Showing papers by "Muhammad Younas published in 2023"

Aquaporin‐Based Biomimetic Membranes for Low Energy Water Desalination and Separation Applications

Abstract: The emergence of biomimetic materials developed using nature's inspiration and biological domains can drive a paradigm shift in the design and operation of future‐generation materials in separation applications. In recent years, biomimetic membranes have drawn interest of many researchers for water treatment applications. Among the biomimetic membranes, protein‐based membranes, specifically those synthesized by aquaporin, have received much attention in recent years due to their high osmotic water permeability and excellent ability to remove small molecules, thereby overcoming the trade‐off between the water flux and the contaminant's rejection. The separation efficiency and fouling properties are significantly improved by taking advantage of the strategies evolved in nature. This review provides a comprehensive overview of the state‐of‐the‐art aquaporin‐based biomimetic membranes (ABMs), mainly focusing on their synthesis, characterization, and performance as selective layer in composite membranes for reverse osmosis, nanofiltration, and forward osmosis for water desalination. Fabrication methods and characterization techniques of ABMs and their performance in water desalination are also reviewed, while the main obstacles for their successful commercial viability in wastewater treatment are provided. The applications of ABMs in various separation processes other than water desalination and their potential market are presented to inspire future researchers in this versatile area.

Role of Plasmonic Nanoparticles for Oxygen and Hydrogen Evolution Reactions in Photoelectrochemical Water Splitting

Abstract: Monoclinic scheelite phase of n-type bismuth vanadate (BiVO4) as a solar-driven catalyst-based photoanode is emerging as an optimistic approach for efficient photoelectrochemical water splitting because of features such as maximum light harvesting potential in visible spectrum, nontoxicity, earth abundance and stability under electrochemical conditions. The photoelectrochemical cell is a coherent and eco-friendly technique to convert solar energy into a renewable energy source like hydrogen with zero carbon emissions. Here we fabricated nanocomposite-based photoanodes RGO/CNT/BiVO4, RGO/CNT/Ni/BiVO4, RGO/CNT/Cu/BiVO4 and RGO/CNT/Ni/Cu/BiVO4 by layering reduced graphene oxide (RGO) and carbon nanotubes (CNTs) to act as a transmission channel for fast transport of electrons with non-noble electrocatalyst nickel (Ni) and copper (Cu) nanoparticles and visible driven photoactive bismuth vanadate (BiVO4) nanomaterial on fluorine-doped tin oxide by using electrodeposition and the drop casting method. The absorption edge was analyzed using ultraviolet–visible spectroscopy and Tauc plots, which clearly indicated a decreasing trend in the bandgap of BiVO4, thereby increasing the absorption spectrum with improved charge transfer rate. To scrutinize the proficiency of the electrochemical reaction during water splitting for hydrogen evolution reaction and oxygen evolution reaction of photoanodes, electrochemical testing was done using linear sweep voltammetry, which distinctly showed that the fabricated photoanode RGO/CNT/Ni/Cu/BiVO4 possessed high photo-response at an overpotential of 190 mV, with a lower Tafel slope of 119 mV dec−1. © 2023 Society of Chemical Industry (SCI).

Rapid Synthesis of Nickel-Iron-oxide (NiFeOx) Solid-solution Nano-rods Thin Films on Nickel Foam as Advanced Electrocatalyst for Sustained Water Oxidation

Abstract: The development of earth-rich, noble-metal-free, and highly electroactive catalysts to accelerate the oxygen evolution reaction (OER) is a formidable challenge for the establishment of water-splitting technologies. Here, a solid-solution nickel-iron oxide (NiFeOx) electrocatalyst is readily grown on Ni-foam (NF) substrate by a rapid and economical aerosol-assisted chemical vapor deposition process. In particular, the NiFeOx thin film fabricated in forty minutes acquires a distinctive nano-rods structure and proves to be stable and efficient for OER in alkaline solution. It is shown that the catalyst needs a low over-potential of 226 mV to reach the typical current density of 10 mAcm-2 and it can approach to a remarkable current density level of 1000 mAcm-2 by taking a slightly more over-potential of 139 mV. The small Tafel slope of 64 mv.dec-1 and splendid electrochemical stability of 40 hours at high current densities outperform many known FeNi-based anodes as well as commercial IrO2 and RuO2. The unique structure of the thin film offers many electroactive sites and high surface area in combination with an improved electrical conductivity of NF, which is believed to play an imperative role in the excellent activity of the catalyst. The cost-effective and simple strategy to fabricate NiFeOx nano-fibrous is very attractive for the development of electrocatalysts for water splitting.

Effects of Graphite Flakes on the Material and Mechanical Properties of Polystyrene Membranes

Abstract: The use of polymer composite membranes has been widely increased to improve the mechanical and material properties. In this research, graphite flakes are used as nanofiller in polystyrene (PS) membrane to improve hydrophobicity, moisture blocking capacity, thermal stability, tensile strength, and gas separation ability. The membranes are prepared by a solution casting technique and are characterized by fourier transformation infrared spectroscopy, X-ray diffractometry, scanning electron microscope, thermal gravimetric analysis, water contact angle (WCA), moisture transmission rate (MTR), and mechanical testing. The prepared membranes are also tested to determine the O2 and N2 permeability and O2/N2 selectivity. The quantity of graphite flakes is varied from 0–1.0 wt% of PS. 0.7 wt% graphite-filled PS has shown the best results among all the prepared samples. The WCA of the PS membrane is increased from 97.3 to 114.803°, which shows that graphite flakes are well-suited to increase the hydrophobicity of the PS membrane. The MTR of 0.7 wt% graphite-filled PS shows that the membrane is well-suited for moisture blocking and also showed better thermal stability. Graphite flakes are also found suitable for increasing the tensile strength of the membrane. Also, the highest O2/N2 selectivity is achieved for 0.7 wt% graphite-filled membranes, which makes them suitable for gas separation operation. Furthermore, the potential application of graphite-filled PS membranes is also presented.

Effectual Water Oxidation Reinforced by Three-Dimensional (3D) MnO: A Highly Sustainable Electrocatalyst

Abstract: Fabricating highly effective, durable, eco-friendly, and low-cost electrocatalysts are challenging in renewable energy applications. Manganese(II) oxide (MnO), an oxygen evolution reaction (OER) catalyst, is an appealing contender in electrocatalytic water oxidation. Herein, we report the fabrication of single-phase MnO films over nickel foam (NF) as 3D electrode materials via a facile aerosol-assisted chemical vapor deposition (AACVD). HR-TEM confirms the nanoscale composition and polycrystalline structure, while the cauliflower-like morphology was observed under FE-SEM supported by EDX for conforming elemental composition. XRD and XPS analysis proved their chemical structure and oxidation states. The electrochemical investigations of MnO films prepared at 60 min revealed excellent OER performance in 1.0 M KOH. The benchmark decade current density was achieved just at an overpotential of 150 mV, whereas at an overpotential of 430 mV, Mn@NF-60 showed a maximum current density of 1158 mA cm–2 which is 4–6-folds better than its counterparts. The large electrochemical surface area (154 cm2), lower Tafel slope (80.93 mV/dec), and charge transfer resistance (18 Ω), excellent durability throughout extended chronopotentiometry analysis, and fast electron transfer reaction kinetics for OER comprehend Mn@NF-60 as an effectual electrocatalyst. These attributes of a single-phase MnO@NF-60 are credited to ample electroactive sites that enhance electron transfer processes. This study offered highly active single-phase metal oxide thin films by AACVD as 3D electrode materials for plentiful electrocatalytic applications.

The Role of the Ferroelectric Polarization in the Enhancement of the Photocatalytic Response of Copper-Doped Graphene Oxide–TiO2 Nanotubes through the Addition of Strontium

Abstract: To evaluate the potential role of in situ formed Sr–Ti–O species as a ferroelectric component able to enhance the photocatalytic properties of an adjacent TiO2 semiconductor, Cu-doped/graphene oxide (GO)/TiO2 nanotubes (TiNTs) composites (with 0.5 wt % Cu and 1.0 wt % GO) have been synthesized while progressive amounts of strontium (up to 1.0 wt %) were incorporated at the surface of the composite through incipient wetness impregnation followed by post-thermal treatment at 400 °C. The different resulting photocatalytic systems were then first deeply characterized by means of N2 adsorption–desorption measurements, X-ray diffraction (XRD), UV–vis diffuse reflectance (UV–vis DR), Raman and photoluminescence (PL) spectroscopies, and scanning electron microscopy (SEM) (with energy-dispersive X-ray (EDX) spectroscopy and Z-mapping). In a second step, optimization of the kinetic response of the Sr-containing composites was performed for the formic acid photodegradation under UV irradiation. The Sr-containing Cu/GO/TiNT composites were then fully characterized by electrochemical impedance spectroscopy (EIS) for their dielectric properties showing clearly the implication of polarization induced by the Sr addition onto the stabilization of photogenerated charges. Finally, a perfect correlation between the photocatalytic kinetic evaluation and dielectric properties undoubtedly emphasizes the role of ferroelectric polarization as a very valuable approach to enhance the photocatalytic properties in an adjacent semiconductor.

Inhibition of hydrogen evolution and corrosion protection of negative electrode of lead-acid battery by natural polysaccharide composite: Experimental and surface analysis

Abstract: The investigated research illustrates the synthesis of composite polymer (GG-VA) using natural polysaccharide (Guar Gum/GG) and vinyl acetate (VA) and screening their inhibitive performance for the hydrogen gas evolution and corrosion inhibition of lead-acid battery negative electrode, i.e., Pb in 5.0 M H2SO4. The developed inhibitor is an environmentally friendly biological molecule and has been used for lead acid batteries for the first time as an additive. The methodology used to evaluate GG-VA inhibitive performance included hydrogen evolution and electrochemical methods, i.e., EIS and PDP. The corrosion inhibition performance of GG-VA is 88.57 %. The Pb surface was screened for GG-VA adsorption via SEM and AFM. The experimental data confirmed the reduction in hydrogen gas evolution with the addition of GG-VA. The EIS result supports the increasing Rct values with the rising GG-VA amount corresponding to the GG-VA adsorption. PDP data reveals the mixed inhibition action and reduction in icorr values with the addition of GG-VA. The increasing temperature causes a decrease in GG-VA performance. GG-V adsorption over the Pb surface was best described by Langmuir isotherm. The Ea data reveals the increase in the energy barrier for corrosion reaction and H2 gas evolution in the presence of GG-VA. The SEM and AFM support the adsorbed layer of GG-VA formation at the Pb surface.

Corrosion and bacterial growth mitigation in the desalination plant by imidazolium based ionic liquid: Experimental, Surface and molecular docking analysis

Abstract: The desalination plants wieldy used CuNi alloys. However, it faces a fundamental corrosion problem in a 3.5% NaCl solution containing sulfide ions. In this research, we have examined ionic liquid's corrosion and bacterial inhibition activity, i.e., 1-Dodecyl-3-methylimidazolium iodide (IMD-IL). The obtained data from weight loss and electrochemical reveals the corrosion inhibitive performance of IMD-IL is 96.8% at 100 mg/L. The EIS suggests increasing the charge transfer resistance and film resistance with increasing IMD-IL amount, supporting the inhibitive action of IMD-IL molecules. The biological activity results reveal the deactivation of SRB action after the addition of IMD-IL molecules. The SEM and EDX studies support the IMD-IL adsorption onto the CuNi surface. The molecular docking results confirmed that IMD-IL could bind the cytochrome c, inhibiting its activity and thereby interrupting the electron transport pathway between bacteria and the CuNi.

Documentation of trypanosoma evansi in captive tigers and lions in punjab (2016–2018), pakistan

Abstract: Abstract: Trypanosoma evansi is an important hemoparasite of a variety of animal species worldwide. This parasite is a threat to the health of domestic animals as well as wild animals, particularly those managed in captivity. The current study investigated the presence of T. evansi in captive tigers (Panthera tigris tigris) and lions (Panthera leo) in Pakistan. In total, 24 blood samples from 11 tigers and 3 lions (n = 14) were collected during the course of roughly 3 yr (2016–2018). Eighteen samples were subjected to both microscopic and molecular evaluation for the presence of T. evansi; the remaining 6 samples were processed for PCR only. Of the 18 samples tested by both methods, 3 (16%) and 8 (44%) were positive by microscopy and PCR, respectively. This highlights the higher sensitivity of PCR over microscopy for detection of trypanosomes. Of the 24 total samples evaluated by PCR, 12 (50%) were positive. The three sequences obtained showed 99% identity with variant surface glycoprotein genes of the different isolates of T. evansi. The sensitivity, specificity, positive predictive value, and negative predictive value of microscopy in identifying T. evansi was 37.5, 100, 100, and 66.7%, respectively, considering PCR as the gold standard. We recommend rigorous monitoring of captive tigers and lions for hemoparasites, particularly in winter and early spring in areas with high infection rate of this parasite, preferably via PCR.

Correlation of Serum Erythropoietin Levels with Different Stages of Diabetic Retinopathy.

Abstract: OBJECTIVE To determine the correlation of serum erythropoietin concentration with diabetic retinopathy in patients with type 2 diabetes mellitus. STUDY DESIGN Cross-sectional study. Place and Duration of the Study: Department of Chemical Pathology and Endocrinology, Armed Forces Institute of Pathology (AFIP), Rawalpindi, from July to December 2021. METHODOLOGY A total of 180 individuals were enrolled in the study and placed in 2 groups as group 1 have 90 cases of type 2 diabetes mellitus and group 2 having 90 age-matched healthy controls. Group 1 was further subclassified into proliferative diabetic retinopathy (PDR) and non-proliferative diabetic retinopathy (NPDR) subgroups by an expert ophthalmologist. Serum erythropoietin, creatinine, blood HbA1c, and haemoglobin were analysed. Correlation between stages of proliferation and serum erythropoietin, creatinine, blood HbA1c, and haemoglobin were analysed. An independent-sample student t-test was applied to compare mean Serum erythropoietin between PDR and NPDR groups. Pearson's correlation was applied among disease severity, and type of retinopathy. A p-value of ≤0.05 was considered significant. RESULTS The average age of participants in groups 1 and 2 was 45.88±8.6 and 56.6±10.23 years, respectively. More males (n=60, 66.7%) were noted in cases compared to controls (n=42, 46.7%). serum erythropoietin concentration observed in cases (8.4±1.87 IU/L) was higher than controls (6.50±0.9). The mean serum erythropoietin concentration in PDR (9.35±1.74 IU/L) was significantly greater than that in NPDR (7.3±1.38 IU/L, p <0.001). The serum concentration of erythropoietin in group 1 increased linearly with the severity of the disease (r=0.103). CONCLUSION Serum erythropoietin concentrations increased in uncontrolled type 2 diabetics more so in proliferative retinopathy cases, and increased with disease severity. KEY WORDS Erythropoietin, Diabetic retinopathy, Proliferative diabetic retinopathy.

Clinical Utility of N-Terminal Prohormone B-Type Natriuretic Peptide Levels in Patients of Type 2 Diabetes Mellitus with Heart Failure

Abstract: Objective: To evaluate the effect of type 2 diabetes mellitus on plasma N-terminal prohormone B-type natriuretic peptide levels in patients with heart failure and correlate it with glycosylated haemoglobin levels. Study Design: Comparative cross-sectional study. Place and Duration of Study: Department of Chemical Pathology in collaboration with the Department of Cardiology,Combined Military Hospital, Multan Pakistan, from Feb to Sep 2021. Methodology: We assayed plasma NT-pro BNP levels in 194 individuals with established heart failure, (98 non-diabetics, and 96 patients with diabetes). Plasma NT-pro BNP levels were compared between groups in addition, the correlation of glycosylated haemoglobin with plasma NT-pro BNP levels was explored. Results: The mean plasma NT-pro BNP values were higher in patients with diabetes (15826.08 ±8143.434pg/mL) than in nondiabetics (12534.06±6323.92pg/mL) with a p-value 0.02. When NT-pro BNP was compared there was no significant found difference between the non-diabetic group and the Controlled Diabetes-Group (p-value 0 .882), but it was significantly higher in the Uncontrolled Diabetes-Group (p-value<0.001). A moderate positive association was found between NT-pro BNP and glycosylated haemoglobin (r=0.541, p-value<0.001). Conclusion: Although obesity has an inverse relation with plasma natriuretic peptides level and most patients with diabetes are overweight, the plasma NT-pro BNP is still a very informative tool and holds its significance as a diagnostic and prognosis marker in diabetic patients with heart failure.

Structural, dielectric, and magnetic properties of nickel rich manganese substituted Li2Ni6MnxCo2-xO10 nanomaterial synthesized via sol-gel method

Abstract: Manganese-substituted nickel-rich lithium-cobalt oxide Li2Ni6MnxCo2-xO10 was synthesized via the sol-gel auto-combustion method. The structure and morphology were investigated respectively by X-ray diffraction technique (XRD) and scanning electron microscopy (SEM) technique. Hexagonal structure was confirmed by XRD pattern with secondary phase. The crystallite size of the prepared nanomaterial was determined by modified Scherer modified (MSM), size-strain plot (SSP), and Williamson-Hall (W–H) method approaches. The average crystallite size has been correlated for each method and found to range from 12 to 27 nm. SEM was performed to investigate the surface morphology, particle size, and their distribution. The dielectric characteristics have been investigated with the effect of applied frequency in the range of 1 MHz–3 GHz. Synthesized material's dielectric characteristics such as impedance, electrical conductivity, modulus, and dielectric constant have been studied and found frequency dependent. Sensitivity response at high frequency suggested that the material is applicable for high-frequency devices. Magnetic measurements were made using M − H loops of coercivity (Hc), saturation magnetization (Ms), and retentivity (Mr). Both saturation magnetization and coercivity varied with increasing Mn concentration. The maximum value of Ms found at x = 0.50 and subsequently decreases with increasing Mn-content. Prepared samples are soft magnetic materials due to low coercive field. Further, the obtained dielectric properties suggested that the prepared materials can be used for energy storage applications.