Syed Shahabuddin

Synthesis of chitosan grafted-polyaniline/Co3O4 nanocube nanocomposites and their photocatalytic activity toward methylene blue dye degradation

In the present investigation, chitosan-grafted-polyaniline copolymer (ChGP) and Co3O4 nanocube-doped ChGP nanocomposites have been successfully synthesised via oxidative-radical copolymerisation using ammonium persulfate in an acidic medium for the photocatalytic degradation of methylene blue dye. The prepared nanocomposites were characterised by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), UV-vis spectroscopy, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). FESEM and TEM images confirmed the formation of Co3O4 nanocubes and a crosslinked polymeric network. The photocatalytic activities of ChGP and Co3O4 nanocube-doped copolymers were evaluated by monitoring the degradation of methylene blue dye under UV illumination. The degradation efficiency of the copolymer photocatalysts that were doped with Co3O4 nanocubes was higher than that of the undoped copolymer. Furthermore, the nanocomposite with 2 wt% Co3O4 nanocubes with respect to aniline was an optimum photocatalyst, with an 88% degradation efficiency after 180 minutes of irradiation under UV light.

Synthesis and characterization of Co3O4 nanocube-doped polyaniline nanocomposites with enhanced methyl orange adsorption from aqueous solution

In the present study, Co3O4 nanocube-doped polyaniline nanocomposites have been successfully synthesised via an in situ oxidative polymerisation technique using ammonium persulfate (APS) as an oxidant in acidic medium for efficient removal of methyl orange (MO) from aqueous solution. Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), Brunauer–Emmett–Teller analysis (BET) and Fourier transform infrared spectroscopy (FT-IR) measurements were used to characterise the prepared nanocomposites. The adsorption efficiencies of the PANI homopolymer and Co3O4 nanocube-doped nanocomposites were evaluated by monitoring the adsorption of methyl orange model dye from aqueous solution. The results revealed that the adsorption efficiency of the nanocomposites that were doped with Co3O4 nanocubes was higher than that of the undoped PANI and the adsorption kinetics followed a pseudo-second order reaction. Moreover, the nanocomposite with 4 wt% Co3O4 nanocubes with respect to aniline exhibited a superior adsorption capacity (107 mg g−1) as compared to other absorbents.

SrTiO3 Nanocube-Doped Polyaniline Nanocomposites with Enhanced Photocatalytic Degradation of Methylene Blue under Visible Light

The present study highlights the facile synthesis of polyaniline (PANI)-based nanocomposites doped with SrTiO3 nanocubes synthesized via the in situ oxidative polymerization technique using ammonium persulfate (APS) as an oxidant in acidic medium for the photocatalytic degradation of methylene blue dye. Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), UV–Vis spectroscopy, Brunauer–Emmett–Teller analysis (BET) and Fourier transform infrared spectroscopy (FTIR) measurements were used to characterize the prepared nanocomposite photocatalysts. The photocatalytic efficiencies of the photocatalysts were examined by degrading methylene blue (MB) under visible light irradiation. The results showed that the degradation efficiency of the composite photocatalysts that were doped with SrTiO3 nanocubes was higher than that of the undoped polyaniline. In this study, the effects of the weight ratio of polyaniline to SrTiO3 on the photocatalytic activities were investigated. The results revealed that the nanocomposite P-Sr500 was found to be an optimum photocatalyst, with a 97% degradation efficiency after 90 min of irradiation under solar light.

Removal of endocrine disruptor di-(2-ethylhexyl)phthalate by modified polythiophene-coated magnetic nanoparticles: characterization, adsorption isotherm, kinetic study, thermodynamics

Core–shell magnetic nanoparticles have received significant attention and are actively explored due to their prospective applications. In the current study, superparamagnetic nanosorbent poly(phenyl(4-(6-thiophen-3-yl-hexyloxy)-benzylidene)-amine)/Fe3O4 nanoparticles (Fe3O4@P3TArH) was successfully synthesized via a simplistic method for the enhanced extraction of a potent endocrine disruptor, di-(2-ethylhexyl)phthalate (DEHP). The synthesized materials were characterized by Fourier transform infra-red (FTIR), X-ray diffractometry (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). The extraction efficiencies of the synthesized sorbent materials were evaluated by monitoring the extraction of DEHP from aqueous solution. Removal of DEHP using Fe3O4@P3TArh was found to be pH and temperature dependent with a maximum adsorption capacity found to be at 298.15 K at pH 7 and the adsorption kinetics followed a pseudo second-order kinetics model. Thermodynamic studies revealed that adsorption occurred heterogeneously on the adsorption sites, and adsorption of di-(2-ethylhexyl)phthalate onto Fe3O4@P3TArh was found to be spontaneous, feasible, ordered, and exothermic. The activation energy was determined to be −40.6 kJ mol−1, which indicated the adsorption process was physisorption.

Piperazine clubbed with 2-azetidinone derivatives suppresses proliferation, migration and induces apoptosis in human cervical cancer HeLa cells through oxidative stress mediated intrinsic mitochondrial pathway

Piperazine scaffolds or 2-azetidinone pharmacophores have been reported to show anti-cancer activities and apoptosis induction in different types of cancer cells. However, the mechanistic studies involve in induction of apoptosis addressing these two moieties for human cervical cancer cells remain uncertain. The present study emphasizes on the anti-proliferating properties and mechanism involved in induction of apoptosis for these structurally related azoles derivatives in HeLa cancer cells. 1-Phenylpiperazine clubbed with 2-azetidione derivatives (5a–5h) were synthesized, characterized using various spectroscopic techniques and evaluated for their in-vitro anti-proliferative activities and induction of apoptosis. Further, we also evaluated oxidative stress generated by these synthetic derivatives (5a–5h). Cell viability studies revealed that among all, the compound N-(3-chloro-2-(3-nitrophenyl)-4-oxoazetidin-1-yl)-2-(4-phenylpiperazin-1-yl) acetamide 5e remarkably inhibited the growth of HeLa cells in a concentration dependent manner having IC50 value of 29.44u2009±u20091.46xa0µg/ml. Morphological changes, colonies suppression and inhibition of migration clearly showed the antineoplasicity in HeLa cells treated with 5e. Simultaneously, phosphatidylserine externalization, DNA fragmentation and cell-cycle arrest showed ongoing apoptosis in the HeLa cancer cells induced by compound 5e in concentration dependent manner. Additionally, generation of intracellular ROS along with the decrease in mitochondrial membrane potential supported that compound 5e caused oxidative stress resulting in apoptosis through mitochondria mediated pathway. Elevation in the level of cytochrome c and upregulation in expression of caspase-3 clearly indicated the involvement of the intrinsic pathway of programmed cell death. In brief; compound 5e could serve as a promising lead for the development of an effective antitumor agent.Graphical Abstract

Equilibrium, Kinetic and Thermodynamic Study of Magnetic Polyaniline/Graphene Oxide Based Nanocomposites for Ciprofloxacin Removal from Water

In the present study, an adsorbent based on polyaniline-magnetic graphene oxide nanocomposite (MGO@PANI) was synthesized via in situ polymerization of an aniline monomer using ammonium persulfate as an oxidant in acidic medium for enhanced removal of ciprofloxacin (CIP) from aqueous solution. The surface functionality, morphology and elemental composition of the newly synthesized MGO@PANI were analyzed by FT-IR, FE-SEM, and EDX techniques. The adsorption efficacy of MGO@PANI was evaluated by monitoring the adsorption behavior of CIP antibiotic from aqueous samples. The effective factors on CIP adsorption such as solution pH, adsorbent dosage, contact time, concentration and temperature were investigated. The results revealed that MGO@PANI exhibits high adsorption efficiency with 97% removal of CIP (pH 6, dosage 20xa0mg, time 30xa0min at room temperature). The experimental data were well fitted to Freundlich adsorption isotherm suggesting multilayer pattern for adsorption process and the adsorption kinetics followed pseudo-second-order kinetics. Additionally, the thermodynamic study revealed that the CIP adsorption onto MGO@PANI was endothermic and indicated chemisorption mechanism.

Palm Fatty Acid Functionalized Fe3O4 Nanoparticles as Highly Selective Oil Adsorption Material

The present work highlights the facile synthesis of hydrophobic palm fatty acid functionalized Fe3O4 nanoparticles (MNP-FA) for the efficient removal of oils from the surface of water. An intense hydrophobic layer was introduced on the surface of Fe3O4 nanoparticles functionalized by the palm fatty acid obtained from the hydrolysis of palm olein. Scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), Energy dispersive X-ray spectroscopy (EDX) and water contact angle analysis (WCA) measurements were used to characterize the newly fabricated palm fatty acid adorned magnetic Fe3O4 nanoparticles (MNP-FA). The obtained results confirmed the successful synthesis of palm fatty acid-functionalized magnetic nanoparticles. Oil removal tests performed with MNP-FA revealed that this newly prepared material could selectively adsorb lubricating oil up to 3.5 times of the particles weight while completely repelling water. The main parameters affecting the adsorption of oil i.e., sorption time, mass of sorbent and pH of water were optimized.

Kinetic and equilibrium adsorption of lead from water using magnetic metformin-substituted SBA-15

The present investigation demonstrates the successful and easy approach for the synthesis of magnetic amine-substituted SBA-15 nanocomposite for effective removal of lead (Pb2+) ions via adsorption from aqueous environment. The nano-adsorbents were synthesized by effective doping of magnetic nanoparticles over synthesized SBA-15 metformin (Met) to obtain MNPs/SBA-15-Met nanocomposites. The synthesized nanocomposites were characterized by Fourier transform infrared spectroscopy (FT-IR), EDX, X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Due to the presence of nitrogen atom containing backbone, the MNPs-SBA-15-Met nanocomposite has demonstrated high adsorption capacity (333 mg g−1) toward Pb(II) ions as compared to the pure SBA-15. Experimental data was evaluated with isotherm models and non-linear type I model was well fitted on data. The effective parameters for adsorption process such as effect of pH, salt, adsorbent dosage, contact time, initial concentration and temperature were studied and optimized. The studies indicated that at pH range of 6, the percentage removal of Pb(II) was found to be 96% at room temperature. The FTIR spectroscopy and EDX results of the nanocomposites after the Pb(II) adsorption (MNPs/SBA-15-Met-Pb2+) specified that adsorption occurred probably through electrostatic interaction between Pb(II) ions and N groups (amine & amide).

Synthesis of Well-Defined Three-Arm Star-Branched Polystyrene through Arm-First Coupling Approach by Atom Transfer Radical Polymerization

Here we describe a simple route to synthesize three-arm star-branched polystyrene. Atom transfer radical polymerization technique has been utilized to yield branched polystyrene involving Williamson coupling strategy. Initially a linear polymeric chain of predetermined molecular weight has been synthesized which is further end-functionalized into a primary alkyl bromide moiety, a prime requisition for Williamson reaction. The end-functionalized polymer is then coupled using 1,1,1-tris(4-hydroxyphenyl)ethane, a trifunctional core molecule, to give well-defined triple-arm star-branched polystyrene.

Fabrication and Characterization of an Electrospun PHA/Graphene Silver Nanocomposite Scaffold for Antibacterial Applications

Many wounds are unresponsive to currently available treatment techniques and therefore there is an immense need to explore suitable materials, including biomaterials, which could be considered as the crucial factor to accelerate the healing cascade. In this study, we fabricated polyhydroxyalkanoate-based antibacterial mats via an electrospinning technique. One-pot green synthesized graphene-decorated silver nanoparticles (GAg) were incorporated into the fibres of poly-3 hydroxybutarate-co-12 mol.% hydroxyhexanoate (P3HB-co-12 mol.% HHx), a co-polymer of the polyhydroxyalkanoate (PHA) family which is highly biocompatible, biodegradable, and flexible in nature. The synthesized PHA/GAg biomaterial has been characterized by field emission scanning electron microscopy (FESEM), elemental mapping, thermogravimetric analysis (TGA), UV-visible spectroscopy (UV-vis), and Fourier transform infrared spectroscopy (FTIR). An in vitro antibacterial analysis was performed to investigate the efficacy of PHA/GAg against gram-positive Staphylococcus aureus (S. aureus) strain 12,600 ATCC and gram-negative Escherichia coli (E. coli) strain 8739 ATCC. The results indicated that the PHA/GAg demonstrated significant reduction of S. aureus and E. coli as compared to bare PHA or PHA- reduced graphene oxide (rGO) in 2 h of time. The p value (p < 0.05) was obtained by using a two-sample t-test distribution.