The Effect of Surfactants on the Efficiency of Lead Acid Batteries

AbstractThe aim of this study is to show the effect of two phosphonate surfactants (PS) on the electrochemical behavior of the negative plate of lead-acid battery in the sulfuric acid medium. The characterization of the electrode interface was investigated at room temperature by a set of electrochemical techniques as linear sweep voltammetry (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA). Scanning electron microscopy (SEM) was employed to determine the film layer's morphology deposited on the surface of working electrodes, in the presence and in the absence of the PS. When the PS was added in the acidic solution, hydrogen evolution became higher, the over-potential of hydrogen was shifted to negatives values and the growth of the anodic β-PbO2 was inhibited. SEM imaging with the presence of PS showed reduction in the growth of the anodic β-PbO2 and PbSO4 layers. EIS results indicate the decrease of the conductivity of β-PbO2 film on the lead surface electrode. The result of the CV, show a decrease in the peak related to transition of PbO to Pb demonstrates that lower PbO has been formed underneath the lead sulfate membrane in the presence of low concentration of SP indeed a decrease in the amount of formed PbSO4 on the electrode surface

Catalytic activity of phenol oxidation over iron and cooper-exchanged pillared bentonite

Abstract Al, mixed Al-Fe and Al-Cu pillared clays were prepared. The solids were characterized by X-ray diffraction (XRD), N2 adsorption and H2-TPR. The dispersion of the cold clay suspension, before the pillaring, increases the basal spacing and the specific surface area. CWPO of phenol under mild conditions (25 °C, 1 atm) was carried out without correction of pH. Mixed Al-Fe and Al-Cu pillared clays have comparable performances, although they showed some differences in the H2O2 decomposition kinetics. A total conversion of H2O2 is obtained without the complete phenol conversion over mixed Al-Fe pillared clays suggesting the presence of active species in these catalysts. In a slight excess of H2O2, the activity increased for all iron-based clays catalysts with the increase in Fe content. A total conversion of phenol is obtained after 15 h of reaction over Fe/MR-AlFe(10) and after extending the reaction time to 30 h in the presence of Fe/MR-Al. While MR-AlFe(10) only converted 57.12% under the same conditions. MR-AlFe(10) has the greater basal space (17.44 Å) and is more active for H2O2 decomposition than Fe/MR-Al, which certainly allowed greater accessibility of the reactant to the iron species. Iron exchanged and post-pillared clay with mixed (Al-Fe) solution containing 10% of iron expressed as molar percentage {Fe/MR-AlFe (10)} was the most efficient for this reaction combining good catalytic activity with high stability against iron leaching (0.02%). It showed a total phenol degradation, the highest H2O2 decomposition (85.7%) and more than 80% of TOC removal after 15 h of reaction.</jats:p

Presence of Heavy Metals in Irrigation Water, Soils, Fruits, and Vegetables: Health Risk Assessment in Peri-Urban Boumerdes City, Algeria

This study investigates heavy metal contamination in soils, irrigation water, and agricultural produce (fruits: Vitis vinifera (grape), Cucumis melo&nbsp;var. saccharimus (melon), and Citrullus vulgaris. Schrade (watermelon); vegetables: Lycopersicum esculentum L. (tomato), Cucurbita pepo (zucchini), Daucus carota (carrot), Lactuca sativa (lettuce), Convolvulus Batatas (potato), and Capsicum annuum L. (green pepper)) in the Boumerdes region of Algeria. The concentrations of seven heavy metals (cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn)) in soil and food samples were analyzed using atomic absorption spectrometry. Health risks associated with these metals were evaluated through the estimated daily intake (EDI), non-carcinogenic risks (using target hazard quotient (THQ), total target hazard quotient (TTHQ), and hazard index (HI)), and carcinogenic risks (cancer risk factor (CR)). Statistical analyses, including cluster analysis (CA) and Pearson correlation, were conducted to interpret the data. The results revealed the highest metal transfer as follows: Cd was most significantly transferred to tomatoes and watermelons; Cr to carrots; Cu to tomatoes; and Fe, Ni, Pb, and Zn to lettuce. Among fruits, the highest EDI values were for Zn (2.54&middot;10&minus;3 mg/day) and Cu (1.17&middot;10&minus;3 mg/day), with melons showing the highest Zn levels. For vegetables, the highest EDI values were for Fe (1.68&middot;10&minus;2 mg/day) and Zn (8.37&middot;10&minus;3 mg/day), with potatoes showing the highest Fe levels. Although all heavy metal concentrations were within the World Health Organization&rsquo;s permissible limits, the HI and TTHQ values indicated potential health risks, particularly from vegetable consumption. These findings suggest the need for ongoing monitoring to ensure food safety and mitigate health risks associated with heavy metal contamination