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Open access

Mohammed A. Abdulaziz, Abdulrahman A. Bakri, Saleh A. Al-Zahrani, Majed S. Al-Zahrani, Abdulrahman N. Al-Lehebi, Fadil M. Banjar and Mohand I. Nabag

Abstract

This study aims at investigating the potential of Acacia gerrardii pod for the removal of Cr(VI) in batch system. Effect of solution pH, biosorbent dosage, initial concentration of Cr(VI), contact time on the removal process was examined. Complete removal of hexavalent chromium was achieved at pH values 1.0 and 2.0 whereas maximum removal of total chromium was obtained at pH of 3.0. The study showed that the biosorption and bioreduction mechanisms were involved in the removal process. The time required for complete removal of Cr(VI) using the pod of Acacia gerrardii was shortened with an increase in biomaterial dosage and decrease in Cr(VI) concentration. Kinetic data was well described using Park kinetic model. Freundlich isotherm model adequately fitted the equilibrium data indication multilayer adsorption of total chromium on the surface of biomaterial. The pod of Acacia gerrardii could be used efficiently for the removal of hexavalent chromium from aqueous solutions.

Open access

Bahman Jabbarian Amiri, Junfeng Gao, Nicola Fohrer and Jan Adamowski

Abstract

There is an emerging challenge within water resources on how, and to what extent, borrowing concepts from landscape ecology might help re-define traditional concepts in hydrology in a more tangible manner.

A stepwise regression model was adopted in this study to assess whether the time of concentration of catchments could be explained by five landscape structure-representing metrics for land use/land cover, soil and geological patches, using spatial data from 39 catchments.

The models suggested that the times of concentration of the catchments could be predicted using the measures of four landscape structure-representing metrics, which include contiguity index (r 2 = 0.46, p ≤0.05), fractal dimension index (r 2 = 0.51, p ≤0.05), related circumscribing circle (r 2 = 0.52, p ≤0.05), and shape index (r 2 = 0.47, p ≤0.05).

The models indicated that the regularity or irregularity in land use/land cover patch shape played a key role in affecting catchment hydrological response. Our findings revealed that regularity and irregularity in the shape of a given patch (e.g., urban and semi-urban, rangeland and agricultural patches) can affect patch functions in retarding and/or increasing flow accumulation at the catchment scale, which can, in turn, decrease or increase the times of concentration in the catchments.

Open access

Majid Muneer, Muhammad Saeed, Ijaz Ahmad Bhatti, Atta-ul Haq, Muhammad Kaleem Khosa, Muhammad Asghar Jamal and Saddaqat Ali

Abstract

Synthetic dyes are persistent pollutants with poor biodegradability. The present study is about the degradation of direct Congo red dye in aqueous media using the Co-60 gamma radiation source. The experimental conditions such as gamma-ray absorbed doses, amount of oxidant (H2O2) and pH conditions were evaluated. The λmax of dye solution was noted as 498 nm, and then, decrease in absorbance and reduction in chemical oxygen demand (COD) were examined. The complete colour removal of dye was observed at 5 kGy, while a significant COD removal was observed at 15 kGy gamma-ray absorbed dose in conjunction with oxidant for 50 mg/L concentration. It was found that pH has no influence on degradation efficiency. A possible degradation pathway was proposed. The radiolytic end products were monitored by Fourier transform infrared (FTIR) and gas chromatography coupled with mass spectrometry (GC-MS) to explore the degradation mechanism. It was imperative to study the oxidative degradation pathway to provide directions for potential applicability of advanced oxidation process (AOP) in industrial wastewater treatment.

Open access

Ahmed Mostafa and Heba Shaaban

Abstract

The study presents the application of multivariate curve resolution alternating least squares (MCR-ALS) with a correlation constraint for simultaneous resolution and quantification of ketoprofen, naproxen, paracetamol and caffeine as target analytes and triclosan as an interfering component in different water samples using UV-Vis spectrophotometric data. A multivariate regression model using the partial least squares regression (PLSR) algorithm was developed and calculated. The MCR-ALS results were compared with the PLSR obtained results. Both models were validated on external sample sets and were applied to the analysis of real water samples. Both models showed comparable and satisfactory results with the relative error of prediction of real water samples in the range of 1.70–9.75 % and 1.64–9.43 % for MCR-ALS and PLSR, resp. The obtained results show the potential of MCR-ALS with correlation constraint to be applied for the determination of different pharmaceuticals in complex environmental matrices.

Open access

Fahimed Koohdar, Masoud Sheidai and Seyed Mehdi Talebi

Abstract

Lallemantia royleana (Benth.) Benth. (Family Lamiaceae), is one of the most popular medicinal plants in Iran. It is an herbaceous pant that is commonly known as “Lady mantle”. The vernacular name of Lallemantia royleana’s seed is Balangu or Balangu Shirazi that is used as a source of medicine. Medicinal plants are very important from economic point of view in Iran and several large industries are focused on medicinal plants cultivation, extraction and export. Therefore, providing data on the biology of these plants is important for the country. Lallemantia royleana grows in different parts of Iran and forms several local populations. Genetic, morphological and biochemical divergence of geographical populations are well known in plant species. We have no report on population genetic structure, genetic fragmentation, local adaptation and gen flow of Lallemantia royleana populations in the country. Therefore, the present population genetics investigation was programmed to produce data on above said questions. Randomly collected plants of 7 geographical regions were studied by ISSR molecular markers. This information can be used in hybridization and gene conservation of this medicinal plant in Iran.

Open access

Elena Benito, Eufemia Varela and María Rodríguez-Alleres

Abstract

The primary purpose of this work was to assess the persistence of water repellency in the surface horizon of coarse-textured soils under natural Quercus robur ecosystems, and Pinus pinaster and Eucalyptus globulus plantations, in the northwest of the Iberian Peninsula. Water repellency was determined by applying the water drop penetration test (WDPT) to soil samples collected from variable depths (0–40 cm). Measurements were made on field-moist samples obtained at the end of the dry period and on samples dried at 25ºC in the air. All soils exhibited very high (severe to extreme) water repellency in the topmost soil layer (0–5 cm) but no significant differences among the three plant species studied. Extreme persistence was observed down to 20 cm in the soils under eucalyptus and down to 10 cm in those under pine. The soils under oak were those exhibiting the highest variability in water repellency and the greatest decrease in it with increasing depth (especially in relation to soils under eucalyptus).

Water repellency exhibited significant positive correlation with the C content and C/N ratio of the soils. Soil water repellency was similar in the air-dried samples and field-moist samples.

Open access

Duilio Iamonico and Ridha El Mokni

Abstract

Populations of Atriplex canescens var. gigantea were found in Lamta, Bouficha-Enfidha (central Tunisia), and Medenine (southern Tunisia). Literature data concerning the presence of this species in Tunisia are contradictory but now our data confirm its occurrence in the country. On the other hand, this variety is reported in the present paper for the first time both in Tunisia and in North Africa in general. Morphological characters and ecological data are presented, as well as notes about patterns of infraspecific variability of A. canescens. Nomenclatural notes on infraspecific names in A. canescens, as well as on the closely related species A. garrettii, are provided. The types of the names A. canescens var. laciniata, A. canescens var. macilenta, A. garrettii, Obione occidentalis var. angustifolia, and Pterochiton occidentale, that in earlier publications were erroneously considered to be holotypes, are in fact lectotypes (for most of taxa) under Art. 9.10 of the ICN. Isolectotypes were found at CAS (A. canescens var. laciniata and A. canescens var. macilenta), GH (A. canescens var. macilenta), and YU (Atriplex nuttallii).

Open access

Marcin Nabrdalik and Michał Sobociński

Abstract

The paper presents analysis of stress distribution in the friction node of knee joint endoprosthesis where sleds are made of various titanium alloys and CoCrMo cooperate with spherical polyethylene inserts. Currently used titanium alloys consists of Nb, Ta, Zr or Mo and with lesser value of Young’s modulus than Ti6Al4V alloy, or steel CoCrMo, which significantly varies from other metal materials. The obtained results make it possible to indicate the “weak points” of the accepted solution, and thus counteract the subsequent effects resulting from premature wear of endoprosthesis elements. The analysis was conducted with numerical method of ADINA System 8.6. The Finite Elements Method allowed to compute and present stress distribution quickly in all elements of the model.

Open access

Elisa Pellegrini, Valentino Casolo, Duilio Iamonico, Giuseppe Oriolo, Nicola Rovere and Massimo Vischi

Abstract

Senecio fontanicola is endemic to black-bog-rush fens of southern Austria, northwestern Slovenia and north-eastern Italy. It is characterized by oblanceolate leaves, a low number of supplementary bracts and glabrous achenes and it grows in marshy spring areas, fens and reed beds, between elevations from 20 to 850 m. The species was never described with molecular traits and during the last decades, S. fontanicola showed a dramatic decline due to land reclamation for agriculture. Therefore, the present study aims to characterize S. fontanicola using the molecular barcoding technique and to updated its distribution to propose a global risk category for the species, based on IUCN criteria. The three molecular markers used in this study (trnH-psbA, rbcL, and ITS) clearly distinguished S. fontanicola from S. doria. s.s. and the revised distribution allowed the definition of the conservation status of the species, that is Endangered-EN B2ab(i, ii, iii, iv) following the B criterion of the IUCN guidelines.

Open access

Katarzyna Wilpiszewska

Abstract

The hydrophilic films based on starch and carboxymethyl starch (CMS) were obtained using cast method. The effect of CMS content on the physicochemical properties of prepared films were evaluated. With increasing content of starch derivative the moisture absorption, solubility in water as well as swelling ratio increased. The highest values of mechanical parameters (tensile strength and Young’s modulus) were determined for the starch/CMS film containing the lowest CMS amount, i.e. 10 wt.% (1.1 MPa, 15 MPa, respectively). For the same system the lowest moisture absorption, solubility in water as well as swelling ratio were reported. Thus, it could be concluded that for this system the highest crosslinking density has been achieved, what was confirmed by DMTA results. Such a film could potentially find application in food or agricultural industry.