BENTONITE/CHITOSAN BIOCOMPOSITE AS AN ADSORBENT FOR HEXAVALENT CHROMIUM FROM AQUEOUS SOLUTIONS

The present work focuses on the study of the application of abundant and less expensive materials such as chitosan and bentonite/chitosan biocomposite in the removal of hexavalent chromium. Spectroscopic analysis like techniques FTIR, XRD and BET have been used to characterize the adsorbents. The data indicate that the adsorption of chromium proceeds kinetically according to a pseudo-second order model on both samples and the apparent activation energy (Ea) have been measured to be 22.9 kJ.mol−1 and 84.4 kJ.mol−1 for chitosan and 5%Bt/CS, respectively. The adsorption isotherm experiments show that the adsorption capacity depends on the studied chromium adsorption temperature. It has been found that the data could be well described by the Langmuir as well as the Freundlich models. Thermodynamic parameters (i.e., change in the free energy (DG°), the enthalpy (DH°), and the entropy (DS°) have been also, evaluated

Adsorption of Hexavalent Chromium and phenol onto Bentonite Modified With HexaDecylTriMethylAmmonium Bromide (HDTMABr)

The efficiencies of Hexadecyltrimethylammonium bromide (HDTMABr) modified bentonite (HDTMABt) for phenol and chromium removal from aqueous solutions were studied in batch experiments at pH = 9 and pH = 2 values, respectively. FTIR, SEM, XRD and BET analyses indicated that the HDTMABr molecules were intercalated in the interlayer and at the external surface of initially Na-bentonite (NaBt). Adsorption experiments showed that the HDTMABt was more efficient than the initial NaBt for the removal of phenol and chromium, simultaneously, the extent of the enhancement differed among these pollutants depending on their affinity towards these samples. The kinetic study revealed a rapid adsorption onto HDTMABt of the pollutants during the initial stage (teq < 1h). The pseudo-second-order equation fitted well to the experimental data. Phenol adsorption on NaBt and HDTMABt could be described by a linear Freundlich equation while Langmuir and Freundlich models were the most suitable for Cr(VI) adsorption on both samples.Â

Hsp70-2 gene polymorphism: susceptibility implication in Tunisian patients with coronary artery disease

<p>Abstract</p> <p>Coronary artery disease (CAD) is a multifactorial disease where genetic and environmental factors interact in complex ways to cause the disease. Heat shock protein genes are involved in the progress of CAD. This implies that genetic variants of Hsp70–2 genes might contribute to the development of the CAD.</p> <p>Aim of study</p> <p>The aim of this study was to characterize statistical correlation of linkage between lipid profiles, polymorphism PstI site of Hsp70–2 gene and CAD.</p> <p>Patients and methods</p> <p>This study was carried out on Tunisian patients with CAD recruited from Hospital of Fattouma Bourguiba of Monastir-Tunisia. Polymerase chain reaction and restriction enzymes were used to determine the genotypic distributions in 252 unrelated patients and 151 healthy control subjects. Further, ApoA-I and ApoB as well as the serum total of cholesterol, HDL, triglyceride, and hs-CRP levels were measured.</p> <p>Results</p> <p>We showed a decreased level of ApoA-I, whereas the levels of each of ApoB and hs-CRP were increased in patients with CAD compared with control group. In addition our studies of a polymorphic PstI site of Hsp70-2 gene at position 1267 of the Hsp70–2 gene have revealed that the allelic frequency of P2 was significantly more frequent in CAD patients than controls group (p=0.007, OR=1.495). The genotypic distribution showed a high incidence of P2/P2 genotype in CAD patients (0.190) compared to healthy control (0.009) with reach significant difference (p=0.006). The P2 carriers showed a significantly increased of Total-Cholesterol (CT) and C-reactive protein (hs-CRP) levels in CAD patients (p=0.008 and p=0.018, respectively).</p> <p>Conclusion</p> <p>The high incidence of P2-Hsp70-2 genotype in CAD patients and the significantly association of P2/P2 genotype with elevated Total Cholesterol and hs-CRP levels, supported that P2–Hsp70–2 genotype has susceptibility implication in CAD and could increased the risk of CAD in Tunisian population.</p> <p>Virtual slides</p> <p>The virtual slide(s) for this article can be found here: <url>http://www.diagnosticpathology.diagnomx.eu/vs/1118340895703689</url></p