Enhancement of complex permittivity and attenuation properties of activated carbon derived from oil palm fruit fiber for microwave application

This study aimed to synthesize activated carbon (AC) from empty oil palm fruit bunch (OPEFB) fiber to enhance its complex permittivity properties by modifying the particle size and surface area via physical activation. Sample characterizations of complex permittivity were conducted using open-ended coaxial technique and a vector network analyzer. The absorption properties were analyzed using the finite element method (FEM) simulations of the transmission coefficients and the distribution of electric fields via the microstrip models. Simulations and measurements were all carried out within the range 8–12 GHz. The initial surface area of the unactivated sample was 4.02, after 700, 750, and 800 °C activation, 730.40, 814.00, and 927.01 m2/g was obtained respectively. With increased surface area, the dielectric constant and loss factor values increased and attained maximum values of 6.13 and 0.83 at 8 GHz, respectively from initial values of 3.63 and 0.52, as the surface area increased from 4.02 to 927.01 m2/g. The improved absorption properties displayed by the AC in the simulations demonstrated their capacity to attenuate X-band microwaves

Prevalence and Impacts of Psychoactive Substance Abuse amongst Undergraduate University Students in Katsina State, Nigeria

Background: Drug and substance abuse among university students is of public health concern and is becoming a global threat to the education system. This is more devastating to the academic performance of the addicts. The present study aims to assess the prevalence and impacts of psychoactive substance abuse among the university undergraduate students in Katsina State, Nigeria, and to determine the effects of such abuses on the students’ academic performance.Methods: A cross-sectional study was conducted using online survey tool (Google Form) validated by content validity and pilot study. The hyperlink to the online survey tool was shared with undergraduate students from three universities located in Katsina State via emails and social media platforms, namely WhatsApp, Facebook, and Twitter. Data collected from eligible participants were analyzed using descriptive statistics.Findings: A total of 308 students from the three universities returned the online questionnaire, of which 67.2% were men and 32.8% were women. Among the respondents, 37% admitted practicing drug and/or substance abuse. Majority of them (56.2%) were third-year students in the age range of 20-25 years.Conclusion: Drug and substance abuse among the undergraduate university students in Katsina State is common, and it cuts across both male and female students. Concerted efforts towards parental support and supervisions, social intervention programs, and campus-based prevention and supported programs against drug and substance abuse should be encouraged

Influence of tartaric acid concentration on structural and optical properties of CuSe nanoparticles synthesized via microwave assisted method

The influence of chelating agent on structural and optical properties of copper selenide nanoparticle has been the subject of ongoing debate in copper selenide based material research. In this project we developed a straightforward microwave irradiation technique for the synthesis of copper selenide nanoparticles. Copper selenide nanoparticles were successfully synthesized using CuCl2·2H2O and Na2SeO3 as copper and selenium sources respectively while, the reducing and chelating agents were hydrazine hydrate and tartaric acid respectively. The effect of concentration of tartaric acid on structural and optical properties of CuSe NPs were investigated. The as-prepared product were characterized by means of an X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron spectroscopy (FESEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), UV–visible absorption spectroscopy (UV–Vis.), Raman spectroscopy and photoluminescence spectroscopy (PL). XRD results reveal a hexagonal (Klockmannite) crystal structure with size in the range between 73.10 nm and 16.10 nm. The band gap of the as-prepared CuSe NPs were found to increase between 1.80 eV and 2.10 eV. The wavelength of the maximum PL emission was at 600 nm with 400 nm excitation wavelength. Three characteristics vibrational modes belonging to CuSe NPs were detected in the Raman spectra. Therefore, the results obtained in this study provide a new pathway of understanding the effect of tartaric acid concentration on structural and optical properties of CuSe NPs and can explain the use of this novel product as a potential candidate for optoelectronic and solar cell applications

Influence of chelating agents on structural, optical, and electromgnetic interference properties of copper selenide nanoparticles synthesized via microwave-assisted method

Recently, group II-VI binary semiconductor nanomaterials including copper selenide (CuSe), have garnered increased attention due to their remarkable properties that differ significantly from their bulk counterparts, as their functions are highly dependent on particle size, shape, and surface properties. To tune the overall properties of this nanoparticle, various surface modifications are required, such as capping the surface with organic, inorganic, and polymer-based chelating agents which can be used in various applications. In this work, CuSe nanoparticles were synthesized using a simple, low-cost, and environmentally friendly microwave method. Optimization of synthesis conditions such as microwave power, irradiation time, hydrazine hydrate concentration, and copper concentration was carried out to obtain a pure single-phase CuSe nanoparticle. Singlephase CuSe nanoparticles were obtained at 380 W microwave power, 20 minutes of irradiation time, 3 ml of hydrazine hydride, and 0.9:1 copper to selenium molar ratio. The effect of chelating agent concentrations on the structural, morphological, and optical properties of CuSe nanoparticles was fully investigated. Six different chelating agents were used: tartaric acid (TA), ethylenediaminetetraacetic acid (EDTA), citric acid (CA), cetyl ammonium bromide (CTAB), polyvinylpyrrolidone (PVP), and polyethylene glycol (PEG). X-Ray Diffraction (XRD) analysis revealed that all samples formed a pure single-phase hexagonal (Klockmannite) crystal structure. The XRD analysis result is in agreement with the energy dispersive X-ray (EDX) and Raman analysis. At various concentrations of TA, EDTA, CA, CTAB, PVP, and PEG, the average crystallite size estimated using Scherer’s method decreased from 73.10 to 16.10 nm, 73.10 to 16.80 nm, 73.10 to 18.20 nm, 73.10 to 43.60 nm, 73.10 to 14.00 nm, and 73.10 to 21.20 nm respectively. The Williamson-Hall method revealed an estimated crystallite size that is comparable to Scherer's method. The atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM) analysis agree with the obtained XRD results. At various concentrations of TA, EDTA, CA, CTAB, PVP, and PEG, the optical band gap increased from 1.80 to 2.10 eV, 1.80 to 2.20 eV, 1.80 to 2.25 eV, 1.80 to 2.30 eV, and 1.80 to 2.24 eV, respectively. This is attributed to the decrease in particle size of the final product. Besides, photoluminescence (PL) maximum emission for all the samples was centered at 610 nm. The PL intensity was found to increase with increasing chelating agent concentrations in all samples. Other than that, the effect of particle size of CuSe NPs as nanofiller loaded in the PVA polymer matrix on dielectric properties and electromagnetic interference shielding effectiveness (EMI SE) was investigated. The result showed that the dielectric constant, loss factor and loss tangent increases with the decrease in CuSe nanofiller size. This is because smaller particles fill the matrix evenly, forming a chain-like network in the PVA matrix. Moreover, the EMI SE measurement results showed that reflection loss (SER), absorption loss (SEA), and total interference shielding (SET) decreases with an increase in frequency, which is attributed to the impedance mismatch of the EM waves as the applied frequency is increased from 8 to 12 GHz. Additionally, the nanocomposites exhibited a high absorption potential for electromagnetic waves (SEA), but a significant portion of the EM wave was also reflected (SER). The contribution of SER and SEA to SET increased as the size of the CuSe nanofiller is decreased. The nanocomposites showed the SET is higher than the target value of 20 dB. Thus, the results show that incorporating CuSe NPs of various sizes into a PVA polymer matrix significantly improves the total shielding effectiveness of EM waves, implying that the prepared nanocomposites can be used as lightweight, flexible, and low-cost material for electromagnetic interference shielding applications

Biodiesel production from castor oil and analysis of its physical properties

Biodiesel is a biodegradable, renewable energy and efficient substitution fuel which can fulfill energy security needs without sacrificing engine performance. Biodiesel fuels were prepared from vegetable oil of castor beans and its physical properties such as viscosity, flash point and pour point were studied. The crude castor oil was purified and trans-esterified. Transesterification reaction is most widely used method for biodiesel production, in which the triglycerides in the oil reacts with monohydric alcohol. 200 ml of the castor oil was measured and pre-heated to 70 oC using hot magnet stirrer with thermometer. 1.5 ml citric acid was added to the heated oil sample and continuously stirred for 15 minutes at 70 oC. 4g of 8 % KOH was then added to the oil and continuously heated and stirred for 15 minutes at 70 oC. The mixture was then transferred to the vacuum oven where it was heated at 85 oC for 30 minutes. Similarly, 2g of silicon reagent was added while it was being heated and stirred. after 30 minutes the temperature was increased to 85 oC and 4g of activated carbon was added to each 100 ml of the oil sample, heated and stirred for 30 minutes and the mixture was separated using filter paper. At 30, 60 and 90 oC, the viscosity of crude, purified and transesterified castor oil were found to be (64, 52, 50 mpa.s), (47, 43, 37 mpa.s) and (38, 35 and 30 mpa.s) respectively. This shows that, trans-esterified castor oil has viscosities within similar range with the crude biodiesel oil for all the varying temperatures, indicating that viscosity is major reason why oils and fats are trans-esterified to biodiesel

Antibiotics self-medication among undergraduate pharmacy students in Northern Nigeria

Introduction: The burden of antibiotic self-medication (ASM) is increasing and becoming a global health threat due to antibiotics resistance. However, little is known about ASM among undergraduate pharmacy students who are the future custodians of medicines including antibiotics. Therefore, this study aims to develop, validate and utilize an online survey tool to investigate the prevalence of ASM among undergraduate pharmacy students in Northern Nigeria. Methods: A cross-sectional online survey form was developed, validated by face validity, content validity, and pilot study. The hyperlink to the online survey form was shared with undergraduate pharmacy students in northern Nigeria via WhatsApp, Facebook, and Twitter. Data were collected from eligible participants and analyzed using descriptive statistic. Results: A total of 217 students responded to the online survey, with a completion rate of 100%. Of the total number of respondents, 200 (92.2%) reported practicing ASM at least once in their lifetime. The major reasons for ASM were previous knowledge (40.4%) and having no time to see a doctor or pharmacist (27.5%). Amoxicillin (32.6%), Amoxicillin/Clavulanic acid (32.1%), Ampicillin/Cloxacillin (21.7%) and Ciprofloxacin (22.6%) were the most commonly implicated antibiotics in ASM. Cough, diarrhea, typhoid, and wound were the most frequently involved conditions. Patent medicine vendors (75.4%) and community pharmacies (29.4%) were the common source of antibiotics subjected to ASM. Conclusion: A research tool to assess ASM among undergraduate pharmacy students has been developed, validated and utilized. The prevalence of ASM is high among undergraduate pharmacy students in Northern Nigeria. Interventions to improve knowledge and awareness on ASM are needed among undergraduate pharmacy students to ensure antibiotic stewardship

Augmenting pomelo juice quality through membrane-based clarification and bioactive compounds recovery

The presence of impurities, microorganisms, enzymes, suspended solids, and impurities in unclarified pomelo juice negatively affected the quality and shelf-life of the product in the food industry. The objective of this study focuses on the clarification of fresh pomelo juice using an ultrafiltration (UF) process. The study examined the influence of the operating pressure (OP) on the various quality attributes of pomelo juice, such as pH, total soluble solids (TSS), turbidity, color, total phenolic content (TPC), ascorbic acid content (AAC) and fouling mechanisms and permeate flux (J) behavior. To perform the clarification of pomelo juice, a 100 kDa membrane (polymeric) was used in a dead-end system, and the process was carried out in batch mode at OP values of 1.0, 1.5, 2.0, 2.5 and 3.0 bar. The findings revealed that increasing OP led to higher flux during ultrafiltration with limiting pressure (Plim). The limiting pressure (Plim) was anticipated to be beyond 3.0 bar due to the enzymatic pretreatment. The primary fouling mechanism during the clarification process was total pore blocking. After filtration, the resulting juice showed a significant reduction in turbidity of over 97, while TSS was lowered by 7–17 compared to fresh juice. The pomelo juice was efficiently clarified while the pH remained stable at ∼3.8. The clarified juice showed a minor decline of 10.1–13.9 in TPC and a 10.8–16.7 reduction in AAC compared to the fresh unclarified juice. In conclusion, a pressure of 3.0 bar is recommended for conducting the ultrafiltration process in order to attain desirable flux behavior and optimum properties of the juice

A novel oil palm frond magnetic biochar for the efficient adsorption of crystal violet and sunset yellow dyes from aqueous solution: synthesis, kinetics, isotherm, mechanism and reusability studies

Abstract This study presented a facile synthesis route via the precipitation method for the production of magnetic biochar from oil palm frond (OPF). The physicochemical characteristics including surface, functional, and magnetic properties of the synthesized magnetic biochar revealed that the surface morphology, porosity, and magnetic properties enhanced its adsorption capacity for the removal of crystal violet (CV) and sunset yellow (SY) from aqueous solution. The saturation magnetization of OPF biochar was found to be 8.41 emu/g, coercivity (Hc) of 83.106 G, and retentivity (Mr) of 1.475 emu/g which implies that OPF magnetic biochar can be facilely separated from aqueous solution. The result also demonstrated superparamagnetic properties which provided suitable magnetic responsive characteristics to an external magnetic field. The interactive effect of the operational conditions of pH, adsorbent dosage, initial concentration, and temperature was investigated in a batch adsorption study using the central composite design (CCD) of the response surface methodology (RSM). It was indicated that an increase in adsorbent dosage to 1.0 g/L at a lower initial concentration (50 ppm) conducted at 20 °C favoured optimum removal of CV and SY at pH 11 and 4, respectively. The Langmuir isotherm model with maximum adsorption capacity ( $$q_{\max }$$ q max ) of 149.03 and 342.47 mg/g was achieved for CV and SY dyes, respectively. The kinetic data proved to be best fitted to the pseudo-second-order kinetic model. Thermodynamic parameters revealed spontaneous and endothermic reactions. The suitability and sustainability of the magnetic biochar were enhanced by its regeneration potential for effective adsorption of CV and SY after 5 cycles which indicates its outstanding reusability. Hence, OPF magnetic biochar exhibited prospective application for the removal of dyes from wastewater

Effects of irradiation time on the structural, elastic, and optical properties of hexagonal (wurtzite) zinc oxide nanoparticle synthesised via microwave-assisted hydrothermal route

Zinc oxide (ZnO) is a vital nanomaterial highly valued in electronics and optoelectronics due to its remarkable multifunctional properties. This study prepared ZnO nanoparticles using a simple hydrothermal microwave process. The influence of irradiation time on the structural, elastic and optical properties of the ZnO nanoparticles was investigated. X-ray diffraction (XRD) analysis confirmed the hexagonal (wurtzite) structure of the ZnO nanoparticles. In addition, various XRD profile analysis techniques were used in this study, including Scherer method, strain size plot method, Halder–Wagner method, Monshi–Scherer method, and Williamson–Hall method consisting of a uniform deformation model, a uniform stress density model and a uniform deformation energy density model. The estimated mean crystallite size was found to be at 43.53–56.08 nm. Furthermore, atomic force microscopy and transmission electron microscopy were used to investigate the average particle size of the ZnO nanoparticles at different irradiation times. The results were consistent with the mean crystallite size calculated using the X-ray diffraction peak profile analysis techniques. Furthermore, a decrease in the energy band gap estimated by diffuse reflectance spectroscopy was observed, transitioning from 3.32s to 3.29 eV with increasing irradiation time. This observation was confirmed by the distinct and unique ultraviolet photoluminescence emission peaks of the synthesized ZnO nanoparticles, supporting the results of the diffuse reflectance analysis. Based on the presented results, it can be concluded that the X-ray diffraction peak profiling technique is a practical approach for determining the average crystallite size of ZnO nanoparticles prepared using the microwave hydrothermal technique and that it can be used for size-dependent applications