1,721,025 research outputs found
Preparation of TiO2/SiO2 ceramic membranes via dip coating for the treatment of produced water
No full textProduced water, a by-product generated from the oil and gas extraction processes, represents a major challenge in the oil and gas industry as it is generally characterized with a very high salinity and oil content. Currently used ceramic membranes for oil-water separation suffer from the low water flux in spite of their several distinctive advantages. To overcome this limitation and to increase the water flux and oil rejection, commercial ceramic TiO2 membranes were dip coated with silica (SiO2) nanoparticles at different concentrations of 0.25, 0.50, 0.75, and 1.0 wt %. Coated membranes were characterized using scanning electron microscopy (SEM), energy-dispersive x-ray sSpectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR) and Raman Spectroscopy and contact angle. Results showed that SiO2 nanoparticles were successfully deposited on the surface of the ceramic membranes confirming the dip coating approach. Furthermore, water flux of 817, 2724, 3636, 627, and 1292 L m−2 h−1 (LMH) was reported at control, 0.25, 0.50, 0.75 and 1.0 wt%; respectively. Also, contact angle reported 75°, 50°, 40°, 24°, 0° at control, 0.25, 0.50, 0.75 and 1.0 wt%; respectively. Finally, total organic carbon (TOC) in the treated water samples reported 100, 28, 11, 9, 10, 13 mg L−1 at control, 0.25, 0.50, 0.75 and 1.0 wt%, respectively. This study can be a preliminary to further studies that accommodate industry-like conditions to help decrease the gap between ideal laboratory setups and harsh real life conditions to fully optimize and exploit the advantages of ceramic membranes in oil-water separation
Preparation of novel polyvinylidene fluoride (PVDF)-Tin(IV) oxide (SnO2) ion exchange mixed matrix membranes for the removal of heavy metals from aqueous solutions
No full textGlobal consideration has been growing recently to tackle the toxic and carcinogenic effects of heavy metal presence in water streams. In this work, novel polyvinylidene fluoride (PVDF)/tin(IV) oxide (SnO2) ion exchange membranes were prepared via the phase inversion method and their performance and properties were analyzed. The results showed that the addition of SnO2 nanoparticles (SnNPs) led to an improvement in the pure water flux from 25.5 ± 1.5 L/m2.h in the pristine PVDF membrane to 250.5 ± 12.5 L/m2·h in the 1.00 wt% PVDF/SnNPs membranes. This was related to the increase in the overall porosity and hydrophilicity of the membranes. Additionally, the 0.25 wt% PVDF/SnNPs membrane reported the highest tensile strength equal to 21.3 ± 0.6 MPa compared to only 14.3 ± 0.4 MPa in the pristine PVDF membrane. Lastly, the maximum removal of Pb2+, Cu2+, Zn2+, Cd2+, and Ni2+ was achieved by the 0.25 wt% PVDF/SnNPs membrane with around 93.9 ± 1.7, 92.8 ± 1.3, 82.3 ± 2.0, 70.7 ± 1.1, and 63.9 ± 1.5%, respectively, compared to 93.5 ± 1.3, 92.9 ± 1.7, 68.3 ± 2.1, 50.3 ± 1.8, and 50.3 ± 1.4% in the pristine PVDF membrane. The mechanism of removal was predicted to be a combination of ion exchange/adsorption, inner-sphere complexations and electrostatic attraction between the metal ions and the SnNPs. Such a PVDF/SnNPs membranes have great potential in the field of wastewater treatment
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Facile synthesis and characterization of super-hydrophobic Fe2O3 for membrane distillation
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Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Investigation of Graphene Oxide (GO)- Manganese Oxide (MnO2) Nanocomposite in Metal Ions Adsorption from Wastewater
No full textAsymmetrical ultrafiltration membranes based on polylactic acid for the removal of organic substances from wastewater
No full textThe continued use of non-biodegradable polymeric-based membranes for water purification has led to an unsustainable accumulation of waste at disposal, resulting in various environmental problems. In this study, ecofriendly asymmetric ultrafiltration (UF) membranes were fabricated from polylactic acid (PLA) with different polymer concentrations using the phase inversion method. The fabricated membranes were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), contact angle, porosity, and pore size analysis. Permeate flux and organic matter (bovine serum albumin (BSA)) rejection were evaluated using synthetic wastewater. The anti-fouling properties of PLA membranes were investigated through static adsorption and dynamic filtration of BSA. Furthermore, the performance of the best performing PLA membrane was evaluated via chemical oxygen demand (COD) rejection as well as membrane fouling using raw municipal wastewater obtained from a local wastewater treatment plant (WWTP) in Abu Dhabi (UAE). The results indicated that increasing the PLA concentration to 20 wt% improved BSA removal from synthetic and raw wastewaters by up to 92 and 89%, respectively, in addition to improving the membrane antifouling property. The post-filtration and after cleaning FT-IR spectra revealed high antifouling property with no detection of BSA peaks, SEM images confirmed the reduction in membrane's pore size as PLA concentration increased, resulting in enhancing the antifouling properties of the membranes. In conclusion, this study demonstrated that PLA-UF membranes could be a viable eco-friendly alternative to traditional crude oil-derived membranes
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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