1,721,063 research outputs found
Efficiency of Membrane Technology Activated Charcoal and a Clay Micelle Complex for the Removal of Ibuprofen and Mefenamic Acid.
No full textKinetic studies on the stability of two non-steroids anti-inflammatory drugs (NSAIDs), ibuprofen and mefenamic
acid, in pure water and activated sludge indicated that both pharmaceuticals were resistant to degradation for one
month. The efficiency of sequential advanced membrane technology wastewater treatment plant towards removal of
both drugs from wastewater was investigated. The sequential system included activated sludge, ultrafiltration
(hollow fiber membranes with 100 kDa cutoff, and spiral wound membranes with 20 kDa cutoff), activated carbon
column and reverse osmosis (RO). The overall performance of the integrated plant demonstrated complete removal
of ibuprofen and mefenamic acid from spiked wastewater samples. Activated carbon column was the most effective
component in removing these NSAIDs with a removal efficiency of 98.8% for both ibuprofen and mefenamic acid.
Batch adsorption of both NSAIDs by activated charcoal and a composite micelle (octadecyltrimethylammonium
(ODTMA)–clay (montmorillonite) was determined at 25 ̊C. The results revealed that both adsorptions fit Langmuir
isotherm with Qmax of 66.7 mg/g and 62.5 mg/g for ibuprofen using activated carbon and clay-micelle complex,
respectively, and with Qmax of 90.9 mg/g and 100.0 mg/g for mefenamic acid using activated charcoal and claymicelle
complex, respectively. These results suggest that an integration of ODTMA-clay-micelle complex column in
wastewater treatment plant is highly promising and can lead to an improvement of the removal efficiency of these
drugs from wastewater
Removal of Two NSAIDs: Naproxen and Diclofenac and a Heavy Metal Cr (VI) by Advanced Membranes Technology.
Full text linkODTMA-micelle-clay complex as an efficient adsorbent was prepared from a cationic surfactant,
octadecyltrimethylammonium (ODTMA) and a negatively charged clay (montmorillonite). It is characterized with a positive charge
and large hydrophobic sites. The micelle- clay complex was investigated towards removal of the ant-inflammatory drugs (NSAIDs),
Diclofenac and Naproxen and a heavy metal Cr (VI) as part of comprehensive evaluation study to utilize this adsorbent in advanced
wastewater treatment technology.
Stability studies demonstrated that while Diclofenac potassium was completely stable in fresh water and in sludge Naproxen
underwent biodegradation in sludge to provide O-desmethyl naproxen (DMN) as its single metabolite.
Al-Quds Wastewater Treatment Plant (WWTP) which includes ultrafiltration (UF) (hollow fiber HF and spiral wound SW)
membranes, activated carbon (AC) and reverse osmosis (RO) has demonstrated high removal efficiency toward these two NSAIDs and
Naproxen metabolite (DMN). Furthermore, the filtration results by Al-Quds WWTP revealed that the UF-HF membrane was not
efficient in removing the three studied pollutants from wastewater. In contrast, the RO and AC membranes were found to be quite
efficient in removing (100%) all studied pharmaceuticals.
The column filtration experiments with a mixture of sand and ODTMA-micelle-clay complex as adsorbent indicated 100% removal of
the adsorbates, Diclofenac and Naproxen and Naproxen metabolite (SMN). Similarly, ODTMA-micelle-clay complex was found to
completely remove the heavy metal Cr (VI) from its aqueous solutions at ambient pH and temperature
Toward Zero Liquid Discharge from Integrated Advanced Wastewater Treatment Plant
Full text linkWater is considered among the most important, vital and crucial resources on earth. It is one of the basic ingredients
utilized by living organisms and it is essential for achieving economic and social development in all countries over the world. The
Mediterranean Countries, such as Palestine suffer from scarcity of fresh water and a significant water shortage while the demand of
clean water is increasing. The water shortage can be attributed to different factors including agriculture consumption,
industrialization, over pump of fresh water from aquifers, urbanization and socioeconomic development. The use of recycled water
could help solving part of the region’s water problems. Moreover, many lands in the Mediterranean Countries, including Palestine,
are affected by incoming desertification processes, which hinder the development and conservation of a normal agricultural and
touristic economy. The specific problems to be addressed in the near future are the fresh water shortage and quality and the use of the
recycled water to fill part of the gap.
In this paper we discuss different approaches for wastewater recycling and water purification.
The treatment of wastewater is capable of generating new water resources as an alternative for water shortage, for reuse in
agriculture, and for protection of the ground water from pollution and health hazardous
Stability and removal of spironolactone from wastewater
Full text linkStability and removal of spironolactone (SP) from wastewater produced at Al-Quds University Campus were investigated. Kinetic
studies on both pure water and wastewater coming from secondary treatment (activated sludge) demonstrated that the potassiumsparing
diuretic (water pill), spironolactone, underwent degradation to its hydrolytic derivative, canrenone, in both media. The firstorder
hydrolysis rate of SP in activated sludge at 25C (3.80 £ 10¡5 s¡1) was about 49-fold larger than in pure water (7.4 £ 10¡7 s¡1). The overall performance of the wastewater treatment plant (WWTP) installed in the University Campus was assessed showing that more than 90% of spiked SP was removed together with its newly identified metabolites. In order to look for a technology to supplement or replace ultra-filtration membranes, the effectiveness of adsorption and filtration by micelle-clay filters for removing
SP was tested in comparison with activated charcoal. Batch adsorption in aqueous suspensions was well described by Langmuir
isotherms, showing a better removal by the micelle-clay material. Filtration of SP water solutions by columns filled with a mixture of
sand and a micelle-clay complex showed complete removal of the drug at concentrations higher than in sand/activated-charcoal
filled filter
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
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
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
Removal of Chlorpyrifos using micelle clay complex and advanced treatment technology
Full text linkn this study, the stability of chlorpyrifos, a known pesticide, in fresh water and sludge was investigated. The results showed that chlorpyrifos underwent hydrolysis in both media to give two main metabolites: 3,5,6-trichoro-2-pyridiniol (TCP) and diethylthiophosphoric acid (DETP). The hydrolysis reaction in both media was found to follow first-order kinetics with a rate constant of 7.10 × 10−8 (R2 = 0.999) in pure water and of 9.30 × 10−8 (R2 = 0.996) in sludge. Chlorpyrifos degradation’s half-life value in pure water was 112 d and in sludge was 85.9 d. The efficiency of Al-Quds University wastewater treatment plant demonstrated that the ultrafiltration-hollow fiber unit (UF-HF) was insufficient in removing chlorpyrifos from spiked secondary treated wastewater samples, whereas the combination of ultrafiltration-spiral wound unit (UF-SW) followed by activated carbon (AC) column was quite efficient and yielded a complete removal of the pesticide. Batch adsorption experiments using either AC or micelle–clay complex were performed and the experimental results were fitted to Langmuir and Freundlich isotherms. Adsorption analysis using Langmuir isotherm revealed that Qmax for the AC was higher than that of the micelle–clay complex, while Freundlich isotherm showed almost similar values of n (3.413 vs. 3.745) for both adsorbents, despite the fact that the activated carbon filter showed higher kF value. Filtration column of mixed micelle–clay complex and sand demonstrated a breakthrough point after the third fraction for chlorpyrifos removal and a complete removal for all fractions collected in the TCP experiment. This result reveals that mixed micelle–clay complex and sand column is much more efficient in removing TCP than removing its parent compound, chlorpyrifos
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
