Formation of Palygorskite Clay from Treated Diatomite and its Application for the Removal of Heavy Metals from Aqueous Solution

Environmental contamination by toxic heavy metals is a serious worldwide phenomenon. Thus, their removal is a crucial issue. In this study, we found an efficient adsorbent to remove Cu2+ and Ni2+ from aqueous solution using two materials. Chemical modification was used to obtain palygorskite clay from diatomite. The adsorbents were characterized using X-ray florescence, Fourier transform infrared spectroscopy and X-ray diffraction. The effects of contact time, initial concentration, temperature and pH on the adsorption process were investigated. Our results showed that the (%) of maximum adsorption capacity of diatomite was 78.44% for Cu2+ at pH 4 and 77.3% for Ni2+ at pH 7, while the (%) of the maximum adsorption on palygorskite reached 91% for Cu2+ and 87.05% for Ni2+, in the same condition. The results indicate that the pseudo-second-order model can describe the adsorption process. Furthermore, the adsorption isotherms could be adopted by the Langmuir and the Freundlich models with good correlation coefficient (R-2). Thus, our results showed that palygorskite prepared from Tunisian diatomite is a good adsorbent for the removal of heavy metals from water.This research was funded by Department of Education of the Basque Government grant number [IT1008-16]" and "The APC was funded by Department of Education of the Basque Government

Competitive adsorption, selectivity and separation of valuable hydroxytyrosol and toxic phenol from olive mill wastewater

Competitive adsorption and selectivity of toxic phenol and hydroxytyrosol were studied on the macroreticular aromatic polymer (FPX66) and the macroporous polystyrene cross linked with divinylbenzene (MN202). The adsorption equilibrium of phenol and hydroxytyrosol as well as other phenolic compounds in olive mill wastewater (OMW) was investigated taking into account the different affinities of these compounds towards the two above mentioned resins. The experimental results showed that the adsorption equilibrium of phenol on FPX66 can be well interpreted by the BET model, indicating a multilayer adsorption, whereas, the adsorption of hydroxytyrosol on MN202 at equilibrium is well fitted by the Sips model. At low FPX66 concentration, phenol exhibited much higher adsorption percentage than hydroxytyrosol, indicating a stronger interaction with the resin. The adsorption selectivity ratio of phenol/hydroxytyrosol was of about 3.215 at 5 g L−1 of FPX66. Thanks to the large affinity of hydroxytyrosol for the MN202 resin, its adsorption and recovery were higher than 90% on this resin. Thus, under suitable operating conditions, phenol was selectively separated on FPX66, while hydroxytyrosol was largely recovered from the OMW residual solution by adsorption on MN202

Antioxidant, Antifungal and Phytochemical Investigations of Capparis spinosa L.

The antioxidant and antifungal activities of crude hydro-ethanolic extract from Capparis spinosa L. (Capparidaceae) leaves and their fractions, obtained by liquid-liquid extraction (LLE) using solvents with increasing polarity (hexane, diethyl ether, ethyl acetate, butanol, and water), were investigated. The crude extract and the obtained fractions were characterized by colorimetric analysis, pyrolysis-gas chromatography (GC)-mass spectroscopy (MS), Fourier Transform Infrared Spectroscopy, and their antioxidant and antifungal capacity were determined. It was observed that the ethyl acetate fraction was enriched in polyphenols, the butanol fraction resulted in purified from proteins and the residual aqueous fraction contains more hydrophobic compounds. The evaluation of the antioxidant activity revealed that the ethyl acetate fraction possesses an interesting capacity 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical scavenging with a percentage of inhibition of 84.02% at a concentration of 2 mg/mL and better ferric reducing antioxidant power (FRAP) 4.275 ± 0.011 mmol/g of dry sample than the other fractions tested. Regarding the antifungal activity, the diethyl ether fraction showed the highest activity against Aspergillus niger with 58.78% of inhibition. The results obtained in this work showed the relevance of the valorization of the leaves of Capparis spinosa L., given its richness in bioactive molecules can be regarded as a natural source of antioxidant and antifungal and may be considered in the future to replace synthetic preservatives in food, pharmaceutic products and cosmetic.This research was funded by University of Basque Country, grant number PES20/38 and “The APC was funded by University of Basque Country”

Functional Chitosan Derivative and Chitin as Decolorization Materials for Methylene Blue and Methyl Orange from Aqueous Solution

Dyes are classified as one of the major pollutants of water. They have negative impacts not only on environment but also on human health. In fact, wastewater that contains these harmful substances requires many types of treatments. Therefore, alternative methods and adsorption agents are needed. Herein, we propose to evaluate the decolorization of methylene blue (MB) and methyl orange (MO) as two models of soluble dyes from water using chitin and chitosan-graft-polyacrylamide. Furthermore, the applicability of these biomacromolecules as alternative adsorption agents, their sticking probability and desorption were also examined. Experimental parameters such as dye concentration, contact time, pH solution, adsorbent dosage and temperature were thoroughly examined for the grafted chitosan and chitin. The activation energy (Ea) and the thermodynamic variables (i. e., standard Gibb's free energy (D G0), standard enthalpy (D H0), and standard entropy (D S0)) were determined using the Van't Hoff and Arrhenius equations. The sticking probability (S*) model for MB and MO removal by chitin and the chitosan derivative demonstrated that both dyes were successfully removed under the proposed conditions. Desorption studies of MB and MO showed the reusability of both materials, suggesting their application for removing dyes from aqueous solution.The authors are grateful for the financial support of the Department of Education of the Basque Government (IT1008-16)

Investigation and Modeling of Electrical Stunning Parameters of Turkey Using Response Surface Methodology

Abstract: The aim of this work is to evaluate the effects of electrical stunning parameters of turkey on the quality of steak and stew using the response surface methodology. 1584 turkeys were used for the study. The parameters tested were the voltage and pulse. The responses were the sensory quality of steak and stew. The rejection rate varies between 0.23% (steak female) and 56.06% (female stew). Results show that it is possible to obtain a low rejection rates (< 1% for the steak of male turkey) at a voltage of 50 Volts and pulse of 7. In comparison of pulse, voltage remains the most important factor. The optimal conditions selected for the total output of the process obtained from the analysis of the response surfaces are: voltage, from 45 to 47 Volts; pulse from 6.5 to 7 and voltage from 50 to 52 Volts; pulse from 6.8 to 7, respectively for female and male turkeys. Under these experimental conditions, the rejection rates range from 0.23% to 0.80% and from 11.93% to 13.27% respectively for steak and stew. The results show that the voltage and pulse are both the parameters meaning on the global quality of steak and stew

Organ dependency variation of the chemical composition of Ziziphus lotus volatile fractions

The extended application fields of the essential oils keep them a subject of interest. In this study, we investigated the aerial part essential oil and the fruit essential oil of the wild plant Ziziphus lotus, collected from the southern region of Tunisia. These essential oils obtained by hydrodistillation using a Clevenger-type apparatus showed an extraction yield of 0.013% and 0.0046% respectively. The qualitative and quantitative analysis of the samples using GC-MS/GC-FID revealed two distinct compositions. Apocarotenoid derivatives characterized the essential oil of the aerial part; the major compound was hexahydrofarnesyl acetone (23.2%) followed by geranylacetone (12.5%) and cis-hexenyl-3-benzoate (11.1%). While the abundance of fatty acid marked the fruit essential oil. The noticed major compounds were 2-pentadecanone (16.9%), dodecanoic acid ethyl ester (14.5%) and n-hexadecanoic acid (13.0%). Such chemical composition may explain the traditional use of Ziziphus lotus as a drug to treat various pathologies. DOI: http://dx.doi.org/10.5281/zenodo.555296