Department of Chemistry

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Substitution of Alkali Metal Atoms: An Efficient Approach to Enhance Electronic and Nonlinear Optical Properties of Diamantane
(library Information Services CUI Lahore Campus, 2020-02-16) Palwasha Khan; SP19-R06-012; Dr. Mazhar Amjad Gilani; LHR TP 6515
Applications of nonlinear (NLO) materials in the fields like electronics, optics, optoelectronics, and optical computing, etc. drive the interest of many scientists to design high-performance NLO materials. Electronic properties, absorption spectra and nonlinear optical properties of alkali metal substituted diamantanes are presented. A significant reduction in HOMO-LUMO gap has been observed by alkali metal substitution. K@CHa has the lowest H-L gap of 1.64 eV as compared to 8.88 eV for pristine diamantane. A remarkable increase in the first hyperpolarizability (βₒ) has been observed due to the substitution of alkali metals. Among these structures, K substituted complexes show the largest first hyperpolarizability (25526-36328 a.u). This significant increase in the first hyperpolarizability (βₒ) is attributed to low crucial transition energies ΔE. K@CHa has the lowest ΔE value (2.0650 eV) which results in the highest βₒ value (36328 a.u.) for K@CHa. Furthermore, frequency-dependent hyperpolarizabilities calculations are carried out using 1906 nm, 1340 nm, and 1064 nm frequencies for commonly used lasers. This study provides an efficient approach to design high-performance NLO materials having extensive applications in the field of electronics and optoelectronics. The results reveal that substitution of alkali metals leads to the shift in absorption from ultraviolet to the visible
Bi-doping of Alkali Metals M2 (M2=Li2, Na2, and K2) on Al12N12 Nano-cage: A New Effective Approach to Design Nonlinear Optical Material
(library Information Services CUI Lahore Campus, 2020-02-16) Muhammad Sohail; FA18-R06-025; Dr. Mazhar Amjad Gilani; LHR TP 5966
Under the framework of density functional theory (DFT), M2@x-Al12N12 (M2=Li2, Na2, and K2; x=b66, Ntop, and r6) complexes have been designed. These highly stable complexes are formed through doping of bi-alkali metals at the surface of inorganic Al12N12 nano-cage. Both alkali metal atoms were doped in a trans-fashion over nitrogen atoms of Al12N12 (Ntop) or Al-N fused bond (b66) and over six-membered rings (r6). For the b66 and Ntop positions, the trend of stability for the complexes is Li2->Na2->K2-complexes. However, in cage doping position of r6, the stability is increased in the order of Li2->K2->Na2-complexes. The analysis of our computed data revealed that the large band-gap between HOMO (Highest occupied molecular orbital) and LUMO (Lowest unoccupied molecular orbital) of pure Al12N12 nano-cage can be decreased significantly within the range of 0.74-1.67 eV through doping of bi-alkali metals, thus showing the fascinating n-type behavior. A new HOMO orbital formed between the original band-gap of pure Al12N12 is responsible for the reduction in band gap. The doping of bi-alkali metals M2 on Al12N12 nano-cage results in a remarkable nonlinear optical response (β0). The calculated highest first hyperpolarizability values are 127397.94 au for K2@Ntop-Al12N12, 670.67 au for K2@r6-Al12N12, and 1028 au for Na2@b66-Al12N12 respectively. The hyperpolarizability values are increased with the increase in the atomic number of bi-alkali metals when bi-alkali metals are doped over Ntop and r6 positions. These intriguing results would be helpful to pursue future uses of modified doped Al12N12-based nano-cages in the latest kind of electronic and high efficient NLO (Nonlinear optical) nano-devices.
Synthesis and Characterization of Carbon & Nitrogen based Covalent Organic Framework to Explore Biomedical Application
(library Information Services CUI Lahore Campus, 2020-02-16) Bakar bin Khatab Abbasi; FA18-R06-031; LHR TP 5969; Dr. M. Shahid Nazir
Covalent organic frameworks (COFs) represent a class of advanced porous materials with outstanding properties such as less density, excellent surface area, and adjustable pore structure and size. These materials proved themselves promising in several fields including separation science, catalysis, sensing, and biomedicine. Recently, many techniques have been developed to synthesize different types of COFs for instance boron-based COFs, imine-based COF, hydrazine-based COFs, and ketoenamine-based COFs according to the nature of linkers and the purpose of application. Among these types of COFs, imine-based COFs are found to be most potential candidate for various applications. Major selection factors in the synthesis of COFs include stability of monomers and facile synthesis route at room temperature. Keeping in view all the above aspects, an imine-based COF has been synthesized at room temperature. Triformylbenzene (TFB) and benzidine (BD) monomers reacted at reported conditions and successfully obtained COF, donated as TFB-BD. Successful synthesis and structure of the COF TFB-BD was confirmed by FTIR and XRD. In FTIR the C=N peak at 1617 cm-1 clearly indicated the formation of framework between the two monomers. In XRD strongest diffraction peak at 2Ө at 2.66° presented confirmation of crystalline nature of synthesized COF-TFB-BD. Furthermore, in SEM and TEM imaging, the morphological characteristic showed porous nature of the prepared COF. Literature describes the utilization of this COF may be explored for biomedical application.
Synthesis and Characterization of Dipyromethanes and Their Metal Complexes for Glucose Detection
(library Information Services CUI Lahore Campus, 2020-02-16) Adeel Ahmed; FA18-R06-013; Dr. Sara Riaz; LHR TP 5964
Glucose plays an active part in human body such as balancing the body in non-fortified feature, generating energy and improve memory enlargement. Blood glucose concentration is a universal benchmark of a patient’s fitness, particularly for threatening mark related with diabetes mellitus. Due to increased numeral of diabetic patients, various methodologies for glucose determination have been employed to assist precise and uninterrupted glucose detection. In present work, an advanced enzyme free electrochemical device has been proposed for glucose measurements. We intended to synthesize various derivatives of Dipyromethanes (DPM) via microwave assisted synthesis for the detection of Glucose. The synthesis of DPM is generally acid catalyzed reactions that occur in the existence of organic solvent dichloromethane (CH2Cl2). However, the problem of refinement and separation associated with conventional synthetic routs limits their synthesis and utilization in numerous fields. To avoid the lengthy and time consuming process of crystallization and separation we aim to further synthesize their transition metal complexes with Zn. The complexes of DPMs were purified via simple centrifugation. These DPM complexes were further drop casted onto carbon based electrodes (preferably glassy carbon electrodes) to study their electrochemical properties. For this purpose, the electrochemical biosensor was prepared by the modification of a freshly glassy carbon electrode surface with zinc-dipyromethanes complex. The spectral studies were done by UV-visible spectrophotometer and fluorescence spectrophotometer. The surface morphology and structure of the prepared complex were analyzed by AFM, FTIR, and XRD. The electrochemical characteristics of the complex were evaluated by CV and EIS. The results of CV (oxidation peak at 0.33V) indicated that zinc-dipyromethanes complex (Zn-DPM) can efficiently oxidize the glucose without any enzymes assistance and can further be used for glucose detection.
Growth of ZnO NanoFlakes on Flexible Carbon Based Transducer Surface for Electrochemical Sensing of Acetone
(library Information Services CUI Lahore Campus, 2020-02-16) Seemal Mansoor; FA18-R06-026; LHR TP 5967; Dr. Sara Riaz
The present study was concentrated to develop a rapid, electrochemical, selective, cheap and easy to use carbon cloth (CC) based assay for the quantitative and qualitative detection. CC was fabricated with a ZnO nanoparticles first and then with diazonium salt. This modified CC was then applied for the detection of acetone. FTIR, AFM and SEM was used to explore the chemical and physical characteristics of CC of before and after each modification. These results manifested that ZnO-nanoflakes and diazonium salt functionalization could increase the roughness of the CC surface that was advantageous to promote the interaction between CC and analyte to be detected. Linear sweep voltammetry and cyclic voltamogram were used for electrochemical analysis. The proposed electrochemical sensor was analyzed for various concentration of acetone. To validate the concept, the proposed sensor was assessed for higher concentrations of acetone in different ways. Among them, ZnO nanoflakes/ CC which was modified with diazonium salt showed better response (in acetone solution alone) than ZnO nanoflakes /modified CC (in the solution of diazonium salt and variable concentrations of acetone)
Fabrication of Electro-active Nano-trans Surfaces to Design Label Free Aptasensor for Ochratoxin-A Detection
(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-17) MAHAM LIAQAT; FA18-R06-004; Dr. Akhtar Hayat; LHR TP 5961
With increased awareness of nutrition and the advocacy for healthier food choices, there exists a great demand for a simple, low-cost, label free and easy-to-use assays that can reliably detect toxins in agriculture products. In this regard, a simple and highly sensitive electrochemical sensing platform based on the structural switching signaling of aptamer has been developed for the detection of smaller molecules using Ochratoxin A as a model analyte. Pencil electrode was first modified with highly conductive Graphene oxide/Fe3O4NP/PPY composite and then was self-assembled with aptamer using EDC/NHS technique. This immobilized nanoprobe provided gates of tunnels for the effective electron flow showing higher peak current. The introduction of the target analyte (OTA) triggered switching of the aptameric structure resulting in the decrement of the redox current. This decrease was proportional to the analyte concentration, thus featuring signal on/off strategy. This proposed transducing design showed a dynamic linear range (10 pg/mL-200ng/mL) with Limit of detection and limit of quantification of 5pg/mL and 40pg/mL respectively. We demonstrate this transducing design as a general inexpensive and reproducible method to specifically detect a wide variety of analytes by selecting a suitable biorecognation element. Real sample analysis was performed for the real time approach and results collected are in agreement with practical application.
Non-Enzymatic Electrochemical Sensing of Dopamine based on Transition Metal Oxides/CNTs
(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-17) Shamim Ramzan; FA18-R06-009; Dr. Abdur Rahim; LHR TP 5963
Sensing with the aid of metal oxides and CNTs is the most vibrant field of electrochemical science, which endows an ambit for various innovative and novel functions with a variety of applications. Enzymatic sensors are costly, lack of stability, have difficult immobilization techniques as well as electrodes used for electrochemical analysis of neurotransmitter concentrations are also unable to monitor the potential of these species. Besides, sensors with the most robust and reliable electrodes generally tend to deteriorate over months of use. Therefore, a study has been designed to synthesize CNTs based metal oxides nanoparticles by green synthesis method using the lignin as a modifier and reducing agent. The synthesize materials have been characterized by different techniques, i.e. SEM, XRD, and FTIR for surface morphology, determination of nanostructure, and functionalization of surface. The synthesized materials such as C2O3@CNTs/lignin, and CuO@CNTs/lignin have been used for the surface modification of glassy carbon electrode (GCE). These composites are supposed to be used as a promising material for dopamine sensing by giving excellent electrochemical properties.
Thermal Stability and Fire Retardant Studies of Polymeric Nanocomposites based on Layered Double Hydroxides
(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-17) Raheel Ayub; FA18-R06-006; Dr. M. Shahid Nazir; LHR TP 5959
Layered double hydroxide (LDH) has been used as nanofiller in different polymer industry and gained extra intention in 21th century due to substantially improved physical, electrical, mechanical and extraordinary flame retardant properties. LDH nanofiller have variable charge density, which allows various interactions with the host polymer matrices. In this study, MOF based LDH and MOF based CNTs/LDH nanocomposites were synthesized by using MOF and CNTs as precursor respectively, by co-precipitation method to improve flame retardant efficiency of polymer. Pristine LDH have limitations of toxicity, low limited oxygen index (LOI %), high peak heat release rate, and high loadings. Acidic modification of MWCNTs was synthesized by co-precipitation method with nitric acid (HNO3) and sulphuric acid (H2SO4). MOF based LDH and MOF based CNTs/LDH were confirmed by FTIR described peaks at at 2,927 cm-1, 1528 and 1048 cm-1 attributed to the vibration of aliphatic sp3 C–H, C = O and C–O respectively along with the broad peaks around 3000-3400 cm-1 of water molecules of LDH. Hollow dodecahedral structure of MOF based LDH and MOF based CNTs/LDH nanocomposites were confirmed by Scanning Electron Microscopy (SEM) represented greater surface active sites and synergistic effect for polymer. Thermal property of MOF based LDH and MOF based CNTs/LDH nanocomposites were confirmed by Thermo Gravimetric Analysis (TGA) which described initial weight loss at 137ºC attributed to the removal of water between the layers and maximum weight loss at above 450ºC due to nitrates and hydroxyl ions, significantly higher than pristine LDH. This work advances progress on the development of highly safe multifunctional polymeric nanocomposites for economical use and reduced life threat.
Surface Etched Mixed Matrix Membrane for Desulfurization of Model Diesel Oil
(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-17) Sadaf Ahmad; FA18-R06-001; Dr. M. Shahid Nazir; LHR TP 5959
Fuel counts in basic necessity of modern life. However, fuel consumption has been turned into severe danger to the environment as well as human life due to the presence of sulfur components in fuel. Therefore, it has become essentially important to achieve ultra-low sulfur fuel. For this purpose, desulfurization has been vastly undergoing by using various techniques in recent decades. Polyoxometalates (POMs) are polyatomic anions comprising transition metal oxyanions associated with bridged oxygen atoms resulting in closed three-dimensional assemblies. POMs and their hybrid materials (such as POM-based porphyrin and POM based metal-organic frameworks (MOFs)), have been mostly reported in multidisciplinary research fields as brilliant candidates due to their characteristics properties. Specifically, hybrids of POM and porphyrin (~ POM@Porphyrin = POMOF) are outstanding materials for intended applications which being inorganic filler further incorporate in mixed matrix membranes (MMMs). MMMs generally fabricated through incorporation of inorganic fillers in polymeric matrix, have achieved great attention in recent research progress due to multiple applications in gas storage, catalysis, sensing, wastewater treatment, and biomedicine. The main objective of the current study is to use POMOF as a catalyst in desulfurization. Therefore, three POMOFs were fabricated by varying ratios (1:1, 2:1, 3:1) of cationic and anionic species. Characterization analyses such as UV/Vis, FTIR, and TGA showed successful synthesis of these POMOFs. The efficiency of POMOFs followed an order as 3 (95.5%)> 2 (85.5%)> 1 (70.3%). Among these three POMOFs, 3 exhibited excellent catalytic property in desulfurization. Furthermore, the desulfurization process could be recycled for ten times without a significant decrease in catalytic efficiency. Interestingly, POMOFs successfully accomplished desulfurization of model diesel oil and showed excellent renewability. To the best of our knowledge, such kind of POMOFs with special surroundings and bi-functional active sites are not reported.
Green Synthesis of Silver Nanocomposites from Powders of Various Medicinal Plants and Study of their Antimicrobial Potential
(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-17) Hira Ashfaq; FA18-R06-003; Dr. Lubna Sherin; LHR TP 5960
The application of plant waste materials in the synthesis of nanomaterials is an efficient and inexpensive method to minimize the practice of expensive chemicals. It is because of the reason that it gives rise to green approaches that abstain from the addition of toxic chemicals into the environment. The research work focuses on the synthesis of silver nanocomposites using powders of various therapeutically reported plants and the study of their potential regdaring chromium metal decontamination. For characterization, the techniques of X-ray Diffraction XRD and Fourier Transform Infrared Spectroscopy FT-IR has been used. Waste water treatment is performed for adsorptiove removal of chromium. Optimization is carried out using batch methods for various parameters like, pH, adsorbent dose and time of contact. Isothermal and kinetics study have shown that removal of chromium using silver nanocomposite was a feasible process, following langmuir adsorption model and pseudo second order reaction kinetics.
Synthesis and Characterization of Fluorescent Quantum Dots as Probes to Study Radiation Induced ds-DNA Damage
(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-17) Muhammad Hassan Ahmad; SP19-R06-007; Dr. Mian Hasnain Nawaz; LHR TP 6511
DNA is primarily a vital biomolecule that could be ambushed by both exogenous and endogenous sources of damage. Both exogenous and endogenous threats could provoke more than 105 DNA lesions spontaneously in human cells every day. The former sources come in a number of ways including, among others, ionizing radiations, ultraviolet (UV) light, thermal or hydrolysis disruption, environmental and industrial chemicals. Damages occurred by endogenous sources may come from several internal cellular processes like epigenetic modifications, hydrolysis, alkylation, nucleobase oxidation, adduct formations in bulk and errors in DNA replication by mismatch in nucleobases. Therefore, conservation of genome integrity is critical for traits inheritance to offspring and survival of any organism. Development of a rapid, sensitive and simple tool for the screening of DNA damage is the need of time. Fluorescence method is applied in a number of ways for the recognition of specific sequences of Deoxyribonucleic acid (DNA) along with Ribonucleic acid (RNA). QDS which are semiconductor nanoparticles, possess many unique structural and functional features such as nanoscale size, suitable fixity, narrow emission spectra, versatile surface modification and high specific surface area. Owing to these exceptional characteristics, these particles are used as markers, fluorescent probes and biosensors in numerous fields. The monolayered MoS2 owing small lateral size could offer novel optical properties due to their quantum confinement effect and it could act as a promising material for the development of novel optical sensors and optoelectronic devices. A highly fluorescent MoS2 QDs based FL emission sensor was formulated to study the radiation induced ds-DNA damage. The ds-DNA solution was exposed to UV radiation and ultra-sonic waves for definite period of time to induce the ds-DNA lesions. The FL emission spectra of MoS2 QDs with different concentrations of damaged ds-DNA was observed. A significant quenching in FL intensity of highly fluorescent MoS2 QDs indicated the presence of active sites in damaged ds-DNA which formed interactions with QDs and reduced the FL activity of fluorescent QDs. The excitation wavelength (260 nm) and concentration (200 μl) for QDs was optimized and used throughout the experiment process.
Density Functional Theory (DFT) Investigation of Electronic and Optical Properties of Azo Dyes
(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-17) Muhammad Fahid Asif; FA18-R06-027; Dr. Mazhar Amjad Gilani; LHR TP 5968
Nonlinear optics is an important field of research owing to its extensive usage in advanced technologies. NLO materials have widespread applications in photonics and optoelectronics. NLO materials are crucial components of optical fibers, optical computing, data processing devices, optical sensors, optical modulators, high density optical storage devices, and ultra-fast optical switches. Five commercially available azo dyes, Acid Orange 5, Acid Orange 61, Direct Red 111, Food Yellow 6 and Metanil Yellow were theoretically investigated for their electronic and nonlinear optical properties using density functional theory (DFT) calculations. Each azo dye exhibits one alkaline and two acidic forms dominantly. So, all the three forms of these azo dyes were considered for calculations. Computational results reveal that these dyes possess high planarity across Ar-N=N-Ar’ linkage. Dihedral angles of alkaline and acidic I forms are found in range of 179o-179.9o. In acidic II forms, dihedral angles are distorted up to 176o owing to their geometrical change due to protonation. FMO analysis shows reduced HOMO-LUMO band gap for acidic forms as compared to alkaline forms. The drop in Eg values is attributed to the protonation which stabilizes the molecule by countering the excessive negative charge due to the sulphonic group. The HOMO-LUMO band gap lies in the range of 2-5 eV. The lowest HOMO-LUMO band gap of 2.54 eV is observed for AO61 AC I form. Low Eg values make azo dyes conductors. Furthermore, the effect of protonation of the dyes on nonlinear optical (NLO) responses was thoroughly investigated. Long range corrected method CAM-B3LYP/6-311-g(d) was employed for computation of polarizability and hyperpolarizability values. The results show that protonation of the dyes brings significant increase in nonlinear response. The highest first hyperpolarizability is observed for DR111 AC II (βo =2.6 x 104 au). TD-DFT calculations were also carried out to find change in dipole moment, crucial excited state energy difference and oscillator strength to estimate first hyperpolarizability using two-level-model. The βo (TLM) values calculated for dyes using two-level-model are comparable to the βo. It was also found that the change in dipole moments and change in excitation energies are the decisive factors for the increased first hyperpolarizabilities. In order to find the practical usability of the dyes in the field of nonlinear optics, FD-DFT calculations were performed at 532nm and 1064nm. The values of β (-2ω, ω, ω) and β (-ω, ω, 0) are estimated of the orders of 106 au and 105 au, respectively. The results are found to be quite supportive for application of the studied azo dyes in SHG phenomena.
Fabrication of Nanostructured Receptors-based Device for the Detection of Dengue Fever
(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-17) ANUM TAHIR; SP19-R06-030; Dr. Usman Latif; LHR TP 6525
Dengue belongs to a family of Flaviviridae virus and is a single-stranded, positive, enveloped RNA virus having four serotypes: DENV-1, DENV-2, DENV-3, and DENV-4. DENV infection generates ten viral protein products that have nonstructural components (NS1, NS5, NS2A, NS4A, NS2B, NS4B and NS3) and structural components (envelope, capsid and pre-membrane). NS1 is an efficiently used biological marker for the diagnostic purpose of the early stages of dengue. This is because of its presence in all the serotypes of the dengue and its secretion before the production of antibodies against the virus. NS1 dengue viral protein is secreted and accumulated in extracellular space as a hexametric lipoprotein specie. Development of various methods has been reported against dengue’s nonstructural protein 1(NS1) such as detection of viral RNA through a reverse transcription-polymerase chain reaction, serological test, viral culture, enzyme-linked immunosorbent assay, etc. However, these conventional techniques lead to unacceptable time delays, cost, sensitivity, selectivity, and energy. To eliminate these pitfalls, researchers are intending to develop a proficient biosensor for diagnosing NS1 that possess high specificity, sensitivity, and simplicity. Therefore, it is imperative to develop a simple, sensitive, and selective diagnostic technique for the detection of dengue. Molecular imprinting sensors have been developed due to their good sensitivity and specific molecular recognition ability. This facile, robust, and nonbiological approach has been used to detect large molecules such as protein. The main drawback of using proteins as templates is their complex and flexible three-dimensional structure which unfolds easily with minimal changes in the environment. In addition, it is difficult to elute template molecules embedded in molecularly imprinted polymers. Therefore, stable and rigid 3D proteins are strongly preferred for imprinting purposes. The most promising strategy to overcome the complications is to decrease the complexity of the template to achieve successful protein imprinting. Hence, an elegant approach for a new, inexpensive protein imprinting method has been reported in recent years under the x name of epitope imprinting. This imprinting technique involves the use of a small fragment of target protein (epitope) as a template resulting in the formation of MIP layer which will be able to identify the whole protein molecule.
Photocatalytic Degradation of Organic Wastewater Pollutants by Green Photocatalyst
(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-17) Rizwan Akbar; FA18-R06-016; Dr. Lubna Sherin; LHR TP 5965
Dyes present in industrial wastewater are harmful to humans as well as environment. They are non-biodegradable synthetic materials that are difficult to degrade naturally. At present the simplest, economical and ecofriendly method for dye degradation is application of metal oxides nanoparticles as photocatalyst. Fabrication of metal oxide nanoparticles by using safe and cheap natural products as reducing and capping agents is highly interesting field in material sciences. This research focuses on green synthesis of copper oxide nanoparticles (CuO NPS) by using propyl gallate as reducing, capping and stabilizing agent. It was confirmed and characterized by UV-visible spectroscopy, XRD crystallography and FTIR analysis. Synthesized nanoparticles was employed as photocatalyst for the degradation of various waste- water dyes and optimization of dye degradation was carried out for various parameters like, pH, temperature, and dye concentration. The results demonstrate that in comparison to methyl orange it was more efficient against methylene blue and congo red degradation with 93 % and 89% removal respectively in 120 minutes.
Amine Functionalized Mesoporous Silica and Polyurethane Based Membrane for Cationic Natured Dye Removal from Industrial Waste Water
(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-19) Muhammad Hassan Sajjad; SP19/R06-014; Dr. Nawshad Muhammad; LHR TP 6517
Textile, leather, printing, paper, plastic and other industries have been producing large amount of waste water containing harmful dyes now a days. Most dyes that are stable to ultraviolet light are not decomposable in the textile industry. They are also immune to aerobic digestion which makes them a long-term water pollutant. To reduce the risk of contamination, dyes should be treated before they are released into rivers. In the last 3 decades, membrane-based separations have become increasingly common and one of the most exciting 21st century technologies. In the process to refine a wide range of fluids from water and waste water to pharmaceutical and chemical materials, membrane technology is an advanced wastewater treatment technology. Membrane procedure is of greater interest because the unit volume is reduced, process water is recycled and useful materials are recovered for other uses. The current research work was focused on the careful analysis of literature, the research gap and the necessary findings for selecting polymers and the suitable additives for cationic dye removal. Polyurethane displayed a strong anti-fouling property that’s why PU has been chosen as a basic polymer. Since, PU did not provide all the required properties of fabricating membrane that’s why novel composites are blended with it as an additive. Thus, the APTES and MCM-41 based covalent bounded dual natured fillers are prepared that is mixed in appropriate amount (2.5%, 5%, 7.5% and 10%) with PU, which provides high surface area in low volume in the membrane matrix. FTIR analysis was used to elaborate the internal chemistry of polymer and amine/silica based filler, whereas AFM surface morphology described the homogenous distribution of compositional element in membrane blend via its 3D images. AFM technique is also used for grain analysis and surface roughness data. Detail antifouling properties with membrane dye resistance ability described that MCM-41/APTES based membranes just showed 10-11 % ir-reversible resistance with 88-89% flux recovery against dye contaminants. Negligible leaching, higher water adsorption and lower pore size and lesser surface roughness recommend the membrane to be used in dye separation filtration, two model dye name as crystal violet dye (MW: 407.979 g/mol) and Pink dye (MW: 879.86 g/mol) were selected for filtration processes. Results revealed that MCM-41/APTES membrane provided 82-87% clearance rate.
2-Deoxy-D-Ribose Releasing Chitosan/Collagen Based Pro-Angiogenic Skin Substitutes for Diabetic and Burn Wounds
(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-19) Muhammad Waqar Younas; SP19-R06-021; Dr. Muhammad Yar
Chronic diabetic foot ulcers and severe burn injuries (i.e., full-thickness burns) cause extensive damage and are often complicated to heal and are burden on the economy. Slow or delayed blood vessel formation is the main reason for the delayed or non-healing of wounds [1]. It is estimated that in the year 2015 almost 8.8% of adult peoples were suffered from diabetes and the number of the diabatic patient is expected to increase at an alarming rate of 10.4% up to the year 2040 world-wide [2]. Diabetic patients suffer from non-healing wounds and the expanding rate of diabatic patients will increase the threats of chronic wounds. The development of cost-effective materials that can support angiogenesis is highly desired to prepare advance wound dressings [3]. In the current research, we developed the chitosan-based hydrogels through the freeze gelation method and utilized them as a 2-Deoxy-D-ribose (2dDR) carrier dressing. 2-Deoxy-D-ribose (2dDR) is a simple polysaccharide having ability to up regulate the release of VEGF in a more controlled way to support wound healing phenomenon in slow healing diabetic wounds [4]. Release studies of 2dDR were measured by using Bial’s orcinol assay. Swelling studies were performed to investigate the solution absorption capacity. Mechanical testing was performed to study the flexibility and tensile strength. Results indicated the developed material could be utilized as a cost-effective pro-angiogenic dressing material for diabetic and burn wounds.
Fabrication and Characterization of Polymeric Aminopropyltriethoxysilane Silica-based Hemodialysis Membrane
(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-19) Muhammad Jawwad Ahmad; FA18-R06-030; Dr. Nawshad Muhammad; LHR TP 6504
Kidneys are an important part of human body. The function of kidneys is to remove toxic effluent and fluids from the blood and sustain the specific quantity of liquid in body to operate properly. When human kidney fail to work up to 90% either due to some disease or other reason, then patient body become loaded with toxic surplus. This can lead to kidney failure and even life intimidating if left untreated. There are some methods for the treatments of kidney failure in which the important one is hemodialysis therapy. In hemodialysis, human blood is passed through a hemodialysis machine, where most important component of the entire set up is semipermeable dialysis membrane, which has a tremendous impact on the quality and quantity to remove the unwanted uremic toxins from the blood of the patient who have been dealing with the kidney failure. Suitability of the hemodialysis membrane based on biocompatibility factor that depend on membrane chemical composition. Lower risk of death suffered to the patient when dialyzed with membranes that are highly biocompatible. Thus, current work is focused to develop a hemodialysis membrane based on novel formulations and methodology that is highly biocompatible when treated with real human body and also successfully removes the uremic toxins from the model solution of uremic toxins.
A Comparative Study of Different DFT Functionals on the Nonlinear Optical (NLO) Properties of Some NLO Prototypes
(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-19) Alina Waheed; SP19-R06-018; Dr. Mazhar Amjad Gilani; LHR TP 6521
he present study spotlights the fundamental insights about four different classes of functionals and their efficacy to calculate the nonlinear optical (NLO) and linear properties. For this study, urea and (p-NA) para-nitroaniline molecules are used up as reference organic molecules. For comparative analysis, there is a dire need of such database to be utilized by the researchers. We have reported a range of functionals including hybrid (B3LYP, PBE1PBE, BHandHLYP), meta-hybrid (M06, M06-2X, M06-HF, M06-L), long-range corrected (CAM-B3LYP, LC-BLYP, LC-B97D, LCB97D3) along with dispersion correction (ωB97, ωB97X, ωB97XD, HSEH1PBE). These groups are evaluated and their efficiency to calculate linear and NLO properties is graphically compared with each other. NLO properties including anisotropic and linear isotropic polarizabilities, dipole moment, second- and third- order polarizabilities were analysed using their corresponding groups and there functionals. The presented results will help researchers to compare their calculations for the properties of NLO in different species. The current study highlights the importance of different functionals and their methods to be employed on various organic and inorganic species to study and evaluate their hyperpolarizabilities. The dipole moment of urea has been found to be 5.14 D which is close to experimentally determined value of 4.56 D. Similarly, the respective experimental and theoretical values of average second order polarizability as calculated by ωB97XD are quite close to each other. Interestingly, similar values of LC-B97D and LC-B97D3 for all the calculated parameters are obtained corresponding to urea and p-NA. A good agreement has been noticed among geometries, total electronic dipole moments and NLO polarizabilities on comparative basis. In addition, the (MEP) molecular electrostatic potential and (FMO) frontier molecular orbital map analyses are executed for the visual insight of charge transfer and predicting the reactive sites. In short, the current work provides significant methods to study the dipole moment, bond lengths, bond angles, static and frequency dependent second order and third-order polarizabilities. linear isotropic and anisotropic polarizabilities. Hence, the present results will attract the scientific community to compare their experimental work on various organic species with our results of urea and p-NA. These compounds are widely used as reference species in experimental and theoretical appraisal in the field x of nonlinear and linear optics. The current investigation will evoke scientific interest regarding the promising comparison of NLO properties in various organic species which can be beneficial in modern hi-tech applications.
Carbon-based Nanomaterials for Electrocatalytic Oxidation of Methanol and Ethanol
(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-19) Salman Munawar; FA18-R06-022; Dr. Muhammad Javid Iqbal; LHR TP 6500
Fuel cells attract validation every day due to the important characteristics of Pt, Pd, Ru and Rh as the traditional catalysts, including no mobile portion and energy generation, but also because they are uncommon and costly, they also produce toxic, intermediate, and slow-cinematic reactions. In this study, CoSe/CNT material was prepared which is responsible for methanol oxidation reaction in methanol fuel cell. The CoSe/CNT material has been synthesized through using of selenium (Se) along with cobalt chloride hexahydrate. For this preparation, single step hydrothermal is applied. XRD confirmed the successful composite synthesis along with SEM. x Laterally, the synthesized material has showed remarkable use in electrochemical reaction such as oxidation reaction of methanol studies. The trustable technique such as cyclic voltammetry has been applied which confirmed that the methanol oxidation is a diffusion-controlled process and forward peak current and peak potential increase with the scan rate when varying between 25, 50, 100, 150 and 200 mV/s. This technique was performed in acidic medium on modified glassy carbon electrode (GCE) via three electrode electrochemical system. The oxidation reaction of methanol is catalyzed by CoSe@CNTs catalyst and remarkable current density with peak value of 6.4 mA/cm2 by using 0.6 potential with scan rate of 50mV/s. The lower charge transfer resistance Rct has been confirmed by using electrochemical impedance spectroscopy and catalyst was highly stable.
Computational Evaluation of Metal Doped Phosphorene-Nanosheets for Cancer Treatment
(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-19) Hira Karim; LHR TP 6508; Dr. Sobia Tabassum; LHR TP 6508
Cancer is known as one of the leading causes of human mortality. The cancer treatments also damage the healthy tissue. So effective theranostic treatments are required for efficient cancer therapy and safety of healthy tissue. Phosphorene is a great material of interest to develop efficient targeted drug delivery system and imaging guided thermal therapy for cancer curing. Metal doping in a material is offered to tune its properties. In this work, effect of group II A metals on targeted delivery of anti-cancer drug, photoimaging (image guided cancer treatment) and photothermal treatment (thermal killing of cells by employing near infrared (NIR) light of doped phosphorene are evaluated via DFT method. The adsorption energies, quantum molecular properties, Atoms in Molecules (AIM) analysis, and Natural Bond Orbital (NBO) analysis of drug loaded pristine and doped phosphorene complexes were explored to understand the type of events in their interactions. The thermodynamic data confirms the exothermic and spontaneous nature of adsorption. The doped complexes showed better adsorption than pristine complex. The polarity was found to increase in doped complexes which is essential for driving in biological systems. Drug adsorption and doping have decreased the chemical potential and electrophilicity index while increased the softness of pristine phosphorene and doped phosphorene. The NBO data indicated the flow of charge from drug to nanosheet. Doping has made suitable the charge transfer and associated interaction. This interaction is strong in neutral pH. At acidic pH, in cancerous tissue environment drug will be protonated and will lose this interaction. These interactions were further investigated by Quantum Theory of Atoms in Molecules (QTAIM) analysis, revealing strong covalent interactions in all doped complexes except for one Mg-O bond in Mg-doped complex which owns strong electrostatic interactions. TD-DFT study showed lowering of band gap and shifting of λmax towards NIR region which is very useful for photothermal and image guided therapy. The Surface-Enhanced Raman Scattering (SERS) analysis revealed that doped systems effectively enhanced the Raman signals. All these properties supported the potential use of doped phosphorene complexes for photoimaging and photothermal killing of cancer cells.