (APG0810), alkyl amide betaine (FM-20AB), and silicone resin polyether emulsion (MPS) were 1.4 %, 5 %, 2.4 %, 0.7 %, 0.1 %, 1.6 %, and 0.2 %, respectively. The SEM examination and thermal weight loss investigation showed that the enhanced gel foam generated an enhanced mechanism with greater temperature resistance and stability and considerable potential application areas.

The Effect of Mixture Proportion on the Performance of Alkali-Activated Slag Concrete Subjected to Sulfuric Acid Attack.

Long-term deterioration and durability concerns in harsh environments with acidic attacks are considered as the weaknesses of ordinary Portland cement (OPC) concrete. Although the performance of alkali-activated slag concrete (AASC) has been reported to be superior in acidic environments, there is a poor understanding regarding the impacts of diverse mix design parameters on AASC durability in an acidic environment. This research aims to understand the impact of mix design parameters on the durability of AASC in the sulfuric acid (H2SO4) environment with pH = 3. The type of alkaline solution, the molarity of alkaline solutions, the weight ratio of alkaline solutions to slag, and the weight ratio of NaOH to Na2SiO3 are mix design parameters investigated in this study. The compressive strength reduction and weight loss were monitored from early ages up to 180 days. Moreover, an OPC concrete sample was produced as a reference.

Removal of Polytungstate from Mine Wastewater Using a Flat Renewal Membrane Reactor with N1633 as a Carrier.

A novel flat renewal membrane reactor (FRMR) with mixed amine extractant N1633 dissolved in kerosene and NaOH solvent was studied for the removal of polytungstate [expressed as W7O246− or W (VI)] from simulated mine wastewater. FRMR contains three parts: the feeding cell, reacting cell and renewal cell. A flat membrane of polyacrylonitrile (PAN) was used in the reacting cell, which used mixed solutions of kerosene and NaOH. The amine extractant (N1633) was used as the carrier, and simulated mine wastewater containing polytungstate was used as the feeding solution. The influencing factors of the pH and the other ion strengths in the feeding solutions, the volume ratio of kerosene to NaOH solution, and the N1633 concentration in the renewal solutions were investigated in order to obtain the optimum technique parameters. It was found that the removal percentage of polytungstate could reach 92.5% in 205 min, when the concentration of the carrier (N1633) was 0.18 mol/L, the volume ratio of kerosene and NaOH in the renewal cell was 3:2, the pH in the feeding cell was 4.00, and the initial concentration of polytungstate was 3.50 × 10−4 mol/L. The stability and feasibility of FRMR were tested by the investigation of polytungstate retention and the reuse of the membrane.

Studies on the microstructure and durability characteristics of ambient cured FA-GGBS based geopolymer mortar

The present study involves evolving a mix proportion for geopolymer mortar cured at ambient temperature, utilizing the by-products of industries like fly ash (FA) and ground granulated blast-furnace slag (GGBS) as the binder. The parameters such as proportions of FA and GGBS, molarity of NaOH solution, Na2SiO3 /NaOH ratio, and alkaline liquid/binder ratio were considered. The consistency, setting time, and compressive strength for different percentages of FA replacement with GGBS were studied. It was observed that the addition of GGBS at 10–30 % is suitable for achieving the compressive strength at ambient temperature curing. Hence to assess the practical application of geopolymer mortar, microstructure studies at curing age of 90 days and durability tests over an exposure period of 180 days were conducted on F70:G30, F80:G20, F90:G10 mortar specimens and compared with ordinary Portland cement (OPC) control mixes. SEM, XRD, and FTIR results revealed the polymerization process in the geopolymer and hydration in OPC. Compared to F80:G20 and F90:G10 specimens, the microstructure of F70:G30 specimens containing a more significant proportion of GGBS showed a denser microstructure due to the increased C-A-S-H gel formation. TGA was used to determine the percentage of weight loss with the increase in temperature at curing age of 90 days. It was found that the extent of decomposition of compounds at high temperatures is lower in geopolymer mortar (F70:G30) than in OPC mortar. In addition, it was found that geopolymer mortar (F70:G30) has better resistance to water absorption, sorptivity, acid attack, sulfate attack, marine water attack, and chloride ion penetration and have equivalent mechanical qualities to the OPC control mix.

Effect of the Mortar Volume Ratio on the Mechanical Behavior of Class CI Fly Ash-Based Geopolymer Concrete

This research described the effect of the mortar volume ratio on the mechanical behavior of Class CI fly ash-based geopolymer concrete. The absolute volume ratio parameters were designed to determine the effects on the mechanical properties of the geopolymer concrete. The volume ratio of the mortar to coarse aggregate voids (Rc) was increased by 0.25 increments, from 1 to 1.75, using constant parameters of 10 M NaOH at a ratio of Na2SiO3to NaOH (R). Furthermore, the alkaline to fly ash ratio (A) of 0.35 and the volume ratio of paste to fine aggregate voids (Rm) of 1.5 were based on geopolymer paste and mortar investigations previously published. The test results showed that 1) the Rc ratio influences the workability and compressive strength of geopolymer concrete; 2) the increase in the Rc ratio by 1.75 is not linear with the rise in compressive strength but produces better mechanical properties; 3) it does not affect the tensile strength of both geopolymer and OPC concretes; 4) the lower the Rc ratio, the higher the flexural strength; 5) the Rc ratio does not affect the OPC concrete and GC tensile strength; 6) the bond stress in geopolymer concrete with an Rc ratio of 1.75 is higher than in OPC concrete; and 7) Rc ratio does not affect the early strength of geopolymer concrete. The geopolymer concrete experienced an increase in compressive strength after 28 days, while the OPC concrete remained flat. The results will help develop an optimal mix design of Class CI fly ash with moderate calcium oxide in the production of geopolymer concrete. This will improve the future applications of using this process in new binding materials. Doi: 10.28991/CEJ-2022-08-09-012 Full Text: PDF

The designing of degradable unsaturated polyester based on selective cleavage activated hydrolysis and its application in recyclable carbon fiber composites

In recent years, the extensive application of unsaturated polyester resins (UPRs) and their composites has resulted in an increasing environmental problem and it is necessary to find a simple and efficient recycling method especially for the high-value reinforced fibers. Here a self-polymerizable dimethacrylate monomer containing a cleavable unit, β-carbonyl hindered urethano, was designed for a degradable UPR which has a good flexible strength of 79 MPa and Tg of 119.7 °C. Moreover, through the hydrolysis of ester that was previously activated by selective cleavage of hindered C–O bond in urethano, the resin could be directly degraded in an aqueous solution (4/1 M ratio of hydrazine and NaOH and 0.04 mol/mL of total concentration) at 80 °C in 4 h, and the degraded products could be simply separated by solubility. Furthermore, its carbon fiber composite was degraded in only 2.5 h and the recycled carbon fiber fabrics well maintained their original woven structure, surface chemical composition, graphitized structure and mechanical strength. This work provides a new method for efficient degradation and recycling of fiber reinforced thermosetting resin composites.

Flexural Performance and Microstructural Studies of Trough-Shaped Geopolymer Ferrocement Panels.

Geopolymer mortar is the best solution as an alternative to cement mortar in civil engineering. This paper deals with the effect of geopolymer mortar on the strength and microstructural properties under ambient curing conditions. In this research, geopolymer mortars were prepared with fly ash and steel slag (in the ratio 1:2.0, 1:2.5 and 1:3.0) as precursors with NaOH and Na2SiO3 as activator solution solutions (in the ratios of 0.5, 0.75 and 1.0) with concentrations of NaOH as 8 M, 10 M, 12 M and 14 M to study the compressive strength behaviour. From the experimental results, it was observed that the geopolymer mortar mix with the ratio of fly ash and steel slag 1:2.5, 12 M NaOH solution and the ratio of NaOH and Na2SiO3 0.5 exhibits the maximum compressive strength results in the range of 55 MPa to 60 MPa. From the optimized results, ferrocement panels of size 1000 mm × 1000 mm × 50 mm were developed to study the flexural behaviour. The experimental results of the flexural strength were compared with the analytical results developed through ABAQUS software. It was observed that the Trough-shaped geopolymer ferrocement panel exhibits 56% higher value in its ultimate strength than the analytical work. In addition to the strength properties, microstructural analysis was carried out in the form of SEM, EDAX and XRD from the tested samples.

Phase diagram for hydrothermal alkali activation of kaolin and quartz: Optimal digestion for the synthesis of zeolites

Low-temperature activation of quartz and kaolin, two of the most abundant and affordable raw materials as the sources of alumina and silica for the production of zeolites, is highly desirable but is hampered by several challenges such as incomplete activation and the formation of acid-resistant aluminosilicates. In this paper, the hydrothermal alkali activation processes of kaolin and quartz with different Si/Al ratios have been studied in detail, aiming to establish a phase diagram for the optimal digestion of silica and alumina. The effects of the Si/Al ratio, reaction time, reaction temperature, alkali concentration, and doses of hydrothermal alkali activation have been thoroughly investigated and optimized. Sodalite, hydroxycancrinite and analcime are found to be the dominant aluminosilicates as activation products. This is the first demonstration that the molar ratio of NaOH/(Si + Al) is the key factor in controlling the formation of aluminosilicates. The establishment of this phase diagram allows us to avoid the formation of troublesome analcime, and it can be used for effectively converting most natural aluminosilicate materials into sol-gel as platform chemicals for the synthesis of zeolites and other aluminosilicate derivatives.

Variasi Molaritas Naoh Dan Alkali Aktivator Beton Geopolimer

Cement as a building material for concrete produces CO2 which can damage the earth's atmosphere. Therefore, environmentally friendly geopolymer concrete is the choice. The main ingredients for making this concrete are pozzolanic materials which are rich in Silica (SiO3) and Alumina (Al2O3) as a substitute for cement and alkali activator in the form of Sodium Hydroxide (NaOH) and (Na2SiO3) as binders.This study aims to determine the variation of the mixture for the highest compressive strength. The ratio of fly ash type F and alkali activator is 74%:26%. The molarity of NaOH used was 10M, 12M, 14M, the ratio of Na2SiO3 and NaOH was 2.5:1; 3.0:1; 3.5:1. The test object is cylindrical size 15cm x 30cm and the compressive strength test is 28 days old.The test results with the ratio of NaOH and Na2SiO3 2.5:1 at 10M, 12M, 14M NaOH are 25.81 Mpa, 27.00 MPa, 28.98 MPa. While the compressive characteristics are 24.32 Mpa, 24.67 Mpa, 26.58 Mpa. The test results show that the ratio of molarity and alkali activator greatly affects the compressive strength and workability of geopolymer concrete. High molarity will produce high compressive strength. Meanwhile, the higher the alkali activator ratio, the lower the compressive strength produced.Â

Copper and zinc extraction from underspoil waters using sulfur solution in sodium hydroxide

During the passage of atmospheric precipitates through the porous dump body, the products of oxidation of sulfide minerals are dissolved. As a result, underspoil waters with low pH values and a significant amount of dissolved metals are formed. For the most part, all types of the sewage produced by mining and processing enterprises (underspoil, colliery, pit, drainage) are combined before treatment, which leads to the formation of a common water yield with complex chemical composition. According to the existing practice, the combined flow is neutralized with lime milk, which leads to irretrievable losses of non-ferrous metals with mud after neutralization. The use of the sulfiding method as part of the tactics of locally autonomous processing makes it possible to obtain the copper and zinc commercial products suitable for further metallurgical processing. Previously, sulphides of biogenic or chemical nature, as well as hydrogen sulphide, have been used in extraction of metals in the form of sulphides. In this study, we have used sulfur solution in sodium hydroxide with a mass ratio of NaOH:S = 1:1 as an alternative to the old reagents. During the study, the sulfur consumption for copper and zinc extraction were determined. The impact of water pH on zinc extraction is shown. The pilot-scale tests have confirmed the results of laboratory studies. Proposed is a flow chart with the following main operations: copper extraction, zinc extraction and the zinc product conditioning. Copper concentrate with a copper content of 32.9% and zinc concentrate with a zinc content of 48% were obtained. In the resulting deposits, copper is in the form of covellite (CuS), and zinc is in the form of sphalerite (ZnS). Through metal extraction was 99.9% for copper and 99.5% for zinc.

SPENT EDIBLE OIL SOAP ANALYSIS ON CHEMICAL PRACTICUM ACTIVITIES IN SMA HARAPAN III DELI SERDANG

Spent edible oil is the result of repeated frying that is mostly done in the fast food industry or in household activities and generally this used cooking oil is disposed of as waste that pollutes the waters in the environment. Spent edible oil is a good ingredient for soap making because its raw material is relatively cheaper than most oils. In a simple laboratory study conducted by students of SMA Harapan III Deli Serdang, soap was made from used cooking oil using alkaline NaOH. The saponification process was carried out using used edible oil soap 0.3 parts by mass ratio of NaOH at a concentration of 30% and 1 part of used edible oil bleached with activated charcoal. The analysis of edible oil soap that has been made by determinate the value of free alkali with acid-base titration method and foam stability test. The results obtained from the determination of the foam test provide foam stability of 83.3% and free alkali content of 0.211%. This soap provides a fairly stable foam stability, but it still feels hot in the hands due to the alkaline NaOH that is used not completely soaped in the washing process. The use of edible oil into soap by students can increase knowledge and can be applied to overcome environmental pollution due to the disposal of edible oil into the environment.

A Scientometric Review of Na2SiO3/NaOH Versus SiO2/Na2O is above 2.85:1 Alkaline solution Activated Geopolymer Concrete

The term geopolymer is a sustainable binder refers to the study of waste mate- rials containing silicon (Si) and aluminum (Al), which create an alternative binder formed by a complex repeated chain by geopolymerization process. Hellacious materials alternation is mandatory to see the construction as a beautiful infrastructure as there are limited natural resources to produce qual- ity concrete. Alternative binder and aggregates created by using industrial waste should be used to reduce the disadvantages of conventional concrete. The Na2SiO3 / NaOH ratio activated geopolymer concrete has been well doc- umented by researchers. The ratio of these solutions to the field geopolymer concrete production is not suitable for structural geopolymer concrete because it is not possible to provide a temperature greater than 60 degree centrigrade in the field. The Na2SiO3 / NaOH ratio should be mixed 24 hours before airing the samples. Researchers have used a single alkaline solution simply instead of water when mixing concrete. In this review paper clearly compared and ana- lyzed difference between the Na2SiO3/NaOH activated geopolymer concrete versus neutral grade sodium silicate (NGSS) laboratory-based field construc- tion geopolymer concrete. NGSS is a neutral grade of SiO2: Na2O. This solu- tion is the only single neutral grade solution with 2.92 silica modulus, produced directly by the company to create the geopolymer.

Morphological guided sphere to dendrite BiVO4 for highly efficient organic pollutant removal and photoelectrochemical performance under solar light

Monoclinic BiVO4 (m-BiVO4) has been reported as promising phase for solar light driven photocatalysis. However, in the case of morphology guided BiVO4 with different synthetic conditions maintaining the m-BiVO4 phase remains a substantial challenge for achieving an efficient photocatalyst driven by solar light. Herein, a simple hydrothermal approach was used to produce well-defined template free m-BiVO4 dendrites with distinct branches for photo catalytically removal of organic pollutant and photocurrent generation. The development of monoclinic dendrite BiVO4 was confirmed after comprehensive structural, morphological, and optical examinations. FE-SEM images of m-BiVO4 revealed transformation of spherical to dendritic morphology with distinct branches by simply changing the HNO3 to NaOH ratios from 2:1 to 2:2, which are named as BVO 2-1 and BVO 2-2, respectively. The BVO 2-2 dendrites exhibited improved activity of 98% towards methylene blue (MB) photodegradation upon simulated solar light irradiation. The BVO 2-2 dendrites photoelectrode showed an outstanding photocurrent density of 1.4245 mAcm−2 than that of the BVO 2-1 spherical photoelectrode (0.7367 mAcm−2). Enhanced photocatalytic and photoelectrochemical action, could be ascribed to the unique morphological changes provides photoactive sites, harvest more light utilization together with higher separation of e−/h+ pairs. Furthermore, photocatalytic mechanism is investigated based on scavenger trapping agent, valence band XPS, UV Visible DRS and PL study. Our findings could pave the way for the development of dendritic nanostructure photocatalysts with improved photocatalytic activity.