468 research outputs found

    Adsorption of endocrine disrupting compounds and other emerging contaminants using lignocellulosic biomass-derived porous carbons: A review

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    Hydrochars from lignocellulose biomass have received an upsurge of interest in different fields, especially in the area of adsorption. Hydrothermally produced hydrochars are effective adsorbents for removing different pollutants, and they serve as a cheap and sustainable raw material for subsequent activation to achieve porous activated carbons (ACs) with large surface areas. In this review, recent studies on preparation and characteristics of adsorbents in terms of hydrochars from lignocellulose biomass and their derived ACs are presented and discussed. The application of these adsorbents for the removal of endocrine disrupting chemicals and other emerging pollutants is included. The sources and classification, adsorption isotherm, kinetics, and mechanism of these pollutants and the capability of regenerating and reusing cheap and efficient adsorbents such as hydrochar and ACs are also discussed. This review identifies knowledge gaps and proposes insights into new directions for improving the applications of hydrochar and ACs as adsorbents.The publication of this article was funded by the Qatar National Library.Scopu

    Review on recent progress in chitosan/chitin-carbonaceous material composites for the adsorption of water pollutants

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    Chitosan and chitin are categorized as low cost, renewable and eco-friendly biopolymers. However, they have low mechanical properties and unfavorable pore properties in terms of low surface area and total pore volume that limit their adsorption application. Many studies have shown that such weaknesses can be avoided by preparation of composites with carbonaceous materials from these biopolymers. This article provides a systematic review on the preparation of chitosan/chitin-carbonaceous material composites. Commonly used carbonaceous materials such as activated carbon, biochar, carbon nanotubes, graphene oxide and graphene to prepare composites are discussed. The application of chitosan/chitin-carbonaceous material composites for the adsorption of various water pollutants, and the regeneration and reusability of adsorbents are also included. Finally, the challenges and future prospects for the adsorbents applied for the adsorption of water pollutants are summarized.The publication of this article was funded by the Qatar National Library .Scopu

    Aquatic resources valuation and policies for poverty elimination in the lower Mekong basin: final report volume 1 project implementation and outcomes

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    This report presents the final outputs of the project on "Aquatic resources valuation and policies for poverty elimination in the Lower Mekong Basin". Volume 1 summarizes the implementation process, outcomes and key lessons of the project. The project was implemented in partnership with the Dept of Fisheries, Cambodia. It was developed to improve understanding of the economic and social values of aquatic resources, as a step towards improving institutional and policy processes in the Lower Mekong Basin so that resource management decisions better reflect the interests of the rural poor.Resource management, Aquatic environment, Living resources, Cambodia, Southeast, Southeast Asia, Mekong R.,

    Analysing count data of Butterflies communities in Jasin, Melaka: a poisson regression analysis

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    Counting outcomes normally have remaining values highly skewed toward the right as they are often characterized by large values of zeros. The data of butterfly communities, had been taken from Jasin, Melaka and consists of 131 number of subject visits in Jasin, Melaka. In this paper, considering the count data of butterfly communities, an analysis is considered Poisson regression analysis as it is assumed to be an alternative way on better suited to the counting process. This research paper is about analysing count data from zero observation ecological inference of butterfly communities in Jasin, Melaka by using Poisson regression analysis. The software for Poisson regression is readily available and it is becoming more widely used in many field of research and the data was analysed by using SAS software. The purpose of analysis comprised the framework of identifying the concerns. Besides, by using Poisson regression analysis, the study determines the fitness of data for accessing the reliability on using the count data. The finding indicates that the highest and lowest number of subject comes from the third family (Nymphalidae) family and fifth (Hesperidae) family and the Poisson distribution seems to fit the zero values

    CFTR Functions as a Bicarbonate Channel in Pancreatic Duct Cells

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    Pancreatic duct epithelium secretes a HCO3−-rich fluid by a mechanism dependent on cystic fibrosis transmembrane conductance regulator (CFTR) in the apical membrane. However, the exact role of CFTR remains unclear. One possibility is that the HCO3− permeability of CFTR provides a pathway for apical HCO3− efflux during maximal secretion. We have therefore attempted to measure electrodiffusive fluxes of HCO3− induced by changes in membrane potential across the apical membrane of interlobular ducts isolated from the guinea pig pancreas. This was done by recording the changes in intracellular pH (pHi) that occurred in luminally perfused ducts when membrane potential was altered by manipulation of bath K+ concentration. Apical HCO3− fluxes activated by cyclic AMP were independent of Cl− and luminal Na+, and substantially inhibited by the CFTR blocker, CFTRinh-172. Furthermore, comparable HCO3− fluxes observed in ducts isolated from wild-type mice were absent in ducts from cystic fibrosis (ΔF) mice. To estimate the HCO3− permeability of the apical membrane under physiological conditions, guinea pig ducts were luminally perfused with a solution containing 125 mM HCO3− and 24 mM Cl− in the presence of 5% CO2. From the changes in pHi, membrane potential, and buffering capacity, the flux and electrochemical gradient of HCO3− across the apical membrane were determined and used to calculate the HCO3− permeability. Our estimate of ∼0.1 µm sec−1 for the apical HCO3− permeability of guinea pig duct cells under these conditions is close to the value required to account for observed rates of HCO3− secretion. This suggests that CFTR functions as a HCO3− channel in pancreatic duct cells, and that it provides a significant pathway for HCO3− transport across the apical membrane

    Observation of hard scattering in photoproduction events with a large rapidity gap at HERA

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    Events with a large rapidity gap and total transverse energy greater than 5 GeV have been observed in quasi-real photoproduction at HERA with the ZEUS detector. The distribution of these events as a function of the γp\gamma p centre of mass energy is consistent with diffractive scattering. For total transverse energies above 12 GeV, the hadronic final states show predominantly a two-jet structure with each jet having a transverse energy greater than 4 GeV. For the two-jet events, little energy flow is found outside the jets. This observation is consistent with the hard scattering of a quasi-real photon with a colourless object in the proton.Comment: 19 pages, latex, 4 figures appended as uuencoded fil
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