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Adsorption of Ciprofloxacin from Aqueous Environment by Using Synthesized Nanoceria

Abstract

Antibiotics are widely detected emerging contaminants in water environments and possess high potential risks to human health and aquatic life. However, conventional water treatment processes cannot remove them sufficiently. To develop innovative nanoadsorbents for effectively remove antibiotic contaminants from water environment, nanoceria were prepared via in situ precipitation method, and evaluated their adsorption capacity for a model antibiotic, ciprofloxacin (CIP). The properties of the prepared nanoceria were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and vibration sample magnetization (VSM). The effect of various operating parameters such as pH, initial CIP concentration, contact time, and adsorbent dosage on adsorptions of CIP were studied in batch experiments. Maximum adsorption capacity of the nanoceria was 49.38 mg/g at the conditions of pH 5, initial CIP concentration of 200 mg/dm3 and adsorbent dosage of 0.2 g/dm3, when 95.43 % of the CIP was removed. For adsorption kinetics, both pseudo-first-order and pseudo-second-order models can well describe the experimental data, indicating that the adsorption process was controlled by both physical diffusion and chemical interaction. For adsorption isotherms, the Freundlich model could fit the experimental data better than the Langmuir and Temkin models, suggesting a multilayer adsorption process. The thermal dynamics study showed the absorption process was spontaneity, exothermic, and irreversible. Finally it was concluded that the nanoceria can be used effectively for CIP removal.

Open access
The Analysis of the Chemical Composition of Precipitation During the Driest Year from the Last Decade

Abstract

In order to investigate the precipitation chemistry, studies were carried out from January 2013 to December 2013 in Odorheiu Secuiesc and Miercurea Ciuc, Eastern Carpathians, Romania. During a period of eleven years (2006 – 2016), 2013 was the driest year. The rainwater samples were analyzed for pH, major anions and cations. HCO3 concentrations were calculated based on the empirical relationship between pH and HCO3 . NH4 +, Ca2+, SO4 2− were the dominant ions in precipitation at both sites. The pH values varied from 6.75 to 7.46 Miercurea Ciuc, and from 6.69 to 7.67 in Odorheiu Secuiesc. The neutralization was mainly brought by Ca2+ and NH4 +. Estimated ratios of sea-salt fraction (SSF), non-sea-salt fraction (NSSF), and results from Spearman’s rank correlation and Principal Component Analysis (PCA), showed that the acidic ions (SO4 2−, NO3 ) were derived from anthropogenic activities, NH4 + from soil fertilization, while Ca2+, Mg2+, K+ originated from terrestrial source. These influence the precipitations ionic content, especially during droughts. Spatial variations and the rim effect of the Eastern Carpathians on precipitation chemistry is also shown.

Open access
Antisickling Effects of Quercetin may be Associated with Modulation of Deoxyhaemoglobin, 2, 3-bisphosphoglycerate mutase, Redox Homeostasis and Alteration of Functional Chemistry in Human Sickle Erythrocytes.

Abstract

It is now glaring that sickle cell anaemia is still one of the highest leading inbred hemoglobinopathy amongst Africans. This study examined the antisickling effects of quercetin via modulation of deoxy-haemoglobin, redox homeostasis and alteration of functional chemistry in human sickle erythrocyte using in silico and in vitro models while espousing preventive and curative approaches. Quercetin was docked against deoxy-haemoglobin and 2, 3-bisphosphoglycerate mutase, with binding energies (−30.427 and −21.106 kcal/mol) and Ki of 0.988μM and 0.992μM at their catalytic sites via strong hydrophobic and hydrogen bond interactions. Induction of sickling was done using 2% metabisulphite at 3h. Treatment with quercetin prevented sickling outstandingly at 5.0μg/mL and reversed same at 7.5μg/mL, 83.6% and 75.9%, respectively. Quercetin also significantly (P<0.05) maintained the integrity of erythrocyte membrane apparently from the observed % haemolysis relative to untreated. Quercetin significantly (P<0.05) prevented and counteracted lipid peroxidation while stimulating GSH and CAT levels which were detected to considerably (P<0.05) increase with simultaneous significant (P<0.05) reduction in SOD level based on curative approach. Umpiring from our FTIR results, a favorable alteration in the part of functional chemistry in terms of shifts (bend and stretches) and functional groups were observed relative to the induced erythrocyte/untreated. Thus, antisickling effects of quercetin may be associated with modulation of deoxy-haemoglobin, redox homeostasis and alteration of functional chemistry in human sickle erythrocytes.

Open access
The Application of Directional Univariate Structure Functions Analysis for Studying the Spatial Anisotropy of Environmental Variables

Abstract

As anisotropy is a fundamental property of the real-world environmental spatial variables, the conventional omnidirectional variograms and correlograms do not provide means enough to characterise spatial dependence between observations. The purpose of this article is to introduce directional univariate structure functions analysis to explore and quantify the spatial anisotropy of environmental variables. Analysis of six environmental variables within three physical–geographical regions proved the leading role of relief for landscape differentiation; it also defined the size and extension of major landforms responsible for the organisation of spatial pattern. The arrangement of the vegetation patches demonstrated linkage with the major landforms. The other relief derivatives, being prone to noise and artefacts in the original data, showed a random-variable type of behaviour. In the lack of any particular spatially anisotropic structure, the results of the analysis can provide a clue about meaningful distances of interest at finer scales. The approach can also be an exploratory tool for discrete measurements to recognise the features of spatial continuity.

Open access
Application of Geographic Information Systems for Flood Risk Analysis: A Case Study from Accra Metropolitan Area

Abstract

The main objective of the study was to identify high flood risk zones in AMA. The study also used questionnaires to assess local knowledge on what accounts for the high flood risk in their community. Spatial analysis techniques were used to model flood risk based on the following contributory factors; land cover, soil, drainage density, topography and proximity to rivers. The results show that high flood risk areas covered 46.3km2(20%), moderate risk area, 72.9km2(31.6%), low risk area 41.5km2(18%) and very low risk areas, about 6.7km2(2.9%). The high flood risk zones were low-lying areas below 50 meters above sea level and closely associated with poor drainage systems. People perceived not just low-lying areas as a paramount reason accounting for flooding but also very bad waste disposal habit of the public. These offsets the efforts of waste management companies to keep drains free of refuse.

Open access
Application of solid-phase extraction for isolation of coumarins from wine samples

Abstract

Coumarins can be as a result wine storage and aging in wood drums and they can affect organoleptic characteristics of wine. The aim of this work was to determine the content of coumarins in wine samples originated from Slovak Tokaj wine region. The HPLC method with high specificity, accuracy, precision, and recovery was proposed. SPE sorbents of C18 type, styrene-divinylbenzene copolymer and molecularly imprinted polymers were compared for extraction of six coumarins, coumarin, aesculin, scoparone, scopoletin, 4-methylumbelliferone, and herniarin. Higher recoveries (above 89 %; except aesculin – recoveries higher from 68 %, RSDs less than 6 %) were obtained with selective polymeric sorbent laboratory prepared by molecularly imprinted technology. The results showed that content of coumarins in wine samples are in ng.mL−1 concentration levels and depend on the age and wine puttony.

Open access
Application of the Shrinking-Core Models for Determination of Dissolution Kinetics of Mn and Zn from Spent Zinc–Carbon Battery Powder in Organic Acid Solution

Abstract

In this study, dissolution kinetics of manganese and zinc from spent zinc–carbon batteries in acetic acid solution was investigated. To determine the kinetics of dissolution of manganese and zinc, shrinking core model was applied to dissolution recoveries obtained at different temperatures. As a result of kinetic studies, it was determined that manganese and zinc were dissolved in acetic acid solution by diffusion from product layer and then activation energies (Ea) were calculated.

Open access
Aspects Regarding the Linseed Oil Culture in Romania in the Context of the Ongoing Climate Change

Abstract

Nowadays, at global level, the linseed oil culture is more important economically than the linseed cultures for fiber. The world's largest linseed production is the linseed oil, followed by the culture for the consumption of seeds and for fibers. In this context, this study presents the evolution and the main trends in the production of the linseed oil for Romania in the period 2008-2017, the analysis being based on the values of specific indicators, namely the areas cultivated with linseeds and the production of the linseed oil achieved at the national level, macro-regions and development regions, both as a total and in the private sector as well. This analysis will be done in the context of the ongoing climate change also affecting Romania's territory. Analysing the results, one can notice that, although after 1990 the cultivated areas have decreased dramatically, since the integration of Romania into the EU, the linseed oil cultivated areas have started to grow. Thus, in 2017, Romania was the sixth EU linseed oil producer in the EU, with the South-East region holding a significant share of the cultivated areas.

Open access
Biologically valuable components, antioxidant activity and proteinase inhibition activity of leaf and callus extracts of Salvia sp.

Abstract

Sage is medicinal plant, known for its antioxidant and anti-inflammatory effects. Eight extract samples were tested in this study: extract from Salvia officinalis L. varieties from two different geographical localities (Jaslovské Bohunice and Pobedim, Slovakia), Salvia officinalis L., variety “bicolor”, Salvia officinalis L., variety “purpurescens”, Salvia apiana, Salvia divinorum, and two callus cultures of Salvia sclarea L. and Salvia aethiopis L. The highest values for composite parameters were observed for extract from Salvia apiana. It can be concluded that prepared sage extract samples are rich on polyphenolic acids (2 950±265 μg.mL−1 GAeq.) and amines (197±5.50 μg.mL−1 TRPeq.). HPLC analysis confirmed the dominant content of rosmarinic acid in the extracts; the highest content was detected in the Salvia apiana extract (1 120±15 μg.mL−1). Extract from Salvia apiana expressed too the highest antioxidant activity (1 710 – 4 669 μg.mL−1TEAC). Similarly, the highest inhibition activity was observed for this extract on thrombin (57±3.3 %) and on other proteinases (over 80 %). Spearman correlation analysis and PCA analyses revealed a coherence between antioxidant activity of samples and their content of rosmarinic acid as well as inhibitory activity towards particular proteases, and revealed the significance of thiol based secondary metabolites. Cluster analysis demonstrates the differences of Salvia apiana extract from extracts of S. officinalis L., the group of S. divinorum extract and from callus cultures.

Open access
Characteristics of Acute Toxicity Dynamics of Selected Toxicants on Aquatic Crustaceans

Abstract

Determining the value of a half-effective or half-life concentration or dose of toxicant is the main purpose of acute toxicity studies, and this is also the most commonly used value in the toxicity characteristics of substances. By conducting tests that meet the criteria and requirements for the determination of acute toxicity, due to the use of appropriate mathematical tools and concentrations resulting in complete lethal effects in the studied groups, considerably more important values can be achieved, which give a possibility for the analysis of the entire process’s dynamics, as well as determining the threshold values of the effect time and toxicant concentration. This was the purpose of our research, in which the research species were Daphnia magna and Cypris pubera. The effect of the conducted research allowed to determine and compare the two toxicants: ammonium and copper(II) ions by it’s: concentration limit values (C th), internal toxicity of the receptor-ligand complex (α), apparent, constant disintegration of this complex (K app) and different time values of the effect (Tt, Tin, MLT), which, along with concentration, is equally important determinant of the development of a toxic effect.

Open access