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  1. Naz S, Uroos M, Ayoub M
    ACS Omega, 2021 Nov 02;6(43):29233-29242.
    PMID: 34746611 DOI: 10.1021/acsomega.1c04881
    This work presents a cost-effective approach for processing of renewable carbon-rich biomass using pyridinium-based Lewis acidic ionic liquids (LAILs). Rice husk as carbon-rich lignocellulosic waste was pretreated with a series of neutral and Lewis acidic ionic liquids to yield valuable intermediate platform monosaccharides. Novelty in the work lies in direct conversion of lignocellulosic carbohydrates into reducing sugars without their further conversion into 5-hydroxymethylfurfural or any other platform chemicals that are fermentation inhibitors for bioethanol production. The unconverted cellulose-rich material (CRM) is regenerated as a delignified material by the simultaneous addition of antisolvents. CRM and recovered lignin obtained after pretreatment were analyzed via scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy. The process was optimized with respect to a high yield of platform sugars and the quantity as well as quality of recovered CRM and lignin contents. Various reaction parameters involving the molecular structure of ionic liquids (ILs), Lewis acidic strength of ILs, biomass loading into IL, time, temperature, and biomass particle size were screened thoroughly. From all of the tested ILs, unsymmetrical 3-methylpyridinium IL having N-octyl substitution and chloroaluminate anion showed a greater conversion efficiency at 100 °C for 1.5 h. FTIR and SEM analyses of recovered CRM justify >90% lignin removal from rice husk. From all of the removed lignin, 60 wt % of original lignin content was recovered. The Lewis acidic system possessed recycling ability up to 3 times for subsequent treatment of rice husk without a significant loss of efficiency.
  2. Ayoub M, Khayoon MS, Abdullah AZ
    Bioresour Technol, 2012 May;112:308-12.
    PMID: 22437049 DOI: 10.1016/j.biortech.2012.02.103
    The synthesis of oxygenated fuel additives via solvent freebase-catalyzed etherification of glycerol is reported. The products of glycerol etherification arediglycerol (DG) and triglycerol (TG) with DG being the favorable one. The catalytic activity of different homogeneous alkali catalysts (LiOH, NaOH, KOH and Na(2)CO(3)) was investigated during the glycerol etherification process. LiOH exhibited an excellent catalytic activity during this reaction, indicated by the complete glycerol conversion with a corresponding selectivity of 33% toward DG. The best reaction conditions were a reaction temperature of 240°C, a catalyst/glycerol mass ratio of 0.02 and a reaction time of 6h. The influences of various reaction variables such as nature of the catalyst, catalyst loading, reaction time and reaction temperature on glycerol etherification were elucidated. Industrially, the findings attained in this study might contribute towards promoting the biodiesel industry through utilization of its by-products.
  3. Hussain A, Farrukh S, Hussain A, Ayoub M
    Environ Technol, 2019 Mar;40(7):843-854.
    PMID: 29161995 DOI: 10.1080/09593330.2017.1408696
    Most of the polymers and their blends, utilized in carbon capture membranes, are costly, but cellulose acetate (CA) being inexpensive is a lucrative choice. In this research, pure and mixed matrix membranes (MMMs) have been fabricated to capture carbon from natural gas. Polyethylene glycol (PEG) has been utilized in the fabrication of membranes to modify the chain flexibility of polymers. Multi-walled carbon nanotubes (MWCNTs) provide mechanical strength, thermal stability, an extra free path for CO2 molecules and augment CO2/CH4 selectivity. Membranes of pure CA, CA/PEG blend of different PEG concentrations (5%, 10%, 15%) and CA/PEG/MWCNTs blend of 10% PEG with different MWCNTs concentrations (5%, 10%, 15%) were prepared in acetone using solution casting techniques. Fabricated membranes were characterized using SEM, TGA and tensile testing. Permeation results revealed remarkable improvement in CO2/CH4 selectivity. In single gas experiments, CO2/CH4 selectivity is enhanced 8 times for pure membranes containing 10% PEG and 14 times for MMMs containing 10% MWCNTs. In mix gas experiments, the CO2/CH4 selectivity is increased 13 times for 10% PEG and 18 times for MMMs with 10% MWCNTs. Fabricated MMMs have a tensile strength of 13 MPa and are more thermally stable than CA membranes.
  4. Jahan R, Putra ZA, Ayoub M, Abdullah B
    ACS Omega, 2022 Nov 29;7(47):42700-42710.
    PMID: 36467939 DOI: 10.1021/acsomega.2c03066
    Ionic liquids (ILs) are efficient media for the liquid-phase sulfuric acid reaction. Under mild situations, the reaction of H2S with CH4 in ILs happens extremely quick and virtually complete, resulting in liquid sulfuric acid (H2SO4(l)). 1-hexyl-3-methylimidazolium chloride ([hmim][Cl]) ILs were formerly the most effective at capturing and converting H2S. It can convert H2S to H2SO4(l) with a proportion of up to 96%. This study aimed to develop cutting-edge techniques and assess their applicability for different acidic gas capacities and H2S amounts by considering three sustainability metrics which are people (safety), planet (ecological), and profit. Then, to maximize profit while lowering the global warming potential (GWP), fire explosion damage index (FEDI), and toxicity damage index (TDI), a multiobjective optimization (MOO) case was performed. The trade-off between economic, environmental, and safety performance was expressed through Pareto-optimal solutions. The improved wet sulfuric acid (WSA)-based IL method was safer (lower fire and explosion damage index), ecologically friendly (lower GWP), and portable. The findings indicate that the improved WSA-based on IL gives the optimum results compared to conventional WSA processes, such as the profit of 5688$/h increased from 1896$/h, the GWP of 0.0138-ton CO2-eq decreased from 0.0275-ton CO2-eq, the TDI of 6.72 decreased from 13.44, and the FEDI of 6.18 decreased from 20.6, respectively. This discovery opens the door to a viable strategy for capturing and converting H2S from an acid gas stream.
  5. Ahmad M, Zafar M, Sultana S, Ahmad M, Abbas Q, Ayoub M, et al.
    Microsc Res Tech, 2018 Sep;81(9):1004-1016.
    PMID: 30303585 DOI: 10.1002/jemt.23066
    Pollen micro-morphological features have proven to be helpful for the plant taxonomists in the identification and classification of plants. The utilization of this plantmayhelpfulin the areas of lignocellulosic conversion to biofuels and diversify application toward biomass. The current study was planned with the aim to evaluate the pollen features of complex Ranunculaceous flora of District Chitral, Northern Pakistan using both scanning electron microscopy (SEM) and Light Microscope (LM) for their taxonomic importance. Pollens of 18 Ranunculaceous species belonging to 6 genera were collected from different localities of the research area. SEM and LM were used to examine both qualitative and quantitative micro-morphological features. Sculptring of the sexine include; Scabrate, psilate, echinate, verrucate, perforate gemmate, and reticulate and so forth. Shape of the pollens was sub-spheroidal, spheroidal, prolate, subprolate and oblate and so forth. Type of pollen was ranged from mono to tricolpate and tricolporate. Quantitative characters include length/width of the pollen, colpus, exine thickness, and P/E ratio. Based on these micro-morphological features a taxonomic key was prepared for the fast and correct identification. RESEARCH HIGHLIGHT: Study of the pollen micro-morphological features of Ranunculaceous species by SEM and LM. Analysing both qualitative and quantitative characters of the pollens. Preparation of taxonomic key based on micro-morphological features for the correct and fast identification.
  6. Danish M, Kale P, Ahmad T, Ayoub M, Geremew B, Adeloju S
    Data Brief, 2020 Apr;29:105225.
    PMID: 32154335 DOI: 10.1016/j.dib.2020.105225
    The dataset presented here are part of the data planned to produce biodiesel from flaxseed. Biodiesel production from flaxseed oil through transesterification process using KOH as catalyst, and the operating parameters were optimized with the help of face-centered central composite design (FCCD) of response surface methodology (RSM). The operating independent variables selected such as, methanol oil ratio (4:1 to 6:1), catalyst (KOH) weight (0.40-1.0%), temperature (35 °C-65 °C), and reaction time (30 min-60 min) were optimized against biodiesel yield as response. The maximum yield (98.6%) of biodiesel from flaxseed can achieved at optimum methanol oil ratio (5.9:1), catalyst (KOH) weight (0.51%), reaction temperature (59.2 °C), and reaction time (33 min). The statistical significance of the data set was tested through the analysis of variance (ANOVA). These data were the part of the results reported in "Optimization of process variables for biodiesel production by transesterification of flaxseed oil and produced biodiesel characterizations" Renewable Energy [1].
  7. Qasim M, Ayoub M, Aqsha A, Ghazali NA, Ullah S, Ando Y, et al.
    ACS Omega, 2022 Nov 15;7(45):40789-40798.
    PMID: 36406530 DOI: 10.1021/acsomega.2c02993
    CO2 levels in the atmosphere are growing as a result of the burning of fossil fuels to meet energy demands. The introduction of chemical looping combustion (CLC) as an alternative to traditional combustion by transporting oxygen emphasizes the need to develop greener and more economical energy systems. Metal oxide, also defined as an oxygen carrier (OC), transports oxygen from the air to the fuel. Several attempts are being made to develop an OC with a reasonable material cost for superior fuel conversion and high oxygen transport capacity (OTC). This study aims to synthesize a potential OC using the wet impregnation method for the CLC process. Thermogravimetric analysis (TGA) was used to determine the cyclic redox properties using 5% CH4/N2 and air as reducing and oxidizing gases, respectively. The 10CuPA-based OC retained a high OTC of about 0.0267 mg O2/mg of OC for 10 cycles that was higher than 10CuA-based OC. Furthermore, the oxygen transfer rate for 10CuPA-based OC was relatively higher compared to 10CuA-based OC over 10 cycles. In comparison to 10CuA-based OC, the 10CuPA-based OC presented a steady X-ray diffraction (XRD) pattern after 10 redox cycles, implying that the phase was stably restored due to praseodymium-modified γ alumina support.
  8. Inayat A, Rocha-Meneses L, Ayoub M, Ullah S, Abdullah AZ, Naqvi SR, et al.
    Environ Sci Pollut Res Int, 2023 Jun;30(28):72224-72235.
    PMID: 37170050 DOI: 10.1007/s11356-023-27371-w
    This study investigated the effect of different Co3O4-based catalysts on the catalytic decomposition of nitrous oxide (N2O) and on nitric oxide (NO) conversion. The experiments were carried out using various reaction temperatures, alkaline solutions, pH, mixing conditions, aging times, space velocities, impregnation loads, and compounds. The results showed that Co3O4 catalysts prepared by precipitation methods have the highest catalytic activity and N2O conversion, even at low reaction temperatures, while the commercial nano and powder forms of Co3O4 (CS) have the lowest performance. The catalysts become inactive at temperatures below 400 °C, and their activity is strongly influenced by the mixing temperature. Samples without stirring during the aging process have higher catalytic activity than those with stirring, even at low reaction temperatures (200-300 °C). The catalytic activity of Co3O4 PM1 decreases with low W/F values and low reaction temperatures. Additionally, the catalyst's performance tends to increase with the reduction process. The study suggests that cobalt-oxide-based catalysts are effective in N2O catalytic decomposition and NO conversion. The findings may be useful in the design and optimization of catalytic systems for N2O and NO control. The results obtained provide important insights into the development of highly efficient, low-cost, and sustainable catalysts for environmental protection.
  9. Ghumman ASM, Shamsuddin R, Qomariyah L, Lim JW, Sami A, Ayoub M
    PMID: 38622423 DOI: 10.1007/s11356-024-33317-7
    Metal-organic frameworks (MOFs) have emerged as highly promising adsorbents for removing heavy metals from wastewater due to their tunable structures, high surface areas, and exceptional adsorption capacities. This review meticulously examines and summarizes recent advancements in producing and utilizing MOF-based adsorbents for sequestering heavy metal ions from water. It begins by outlining and contrasting commonly employed methods for synthesizing MOFs, such as solvothermal, microwave, electrochemical, ultrasonic, and mechanochemical. Rather than delving into the specifics of adsorption process parameters, the focus shifts to analyzing the adsorption capabilities and underlying mechanisms against critical metal(loid) ions like chromium, arsenic, lead, cadmium, and mercury under various environmental conditions. Additionally, this article discusses strategies to optimize MOF performance, scale-up production, and address environmental implications. The comprehensive review aims to enhance the understanding of MOF-based adsorption for heavy metal remediation and stimulate further research in this critical field. In brief, this review article presents a comprehensive overview of the contemporary information on MOFs as an effective adsorbent and the challenges being faced by these adsorbents for heavy metal mitigation (including stability, cost, environmental issues, and optimization), targeting to develop a vital reference for future MOF research.
  10. Cheng YW, Chong CC, Lam MK, Ayoub M, Cheng CK, Lim JW, et al.
    J Hazard Mater, 2021 05 05;409:124964.
    PMID: 33418292 DOI: 10.1016/j.jhazmat.2020.124964
    Thriving oil palm agroindustry comes at a price of voluminous waste generation, with palm oil mill effluent (POME) as the most cumbersome waste due to its liquid state, high strength, and great discharge volume. In view of incompetent conventional ponding treatment, a voluminous number of publications on non-conventional POME treatments is filed in the Scopus database, mainly working on alternative or polishing POME treatments. In dearth of such comprehensive review, all the non-conventional POME treatments are rigorously reviewed in a conceptual and comparative manner. Herein, non-conventional POME treatments are sorted into the five major routes, viz. biological (bioconversions - aerobic/anaerobic biodegradation), physical (flotation & membrane filtration), chemical (Fenton oxidation), physicochemical (photooxidation, steam reforming, coagulation-flocculation, adsorption, & ultrasonication), and bioelectrochemical (microbial fuel cell) pathways. For aforementioned treatments, the constraints, pros, and cons are qualitatively and quantitatively (with compiled performance data) detailed to indicate their process maturity. Authors recommended (i) bioconversions, adsorption, and steam reforming as primary treatments, (ii) flotation and ultrasonication as pretreatments, (iii) Fenton oxidation, photooxidation, and membrane filtration as polishing treatments, and (iv) microbial fuel cell and coagulation-flocculation as pretreatment or polishing treatment. Life cycle assessments are required to evaluate the environmental, economic, and energy aspects of each process.
  11. Zulqarnain, Mohd Yusoff MH, Ayoub M, Ramzan N, Nazir MH, Zahid I, et al.
    ACS Omega, 2021 Jul 27;6(29):19099-19114.
    PMID: 34337248 DOI: 10.1021/acsomega.1c02402
    The energy demand of the world is skyrocketing due to the exponential economic growth and population expansion. To meet the energy requirement, the use of fossil fuels is not a good decision, causing environmental pollution such as CO2 emissions. Therefore, the use of renewable energy sources like biofuels can meet the energy crisis especially for countries facing oil shortages such as Pakistan. This review describes the comparative study of biodiesel synthesis for various edible oils, non-edible oils, and wastes such as waste plastic oil, biomass pyrolysis oil, and tyre pyrolysis oil in terms of their oil content and extraction, cetane number, and energy content. The present study also described the importance of biodiesel synthesis via catalytic transesterification and its implementation in Pakistan. Pakistan is importing an extensive quantity of cooking oil that is used in the food processing industries, and as a result, a huge quantity of waste cooking oil (WCO) is generated. The potential waste oils for biodiesel synthesis are chicken fat, dairy scum, WCO, and tallow oil that can be used as potential substrates of biodiesel. The implementation of a biodiesel program as a replacement of conventional diesel will help to minimize the oil imports and uplift the country's economy. Biodiesel production via homogeneous and heterogeneous catalyzed transesterification is more feasible among all transesterification processes due to a lesser energy requirement and low cost. Therefore, biodiesel synthesis and implementation could minimize the imports of diesel by significantly contributing to the overall Gross Domestic Product (GDP). Although, waste oil can meet the energy needs, more available cultivation land should be used for substrate cultivation. In addition, research is still needed to explore innovative solvents and catalysts so that overall biodiesel production cost can be minimized. This would result in successful biodiesel implementation in Pakistan.
  12. Karim SS, Murtaza Z, Farrukh S, Umer MA, Ali SS, Younas M, et al.
    Environ Res, 2022 Apr 01;205:112402.
    PMID: 34838569 DOI: 10.1016/j.envres.2021.112402
    The emerging growth of the electronic devices applications has arisen the serious problems of electromagnetic (EM) wave pollution which resulting in equipment malfunction. Therefore, polymer-based composites have been considered good candidates for better EMI shielding due to their significant characteristics including, higher flexibility, ultrathin, lightweight, superior conductivity, easy fabrication processing, environmentally friendly, corrosion resistive, better adhesion with physical, chemical and thermal stability. This review article focused on the concept of the EMI shielding mechanism and challenges with the fabrication of polymer-based composites. Subsequently, recent advancements in the polymer composites applications have been critically reviewed. In addition, the impact of polymers and polymer nanocomposites with different fillers such as organic, inorganic, 2D, 3D, mixture and hybrid nano-fillers on EMI shielding effectiveness has been explored. Lastly, future research directions have been proposed to overcome the limitations of current technologies for further advancement in EMI shielding materials for industrial applications. Based on reported literature, it has been found that the low thickness based lightweight polymer is considered as a best material for excellent material for next-generation electronic devices. Optimization of polymer composites during the fabrication is required for better EMI shielding. New nano-fillers such as functionalization and composite polymers are best to enhance the EMI shielding and conductive properties.
  13. AlSahow A, AlQallaf A, AlYousef A, Bahbahani H, Bahbahani Y, AlHelal B, et al.
    Int Urol Nephrol, 2023 Mar;55(3):721-727.
    PMID: 36136260 DOI: 10.1007/s11255-022-03368-1
    INTRODUCTION: Hemodialysis (HD) patients are at increased risk of severe COVID-19 infection but infection rates vary. Our objectives are to describe COVID-19 positive HD patients' characteristics, infection rates, and factors associated with mortality in HD COVID-19 cases in Kuwait.

    METHODS: Data on demographics, comorbidities, and treatments received, as well as mortality for HD patients admitted to hospitals for COVID-19, from 1/March to 31/July 2020, prospectively collected and analyzed.

    RESULTS: A total of 141 infected HD patients were admitted (Mean age 58 ± 16.1; Males 56%), representing 7% of the total HD population and 0.2% of all COVID-19 cases during the study period. Of those 141 infected HD patients, 27 (19%) died, and this represents 6% of total COVID-19-related mortality and 27% of the total HD mortality. In contrast, total covid-19-related mortality of all positive cases was only 0.7%, and total HD mortality during the study period was only 5%. COVID-19-positive HD patients who died were older and 59% were males. However, the differences were not statistically significant. Of the 61 infected HD patients who needed to be switched to continuous kidney replacement therapy (CKRT), 34% died, and of the 29 infected HD patients who needed admission to intensive care, 65% died.

    CONCLUSION: HD population represents a small fraction of the total population; however, positive HD COVID-19 cases represent a sizable proportion of COVID-19 cases and a significant percentage of total COVID-19-related mortality, and total HD mortality.

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