•Three adsorbents, sodium hydroxide activated carbon, calcium alginate and a composite of both were prepared.•Effect of adsorbent dosage, pH, time, temperature and initial concentration of methylene ...blue were studied.•Thermodynamic studies show the spontaneous and endothermic nature of overall adsorption process.
Three adsorbents, calcium alginate beads (AB), sodium hydroxide activated carbon based coconut shells (C), and calcium alginate/activated carbon composite beads (ACB) were prepared. Their textural properties were characterized by N2-adsorption at −196°C and scanning electron microscopy. The porosity, surface area and total pore volume of C>ACB>AB, but AB adsorbent was more acidic function groups more than the other adsorbents. Adsorption experiments were conducted to examine the effects of adsorbent dosage, pH, time, temperature and initial concentration of methylene blue. Methylene blue adsorption on C, AB and ACB was observed at pH>6 to avoid the competition of H+. The amount of dye adsorbed increases as the adsorbent dosage increase. Adsorption of dye follows pseudo-second order mechanism. Thermodynamic studies show spontaneous and endothermic nature of the overall adsorption process.
•Short-staple microfibers (SSM) from different sources were fabricated via a wet rotate-spinning technique.•SSMs were employed for removal Cr(IV) from aqueous solution for the first time.•Effects of ...pH value, fiber dose on the adsorption efficiency of Cr(VI) were investigated.•Physical, chemical, kinetics and thermodynamic properties were studied and evaluated.
Short staple microfibers (SSM) based on chitosan (CS) or silk fibroin (SF) were fabricated via the wet-rotate-spinning technique and employed to adsorb hexavalent chromium from aqueous solution. Adsorption efficiencies, physicochemical and morphological properties of CS and SF-SSM were systematically investigated and evaluated before and after adsorption of Cr(VI) using different techniques like ATR-FTIR, TGA, XRD, XPS, and SEM. CS and SF-SSM showed removal efficiency (>90 %) toward Cr(VI) ions. Pseudo-second order kinetic and Langmuir isotherm models could describe the Cr(VI) ions uptake process. Considering the inexpensive, sustainability and higher adsorption capacity of CS and SF-SSM hold great promising applications as natural adsorbent materials for removing different hazardous metals from aqueous medium.
The present investigation deals with preparation of three different adsorbent materials namely; potassium hydroxide activated carbon based apricot stone (C), calcium alginate beads (G) and calcium ...alginate/activated carbon composite beads (GC) were used for the removal of arsenic. The prepared adsorbent materials were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), N2-adsorption at −196°C and point of zero charge. From the obtained results, it was found that the porosity, surface area and total pore volume of the adsorbent material C>GC>G respectively, however, the G adsorbent has more acidic function group than the other adsorbents. The influence of pH, time, temperature and initial concentration of arsenic(V) were studied and optimized. GC exhibits the maximum As(V) adsorption (66.7mg/g at 30°C). The adsorption of arsenic ions was observed to follow pseudo-second order mechanism as well as the thermodynamic parameters confirm also the endothermic spontaneous and a physisorption process.
Functional materials have long been studied for a variety of environmental applications, resource rescue, and many other conceivable applications. The present study reports on the synthesis of ...bismuth vanadate (BiVO
) integrated polyaniline (PANI) using the hydrothermal method. The topology of BiVO
decked PANI catalysts was investigated by SEM and TEM. XRD, EDX, FT-IR, and antibacterial testing were used to examine the physicochemical and antibacterial properties of the samples, respectively. Microscopic images revealed that BiVO
@PANI are comprised of BiVO
hollow cages made up of nanobeads that are uniformly dispersed across PANI tubes. The PL results confirm that the composite has the lowest electron-hole recombination compared to others samples. BiVO
@PANI composite photocatalysts demonstrated the maximum degradation efficiency compared to pure BiVO
and PANI for rhodamine B dye. The probable antimicrobial and photocatalytic mechanisms of the BiVO
@PANI photocatalyst were proposed. The enhanced antibacterial and photocatalytic activity could be attributed to the high surface area and combined impact of PANI and BiVO
, which promoted the migration efficiency of photo-generated electron holes. These findings open up ways for the potential use of BiVO
@PANI in industries, environmental remediation, pharmaceutical and medical sectors. Nevertheless, biocompatibility for human tissues should be thoroughly examined to lead to future improvements in photocatalytic performance and increase antibacterial efficacy.
Aluminum matrix composites reinforced with reduced graphene oxide (rGO) and hybrid of carbon nanotube (CNT) and rGO are fabricated by solution coating powder metallurgy process. The hardness, wear ...resistance and coefficient of thermal expansion (CTE) of the reinforced aluminum composites and the associated microstructural changes with rGO range (0.2–0.6 wt%) and hybrids of 0.2 wt% CNT–rGO at different ratios have been investigated. The intensive microstructural observations show that rGO is adsorbed on Al particles and uniformly distributed in the Al matrix composites. The hardness values of the composites increase significantly with rGO reinforcement exhibiting the maximum hardness at 0.4 wt% rGO. Compared with the hybrid composites CNT–rGO/Al counterparts fabricated by the same route and wt. percent of 0.2, the hardness values in the hybrid CNT–rGO increase considerably. Similar to the hardness, the results of wear tests also exhibit corresponding variation in the values of the wear rates. The improvement in the wear resistance of the hybrid CNT–rGO /Al composite is pronounced in this work. Whereas the rGO reinforcements decrease significantly the wear rate of the aluminum-base by 98%, the wear resistance of the corresponding hybrid CNT–rGO is significantly higher than that of the preceding composites. Maximum CTE reduction of 28% was recorded for hybrid CNT–rGO (1:1) reinforced composite.
Graphic Abstract
•Schizophyllan (SPG) triple helical biopolymer was used for first for preparation of silver nanoparticles (Ag-NPs).•SPG used as reducing and stabilizing agent for Ag-NPs.•SPG/silver nanocomposite was ...characterized by TEM, DLS, UV–vis spectra, FTIR, TGA, and XRD.•Mouse fibroblast cell line (NIH-3T3) and human keratinocyte cell line (HaCaT) were systematically evaluated the cytotoxicity of nanocomposite SPG/Ag-NPs.
Silver nanoparticles (Ag-NPs) have been successfully prepared with a simple and “green” chemical reduction method. Triple helical schizophyllan (SPG) was used for the first time as reducing and stabilizing agents. The effect of temperature, silver nitrate/schizophyllan concentrations, pH of the reactions medium and the reaction time were investigated. The obtained schizophyllan/Ag-NP was characterized by UV–vis spectroscopy, TEM, DLS, X-ray diffraction, TGA, and ATR-FTIR. The results revealed that, Ag-NPs attached to SPG through a strong non-covalent interaction, leading to good dispersion of Ag-NPs with a diameter of 6nm within the biopolymer matrix. By increasing the pH of the reaction medium, the triple helical structure of SPG was partially broken. The SPG/AgNP nanocomposite was non-toxic for mouse fibroblast line (NIH-3T3) and human keratinocyte cell line (HaCaT).
This paper reports synthesis, properties and gas sensing applications of ZnO nanoflowers and CdO–ZnO nanorices prepared by hydrothermal process. The morphological characterizations confirmed the ...formation of well-defined nanoflowers and nanorices structures for ZnO and CdO–ZnO nanomaterials, respectively. The structural properties revealed the wurtzite hexagonal phase of the synthesized materials. The sensor devices based on ZnO nanoflowers and CdO–ZnO nanorices were fabricated and tested towards various gases including ethanol, methanol, ammonia, carbon monoxide, methane and formaldehyde. The fabricated gas sensor based on CdO–ZnO nanorices exhibited a high response (34.5) towards 300 ppm formaldehyde gas at 350 °C compared to ZnO nanoflowers (14.5) under the same experimental conditions. The response and recovery times for ZnO nanoflowers-based sensor were~9.8 s and ~6 s while for CdO–ZnO based sensor, these were ~10s and ~6s, respectively. A rapid response (34.5) for CdO–ZnO nanorices based formaldehyde gas sensor was observed as compared to other gases such as ammonia (12.3), methanol (16.5), ethanol (20), carbon monoxide (16.3) and methane (12.4), which confirm the high-selectivity towards formaldehyde gas. Finally, a plausible formaldehyde gas sensing mechanism is proposed.
•ZnO nanoflowers and CdO–ZnO nanorices were hydrothermally synthesized and characterized.•HCHO gas sensor responses of ZnO nanoflowers and CdO–ZnO nanorices based sensors were compared.•CdO–ZnO nanorices based sensor exhibited a high response as compared to ZnO nanoflowers.•Response and recovery times for ZnO nanoflowers and CdO–ZnO based sensors were ~9.8 s, ~6 s and ~10s and ~6s, respectively.
Environmental pollution is steadily rising and is having a negative influence on all living things, especially human beings. The advancement of nanoscience in recent decades has provided potential to ...address this issue. Functional metal oxide nanoparticles/nanofibers have been having a pull-on effect in the biological and environmental domains of nanobiotechnology. Current work, for the first time, is focusing on the electrospinning production of Zr
Sn
TiO
/SnO
ceramic nanofibers that may be utilized to battle lethal infections swiftly and inexpensively. By using characterizations like XRD, FT-IR, FESEM, TEM, PL, and UV-Vis-DRS, the composition, structure, morphology, and optical absorption of samples were determined. The minimum inhibitory concentration (MIC) approach was used to investigate the antibacterial activity. Notably, this research indicated that nanofibers exert antibacterial action against both Gram-positive and Gram-negative bacteria with a MIC of 25 µg/mL. Furthermore, negatively charged
was drawn to positively charged metal ions of Zr
Sn
TiO
/SnO
, which showed a robust inhibitory effect against
. It was interesting to discover that, compared to pure TiO
, Zr
Sn
TiO
/SnO
nanofibers revealed increased photocatalytic activity and exceptional cyclability to the photodegradation of Rhodamine B. The composite completely degrades dye in 30 min with 100% efficacy and excellent (97%) reusability. The synergetic effects of Zr
Sn
TiO
and SnO
may be responsible for increased photocatalytic and bactericidal activity.
Acceleration-based sensors are widely used in indicating the severity of damage caused to structural buildings during dynamic events. The force rate of change is of interest when investigating the ...effect of seismic waves on structural elements, and hence the calculation of the jerk is necessary. For most sensors, the technique used for measuring the jerk (m/s
) is based on differentiating the time-acceleration signal. However, this technique is prone to errors especially in small amplitude and low frequency signals, and is deemed not suitable when online feedback is required. Here, we show that direct measurement of the jerk can be achieved using a metal cantilever and a gyroscope. In addition, we focus on the development of the jerk sensor for seismic vibrations. The adopted methodology optimized the dimensions of an austenitic stainless steel cantilever and enhanced the performance in terms of sensitivity and the jerk measurable range. We found, after several analytical and FE analyses, that an L-35 cantilever model with dimensions 35 × 20 × 0.5 (mm
) and a natural frequency of 139 (Hz) has a remarkable performance for seismic measurements. Our theoretical and experimental results show that the L-35 jerk sensor has a constant sensitivity value of 0.05 ((deg/s)/(G/s)) with ±2% error in the seismic frequency bandwidth of 0.1~40 (Hz) and for amplitudes in between 0.1 and 2 (G). Furthermore, the theoretical and experimental calibration curves show linear trends with a high correlation factor of 0.99 and 0.98, respectively. These findings demonstrate the enhanced sensitivity of the jerk sensor, which surpasses previously reported sensitivities in the literature.
Solar cells based on lead-free perovskite have demonstrated great potential for next-generation renewable energy. The SCAPS-1D simulation software was used in this study to perform novel device ...modelling of a lead-free perovskite solar cell of the architecture ITO/WS
/CH
NH
SnI
/P3HT/Au. For the performance evaluation, an optimization process of the different parameters such as thickness, bandgap, doping concentration, etc., was conducted. Extensive optimization of the thickness and doping density of the absorber and electron transport layer resulted in a maximum power-conversion efficiency of 33.46% for our designed solar cell. Because of the short diffusion length and higher defect density in thicker perovskite, an absorber thickness of 1.2 µm is recommended for optimal solar cell performance. Therefore, we expect that our findings will pave the way for the development of lead-free and highly effective perovskite solar cells.
PDF
