Area Size Research Articles

A newly NH2-UiO-66 composite functionalized by molecularly imprinted polymer for selective and rapid removal of sulfamethoxazole

Metal–organic frameworks (MOFs) are used as novel adsorption materials owing to their large surface area and tunable pore size. However, the lack of selectivity considerably limits their application. Consequently, designing functionalized MOFs with specific recognition abilities is essential for enhancing their adsorption performance. Herein, we synthesized a functionalized NH2-UiO-66 composite modified by molecularly imprinted polymers (MIP@NH2-UiO-66) via a one-step polymerization process in which NH2-UiO-66 and MIP were formed simultaneously. Results demonstrate that MIP@NH2-UiO-66 effectively recognized sulfamethoxazole (SMX) in complex matrices. The adsorption equilibrium was reached in only 30 min, and this fast SMX adsorption on MIP@NH2-UiO-66 was described by the Avrami kinetic model, which indicates a spontaneous and exothermic adsorption process. Within the pH range of 3.0–10.0, MIP@NH2-UiO-66 exhibited an optimal binding capacity for SMX, and the maximum adsorption of SMX was 68.36 mg g−1 at 25°C, which exceeded those of existing adsorption materials (< 60.10 mg g−1). Additionally, MIP@NH2-UiO-66 was regenerated for ∼17 cycles compared to less than eight cycles for the other adsorbents. MIP@NH2-UiO-66 effectively removed 90.58%–99.60% of SMX from river water, rainwater, soil, sediment, chicken, pork, and milk samples, with a relative standard deviation of less than 4.43%. The superior adsorption of SMX on MIP@NH2-UiO-66 was primarily driven by the synergistic effects of the imprinting sites, hydrogen bonding, and electrostatic forces. The one-step polymerization method substantially simplified the synthesis process and reduced the costs, which are promising factors for the synthesis of MOFs with high selectivity.

Study on Spatial Scale Selection Problem: Taking Port Spatial Expression as Example

Spatial scale is a key factor, which affects the accuracy of spatial expression and further influences the spatial planning of a research area. In order to help improve the efficiency and accuracy of optimal scale selection for all sizes of research areas, a universal two-layer theoretical framework for optimal scale selection was proposed in this paper. Port area was taken as an example to systematically clarify the application of the proposed framework, and the scale selection model for port spatial expression was established. Least-squares-based mean change point analysis was introduced into the model, and the concept of a comprehensive change point was proposed to form the criterion for optimal port scale selection. First, an appropriate scale domain was preliminarily determined by the upper scale selection model. Then, the lower scale selection model determined the final appropriate scale domain and took the corresponding scale of a minimum comprehensive change point as the final optimal scale for port spatial expression. Finally, a port area in Qingdao in eastern China was taken to verify the feasibility of the proposed model, and the optimal scale was suggested to be 14 m. The proposed framework in this paper helps ensure the accuracy of spatial expression and reduce spatial data redundancy, and it can provide the methodological references for planners to better spatialize a research area, which will guarantee the subsequent spatial planning work.

SAL Method Applied in Grid Forecasting Product Verification with Three-Source Fusion Product

Quantitative precipitation forecast (QPF) verification stands out as one of the most formidable endeavors in the realm of forecast verification. Traditional verification methods are not suitable for high-resolution forecasting products in some cases. Therefore, the SAL (structure, amplitude and location) method was proposed as a method of object-based spatial verification that studies precipitation verification in a certain range, which is combined with factors including structure, amplitude and location of the targets. However, the setting of the precipitation threshold would affect the result of the verification. This paper presented an improved method for determining the precipitation threshold using the QPF from ECMWF, which is an ensemble forecast model and three-source fusion product that was used in China from 1 July to 31 August 2020, and then the results obtained with this method were compared with the other two traditional methods. Furthermore, the SAL and the traditional verification methods were carried out for geometric, simulated and real cases, respectively. The results showed the following: (1) The proposed method in this paper for determining the threshold was more accurate at identifying the precipitation objects. (2) The verification area size was critical for SAL calculation. If the area selected was too large, the calculated SAL value had little significance. (3) ME (Mean Error) could not identify the displacement between prediction and observation, while HSS (Heidke Skill Score) was sensitive to the displacement of the prediction field. (4) Compared with the traditional verification methods, the SAL method was more straight forward and simple, and it could give a better representation of prediction ability. Therefore, forecasters can better understand the model prediction effect and what needs to be improved.

Abstract 4140136: Aortic Valve Calcification Density Performs Better Compared to Absolute Aortic Valve Calcification in Aortic Stenosis Risk Stratification

Aortic valve calcification (AVC) scores can be used to stratify aortic stenosis (AS) severity. Current practice guidelines recommend use of absolute AVC scores without considering body surface area or aortic annulus size. We investigated whether size variation in aortic annular area should be considered in identifying optimal AVC cutoffs for patients with severe AS. This was a retrospective analysis of AS patients that underwent AVC assessment during 2018-2023. Outcomes were composite of valve intervention or all-cause mortality. AVC density was defined by dividing AVC by echo-derived left ventricular tract area. Receiver operator curve analysis determined optimal AVC density scores. Absolute AVC cutoffs of &gt;1200AU for females and &gt;2000AU for males were used to identify severe AS. The study included 749 patients (mean age 78 years, 46% female). Median CT-annulus area was larger for males compared with females (532mm 2 [Q1, Q3: 479, 582] vs. 413mm 2 [370, 458], p&lt;0.001). There was a strong association of absolute AVC with CT-annulus area for both males and females (Spearman coefficient: 0.87 and 0.83, p&lt;0.01 each) respectively (Figure 1). The optimal AVC density cutoffs for males and females were 427 and 326, respectively (accuracy 76%, sensitivity 83%, specificity 51%). Composite outcomes were better differentiated with AVC density (males: HR 2.48, 95% CI: 1.82-3.37, p&lt;0.001; females: HR 2.37 (1.71-3.28), p&lt;0.001) compared with absolute AVC scores (males: HR 1.81 (1.43-2.30), p&lt;0.001; females: HR 2.11 (1.62-2.74), p&lt;0.001) (Figure 2). AVC is strongly associated with CT-annulus area and risk stratification is improved with the use of AVC density compared with absolute AVC. This may be especially helpful in patients with extremes of annulus area sizes.

KOH Activation Mechanism in the Preparation of Brewer’s Spent Grain-Based Activated Carbons

Understanding the mechanism of KOH activation in the preparation of activated carbon (AC) enables more efficient utilization of biomass. In this study, brewer’s spent grains (BSGs) were carbonized at 500 °C to produce biochar (BC), followed by KOH activation under different activation conditions. The gas and solid products generated during the activation process were analyzed by gas chromatography (GC), X-ray diffraction (XRD), Raman analysis, a surface area and pore size analyzer, and X-ray photoelectron spectroscopy (XPS). The results show that increasing the KOH/BC ratio or the activation temperature could both promote gas production. XPS results indicated that the activator reacted first with -COOH and then with -OH of ACs, with AC5-700 having the highest C-OH content (50.04%). As the KOH/BC ratio increased, more aromatic structures were destroyed, and the porosity of ACs was significantly enhanced, with AC7-700 having the highest Brunauer–Emmett–Teller (BET) specific surface area (SBET) (2997.69 m2/g). At low temperatures, KOH reacted with the active groups of BC and carbon at the edge of the aromatic structure. At high temperatures, the activator (KOH, K2O, and K2CO3) reacted with carbon in the aromatic structure to generate a large number of pores on ACs and expand them. ACs exhibited more pores with higher KOH addition, and a higher activation temperature did not generate more new pores, but expanded the pores more significantly than high KOH addition.

Synthesis and Evaluation of the Extraction Efficiency of Pristine Zeolite Na-A to Remove ReO4- Ions (Surrogate of 99TcO4-) from a Simulated Low-Level Waste Solution.

Zeolite Na-A was synthesized through hydrothermal, alkali-fusion, and sonochemical methods, using kaolin as an economically viable precursor. The synthesized zeolite Na-A samples were characterized using XRD, FT-IR, SEM, and Raman spectroscopy. Specific surface area and pore size distribution analyses (by BJH and DFT models) were conducted using a BET surface area analyzer. Additionally, thermal degradation studies were performed by TG-DTA to check the thermal stability of zeolite Na-A at high temperatures. Furthermore, kaolin-derived zeolite Na-A was employed for the extraction of perrhenate ions (ReO4-), which are a nonradioactive surrogate for pertechnetate ions (99TcO4-) without any postsynthetic modifications (using toxic surfactants, etc.) utilizing in situ modification of the solution medium for the first time. The sonochemically synthesized zeolite Na-A demonstrated superior sorption performance for the solid-phase extraction of ReO4- ions from the simulated low-level waste solution. The adsorption process was found to follow pseudo-second-order kinetics. The Langmuir isotherm model fit perfectly with the experimental data (R2 = 0.997) and exhibited a maximum sorption capacity of 926.8 mg/g at pH ∼11, showing superior sorption capacities compared to those of the numerous materials reported earlier. XPS confirmed the speciation of extracted rhenium as NH4Re(VII)O4, providing critical insights into the adsorption mechanisms and validating the suitability of the sonochemically synthesized zeolites toward ReO4- sorption. Furthermore, Raman studies of ReO4- adsorbed zeolite Na-A reflect the absence of characteristic breathing bands, indicating the closure of the pore openings due to the occupancy of adsorbate moieties within the pores. This study not only highlights the utilization of sonochemically synthesized zeolite Na-A as an efficient, benign, and cost-effective adsorbent for 99TcO4- removal from nuclear waste but also emphasizes its potential sustainable applications in various other industrial processes such as wastewater treatment, catalysis, gas separation, pollution control, and resource recovery from industrial effluents and in the pharmaceutical industry for selective ion removal.

Statistical Analysis of Atmospheric Delay Gradient and Rainfall Prediction in a Tropical Region

In recent years, precipitable water vapor has emerged as a key atmospheric parameter in weather prediction research. However, relying on only one parameter does not always accurately predict rainfall, as other atmospheric parameters also contribute to initiating rain events. In our previous study, we explored a methodology for rainfall forecasting based on the atmospheric delay gradient at an individual station in the tropical region. Commonly referred to as the atmospheric gradient, it accounts for the delay in GNSS signals due to changes in horizontal refractivity while propagating through the troposphere to the ground station. This paper discusses the spatial and temporal correlation of the gradient with precipitation occurring over a region. We have investigated different features, such as gradient magnitude, gradient convergence, and the flux of the atmospheric gradient, to propose potential nowcasting criteria for precipitation in the tropical climatic zone. The atmospheric gradient in the surrounding region orients toward the area of precipitation as the rain event approaches. This gradient gradually alters its orientation and converges toward the region of rainfall at the time of precipitation, introducing the concept of gradient convergence. This phenomenon results in an inward gradient flux at the time of the downpour, which presents a potential parameter for rainfall prediction over an area. We also proposed investigating area sizes of 4° × 4° or 8° × 8°, depending on the gradient feature, to establish a forecasting methodology for rainfall. The weather front in the tropical region begins to initiate 12 h before the actual time of occurrence and advances toward the area where it will have an impact from a more distant location. This article presents a detailed investigation of various features of the atmospheric gradient and its potential to nowcast rainfall for a region, as well as proposes the lead time for long-term weather predictions. Furthermore, a deep neural network has been employed to predict rainfall events for the next 6 h over an area in the tropical region.

Improved infiltration rate determination method for interlocking-block permeable pavements using standard ASTM test apparatus

ABSTRACT Current standard methods of measuring permeability of interlocking-block permeable pavements (IBPPs) do not correctly measure the actual infiltration rates of IBPPs. The test results vary with test area size and location. In this study, employing the standard ASTM-1781 test apparatus, an improved procedure that adopts an experiment-based numerical approach is developed to overcome the problem. It involves the following steps: (i) Perform falling-head infiltration tests using ASTM-1781 apparatus to obtain infiltration flow data; (ii) Develop computational fluid dynamic (CFD) finite-volume models for different infiltration test conditions; and (iii) Apply appropriate finite-volume model to calculate the effective IBPP infiltration rate under any given surface water depth on the IBPP. Experimental tests were conducted to validate the proposed method.

2D Nitrogen-Doped Graphene Materials for Noble Gas Separation.

Noble gases, notably xenon, play a pivotal role in diverse high-tech applications. However, manufacturing xenon is an inherently challenging task, due to its unique properties and trace abundance in the Earth's atmosphere. Consequently, there is a pressing need for the development of efficient methods for the separation of noble gases. Using mild fluorographene chemistry, nitrogen-doped graphene (GNs) materials are synthesized with abundant aromatic regions and extensive nitrogen doping within the vacancies and holes of the aromatic lattice. Due to the organized interlayer "nanochannels", nitrogen functional groups, and defects within the two-dimensional (2D)structures, GNs exhibits effective selectivity for Xe over Kr at low pressure. This enhanced selectivity is attributed to the stronger binding affinity of Xe to GN compared to Kr. The adsorption is governed by London dispersion forces, as revealed by theoretical calculations using symmetry-adapted perturbation theory (SAPT). Investigation of other GNs differing in nitrogen content, surface area, and pore sizes underscores the significance of nitrogen functional groups, defects, and interlayer nanochannels over thesurface area in achieving superior selectivity. This work offers a new perspective on the design and fabrication of functionalized graphene derivatives, exhibiting superior noble gas storage and separation activity exploitable in gas production technologies.

Identification of Agricultural Socioeconomic Factor and Its Relationship with Exports of Palm and Palm Kernel Oils in Indonesia

The research aim was to study the influence of area size consisting of Government Estate (Government Estate), Private Estate (PBS), Smallholder (PR), price and exchange rate on production, and the influence of production, price and Exchange rate on palm oil exports which consists of Crude Palm Oil (CPO) and Palm Kernel Oil (PKO) using panel data for 2000-2022. Whether viewed from CPO or PKO, the results of the analysis show that the Government State has a real negative influence on production where the elasticity of the Government Estate for CPO towards production is lower than for PKO. The increase in production was significantly caused by the increase in PR for both CPO and PKO, where the elasticity of the increase in PR for CPO was higher than the increase in PKO. PBS provides a positive influence on production which is significant for PKO but not significant for CPO, while prices and exchange rates do not have an influence on CPO production, nor on PKO production. CPO and PKO exports are significantly influenced by prices, where CPO's price elasticity is higher than that of PKO. Furthermore, production and exchange rates have no influence on exports of either CPO or PKO, while the increase in CPO exports is determined significantly by PR, where the elasticity of CPO is higher than PKO.

Developing a Model to Study Walking and Public Transport to Attractive Green Spaces for Equitable Access to Health and Socializing Opportunities as a Response to Climate Change: Testing the Model in Pu’er City, China

Green space is not always equitably located in cities, and the attractiveness of green space varies, leaving some residents with easy access to high-quality parks and others with little or no access or access to under-maintained parks. To remedy these inequities, this study identified attractive and well-utilized recreational green spaces and developed a model to measure the likelihood of using these recreational green spaces (PSG). The goal was to reduce the travel time and cost of walking or using public transportation to get to green spaces and to design all green spaces to be attractive. The data come from the perspective of the city’s public transportation system and residents’ personal choices. First, the attractiveness of recreational green spaces was calculated from big data on the geolocation of cell phones, measuring the level of provision of recreational green spaces and the trip rates of urban residents. After that, the travel cost to reach recreational green space in residential areas was calculated according to residents’ travel habits. Finally, the probability of all recreational green spaces in the city being used was calculated by combining the population size of residential areas. Taking Pu’er City in China as an example, the attractiveness and utilization rates of recreational green spaces were calculated by PSG, and the results of the study showed that the probability of residents choosing to use the recreational green spaces that are closer to the residential area, with a larger population capacity, and with a higher attractiveness is the highest. The results of the study help promote equitable access to health and socialization opportunities for individuals and communities, thereby promoting environmental justice to help mitigate and respond to climate change.

Extraction of methamphetamine and pseudoephedrine by modified graphene oxide solid phase extraction method coupled to HPLC-UV in urine sample.

Methamphetamine, pseudoephedrine, and related drugs are among the first drugs used for the stimulation of the central nervous system. In this study, two adsorbents based on graphene oxide (GO) were synthesized and used for the analysis of methamphetamine and pseudoephedrine. The prepared nano-adsorbents based on GO in this study were coated by polyaniline (PANI) and Fe3O4/C-nanodot/GO (magnetic adsorbent). The average size of nanoparticles (GO/PANI) was 18.43nm. The specific surface area and pore size diameter of Fe3O4/C-nanodot/GO were 22.71 m2 g- 1 and 15.23nm, respectively. Experimental variables affecting the extraction efficiency of the analytes such as pH of the sample solution, amount of adsorbent, extraction time, and type of eluents were investigated and optimized by response surface methodology. Under optimum conditions, GO/PANI and Fe3O4/C-nanodot/GO were considered appropriate solid phase extraction adsorbents for HPLC-based analyses of the studied drugs in human urine samples. However, GO/Fe3O4 nano adsorbent (Fe3O4/C-nanodot/GO) showed superior working condition than GO/PANI. The validated proposed analytical methods can be used for the quantitative determination of methamphetamine and pseudoephedrine in actual samples.

Accumulation of Spherical Microplastics in Earthworms Tissues-Mapping Using Raman Microscopy

The presence of microplastics in the environment is now becoming a challenge for many scientific disciplines. Molecular diversity and spatial migration make it difficult to find plastic-free areas. Their negative, often toxic, effects affect plants and animals to varying degrees, causing many biochemical disorders, species degradation, and population changes. This study aimed to determine the possibility of accumulation of spherical low-density polyethylene particles of 38–63 µm (38–45 µm 1.00 g/cm3, and 53–63 µm 1.00 g/cm3) with fluorescent properties in muscle tissues of the cosmopolitan earthworm species Lumbricus terrestris, exposed to plastic contained in the soil at a concentration of 0.1% dry weight for 3 months. Analysis of the tissues by Raman microscopy included the estimation of mapping area size, sampling density, accumulation time, spectra, laser line, and laser power to detect plastic in the samples effectively. Our results demonstrate the ability of low-density polyethylene microparticles to accumulate in earthworm tissues and are presented graphically for the mapping area and images with plastic detection sites marked. In addition, this article highlights the potential of using Raman microscopy for research in the field of tissue analysis.

A 3D modelling approach to measuring structural characteristics of bird nest interiors

Abstract Nests are considered extended phenotypes of animals with potentially serious fitness consequences for the survival of offspring. Therefore, nest characteristics may contain valuable information about the underlying ecological and evolutionary mechanisms shaping animal reproduction. However, we currently lack efficient tools to archive nests and measure their characteristics, particularly concerning enclosed nests. Here we developed a step‐by‐step protocol of a 3D modelling approach to measure structural characteristics of nest interiors using the enclosed, dome‐shaped nests of Asian house martins as a test system. We first created the replicas of nest interiors using polyurethane (‘physical replicas’), from which 3D models were constructured using Metashape software (‘digital replicas’). We then estimated the volume and entrance area size of the digital replicas of nest interior using Metashape. To verify that the digital replicas preserve the structural characteristics of the physical replicas, we measured the volume and entrance area size of the physical replicas with Archimedes' drainage method and ImageJ, respectively. We then compared the manual measurements of the physical replicas to the values estimated from digital replicas. The estimates on the interior volume and entrance area size of 50 Asian house martin nests were nearly identical between physical and digital replicas. These results verified that the digital replicas are as reliable as the physical replicas for measuring structural characteristics of nest interior. Our 3D modelling approach allows for easy archiving as digital replicas of nest interiors endure preservation over time much better than actual nest specimens. Furthermore, digital replicas can be shared via internet and analysed for different aspects of morphometrics at any time by anyone. Overall, this tool should facilitate research on the ecology and evolution of animals in relation to nest construction.

Development, characterization, and comparison of chitosan microparticles as a carrier system for black bean protein hydrolysates with antioxidant capacity.

Peptides in black bean protein hydrolysates (BPHs) exert antioxidant capacity. However, peptides are prone to degradation during processing and digestion. Chitosan (Ch) can protect them and provide a delayed release. This work develops and compares two drying methods producing porous structured Ch microparticles (MPs) as carriers for antioxidant BPH. Ch gels were obtained by ionic gelation and dried by supercritical CO2 solvent displacement or fast-freeze-drying methods. The resulting aerogels and fast-freeze-dried MPs were structurally characterized, and their swelling and release profiles were obtained at pH 1.2 and 7.4. The antioxidant capacity of systems was determined by 2,2'-azino-bis(3-ethyl-benzthiazoline-6-sulphonic acid) (ABTS) and superoxide radical assays. The results showed BPH-Ch best complexation conditions occurring at a pH of 4.5 and a 4:1 BPH/Ch ratio. The particle size of the complex was 1047.6nm, and the entrapment efficiency and loading capacity were 28.2% and 54.3%, respectively. At pH 1.2 and 7.4, the release rate of BPH was lower in aerogel than in fast-freeze-dried MPs. Besides, entrapment BPH in Ch significantly reduced the ABTS antioxidant activity IC50 from 35.1µM Trolox equivalents (TE)/mg to 250.7 and 406.2µM TE/mg for Ch fast-freeze-dried and aerogels, respectively. Superoxide radical inhibition IC50 ranged from 74.6 to 92.9mM ascorbic acid equivalents/mg in the different samples. BPH-loaded aerogels presented lower specific surface area (94.7 vs. 138.6m2/g, p<0.05) and higher average pore size (26.4 vs. 19.8nm) than Ch aerogels. Ch aerogel is a promising carrier for delaying the release of common bean antioxidant peptides useful for developing functional foods. PRACTICAL APPLICATION: This novel system could act as an ingredient to incorporate antioxidant compounds in different formats to develop delayed-release nutraceuticals and functional foods, such as bakery, dairy products, or beverages. Along, antioxidant peptide-loaded aerogels could be used as a slow-release system for compounds acting as natural preserving antioxidants for food applications such as raw meat products or high-fat foods.

Impact analysis of particle sphericity on the properties of porous materials via particle packing method for hydrogen fuel and electrolysis cells

This study focuses on the impacts of particle's sphericity on the properties of porous materials crucial to electrochemical devices. Three-dimensional structures with spherical and cylindrical particles were generated to simulate porous granular and fibrous materials. The constructed particle geometries are as follows: a sphere and cylinders with different aspect ratios (height-to-diameter) of 0.1, 0.5, 1.0, 2.5, 5.0, 10, and 20. Every model exhibits a porosity of 0.500 ± 0.001 to exclude the effects of porosity. The structures were binarized with 200×200×200 dimensionless voxels, which were analyzed with the specific surface area, grain and pore size distributions, geometrical tortuosity, conductivity, and diffusivity across the through- and in-planes. As a result, the particle geometry significantly impacts on tortuosity, conductivity, and diffusivity, with the absolute value of Spearman's correlation coefficient of up to 1. It may imply the necessity to consider particle geometry as an ex-situ characterization for better electrochemical performance.

Facile Microwave-Assisted Growth of 3D ZnVO Nanomarbles on Graphene Oxide Nanosheets for Simultaneous Detection of Ascorbic Acid, Dopamine, and Uric Acid

Simultaneous detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA) is challenging due to close oxidation potential. These biomolecules lie in the human body and have significant roles in many psychological reactions. A slight change in the concentration of these molecules can cause serious health issues; in this context, accurate and timely detection holds significant value in clinical diagnostics. This work demonstrates the synthesis of 3D zinc nanomarbles on 2D graphene oxide sheets using a rapid and environmentally friendly microwave-assisted technique. The porous morphology with thin nanomarbles where (2 2 0) reactive sites were exposed to the environment with enhanced surface area measured 38.29 m2 g-1. The composite ZnVO/rGO has been employed on glassy carbon electrodes, resulting in superior electrocatalytic properties that enable the simultaneous detection of these analytes with wide potential gaps. Notably, the ZnVO/rGO/GCE exhibits simultaneous detection with a working range of AA (100 µM-1000 µM), DA (10 µM-100 µM), and UA (10 µM-100 µM). The detection limits were estimated to be 4.3µM, 0.7µM, and 0.32µM, respectively. The ZnVO/rGO/GCE sensor demonstrates remarkable stability, selectivity, reproducibility, and satisfactory recovery during real sample analysis. The high surface area, porous nature, and thin size of 3D nanomarbles enhance charge transportation, making it promising for electrochemical performance. This study lays the foundation for future advancements in human health monitoring by introducing a novel approach.

Reduced Graphene Oxide/Silica Based Electrode Material: Synthesis and Characterization

&lt;span lang="EN-US"&gt;Developing a Reduced Graphene Oxide (rGO) synthesis method based on rice husk as a composite electrode material with silica has garnered particular attention for designing high-quality electrode materials. This research successfully synthesized rGO-Si material from rice husk-derived activated carbon through a one-step thermal reduction process at 200 °C. This method offers a simple, efficient, cost-effective, and environmentally friendly synthesis approach. The resulting samples' morphology, surface composition, crystal structure, surface area, and pore diameter size were characterized using FE-SEM, EDX, XRD, and SAA-BET. EDX characterization results confirmed the predominance of carbon content in the samples. At the same time, the natural emergence of Si without external addition due to thermal reduction at 200 °C was an intriguing initial finding. The spherical crystal structure of silica between the wrinkled rGO layers was confirmed through FE-SEM and XRD analysis. The synergistic effect between Si and rGO significantly increased the sample's surface area, with a value of 34.17 m&lt;sup&gt;2&lt;/sup&gt;/g for the rGO sample before thermal reduction, which increased to 121.24 m&lt;sup&gt;2&lt;/sup&gt;/g after the thermal reduction process at 200 °C. This process also positively impacted the reduction in pore size of rGO-Si, with a value decreasing from 9.33 nm before thermal reduction to 4.89 nm after the thermal reduction process. The results of this study demonstrate that rGO-Si synthesized from rice husk-derived activated carbon holds great potential as a high-performance electrode material, combining the advantages of thermal reduction, natural Si content, and increased surface area for diverse applications.&lt;/span&gt;

Heterostructure of perovskite coupled graphitic carbon nitride for enhanced photodegradation under visible light

This study aimed to prepare and characterize LaFeO3 nanoparticles loaded graphitic carbon nitride (LFO/g-C3N4) photocatalyst and investigate the degradation of organic pollutants under UV and natural sunlight exposure. It is observed that LFO nanoparticles of an average size of about 67 nm were distributed on g-C3N4 sheets through chemical bonding owing to the formation of a composite. Compared to LFO and g-C3N4, composite has a good absorption ability to harvest more UV and visible light due to its large surface area and pore size. The photocatalytic studies revealed that the g-C3N4/LFO composite exhibits higher catalytic efficiency and stability for methylene blue (MB) degradation under UV and visible light. Under UV irradiation, the degradation efficiency of LFO, g-C3N4, and g-C3N4/LFO composite in synthetic wastewater was found to be around 50, 80 and 93 % with corresponding rate constants 0.05, 0.02, and 0.1 min−1 in 30 min, respectively. Under natural sunlight, the composite degraded 97 % of MB in 180 min with a rate constant of 0.016 min1. The higher photocatalytic activity of the composite was attributed to the interfacial charge transfer between LaFeO3 and g-C3N4, which are responsible for effective charge separation in the composite. Further, it has been investigated that singlet oxygen species (1O2) and hydroxyl radicals (•OH) are the main reactive species that contributed considerably to the complete degradation of MB. The nanocomposite was also demonstrated to be a stable catalyst and can be reused without any further modification.

Synthesize and Applications of Green Custard Apples leaves biosorbents for adsorptions of Sulphates and Fluorides from water

Industrial and domestic waste water release sulphur and fluoride metals into the water, thereby polluting the environment and affecting the humans and animals health. There are various techniques are available for eliminating sulphates and fluorides found in the water. Among these techniques, biosorption is a simple, cost-effective and environmentally friendly approach for removing the sulphates and fluorides from water. Biosorption is a physiochemical process that physically produces in specific biomass, enabling it to passively concentrate and bind sulphates and fluorides to its cellular structure. The custard apple leaf biosorbents are among the most effective biosorbents for the removal of fluorides and sulphates from water. In the experimental work observed that the using of 5.6g dosage of custard apple leaf biosorbents, successfully removed the sulphates and fluorides from water and a stable condition was reached. The optimal sorption of sulphur and fluoride over custard apple leaves biosorbents was achieved at a basic pH of 4-8, a concentration of 4.3g, contact time of 60minutes, temperature of 25°C, and an agitation speed of 100rpm. The particles present in custard apple leaves biosorbents have a size of 3.26µm and crystallite size 3.02nm. The surface area, pore volume and pore size of 43.68m2/g, 0.428cm3/g, and 38.64Å respectively. The adsorption of sulphates and fluorides on regenerated custard apple leaves biosorbents remained consistent for up to three cycles, but then decreased by 82.36% in the fourth cycle. The regeneration of custard apple leaf biosorbents was also calibrated, and it was observed that the custard apple leaves do not exhibit any high concentrations of changes in their performances, even after being reused for the removals of sulphates and fluorides from water. The adsorption rate move to equilibrium was due to the accessibility of lower amount of existing opening sites on the custard apple leaves biosorbents surface and also due to the binding forces between the custard apple leaves biosorbents and fluorides and sulfates molecules in the aqueous solution.