Preparation and Characterization of Pd Modified TiO 2

Abstract: TiO2 fiberswere prepared through electrospinning of poly methyl methacrylate (PMMA)and titaniumisopropoxide (TIP) solution followed by calcination of fibers in air at 500∘C. Cetyltrimethylammonium bromide (CTAB) protected palladium nanoparticles (Pd NPs) prepared through reduction method were successfully adsorbed on the TiO2 nanofibers (NF). Combined studies of X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) indicated that the synthesized Pd/TiO2 had anatase. BET indicated that the synthesized TiO2 and Pd/TiO2 had a surface area of 53.4 and 43.4m2/g, respectively.The activity and selectivity of 1mol% Pd/TiO2 in the Heck reaction have been investigated towards theMizoroki-Heck carbon–carbon cross-coupling of bromobenzene (ArBr) and styrene. Temperature, time, solvent, and base were optimized and catalyst was recycled thrice. 1H NMR and 13C NMR indicated that stilbene, a known compound from literature, was obtained in various Heck reactions at temperatures between 100∘C and 140∘C but the recyclability was limited due to some palladium leaching and catalyst poisoning which probably arose from some residual carbon from the polymer. The catalyst was found to be highly active under air atmosphere with reaction temperatures up to 140∘C. Optimized reaction condition resulted in 89.7% conversions with a TON of 1993.4 and TOF value of 332.2 hr−1

Development of Ag/GO Incorporated onto PES Membrane with Improved Anti-Fouling Property

Graphene and its derivatives have got increasingly application interests emanating from its unique properties. This work reports silver-graphene oxide sheets (Ag-GO) composite synthesis and then incorporated into Polyethersulfone (PES) casting solution. The composite casting mixtures were cast via phase inversion method. Graphene and its derivatives were characterised by ATR/FTIR, Raman, XRD and TEM. The morphology and performance of the neat PES and composite PES membranes were characterised by SEM, AFM, CA, permeation flux, protein (BSA) rejection, antifouling and antibacterial tests. The composite membranes exhibited a slightly higher permeation flux and then gradual decreased compared to neat PES membranes. However, the antifouling tests revealed that the composite membranes with Ag particles showed a preferable antifouling performance. The antibacterial tests confirmed that the composite membranes exhibited a effective antibacterial performance against both gram-positive (E. coli) and gram-negative (S. Aureus) strains

Rising profile on the use of metal–organic frameworks (MOFs) for the removal of heavy metals from the environment: an overview

Abstract This review study is dealing with the recent advances and developments in the metal–organic framework (MOF) materials especially in the aspect of environmental remediation of heavy metals. Its application in some area of technological and mechanical advancement was also considered. The process of its synthesis and characterization was also put into consideration. Metal-organic frameworks can be said to be an exciting new class of nanoporous crystalline materials containing a metal as its central ion surrounded by organic ligands. An overwhelming characteristic of MOFs lies in its surface area which is amazingly large, exceeding those of known best activated carbons and zeolites. There is an increasingly high demand in the application of MOFs for a multitude of environmental uses or application to be used for capturing and separating various unwanted or even environmentally harmful chemicals, elements or materials. The advantage of MOFs over other known adsorbent materials, such as zeolites and carbon black, is that it possesses a far greater surface area along with amazingly great pore properties. In this review the synthesis and characterization of MOFs, the fate of heavy metals, the application of MOFs in heavy metals remediation and other means of heavy metals remediation are well discussed

Impact of pyridyl moieties on the inhibitory properties of prominent acyclic metal chelators against metallo-β-lactamase-producing Enterobacteriaceae : investigating the molecular basis of acyclic metal chelators' activity

Carbapenem-resistant Enterobacteriaceae (CREs)-mediated infections remain a huge public health concern. CREs produce enzymes such as metallo-β-lactamases (MBLs), which inactivate β-lactam antibiotics. Hence, developing efficient molecules capable of inhibiting these enzymes remains a way forward to overcoming this phenomenon. In this study, we demonstrate that pyridyl moieties favor the inhibitory activity of cyclic metal-chelating agents through in vitro screening, molecular modeling, and docking assays. Di-(2-picolyl) amine and tris-(2-picolyl) amine exhibited great efficacy against different types of MBLs and strong binding affinity for NDM-1, whereas 2-picolyl amine did not show activity at a concentration of 64 mg/L in combination with meropenem; it further showed the lowest binding affinity from computational molecular analysis, commensurating with the in vitro screening assays. The findings revealed that the pyridyl group plays a vital role in the inhibitory activity of the tested molecules against CREs and should be exploited as potential MBL inhibitors

Human and ecological risk assessments of potentially toxic elements in sediments around a pharmaceutical industry

Potentially toxic elements (PTEs) in sediment can be highly hazardous to the environment and public health. This study aimed to assess the human and ecological risks of PTEs in sediments around a pharmaceutical industry in Ilorin, Nigeria. Physicochemical parameters and the concentrations of lead (Pb), chromium (Cr), cadmium (Cd), cobalt (Co), arsenic (As), and nickel (Ni) were analyzed in sediment samples collected from seven locations in the wet and dry seasons. Standard two-dimensional principal component analysis (PCA) and risk assessments were also conducted. The concentrations of Pb, Co, Ni, Cr, Cd, and As in the sediments ranged from 0.001 to 0.031 mg/kg, 0–0.005 mg/kg, 0.005–0.012 mg/kg, 0.001–0.014 mg/kg, 0.005–0.024 mg/kg, and 0.001–0.012 mg/kg, respectively. The mean concentrations of the total PTEs content were found in decreasing order of concentration: Pb > Cd > Ni > Cr > As > Co. PCA showed that some of the PTEs were highly concentrated in samples obtained at other locations as well as at the discharge point. The Hazard Index was mostly <1 across locations, indicating little to no probable non-cancerous effect. However, the incremental lifetime cancer risk for arsenic and nickel was high and required attention. The ecological risk assessment showed that lead and arsenic were the major PTEs pollutants in all locations. The study identifies PTEs profiles in sediments and emphasises the necessity of continual monitoring and action to stop long-term negative impacts on the local environment and public health